Gabriel Hoffmann^1,2, Miriam Reichert¹, Jens Göttler¹, Michael Helle³, Kim van de Ven⁴, Claus Zimmer^1,2, Moritz Hernandez Petzsche^1,2, Hans Liebl^1,5, Nico Sollmann^1,6, Christine Preibisch^1,2, and Stephan Kaczmarz^1,2,7
1Department of Diagnostic and Interventional Neuroradiology, School of Medicine, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany, ²TUM-Neuroimaging Center, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany, ³Philips Research, Hamburg, Germany, ⁴Philips Healthcare, Best, Netherlands, ⁵Department of Radiology, Neuroradiology and Minimal-Invasive Therapy, Klinikum Bogenhausen, Munich, Germany, ⁶Department of Diagnostic and Interventional Radiology, University Hospital Ulm, Ulm, Germany, ⁷Philips Healthcare, Hamburg, Germany

Vessel-selective imaging is promising to examine collateral blood supply in asymptomatic internal carotid artery stenosis (ICAS). Established modalities like digital subtraction angiography are invasive, not quantitative and associated with potential complication risks. A viable non-invasive alternative is super-selective arterial spin labelling, providing perfusion territories of individual arteries. We present data from seven asymptomatic ICAS patients and four age-matched healthy controls. We compared individual perfusion territory maps to an atlas of vascular territories and evaluated intra-hemispheric differences, allowing for quantitative assessment of stenotic mal-perfusion as well as compensatory collateral blood supply from the contralateral ICA.

Hyun-Seo Ahn¹ and Sung-Hong Park^1
1Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology, Daejeon, Korea, Republic of

Imaging methods for the non-invasive measurement of renal function, such as glomerular filtration rate (GFR), are promising. In this study, we propose a renal perfusion kinetic model to estimate the blood transfer rate constant ($$$k_G$$$) in glomerulus with the multi-slice multi-delay diffusion-weighted arterial spin labeling sequence. Mean cortical $$$k_G$$$ values with a caffeine challenge were higher than those with no caffeine challenge, consistent with previous studies with GFR. The current study is promising in that it shows a potential availability of $$$k_G$$$ as a non-invasive quantitative measure of renal function.

Jörn Huber¹, Daniel Hoinkiss¹, Meghashree Channaveerappa¹, and Matthias Günther^1,2
1Fraunhofer MEVIS, Bremen, Germany, ²Faculty 1 (Physics/Electrical Engineering), University of Bremen, Bremen, Germany

Assessment of liver perfusion can yield valuable information about diseases like carcinoma and cirrhosis. Arterial spin labeling enables contrast-free measurements of liver perfusion with the drawback of increased motion sensitivity. Since timed breathing protocols prolong scan times, a novel prospective motion correction technique is presented, adjusting the initial saturation and image readout to the current position of the liver during the breathing cycle. The presented technique is compatible with highly suppressed signals, typically encountered in modern ASL imaging and achieved a significant decrease of cranial-caudal liver translation in acquired 3D GRASE volumes. 

Sergio M. Solis-Barquero^1,2, Verónica Aramendia-Vidaurreta^1,2, Marta Vidorreta³, Rebeca Echeverria-Chasco^1,2, Leyre García-Ruiz^1,2, Ana Ezponda^1,2, Gorka Bastarrika^1,2, and María A. Fernández-Seara^1,2
1Departament of Radiology, Clínica Universidad de Navarra, Pamplona, Navarra, Spain, ²IdiSNA, Instituto de Investigación Sanitaria de Navarra, Navarra, Spain, ³Siemens Healthineers, Madrid, Spain

The spleen plays an important role in diseases related to portal circulation. Pseudo-continuous arterial spin labeling (PCASL) was used to assess the Splenic Blood Flow (SBF) using six different post labeling delays in five different healthy volunteers. SBF and ATT maps were generated by fitting the one compartment Buxton kinetic model. This study shows the feasibility of using single and multi-delay PCASL to measure blood flow in the spleen. Obtained SBF values are in agreement with previous studies. PCASL enables a reliable measure of splenic blood flow in healthy volunteers.

