Perfusion & Permeability: Applications

Monday 12 May 2014

Sudipto Dolui¹, Raghav Mattay², Ze Wang³, Mack Finkel⁴, Alex Smith², Mark Elliott², Lisa Desiderio², Ben Inglis⁵, Bryon Mueller⁶, Danny J.J. Wang⁷, Lenore J. Launer⁸, Robert Kramer⁸, R. Nick Bryan², and John A. Detre^9
1Department of Neurology, University of Pennsylvania, Philadelphia, Pennsylvania, United States, ²Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, United States, ³Department of Psychiatry, University of Pennsylvania, Philadelphia, Pennsylvania, United States,⁴Germantown Friends School, Philadelphia, Pennsylvania, United States, ⁵Department of Neuroscience, University of California, Berkeley, California, United States, ⁶Department of Psychiatry, University of Minnesota, Minneapolis, Minnesota, United States, ⁷Department of Neurology, University of California, Los Angeles, California, United States, ⁸Laboratory of Epidemiology, Demography, and Biometry, National Institute on Aging, Bethesda, Maryland, United States, ⁹Departments of Neurology and Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, United States

We compared whole brain cerebral blood flow (CBF) measurements obtained using pCASL MRI and phase contrast angiography (PCA) measurements in a large cohort of 544 subjects from the CARDIA study. CBF values showed highly significant correlations throughout the velocity range, providing no suggestion that pCASL labeling efficiency drops at higher mean arterial velocities. There was also considerable individual variability between CBF measured by pCASL versus PCA, suggesting that PCA-based CBF calibration of pCASL labeling efficiency may not be justified at the single subject level.

Eidrees Ghariq¹, Xingxing Zhang¹, Andrew G. Webb¹, Mark A. Van Buchem¹, Albert Dahan², and Matthias J.P. Van Osch^1
1C.J. Gorter Center for High Field MRI, Department of Radiology, Leiden University Medical Center (LUMC), Leiden, Zuid-Holland, Netherlands,²Deparment of Anesthesiology, Leiden University Medical Center (LUMC), Leiden, Zuid-Holland, Netherlands

Regional cerebrovascular reactivity (CVR) to CO2 is increasingly measured with BOLD and ASL MRI. The data processing is based on the assumption of a linear relationship between BOLD/CBF and CO2. However, we show that the BOLD CO2 reactivity curve has a sigmoidal shape, but the CBF-CO2 relationship is linear in the CO2 range of 3 kPa to 8 kPa. These findings underline a cautious approach to interpreting the CO2 CVR data measured with BOLD and support the conclusion that CBF is a more robust tool for CO2 CVR measurements.

Jasper Verbree^1,2, Eidrees Ghariq^1,2, Anne-Sophie Bronzwaer^3,4, Maarten Versluis^1,2, Mat Daemen⁵, Mark van Buchem¹, Albert Dahan⁶, Johannes van Lieshout^3,4, and Matthias van Osch^1,2
1Radiology, Leiden University Medical Center, Leiden, Netherlands, ²C.J. Gorter Center for High-Field MRI, Leiden University Medical Center, Leiden, Netherlands, ³Laboratory for Clinical Cardiovascular Physiology, Academic Medical Center, Amsterdam, Netherlands, ⁴Internal Medicine, Academic Medical Center, Amsterdam, Netherlands, ⁵Pathology, Academic Medical Center, Amsterdam, Netherlands, ⁶Anesthesiology, Leiden University Medical Center, Leiden, Netherlands

Changes in blood flow velocity measured with Transcranial Dopper (TCD) are frequently interpreted as being proportional to cerebral blood flow assuming a constant diameter of the insonated vessel. Reported data on vessel diameter changes under influence of CO2 are inconsistent. High resolution MR imaging was used to measure the diameter of the middle cerebral artery (MCA) in healthy volunteers. Four levels of end-tidal CO2 were administered via a face mask. Results indicate that moderate hypercapnia (+2 kPa above resting concentration) increases MCA diameter 17%. A quadratic model is proposed to correct for diameter changes under different end-tidal CO2 conditions.

Nuno A da Silva¹, Ke Zhang¹, Pavel Chervakov¹, Eleonora Maggioni^1,2, Thomas W Okell³, and N Jon Shah^1,4
1Forschungszentrum Jülich GmbH, Institute of Neuroscience and Medicine - 4, Jülich, Germany, ²Politecnico di Milano, Milano, Italy, ³Centre for Functional Magnetic Resonance Imaging of the Brain, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom,⁴RWTH Aachen, Department of Neurology, Aachen, Germany

In this study we investigate the effect of moderate exercise on brain cerebral blood flow (CBF) using arterial spin labeling (ASL) measurements. A dedicated setup with an ergometer pedal platform in the MR-BrainPET scanner was utilised. We demonstrated that with this setup and by measuring with pseudo-continuous arterial spin labeling (pCASL), the variations of CBF in a healthy brain during exercise and following exercise can be detected and evaluated.

