Deep branch of the radial nerve: effect of pronation/supination on longitudinal nerve alignment.

OBJECTIVE: To evaluate the effect of maximal pronation and supination of the forearm on the alignment and anatomic relationship of the deep branch of the radial nerve (DBRN) at the superior arcade of the supinator muscle (SASM) by using high-resolution ultrasound (HRUS). MATERIALS AND METHODS: In this cross-sectional study, HRUS in the long axis of the DBRN was performed in asymptomatic participants enrolled from March to August 2021. DBRN alignment was evaluated by measuring angles of the nerve in maximal pronation and maximal supination of the forearm independently by two musculoskeletal radiologists. Forearm range of motion and biometric measurements were recorded. Student t, Shapiro-Wilk, Pearson correlation, reliability analyses, and Kruskal-Wallis test were used. RESULTS: The study population included 110 nerves from 55 asymptomatic participants (median age, 37.0 years; age range, 16-63 years; 29 [52.7%] women). There was a statistically significant difference between the DBRN angle in maximal supination and maximal pronation (Reader 1: 95% CI: 5.74, 8.21, p < 0.001, and Reader 2: 95% CI: 5.82, 8.37, p < 0.001). The mean difference between the angles in maximal supination and maximal pronation was approximately 7° for both readers. ICC was very good for intraobserver agreement (Reader1: r ≥ 0.92, p < 0.001; Reader 2: r ≥ 0.93, p < 0.001), as well as for interobserver agreement (phase 1: r ≥ 0.87, p < 0.001; phase 2: r ≥ 0.90, p < 0.001). CONCLUSION: The extremes of the rotational movement of the forearm affect the longitudinal morphology and anatomic relationships of the DBRN, primarily demonstrating the convergence of the nerve towards the SASM in maximal pronation and divergence in maximal supination.

Osteoartropatia hipertrófica secundária ao carcinoma broncogênico (síndrome de Pierre-Marie-Bamberger) / Hyperthrophic osteoarthropathy associated with bronchogenic carcinoma (Pierre-Marie-Bamberger syndrome)

Descreveremos um raro e memorável caso de osteoartropatia hipertrófica (OAH), cujos sinais e sintomas osteoarticulares da síndrome conduzem ao diagnóstico de adenocarcinoma de pulmão em uma paciente assintomática respiratória. Discutiremos também as diversas particularidades da síndrome, fazendo uma revisão da literatura. Nesta revisão, destacaremos alguns dos novos aspectos de sua obscura etiopatogenia, seu diagnóstico diferencial com doenças reumáticas clássicas e os achados singulares da ressonância magnética, que podem, inclusive, preceder os do RX convencional.

Magnetic resonance imaging of knee instability.

Patellar retinaculum and cruciate and collateral ligaments are major passive stabilizers of the knee joint. Injuries to these ligaments may alter the overall articular motion and lead to instability. Experienced as a sense of the knee "giving way," instability is a predisposing factor for recurring injuries and osteoarthritis. This section presents a practical imaging approach to knee instability based on a major injury to a specific ligament, with routine radiographic and magnetic resonance imaging findings discussed in detail. Common patterns of multiple ligamentous injuries are noted in appropriate subsections.

Hip arthropathy in a patient with primary hemochromatosis: MR imaging findings with pathologic correlation.

Arthropathy is a major clinical manifestation in primary hemochromatosis, typically affecting the metacarpophalangeal joints. Hip arthropathy is not uncommon, with radiologic features resembling osteoarthritis or calcium pyrophosphate dihydrate (CPPD) crystal deposition disease. We describe the MR imaging findings of the hip in a patient with severe hip arthropathy and primary hemochromatosis and correlate them with the histopathologic findings. MR imaging showed severe degenerative changes, with large subchondral cysts and subchondral sclerosis in the femoral head and acetabulum. There was conspicuous correlation between MR imaging and pathologic findings of the resected femoral head. However, MR imaging failed to reveal intra-articular iron.

Monoarticular arthritis.

This article described many of the causes of monoarticular arthritis that are encountered in clinical practice. Although radiologists have relied on conventional radiography and bone scintigraphy, additional imaging methods have been introduced, such as MR imaging, CT scanning, and US. These methods improve visualization of intra-articular and periarticular soft tissue structures and are helpful in the guidance of arthrocentesis, drainage procedures, or percutaneous biopsies. Imaging findings always should be correlated with clinical abnormalities, and, when appropriate, joint fluid analysis.

MR imaging and MR arthrography of the postoperative shoulder: spectrum of normal and abnormal findings.

