NIMG-26COMPARISON OF POST-GADOLINIUM 3D FAST SPIN ECHO IMAGES VERSUS REGISTERED AND SUBTRACTED MPRAGE IMAGES IN GLIOMA PATIENTS

Abstract

BACKGROUND: Multiple 3D MRI methods can show contrast enhancement. One option is to acquire Magnetization-Prepared Rapid Gradient Echo (MPRAGE) images before and after gadolinium administration, register them, and subtract. Another option is to acquire only post-contrast images with high sensitivity to contrast, as with CUBE (GE Medical Systems) and SPACE (Siemens Medical Systems), grouped here as Fast Spin Echo (FSE). To our knowledge, no comparison of MPRAGE vs FSE has been performed. METHODS: IRB waived requirement for consent. For a period of 4 weeks (total 64 glioma patients), we prospectively collected MPRAGE images before and after contrast administration, as well as CUBE or SPACE images after gadolinium. Imaging was performed at 3T in all cases, on either Siemens or GE scanners. The pixel resolution was 1mm3. After contrast administration, a T2-weighted series was acquired and then FSE or MPRAGE followed by the other (order was randomly assigned). After acquisition, the MPRAGE images were registered, and then subtracted. All four images (FSE, Subtraction, MPRAGE Pre, and MPRAGE Post) were presented to 3 trained neuroradiologists. They were asked to provide a rating from 1-5 (1 = FSE definitely more apparent, 2 = probably, 3 = same, 4 = subtraction probably better, 5 = subtraction definitely more apparent). Signed rank tests, a non-parametric alternative to the paired t test, were used to test for differences between the two methods. RESULTS: FSE images better showed contrast enhancement for 2 of 3 individuals (p = 0.02, 0.004, 0.2) as well as the mean ratings over the 3 readers (p < 0.0006). In one case, all three readers agreed there was enhancement on FSE not seen on subtraction. In no case did all 3 readers agree the subtraction was better. In 30/64 cases, all three readers reported there was no difference in enhancement. CONCLUSIONS: 3D FSE images may be or more sensitive to contrast enhancement than registration/subtraction.