Can imaging be the new yardstick for diagnosing peripheral neuropathy?—a comparison between high resolution ultrasound and MR neurography with an approach to diagnosis

Abstract

PurposePeripheral neuropathies are a group of disorders which affect the peripheral nervous system which have been conventionally diagnosed using electrodiagnostic studies. This study was carried out to assess the role of imaging in diagnosing peripheral mononeuropathy as exact anatomical localisation of the pathology is possible using high-resolution ultrasound and MR neurography, the modalities assessed in this study.MethodA hospital-based prospective analytical study was carried out in a resource-limited setting on 180 peripheral nerves in 131 patients with symptoms of peripheral mononeuropathy after taking IRB approval. Each patient underwent high-resolution ultrasound examination and MR neurography, findings of which were then compared and statistically analysed assuming electrodiagnostic findings as the gold standard.ResultsOverall, the diagnostic accuracy was highest for the proton density fat-saturated MR sequence (93.89%) followed by high-resolution ultrasound (80%). The sensitivity was highest for proton density fat-saturated sequence while the T1 MR sequence had the highest specificity. Combined diagnostic accuracy of both modalities was calculated to be 93.33% with a negative predictive value of 80%. High-resolution ultrasound and MRI equally detected the cases with nerve discontinuity, while neuromas were better identified on MRI.ConclusionWith the advent of higher frequency probes and improved MR field strength, imaging of peripheral nerves is possible with better accuracy. Imaging assessment of nerves allows anatomical delineation with identification of exact site of involvement. This comparative study demonstrates the role of imaging in diagnosing peripheral nerve pathologies with the accuracy of MRI as high as 93.89% which may serve as an imaging gold standard. High-resolution ultrasound, being quicker, cost effective and a comparable accuracy of 80% can serve as a reliable screening tool. This study incorporates a larger study group and compares HRUS with MRI, taking NCV as gold standard, which has not been done in the preceding studies. With this study, we conclude that these two imaging modalities are not mutually exclusive. Rather, they complement each other and can be used in conjunction as an imaging yardstick for diagnosing peripheral neuropathies.Electronic supplementary materialThe online version of this article (10.1186/s13244-019-0787-6) contains supplementary material, which is available to authorized users.

Performance Evaluation of High-Resolution Ultrasound versus Magnetic Resonance Imaging in Diagnosing Peripheral Nerve Pathologies

“…Our study has shown MRN to be more accurate in detecting the peripheral nerve pathologies (89.3 vs. 82.9%) with higher negative predictive values for diagnosing the lesions. Similar findings were noted in a comparative study published by Agarwal et al, 8 who also reported higher accuracy of MRI over HRUS (93.89 vs. 86.11%) with higher negative predictive value of MRI. The confidence levels to detect pathological characters like caliber change ( p = 0.007) and nerve discontinuity ( p = 0.009) were higher with HRUS than MRI (100 vs. 50% and 100 vs. 70%, respectively) and found to be statistically significant ( p <0.05).…”

“…Agarwal et al 8 also reported higher specificity with MRI (86.67 vs. 80%) with higher positive predictive values; however, in our study HRUS showed higher positive predictive value (100 vs. 95%) with higher specificity (100 vs. 66.6%), which can be attributed to poor image quality for MRN in few of our patients with metallic implants or movement artifacts and use of high-resolution sonographic probe. Zaidman et al 11 found specificity to be similar with both modalities, while Garg et al 9 have not evaluated both for the same.…”

Readout-segmented diffusion tensor imaging for assessing sciatic nerve invasion by soft tissue tumor

“…[14][15][16] In recent years, several MR sequences have been tried for peripheral nerve diseases. [17][18][19] However, they fail to provide objective parameters to re ect intrinsic characteristics of nerve. Readout-segmented DTI was thus introduced by us as a new way to assess peripheral nerve, as it could provide quantitative parameters including FA and ADC.…”

Magnetic Resonance Neurography for Evaluation of Peripheral Nerves

“…16 Deviations from the norm may be interpreted as signs of an underlying condition. [17][18][19] For example, findings of chronic nerve entrapment on MRN include nerve swelling proximally and sometimes distally with an abrupt transition to a flattened contour at the entrapment site. 20 Aggarwal et al described a case of an 18-year-old man presenting with a medial epicondyle fracture and elbow dislocation treated via closed reduction of the elbow and cast immobilization.…”