The postoperative shoulder may be evaluated with various imaging modalities, including radiography, ultrasonography, computed tomography, and magnetic resonance (MR) imaging, each of which has advantages and disadvantages. For optimal soft-tissue visualization, MR imaging and MR arthrography are widely used. Several factors, however, may decrease the accuracy of MR imaging in the evaluation of the postoperative shoulder. These factors include surgical distortions of native anatomy, changes in the signal intensity of tissues, and image degradation caused by metallic artifacts. To maximize the accuracy of MR imaging, the radiologist must select the most appropriate pulse sequences and techniques for the given anatomic structure and the suspected postoperative condition. To avoid magnetic susceptibility artifacts at MR imaging, inversion recovery may be used instead of fat saturation, and fast spin-echo sequences may be used instead of conventional spin-echo sequences or gradient-echo sequences. MR arthrography is most useful for optimal delineation of the rotator cuff, capsulolabral structures, and tendon defects. To achieve accurate image interpretation, the radiologist must be familiar with the arthroscopic and the open surgical techniques currently used to repair internal derangements of the glenohumeral joint, as well as with the typical imaging findings in each postoperative situation.

Role of proton magnetic resonance spectroscopy in the diagnosis of gliomatosis cerebri: a unique pattern of normal choline but elevated Myo-inositol metabolite levels.

A patient with histologically proven gliomatosis cerebri presented with a normal choline level but a markedly abnormal elevated myo-inositol level on magnetic resonance (MR) spectroscopy. We describe the case presentation, imaging findings (in particular, the unique MR spectroscopic pattern), and their significance regarding the diagnosis of this relatively rare neoplasm.

Lesser metatarsophalangeal joints: standard MR imaging, MR arthrography, and MR bursography--initial results in 48 cadaveric joints.

PURPOSE: To delineate the normal magnetic resonance (MR) imaging anatomy of the lesser metatarsophalangeal (MTP) joints in a cadaveric model and compare the MR arthrographic and MR bursographic findings with the standard MR imaging findings. MATERIALS AND METHODS: T1-weighted spin-echo MR imaging of 48 lesser MTP joints of 12 cadaveric feet was performed. The specimens were subsequently evaluated with MR arthrography, MR bursography, or both examinations. Musculoskeletal radiologists evaluated standard MR images to determine the normal appearances of the joint structures, especially the fibrous capsule, plantar plate, and collateral ligament complex (CLC). Signal intensity, morphology, joint thickness, relationships with adjacent structures, and best plane for analysis were analyzed. The contrast material-enhanced (ie, arthrographic and bursographic) MR imaging findings were compared with the standard MR imaging findings. RESULTS: The coronal plane was best for simultaneous depiction of the fibrous capsule, plantar plate, and collateral ligament complex and for assessment of the relationship between the CLC and the plantar plate. The sagittal plane was best for analysis of the bone attachments of the plantar plate and the transverse plane for evaluation of the CLC attachment sites in the phalanges. MR arthrography enabled identification of the bare areas and recesses of the joints, better delineation of the plantar plate articular surface, and better evaluation of the integrity of the soft-tissue components of the joints. Compared with the other examinations, MR bursography did not help improve these evaluations. CONCLUSION: MR imaging is an excellent examination for delineating the anatomy of the lesser MTP joints. Compared with standard MR imaging, only MR arthrography helps improve visualization of the fibrous capsule, plantar plate, and CLC of the lesser MTP joints.

Metatarsophalangeal joint of the great toe: normal MR, MR arthrographic, and MR bursographic findings in cadavers.

OBJECTIVE: To demonstrate the normal anatomy of the metatarsophalangeal (MTP) joint of the great toe with MR imaging, MR arthrography, and MR bursography. MATERIALS AND METHODS: MR images of 12 cadaveric MTP joints of the great toe were obtained before and after arthrography, busography, or both. The MR appearances of all articular and periarticular structures were analyzed and correlated with those seen on anatomic sections. RESULTS: The sesamoid bones and ligaments, the deep transverse metatarsal ligament, and the tendon attachments of the abductor and adductor hallucis muscles were seen best in the coronal plane. The sagittal plane was best for evaluating the plantar plate, the articular cartilage, and the tendon attachments of the flexor and extensor hallucis brevis muscles. The main collateral ligaments were evaluated best in the axial plane. MR arthrography improved the visualization of all articular and periarticular structures except the collateral ligament complexes. MR bursography did not enhance the visualization of these structures. CONCLUSIONS: MR imaging and MR arthrography allow accurate visualization of the important anatomic structures in and about the MTP joint of the great toe.