Cutting-Edge MR & the Brain Tumor Microenvironment
Neuro Thursday, 20 May 2021
Digital Poster

Oral Session - Cutting-Edge MR & the Brain Tumor Microenvironment
Neuro
Thursday, 20 May 2021 14:00 - 16:00
  • Multi-parametric hyperpolarized 13C/1H imaging of human gliomas expressing diverse pathologic mutations
    Adam W Autry1, Sana Vaziri1, Marisa LaFontaine1, Jeremy W Gordon1, Hsin-Yu Chen1, Yaewon Kim1, Javier Villanueva-Meyer1, Susan M Chang2, Jennifer Clarke2, Duan Xu1, Janine M Lupo1, Peder EZ Larson1, Daniel B Vigneron1,3, and Yan Li1
    1Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA, United States, 2Department of Neurological Surgery, University of California San Francisco, San Francisco, CA, United States, 3Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, CA, United States
    Multi-parametric 1H and hyperpolarized carbon-13 (HP-13C) distinguished between IDH-mutant and IDH-wildtype GBM, demonstrated heterogeneity among IDH-wildtype GBM imaging features, and provided further evidence of aberrant HP-13C metabolism among molecular glioma subtypes. 
    Figure 1. A patient with IDH-wildtype GBM (Top) displays a CE lesion, which contains elevated 1H perfusion. Accompanying HP-13C EPI data demonstrate the related elevation in total [1-13C]pyruvate and [1-13C]lactate signal. However, because of the perfusion abnormality, the kPL map fails to provide visual conspicuity. By comparison, the patient with the non-enhancing IDH-mutant GBM (Bottom) displays a weakly perfused lesion, with lower relative signal from [1-13C]pyruvate and [1-13C]lactate. The kPL map for this patient clearly highlights the lesion.
    Figure 2. A 1H MRSI CNI map overlaid on a T1w post-Gd image of a patient with IDH-wildtype GBM (A). Corresponding lactate-edited spectra from two adjacent voxels show CNI > 11 (green voxel) and lipid from the difference spectra (red voxel). Despite lower 1H-lactate, the HP-13C data demonstrated abundant [1-13C]lactate production. Another patient with IDH-wildtype GBM presented with a larger infiltrative mass (CNI > 6; green voxel) as well as 1H-lactate (B). In this case, HP [1-13C]lactate production was less pronounced, perhaps owing to the existing pool of steady-state 1H-lactate.
  • Glucose oxidation rate as a potential marker for GBM staging: correlation with histopathology and cell proliferation in a mouse model
    Rui V Simoes1, Rafael N Henriques1, Beatriz M Cardoso1, Tania Carvalho1, and Noam Shemesh1
    1Champalimaud Research, Champalimaud Foundation, Lisbon, Portugal
    While aerobic glycolysis (Warburg effect) is  a hallmark of cancer, our results indicate glucose oxidation rate as a potential marker of cell proliferation and vascular stability in a syngeneic mouse model of GBM, suggesting a new approach for non-invasive phenotyping of this disease.
    Figure 5 – Glucose oxidation rate as a potential marker for GBM staging according to cell proliferation and stromal vascular fraction phenotype. H&E microphotographs showing how the expansile tumor growth progressively compresses and impairs vascular blood flow: I, small vessels, complete endothelial cell lining and sparse hemorrhages (GL6); II, blood flow obstructed, vasodilation and marked multifocal hemorrhages (GL7); III, necrosis with incomplete endothelial cell lining, vascular leakage, edematous stroma (GL5); IV, vascular depletion, edematous stroma (GL50).
    Figure 1 – Experimental approach. A. in vitro, Seahorse XFp Mito-Stress Test with GL261 cells, measuring OCR and ECAR during sequential inhibition of the respiratory chain: oligomycin (ATP synthase), FCCP (H+ uncoupler), and antimycin A/rotenone (complexes I/III). B. in vivo, DGE 2H-MRS, showing the volume selection (pink), spectral fitting for each metabolite and the kinetic fitting; and DCE-T1 MRI, showing the tumor ROI (red), kinetic fitting and Ktrans maps. C. post-mortem, Tumor histology for H&E and Ki67 – enlarged region showing Ki67 positive (red) and negative (blue) cells.
  • Hypoxia alters normal fibroblast metabolism towards a cancer associated fibroblast phenotype
    Jesus Pacheco-Torres1, Tariq Shah1, W. Nathaniel Brennen2, Flonne Wildes1, and Zaver M Bhujwalla1,3,4
    1Division of Cancer Imaging Research, The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, United States, 2Department of Oncology, The Johns Hopkins University School of Medicine, Baltimore, MD, United States, 3Sidney Kimmel Comprehensive Cancer Center, The Johns Hopkins University School of Medicine, Baltimore, MD, United States, 4Radiation Oncology and Molecular Radiation Sciences, The Johns Hopkins University School of Medicine, Baltimore, MD, United States
    Hypoxia induces metabolic changes in normal prostate fibroblasts that mimic the metabolic profile of cancer associated fibroblast. Hypoxia also increases the degradative and invasive potential of normal fibroblasts.
    Figure 1. Heat map showing altered metabolites in the cell extracts of WMPY-1 and PCAFs incubated under normoxic and hypoxic conditions. Each column represents the mean value for at least 5 biological replicates. A two-tail unpaired t-test was used to compare values obtained under normoxic and hypoxic conditions in each cell line. * p ≤ 0.05, ** p < 0.01 and *** p < 0.001. MTA: GSH: glutathione; GSSG: oxidized glutathione.
    Figure 3. Evolution of the mean invasion index (a) and the mean degradation index (b) relative to the initial time point over the 48 h of the experiment. * p<0.05 relative to normoxic conditions.
  • Reproducibility study of disrupted white matter integrity and partial recovery in children treated for medulloblastoma
    Wilburn E Reddick1, Jared J Sullivan1, John O Glass1, Yian Guo2, Julie H Harreld1, Yimei Li2, Giles W Robinson3, Amar Gajjar3, and Thomas E Merchant4
    1Department of Diagnostic Imaging, St. Jude Children's Research Hospital, Memphis, TN, United States, 2Department of Biostatistics, St. Jude Children's Research Hospital, Memphis, TN, United States, 3Department of Oncology, St. Jude Children's Research Hospital, Memphis, TN, United States, 4Department of Radiation Oncology, St. Jude Children's Research Hospital, Memphis, TN, United States
    FA measures at baseline demonstrated an immediate decline due to tumor and surgery, which is then accentuated by  irradiation followed by a partial recovery, which was attenuated in patients receiving higher doses.
    Figure 1: Representative individual dosimetry mapped in cGy onto the TBSS skeleton for an average-risk (A) and high-risk (B) patient.
    Figure 5: TBSS results for interaction of dose with longitudinal evolution of the FA after irradiation. The skeleton is shown green overlaid on the average FA with red voxels demarcating significant negative interaction between dose and the positive change over time (slope) indicating that higher doses attenuated the rate of recovery. Distributions of these voxels were primarily in the cerebral peduncles, internal capsule, posterior thalamic radiation, corpus callosum, and corona radiata including the superior longitudinal fasciculus.
  • Quantification of pyruvate recycling in brain tumor patients
    Kumar Pichumani1, Omkar Ijare1, Elizabeth Maher2, Robert M Bachoo2, and David S Baskin1
    1Peak Center, Neurosurgery, Houston Methodist Hospital, Houston, TX, United States, 2UT Southwestern Medical Center, Dallas, TX, United States

    Pyruvate recycling is active in primary GBM and metastatic brain tumors. Intravenously infused 13C labeled glucose during the surgery is used to track the flux through this pathway in patients using resected tumor tissues.

