Seminars in musculoskeletal radiology
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The diagnosis of a peripheral nerve tumor can often be suggested on imaging. Direct continuity with a neural structure or location along a typical nerve distribution, shape, and intrinsic magnetic resonance (MR) signal characteristics represent the most important signs in this regard. ⋯ This article reviews the MR imaging appearance, clinical and pathological features of schwannoma, localized neurofibroma, plexiform neurofibroma, intraneural perineurioma, fibrolipomatous hamartoma, nerve sheath ganglion, traumatic neuroma, malignant peripheral nerve sheath tumor, and secondary malignant neoplasms of peripheral nerves. Typical findings are illustrated on the basis of histologically confirmed cases.
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Clinicians frequently encounter compressive neuropathies of the lower extremity. The clinical history and physical examination, along with electrodiagnostic testing and imaging studies, lead to the correct diagnosis. ⋯ We provide a detailed review of compression neuropathies of the lower extremity with an emphasis on magnetic resonance (MR) imaging characteristics. We discuss the clinical presentation, etiology, anatomical location, and MR imaging appearance of these neuropathies, including the piriformis syndrome, iliacus syndrome, saphenous neuropathy, obturator neuropathy, lateral femoral cutaneous neuropathy (meralgia paresthetica), proximal tibial neuropathy, common peroneal neuropathy, deep peroneal neuropathy, superficial peroneal neuropathy, tarsal tunnel syndrome, Baxter's neuropathy, jogger's foot, sural neuropathy, and Morton's neuroma.
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Semin Musculoskelet Radiol · Nov 2010
ReviewPeripheral nerves: ultrasound-guided interventional procedures.
Specific ultrasound (US)-guided interventional procedures on peripheral nerves are reviewed in this article including regional anesthesia, biopsy of neural lesions, and some injection therapies. For these procedures, US is the best modality to provide a safe imaging guidance because of its excellent spatial resolution and real-time capabilities. ⋯ The use of US-guided injections in specific clinical settings, such as the percutaneous treatment of carpal tunnel syndrome, Morton's and saphenous neuromas, painful stump neuromas, piriformis syndrome, and meralgia paresthetica are also illustrated here. US allows the clinician to inject drugs with little or no patient discomfort.
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Ultrasound (US) and MR imaging have been shown able to detect in-depth features of brachial plexus anatomy and to localize pathological lesions in disorders where electrophysiology and physical findings are nonspecific or nonlocalizing. High-end gradient technology, phased array coils, and selection of an appropriate protocol of pulse sequences are the main requirements to evaluate the brachial plexus nerves with MR imaging and to distinguish between intrinsic and extrinsic pathological changes. A careful scanning technique based on anatomical landmarks is required to image the brachial plexus nerves with US. ⋯ In the thoracic outlet syndrome, imaging performed in association with postural maneuvers can help diagnose dynamic compressions. MR imaging and US are also effective to recognize neuropathies about the shoulder girdle involving the suprascapular, axillary, long thoracic, and spinal accessory nerves that may mimic brachial plexopathy. In this article, the clinical entities just listed are discussed independently, providing an overview of the current status of knowledge regarding imaging assessment.
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Semin Musculoskelet Radiol · Nov 2010
ReviewEntrapment neuropathies I: upper limb (carpal tunnel excluded).
Several entrapment neuropathies of the upper extremity can cause hypoechoic swelling and nerve compression as seen at ultrasound. The ulnar nerve can be compressed at the cubital tunnel of the elbow and Guyon's canal at the wrist. ⋯ In addition to compression at the carpal tunnel, the median nerve may be compressed at the elbow, related to a supracondylar process or by the pronator teres. Knowledge of these key anatomical sites of potential nerve compression is essential for accurate diagnosis of entrapment neuropathies.