Highly accelerated knee magnetic resonance imaging using deep neural network (DNN)-based reconstruction: prospective, multi-reader, multi-vendor study.

In this prospective, multi-reader, multi-vendor study, we evaluated the performance of a commercially available deep neural network (DNN)-based MR image reconstruction in enabling accelerated 2D fast spin-echo (FSE) knee imaging. Forty-five subjects were prospectively enrolled and randomly divided into three 3T MRIs. Conventional 2D FSE and accelerated 2D FSE sequences were acquired for each subject, and the accelerated FSE images were reconstructed and enhanced with DNN-based reconstruction software (FSE-DNN). Quantitative assessments and diagnostic performances were independently evaluated by three musculoskeletal radiologists. For statistical analyses, paired t-tests, and Pearson's correlation were used for image quality comparison and inter-reader agreements. Accelerated FSE-DNN reduced scan times by 41.0% on average. FSE-DNN showed better SNR and CNR (p < 0.001). Overall image quality of FSE-DNN was comparable (p > 0.05), and diagnostic performances of FSE-DNN showed comparable lesion detection. Two of cartilage lesions were under-graded or over-graded (n = 2) while there was no significant difference in other image sets (n = 43). Overall inter-reader agreement between FSE-conventional and FSE-DNN showed good agreement (R2 = 0.76; p < 0.001). In conclusion, DNN-based reconstruction can be applied to accelerated knee imaging in multi-vendor MRI scanners, with reduced scan time and comparable image quality. This study suggests the potential for DNN-accelerated knee MRI in clinical practice.

MRI Findings of Isolated Oculomotor Nerve Palsy after Mild Head Trauma in a Pediatric Patient: Case Report.

INTRODUCTION: Traumatic oculomotor nerve injury is usually caused by severe head trauma and is generally associated with other neurological deficits such as basilar skull fracture, orbital injury, or subarachnoid hemorrhage. Isolated traumatic oculomotor nerve injury after minor head trauma and its MRI findings are rarely reported. CASE PRESENTATION: We report a case of a 13-year-old girl with mydriasis, limited inferior and medial movement of the left eyeball, and left ptosis after a mild bump of the left forehead and eye into an electricity pole. The symptoms suggested left oculomotor nerve palsy, but initial facial computed tomography and brain MRI did not reveal any intracranial lesions or fractures in the skull and orbit. Cranial nerve MRI showed segmental hyperintensities and mild thickening of the left oculomotor nerve from the cavernous segment to the proximal orbital segment on T2 short tau inversion recovery and 3D fluid-attenuated inversion recovery volume isotropic turbo spin-echo acquisition sequences. The patient received treatment with oral pyridostigmine for 7 days and was fully recovered at 14 months after injury. DISCUSSION: As traumatic oculomotor nerve palsy can occur without intracranial hematomas or skull base fractures, routine brain MRI may not always reveal abnormalities; thus, MRI dedicated to imaging of the oculomotor nerve using FS T2WI and high-resolution 3D sequences can be helpful for the diagnosis and management of patients suspected of isolated oculomotor nerve injury.