Clarissa Canella

Peripheral tumor and tumor-like neurogenic lesions

Neoplasms of neurogenic origin account for about 12% of all benign and 8% of all malignant soft tissue neoplasms. Traumatic neuroma, Morton neuroma, lipomatosis of a nerve, nerve sheath ganglion, perineurioma, benign and malignant peripheral nerve sheath tumors (PNST) are included in this group of pathologies. Clinical and radiologic evaluation of patients with neurogenic tumors and pseudotumors often reveals distinctive features. In this context, advanced imaging techniques, especially ultrasound (US) and magnetic resonance (MR) play an important role in the characterization of these lesions. Imaging findings such as location of a soft tissue mass in the region of a major nerve, nerve entering or exiting the mass, fusiform shape, abnormalities of the muscle supplied by the nerve, split-fat sign, target sign and fascicular appearance should always evoke a peripheric nerve sheath neoplasm. Although no single imaging finding or combination of findings allows definitive differentiation between benign from malign peripheric neurogenic tumors, both US and MR imaging may show useful features that can lead us to a correct diagnosis and improve patient treatment. Traumatic neuromas and Morton neuromas are commonly associated to an amputation stump or are located in the intermetatarsal space. Lipomatosis of a nerve usually appears as a nerve enlargement, with thickened nerve fascicles, embedded in evenly distributed fat. Nerve sheath ganglion has a cystic appearance and commonly occurs at the level of the knee. Intraneural perineuroma usually affects young people and manifests as a focal and fusiform nerve enlargement. In this article, we review clinical characteristics and radiologic appearances of these neurogenic lesions, observing pathologic correlation, when possible.

Use of Tomosynthesis for Erosion Evaluation in Rheumatoid Arthritic Hands and Wrists

PURPOSE To compare tomosynthesis with radiography for the detection of hand and wrist bone erosions in patients with rheumatoid arthritis (RA), using multidetector computed tomography (CT) as the reference method. MATERIALS AND METHODS The study was approved by the local ethics committee, and written consent was obtained from all patients. From December 2008 to April 2009, 30 consecutive patients with RA were included in this prospective study. They underwent radiography, tomosynthesis, and CT of the most symptomatic hand and wrist on the same day. Two radiologists and one rheumatologist independently read images from the three imaging modalities. RESULTS A total of 232 erosions were detected with CT, while 199 and 140 erosions, respectively, were detected with tomosynthesis and radiography. More erosions were revealed with CT than with tomosynthesis and radiography (P < .0001); significantly more erosions were shown with tomosynthesis than with radiography (P < .0001). With CT as the reference method for bone erosions, the overall sensitivity, specificity, and accuracy of tomosynthesis were, respectively, 77.6%, 89.9%, and 83.1%. The corresponding values for radiography were 53.9%, 92%, and 70.9%. The sensitivity of each reader increased by roughly 20% with use of tomosynthesis. CONCLUSION The depiction of bone erosions of the hands and wrists is significantly greater with tomosynthesis than with radiography.

Anatomic Study of the Superficial Peroneal Nerve Using Sonography

OBJECTIVE The purpose of our study was to show that sonography allows precise assessment of the location and course of the superficial peroneal nerve and of its relationship with other structures. MATERIALS AND METHODS This study, initially undertaken in cadavers, was followed by sonographic studies of 30 healthy adult volunteers (60 legs) by two radiologists in consensus. The location and course of the superficial peroneal nerve and its relationship with the adjacent anatomic structures were analyzed. RESULTS The entire course of the superficial peroneal nerve could be identified using sonography. The level at which the superficial peroneal nerve emerges between the peroneus longus and extensor digitorum longus muscles and the level at which it pierces the crural fascia and becomes subcutaneous were found to be highly variable. The superficial peroneal nerve was found to be located in the anterior compartment in 26.7% of the legs and to divide before piercing the crural fascia in 6.7% of the legs. CONCLUSION The superficial peroneal nerve can be clearly depicted by sonography. Knowledge of the nerves precise location, which may show individual variations, may have useful clinical applications.

Lisfranc Joint Ligamentous Complex: MRI With Anatomic Correlation in Cadavers

OBJECTIVE The aim of our study was to clarify the ligamentous anatomy of the Lisfranc joint complex and show the diagnostic capability of MRI in the assessment of the Lisfranc joint complex with detailed anatomic correlation in cadavers. MATERIALS AND METHODS Ten fresh cadaveric feet were studied with high-spatial-resolution MRI before and after the intraarticular injection of a gadopentetate dimeglumine solution. MR images were evaluated by two readers in consensus, with emphasis on the visibility of the ligamentous structures and their appearance. Readers also measured the dimensions (length, width, and thickness) of the Lisfranc ligament and of the first plantar tarsometatarsal ligament, or plantar Lisfranc ligament. For anatomic analysis, nine cadaveric specimens were sectioned in 3-mm-thick slices in the same planes used during MRI. One additional foot specimen was used for dissection. RESULTS In all 10 cadaveric specimens we were able to identify and characterize with MRI the different ligamentous elements that contribute to the overall stability of the Lisfranc joint complex. CONCLUSION By clearly defining the normal ligaments that contribute to the stability of the Lisfranc joint, MRI allows a more precise and correct diagnosis of the origin of the Lisfranc joint instability, perhaps permitting a more specific surgical management. MRI also allows a better understanding of the normal imaging anatomy of the different ligamentous components of the Lisfranc joint, mainly of the Lisfranc and plantar Lisfranc ligaments.

