Stanley D.T. Pham¹, Rick J. van Tuijl¹, Jonas W. Bartstra¹, Tim C. van den Beukel¹, Geert Jan Biessels², Pim A. de Jong¹, Wilko Spiering³, Birgitta K. Velthuis¹, and Jaco J.M. Zwanenburg^1
1Radiology, UMC Utrecht, Utrecht, Netherlands, ²Neurology and Neurosurgery, UMC Utrecht, Utrecht, Netherlands, ³Vascular Medicine, UMC Utrecht, Utrecht, Netherlands

This feasibility study aimed to detect drug effects on perforating artery velocity as measured with two-dimensional phase-contrast (2D-PC) velocity measurements at 3T-MRI. Seventeen patients with pseudoxanthoma elasticum were included into a treatment group who received etidronate (n=9) and into a placebo group (n=8). No significant differences were found between both groups at baseline and one-year follow-up. In the etidronate group, mean velocity (V_mean) was significantly higher at follow-up (5.61 [4.77–6.45] cm/s) compared to baseline (4.80 [4.05–5.54] cm/s). In the placebo group, V_mean did not increase significantly. Measuring drug effects was feasible using 2D-PC measurements at 3T-MRI.

Slim Fellah¹, Chunwei Ying¹, Kristin Guilliams¹, Melanie Fields¹, Yasheng Chen¹, Joben Lewis¹, Amy Mirro¹, Rachel Cohen¹, Nkemdilim Igwe¹, Cihat Eldeniz¹, Dengrong Jiang², Hanzhang Lu², Jin-Moo Lee¹, Andria Ford¹, and Hongyu An^1
1Washington University School of Medicine, Saint Louis, MO, United States, ²Johns Hopkins University School of Medicine, Baltimore, MD, United States

We evaluated cerebral oxygen extraction fraction (OEF) in patients with sickle cell disease (SCD) and controls using two MR techniques:  asymmetric spin echo (ASE) and T2-relaxation-under-spin-tagging (TRUST). We hypothesized that both methods would yield similar OEF and that TRUST-derived OEF would be elevated in patients with SCD vs. controls as previously found using ASE-derived OEF.  ASE-derived and TRUST-derived OEF using the Lu 2012 calibration model showed a positive correlation (rho=0.823, p<0.001). Conversely, ASE-derived vs. TRUST-derived OEF using the Bush 2021 model showed a negative association (rho=-0.569, p<0.001). The directionality of these associations was heavily dependent on the calibration model used.

Yi-Fen Yen¹, Joseph B Mandeville¹, Yin-Ching Chan¹, Suk-Tak Chan¹, Erin E Hardy¹, Jay Janz², Steven Arkin², Denis Rybin², Kelly Knee², Debra D Pittman², and James A Goodman^2
1Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Chalrestown, MA, United States, ²Pfizer, Inc, Cambridge, MA, United States

We have assessed cerebral blood flow (CBF), venous T2, and hematocrit (Hct) in mice to characterize the performance of MR markers of cerebral physiology in wildtype (WT) mice and the Townes transgenic mouse model of Sickle Cell Disease (SCD). SCD mice exhibited increased CBF, decreased venous T2, and decreased Hct compared to matched WT mice. Combining MR measures of CBF and venous T2 with Hct measurement improved the disease-specific differentiation. Test-retest variability was approximately 20% for CBF and venous T2 and 10% for Hct. Methods employed in this study are fully translational to the clinic.

Laurel Dieckhaus¹, Ali Kamali¹, Emily C Peters², Collin A Preszler¹, Christa M Sonderer¹, Paulo Pires², Kaveh Laksari¹, and Elizabeth B Hutchinson^1
1Biomedical Engineering, University of Arizona, Tucson, AZ, United States, ²Physiology, University of Arizona, Tucson, AZ, United States

To examine the first hours after brain injury, we utilized photoacoustic imaging (PAI), ultrasound (US), and color doppler (CD) alongside MRI metrics. We wanted to investigate the early pathomechanisms that involve hemodynamic response such as blood flow, oxygenation, and edema. 

