Yoshiharu Ohno^1,2, Masao Yui³, Kota Aoyagi³, Yoshimori Kassai³, Daisuke Takenaka⁴, Kazuhiro Murayama¹, and Takeshi Yoshikawa^2
1Radiology, Fujita Health University School of Medicine, Toyoake, Japan, ²Radiology, Kobe University Graduate School of Medicine, Kobe, Japan, ³Canon Medical Systems Corporation, Otawara, Japan, ⁴Diagnostic Radiology, Hyogo Cancer Center, Akashi, Japan

    Direct comparison of non-small cell lung cancer (NSCLC) recurrence evaluation among these four methods in large prospective cohort more than 400 patients had not been reported.  We hypothesize that whole-body MRI as well as PET/MRI had better potential for postoperative NSCLC recurrence than PET/CT and standard radiological examination in large prospective cohort.  The purpose of this study was thus to compare the diagnostic performance of whole-body MRI, PET/MRI, PET/CT and standard radiological examination for postoperative NSCLC recurrence assessment in large prospective cohort more than 400 patients.

Patrick Metze¹, Tobias Speidel², Fabian Straubmüller¹, and Volker Rasche^1,2
1Department of Internal Medicine II, University Ulm Medical Center, Ulm, Germany, ²Core Facility Small Animal Imaging (CF-SANI), Ulm University, Ulm, Germany

Most self-gating methods rely on information that is extracted either from k-space itself or from high temporal resolution sliding-window images. The obtained one-dimensional gating signal is analysed with respect to a dominant and characteristic frequency. These approaches are prone to fail in case of highly non-uniform motion.

The presented application of nonuniform Self-Gating based on a two-dimensional correlation matrix is capable of achieving high resolution proton fraction maps in human subjects with non-regular respiratory motion without the need of time consuming respiratory gating during acquisition.

Vicki Huang¹, Steven Guan¹, Nick Tustison¹, Kun Qing¹, Yun Shim², John Mugler¹, Talissa Altes³, Dana Albon², Deborah Froh², Borna Mehrad⁴, James Patrie⁵, Allan Ropp¹, Lucy Gettle², Mu He¹, and Jaime Mata^1
1Radiology & Medical Imaging, University of Virginia, Charlottesville, VA, United States, ²Medicine, University of Virginia, Charlottesville, VA, United States, ³Radiology, University of Missouri, Columbia, MO, United States, ⁴University of Florida, Gainesville, FL, United States, ⁵Public Health, University of Virginia, Charlottesville, VA, United States

The results of this study indicated that hyperpolarized Xe-129 MR 3D-SBCSI is sensitive to physiology of lung diseases and can therefore be used to differentiate lung disease and monitor disease progression on regional level and characterizing disease phenotypes and co-morbidities in the future.

Mary Neal^1,2, Benjamin Pippard^1,2, Adam Maunder³, Rod Lawson⁴, Holly F. Fisher⁵, John N. S. Matthews⁵, Kieren Hollingsworth^1,2, A. John Simpson², Jim M. Wild³, and Pete Thelwall^1,2
1Newcastle Magnetic Resonance Centre, Newcastle University, Newcastle upon Tyne, United Kingdom, ²Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, United Kingdom, ³POLARIS, Academic Radiology, University of Sheffield, Sheffield, United Kingdom, ⁴Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield, United Kingdom, ⁵Institute of Health and Society, Newcastle University, Newcastle upon Tyne, United Kingdom

¹⁹F-MRI of inhaled perfluoropropane can be used to assess regional pulmonary ventilation. We conducted a prospective multi-centre reproducibility study in 40 healthy volunteers. Same-day static breath-hold ¹⁹F-MR images with 1 cm isotropic resolution were acquired on four occasions for each volunteer following inhalation of a perfluoropropane/oxygen gas mixture. Percentage ventilated lung volume (%VV) was calculated for all volunteers, reflecting the inhalation protocol, imaging protocol, and image registration and segmentation process applied. Volunteer %VV was determined to within ±1.7% (95% CI). Gas inhalations were well tolerated by all volunteers with no adverse events.

Rachel L Eddy^1,2, Christopher Licskai³, David G McCormack³, and Grace Parraga^1,2,3
1Robarts Research Institute, London, ON, Canada, ²Department of Medical Biophysics, Western University, London, ON, Canada, ³Division of Respirology, Department of Medicine, Western University, London, ON, Canada

Pulmonary functional MRI measurements have never been evaluated for the generation of imaging-based asthma patient clusters, although computed tomography (CT)-based clusters have been determined. Here we investigated hyperpolarized inhaled gas MRI ventilation in combination with CT airway measurements in 60 patients with asthma and identified 6 pulmonary structure-function imaging-based clusters using MRI ventilation defect percent (VDP) and CT airway measurements. These clusters reflect proximal and distal airway abnormalities in asthma and may be used to stratify patients for treatment decisions.

