Rainald Bachmann MD, PRESENTER: Nothing to Disclose

Abstract: HTML Purpose: To date few comparative studies have evaluated the impact of high-field MRI in clinical routine settings. The purpose of this prospective study was to compare the diagnostic efficacy of high-field 3T MRI in comparison to conventional 1.5T MRI in patients with proven multiple sclerosis. Methods and Materials: 11 consecutive patients (3 m, 8 f, mean age 38 yrs) were examined within three days at a 1.5 and 3.0T system (Gyroscan Intera, Philips Medical Systems). Sequence protocols were modified for 3T using the increased SNR to acquire more and thinner slices within comparable scan times (3T: 27 slices, 4 mm; 1.5T: 20 slices, 6 mm). Imaging protocols consisted of axial FLAIR, sagittal FLAIR, axial T2w-TSE, axial T1w-FFE (3T) and axial T1w-SE (1.5T). FLAIR-images of either field strength were ranked for each patient qualitatively in matched pairs by two observers with regard to artifacts, gray-white differentiation, image noise, lesion conspicuity and overall diagnostic value. SI-measurements were obtained in gray and white matter, CSF and representative white matter lesions (WML). Total number of lesions detected was noted for each field strength. Statistical significance was determined by Wilcoxon signed-ranks test and Student t-test. Results: Regarding the qualitative assessment 3T was judged superior to 1.5T for lesion conspicuity (p<0.0009) and overall diagnostic value (p<0.008), whereas no difference was found for gray-white differentiation and image noise. 3T was inferior to 1.5T with regard to artifacts. SNR of CSF was lower at 3T (8.1 vs 11.3, p<0.05), but CNR for WML was not different at both field strength (19.6 vs 19.3). However, significantly more WML were detected at 3T than at 1.5T (162 vs 117, p<0.0007). Conclusion: High-field 3T MRI is superior to 1.5T in terms of lesion detection. Trading of higher SNR at 3T for better spatial resolution the same CNR level can be maintained, thus increasing lesion detectability. Despite intensified artifacts, overall diagnostic value is superior to 1.5T. Thus, high field MRI may further strengthen the role of MRI as the most sensitive paraclinical test available for early diagnosis of multiple sclerosis.      

Bachmann MD, R, Multiple Sclerosis: Comparative MR-Imaging at 1.5 and 3.0 Tesla.  Radiological Society of North America 2003 Scientific Assembly and Annual Meeting, November 30 - December 5, 2003 ,Chicago IL. http://archive.rsna.org/2003/3107515.html