In primary studies with 3 T Magnets, phase sensitive reconstruction of T1-weighted inversion recovery (PSIR) have showed ability to depict the cervical multiple sclerosis (MS) lesions some of which may not be detected by short tau inversion recovery (STIR). Regarding to more availability of 1.5 T MRI, this study was designed to evaluate the eligibility of PSIR in 1.5 T for detection of spinal cord MS lesions.
Method: In a prospective study between September 2016 till March 2017 the patients with proven diagnosis of MS enrolled to the study. The standard protocol (sagittal STIR and T2W FSE and axial T2W FSE) as well as sagittal PSIR sequences were performed using a 1.5 T magnet. The images were studied and the lesions were localized and recorded as sharp or faint on each sequence. Also normalized contrast between lesion and normal-appearing spinal cord was measured for each sequence.
Of 25 patients (22 females and 3 males, with mean age of 33.5 ± 9.8 years and mean disease duration of 5.4 ± 3.9 years) 69 lesions in STIR, 53 lesions in T2W FSE, 47 lesions in Magnitude reconstruction of PSIR (Magnitude), and 30 lesions in phase sensitive (real) reconstruction PSIR were detected. A Wilcoxon signed-rank test showed STIR has a statistically significant higher detection rate of the plaques rather than other three sequences. T2W FSE and Magnitude both had a statistically significant superiority in detection of the plaques rather than real PSIR. STIR had a statistically significant difference in the boundary definition of the plaques rather than other three sequences. There was no statistically significant difference in the boundary definition of the plaques between Magnitude and real reconstructions. The mean of normalized lesion-to-cord signal on STIR, T2FSE, Magnitude and real reconstructions were 49.54 ± 18.46, 35.40 ± 25.68, 85.61 ± 47.07, 103.05 ± 47.01 percent, respectively.
This study shows that in the setting of a 1.5 T magnet field, STIR significantly has a superiority over both of the PSIR reconstructions (i.e. real and magnitude) for the detection as well as the boundary definition of the cervical cord lesions of MS. This result is in contrast with other reports performed by 3T Magnet fields. It should be mentioned in Magnims protocol that PSIR reconstructions can be an alternative of STIR only in 3T.