    Schematic diagram illustrating pyruvate recycling pathway during [U-13C]glucose metabolism.
    C2 lactate 13C NMR spectral region of brain tumor tissue extracts. The patients were given intravenous infusion of [U-13C]glucose prior to the surgical removal of the tumor. D12 and D23 doublets (via pyruvate recycling) represent [1,2-13C] and [2,3-13C]lactate isotopomers. The quartet (Q) signals correspond to the [U-13C]lactate that are generated from glycolysis of [U-13C]glucose.
  • Pathological validation of MP-MRI intensity-based signatures in brain cancer patients using autopsy tissue samples
    Samuel Bobholz1, Allison Lowman2, Michael Brehler2, Savannah Duenweg1, Fitzgerald Kyereme2, Elizabeth Cochran3, Jennifer Connelly4, Wade Mueller5, Mohit Agarwal2, Darren O'Neill2, Anjishnu Banerjee6, and Peter LaViolette2,7
    1Biophysics, Medical College of Wisconsin, Milwaukee, WI, United States, 2Radiology, Medical College of Wisconsin, Milwaukee, WI, United States, 3Pathology, Medical College of Wisconsin, Milwaukee, WI, United States, 4Neurology, Medical College of Wisconsin, Milwaukee, WI, United States, 5Neurosurgery, Medical College of Wisconsin, Milwaukee, WI, United States, 6Biostatistics, Medical College of Wisconsin, Milwaukee, WI, United States, 7Biomedical Engineering, Medical College of Wisconsin, Milwaukee, WI, United States
    MP-MRI signatures of cellularity, CYT, and ECF capture a modest degree of variance using autopsy samples as ground truth, with stronger radio-pathomic relationships observed in non-GBM patients than GBM patients.
    Schematic representation of the study structure including A) data collection for MRI and tissue modalities and associated preprocessing, B) MR-histology coregistration, and C) mixed effect analysis structure
    Mixed effect model results for cell density. The left-hand plots represent the first order models, whereas the right hand results represent the interaction between MR intensity and diagnosis, where blue = GBM and red = non-GBM.
  • Impact of inversion time for FLAIR acquisition on the T2-FLAIR mismatch detectability for IDH-mutant, non-CODEL astrocytomas
    Manabu Kinoshita1, Hideyuki Arita1, Masamichi Takahashi2, Takehiro Uda3, Junya Fukai4, Kenichi Ishibashi5, Noriyuki Kijima1, Ryuichi Hirayama1, Mio Sakai6, Atsuko Arisawa7, Hiroto Takahashi7, Katsuyuki Nakanishi6, Naoki Kagawa1, Kouichi Ichimura8, Yonehiro Kanemura9, Yoshitaka Narita2, and Haruhiko Kishima1
    1Neurosurgery, Osaka University Graduate School of Medicine, Suita, Japan, 2Neurosurgery and Neuro-Oncology, National Cancer Center Hospital, Tokyo, Japan, 3Neurosurgery, Osaka City University Graduate School of Medicine, Osaka, Japan, 4Neurological Surgery, Wakayama Medical University, Wakayama, Japan, 5Neurosurgery, Osaka City General Hospital, Osaka, Japan, 6Diagnostic Radiology, Osaka International Cancer Institute, Osaka, Japan, 7Radiology, Osaka University Graduate School of Medicine, Suita, Japan, 8Division of Brain Tumor Translational Research, National Cancer Center Research Institute, Tokyo, Japan, 9Biomedical Research and Innovation, National Hospital Organization Osaka National Hospital, Osaka, Japan
    This study discovered that FLAIR acquisition with TI shorter than 2400 ms in 3T could Improve the detectability of IDHmt, non-CODEL astrocytomas. Tuning TI for FLAIR acquisition is such a simple technique that clinicians can easily incorporate into daily workflow of glioma imaging.
    This figure shows two representative IDHmt, non-CODEL astrocytomas that had two FLAIR images scanned with different TIs. Both cases highlight the importance of TI for FLAIR acquisition in terms of visualization of the T2-FLAIR mismatch sign.
    The figures show the frequencies of presence or absence of the T2-FLAIR mismatch sign found in the TCIA/TCGA LrGG cohort. We divided the cohort into two groups according to the TI for FLAIR acquisition. The T2-FLAIR mismatch sign was more frequently positive for or IDHmt, non-CODEL astrocytomas if we acquired FLAIR with TI shorter than 2400 ms. The ROC curve for identifying IDHmt, non-CODEL astrocytomas is presented at the lower panel. The area under the curve improved from 0.63 to 0.87 87 if we acquired FLAIR with TI shorter than 2400 ms.
  • Leakage Correction of Dynamic Susceptibility Contrast (DSC-) MRI for vessel size measurements in human glioma
    Fatemeh Arzanforoosh1, Paula L. Croal2, Karin Van Garderen1, Marion Smits1, Michael A. Chappell2, and Esther A.H. Warnert1
    1Department of Radiology & Nuclear Medicine, ErasmusMC, Rotterdam, Netherlands, 2Radiological Sciences, Division of Clinical Neurosciences, University of Nottingham, Nottingham, United Kingdom
    In summary, this work recommends application of a pre-bolus combined with BSW leakage correction in enhancing glioma for vessel size estimation, while eliminating the need for leakage correction for nonenhancing glioma.
    Figure 1: A) Group averages of corrected and uncorrected vessel size measurements within 4 ROIs: NAWM, NAGM, Tumor, CE-Tumor. Note that CE-Tumor ROI was delineated only for enhancing glioma patients (6 patients) , B) Scatter plots of corrected and uncorrected vessel size measurements , across subject within 4 ROIs (individual subject’s data are connected by solid lines). * represents significant p-value calculated from Student’s t-test (p < 0.05) .
    Figure 2: Single slice of exemplary MRI images of two patients with enhancing gliomas ; A) Patient 01 and B) Patient 03. The images from left to right respectively are : T2W FLAIR; post contrast T1W; post contrast T1W with regions of interest, ROIs, overlaid (contrast-enhanced tumor (CE-Tumor) in yellow, tumor in orange, normal-appearing white matter (NAWM) in green, and normal-appearing grey matter (NAGM) in blue), calculated vessel size map (before application of leakage correction) and calculated vessel size map (after application of leakage correction).
  • 3D APTw Brain Tumor Imaging with Compressed SENSE: Comparison of Different Acceleration Factors and with Conventional Parallel Imaging
    Nan Zhang1, Qingwei Song2, Ailian Liu2, Haonan Zhang2, Renwang Pu2, Jiazheng Wang3, and Zhiwei Shen3
    1The First Affilliated Hospital of Dalian Medical University, Dalian, China, 2The First Affiliated Hospital of Dalian Medical University, Dalian, China, 3Philips Healthcare, Beijing, China, Beijing, China
    The study aims to explore the feasibility of compressed SENSE with different acceleration factors in 3D brain APTw imaging. Based on the results, an accelerator factor of 5 is recommended with acceptable image quality and significantly reduced scan (less than 2? min).
    Figure 1a 54-year-old female patient with meningiomas in brain: a. T2WI; b. T2WI FLAIR; c. T1-Gd; d. APTw image by SENSE-1.6 fused with T2WI FLAIR image; e-h. APTw images by CS-SENSE (with factors of 2, 3, 4, and 5) fused with T1-Gd image. The ROIs were obtained manually on the SENSE APTw image and copied to the others as shown.
    Figure 2 a 64-year-old female patient with metastatic tumors in brain: a. T2WI; b. T2WI FLAIR; c. T1-Gd; d. APTw image by SENSE-1.6 fused with T2WI FLAIR image; e-h. APTw images by CS-SENSE (with factors of 2, 3, 4, and 5) fused with T1-Gd image. The ROIs were obtained manually on the SENSE APTw image and copied to the others as shown
  • MR Imaging Parameters for Noninvasive Prediction of EGFR Amplification in IDH-Wildtype Lower-Grade Gliomas: A Multicenter Study
    Yae Won Park1, Ji Eun Park2, Sung Soo Ahn1, Seung Hong Choi3, Ho Sung Kim2, and Seung-Koo Lee1
    1Yonsei University College of Medicine, Seoul, Korea, Republic of, 2University of Ulsan College of Medicine, Seoul, Korea, Republic of, 3Seoul National University Hospital, Seoul, Korea, Republic of
    Infiltrative or mixed pattern, lower ADC, lower 5th percentile of ADC, and higher 95th percentile of nCBF may be useful imaging biomarkers for the EGFR amplification of IDHwt LGGs. 
    Figure 1. Images of a 75-year-old female with an EGFR amplified grade III IDHwt glioma reveals T2 hyperintense tumor in the right frontal lobe, showing an infiltrative pattern (size of precontrast T1 abnormality much smaller than size of FLAIR abnormality). The histogram and cumulative histogram (dark blue line) of ADC shows a 5th percentile DC value and mean ADC value of 0.60 x 10-3 mm2/s and 1.01 x 10-3 mm2/s, respectively. The histogram and cumulative histogram (dark blue line) of nCBF shows a 95th percentile of the nCBF value of 7.54.
    Figure 2. Images of a 58-year-old female with an EGFR non-amplified grade III IDHwt glioma reveals T2 hyperintense tumor in the left temporal lobe, showing an expansile pattern (size of precontrast T1 abnormality approximates size of FLAIR abnormality). The histogram and cumulative histogram (dark blue line) of ADC shows a 5th percentile ADC value and mean ADC value of 0.73 x 10-3 mm2/s and 1.28 x 10-3 mm2/s, respectively. The histogram and cumulative histogram (dark blue line) of nCBF shows a 95th percentile of the nCBF value of 4.55.
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Digital Poster Session - Advanced Brain Tumor Imaging
Neuro
Thursday, 20 May 2021 15:00 - 16:00
  • Deep learning super-resolution MR spectroscopic imaging to map tumor metabolism in mutant IDH glioma patients
    Xianqi Li1, Bernhard Strasser1, Kourosh Jafari-Khouzani2, Daniel P Cahill3, Jorg Dietrich4, Tracy T Batchelor4, Martin Bendszus5, Ulf Neuberger6, Philipp Vollmuth6, and Ovidiu Andronesi7
    1Radiology, Massachusetts General Hospital, Charlestown, MA, United States, 2IBM Watson Health, Boston, MA, United States, 3Neurosurgery, Massachusetts General Hospital, Boston, MA, United States, 4Massachusetts General Hospital, Boston, MA, United States, 5Heidelberg University Hospital, Boston, MA, United States, 6Heidelberg University Hospital, Heidelberg, Germany, 7Massachusetts General Hospital,, Charlestown, MA, United States
    We developed deep learning super-resolution MR spectroscopic imaging (MRSI) to map tumor metabolism in patients with mutant IDH glioma. The preliminary results on simulated and in vivo data indicate that the proposed method is effective in enhancing the spatial resolution of metabolite maps.
