Case Illustrates the Value of Ultrasound Neurography

By Joshua Polster, MD

A 34-year-old woman with no significant medical history presented with a chief complaint of left groin pain that came on suddenly one year earlier during a 15-mile marathon-training run. She reported that the pain was aggravated by most activities. She also had intermittent left lateral thigh numbness.

She had a prior workup at an outside institution that included lumbar spine MRI, diagnostic laparoscopy to evaluate for ovarian pathology, colonoscopy and cystoscopy, all of which were negative. Physical exam demonstrated localized tenderness about 2 cm medial and inferior to the left anteriorsuperior iliac spine. Strength was normal.

Cleveland Clinic sports health orthopaedic surgeon James Rosneck, MD, referred the patient for dedicated ultrasound neurography, which demonstrated asymmetric thickening of the left femoral cutaneous nerve just distal to the left anterior-superior iliac spine, where there was associated tenderness. Figure 1 contrasts a longitudinal view of the abnormally thickened lateral femoral cutaneous nerve (left image) with a longitudinal view of the contralateral normal nerve (right image). Figure 2 demonstrates the same side-to-side difference in the transverse plane.

Figure 1. Longitudinal views on ultrasound neurography showing an abnormally thickened lateral femoral cutaneous nerve (arrow, left image) in contrast with the contralateral normal nerve (arrow, right image).
Figure 2. Transverse views on ultrasound neurography demonstrating the same side-to-side difference as in Figure 1.

Based on these imaging findings and the clinical history, the patient was diagnosed with lateral femoral cutaneous neuropathy. She was relieved to have the likely cause of her symptoms found after numerous other normal studies.

Ultrasound neurography: Plenty of advantages, but expertise required

Ultrasound neurography is the specialized use of ultrasound imaging to evaluate peripheral nerves. This technique offers several potential advantages relative to MR neurography, including:

• High-spatial-resolution imaging focused over the area of interest
• Ability to follow the nerve course throughout its length
• Correlation with location of symptoms
• Ability to perform dynamic studies
• Lower cost

Ultrasound neurography requires high-frequency ultrasound probes and detailed knowledge of peripheral nerve anatomy. For these reasons, ultrasound neurography is performed at Cleveland Clinic by subspecialty-trained musculoskeletal radiologists and neurologists.

Dr. Polster is a musculoskeletal radiologist in the Department of Diagnostic Radiology.