Comparison of cerebral blood volume measurements using the T1 and T2* methods in normal human brains and brain tumors

Purpose: 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. Method: 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 rime, and full width at half-maximum of the concentration-time curves. Results: 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. Conclusion: 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.