A Dynamic MR Study of the rare Hirayama’s Disease: Does Flexion Acquisition Preclude the Need of IV Contrast Study?

Abstract

Introduction: Hirayama disease (HD), is a self limiting, non hereditary, uncommon spinal cord disease affecting the forearms and hands of one or both upper limbs, due to involvement of lower cervical cord. The definitive diagnosis of Hirayama is by MRI in correlation with clinical findings and electromyography. Aim: The aim of the study was to adequately demonstrate all contributory findings to the diagnosis of HD by an MRI with neutral and flexion acquisitions. Another objective was to define and establish a standard protocol for adequate flexion technique. Lastly, to demonstrate that if adequate flexion is achieved, contrast administration becomes unnecessary. Materials and Methods: Twenty patients of clinically suspected HD presented for an MRI examination were studied. A 1.5T Philips Multiva MRI system was used. MRI was done in both neutral and flexion acquisitions and the results analysed. Results: The younger patients in their late teens and early twenties showed a progressive disease, while older patients between the ages of 27 to 34 showed a near static disease. There was a 100% positive predictive value in flexion MRI in demonstrating all the contributory findings. Neutral MRI showed loss of attachment of posterior dura in 45% cases. Cord thinning and flattening were present in all of our patients in both neutral and flexion acquisitions. Conclusion: The distinctive conclusion from this study was defining the degree and technique of flexion required to demonstrate the falling forward of the dura. By achieving this described degree of flexion, the use of intravenous Gadolinium administration is deemed unnecessary and redundant.

Keywords

• : cervical cord thinning
• cord flattening
• laminodural space
• loss of attachment of dura
• prominent epidural flow voids