Magnetic Resonance Diagnostics of Diabetic Peripheral Neuropathy

Background

Diabetes mellitus is a very frequent disorder with an estimated prevalence of 275,000 patients in Denmark. Diabetic peripheral neuropathy (DPN) is a late complication which often remains undiagnosed, but may occur in up to 40% of diabetic patients. Advanced neuropathy may induce irreversible damages to the nervous tissue, and to avoid further damages, early diagnosis is important followed by optimal treatment of diabetes. DPN is a common complication due to long term diabetes in both type 1 and type 2.

Nerve conduction studies (NCS) is the gold standard method to diagnose DPN. However, the technique is time consuming and introduces discomfort to the patient and, furthermore, early nerve dysfunction may not be detected by NCS. Magnetic resonance imaging (MRI) (3 Tesla) of peripheral nerves is a new technique entitled Magnetic resonance neurography (MRN). In recent studies MRN has documented morphological changes in individual nerve fascicles. In T2-weighted images hyperintensity is present in proximal parts of nerves from neuropathic patients as compared to healthy nerves. This hyperintensity is believed to reflect early and more widespread lesions to the nerve fascicles that are not detected by NCS. This is pointing towards MRN to become an important tool in the management of patient with peripheral neuropathies.

Recent technical development such as diffusion weighted imaging (DWI) and diffusion tensor imaging (DTI) are currently being evaluated for imaging of the peripheral nerve system. DTI is expected to provide information about the physiology of the nerves and may reveal vascular congestion such as; blockade of axoplasmic flow, leading to abnormal proximal accumulation of endoneurial fluid; and distal Wallerian degeneration changes. Fiber tracking used on DTI is clinically implemented in some cases of stroke, tumours, neuropathy surgery, and functional brain MR imaging. Additionally, fiber tracking has been used on neuropathic patients with carpal tunnel syndrome, but has yet to be used in DPN as a measure of physiological function of the peripheral nerves.

Investigator, sponsor and trail setting Patients will be recruited at Department of Endocrinology and Internal Medicine from a cohort of more than 1000 well-characterized diabetic patients. The main investigator finished his masters as a biomedical engineer at the MR Centre at Aarhus University Hospital where he specialized in MR scanning techniques and has since been working with research combining diabetes, neuropathy, MR techniques and image processing. The studies will be conducted in collaboration between Siemens AG, Copenhagen, Department of Endocrinology and Internal Medicine, Department of Neurology, MR Centre at Aarhus University Hospital, Department of Endocrinology and Internal Medicine at Odense University Hospital and Department of Neuroradiology at Heidelberg University Hospital.