Guilhem Jean Collier¹, Alberto Biancardi¹, Paul J Hughes¹, Laurie Smith¹, Grace T Mussel¹, Helen Marshall¹, Ho F Chan¹, Graham Norquay¹, and Jim M Wild^1
1Department of Infection, Immunity & Cardiovascular Disease, University of Sheffield, Sheffield, United Kingdom

This work applies a clustering method developed for image analysis of hyperpolarised gas lung ventilation MRI to a cohort of patients referred from a severe asthma clinic for investigation of breathlessness. Patients underwent spirometry tests and imaging at baseline and after inhalation of Salbutamol to assess reversibility. In a subset of patients, images pre and post bronchodilator were registered and a novel treatment response mapping method was applied. Results show significant correlations at baseline between imaging markers and FEV1% and between their percentage changes and the reversibility testing. The treatment response mapping method offers additional robust additional insights.

Ziyi Wang¹, Leith Rankine¹, Aparna Swaminathan¹, Elianna A Bier¹, Matthew P Thorpe², Robert Tighe¹, Yuh Chin Huang¹, Sudarshan Rajagopal¹, and Bastiaan Driehuys^1
1Duke University, Durham, NC, United States, ²Mayo Clinic, Rochester, MN, United States

Hyperpolarized ¹²⁹Xe gas exchange (GX) MR imaging of pulmonary ventilation, barrier uptake and red blood cell (RBC) transfer has shown sensitivity to a wide range of pathology. However, the physiological interpretation of regional RBC transfer defects is not yet fully established and its connection to conventional measures has yet to be studied in a broad range of pathology. Here we evaluate the extent to which ¹²⁹Xe RBC transfer reflects local perfusion, by testing its spatial correlation to ^99mTc scintigraphy and propose a generalized model connecting ¹²⁹Xe gas exchange metrics to the membrane and capillary blood volume components of DL_CO.

Mu He¹, Lindsay A. L. Somerville¹, Nicolas J. Tustison², Jaime F. Mata², Joanne M. Cassani³, Roselove Nunoo-Asare², Alan M. Ropp², Wilson G. Miller², Yun M. Shim¹, Talissa A. Altes³, John P. Mugler², and Eduard E. de Lange^2
1Department of Pulmonary and Critical Care, University of Virginia, Charlottesville, VA, United States, ²Department of Radiology and Medical Imaging, University of Virginia, Charlottesville, VA, United States, ³Department of Radiology, University of Missouri, Columbia, MO, United States

With hyperpolarized ³He MRI regional differences in airflow can be assessed. We sought to evaluate the changes in regional ventilation following bronchodilator therapy in patients with asthma. Baseline and post-treatment ³He/¹H scans were co-registered, and normalized to enable serial comparison. Linear binning quantification was applied to the ventilation scan data to obtain quantitative metrics. Baseline and post-treatment scans were compared for regions of ventilation improvement or worsening. Lobar analysis was performed to identify ventilation abnormalities in each lobe. It was found that in asthmatics with bronchodilator response, ventilation improved globally, with most significant improvement in the upper and middle lobes.

Marrissa McIntosh¹, Rachel Eddy¹, Danielle Knipping², Tamas Lindenmaier², David McCormack³, Christopher Licskai³, Cory Yamashita³, and Grace Parraga^4
1Department of Medical Biophysics, Robarts Research Institute, Western University, London, ON, Canada, ²Robarts Research Institute, Western University, London, ON, Canada, ³Division of Respirology, Department of Medicine, Western University, London, ON, Canada, ⁴Department of Medical Biophysics, Division of Respirology, Department of Medicine, Robarts Research Institute, Western University, London, ON, Canada

¹²⁹Xe MRI ventilation images consist of embedded texture features that help explain abnormal ventilation heterogeneity. We postulated that such texture features may help predict severe asthma patient response to anti-IL-5 therapies. Therefore, we employed supervised shallow learning techniques to identify specific ¹²⁹Xe MRI features that help predict anti-IL-5 responders. Texture analysis yielded features that were superior to clinical measurements in identifying severe asthma patients that responded to anti-IL-5 therapy after 28 days. These promising results suggest that texture analysis may help predict asthmatics more likely to respond, before treatment is initiated.

Ho-Fung Chan¹, Alberto Biancardi¹, Bilal A Tahir¹, Nicholas D Weatherley¹, Ronald A Karwoski², Brian J Bartholmai², Stephen M Bianchi³, and Jim M Wild^1
1Academic Radiology, University of Sheffield, Sheffield, United Kingdom, ²Biomedical Imaging Resource, Mayo Clinic, Rochester, MN, United States, ³Academic Directorate of Respiratory Medicine, Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield, United Kingdom

A framework for spatial co-registration of ³He diffusion-weighted (DW)-MRI and high resolution CT (HRCT) images was developed and implemented in a cohort of fifteen idiopathic pulmonary fibrosis participants. Voxel-wise comparison of ³He DW-MRI derived apparent diffusion coefficient (ADC) and mean alveolar dimension (Lm_D­)  with CALIPER image analysis software classifications revealed that the largest DW-MRI metrics are in voxels classified as honeycombing. Furthermore, Lm_D values in voxels classified as normal by CALIPER were larger than those from age-matched healthy volunteers, suggesting DW-MRI may detect microstructural changes even in areas of the lung determined as macroscopically normal by HRCT.

