Room 355 EF

13:30 - 15:30

Moderators:

David J. Collins, Matthias J. P. van Osch

Henri J.M.M. Mutsaerts¹, Edo Richard², Dennis F.R. Heijtel¹, Charles B.L.M. Majoie¹, and Aart J. Nederveen^1
1Radiology, Academic Medical Center, Amsterdam, Netherlands, ²Neurology, Academic Medical Center, Amsterdam, Netherlands

Transit time measurements may not only improve the quantification of arterial spin labeling but also provide valuable diagnostic information that is unavailable with cerebral blood flow measurements alone. This study estimates micro-vascular arterial transit time by Flow-Encoding Arterial Spin Tagging (FEAST) in a large sample of community-dwelling elderly. The measured transit times show a consistent spatial pattern and depend on age and gender. If no transit time maps are available, our linear regression parameters provide an alternative to a fixed transit time.

Marjorie Villien¹, Pierre Bouzat¹, Thomas Rupp², Paul Robach³, Laurent Lamalle⁴, Irène Troprès⁴, François Estève⁵, Alexandre Krainik⁶, Patrick Levy², Jan M. Warnking¹, and Samuel Verges^2
1Grenoble Institut of Neurosciences, INSERM, Grenoble, France, ²Laboratoire HP2, INSERM, Echirolles, France, ³Ecole Nationale de Ski et d’Alpinisme, Chamonix, France, ⁴SFR1, Université Joseph Fourier, Grenoble, France, ⁵ESRF, Grenoble, France, ⁶Clinique universitaire de neuroradiologie et d'IRM, CHU Grenoble, Grenoble, France

We assess the effects of a sojourn of 6 days at 4,350m on cerebral perfusion and on cerebrovascular reactivity to CO2 using ASL at sea level and transcranial Doppler ultrasound at altitude. We demonstrate that high altitude exposure significantly decreases vasoreactivity to CO2. The increase in CBF observed after several days at high altitude is not only the consequence of the vasodilating effect of hypoxia but probably involves other mechanisms such as changes in cerebral autoregulation and angiogenesis. This study is the first to measure cerebral perfusion and vasoreactivity with ASL after a prolonged stay at high altitude.

Yi Zhang¹, Joseph Harrison², Oscar San Emeterio Nateras¹, Steven Chalfin², and Timothy O. Duong^1,2
1Radiology, University of Texas Health Science Center at San Antonio, San Antonio, TX, United States, ²Ophthalmology, University of Texas Health Science Center at San Antonio, San Antonio, TX, United States

Retinitis pigmentosa (RP) is a heterogeneous hereditary disease characterized by photoreceptor degeneration and retinal pigment deposits. Altered ocular blood circulation has been implicated in the degenerative process and/or the pathogenesis of RP. This study demonstrates a novel MRI approach to study the circulatory changes associated with RP in unanesthetized humans. MRI indicates significantly reduced blood flow (BF) in RP retina with a strong link to its suppressed electroretinogram responses.

Peiying Liu¹, Ivan E. Dimitrov^1,2, Trevor Andrews^2,3, David E. Crane⁴, Jacinda K. Dariotis⁵, John Desmond⁶, Julie Dumas³, Guillaume Gilbert², Anand Kumar⁷, Jean-Maxime Leroux⁸, Bradley MacIntosh^4,9, Shaolin Yang⁷, Guanghua Xiao¹⁰, and Hanzhang Lu^1
1Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas, United States, ²Philips Medical Systems, Cleveland, Ohio, United States, ³University of Vermont College of Medicine, Burlington, Vermont, United States, ⁴Heart and Stroke Foundation Centre for Stroke Recovery, Sunnybrook Research Institute, Toronto, Ontario, Canada,⁵Department of Population, Family, and Reproductive Health, Johns Hopkins University, Baltimore, Maryland, United States, ⁶Department of Neurology, Johns Hopkins University, Baltimore, Maryland, United States, ⁷Department of Psychiatry, University of Illinois at Chicago, Chicago, Illinois, United States, ⁸Department of Radiology, Hospital of the University of Montreal, Montreal, Quebec, Canada, ⁹Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada, ¹⁰Department of Clinical Sciences, University of Texas Southwestern Medical Center, Dallas, Texas, United States

Venous blood oxygenation (Yv) is critical for the quantification of CMRO2, a key biomarker for brain tissue viability and functionality. However, non-invasive quantification of Yv has proved to be challenging. Recently, a T2-Relaxation-Under-Spin-Tagging (TRUST) MRI technique was developed to measure global Yv in the superior sagittal sinus. In this work, we evaluated the applicability and reliability of TRUST in a multi-site setting. We compared Yv values (i.e. accuracy) and standard errors of Yv estimation (i.e. precision) across six imaging centers, and showed that the TRUST sequence can be effectively transferred and performed on a standard 3T scanner at remote sites.

Xin Li¹, Jeffrey M. Njus¹, Seymur Gahramanov², Csanad G. Várallyay², John W. Grinstead³, Charles S. Springer, Jr.¹, Edward A. Neuwelt², and William D. Rooney^1
1Advanced Imaging Research Center, Oregon Health & Science University, Portland, Oregon, United States, ²Department of Neurology, Oregon Health & Science University, Portland, Oregon, United States, ³Siemens Healthcare, Portland, Oregon, United States

For DCE-MRI, it is possible to obtain consistent K^trans (CR transfer constant) and v_e (extracellular, extravascular volume fraction) values whether incorporating v_b (blood volume fraction) or not into DCE-MRI modeling. This often requires minimizing the influence of v_b in DCE-MRI data time-courses.