Erin K Englund¹, Michael C Langham², Thomas F Floyd³, Felix W Wehrli², and Emile R Mohler III^4
1Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, United States, ²Department of Radiology, University of Pennsylvania, Philadelphia, PA, United States, ³Department of Anesthesiology, Stony Brook University, Stony Brook, NY, United States, ⁴Department of Medicine, University of Pennsylvania, Philadelphia, PA, United States

A comprehensive investigation of peripheral microvascular function in patients with peripheral artery disease (PAD) is presented. The rate of recovery following induced ischemia is monitored by dynamic acquisition with Perfusion, Intravascular Venous Oxygen saturation, and T2* (PIVOT). Analysis of the association between the ankle-brachial index (ABI), which is the clinical mainstay of PAD detection and diagnosis, and PIVOT-derived time-course metrics found significant correlations between ABI and time to peak perfusion and between ABI and time to peak T₂*.

Mahdi Salmani Rahimi¹, Frank R Korosec^2,3, Kang Wang⁴, James H Holmes⁴, Utaroh Motosugi², Peter Bannas^2,5, and Scott B Reeder^1,2
1Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States, ²Radiology, University of Wisconsin-Madison, Madison, WI, United States, ³Medical Physics, University of Wisconsin-Madison, Madison, WI, United States, ⁴Global MR Applications and Workflow, GE Heatlhcare, Madison, WI, United States, ⁵Radiology, University Hospital Hamburg-Eppendorf, Hamburg, Germany

High spatial and temporal resolution contrast enhanced MRI is the cornerstone of detection and characterization of focal liver lesions. An interleaved variable density undersampling pattern with dual-echo bipolar readouts and data-driven parallel imaging was modified to acquire volumetric images of the liver every four seconds. Parallel imaging calibration lines were only acquired once during the breath-hold. Images acquired in ten patients with focal nodular hyperplasia showed significant improvement in overall quality compared to clinical DCE images. MR angiograms were also obtained from the arterial phase of the time-resolved series, and were found to be comparable to the dedicated conventional MRA.

Vipul R Sheth¹, Qun He¹, Olivier M Girard¹, Robert F Mattrey¹, Graeme M Bydder¹, and Jiang Du^1
1Department of Radiology, University of California San Diego, San Diego, CA, United States

We used an inversion recovery prepared UTE sequence to perform perfusion MRI in cortical bone. This method produced imaging results with fewer artifacts than previous UTE methods. It showed evidence for bi-component behavior (vascular and organic matrix). The method should allow detailed study of cortical bone perfusion.

Ning Lang¹, Min-Ying Lydia Su², Hon J Yu², and Huishu Yuan^1
1Department of Radiology, Peking University Third Hospital, Beijing, China, ²Tu & Yuen Center for Functional Onco-Imaging, Department of Radiological Sciences, University of California, Irvine, CA, United States

DCE-MRI was performed to differentiate 4 spinal lesions (9 myeloma, 22 metastatic cancer, 7 lymphoma, 22 benign tuberculosis). The peak signal enhancement, the steepest wash-in slope and wash-out slope were measured. Two-compartmental pharmacokinetic model was used to obtain Ktrans and kep, by using three different blood curves (fast, medium, and slow). The results showed that kep analyzed by using fast or medium blood curves is the best parameter to differentiate these 4 lesion groups. Ktrans is associated with wash-in slope and kep is associated with wash-out slope. The slow blood curve is not suitable for a short DCE period.

Lucy E Kershaw¹, Jonathan M Bernstein², Stephanie B Withey³, Nicholas J Slevin⁴, Suzanne C Bonington⁵, Bernadette M Carrington⁵, and Catharine M West^2
1Christie Medical Physics and Engineering, The Christie NHS Foundation Trust, Manchester, Gtr Manchester, United Kingdom, ²Translational Radiobiology Group, University of Manchester, Manchester, Gtr Manchester, United Kingdom, ³RRPPS63, University Hospitals Birmingham, Birmingham, United Kingdom, ⁴Clinical Oncology, The Christie NHS Foundation Trust, Manchester, United Kingdom, ⁵Radiology, The Christie NHS Foundation Trust, Manchester, Gtr Manchester, United Kingdom

This study investigated the changes in DCE-MRI parameters due to induction chemotherapy for head and neck squamous cell carcinoma. In RECIST responders, extravascular-extracellular volume was significantly different before and after therapy whereas in non-responders it was not. A third examination at the end of therapy, long-term followup and histological markers of hypoxia might reveal further correlations with early imaging.

Federico D. Pineda¹, Milica Medved¹, Xiaobing Fan¹, Marko Ivancevic², Hiroyuki Abe¹, Akiko Shimauchi¹, Charlene Sennet¹, Gillian Newstead¹, and Gregory S. Karczmar^1
1Radiology, The University of Chicago, Chicago, IL, United States, ²Philips Healthcare, Netherlands

DCEMRI of the breast is a valuable tool in the detection and staging of breast cancer. Radiologists rely on measures of uptake and washout of contrast media by analyzing the signal enhancement of suspicious lesions. Signal enhancement can vary due to scanner and acquisition parameters. Eleven volunteers were scanned at both 1.5T and 3T to quantify the variability in signal enhancement measures. We found that SER and time to peak enhancement had the lowest variability. Conversion from signal enhancement to concentration of contrast media did not significantly reduce variability, likely due to B1 inhomogeneity and uncertainty in native T1 estimation.