title: MRI findings in Hirayama disease.
abstract: The objective of the study was to study the magnetic resonance imaging (MRI) features of Hirayama disease on a 3 Tesla MRI scanner. Nine patients with clinically suspected Hirayama disease were evaluated with neutral position, flexion, contrast-enhanced MRI and fast imaging employing steady-state acquisition (FIESTA) sequences. The spectrum of MRI features was evaluated and correlated with the clinical and electromyography findings. MRI findings of localized lower cervical cord atrophy (C5-C7), abnormal curvature, asymmetric cord flattening, loss of attachment of the dorsal dural sac and subjacent laminae in the neutral position, anterior displacement of the dorsal dura on flexion and a prominent epidural space were revealed in all patients on conventional MRI as well as with the dynamic 3D-FIESTA sequence. Intramedullary hyperintensity was seen in four patients on conventional MRI and on the 3D-FIESTA sequence. Flow voids were seen in four patients on conventional MRI sequences and in all patients with the 3D-FIESTA sequence. Contrast enhancement of the epidural component was noted in all the five patients with thoracic extensions. The time taken for conventional and contrast-enhanced MRI was about 30-40 min, while that for the 3D-FIESTA sequence was 6 min. Neutral and flexion position MRI and the 3D-FIESTA sequence compliment each other in displaying the spectrum of findings in Hirayama disease. A flexion study should form an essential part of the screening protocol in patients with suspected Hirayama disease. Newer sequences such as the 3D-FIESTA may help in reducing imaging time and obviating the need for contrast.
authors.affiliation: Department of Neuroradiology, Institute of Human Behaviour and Allied Sciences (IHBAS), Delhi, India.
authors.forename: Monali
authors.initials: M
authors.lastname: Raval
authors.forename: Rima
authors.initials: R
authors.lastname: Kumari
authors.forename: Aldrin Anthony Dung
authors.initials: AA
authors.lastname: Dung
authors.forename: Bhuvnesh
authors.initials: B
authors.lastname: Guglani
authors.forename: Nitij
authors.initials: N
authors.lastname: Gupta
authors.forename: Rohit
authors.initials: R
authors.lastname: Gupta