The effect of cross-talk on MRI lesion numbers and volumes in multiple sclerosis using conventional and turbo spin-echo

We measured and compared lesion numbers and volumes present on brain magnetic resonance imaging (MRI) scans of patients with multiple sclerosis (MS) acquired with contiguous (scheme A) and interleaved (scheme B) slice acquisition, to evaluate whether there was a gain in sensitivity using the second pattern of acquisition and whether this counterbalanced the doubled acquisition time. Conventional spin-echo (CSE) sequences were performed for eight patients and turbo spin-echo (TSE) sequences for ten. Acquisition scheme B detected 3.8% more lesions than acquisition scheme A (the increase was 3.1% for CSE and 4.5% for TSE). These differences were not statistically significant. No significant difference in lesion numbers was found when different lesion locations were also considered. Lesions volumes were significantly higher when scheme B was used (P = 0.024). This was due to higher lesion volumes on TSE images (P = 0.006), especially on even-numbered slices (P = 0.008). Inter-slice cross-talk has a negligible effect on lesion numbers and volume estimates in MS for CSE sequence, whilst it cannot be neglected when TSE sequences are used to measure MS lesion volume.