    Fig.5: Upsampled HGG metabolic maps with size 184 x 184 using three measured patients data. From left to right (top), FLAIR, low-resolution (LR) HGG with size 46 x 46 after spectral quality (SQ) control, missing data filling in by inpainting (IPT) method and nonlocal means denoising (NLMD), super-resolution (SR) maps by Bicubic, weighted total variation (wTV), Unet and GAN. From left to right (bottom), LR HGG with size 46 x 46, LR HGG with size 46 x 46 after SQ control, missing data filling in by IPT method , SR maps by Bicubic+FNLM, wTV+FNLM, Unet+FNLM and GAN+FNLM.
    Fig.4: Upsampled total N-acetylaspartate (tNAA) maps with size 184x184 using three measured healthy subjects data. From left to right (top), high-resolution (HR) MEMPRAGE (MPRG), low-resolution (LR) tNAA with size 46 x 46 after spectral quality (SQ) control, missing data filling in by inpainting (IPT) method and nonlocal means denoising (NLMD), super-resolution (SR) maps by shown methods. From left to right (bottom), LR tNAA with size 46 x 46, LR tNAA with size 46 x 46 after SQ control, missing data filling in by IPT method , SR maps by shown methods.
  • Twofold Improved Tumor-to-Brain Contrast using a Novel T1 Relaxation-Enhanced Steady-State (T1RESS) Technique
    Robert R Edelman1,2, Nondas Leloudas3, Jianing Pang4, Julian Bailes5, Ryan Merrell6, and Ioannis Koktzoglou3,7
    1Radiology, NorthShore University HealthSystem, EVANSTON, IL, United States, 2Feinberg School of Medicine, Northwestern University, Chicago, IL, United States, 3Radiology, NorthShore University HealthSystem, Evanston, IL, United States, 4Siemens Medical Solutions USA, Chicago, IL, United States, 5Neurosurgery, NorthShore University HealthSystem, Evanston, IL, United States, 6Medicine, NorthShore University HealthSystem, Evanston, IL, United States, 7Pritzker School of Medicine, University of Chicago, Chicago, IL, United States
    We describe a novel class of steady-state pulse sequence called T1RESS that provides excellent SNR and contrast, as well as flexible control of intravascular signal.  For contrast-enhanced brain imaging, T1RESS demonstrated a remarkable two-fold improvement in tumor-to-brain contrast.
    Fig. 1. A) T1RESS pulse sequence using balanced (top) and unbalanced (bottom) steady-state readouts. A non-spatially selective contrast-modifying RF pulse (CMα) is applied periodically over the entire duration of the echo train to introduce an arbitrary amount of T1 weighting. B) Phantom consisting of serial dilutions of gadobutrol imaged with bT1RESS using CMα values of 0o, 30o and 60o. Note that there is negligible T1 contrast for a CMα flip angle of 0o, but substantial T1 contrast is apparent as the flip angle is increased to 60o.
    Fig. 2. Pulse sequence comparisons after contrast administration in a patient with metastatic melanoma. 10-mm thick axial (top) and coronal (bottom) maximum intensity projections are shown to highlight differences in lesion visibility for uT1RESS (left) and 3D spoiled GRE (right). Small metastatic lesions are much better visualized using uT1RESS than with 3D spoiled GRE. The combination of twofold increased tumor-to-background contrast, improved CNR and suppression of intravascular signals with uT1RESS is helpful to unambiguously identify small metastases.
  • Predictive Role of the ADC measurements and MRI Morphologic Features on Isocitrate Dehydrogenase Status in Patients with Diffuse Glioma.
    jun zhang1,2, Hong Peng1, Yu-Lin Wang1, De-Kang Zhang1, and Lin Ma1
    1Radiology, Chinese PLA general hospital, BeiJing, China, 2radiology, the sixth center of Chinese PLA general hospital, BeiJing, China
    In this study, using machine learning methods, the accurate prediction of IDH status was achieved for diffuse glioma via noninvasive MR imaging, including ADC values and tumor morphologic features, and it is worth mentioning ADC measurements applied are available in clinical workstations.
    Multivariable logistic regression analysis (including age, rADC and selected imaging features) was used to predict IDH status. (A) ROC curves of the multivariable probabilities for model 1 and model 2 show similar model performance in the study set. Model 1 consisted of rADC, age, enhancement pattern, calcification, cystic change and hemorrhage. Model 2 consisted of rADC, age, enhancement pattern, cystic change, hemorrhage and absence of calcification. (B) ROC curves of the multivariable probabilities for model 1 and model 2 show similar performance with the test set.
    Comparison of AUCs among machine learning models. Receiver operating characteristic curves shown for logistic regression (Log Reg), support vector machine (SVM), Naive Bayes (NB) and Ensemble (random forest + eXtreme Gradient Boosting) in predicting IDH status of glioma. Log Reg yielded the greatest AUC for single-model prediction.
  • Glioblastoma grading using perfusion parameters: comparing quantitative transport mapping method and kinetic modeling method
    Qihao Zhang1, Gloria Chia-Yi Chiang2, Thanh Nguyen2, Pascal Spincemaille2, and Yi Wang1
    1Cornell University, New York, NY, United States, 2Weill Cornell Medical College, New York, NY, United States
    QTM method can be applied to glioblastoma grading to eliminate the artery input function (AIF) dependency of kinetic modeling method.
    DCE MRI of a grade IV glioblastoma (figure a). (b) and (c) Ktrans and Ve using feeding artery of the tumor, respectively. (d) sampled AIF. (e) QTM velocity magnitude map. (f) and (g) Ktrans and Ve using carotid artery of the tumor, respectively. (h) sampled AIF.
    DCE MRI of a grade II glioblastoma (figure a). (b) and (c) Ktrans and Ve using feeding artery of the tumor, respectively. (d) sampled AIF. (e) QTM velocity magnitude map. (f) and (g) Ktrans and Ve using carotid artery of the tumor, respectively. (h) sampled AIF.
  • Strategy to overcome the spectral overlap between the 2-hydroxyglutarate and lipid resonances at 2.25 ppm
    Pegah Askari1, Ivan E Dimitrov1, Michael Levy1, Toral R Patel1, Edward Pan1, Bruce E Mickey1, Craig R Malloy1, Elizabeth A Maher1, and Changho Choi1
    1University of Texas Southwestern Medical Center, Dallas, TX, United States
    The lipid resonance at 2.25 ppm often complicates 1H MRS evaluation of 2HG. Incorporating new lipid basis sets in spectral fitting of 3T PRESS data from 43 glioma patients showed complete distinction between IDH mutation and wildtype (accuracy, sensitivity, and specificity all unity).
    FIG 4. (A,B) ROC analyses of the 2HG estimates from 43 patients are presented for Fitting methods 1 and 2. A red circle on an ROC curve corresponds to the smallest distance to the upper-left corner of the curve, at which a cutoff value was obtained as 1.3 and 0.8 mM for Fitting methods 1 and 2, respectively. (C,D) 2HG estimates from 24 IDH mutated and 19 IDH wildtype tumor patients are shown for Fitting methods 1 and 2. Green lines indicate the cutoff values from the ROC curves. For Fitting method 2, the 2HG estimates in IDH mutated tumors were 0.8 - 6.8 mM and those in IDH wildtype tumors were 0 - 0.4 mM.
    FIG 1. Representative in vivo PRESS TE 97 ms spectra from three glioma patients are presented with LCModel fitting outputs and voxel positioning on T2-FLAIR images. LCModel-returned 2HG signals are shown with 2HG estimates and CRLB in brackets. The LCModel built-in lipid basis set (Fitting method-1) included Lip09, Lip20, and Lip13. New lipid basis set (Fitting method-2) included LipNew1, LipNew2, and Lip13. Dotted lines denote exclusion of the lipid signals in the basis set. Spectra are scaled with respect to the water signal from the voxel. Vertical lines are drawn at 2.25 and 0.9 ppm.
  • Vascular input function measurement in brain tumor DCE-MRI: a comparison of arterial and venous sinus based approaches
    Xiaoping Zhu1, Daniel Lewis2, Ka-Loh Li1, Sha Zhao3, Timothy Cootes1, Andrew King2, David Coope2, and Alan Jackson3
    1DIIDS, University of Manchester, Manchester, United Kingdom, 2Neurosurgery, Salford Royal NHS Foundation Trust, Manchester, United Kingdom, 3University of Manchester, Manchester, United Kingdom
    In brain DCE-MRI the superior sagittal sinus can provide a superior global VIF compared to large intracranial arteries, demonstrating lower noise, higher bolus peak-amplitude and greater sensitivity to inter-individual changes in plasma contrast-agent concentration.
    Figure 2: Typical plasma contrast-agent concentration curves Cp(t) extracted from the horizontal segment of the middle cerebral artery (arrow head), MCA (A); vertical segment of the ICA (short arrow), carotid syphon (B); and vertical segment of the SSS (long arrow) (C) following a bolus injection of 0.023 mmol/kg of GBCA. The 1st-pass data are fitted using a gamma variate function, which excludes contrast-agent bolus recirculation. 3D T1-weighted gradient recalled echo mages obtained from a patient with a sporadic VS scanned at 1.5T.
    Figure 3: Relationship between extracted VIF features and administered GBCA dose for VIFSSS, VIFMCA and VIFICA. Top row: Scatter plots of VIF peak (mM/L) vs administered GBCA dose (mM/kg). Bottom row: Scatter plots of area (= peak∙FWHM: full-width at half-maximum, mM·s /L) of VIF vs administered GBCA dose.
  • Structural and Functional Changes in Patients with Lower Grade Tumors Receiving Partial Brain Radiotherapy: A Longitudinal Study
    Alan Finkelstein1, Arun Venkataraman2, Madalina Tivarus3, Md Nasir Uddin4, Jianhui Zhong1,2,3, Giovanni Schifitto3,4, Michael Milano5, Michelle Janelsins6, and Sara Hardy4,5
    1Biomedical Engineering, University of Rochester, Rochester, NY, United States, 2Physics and Astronomy, University of Rochester, Rochester, NY, United States, 3Imaging Sciences, University of Rochester, Rochester, NY, United States, 4Neurology, University of Rochester, Rochester, NY, United States, 5Radiation Oncology, University of Rochester, Rochester, NY, United States, 6Surgery, University of Rochester, Rochester, NY, United States
    Patients with lower grade tumors experience cognitive impairment in the setting of partial brain radiotherapy (RT). To understand what structures are susceptible to RT, structural and functional connectivity analysis were performed to evaluate how RT affects network topology. 
    Figure 1. Global graph theory metrics as a function of dose (EQD2) in Gy. A. Global efficiency and B. Transitivity reported as the percent change from baseline to 6 months. Solid lines are linear fits and shaded areas represent the 95% confidence interval. Pearson’s Correlation Coefficient
