[Comparison of gradient echo and echo planar imaging measurements for the calculation of regional blood volume maps]

The purpose of this study was to evaluate relative regional blood volume (rCBV) in meningioma and compare the utility of reconstruction using both gradient-echo sequence and echo-planar-imaging (EPI) sequence. Eighteen patients with meningiomas were studied on a Siemens 1.5-T scanner. During the gradient-echo sequence (n=12) and EPI sequence (n=6), a bolus (0.2 mmol/kg) of Gd-DTPA was injected mechanically with a flow rate of 5 ml/second. Image processing of dynamic data was performed on a pixel-by-pixel basis. The ratio of tumor rCBV/gray matter rCBV was 3.01 +/- 1.18 (3.07 +/- 1.39 in gradient sequence and 2.84 +/- 0.94 in EPI sequence). The ratio of gray matter/white matter as the reference tissue had a mean of 2.79 +/- 0.76 using the FLASH sequence, and a mean of 3.04 +/- 1.31 using EPI. These differences were not statistically signifcant (P>0.5, t-test). According to the ratio of tumor rCBV/gray matter rCBV, a mean value, 14.5 ml/100 g, of rCBV in meningiomas was calculated. Compared with gray matter, increased inhomogeneous rCBV was observed in meningioma. Based on the two different sequences, no bias can be observed in our rCBV reconstruction.