Dominick Jon Romano¹, Qihao Zhang¹, Ilhami Kovanlikaya², Gloria Chia-Yi Chiang², Pascal Spincemaille², and Yi Wang^3
1Biomedical Engineering, Cornell University, New York, NY, United States, ²Radiology, Weill Cornell Medical College, New York, NY, United States, ³Radiology, Cornell University, New York, NY, United States

A recently proposed perfusion analysis method, Quantitative Transport Mapping (QTM), was applied in malignant Glioma (grade III and IV) to obtain the flow speed map. Pathological lesions were separated into DCE-Enhancing, Darkening, and total affected ROIs. The average speed scalar for each ROI suggests that DCE-Enhancing tumor presents with significantly increased speed while non-enhancing tumor does not experience a speed change.

Katharina Witzmann^1,2, Felix Raschke^1,2, Tim Wesemann³, Steffen Appold^2,4, Mechthild Krause^1,2,4,5,6, Jennifer Linn³, and Esther G.C. Troost^1,2,4,5,6
1Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiooncology – OncoRay, Dresden, Germany, ²OncoRay - National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany, ³Institute of Neuroradiology, University Hospital Carl Gustav Carus and Medical Faculty of Technische Universität, Dresden, Germany, ⁴Department of Radiotherapy and Radiation Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany, ⁵German Cancer Consortium (DKTK), Partner Site Dresden, and German Cancer Research Center (DKFZ), Heidelberg, Germany, ⁶National Center for Tumor Diseases (NCT), Partner Site Dresden, Germany: German Cancer Research Center (DKFZ), Heidelberg, Germany; Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany, and; Helmholtz Association / Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Dresden, Germany

Imaging biomarkers capable of distinguishing between tumor recurrence and treatment effect are of high relevance for radiation therapy. In 14 glioma patients, we analyzed changes in relative cerebral blood volume (rCBV) in areas of hyperintensities on T2-weighted magnetic resonance imaging (MRI) appearing after irradiation with protons. rCBV values were evaluated comparing the baseline and the latest follow-up measurement both visually and based on histograms. A significant rCBV perfusion decrease was observed in those hyperintensities, which may be interpreted as treatment effect. Further work is needed correlating the rCBV changes with histology and patient outcome.

Markus Fahlström¹, Anders Lewén², Per Enblad², and Johan Wikström^1
1Surgical Sciences, Uppsala University, Uppsala, Sweden, ²Neuroscience, Uppsala University, Uppsala, Sweden

Moyamoya disease is a cerebrovascular disease where changes to oxygen extraction fraction (OEF) and cerebral metabolic rate of oxygen (CMRO₂) are important parameters to assess the risk of future ischemic stroke. By applying a microvasculature model to dynamic susceptibility contrast (DSC) perfusion data parametric maps of both OEF and CMRO₂ can be generated. For both OEF and CMRO₂ significant differences between affected and unaffected vascular territorial regions were found. OEF and CMRO₂ derived from DSC perfusion shows promise in detecting cerebral hemodynamic impairment in patients with moyamoya disease. However, further investigations are needed to clarify the clinical potential.

Pieter T Deckers¹, Jeroen CW Siero^2,3, Annick Kronenburg¹, Kees PJ Braun⁴, Bart van der Zwan¹, and Alex A Bhogal^2
1Neurosurgery, UMC Utrecht, Utrecht, Netherlands, ²Imaging, UMC Utrecht, Utrecht, Netherlands, ³Spinoza Centre for Neuroimaging, Amsterdam, Netherlands, ⁴Pediatric Neurology, UMC Utrecht, Utrecht, Netherlands

Measuring cerebrovascular reactivity (CVR) under narcosis is underreported, while narcosis is often necessary for pediatric or cognitively impaired patients. When acetazolamide is used in awake patients, maximum CBF increase reaches a plateau after ~12min. Using ASL- and BOLD-MRI with acetazolamide we showed that for pediatric moyamoya patients the response is different. Patients under narcosis show lower CVR and reach peak CBF earlier (after around six minutes), after which CBF decreases again without the plateau-phase. This shows the response to acetazolamide is distinctively different between awake and narcosis patients and caution is warranted during interpretation of narcosis CVR images.