TRADITIONAL POSTER - ismrm

Poster Sessions
2188. When Does Brain Motion Interfere with the Accuracy of Stereotactic Radiosurgery? Investigation of
Brain Motion in the Presence of Stereotactic Frame.
Dee H. Wu 1 , Jesse Hatfield 1 , Jignesh Modi 1 , Genu Mathew 1
1 Radiological Sciences, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
The aim of stereotactic radiosurgery is to provide accurate placement of radiation localized to targeted diseased tissues while minimizing placement of large
doses of radiation into sensitive normal tissues (such as motor strip, brain stem, internal capsule, optic nerve, and other major nerve bundles). It is well
known that the brain moves during the cardiac cycle in which the action of pulsatile blood flow produces brain expansion and contraction. Such movement
provides a potential conflict with the objective of providing millimeter to submillimeter localization accuracy of radiation treatment. This has led to
recommendations for the use of electronic gating of radiosurgery placement. While brain motion was extensively studied in the early 1990s(1, 2), and has
been a source of debate for more recent studies for the degree of head fixation required for patients for presurgical planning with fMRI (3). Such brain
motion has been cited to be on the order of 0.5 mm for controlled studies over a short period of time (minutes), to 1-3 millimeters over the course of an fMRI
experiment when standard to minimal head fixation is used (4). None of these studies were performed with such stringent fixation as that provided during
radiotherapy. The frames such that include head fixation with the insertion of metal pins attached to the patient skull with metallic frames.
2189. Image-Guided Tissue Validation of Combined Preload Dosing and Mathematical Modeling Correction
of Perfusion MRI Measures
Leland S. Hu 1,2 , Leslie C. Baxter 3 , Dilini S. Pinnaduwage 4 , Todd Jensen 5 , Amylou C. Dueck 6 , Jennifer M.
Eschbacher 7 , Joseph E. Heiserman 2 , John P. Karis 2 , Josef Debbins 3 , Jonathan Placencia Placencia 8 , Seban
Liu 3 , Burt G. Feuerstein 9 , Kathleen M. Schmainda 10
1 Radiology, Mayo Clinic, Arizona, Scottsdale, AZ, United States; 2 Radiology, Neuroradiology Section, St. Joseph's Hospital - Barrow
Neurological Institute, Phoenix, AZ, United States; 3 Keller Center for Imaging Innovation, St. Joseph's Hospital - Barrow
Neurological Institute, Phoenix, AZ, United States; 4 Radiation Oncology, University of California - San Francisco, San Francisco, CA,
United States; 5 Imaging Biometrics, LLC; 6 Biostatistics, Mayo Clinic, Arizona, Scottsdale, AZ, United States; 7 Neuropathology, St.
Joseph's Hospital - Barrow Neurological Institute, Phoenix, AZ, United States; 8 Biomedical Engineering, Arizona State University,
Tempe, AZ, United States; 9 Neuro-Oncology, St. Joseph's Hospital - Barrow Neurological Institute, Phoenix, AZ, United States;
10 Radiology, Medical College of Wisconsin, Milwaukee, WI, United States
We validate mathematical modeling correction of relative cerebral blood volume (rCBV) in regards to effectiveness of 1) minimizing T1W leakage and 2)
correcting T2/T2*W residual effects, by correlating localized measures with image-guided tissue histopathology and microvascular density from stereotactic
biopsies in post-treatment high-grade gliomas.
2190. Automatic Segmentation of Optic Pathway Gliomas Using Multiparametric Mri Methods
Liat Ben Sira 1 , Lior Weizman 2 , Leo Joskowicz 2 , Ronit Precel 1 , Shlomi Constantini 3,4 , Dafna Ben Bashat 5
1 Department of Radiology , Tel Aviv Sourasky Medical Center, Tel-Aviv, Israel; 2 School of Eng and Computer Science, The Hebrew
Univeristy of Jerusalem, Jerusalem, Israel; 3 The Paediatric Neurosurgery Department, Tel Aviv Sourasky Medical Center, Tel-Aviv,
Israel; 4 Sackler Faculty of Medicine, Tel Aviv University, Tel-Aviv, Israel; 5 The Wohl Institute for Advanced Imaging, Brain Imaging
Center, Tel Aviv Sourasky Medical Center , Tel-Aviv, Israel
Accurate and consistent volumetric measurements of optic pathway gliomas (OPG), the most common tumor in the brain in patients with Neurofibromatosis,
are clinically crucial. In this study we present an automatic method for segmentation of OPGs from multi-spectral MRI datasets. The method effectively
incorporates prior location of the OPG, its shape and intensity and accurately identifies the boundaries in a consistent and repeatable manner. The method
was tested on 15 data sets, the optimal threshold was derived from a receiver operating characteristic curve, and a significant correlation was obtained
between the volume calculated using this method compared to manual measurements.
2191. Translational Methods for Retrospective Long Term Evaluation of Cancer with MRS
Dee H. Wu 1 , Levi Garrett 1 , Jignesh Modi 1 , Bowei Han 1 , Hans Cao 1
1 Radiological Center, University of Oklahoma Health Sciences Center, Edmond, OK, United States
We have created a procedure for retrospective review of digitized MRS images that permits fundamental baseline removal and frequency bracketing with
the target of creating a user-friendly tool. This newly created clinical workflow will improve long term care for patients that may require important
decisions pertaining to whether the status of a tumor has changed (such as tumor reoccurrence or remission). A central concept is that we have also
conducted tolerance testing in which common confounds to artifacts that arise from shimming, electronic noise, field inhomogenity, coil sensitivities,
relaxation.
2192. MR Biomarkers of Tyrosine Kinase Inhibition in Mouse Gliomas
Paul A. Schornack 1 , Jia-Jean Yiin, Bo Hu, Raghvendra S. Sengar, Ken-Wei Liu, Haizhong Feng, Frank S.
Lieberman, Jann N. Sarkaria 2 , Erik Wiener, Hsin-I Ma 3 , Shi-yuan Cheng
1 Radiology, University of Pittsburgh, Pittsburgh, PA, United States; 2 Mayo Clinic; 3 Taiwan National Defense Medical Center
We present a comparison of MR techniques sensitive to T2, T2*, & ADC to measure mouse gliomas & correlate with histology. We compare untreated
mice with mice treated with an anti-angiogenic agent, ZD6474 (Zactima, vandetanib), a dual inhibitor of VEGFR2 & EG. ZD6474 significantly inhibited
growth & angiogenesis of gliomas expressing EGFRvIII by specifically blocking signaling transducers in brain, which suggests a potential application in
treatments for gliomas that overexpress this factor. Our results indicate that susceptibility/T2* weighted MR along with ADC and T2 measurements can be
used as a means of non-invasively quantifying the efficacy of such treatment protocols.