David A Reiter¹, Jingting Yao², Scott Edwards¹, Marcos Coutinho Schechter¹, Maya Fayfman¹, Gabriel Santamarina¹, Paula Nesbeth¹, Vincent Giacalone¹, Gerardo Blanco¹, Thorsten Feiweier³, Rabindra Tirouvanziam¹, Jessica Alvarez¹, Benjamine Risk¹, and Ravi Rajani^1
1Emory University, Atlanta, GA, United States, ²Massachusetts General Hospital, Boston, MA, United States, ³Siemens Healthcare GmbH, Erlangen, Germany

Here we apply intravoxel incoherent motion (IVIM) and fractional Fickian diffusion (FFD) models to multi-b-value diffusion-weighted-MRI to study tissue cellular and resting microvascular properties of the foot of patients with diabetic foot ulcer. We report preliminary results from an ongoing study comparing patients with type 2 diabetes and persistent plantar foot ulcers with healthy age- and BMI-matched individuals. Pseudo-diffusion and mean diffusion coefficients and microvascular volume fraction were elevated in patients, showing large effect sizes in subregions. This approach may prove useful for evaluating patients with ulcers to prognosticate tissue at risk of poor wound healing.

Sebastian Lambrecht^1,2, Dapeng Liu^1,3, Omar Dzaye⁴, Matthias Holdhoff⁴, Peter van Zijl^1,3, Qin Qin^1,3, and Doris Lin^1,3
1Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, United States, ²Institute of Neuroradiology, University Hospital LMU Munich, Munich, Germany, ³F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States, ⁴Department of Oncology, The Johns Hopkins University School of Medicine, Baltimore, MD, United States

Perfusion measures were compared between VSASL and DSC methods at 1.5T in 28 patients with treated high-grade glioma assigned into 2 groups: “tumor” (with detectable enhancing tumor, n=9) and “non-tumor” (without detectable tumor, n=19).  All measures (rCBF and tSNR from VSASL, rCBV and rCBF from DSC) showed significant difference between “tumor” and “non-tumor” groups allowing reliable discrimination. In general, there was moderate to excellent agreement and correlation between these measures derived from VSASL vs. DSC. Hence, VSASL has potential to serve as a viable non-invasive alternative to DSC perfusion in the clinical disease surveillance without the need for exogenous contrast.

Helen Sporkin¹, Toral Patel², Yaqub Betz³, Christopher Kramer^2,3, and Craig Meyer^1,4
1Biomedical Engineering, University of Virginia, Charlottesville, VA, United States, ²Cardiac Imaging, University of Virginia, Charlottesville, VA, United States, ³Cardiology, University of Virginia, Charlottesville, VA, United States, ⁴Radiology and Medical Imaging, University of Virginia, Charlottesville, VA, United States

Peripheral arterial disease is a prevalent atherosclerotic disease characterized by atherosclerotic lesions in the limbs. Patients with PAD have been shown to have a delayed phosphocreatine recovery due to chronic ischemia. Patients with PAD may be candidates for revascularization, but outcomes are variable.  CrCEST allows for creatine concentrations to be monitored at high spatial resolution, while ASL quantifies perfusion into tissue. We use this combination to revascularization in patients undergoing both endovascular and surgical procedures. Preliminary results link improvement in CrCEST decay curves and improved functional walk scores, while increased perfusion seen on ASL does not necessarily correlate with improvement.

Beatriz E. Padrela¹, Luigi Lorenzini¹, Lyduine E. Collij¹, Mara ten Kate¹, Anouk den Braber^2,3, Jori Tomassen², Bart N.M. van Beckel¹, Pieter Jelle Visser², Frederik Barkhof^1,4, Jan Petr⁵, and Henk J.M.M. Mutsaerts^1
1Department of Radiology and Nuclear Medicine, Amsterdam Neuroscience, Amsterdam University Medical Center, Location VUmc, Amsterdam, Netherlands, ²Department of Neurology, Alzheimer Center, Neuroscience Campus Amsterdam, VU University Medical Center, Amsterdam, the Netherlands, Amsterdam, Netherlands, ³Department of Biological Psychology, Vrije Universiteit Amsterdam, Amsterdam, Netherlands, ⁴Queen Square Institute of Neurology and Centre for Medical Image Computing (CMIC), University College London, London, United Kingdom, ⁵Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Dresden, Germany

Studying the association between cerebral blood flow (CBF), amyloid burden, and vascular risk factors in a cognitively unimpaired elderly population could clarify the role of CBF as a biomarker of cognitive decline. In 196 cognitively unimpaired participants, regional CBF was associated with regional amyloid-PET Centiloid. Vascular risk scores as measured by the Framingham risk score combined with amyloid Centiloid values were associated with increased CBF in vascular territories. Longitudinally, global CBF changes were associated with baseline precuneus amyloid burden.