    Figure 2. Local graph theory metrics for subcortical regions. Percent change in A. Local efficiency and B. Clustering Coefficient as a function of EQD2 (Dose) in Gy. Solid lines are linear fits and shaded areas are the 95% confidence interval.
  • Contrast-enhanced T1-weighted DANTE-SPACE, PETRA, and MPRAGE: clinical evaluation comparison in intracranial tumor patients at 3T
    Qing Fu1,2, Qi-guang Cheng1,2, Xiao-yong Zhang3, Xiang-chuang Kong1,2, Ding-xi Liu1,2, Yi-hao Guo4, John Grinstead5, Zi-qiao Lei1,2, and Chuan-sheng Zheng1,2
    1Department of Radiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China, 2Hubei Province Key Laboratory of Molecular Imaging, Wuhan, China, 3Centers for Biomedical Engineering, University of Science and Technology of China, Hefei, China, 4MR Collaboration, Siemens Healthcare Ltd., Guangzhou, China, 5Siemens Medical Solutions USA, Inc., Portland, OR, United States
    Small cerebral metastases can be difficult to differentiate from blood vessels and surrounding parenchyma. Here we show that DANTE-SPACE outperforms both conventional MPRAGE and an advanced technique (PETRA) through blood vessel suppression.
    Figure 1. Representative images of MPRAGE (A, D), PETRA (B, E) and DANTE-SPACE (C, F) of a 57-year-old male with cerebral metastases of lung cancer. A-C: a well-enhanced lesion (arrowheads) near the cerebral falx in the right frontal lobe is seen in all sequences. The lesion is more conspicuous with DANTE-SPACE due to blood vessel suppression and high CNR, and could have been mislabeled as a small vessel with MPRAGE and PETRA. D-F: a small homogeneously meningioma in the left temporal lobe was displayed clearly in all sequences with clear margin
    Figure 2. Post-contrast T1-weighted images of an enhancing tumor in right temporal lobe in a 37-year-old female. The signal intensity within this tumor was relatively homogeneous in MPRAGE (A) and PETRA (B), but it was heterogeneous in DANTE-SPACE (C). The enhancing effect (arrows) of adjacent meninges is more continuous in PETRA. The tumor signal from DANTE-SPACE (C) closely resembles pre-contrast T1WI and T2WI (G, H), and it was identified as a myopericytoma by surgical pathology (I).
  • Evaluation of Ultrafast Post-Contrast Wave-CAIPI 3D-T1 MPRAGE Compared to Standard 3D-T1 MPRAGE for Evaluating Enhancing Lesions on 3T MRI.
    Augusto Lio M. Goncalves Filho1,2, John Conklin1,2, Chanon Ngamsombat3, Stephen F. Cauley2, Wei Liu4, Daniel N. Splitthoff5, Wei-Ching Lo6, John E. Kirsch1, Pamela W. Schaefer1, Otto Rapalino1, and Susie Y. Huang1,2
    1Department of Radiology, Massachusetts General Hospital, Boston, MA, United States, 2Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, MA, United States, 3Department of Radiology, Siriraj Hospital, Bangkok, Thailand, 4Siemens Shenzhen Magnetic Resonance Ltd., Shenzhen, China, 5Siemens Healthcare GmbH, Erlangen, Germany, 6Siemens Medical Solutions Inc., Boston, MA, United States
    An accelerated post-contrast Wave-CAIPI 3D T1 MPRAGE sequence is non-inferior to the standard T1 MPRAGE for detection of intracranial enhancing lesions in 3T MRI while providing a 2-fold reduction in acquisition time and being less sensitive to motion artifacts.
    Figure 2. Representative images showing a comparison of post-contrast Wave-CAIPI T1 MPRAGE and standard T1 MPRAGE sequences. (A) A 56-year-old male with brain metastases from squamous-cell carcinoma. (B) A 71-year-old male with brain metastases from non-small cell lung cancer.
    Figure 1. Balloon plot showing the results of the head-to-head comparison of post-contrast standard T1 MPRAGE and post-contrast Wave-CAIPI T1 MPRAGE for visualization of abnormal intracranial enhancing lesions, the perception of noise, presence of artifacts due to motion, and the overall diagnostic quality. A zero-score indicates equivalency, negative scores (left) favor standard T1 MPRAGE, and positive scores (right) favor Wave-T1 MPRAGE.
  • DiffusionGo: A fully automatic fiber tracking software for neurosurgeon
    Shin Tai Chong1, Jianping Song2, Kuan-Tsen Kuo3, Yu-Ting Ko3, Sanford PC Hsu4, Jinsong Wu2, and Ching-Po Lin1
    1Institute of Neuroscience, National Yang-Ming University, Taipei, Taiwan, 2Department of Neurosurgery, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China, 3ABC Solution Co., Ltd, Shanghai, China, 4Department of Neurosurgery, Neurological Institute, Taipei Veterans General Hospital, Taipei, Taiwan
    DiffusionGo is an in-house developed software specially designed for neurosurgeons, which integrated a reliable pre-processing pipeline, fully automatically fiber reconstruction algorithm, and multimodalities imaging information to achieve easy modeling and precision surgery. 
    Multimodalities integration in a 60-year-old male with left frontal bAVM in DiffusionGo. S1 and S2 Speech arrest was defined as discontinuation in number counting without simultaneous motor response by DCS (a). AF (red), SLF II (green), and posterior segment of SLF (yellow) were automatically reconstructed (d). Comparing with language BOLD functional activation (c), Tract-based cortical termination (AF termination in red; SLF II termination in green; orange color represented the overlap of AF and SLF II) has more sensitivity to manifest with DCS results (e).
    A 41-year-old female with temporal lobe glioblastoma was reconstructed and displayed in DiffusionGo. Cortical surface (white), blood vessel (gold), tumor (green), and peritumoral edema (light blue with translucent) were integrated (a). The lateral view and superior view of the tumor, dorsal language pathway (AF, red; SLF II, green), and ventral language pathway (IFL, light blue; IFOF, light green; UF, pink). The termination projection of AF was shown in d. Superior displacement of left Wernicke’s area was identified with intact AF projecting to left premotor and left Broca areas.
  • The combined value of DKI and DSC MRI in differentiating high-grade glioma recurrence from pseudoprogression
    Yan Tan1, Wenwei Shi2, Xiaochun Wang1, and Hui Zhang1
    1Department of Radiology, First Hospital of Shanxi Medical University, Taiyuan, China, 2Department of Radiology, Zhongda Hospital, Southeast University, Nanjing, China
    rMK can differentiate recurrent tumor from pseudoprogression with high diagnostic accuracy, and its application value is similar to that of rCBV. The combination of rMK and rCBV improves diagnostic performance compared to either technique alone.
    ROC curves of DKI and DSC MRI parameters for differentiating glioma recurrence from pseudoprogression.
    A 21-year-old man with tumor recurrence confirmed by repeat surgery was initially a high-grade glioma (WHO IV). An increasing enhanced lesion in the right frontal and temporal lobes was detected on CE-T1WI with increased CBV, CBF, MTT, TTP, MK, Ka and Kr values, except for MD and FA values.
  • Development of MR Elastography Methods for Assessing Adhesion Between Pituitary Masses and the Optic Chiasm
    Yi Sui1, Myung-Ho In1, Salomon Cohen-Cohen2, Erin Gray1, Kevin Glaser1, Matt A. Bernstein1, Jamie J Van Gompel2, Richard L. Ehman1, John Huston III1, and Ziying Yin1
    1Radiology, Mayo Clinic, Rochester, MN, United States, 2Neurologic Surgery, Mayo Clinic, Rochester, MN, United States
    A distortion-free EPI-MRE technique was developed to acquire  ~1mm high resolution NOSS map for assessing adhesion between pituitary adenoma and adjacent optic chiasm.
    Figure 1: Distortion-free EPI-MRE magnitude, NOSS map, and MP-RAGE image from a pituitary adenoma patient.
  • Conventional MRI Texture Analysis to Predict Proliferative Behaviour in Gliomas
    Xiaoxin Li1, Qingwei Song1, Ailian Liu1, Lizhi Xie2, and Yanwei Miao1
    1First Affiliated Hospital of Dalian Medical University, Dalian, China, 2GE Healthcare, MR Research China, Beijing, China
    To evaluate the application value of texture analysis based on conventional MRI for predicting the cell proliferation status of glioma.
    ROC curves showed that the AUC of uniformity (0.818) and correlation (0.711) in contrasted T1WI were greater than the other features among three sequences, so uniformity and correlation showed better diagnostic efficiency for predicting the proliferation status glioma.
  • Value of Diffusion Kurtosis Imaging in Detecting Isocitrate Dehydrogenase Genotype in Low-grade Gliomas
    Tao Gong1, Liangjie Lin2, and Yihang Yang3
    1Shandong Medical Imaging Research Institute, Jinan, China, 2Philips Healthcare, Beijing, China, 3Shandong provincal hospital, Jinan, China
    IDH 1 wild-type gliomas have higher MK and lower MD values in tumor foci compared with IHD 1 mutant gliomas. Lower FA in perilesional white matter was seen in wild-type gliomas, while no difference was found in mutant patients, suggesting greater infiltrative nature in IDH 1 wild-type gliomas.
    Figure 1. MD (A), MK (B) and FA color (C) maps in a 35-year-old man with IDH 1-mutated glioma (WHO II); and MD (E), MK (F) and FA color (G) maps in a 36-year-old woman with IDH 1 wild-type glioma (WHO II); ROIs of glioma foci, pWM and cNAWM were drawn on non-smoothed MD maps (D and H). MD = mean diffusion; MK = mean kurtosis; FA = fractional anisotropy; pWM = perilesional white matter; cNAWM = contralateral normal appearing white matter; ROI = region of interest.
    Figure 3. ROC curves of MK and MD values calculated from the glioma foci for differentiating IDH 1 mutant and wild-type low-grade gliomas. The AUC of MK was 0.88 (95% CI, 0.74~1.00), MD was 0.86 (95%CI, 0.73~0.99). MK = mean kurtosis; MD = mean diffusion.
  • Simultaneously acquired PET and ASL imaging biomarkers are helpful in differentiating progression from pseudo-progression in treated gliomas
    Nadya Pyatigorskaya1,2,3, Arnaud Pellerin1, Maya Kalife4, Marc Bertaux5, Marine Soret5, Didier Dormont1, and Aurélie Kas5
    1Neuroradiology, Pitié-Salpêtrière Hospital, APHP, Sorbonne universite, Paris, France, 2UMR S 1127, CNRS UMR 722, ICM, Sorbonne Universités, Paris, France, 3CENIR, ICM, Sorbonne Universités, Paris, France, 4CENIR, ICM, Paris, France, 5Nuclear Medecine, Pitié-Salpêtrière Hospital, APHP, Sorbonne universite, Paris, France
    We aimed at investigating the methods based on coupling cerebral perfusion and amino-acid metabolism measurements to evaluate the PET/MRI in glioma follow-up. The tumour isocontour maps and T-maps showed the highest specificity and sensitivity for ASL and 18F-DOPA analysis.

