Lumbar Radiculopathy - Incremental Value of Magnetic Resonance Neurography over Non-Contributory Magnetic Resonance Imaging.

Dear Editor, Lumbar radiculopathy is defined in terms of symptoms (including pain and paraesthesia) and signs (including weakness) in the distribution of a spinal nerve root. Compression of the nerve root, possibly leading to inflammation, is a common aetiology. Magnetic resonance imaging (MRI) is the preferred imaging modality used for evaluation of patients with lumbar radiculopathy. It serves as a useful adjunct to electrodiagnostic testing, which include electromyography (EMG) and nerve conduction studies. MRI has been shown to provide excellent inter-observer agreement for the diagnosis of nerve root compression in patients with radiculopathy.1 However, a management dilemma frequently occurs when a patient with clinical features of radiculopathy has normal or non-contributory MRI findings. In this article, we report a patient with Parkinson’s disease who presented with features of lumbar radiculopathy and subsequently underwent MRI lumbar spine examination, which was inconclusive. The final diagnosis was made using high resolution magnetic resonance neurography (MRN) of the lumbosacral plexus, which employed 2-dimensional (2D) and isotropic 3D imaging sequences. Case Report A 78-year-old male, previously diagnosed with Parkinson’s disease, presented to the clinic with progressive gait disturbance. He had a history of twisting his back 1 week prior and thereafter, developed left leg weakness and radicular pain radiating from his back to his groin and left hip. On examination, there was weakness on left hip flexion, left knee extension and absence of left knee jerk. Left lumbar radiculopathy was clinically suspected to be the cause of his gait dysfunction, but progression of his Parkinson’s disease could not be ruled out as being responsible for the above findings. MRI of the lumbar spine performed outside reported multilevel disc herniations and was inconclusive of nerve compression. MRN was performed on 3.0T MR scanner (Achieva, Philips, Best, Netherlands) using 2D axial T1W, axial T2W Dixon, 3D SHINKEI (nerve-sheath signal increased with INKed rest-tissue RARE Imaging) and diffusion tensor imaging (DTI) techniques. The study showed an extruded paracentral disk fragment arising from L3-L4 disc space on the left, extending inferiorly into the spinal canal behind the L4 vertebral body (Fig. 1), and small disc herniations at other levels. The mass effect was clearly depicted on