Clinical evaluation of white matter lesions on 3D inversion recovery ultrashort echo time MRI in multiple sclerosis.

Abstract

We clinically evaluated the quality of white matter lesions (WML) of the cerebrum on 3D inversion recovery ultrashort echo time (IR-UTE) magnetic resonance imaging (MRI) in multiple sclerosis (MS) patients. Forty-nine patients with MS were included in this study. A 3T MRI scanner was used. Two radiologists (readers) evaluated the quality of WML on IR-UTE images using a three-point Likert scale (1-good quality, 2-moderate quality, 3-insufficient quality). They also rated other WML-related factors potentially influencing WML quality using another three-point Likert scale (1-no/minor impact, 2-moderate impact, 3-high impact). Another reader rated the presence of WML on IR-UTE to evaluate the diagnostic value (right/false positive and false negative) of IR-UTE in detecting WML. Signal intensity ratios (SIRs) derived from WML signal intensities and WML sizes were also determined and analyzed. Two hundred and seventy-five MS lesions were evaluated. 87% of the lesions were rated Likert 1 on IR-UTE (P<0.01). WML rated Likert 2 and 3 presented near the grey matter (GM) in 58% of the cases (n=21), with 14 lesions being ≤2 mm (P=0.03). 62.5% of the WML rated Likert 2/3 were in the temporal lobe (P=0.02). The mean SIR of WML on IR-UTE was 1.14±0.22, while the mean SIR on fluid-attenuated inversion recovery (FLAIR) was 6.97±1.88. There was no significant correlation of SIRs between IR-UTE and FLAIR (R=0.14, P=0.245). 92.4% of the WML were correctly detected on IR-UTE (n=254). 19 out of the 21 false positive/negative rated WML were located near the GM or in the temporal lobe. WML presented 7.7% smaller in mean on IR-UTE compared to FLAIR. Factors affecting WML quality with a moderate or high impact (Likert 2 and 3) were not found. Most WML are clearly detectable on IR-UTE sequences. The main limitations are WML in the temporal lobe and near the GM.