    PET-MR of a patient with left WHO IV glioblastoma treated by surgery and adjuvant radio-chemotherapy.

    Upper row: A: enhancement on the frontal lesion on a contrast-enhanced axial T1-w image; B: hyper-perfusion with increased CBF on ASL images corresponds to the area of contrast enhancement; C: 18F-DOPA PET map with increased SUV

    Lower row: SPM maps were concordant with significant clusters, which confirmed progression. The red ASL clusters appear to be more peripheral than the blue extensive PET clusters. D: T-score map; E: Z-score of asymmetry index; F: isocontour map.

    PET-MR of patient with right glioblastoma, treated by surgery and adjuvant radiotherapy

    Upper row: A: linear cavitary enhancement observed on the initially-treated frontal lesion site on a contrast-enhanced axial T1-w image; B: the absence of hyper-perfusion as assessed by CBF on ASL images; C: 18F-DOPA PET map showing no significantly increased SUV

    Lower row: SPM maps were concordant, with the absence of significant clusters, which confirmed pseudo-progression. D: T-score map; E: Z-score of asymmetry index; F: isocontour map.

  • Applying 2HG MRS in glioma patients during routine clinical MRI examination
    Zahra Shams1, Sarah M. Jacobs1, Jan W. Dankbaar1, Changho Choi2, Dennis W.J. Klomp1, Jannie P. Wijnen1, and Evita C. Wiegers1
    1Department of Radiology, University Medical Center Utrecht, Utrecht, Netherlands, 2Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX, United States
    We implemented 2HG MR spectroscopy in the clinical routine of the glioma patients. We showed technical feasibility, the success rate and robustness of the protocol.
    Figure 1. Evaluation of the spectra based on quality and reliability of the 2HG fit. Examples of each group have been shown in (B).
    Figure 3. The relationship between 2HG concentration and the concentration of Glu+Gln and GABA in ‘Questionable’ (A) and ‘Reliable’ (B) fits. ×: information on voxel location in the tumor tissue is not available. Small marker size: no tumor (likelihood of 0-25%); big marker size: tumor (likelihood of 50-100%).
  • High dual-contrast putamen MRI at 1.5T: Application to intraoperative MRI during neurosurgical procedure
    Chan Hong Moon1, Krystof Bankiewicz2, Paul Larson2, Adrian Kells3, Alastair J. Martin2, Stephen Mancuso4, and Mark Richardson5
    1University of Pittsburgh, Pittsburgh, PA, United States, 2University of California San Francisco, San Francisco, CA, United States, 3Voyager Therapeutics Inc., Cambridge, MA, United States, 4UPMC, Pittsburgh, PA, United States, 5Massachusetts General Hospital, Boston, MA, United States
    In this study, we developed new dual-contrast MPRAGE and maximized T1 contrast in putamen as well as good anatomy of whole brain without additional acquisition compared to conventional MPRAGE. The proposed methods were applied to 1.5T iMRI during neurosurgical procedure of PD patients.
    Fig. 3 T1 anatomy MRI; (from left) Pre-surgical @3T, Post contrast at1.5T (MPRAGE, dual T1 MPRAGEs) and AADC infusion at1.5T (MPRAGE, dual T1 MPRAGEs). Note that new dual T1 MPRAGE at1.5T can provide higher contrast of Put than that at 3T. In addition, dual T1 MPRAGE provides good whole brain anatomy. White spots are the targeted infusion regions.
    Fig. 2 3D MPRAFGE MR images at effective TI 330 (A and A’), 350 (B), 370 (C) and 880 msec (D) at kz = 0; only axial images are shown. The images in A and A’ were acquired at a week apart sessions. Black arrows indicate the aliasing artifact in conventional MPRAGE image. Note that the signal in the white mater at optimal TI ~330 msec is well suppressed and the contrast of putamen (white arrowhead) and glubus pallidus (black arrowhead) vs. white mater is much higher than those of conventional MPRAGE image at effective TI 880 msec. In addition, the optimal TI MPRAGE MRI is reproducible.
  • Detection of Cystathionine, 2-Hydroxyglutarate and Citrate in Oligodendrogliomas at 7T using Long-TE Semi-LASER
    Uzay E Emir1,2, Natalie E Voets3, Sarah E Larkin4, Nick De Pennington4, Puneet E Plaha4, Richard E Stacey4, James E Mccullagh4, Christopher J Schofield4, Stuart E Clare3, Peter Jezzard3, Thomas Cadoux-hudson4, and Olaf E Ansorge4
    1School of Health Sciences, Purdue University, West Lafayette, IN, United States, 2Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, United States, 3Wellcome Centre for Integrative Neuroimaging, Nuffield Dept of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom, 4University of Oxford, Oxford, United Kingdom
    We demonstrate that long-TE semi-LASEr at 7 Tesla has the potential to allow presurgical stratification of patients with IDH-mutant glioma into those with oligodendrogliomas and astrocytomas; which is of important prognostic significance.
    LCModel analysis of an IDH mutant glioma patient's spectrum with and without cystathionine in the basis set
    Metabolite ratios of cystathionine over total choline in codeleted and no-codeleted gliomas
  • Dose Painting Intensity-modulated Radiotherapy Guided by 3D arterial spin labeling MRI for Brain Metastases
    Chuanke Hou1, Guanzhong Gong1, Weiqiang Dou2, and Yong Yin1
    1Department of Radiation Physics, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, China, 2GE Healthcare, MR Research China, Beijing, China
    3D-Araterial Spine Labeling can be used to segment high and low cerebral blood flow sub-volumes. Then the plan with maximum dose constraint performed better for dose escalation in low cerebral blood flow (hypoxic) sub-volumes  without increasing the dose delivered to organs at risk. 
    Figure1 Different tumor information was shown between contrast-enhanced T1W images and 3D-ASL images. A: contrast-enhanced T1W images; B:3D-ASL; C: 3D-ASL fusion registration to contrast-enhanced T1W images.According to the enhanced area shown in the figure A, figure B showed the uneven distribution of CBF in tumor. The high cerebral blood flow area was mainly located on the right side of the enhanced edge, while the low cerebral blood flow area and the enhanced area overlap in a large region. Moreover, the fusion image C showed this result more clearly.
    Table 1 The Characteristics of 50 single BM patients
  • Multi-parametric MRI in differentiation between brain tumor and radiation necrosis
    Sean P Devan1, Xiaoyu Jiang1, Guozhen Luo2, Jingping Xie1, Zhongliang Zu1, Ashley M Stokes3, Austin N Kirschner2, John C Gore1, and Junzhong Xu1
    1Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, United States, 2Radiation Oncology, Vanderbilt University Medical Center, Nashville, TN, United States, 3Keller Center for Imaging Innovation, Barrow Neurological Institute, Phoenix, AZ, United States
    Six MRI methods were performed and compared to differentiate between normal appearing brain tissues, 9L gliosarcoma brain tumors, and radiation necrosis in animal models. APT and SSIFT provide the best discrimination of different tissue types. 
    Representative multi-parametric maps of two rat brains with an RN in the left hemisphere (top) and a 9L tumor in the right hemisphere (bottom).
    Summarized ROI-based MRI parameters in the differentiation of contralateral normal appearing brain tissue (n=9), radiation necrosis (RN, n=5), and 9L brain tumor (n=4).
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Digital Poster Session - Head, Neck & Other Brain Tumor
Neuro
Thursday, 20 May 2021 15:00 - 16:00
  • The visualization of the saccule and utricle with non-contrast-enhanced FLAIR sequence.
    Hikaru Fukutomi1, Xavier Barreau2, Lydia Hamitouche2, Takayuki Yamamoto1, Laurent Denat1, Bei Zhang3, Lijun Zhang4, Bruno Triaire5, Valentin Prevost5, Vincent Dousset1,2, and Thomas Tourdias1,2
    1Institut de Bio-imagerie IBIO, Université de Bordeaux, Bordeaux, France, 2CHU de Bordeaux, Neuroimagerie diagnostique et thérapeutique, Bordeaux, France, 3Canon Medical Systems Europe, Zoetermeer, Netherlands, 4Canon Medical Systems China, Beijing, China, 5Canon Medical Systems Corporation, Tochigi, Japan
    For inner ear exploration, combining specific T2 preparation and inversion time on non-injected 3D-FLAIR provided a high contrast between peri- and endo-lymphatic spaces and even allows delineating the saccule from the utricle.
    Figure 4. Non-contrast FLAIR images with T2Prep 400ms and TI 2100ms of a representative healthy subject. a, b Axial slice through the inferior part of the vestibule. c, d Sagittal reference slice. The saccule and utricle are separately visualized. Delineation of two structures is very similar to what is observed with contrast-enhanced FLAIR images in the literature (Attyé et al3). PSC posterior semicircular canal, LSC lateral semicircular canal, SSC superior semicircular canal, white arrow cochlea, dotted white arrow vestibule.
    Figure 3. Peri- and endo-lymphatic space signal curves with variable TIs (224-5000ms) and T2Prep (0-600ms). Error bars indicate standard errors. a, b Red lines show the differences of the null points, which is larger when using 400ms T2Prep than 200ms. Green lines show the signal difference of peri- and endolymphatic spaces at endolymphatic space’s null point. The relative contrast of the two space was larger when using 400ms T2Prep than 200ms.
  • Negative-contrast neurography of the extracranial facial nerve and branches based on variable flip angle turbo spin echo imaging
    Timothy Bray1,2, Alan Bainbridge1,3, Susan Jawad2, Sofia Otero2, Timothy J Beale2, Sumandeep Kaur2, Mark McGurk4, Margaret A Hall-Craggs1,2, and Simon Morley2
    1Centre for Medical Imaging, University College London, London, United Kingdom, 2Department of Imaging, University College London Hospital, London, United Kingdom, 3Medical Physics, University College London Hospital, London, United Kingdom, 4Head and Neck Academic Centre, University College London, London, United Kingdom
    An approach to 'neurographic' imaging of the extracranial facial nerve at high resolution using variable flip angle turbo spin echo imaging is proposed. This method depicts the nerve as a low-signal structure (‘black nerve’) against the high-signal parotid parenchyma (‘white parotid’).
    Figure 2: Example images. Methods 1, 2 and 3 are shown in (a), (b) and (c) respectively. An example of a segmentation mask is shown in (d): the main trunk is segmented in red, the upper division in green and the lower division in blue.
    Figure 1: MRI sequences and acquisition parameters.
  • Differentiation of benign and malignant neck tumors by APT
    Xiaohan Song1, Lijun Wang1, Ailian Liu1, Jiazheng Wang1, and Lihua Chen1
    1the First Affiliated Hospital of Dalian Medical University, Dalian, China

