0011: Intraneural Ganglia

Abstracts and intraneural ganglia, developing within the nerve. At the lateral calf, the superficial peroneal neuropathy can be encountered in patients who have a history of ankle sprains or trauma to the leg leading to sensory disturbances on the dorsal ankle and foot. US can demonstrate the nerve injury as a fusiform hypoechoic thickening of the superficial peroneal nerve at the point where the nerve pierces the fascia. The tarsal tunnel syndrome refers to the entrapment of the tibial nerve and/or of its divisional branches at the medial ankle. US can provide exact information on the nature and extent of constricting findings. Repetitive minor contusion traumas can cause impingement of the deep peroneal nerve that occurs on the dorsal aspect of the midfoot leading to local burning pain. Similarly, the interdigital nerves can be impinged against the distal edge of the intermetatarsal ligament forming a Morton neuroma.Ultrasound (US) can give direct demonstration of a wide range of neuropathies of the lower extremity. In the hip, the entrapment of the sciatic, femoral and lateral femorocutaneous nerves can be depicted with US. Main signs of nerve compression include echotextural abnormalities, displacement of the affected nerve from its normal course by space-occupying masses and selective changes in the innervated muscles related to denervation edema and fatty infiltration. At the lateral knee, the entrapment of the common peroneal nerve typically occurs between the bone and the fascia as the nerve winds around the fibular neck. In most cases, nerve traumas result from external pressure at the fibular neck. Ganglion cysts are one of the leading causes of peroneal nerve compression at this site: these cysts may be divided in extraneural ganglia, which develop outside the nerve and compress it later and intraneural ganglia, developing within the nerve. At the lateral calf, the superficial peroneal neuropathy can be encountered in patients who have a history of ankle sprains or trauma to the leg leading to sensory disturbances on the dorsal ankle and foot. US can demonstrate the nerve injury as a fusiform hypoechoic thickening of the superficial peroneal nerve at the point where the nerve pierces the fascia. The tarsal tunnel syndrome refers to the entrapment of the tibial nerve and/or of its divisional branches at the medial ankle. US can provide exact information on the nature and extent of constricting findings. Repetitive minor contusion traumas can cause impingement of the deep peroneal nerve that occurs on the dorsal aspect of the midfoot leading to local burning pain. Similarly, the interdigital nerves can be impinged against the distal edge of the intermetatarsal ligament forming a Morton neuroma. 0010 Upper Limb Nerve Entrapment Syndromes Sean McPeake, Benson Radiology, Australia As an imaging modality, ultrasound has enjoyed fantastic advances in the past 15 years meaning that many of the large peripheral nerves (and even their smaller branches) can be reviewed in fantastic detail. We will follow the peripheral nerves of the upper limb down from the brachial plexus and consider the common points of nerve entrapment, the effect this entrapment has on the limb and what role ultrasound has to play in the workup of these conditions. A constant theme of the presentation will be to answer the question; when should I look for that? Understanding nerve entrapment syndromes is important! Carpal Tunnel Syndrome and Cubital Tunnel Syndrome are common clinical entities and as such all musculoskeletal sonologists and sonographers should have a sound knowledge of these conditions and their ultrasound appearance. In addition to these common conditions we will review the less common nerves entrapment syndromes of the upper limb such as Radial and Ulnar Tunnel Syndromes.

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References Duncan I, Sullivan P, Lomas F. Sonography in the diagnosis of Carpal Tunnel Syndrome. AJR 1999; 173:681-684. Gassner E et al. Persistent Median Artery in the Carpal Tunnel. Colour Doppler Ultrasonographic Findings. J Ultrasound Med 21:455-461, 2002. Tayfun Altinok M et al. Sonographic Evaluation of the Carpal Tunnel after Provocative Exercises. J Ultrasound Med 2004; 23: 1301-1306. Beekman R, Visser LH. Sonography in the Diagnosis of Carpal Tunnel Syndrome: A critical review of the Literature. Muscle Nerve 2003; 27: 26-33. Bodner G et al. Ultrasonographic Appearance of Supinator Syndrome. J Ultrasound Med 21: 1289-1293. Beltran J, Rosenberg Z. Nerve Entrapment. Musculoskeletal Radiology. 1998; 2:175-84. Cross-Sectional Imaging of Peripheral Nerve Sheath Tumors:Characteristic Signs on CT, MR Imaging, and Sonography. John Lin. AJR: 176, January 2001. Sonography and MR Imaging of Posterior Interosseous Nerve Syndrome with Surgical Correlation. Alexander J. Chien et al AJR:181, July 2003. Sonographic Evaluation of the Median Nerve at the Wrist. David A. Jamadar. J Ultrasound Med 20:1011-1014, 2001. 0011 Intraneural Ganglia Neil Simmons, Dr Jones & Partners, Australia Intraneural ganglia are rarely reported conditions affecting peripheral nerves. Lack of knowledge of these lesions is probably the reason for the few reports. The author has scanned at least five such lesions, but was only able to report one [the most recent] correctly due to ignorance of the condition. It is hoped that increased awareness will result in more of these lesions being reported as they are easily treated surgically. The literature has been reviewed. The theories on how these ganglia form, their patterns of spread and nerves most commonly affected will be discussed. The importance of identifying articular nerve connections will be emphasised. 0012 Imaging Before Carotid Intervention, What’s Enough? Philip Walker, University of Queensland, Department of Vascular Surgery, RBWH, Australia The options for carotid intervention have expanded from the situation where carotid endarterectomy (CEA) was the sole option for the treatment of carotid bifurcation disease, to the situation where carotid artery stenting (CAS) is an alternative for selected patients. There has also been an evolution in the availability and application of the various imaging modalities employed before embarking on carotid intervention. Initially angiography was the only available option. When carotid duplex ultrasound (CDUS) emerged it was initially employed as a screening test, but over time became the sole preoperative imaging modality prior to carotid endarterectomy for many patients, with complementary angiography reserved for selected patients. CT angiography (CTA) and MRA / MRI have emerged as non-invasive alternatives to catheter angiography (albeit with their own set of limitations) and allow interrogation of the carotid vessels from the arch to the intracranial circulation, together with the ability to combine with cerebral imaging. Because of the limited efficacy of carotid intervention for asymptomatic carotid stenosis interest has turned to attempting to identify the “vulnerable carotid plaque” in an effort to better select that small group of patients who might benefit from intervention. The advent of CAS mandates imaging of the arch and proximal carotid vessels to assess