Efficacy of PROPELLER in reducing ocular motion artefacts and improving image quality of orbital MRI at 3 T using an eye surface coil

Abstract

To evaluate the efficacy of periodically rotated overlapping parallel lines with enhanced reconstruction (PROPELLER) in reducing ocular motion artefacts and improving image quality of orbital magnetic resonance imaging (MRI) at 3 T using an eye surface coil. Forty-six patients underwent orbital 3 T MRI using an eye surface coil. The pre-contrast axial T2-wighted (W) PROPELLER and T1 fluid-attenuated inversion recovery (FLAIR) PROPELLER imaging were performed on 21 patients, and conventional T2W and T1W imaging were performed on 25 patients. The ocular motion artefacts, delineation of anatomical structures, depiction of lesions, and image quality were evaluated independently by two radiologists using a five-point scale. The signal-to-noise ratios (SNRs) of anatomical structures and lesions were measured. The interobserver agreement was good to excellent (kappa values from 0.79 to 0.91). PROPELLER sequences had higher scoring than the conventional sequences in all cases (p<0.05). PROPELLER images showed fewer motion artefacts, higher image quality, and more clear delineation of anatomical structures and lesions than the non-PROPELLER images. T2W PROPELLER images produced higher SNRs in lens, vitreous body, lacrimal gland, and lesions than conventional T2W images (p<0.05). T1 FLAIR PROPELLER images showed lower SNRs in lens, vitreous body, medial rectus, lateral rectus, temporalis, and posterior half of optic nerve than conventional T1W images (p<0.05). PROPELLER can effectively reduce ocular motion artefacts and improve image quality, which plays an important role in clearly delineating anatomical structures and lesions on orbital 3 T MRI using an eye surface coil.