Luis A Loza¹, Stephen J Kadlecek¹, Mehrdad Pourfathi¹, Kai Ruppert¹, Tahmina S Achekzai¹, Ian F Duncan¹, and Rahim R Rizi^1
1Radiology, University of Pennsylvania, Philadelphia, PA, United States

129Xe’s high solubility in tissue and blood, coupled with its dramatic change in chemical shift based on local chemical environment, enables quantitative measurements of blood oxygenation. In this work, we demonstrate a technique for distinguishing oxygenated vs. deoxygenated blood in the mouse circulatory system in vivo. Time-resolved dissolved-phase images and spectra were used to identify spectral signatures for 129Xe dissolved in oxygenated and deoxygenated blood, which were then applied to a mouse model of lung cancer to temporally assess regional changes in pulmonary blood oxygenation. The results presented here demonstrate

Lea Behrendt^1,2, Andreas Voskrebenzev^1,2, Cristian Crisosto Gonzalez^1,2, Marcel Gutberlet^1,2, Helen Marshall³, Anna-Maria Dittrich⁴, Laurie Smith³, Paul Hughes³, Jim Wild³, and Jens Vogel-Claussen^1,2
1Institute of Diagnostic and Interventional Radiology, Hannover Medical School, Hannover, Germany, ²Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), German Center for Lung Research (DZL), Hannover, Germany, ³University of Sheffield, Sheffield, United Kingdom, ⁴Paediatric Pneumology and Neonatology, Hannover Medical School, Hannover, Germany

Dynamic contrast enhanced (DCE) MRI is an established technique for measurement of lung perfusion, but requires the administration of contrast agents and a breath hold. Thus, methods for contrast agent free assessment of lung perfusion in free breathing, like phase resolved functional lung (PREFUL) MRI, are desirable. Therefore, in this dual center and dual vendor feasibility study, we validated PREFUL MRI against DCE MRI in patients with CF. Perfusion defect percentage (QDP) maps of both methods were calculated, showing an overlap of 61% for the whole lung. Further, a strong correlation between QDP_PREFUL and QDP_DCE was found (r=0.70, p=0.005).

Brandon Zanette¹, Yonni Friedlander^1,2, Samal Munidasa^1,2, and Giles Santyr^1,2
1Translational Medicine, The Hospital for Sick Children, Toronto, ON, Canada, ²Medical Biophysics, University of Toronto, Toronto, ON, Canada

Hyperpolarized 129Xe MRI is an emergent tool for the quantification of ventilation defects in the lungs. 129Xe is typically imaged with 2D gradient recalled echo (2D-GRE) which may require lengthy breath-holds (up to 16s) to image the lung. This may be problematic in subjects who are not able to comply with these breath-hold constraints. Non-Cartesian spiral imaging samples k-space more efficiently, reducing the acquisition duration. In this work a 3D stack-of-spirals (3D-SoS) imaging sequence was developed and tested in healthy adults alongside conventional 2D-GRE for hyperpolarized 129Xe ventilation mapping, showing equivalent ventilation defect percent quantification in a ~2 s scan.

Alexander M Matheson¹, Rachel L Eddy¹, Jonathan L MacNeil², Marrissa L McIntosh¹, and Grace Parraga^1,2
1Medical Biophysics, Robarts Research Institute, Western University, London, ON, Canada, ²School of Biomedical Engineering, Robarts Research Institute, Western University, London, ON, Canada

Thoracic segmentations are crucial for accurate measurements of normalized lung ventilation, perfusion and gas exchange. Current semi-automated methods are time consuming, require experienced readers, and lack the standardization of fully-automated methods, such as convolutional neural networks. We retrospectively pooled data from 449 healthy and respiratory disease participants, resulting in a 55,000 slice augmented data set to train a dense v-net neural network. The network produced segmentations qualitatively matching semi-automated methods, with high Dice scores and an area under the receiver operating characteristic curve of 0.997. Implementation on the NiftyNet platform permits quick model dissemination for multi-site validation. 

Junlan Lu¹, Ziyi Wang², John C. Nouls³, Kush Gulati², Elianna Bier², David Mummy³, and Bastiaan Driehuys^3
1Medical Physics Graduate Program, Duke University, Durham, NC, United States, ²Biomedical Engineering, Duke University, Durham, NC, United States, ³Radiology, Duke University, Durham, NC, United States

The presence of RF inhomogeneity in hyperpolarized 129Xe ventilation MRI affects quantitative analysis and interpretation. These inhomogeneities are commonly corrected using the N4ITK algorithm, which retrospectively calculates a smoothly varying bias field with non-uniform intensity normalization. However, this algorithm has not been rigorously validated for functional imaging. Here we show, using flip angle maps derived directly from 3D-radial acquisitions of ventilation, that N4ITK may over-correct bias field and remove inherent physiological gradients. We illustrate this comparison by a combination of simulation, phantom, and in vivo ventilation imaging.