Relation between electrophysiological findings and diffusion weighted magnetic resonance imaging in ulnar neuropathy at the elbow

Reliability and validity of the modified McGowan grade in patients with cubital tunnel syndrome

INTRODUCTION

This study aimed to assess the reliability and validity of the modified McGowan grading system and to determine its ability to distinguish the severity of cubital tunnel syndrome (CuTS) between the different grades.

MATERIALS AND METHODS

We prospectively enrolled 39 consecutive patients with CuTS from March 2018 to December 2020. Inter- and intra-observer reliability was assessed by two orthopaedic surgeons with a minimum 2-week interval using Cohen kappa coefficients. Validity was assessed by Spearman's correlation with objective clinical outcomes (grip strength, Semmes-Weinstein monofilament test [SWMT], static two-point discrimination [2PD], and motor conduction velocity [MCV]). In addition, the relationship between the grading system and patient-reported outcomes (Disabilities of the Arm, Shoulder and Hand score and Boston Questionnaire) was evaluated using Spearman's correlation. The ability to distinguish the severity between the different grades was assessed using the Kruskal-Wallis analysis.

RESULTS

The inter-observer kappa value was 0.54 and intra-observer kappa value was 0.59, which imply a moderate reliability. The modified McGowan grade had a moderate correlation with objective clinical outcomes (grip strength [r = - 0.350, p = 0.029], SWMT [r = 0.552, p < 0.001], 2PD [r = 0.456, p = 0.004], and MCV [r = - 0.394, p = 0.021]). However, patient-reported outcomes did not correlate with this grading system. Kruskal-Wallis analysis revealed significant differences between grades in terms of SWMT, 2PD, grip strength, and Boston Questionnaire functional score (p = 0.006, 0.025, 0.014, and 0.043, respectively); however, these differences were statistically significant only for a limited number of parts.

CONCLUSIONS

The modified McGowan grade has a moderate inter- and intra-observer reliability. This grading system moderately correlates with objective sensory-motor functions and MCV of patients with CuTS. However, the modified McGowan grade does not reflect the patient's perceived disabilities and has a weakness in distinguishing the severity of patients' conditions among the different grades.

Comparison of electrodiagnosis, neurosonography and MR neurography in localization of ulnar neuropathy at the elbow

INTRODUCTION

In patients with ulnar neuropathy at the elbow (UNE) the precise determination of the site of lesion is important for subsequent differential diagnostic considerations and therapeutic management. Due to a paucity of comparable data, to better define the role of different diagnostic tests, we performed the first prospective study comparing the diagnostic accuracy of short segment nerve stimulation, nerve ultrasonography, MR neurography (MRN), and diffusion tensor imaging (DTI) in patients with UNE.

METHODS

UNE was clinically diagnosed in 17 patients with 18 affected elbows. For all 18 affected elbows in patients and 20 elbows in 10 healthy volunteers, measurements of all different diagnostic tests were performed at six anatomical positions across the elbow with measuring points from distal (D4) to proximal (P6) in relation to the medial epicondyle (P0). Additional qualitative assessment regarding structural changes of surrounding nerve anatomy was conducted.

RESULTS

The difference between affected arms of patients and healthy control arms were most frequently the largest at measure intervals D2 to P0 and P0 to P2 for electrophysiological testing, or measure points P0 and P2 for all other devices, respectively. At both levels P0 and at P2, T2 contrast-to-noise ratio (CNR) of MRN and mean diffusivity (MD) of DTI-based MRN showed best accuracies.

DISCUSSION

This study revealed differences in diagnostic performance of tests concerning a specific location of UNE, with better results for T2 contrast to noise ratio (CNR) in MRN and mean diffusivity of DTI-based MRN. Additional testing with MRN and nerve ultrasonography is recommended to uncover anatomical changes.

Peripheral nerve imaging

Disorders of peripheral nerve have been traditionally diagnosed and monitored using clinical and electrodiagnostic approaches. The last two decades have seen rapid development of both magnetic resonance imaging (MRI) and ultrasound imaging of peripheral nerve, such that these imaging modalities are increasingly invaluable to the diagnosis of patients with peripheral nerve disorders. Peripheral nerve imaging provides information which is supplementary to clinical and electrodiagnostic diagnosis. Both MRI and ultrasound have particular benefits in specific clinical circumstances and can be considered as complementary techniques. These technologic developments in peripheral nerve imaging will usher in an era of multimodality assessment of peripheral nerve disorders, with clinical evaluations supported by anatomic information from imaging, and functional information from electrodiagnostic studies. Such a multimodality approach will improve the accuracy and efficiency of patient care.

Approach to MR Imaging of the Elbow and Wrist: Technical Aspects and Innovation

Wrist and elbow MR imaging technology is advancing at a dramatic rate. Wrist and elbow MR imaging is performed at medium and higher field strengths with more specialized surface coils and more variable pulse sequences and postprocessing techniques. High field imaging and improved coils lead to an increased signal-to-noise ratio and increased variety of soft tissue contrast options. Three-dimensional imaging is improving in terms of usability and artifacts. Some of these advances have challenges in wrist and elbow imaging, such as postoperative patient imaging, cartilage mapping, and molecular imaging. This review considers technical advances in hardware and software and their clinical applications.

Accuracy of MRI in diagnosing peripheral nerve disease: a systematic review of the literature

OBJECTIVE

MRI is increasingly being used to evaluate extracranial peripheral nerve disease in clinical practice. The objective of this study was to systematically review the accuracy of MRI in distinguishing normal from abnormal extracranial peripheral nerves.

CONCLUSION

There is significant heterogeneity between studies investigating the accuracy of MRI. Studies have shown that nerve T2-weighted or STIR hyperintensity, nerve enlargement, and nerve flattening are associated with peripheral nerve disease.