Morphological correlates of oxaliplatin induced peripheral neuropathy assessed by magnetic resonance neurography.

Abstract

10092 Background: Oxaliplatin induced peripheral neuropathy (OXA-PNP) is a frequent side effect of oxaliplatin containing chemotherapy protocols. It is commonly assessed clinically via physical examination and patient reported symptoms. Research has been impeded by the lack of objective tests to quantify OXA-PNP. Neurophysiological examination is time-consuming and can only cover a selected part of the examined nerve. The aim of this study was to investigate in-vivo morphological correlates of OXA-PNP by magnetic resonance neurography (MRN). Methods: 20 patients with mild to moderate OXA-PNP and 20 matched controls were prospectively enrolled. All patients underwent a detailed neurophysiology examination prior to neuroimaging. A standardized MRN imaging protocol at 3.0 Tesla with large-coverage included the lumbosacral plexus, as well as both sciatic nerves and their branches using T2-weighted fat-saturated sequences at high resolution. Qualitative evaluation of sciatic, tibial, and peroneal nerves were performed by two readers regarding the presence, degree, and distribution of nerve lesions. Quantitative assessment included volumetry of the dorsal root ganglia (DRG) and sciatic nerve normalized T2 (nT2) signal and caliber. Results: Significant DRG hypertrophy in OXA-PNP patients (207.3±47.7mm3 vs. 153.0±47.1mm3 in controls, p = 0.001) was found as morphological correlate of the sensory neuronopathy. Peripheral nerves only exhibited slight morphological alterations qualitatively. Quantitatively, sciatic nerve caliber was unchanged (26.0±5.1mm2 vs. 27.4±7.4mm2, p = 0.19) while sciatic nerve nT2 signal was slightly and non-significantly elevated in patients (1.32±0.22 vs. 1.22±0.26, p = 0.19). Conclusions: OXA-PNP leads to morphological correlates that can be detected in-vivo by MRN. Significant hypertrophy of the DRG was observed, a phenomenon which has not been described in OXA-PNP previously. DRG volume should be investigated as a biomarker in other sensory peripheral neuropathies and ganglionopathies as well as in studies evaluating neuroprotective strategies for OXA-PNP.