Louisa Bokacheva¹, Ya Wang¹, Wei Huang², David M. Panicek³, and Jason A. Koutcher^1,3
1Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, NY, United States, ²Advanced Imaging Research Center, Oregon Health & Science University, Portland, OR, United States, ³Department of Radiology, Memorial Sloan-Kettering Cancer Center, New York, NY, United States

DCE MRI was performed in 34 patients with osteosarcoma and Ewing's sarcoma before, during and after neoadjuvant chemotherapy. Patients underwent surgery with histological assessment of necrosis or radiation therapy and were followed up clinically for up to six years. Voxel parameters were derived from DCE MRI data using linearized form of the Tofts model and population-based arterial input function. The mean tumor K^trans decreased significantly at the time of the third MRI session relative to baseline. Both the mean K^trans value and percent decrease relative to baseline were predictive of histological response, but did not appear to predict survival.

Ning Lang¹, Min-Ying Su², Hon J. Yu², Muqing Lin², and Huishu Yuan^1
1Department of Radiology, Peking University Third Hospital, Beijing, China, ²Center for Functional Onco-Imaging, Department of Radiological Sciences, University of California, Irvine, CA, United States

DCE-MRI was performed to differentiate between myelomas and metastatic cancers in the spine. The peak signal enhancement percentage (SE%), the steepest wash-in SE%, and the wash-out SE%, were calculated. The two-compartmental pharmacokinetic model was used to obtain Ktrans and kep. The myeloma group had a higher peak SE%, a higher wash-in and wash-out SE%, and also a higher Ktrans and kep. The ROC show that the AUC was 0.798 for Ktrans, 0.864 for kep, and 0.919 for combined Ktrans and kep. The results show that DCE-MRI may provide additional information for making differential diagnosis of spinal tumors.

Katherine L. Wright¹, Arash Aghel², Nicole Seiberlich¹, Mark A. Griswold^1,3, Anne Hamik², and Vikas Gulani^1,4
1Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio, United States, ²Case Cardiovascular Research Institute, Case Western Reserve Univ. and University Hospitals, Cleveland, Ohio, United States, ³Radiology, University Hospitals Case Medical Center, Cleveland, Ohio, United States, ⁴Radiology, Case Western Reserve University, Cleveland, Ohio, United States

Complete evaluation of both large and small vessels would typically require two separate contrast enhanced acquisitions: MR angiography and dynamic contrast enhanced (DCE) MRI. MRAP (MR Angiography and Perfusion) is a technique that allows for simultaneous acquisition of both these exams by using an optimized, 3D, time-resolved contrast-enhanced acquisition with high spatial/temporal resolution. This preliminary study applies MRAP to the clinical evaluation of peripheral arterial disease (PAD). DCE-MRI perfusion measurements from various muscles in the leg were correlated to ankle brachial index (ABI) data to evaluate the use of MRAP in PAD.

Keiko Miyazaki¹, Matthew R. Orton¹, David John Collins¹, James A. d'Arcy¹, Toni Wallace², Lucas Moreno³, Andrew Pearson³, Stergios Zacharoulis³, Martin O. Leach¹, and Dow-Mu Koh^2
1CR-UK and EPSRC Cancer Imaging Centre, The Institute of Cancer Research, Sutton, Surrey, United Kingdom, ²Department of Diagnostic Radiology, The Royal Marsden NHS Foundation Trust, Sutton, Surrey, United Kingdom, ³Department of Paediatric Oncology, The Royal Marsden NHS Foundation Trust, Sutton, Surrey, United Kingdom

The aim of this study is to investigate the feasibility and challenges of obtaining arterial input functions from paediatric DCE-MRI studies. Preliminary analysis of AIFs obtained from paediatric DCE-MRI data have shown it is possible to obtain consistent AIFs using a power injector. Inconsistencies in hand-injected AIFs found in this study have highlighted the need to optimize modes of contrast agent delivery through central lines. This is an ongoing study whereby further data will continue to be acquired in order to build a more representative paediatric population AIF that would enable quantitative DCE-MRI data analyses in paediatric clinical trial settings.

Hyunki Kim¹, Christopher Rigell¹, Guihua Zhai¹, Kyle Lee¹, Sharon Samuel¹, Amber Martin¹, Timothy Beasley¹, Long Shan Li², David Boothman², and Kurt Zinn^1
1University of Alabama at Birmingham, Birmingham, AL, United States, ²Radiation Oncology, UT Southwestern Medical Center, Dallas, TX, United States

Anti-EMMPRIN monotherapy has demonstrated strong anti-tumor effect via preventing tumor-cell invasion and neovascularization. However, care must be taken when applying anti-EMMPRIN antibody in combination with another small-molecule chemotherapeutic agent like gemcitabine, because the antiangiogenic effect of anti-EMMPRIN antibody may excessively decrease the tumor vasculature for hypovascular tumors, reducing the tumor delivery of the chemotherapeutic agent while increasing tumor hypoxia. In this study, differential therapeutic efficacy of anti-EMMPRIN antibody combined with non-targeting small-molecule chemotherapy drugs was confirmed according to tumor vascularity, and a clinical protocol to enable personalized treatment of pancreatic cancer patients based on DCE-MRI was suggested.