     Our results suggested the potential of APTw imaging in the differential diagnosis between malignant and benign neck tumors with relatively high sensitivity and specificity.

     

    Figure2 : APTw values of the cervical malignant tumor group were significantly higher than those of the benign tumor group

    Figure3: The ROC curve of the APTw value to differentiate between the malignant and benign neck tumors.
  • 3D bSSFP Imaging performance using high performance gradients at 0.5T is comparable to standard field strengths: Clinical use in Temporal Bone MRI
    David Volders1, James Rioux1, Steven Beyea1, Chris V Bowen2, and Elena Adela Cora1
    1Diagnostic Radiology, Nova Scotia Health, Halifax, NS, Canada, 2Diagnostic Imaging, Nova Scotia Health, Halifax, NS, Canada
    Evaluation of temporal bone MRI scans using a 0.5T high performance gradient head only system reveals high quality visualization of clinically relevant structures using 3D bSSFP imaging.
    Figure 1: Representative cross-sectional 3D bSSFP images for a patient at 0.5T (a) and 3T (b) reformatted into various labeled planes (i.-iv.). Key anatomical structures being rated by 2 board certified radiologists are shown. Blue arrow: superior semicircular canal; Yellow arrow: facial (top) and cochear (bottom) nerve; White arrow: superior vestibular (top) and inferior vestibular (bottom) nerve; Green arrow: vestibule; Red arrow: cochlea.
    Table 1: Statistical comparison of 0.5T vs clinical field strength scans
  • Childhood Brain Tumour Classification Through Proton Magnetic Resonance Spectroscopy and Diffusion Weighted Imaging
    Dadi Zhao1,2, James T. Grist1,2, Heather E.L. Rose1,2, Huijun Li2, Lesley MacPherson2, Yu Sun1,2, and Andrew C. Peet1,2
    1Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, United Kingdom, 2Department of Oncology, Birmingham Children's Hospital, Birmingham, United Kingdom
    Multi-modal functional imaging provides improved classification performance for childhood brain tumours. The combination of diffusion weighted imaging and noise-suppressed proton magnetic resonance spectroscopy shows promising for classifying imbalance childhood brain tumours.
    Images showing the acquired b0 (A), b1000 (B) and apparent diffusion coefficient (C) images with the region of interest for brain tumour as well as the noisy (D) and noise-suppressed (E) proton magnetic resonance spectroscopy of a patient with a medulloblastoma.

    Boxplots comparing the balanced classification accuracy estimated through leave-one-out (A-B) or six-fold (C-D) cross validation and determined through linear discriminant analysis (A, C) or support vector machine (B, D) from diffusion weighted imaging (DWI) only, noise-suppressed proton magnetic resonance spectroscopy (NS-MRS) only, or combining NS-MRS and DWI.

    Levels of significance: *, P<.05; **, P<.01; ***, P<.001; ****, P<.0001.

  • Multiparametric Physiologic MR Imaging of Head and Neck Cancer: Imaging Biomarker for Tumor Hypoxia and Heterogeneity
    Yoshimi Anzai1, John A Roberts2, Seong-Eun Kim2, Ying Hitchcock3, Richard Wiggins1, Nousheen Alasti2, and Eugene Kholmovski2
    1Department of Radiology and Imaging Sciences, University of Utah, Salt Lake City, UT, United States, 2UCAIR, Department of Radiology and Imaging Sciences, University of Utah, Salt Lake City, UT, United States, 3Radiation oncology, University of Utah, Salt Lake City, UT, United States

    A composite color map combining quantitative information from multiparametric imaging (oxygen-enhanced BOLD, DWI, and FDG-PET) has the potential to reveal the spatial distribution of the area of hypoxia within a tumor.

