Comparison of Cerebral Blood Volume Measurements Using the T1 and T2* Methods in Normal Human Brains and Brain Tumors

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Abstract
Regional cerebral blood volume (rCBV) can be determined after bolus injection of a contrast agent by utilizing the susceptibility effect(T2* method) or the relaxation effect (T1 method). The aim of this study was to apply both methods in groups of normal subjects and tumor patients and to compare the results. CBVs in different brain areas were determined from groups of 18 normal subjects and 21 patients with different histologically classified tumors. Measurements were performed using GE sequences on a 1.5 T scanner without echo planar imaging capability. As a measure of quality of a single examination, the temporal behavior of the contrast agent bolus was characterized using parameters such as rise time, peak value, fall time, and full width at half-maximum of the concentration-time curves. The quality of the T2* measurements was inferior to that obtained with the T1 method. A mean CBV value of 4.1 ± 1.1 vol% averaged over the entire brain area was found in the normal collective with the T1 method. The value obtained with the T2* method was 2.6 ± 1.1 vol%. Similar underestimations of the CBV values were also found using the T2* method when evaluating regions of interest in tumor patients. Both methods are able to determine rCBV in routine clinical studies. If the goal is to obtain quick, qualitative multislice information, the T2* method is adequate. For quantitative evaluations, however, the T1 method should be preferred.