Advanced magnetic resonance imaging techniques in the evaluation of musculoskeletal tumors.

Magnetic resonance (MR) imaging is an important modality for the preoperative and posttreatment evaluation of musculoskeletal tumors. In some cases, MR imaging is unable to offer information about the extension of tumoral necrosis and the presence of viable cells. Advanced MR imaging techniques are now used in association with conventional MR imaging to improve the diagnostic accuracy and the evaluation of treatment response. This article discusses each advanced MR imaging technique with regard to the clinical applications of tumor detection and characterization, differentiation of benign from malignant tumors and tumor tissue from nontumor tissue, and assessment of treatment response.

Ligaments of the Transverse Tarsal Joint Complex: MRI–Anatomic Correlation in Cadavers

OBJECTIVE The objective of our study was to clarify the detailed anatomy of the transverse tarsal joint ligamentous complex and evaluate the diagnostic capability of MRI in the assessment of the tarsal joint complex with detailed anatomic correlation in cadavers. MATERIALS AND METHODS Ten fresh cadaveric feet were studied with high-spatial-resolution MRI before and after intraarticular injection of a gadopentetate dimeglumine solution. MR images were evaluated by two readers, with an emphasis on the visibility of ligamentous structures and their appearance and signal intensity. Readers also measured the dimensions (length, width, and thickness) of the different components of the spring ligament complex, bifurcate ligament, and plantar calcaneocuboid ligaments. For anatomic analysis, nine cadaveric specimens were sectioned in 3-mm-thick slices in the same planes used for MRI. One additional foot specimen was used for dissection. RESULTS In all 10 cadaveric specimens, we were able to identify the various ligamentous elements, their different configurations, imaging characteristics, and contributions to the overall stability of the transverse tarsal joint complex. CONCLUSION By clearly defining the normal ligaments that contribute to the stability of the calcaneocuboid joint, MRI allows a more precise and correct diagnosis of the etiology of the calcaneocuboid instability, perhaps permitting a more specific surgical management. MRI also allows a better understanding of the normal imaging anatomy of the different components of the ligamentous structures of the talocalcaneonavicular joint, particularly of the spring ligament complex.

Anatomical study of phrenic nerve using ultrasound

PurposeTo demonstrate whether ultrasonography may allow a precise assessment of the course and relations of the phrenic nerve in its cervical portion.MethodsThis study, initially undertaken in five cadavers, was followed by high-resolution ultrasonographic study in 20 volunteers (40 nerves) by two radiologists in consensus. The location, course and relations of the phrenic nerve to the adjacent anatomical structures were analysed.ResultsThe phrenic nerve could be nicely identified through the majority of its course by high-resolution ultrasonography. Useful anatomic landmarks for the detection of the nerve could be defined; these include the transverse cervical and ascending cervical arteries. Some anatomical variations were observed.ConclusionKnowledge of the nerve’s precise location, which may demonstrate individual variations, may have useful clinical applications.

MRI in seronegative spondyloarthritis: imaging features and differential diagnosis in the spine and sacroiliac joints.

OBJECTIVE Radiologists should be familiar with MRI findings suggestive of spondyloarthritis and its differential diagnosis. Because most publications describing these features are found in the rheumatologic literature, the purpose of this review is to present these imaging findings of axial spondyloarthritis to radiologists. CONCLUSION New imaging outcomes have improved the diagnosis and follow-up of spondyloarthritis and the assessment of therapeutic modalities. Diagnostic criteria include MRI of the sacroiliac joint, which facilitates earlier diagnosis.

Retinacular disorders of the ankle and foot.

The retinacula of the ankle are distinct structures defined as regions of localized thickening of the crural fascia covering the deep structures of the distal portion of the leg, ankle, and foot. Their role is to maintain the approximation of the tendons to the underlying bone. The retinacula of the ankle and foot contain the extensor retinaculum, the peroneal retinaculum, and the flexor retinaculum. Knowledge of the normal anatomy and imaging appearance of these structures is essential for the depiction of their injuries. Even though they may provide an explanation for chronic and unexplained residual pain after an injury, they are frequently overlooked or misdiagnosed.

Anatomical study of spinal accessory nerve using ultrasonography.

OBJECTIVE The purpose of our study was to demonstrate that ultrasonography may allow a precise assessment of the course and relationships of the spinal accessory nerve (SAN). MATERIAL AND METHODS This study, initially undertaken in 7 cadavers, was followed by high-resolution ultrasonographic study in 15 volunteers (30 nerves) by two radiologists in consensus. The location, course and relations to the adjacent anatomic structures of the SAN were analyzed. RESULTS The precise course of the SAN between the lateroposterior border of the sternocleidomastoid muscle and the anterior border of the trapezius muscle could be identified by high-resolution ultrasonography. In contrast, clinical bone landmarks were not found helpful for the identification of the nerve. CONCLUSION The SAN can be clearly depicted by means of ultrasonography. Knowledge of the nerves precise location, which may evidence individual variations, may have useful clinical applications.