     

    Fig 3. The color map of the patient (a, b) shows a green color of the base of tongue tumor and right lymph node metastases suggestive of low ADC value with non-zero ΔR2*, oxygenated tumor. The color map of another patient (c, d) of right tonsillar carcinoma shows pink-magenta color posteriorly, suggestive of near-zero ΔR2* and high PET activity, features of hypoxic tumor. This patient had early recurrence and disease-related mortality

    Fig 2. 2D scatter histograms comparing (a) ADC to DR2*, (b) FDG-PET to ΔR2*, and (c) FDG-PET to ADC. A large standard deviation (length of vertical and horizontal bars) and ΔR2* are observed in a patient with recurrence (subject 6).
  • Clinical utility of turbo gradient and spin echo BLADE-DWI (TGSE-BLADE-DWI) for orbital tumors compared with readout-segmented echo-planar DWI
    Qing Fu1,2, Xiang-chuang Kong1,2, Ding-xi Liu1,2, Yi-hao Guo3, Kun Zhou4, Zi-qiao Lei1,2, and Chuan-sheng Zheng1,2
    1Department of Radiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China, 2Hubei Province Key Laboratory of Molecular Imaging, Wuhan 430022, China, Wuhan, China, 3MR Collaboration, Siemens Healthcare Ltd., Guangzhou, China., Guangzhou, China, 4Siemens Shenzhen Magnetic Resonance Ltd., Shenzhen, China., Shenzhen, China
    2D turbo gradient and spin echo BLADE-DWI was superior to readout-segmented echo-planar-DWI in depicting orbital tumors with reduced susceptibility artifacts.
    Figure 1. T2-weighted imaging (T2WI), b0 images of 2D TGSE-BLADE-DWI, and RESOLVE-DWI were fused. Color- and gray-coated images were derived from the T2WI and the two DWI b0 images, respectively. The T2WI and TGSE-BLADE-DWI b0 images matched well, showing the left orbital tumor (long arrows), ethmoid and maxillary sinuses (short arrows). The T2WI and RESOLVE-DWI b0 images were mismatched due to geometric distortions.
    Figure 2. A 50-year-old male with a left orbital tumor. Compared with the T2-weighted imaging (T2WI) images and contrast-enhanced T1WI images, this lesion could be visualized clearly with TGSE-BLADE-DWI; no geometric distortions were seen. Slight distortions were seen with RESOLVE-DWI. More geometric distortions and ghosting artifacts were observed in the frontal lobe and ethmoid sinus with RESOLVE-DWI.
  • The efficacy 2D turbo gradient- and spin-echo diffusion-weighted imaging for cerebellopontine angle tumors
    Qing Fu1,2, Xiang-chuang Kong1,2, Ding-xi Liu1,2, Yi-hao Guo3, Kun Zhou4, Zi-qiao Lei1,2, and Chuan-sheng Zheng1,2
    1Department of Radiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China, 2Hubei Province Key Laboratory of Molecular Imaging, Wuhan 430022, China, Wuhan, China, 3MR Collaboration, Siemens Healthcare Ltd., Guangzhou, China., Guangzhou, China, 4Siemens Shenzhen Magnetic Resonance Ltd., Shenzhen, China., Shenzhen, China
      2D turbo gradient- and spin-echo-BLADE diffusion-weighted imaging (DWI) was found to be superior to readout-segmented echo-planar-DWI and single-shot echo-planar-DWI in depicting and diagnosing cerebellopontine angle tumors.
    Figure 1. A 50-year-old female with a left internal auditory canal acoustic neuroma (red arrows). The lesion is clearly visible on the TGSE-BLADE-DWI scans without geometric distortion, but with moderate and severe distortions on the RESOLVE-DWI and SS-EPI-DWI scans, respectively, interfering with lesion detection. Ghosting artifacts (white arrows) were absent at bone-air interfaces and anatomic structural identifications (blue arrows) were superior on the TGSE-BLADE-DWI scans compared with the other two DWI methods.
    Table 3. A comparison of the subjective evaluation results among the three diffusion-weighted imaging methods.
  • Improved visualization of optic nerve DWI using IRIS: comparison with conventional methods
    Yutaka Hamatani1, Kayoko Abe2, Masami Yoneyama3, Jaladhar Neelavalli4, Yasuhiro Goto1, Isao Shiina1, Kazuo Kodaira1, Takumi Ogawa1, Mamoru Takeyama1, Isao Tanaka1, and Shuji Sakai2
    1Department of Radioligical Services, Tokyo Women's Medical University Hospital, Tokyo, Japan, 2Department of Diagnostic imaging & Nuclear Medicine, Tokyo Women's Medical University Hospital, Tokyo, Japan, 3Philips Japan, Tokyo, Japan, 4Philips Healthcare, Bangalore, India
    IRIS (Image Reconstruction using Image-space Sampling Function) is one of multi shot echo planar EPI-DWIs combined with phase correction, and it was the best sequence to visualize the optic nerve, compared other conventional DWI techniques.
    Figure 1.The IRIS sequence chart. IRIS adopts multi shot acquisition which signal collection into k-space is divided in the phase direction. Multi shot acquisition tends to cause ghost artifacts, so IRIS applies navigator-echo for each shot to make phase corrections.
    Figure 2. DWI of the optic nerve on SSh EPI-DWI, SSh TSE-DWI, MSh. TSE-DWI, and IRIS. IRIS shows the least artifacts and image distortion, and the optic nerve was demonstrated with the highest image contrast on IRIS.
  • Compressed Sensing vs. Conventional Parallel Imaging: Utility of Head and Neck MRI for Image Quality and Inspection Efficacy
    Hirotaka Ikeda1, Yoshiharu Ohno1, Kaori Yamamoto2, Kazuhiro Murayama3, Masato Ikedo2, Masao Yui2, Satomu Hanamatsu1, Akiyoshi Iwase4, Takashi Fukuba4, and Hiroshi Toyama1
    1Radiology, Fujita Health University School of Medicine, Toyoake, Japan, 2Canon Medical System Corporation, Otawara, Japan, 3Joint Research Laboratory of Advanced Medical Imaging, Fujita Health University School of Medicine, Toyoake, Japan, 4Fujita Health University Hospital, Toyoake, Japan
    CS with PI has better capability than conventional PI for improving head and neck MR imaging with a shorter examination time and quantitatively better image quality and without any significant deterioration of qualitative image quality.

    Figure1. 21-year-old male with lymphatic malformation (L to R: cranial to caudal level).

    T2-weighted images obtained with CS with PI and with conventional PI clearly demonstrate the multiple cystic lesions extending from parotid space to parapharyngeal space (arrows). Neither image showed significant artifacts and both had the same overall image quality. The examination time of CS with PI (76 sec) was much shorter than that of conventional PI (126 sec).

    Figure 2. Results of comparison for each quantitative image quality index among CS with PI and conventional PI.

    SNR of CS with PI (11.2±3.6, mean ± standard deviation) was significantly higher than that of conventional PI (8.9±2.6, p<0.0001). %CV of CS with PI (9.6±3.0) was significantly lower than that of conventional PI (11.9±3.5, p<0.0001). CNR of CS with PI (7.7±2.9) was significantly higher than that of conventional PI (6.1±2.2, p<0.0001).

  • Can texture analysis of T2WI be used to predict extrathyroidal extension in papillary thyroid carcinoma?
    Heng Zhang1, Shudong Hu1, Weiqiang Dou2, and Weiyin Vivian Liu2
    1Department of Radiology, Affiliated Hospital, Jiangnan University, Wuxi, China, 2GE Healthcare, MR Research, Bejing, China
    76 patients with pathologically confirmed papillary thyroid carcinoma (PTC) underwent preoperative thyroid T2-weighted (T2WI) MRI examination in this retrospective study. Using texture analysis for acquired T2WI imaging, entropy was found significantly higher in PTC patients with extrathyroidal extension (ETE) than without ETE, and thus considered an independent index for predicting PTC patients with ETE. With this finding, we therefore consider that preoperative T2WI-based texture features may be valuable for identifying ETE status in PTC patients and may help customize treatment strategies.
    Figure 1 A ROI segmentation in a randomly selected case based on sagittal transverse T2WI. (A) Images from a representative PTC patient without ETE (female, 47 years old). (B) Images from a representative PTC patient with ETE (female, 37 years old).
    Table 3 Multivariate logistic regression analysis results
  • The clinical value of magnetic resonance imaging in patients with sudden hearing loss for pathogenic diagnosis and prognostic evaluation
    Yanjun Wang1, Shenghong Ju1, Jilei Zhang2, and Yuancheng Wang1
    1Radiology, Zhongda Hospital, School of Medicine, Southeast University, Nanjing, China, 2Philips Healthcare, Greater China, Shanghai, China
    The proposed 3D-FLAIR MR protocol is useful for pathogenic diagnosis and positive 3D-FLAIR findings with SIRs measurement can reflect the severity of initial hearing loss. The combination of clinical and MR features is beneficial for the prognostic evaluation of unilateral SSNHL. 

    A 43ys patient presenting with SSNHL and tinnitus of the left ear for 7 days. The PTA was 80 dB. 3D-FLAIR images was scanned 3 days later, showed that SIs of the left cochlea and vestibule were slightly higher than those of the right with markedly delayed enhancement after contrast. Other sequences showed no abnormality. This case was diagnosed as unilateral SSNHL due to labyrinthine inflammation combined with blood labyrinth barrier disruption. The patient was hospitalized and received a comprehensive therapeutic protocol for 9 days, the curative effect was ineffective as expected.

    ROC curves of the two primary clinical-image prognosis assessment models for unilateral SSNHL.

    Fig a. Model used for no hearing recovery with a moderate prediction value. It included six prognostic factors: age ≥ 50 years, simultaneously abnormal DPOAE and TEOAE, longer period from onset to clinical examination, PTA at onset, severe to profound initial hearing loss, and positive MR inner ear findings. Fig b. Model used for complete hearing recovery with a high prediction value. It consisted of two prognostic factors: PTA at onset and the period from onset to MR examination.

