Multi-contrast, isotropic, single-slab 3D MR imaging in multiple sclerosis

Abstract

To describe signal and contrast properties of an isotropic, single-slab 3D dataset [double inversion-recovery (DIR), fluid-attenuated inversion recovery (FLAIR), T2, and T1-weighted magnetization prepared rapid acquisition gradient-echo (MPRAGE)] and to evaluate its performance in detecting multiple sclerosis (MS) brain lesions compared to 2D T2-weighted spin-echo (T2SE). All single-slab 3D sequences and 2D-T2SE were acquired in 16 MS patients and 9 age-matched healthy controls. Lesions were scored independently by two raters and characterized anatomically. Two-tailed Bonferroni-corrected Student's t-tests were used to detect differences in lesion detection between the various sequences per anatomical area after logtransformation. In general, signal and contrast properties of the 3D sequences enabled improved detection of MS brain lesions compared to 2D-T2SE. Specifically, 3D-DIR showed the highest detection of intracortical and mixed WM-GM lesions, whereas 3D-FLAIR showed the highest total number of WM lesions. Both 3D-DIR and 3D-FLAIR showed the highest number of infratentorial lesions. 3D-T2 and 3D-MPRAGE did not improve lesion detection compared to 2D-T2SE. Multi-contrast, isotropic, single-slab 3D MRI allowed an improved detection of both GM and WM lesions compared to 2D-T2SE. A selection of single-slab 3D contrasts, for example, 3D-FLAIR and 3D-DIR, could replace 2D sequences in the radiological practice.

Comparison of 3D Cube FLAIR with 2D FLAIR for Multiple Sclerosis Imaging at 3 Tesla

“…3 D sequences have the advantage of good signal and contrast properties despite the small voxels. High SNRs and CNRs have been described for 3 D FLAIR sequences [17,18]. These findings are confirmed by our measurements, which showed higher values for all calculated ratios except for the CNR lesion GM.…”

“…Analyzing the Cube images, only four lesions were described as mixed gray/white matter (one in the 2 D FLAIR) and none was located clearly intracortically. Again a definite conclusion cannot be drawn from this small study, yet these findings are in accordance with the results of Moraal et al who found significantly lower numbers of intracortical lesions with a 3 D FLAIR sequence than with a 3 D double inversion recovery (DIR) sequence [17,18]. It may well be possible that Cube FLAIR improves detection of supratentorial white matter lesions while different sequences are necessary for optimized imaging of the infratentorial and cortical regions.…”

“…These drawbacks were extinguished by the introduction of single-slab sequences [16]. More recently, single-slab 3 D FLAIR sequences were tested and compared to 2 D sequences in MS imaging and were shown to be highly sensitive in lesion detection [17,18]. To our knowledge, the 3 D "Cube" sequence has not yet been tested for this purpose and there is only one study comparing 3 D and 2 D FLAIR sequences regarding MS lesions at 3 T [18].…”

“…More recently, single-slab 3 D FLAIR sequences were tested and compared to 2 D sequences in MS imaging and were shown to be highly sensitive in lesion detection [17,18]. To our knowledge, the 3 D "Cube" sequence has not yet been tested for this purpose and there is only one study comparing 3 D and 2 D FLAIR sequences regarding MS lesions at 3 T [18]. In our setup, 74 % more lesions could be detected by implementing the three-dimensional Cube FLAIR sequence than by using the standard two-dimensional FLAIR sequence.…”

The Technical and Clinical Features of 3D-FLAIR in Neuroimaging

“…For 3D-FLAIR, there are many reports regarding application to multiple sclerosis. 5,6,[42][43][44][45][46][47][48][49][50][51][52][53][54] Smaller lesions can be detected by 3D-FLAIR than by 2D-FLAIR due to thinner slices and fewer flow artifacts with 3D-FLAIR. 45,46 Excellent detection of cortical lesions by 3D-FLAIR has also been reported (Fig.…”