Gerd Bodner

Tumors and Tumor-Like Lesions

Peripheral nerve tumors are uncommon, nerve sheath tumors, schwannoma and neurofibromas being the most frequent. Their clinical signs and symptoms are often unspecific, which is why they may pose a diagnostic problem; this is particularly true for the neck, where a palpable mass is often mistaken for an enlarged lymph node by the referring clinician. Several neurogenic tumors can affect the musculoskeletal system, including traumatic neuroma, Morton’s neuroma, neural fibrolipoma, nerve sheath ganglia, neurilemmoma, neurofibroma and malignant peripheral nerve sheath tumors (Murphey et al. 1999). In general the diagnosis of such a lesion is based on the detection of a mass in association with neurologic signs. It is important, however, to delimitate musculoskeletal lesions with secondary nerve involvement from lesions directly derived from neurogenic tissue. In this regard imaging may be helpful, but only if the applied method has the potential to establish the diagnosis by demonstration of a lesion in direct continuity with a peripheral nerve.

3T MR tomography of the brachial plexus: structural and microstructural evaluation.

Magnetic resonance (MR) neurography comprises an evolving group of techniques with the potential to allow optimal noninvasive evaluation of many abnormalities of the brachial plexus. MR neurography is clinically useful in the evaluation of suspected brachial plexus traumatic injuries, intrinsic and extrinsic tumors, and post-radiogenic inflammation, and can be particularly beneficial in pediatric patients with obstetric trauma to the brachial plexus. The most common MR neurographic techniques for displaying the brachial plexus can be divided into two categories: structural MR neurography; and microstructural MR neurography. Structural MR neurography uses mainly the STIR sequence to image the nerves of the brachial plexus, can be performed in 2D or 3D mode, and the 2D sequence can be repeated in different planes. Microstructural MR neurography depends on the diffusion tensor imaging that provides quantitative information about the degree and direction of water diffusion within the nerves of the brachial plexus, as well as on tractography to visualize the white matter tracts and to characterize their integrity. The successful evaluation of the brachial plexus requires the implementation of appropriate techniques and familiarity with the pathologies that might involve the brachial plexus.

Dual-energy computed tomography compared with ultrasound in the diagnosis of gout

OBJECTIVES The aim of our study was to compare dual-energy CT (DECT) with US for the diagnosis of gouty arthritis and to correlate the imaging findings with results from synovial fluid aspiration whenever possible. METHODS We recruited 21 patients (17 male and 4 female) who presented with a clinical suspicion of acute or chronic gout in 37 joints. DECT scans of the hands, wrists, feet, ankles, knees and elbows were performed. For post-processing, a colour-coding gout software protocol was used. US examinations of the same joints were performed. In addition, joint fluid aspiration was performed in a total of 14 joints. RESULTS DECT images were positive for urate crystal deposits in 25 of 37 joints. US findings were positive in 24 of 37 examined joints. In 12 of 14 joints the synovial fluid aspiration was positive. CT and US findings correlated in 32 of 37 joints (86.5%; κ = 0.698, P < 0.001). CT and synovial fluid results correlated in 12 of 14 joints (85.7%; κ = 0.417, P = 0.119). US and cytology findings correlated in 14 of 14 joints (100%; κ = 1, P < 0.001). CONCLUSION DECT and US have comparable sensitivity for the detection of gouty arthritis in a clinical setting. However, DECT results should be interpreted carefully, as there could be some false-negative findings.

Ultrasound of the lateral femoral cutaneous nerve: normal findings in a cadaver and in volunteers.

