Imaging spectrum of atraumatic muscle disorders: a radiologist's guide.

Atraumatic muscle disorders comprise a very wide range of skeletal muscle diseases, including metabolic, inflammatory, autoimmune, infectious, ischemic, and neoplastic involvement of the muscles. Therefore, one must take clinical and laboratory data into consideration to elucidate the differential diagnoses, as well as the distribution of the muscle compromise along the body-whether isolated or distributed along the body in a symmetric or asymmetrical fashion. Assessment of muscular disorders often requires imaging investigation before image-guided biopsy or more invasive procedures; therefore, radiologists should understand the advantages and limitations of imaging methods for proper lesion evaluation and be aware of the imaging features of such disorders, thus contributing to proper decision-making and good patient outcomes. In this review, we propose a systematic approach for the assessment of muscle disorders based on their main imaging presentation, dividing them into patterns that can be easily recognized.

Measurement of tibial slope using biplanar stereoradiography (EOS®).

OBJECTIVES: Posterior tibial slope (PTS) is an important anatomic parameter of the knee related to anteroposterior instability. Biplanar stereoradiography allows for simultaneous low-dose acquisition of anteroposterior and lateral views with 3D capability, enabling separate lateral and medial plateau analyses. We aimed to evaluate the possibility and compare the reproducibility of measuring medial and lateral PTS on EOS® images with two different patient positionings and compare it with CT of the knees as the gold standard. METHODS: This is a retrospective study including volunteers who underwent lower limb stereoradiography and knee CT from 01/08/2016 to 07/31/2019. Sixty legs from 30 patients were studied. PTS were measured using stereoradiography and CT by two radiologists. Intraclass correlation was used to calculate intrarater and interrater reproducibilities. Pearson's correlation coefficients were used to calculate the correlation between stereoradiography and CT. We also compared the reproducibility of the stereoradiography of volunteers with 2 different positionings. RESULTS: The mean stereoradiography PTS values for right and left knees were as follows: lateral, 12.2° (SD: 4.1) and 10.1° (SD: 3.5); medial,12.2° (SD: 4.4) and 11.6° (SD: 3.9). CT PTS mean values for right and left knee are as follows: lateral, 10.3° (SD:2.5) and 10.6° (SD: 2.8); medial: 8.7° (SD: 3.7) and 10.4° (SD: 3.5). Agreement between CT and EOS for angles between lateral and medial PTS was good (right, 0.874; left, 0.871). Regarding patient positioning on stereoradiography, interrater and intrarater reproducibilities were greater for patients with nonparallel feet (0.738-0.883 and 0.870-0.975). CONCLUSIONS: Stereoradiography allows for appropriate delineation of tibial plateaus, especially in patients with nonparallel feet, for the purpose of measuring PTS. The main advantage is lower radiation doses compared to radiography and CT.

Musculoskeletal manifestations of COVID-19.

During the COVID-19 pandemic, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infected millions of people worldwide, with acute respiratory distress syndrome (ARDS) being the most common severe condition of pulmonary involvement. Despite its involvement in the lungs, SARS-CoV-2 causes multiple extrapulmonary manifestations, including manifestations in the musculoskeletal system. Several cases involving bone, joint, muscle, neurovascular and soft tissues were reported shortly after pandemic onset. Even after the acute infection has resolved, many patients experience persistent symptoms and a decrease in quality of life, a condition known as post-COVID syndrome or long COVID. COVID-19 vaccines have been widely available since December 2020, preventing millions of deaths during the pandemic. However, adverse reactions, including those involving the musculoskeletal system, have been reported in the literature. Therefore, the primary goal of this article is to review the main imaging findings of SARS-CoV-2 involvement in the musculoskeletal system, including acute, subacute, chronic and postvaccination manifestations.

Clinical and Radiological Results after Endoscopic Treatment for Gluteal Tendon Injuries with a Minimum Follow-Up of 12 Months.