  • Development and optimization of diffusion-weighted imaging protocols for the optic nerve and pituitary gland
    Zhiqiang Li1, Sharmeen Maze1, and John P Karis1
    1Neuroradiology, Barrow Neurological Institute, Phoenix, AZ, United States
    DWI of the optic nerve and pituitary gland is difficult with EPI. msEPI and distortion free SPLICE PROPELLER have recently been released to the clinic. This work develops DWI protocols for the optic nerve and pituitary gland. Good image quality with clinically sound scan time is achieved.
    Fig. 3. Volunteer images acquired using the proposed SPLICE-PROPELLER protocols demonstrate good image quality without distortion artifacts.
    Fig. 4. Patient results of the pituitary gland with the proposed SPLICE-PROPELLER protocol. Clear delineation of the pituitary gland with consistent quality is achieved in the clinical settings.
  • Application of Compressed Sensing Technology in the Fast Spin Echo Diffusion Weighted Imaging of the Skull Base
    Haonan Zhang1, Qingwei Song1, Jiazheng Zhang2, Yishi Wang2, Renwang Pu1, Nan Zhang1, and Ailian Liu1
    1Department of Radiology, the First Affiliated Hospital of Dalian Medical University, Dalian, China, 2PHILIPS——Philips Healthcare, beijing, China
    In this study, we demonstrated that a large CS acceleration factor will degrade the image quality of TSE-DWI for skull base significantly. CS factor of 5.6 is recommended for the trade-off between the scan time and image quality of TSE-DWI for the skull base.
    Figure 1. The first row, from left to right: Group B EPI, SENSE2.6, CS2.6-CS7.6. The second row, from left to right: Group C EPI, SENSE2.6, CS2.6-CS7.6
    Figure2.ROIs for measurements of ADC. The measured left and right ADC was 0.81×10-3 and 0.69×10-3, respectively. The ADC value of the lesion is 0.47×10-3.
  • The Value of Apparent Diffusion Coefficient Gray Histogram in the Differential Diagnosis of Central Nervous System Lymphoma
    Zhen MA1, Xin ZHAO1, Kaiyu Wang2, and Jinxia Guo3
    1The Third Affiliated Hospital of Zhengzhou University, Zhengzhou City, China, 2GE Healthcare, MR Research China,, Beijing, China, 3GE Healthcare, MR Research China, Beijing, China
    Retrospective analysis of patients with brain MRI examination and confirmed by pathology, respectively in three groups of MR ADC axial images, using Mazda software to delineate the region of interest at each level of the tumor, and carry out gray-scale global histogram analysis, and statistical analysis of the three groups of histogram parameter characteristics.The nine parameters, mean, variance, kurtosis, skewness, perc. 01%, perc. 10%, perc. 50%, perc. 90% and perc. 99% were obtained by gray histogram analysis (P < 0.05). 

    Fig. 3 A ROC curve was made based on the six most statistically significant parameters for differentiating glioblastoma and CNS lymphoma.

    An ROC curve was made based on the six most statistically significant parameters for differentiating glioblastoma and metastatic tumors.

    An ROC curve was made based on the six most statistically significant parameters for differentiating CNS lymphoma and metastatic tumors.

    Fig 2.The gray histogram of CNS lymphoma、Glioblastoma and metastatic tumors. The abscissa represents different gray-scale values in ROI, and the ordinate represents the frequency of occurrence of gray-scale values.
  • Semiautomated quantitative analysis of swallow function using dynamic MRI with image registration and intensity analysis
    Timothy Bray1,2, Ruaridh Gollifer1,3, Simon Morley2, Susan Jawad2, Roganie Govender4, Stuart A Taylor1,2, Nicholas Hamilton4, and David Atkinson1
    1Centre for Medical Imaging, University College London, London, United Kingdom, 2Department of Imaging, University College London Hospital, London, United Kingdom, 3Medical Physics, University College London Hospital, London, United Kingdom, 4Head and Neck Academic Centre, University College London, London, United Kingdom
    We describe and evalute a method for imaging and analysis of pharyngeal and laryngeal motion during the swallow, based on joint image registration and modelling of intensity changes over a dynamic image series acquired at high temporal resolution.
    Figure 2 – Example time series of swallow. Selected images from a healthy volunteer (every fifth slice) are shown from left to right, starting with the top row. In the middle slices, the pharynx constricts and the hyoid and pre-epiglottic fat elevate.
    Figure 3 – Deformation maps and intensity change maps. Deformation magnitude is shown in (a) and is largest in the region of the tongue base and larynx. Intensity changes are shown in (b); in this case there are small intensity changes in the pharynx due to unsaturated tissue being pulled into the imaging slice.
  • Prognostic value of quantitative dynamic contrast-enhanced magnetic resonance imaging and texture analysis for nasopharyngeal carcinoma
    Yuhui Qin1,2, Xiaoping Yu2, Jing Hou2, and Fabao Gao1
    1Department of Radiology, West China Hospital, Chengdu, China, 2Department of Radiology, Affiliated Cancer Hospital of Xiangya School of Medicine, Changsha, China
    1) quantitative DCE-MRI parameters Ktrans, fpv and Ve may help to predict the long-term outcome after treatment for NPC. 2) The texture features of quantitative DCE-MRI parameters before treatment (Kep-perc.10% and Ve-perc.90%) may be predictors of the long-term efficacy of NPC.
    Figure 3. Kaplan-Meier curves of LRRFS (a), LRFS (b), PFS (c) for NPC patients stratified as the Ktrans-low and Ktrans-high groups; and LRRFS (d), LRFS (e) for NPC patients stratified as the fpv-low and fpv-high groups; and DMFS (e) for NPC patients stratified as the ve-low and ve-high groups. Ktrans-low/fpv-low/Ve-low group = patients with a primary lesion pretreatment Ktrans/fpv/Ve value ≤ 0.353/min, 0.034 and 0.289, respectively; Ktrans-high/fpv-high/Ve-high group = patients with a primary lesion pretreatment Ktrans/fpv/Ve value > 0.353/min, 0.034 and 0.289, respectively.
    Figure 4. Kaplan-Meier curves of LRRFS (a), LRFS (b), PFS (c) and DMFS (d) for NPC patients stratified as the ve-perc.90%-low and ve-perc.90%-high groups; and LRRFS (e), LRFS (f) for NPC patients stratified as the Kep-perc.10%-low and Kep-perc.10%-high groups. ve-perc.90%-low/Kep-perc.10%-low group = patients with a primary lesion pretreatment ve-perc.90%/Kep-perc.10% value ≤ 160, 75.5, respectively; ve-perc.90%-high/Kep-perc.10%-high group = patients with a primary lesion pretreatment ve-perc.90%/Kep-perc.10% value > 160, 75.5, respectively.
  • Real-time tyGA Imaging for diagnosis and treatment evaluation of articular disc displacements in the TMJ
    Kilian Stumpf1, Mariam Seyfang2, Bernd Georg Lapatki2, and Volker Rasche1
    1Department of Internal Medicine II, Ulm University Medical Center, Ulm, Germany, 2Department of Orthodontics, Ulm University Medical Center, Ulm, Germany
    A real-time radial tiny golden angle sequence is applied for imaging of the temporomandibular joint. Its use for visualizing anterior disc displacements and assisting in diagnosis and treatment planning and evaluation is demonstrated.
    Figure 2: When starting the movement from a protrusive mandibular position, the sliding window reconstruction with a frame rate of 125 ms allowed the visualization of the repositioning of the condyle (dotted arrow) on the articular disc (solid arrow) (B-E) with subsequent full opening of the mandible (G). During the closing motion the condyle can once again be observed to slip down from the articular disc (J-L).
    Figure 3: Visualization of the jaw motion with an incorporated occlusal splint. Starting in a therapeutic, more anterior and caudal initial position with the condyle (dotted arrow) already positioned on the articular disc (solid arrow), no additional repositioning or disc displacement was observed during the entire motion of the jaw.
  • Diagnostic Consensus in the Interpretation of Ultra-High-Field MRS in Glioma Patients
    Uzay E Emir1,2, Jannie Wijnen3, Olaf E Ansorge4, Evita Wiegers3, Anja van der Kolk5, Alexander Lin6, and Clark Chen7
    1School of Health Sciences, Purdue University, West Lafayette, IN, United States, 2Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, United States, 3Radiology, University Medical Centre Utrecht, Utrecht, Netherlands, 4University of Oxford, Oxford, United Kingdom, 5Antoni van Leeuwenhoek Hospital, Netherlands Cancer Center, Amsterdam, Netherlands, 6Brigham and Women’s Hospital / Dana Farber Cancer Institute, Harvard Medical School, Boston, MA, United States, 7Department of Neurosurgery, University of Minnesota, Minneapolis, MN, United States
    The collection of prospectively acquired UHF MRS spectra from multiple international centres could lead to a widely accepted prognostic precision medicine biomarker detection system for identifying, stratifying, and monitoring IDH1 and IDH2 mutant glioma patients.
    Descriptive measures of the predicted IDH status from the visual inspection
    Information provided to participants at the beginning of the survey.
  • Intra-oral flexible coil for improved visibility of dental root canals in MRI
    Agazi Samuel Tesfai1, Andreas Vollmer2, Ali Caglar Özen1,3, Wiebke Semper-Hogg2, Ute Ludwig1, and Michael Bock1
    1Dept. of Radiology, Medical Physics, Medical Center – University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany, 2Department of Oral and Maxillofacial Surgery, Medical Center – University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany, 3German Consortium for Translational Cancer Research Partner Site Freiburg, German Cancer Research Center (DKFZ), Heidelberg, Germany
    Ex-vivo and in-vivo measurements were performed with a newly developed intra-oral flexible coil for improved SNR and delineation of the dental root canals. 
    Figure 3: Comparison of SNR and root canal visibility between the 32ch head coil (left), LC4 (center) and IFC coupled inductively to LC4 (right).
    Figure 2: Ex-vivo measurements of a phantom show SNR gain of 6 with the inductively-coupled coil (IFC) in comparison to solely using the 4cm loop coil by Siemens (LC4).