Objective: To assess the feasibility of ultrasound (US) in visualizing the lateral femoral cutaneous nerve (LFCN) in a cadaver and 8 volunteers. Methods: Ultrasound and US-guided dye injection was performed in 1 cadaver to show the feasibility of detecting the LFCN. We then performed US in 8 volunteers to assess position of the nerve in respect to the anterior iliac spine. We subsequently performed US-guided anesthetic block of the LFCN on both sides with 0.3 mL local anesthetic. Success rate, time to maximum peak blockade, and duration of blockade were noted. Results: Ultrasound allowed visualization of the LFCN in the cadaveric specimen on both sides and in all but 1 volunteer. Ultrasound-guided block of the LFCN was successful in all but 1 volunteer. The mean distance of LFCN from the anterior iliac spine was 2.9 cm on the right side and 2.8 cm on the left side. The mean duration of the block was 4.4 hours. Conclusion: Ultrasound enables visualization of the LFCN in a cadaver and in volunteers. Ultrasound-guided injection successfully blocked the LFCN.

Peripheral 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. With US guidance, the radiologist can visualize the needle tip continuously and ensure that the needle is placed precisely in the desired location, avoiding the risk of inadvertent nerve damage. Practical tips and tricks for US-guided needle placement, biopsy of neural lesions, and US-guided therapy are reviewed in this article. The use of US-guided injections in specific clinical settings, such as the percutaneous treatment of carpal tunnel syndrome, Mortons 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.

Sonographic Imaging of Abdominal and Extraabdominal Desmoids

PURPOSE To describe the sonographic imaging characteristics of abdominal and extraabdominal desmoids. MATERIALS AND METHODS We retrospectively investigated 12 histologically and pathologically proven abdominal and extraabdominal desmoids. Two radiologists with musculoskeletal sonography experience reviewed sonographic images for lesion location, size, echotexture, and vascularity with agreement by consensus. RESULTS Desmoids were seen in 9 females and 3 males. They manifested as slowly growing masses. Nine lesions were intramuscular and 3 were found within the subcutaneous adipose tissue. A typical sonographic feature of all intramuscular desmoids was the spindle-shaped margin at the tumor ends when scanned along the long axis of the affected muscle. The desmoids arising from the fascia had an irregular shape. Tumor vascularity was rich in 6 cases and poor in 6 cases. A fibrillar pattern within the tumor was found in 75% of the cases. CONCLUSION A spindle-shaped appearance is common in intramuscular desmoids. Hyperechoic areas and a fibrillar pattern within desmoids are also common sonographic features.

Imaging of posterior tibial tendon dysfunction—Comparison of high-resolution ultrasound and 3 T MRI

PURPOSE Posterior tibial tendon dysfunction is the most common cause of acquired asymmetric flatfoot deformity. The purpose of this study was to determine and compare the diagnostic value of MRI and high-resolution ultrasound (HR-US) in posterior tibial tendon dysfunction (PTTD), and assess their correlation with intraoperative findings. MATERIALS AND METHODS We reviewed 23 posterior tibial tendons in 23 patients with clinical findings of PTTD (13 females, 10 males; mean age, 50 years) with 18MHz HR-US and 3T MRI. Surgical intervention was performed in nine patients. RESULTS HR-US findings included 2 complete tears, 6 partial tears, 10 tendons with tendinosis, and 5 unremarkable tendons. MRI demonstrated 2 complete tears, 7 partial tears, 10 tendons with tendinosis, and 4 unremarkable tendons. HR-US and MRI were concordant in 20/23 cases (87%). Image findings for HR-US were confirmed in six of nine patients (66.7%) by intraoperative inspection, whereas imaging findings for MRI were concordant with five of nine cases (55.6%). CONCLUSION Our results indicate that HR-US can be considered slightly more accurate than MRI in the detection of PTTD.

