In the recent time, the sequence used to delineate gray matter lesions is Double Inversion Recovery (DIR), with the use of this sequence in high magnetic field (3 Tesla machine).
To detect and localize gray matter lesions in patients with established multiple sclerosis using DIR sequence in 3 Tesla MRI. Also to compare the detection rate of white matter lesions by the use of DIR versus Fluid Attenuation Inversion Recovery (FLAIR) sequence.
PATIENTS AND METHODS:
A prospective study included 54 patients with established diagnosis of multiple sclerosis of more than 3 years duration was conducted from April 2014 to January 2015. The study was done in the MRI units of Al-Yarmouk Teaching Hospital and Al-Imamian Al-Kadhimian Medical City. All patients were examined with the following MRI imaging sequences: T2WI axial, T2 FLAIR sagittal and coronal, T1 axial and sagittal, DIR axial and coronal. T1 Sagittal and axial were repeated after giving IV contrast and examined after 30 minutes postcontrast. Gray matter lesions were classified according to Peterson and Bo model. Statistical analysis conducted by using Excel 2013 version.
Fifty four patients with established diagnosis of MS (43 patients with relapsing remitting MS and 11 patients with secondary progressive MS) were included. Of the 54 patients, 39 patients (72.2%) patients have positive gray matter lesion. The 39 patients with positive gray matter lesions are classified as follows: 26 patients (66.5%) had sub-pial lesions, 9 patients (23%) had leucocortical lesions, 3 patients (7.5%) showed entirely cortical lesions, and finally the whole cortex is involved in 1 patient only (2.5%). The insular cortex was the most commonly involved region seen in 14 patients (35.8%), followed by the thalamic lesions. Among the 39 patients with positive 9 patients (16.5%) had additional deep nuclei lesions. Total number of lesions detected by DIR (320 lesions) was largely greater than the total number of lesions detected by FLAIR (185 lesions).
DIR is a sensitive sequence for detection of gray matter lesion, DIR is more sensitive than FLAIR in detection of white matter lesions and cortical gray matter lesions are more commonly encountered than deep nuclei lesions.