ECHO-PLANAR MR DETERMINATION OF RELATIVE CEREBRAL BLOOD-VOLUME IN HUMAN BRAIN-TUMORS - T1 VERSUS T2 WEIGHTING

PURPOSE: Maps related to relative cerebral blood volume (rCBV) were ge nerated with the use of the T1 effects produced by a low-dose bolus pa ssage of gadopentetate dimeglumine. The T1 maps were evaluated in a tu mor population and compared with rCBV maps obtained with T2-weighted m easurements. METHODS: Imaging was performed in 19 patients with suspec ted intraaxial brain tumors. For the T1 rCBV maps, a low-dose bolus of contrast material was given during T1-weighted interleaved spin-echo echo-planar MR imaging. This was followed by a second injection during serial T2-weighted imaging for generation of the T2 rCBV maps. RESULT S: Among patients with low-grade lesions (n = 9), T1-based and T2-base d rCBV maps showed comparably low rCBV in 7 subjects. In the other 2 p atients, with confirmed tumor dedifferentiation, elevation of rCBV val ues was seen on maps obtained with both techniques. Among patients wit h high-grade tumors (n = 10), 4 had no evidence of recurrence and 6 di d have tumor recurrence (confirmed by follow-up and positron emission tomography). In patients with the high-grade lesions exhibiting conven tional contrast enhancement, lesions tended to have higher estimated v alues on T1 rCBV maps than on the T2 rCBV maps. CONCLUSION: Although t he T1 rCBV maps showed less contrast as compared with the T2 rCBv maps , they provided diagnostic information that was comparable to the T2 r CBV maps in our series of 19 patients with primary brain tumors.