COMPARISON OF CEREBRAL BLOOD-VOLUME MEASUREMENTS USING THE T1 AND T2-ASTERISK 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 e ffect (T2 method) or the relaxation effect (T1 method). The aim of th is study was to apply both methods in groups of normal subjects and tu mor patients and to compare the results. Method: CBVs in different bra in areas were determined from groups of 18 normal subjects and 21 pati ents with different histologically classified tumors. Measurements wer e performed using GE sequences on a 1.5 T scanner without echo planar imaging capability. As a measure of quality of a single examination, t he temporal behavior of the contrast agent bolus was characterized usi ng parameters such as rise time, peak value, fall rime, and full width at half-maximum of the concentration-time curves. Results: The qualit y of the T2 measurements was inferior to that obtained with the T1 me thod. A mean CBV value of 4.1 +/- 1.1 vol% averaged over the entire br ain area was found in the normal collective with the T1 method. The va lue obtained with the T2 method was 2.6 +/- 1.1 vol%. Similar underes timations of the CBV values were also found using the T2 method when evaluating regions of interest in tumor patients. Conclusion: Both met hods are able to determine rCBV in routine clinical studies. If the go al is to obtain quick, qualitative multislice information, the T2 met hod is adequate. For quantitative evaluations, however, the T1 method should be preferred.