Abstract Details

Title A New Ultrasonographic Parameter to Enhance Diagnostic Yield of Ultrasonography in Patients with Ulnar Mononeuropathy at the Elbow

Topic Neuromuscular and Clinical Neurophysiology (EMG)

Presentation(s) S18 - Neuromuscular and Clinical Neurophysiology (EMG): Neuroimaging, Outcome Measures, and Biomarkers (2:36 PM-2:48 PM)

Poster/Presentation
Number 009

Objective

To determine a new ultrasonographic parameter, including cut-off values for ratio of maximum cross sectional area (CSA) at elbow in symptomatic arm to asymptomatic one (M-ratio) and comparing ratio values of CSA at elbow to: wrist (E/W), mid-forearm (E/F), and mid humerus (E/H) between affected and unaffected arms to improve the sensitivity and specificity of neuromuscular ultrasonography (NM US) in diagnosis of ulnar neuropathy at elbow (UNE).

Background UNE is the second most common entrapment neuropathy. UNE is classically diagnosed using electrodiagnosis which has shown sensitivities ranging from 37% to 86% and specificities of 95% or greater. Several studies have shown ultrasonography can be a valuable diagnostic modality for UNE, especially in entrapment neuropathies

Design/Methods A retrospective case-control analysis of unilateral ulnar mononeuropathy cases (based on the ultrasound and electrodiagnosis) was performed to identify inter- and intra-nerve ratio values between affected and unaffected arms. To identify the best cut-off point for ratios between symptomatic and asymptomatic sides that would distinguish between cases and controls, receiver operating characteristic (ROC) curve analysis was performed

Results

Forty two cases and 45 controls were enrolled. Controls were significantly more likely to be female, and had lower mean weight compared to cases, however there were no significant differences in age, height or BMI. In ROC analysis, the area under of the curve for M ratio was 0.984 and the best cut-off point was 1.22 [Sensitivity: 92.9%, Specificity: 97.8%, positive predictive value (PPV): 97.5%, negative predictive value (NPV): 93.6%]. Optimal cut-off point for E/W, E/F and E/H ratios were 1.07 (Sensitivity: 98%, Specificity: 78%, PPV: 80%, NPV: 94.7%), 1.11 (Sensitivity: 95%, Specificity: 80%, PPV: 81.6%, NPV: 94.7%) and 1.18 (Sensitivity: 95%, Specificity: 93%, PPV: 93%, NPV: 95%), respectively.

Conclusions The M-ratio exhibits a high diagnostic accuracy in the ultrasonographic diagnosis of UNE, surpassing more conventionally used NM US parameters.

Authors/Disclosures
Mansoureh Mamarabadi, MD PRESENTER	Dr. Mamarabadi has nothing to disclose.
John A. Morren, MD, FAAN (Cleveland Clinic)	Dr. Morren has received publishing royalties from a publication relating to health care.
Steven Shook, MD (Cleveland Clinic)	Dr. Shook has nothing to disclose.

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