Parinaz Massoumzadeh PhD, Presenter: Nothing to Disclose

Xiang He, Abstract Co-Author: Nothing to Disclose

Sarah C. Jost MD, Abstract Co-Author: Nothing to Disclose

Keith M Rich MD, Abstract Co-Author: Nothing to Disclose

Dmitriy A. Yablonskiy PhD, Abstract Co-Author: Nothing to Disclose

Tammie Smith Benzinger MD, PhD, Abstract Co-Author: Speakers Bureau, Siemens AG Travel support, Siemens AG

The main objective of this study is to evaluate the feasibility of using a recently developed MR technique, quantitative blood oxygenation level-dependent (qBOLD), to quantify the oxygen extraction fraction (OEF) of tumors metastatic to the brain.

The qBOLD technique provides a regional OEF measurement based upon an MR signal model of brain that incorporates prior knowledge about brain tissue composition. A 3D version of gradient echo sampling of spin echo sequence with RF spoiling is used to obtain the MRI signal. (He, Zhu, and Yablonskiy, MRM 60:4, 882-888, 2008). To evaluate the feasibility of qBOLD quantify OEF in central nervous system tumors, seven patients (47.9 y to 69.2 y, mean 56.1y, 4 female and 3 male) with metastatic brain tumors were prospectively enrolled in a longitudinal imaging study. The primary malignancies were lung cancer (in six patients) and renal cell carcinoma (in one patient). The qBOLD procedure was performed as part of an integrated neuroimaging protocol, including conventional pre- and post-contrast images and dynamic susceptibility contrast perfusion. The patients were scanned at 1.5T (Siemens TIM Espree) while wearing a stereotactic frame prior to radiation therapy. Tumor volume ranged from 174 mm3 to 4500 mm3 (mean 1440 mm3). Radiation doses were ranged from 15 Gy to 48 Gy (mean 28.6 Gy), whith the 50% line dose level of 18 Gy to 24 Gy (mean 20.3 Gy), and the radiation time ranged from 18 min to 79 min (mean 35 min). Post processing was performed offline using Matlab.  

Supratentorial metastatic tumors (7 patients) and surrounding vasogneic edema demonstrated marked visual conspicuity and quantifiably altered OEF using the qBOLD MRI: e.g, OEF values for the area of vasogenic edema were 54.8+/-12.3 % compared to 36.6+/-6.6 % in contralateral normal white matter.

Using a recently developed MR pulse sequence, qBOLD, we were able to quantify the OEF in humans with metastatic brain tumors. qBOLD offered excellent visual conspicuity for lesion detection for supratentorial, non-hemorrhagic lesions. Interestingly, vasogenic edema surrounding metastatic tumors was also associated with elevated OEF, a finding which warrants further investigation.

By measuring tumoral and peritumoral brain tissue OEF by MR methods we may be better able to predict patients' responses to radiation treatment in the future.

Massoumzadeh, P, He, X, Jost, S, Rich, K, Yablonskiy, D, Benzinger, T, Quantitative Measurement of Hypoxia in Human Brain Tumors Using qBOLD MRI.  Radiological Society of North America 2009 Scientific Assembly and Annual Meeting, November 29 - December 4, 2009 ,Chicago IL. http://archive.rsna.org/2009/8014956.html