Synthetic versus conventional MRI for ring-enhancing brain lesions: A pre- and post-contrast comparison

Synthetic MRI has potential to significantly reduce MR scan time by reconstructing multiple contrast images from a single acquisition. The aim of this study was to compare the image quality of both pre- and post-contrast synthetic MRI in subjects with ring-enhancing brain lesions with conventional images. 50 patients with radiologically confirmed ring-enhancing brain lesions underwent TSE_MDME sequence before and after gadolinium administration along with conventional MRI sequences. Image quality was compared between synthetic and conventional sequences on a 4-point scale across 5 parameters, that is, grey white matter differentiation, demarcation of caudate nucleus, lentiform nucleus, demarcation of sulci, and SNR. Also, the artefacts, lesion conspicuity, and ability to diagnose on synthetic images were studied. Image quality of synthetic MRI was relatively similar across all sequences except for FLAIR. The image quality comparison between synthetic and conventional images showed an agreement in 70.7% of the cases (Weighted Kappa = 0.043, p = <0.001). Artefacts were maximum in synthetic FLAIR sequence (52%). 50% cases showed a discordant enhancement pattern in post contrast synthetic images. Despite a higher occurrence of artefacts in synthetic post contrast images, diagnostic ability was comparable across pre- and post-contrast synthetic and conventional images. Synthetic MRI provides comparable diagnostic quality of images with acceptable rate of artefacts in both pre and post contrast sequences. However, needs a careful interpretation especially when diagnosis is heavily relied on the enhancement pattern of lesions.