Neuroimaging of classic neuralgic amyotrophy

Introduction: Neuralgic amyotrophy (NA) often imposes diagnostic problems. Recently, MRI and high‐resolution ultrasound (HRUS) have proven useful in diagnosing peripheral nerve disorders. Methods: We performed a chart and imaging review of patients who were examined using neuroimaging and who were referred because of clinically diagnosed NA between March 1, 2014 and May 1, 2015. Results: Six patients were included. All underwent HRUS, and 5 underwent MRI. Time from onset to evaluation ranged from 2 weeks to 6 months. HRUS showed segmental swelling of all clinically affected nerves/trunks. Atrophy of muscles was detected in those assessed >1 month after onset. MRI showed T2‐weighted hyperintensity in all clinically affected nerves, except for the long thoracic nerve, and denervation edema of muscles. Conclusions: HRUS and MRI are valuable diagnostic tools in NA. This could change the diagnostic approach from one now focused on excluding other disorders to confirming NA through imaging markers. Muscle Nerve 54: 1079–1085, 2016

Visualization of the Long Thoracic Nerve using High-Resolution Sonography.

PURPOSE The long thoracic nerve (LTN) innervates the serratus anterior muscle (SA) which plays an important role in shoulder function. Evaluation of the LTN has so far been restricted to clinical assessment and partly electromyography and neurography. Progress of high-resolution ultrasound (HRUS) increasingly enables visualization of small peripheral nerves and their pathologies. We therefore aimed at (a) clarifying the possibility of visualization of the LTN from its origin to the most distal point in the supraclavicular region visible and (b) developing an ultrasound protocol for routine use. We further present two cases of patients with LTN pathology. METHODS The study consisted of two parts: Part 1 included 4 non-enbalmed human bodies in whom the LTN (n = 8) was located and then marked by ink injection. Correct identification was confirmed by anatomical dissection. Part 2 included 20 healthy volunteers whose LTN (n = 40) was assessed independently by two radiologists. Identification of the LTN was defined as consensus in recorded images. RESULTS LTN was clearly visible in all anatomical specimens and volunteers using HRUS and could be followed until the second slip of the serratus anterior muscle from the supraclavicular region. In anatomical specimens, dissection confirmed HRUS findings. For all volunteers, consensus was obtained. The mean nerve diameter was 1.6 mm ± 0.3 (range 1.1 - 2.1 mm) after the formation of the main trunk. DISCUSSION We hereby confirm a reliable possibility of visualization of the LTN in anatomical specimens as well as in volunteers. We encourage HRUS of the LTN to be part of the diagnostic work-up in patients presenting with scapular winging, shoulder weakness or pain of unknown origin.

High-Resolution Ultrasound for Diagnostic Assessment of the Great Auricular Nerve--Normal and First Pathologic Findings.

PURPOSE The great auricular nerve (GAN) is a sensory branch of the superficial cervical plexus. While its blockade is an established procedure, little is known about the ultrasound appearance of pathologic conditions of the GAN itself. We, therefore, aimed to evaluate the possibility of the visualization and diagnostic assessment of the GAN along its entire course by means of high-resolution ultrasound (HRUS). MATERIALS AND METHODS To assess the feasibility of visualization, we performed HRUS with an 18 MHz probe, HRUS-guided, fine-needle ink markings and consecutive dissection in six anatomical specimens. Then, we measured the diameter of the GAN in healthy volunteers and finally performed a retrospective review of patients referred for HRUS examinations because of pain within GAN territory between August 1, 2012 and August 1, 2013. RESULTS The GAN was clearly visible with HRUS from its formation to the final branches, and was marked successfully on both sides in all anatomical specimens (n = 12). The mean average in-vivo was 0.14 cm ± 0.03 (range 0.08-0.2). Seven cases of patients with GAN pathologies of various origins (idiopathic, traumatic, tumorous and iatrogenic) were identified, of which 6 were visible on HRUS and all of which could be confirmed by complete resolution of symptoms after selective HRUS-guided GAN block. CONCLUSION This study confirms the reliable ability to visualize the GAN with HRUS throughout its course, both in anatomical specimens and in vivo. The provided cases show that pathologies of the GAN seem to have a variety of causes and may not be rare. We, therefore, encourage the use of HRUS in patients with unclear pain in the auricular, periauricular and posterior-lateral head.