Objectives: The study aimed to evaluate the clinical and radiological results after endoscopic repair of gluteus medius muscle injuries and proposed an anatomical classification for the different injury classes. Methods: A retrospective case series, including patients who had undergone endoscopic repair of the hip abductor tendon. The surgical procedure was standardized. Magnetic resonance imaging (MRI) studies were analyzed, and the injuries were classified into three types: nontransfixing partial-extension (nTPE) tear, transfixing partial-extension (TPE) tear, and transfixing full-extension (TFE) tear. TPE and TFE were considered high-grade tears. The postoperative outcomes were as follows: duration of walking aid requirement, duration of physical therapy, time to return to daily activities, modified Harris Hip score (mHHS) and Nonarthritic Hip Score (NAHS) functional scores, pain visual analog scale (VAS), satisfaction, claudication, Trendelenburg test, and reoperation. Results: Sixteen patients were included (94% women; mean age 65 years), with a mean follow-up of 42 months (12-131, range). Out of the cases with preoperative exams available for analysis, four cases (31%) were nTPE, three (23%) TPE, and six (46%) TFE tears. Thus, 69% of the patients had high-grade injuries. These patients had a higher degree of fat infiltration (P = 0.034), but this was not correlated with inferior postoperative clinical or radiological results. One patient required reoperation due to a recurrent injury. Conclusion: Isolated extra-articular injuries to the tendons of the gluteus medius and minimus evolved satisfactorily after endoscopic repair. Due to the small number of cases, it was not possible to observe differences in outcomes between high-and low-grade injuries.

Prevalence of phalangeal bone marrow edema on MRI before and during the COVID-19 pandemic and correlation with chilblain skin lesions.

OBJECTIVE: The purpose of this study is to establish the prevalence bone marrow edema of the phalanges of the feet and hands before and during the COVID-19 pandemic on MRI studies and correlate with clinically chilblain skin lesions and epidemiological data. METHODS: This observational retrospective study. In patients with confirmed bone marrow edema of the phalanges, epidemiological data and clinical findings were collected, including the history of current or remote COVID-19 infection and vaccination status. The two-proportion test was used to compare the frequency of bone marrow edema in the phalanges before and during the pandemic, and the comparison between the categories variables was performed using the one-proportion test. RESULTS: Of the total of 7215 patients, only 20 presented isolated bone marrow edema of the digits in MRI studies; 2 (0.05%) were found two years before the pandemic's beginning, and 18 (0.64%) after the pandemic's onset, demonstrating an increase of 13-fold in this period. 16 were women with a mean age of 40.3 years and 4 were men with a mean age of 53.5 years. The most frequently reported clinical symptoms by the patients were pain (85.0%), and erythema of the skin (45.0%). Of the 18 patients found after the pandemic's onset, only 27.8% had COVID-19 infections confirmed by RT-PCR before the imaging study, and all cases were mild. CONCLUSION: This study demonstrated a significant increase in the prevalence of bone marrow edema of the phalanges after the onset of the COVID-19 pandemic, particularly in middle-aged and younger women.

Tendon injections - upper extremity.

Imaging-guided tendon procedures aim to reduce pain and increase function by controlling inflammation and stimulating healing. Ultrasound is the preferable guiding modality due to its high resolution and real-time demonstration of the tendinous anatomy and needle positioning. The technique includes appropriate patient positioning, which varies depending on the targeted tendon, as well as sterile and proper draping. For most procedures, we prefer the "in-plane" approach, which demonstrates the entire needle as it advances through different tissue layers. Upper limb injections commonly use corticosteroids and anesthetics with different reported short- and long-term results depending on the tendon treated; better results are obtained in the treatment of tenosynovitis (sliding tendons such as trigger finger and De Quervain's tenosynovitis). Shoulder and elbow tendinopathies (anchor tendons) may also benefit from injections containing irritants or healing stimulants such as dextrose (prolotherapy) and platelet-rich plasma or by the stimulation of healing via tendon perforations (fenestration). The hyaluronic acid injection has also been used in the treatment of both tenosynovitis and tendinopathies. For tendons passing through osteofibrous tunnels, an additional release may be performed, and the techniques are discussed in this review. Therefore, this article provides practicing musculoskeletal radiologists and trainees with a comprehensive review of tendon injection musculoskeletal image-guided procedures.

Chronic nonbacterial osteomyelitis: the role of whole-body MRI.

BACKGROUND: Chronic nonbacterial osteomyelitis (CNO), also known as chronic recurrent multifocal osteomyelitis, is a noninfectious autoinflammatory disorder that occurs primarily in children and adolescents and is characterized by episodic musculoskeletal pain with a protracted course. MAIN BODY: Traditionally, the diagnosis of CNO is made by exclusion and commonly requires bone biopsy to rule out infection and malignancy. However, bone biopsy may be avoided when imaging and clinical characteristic features are present, such as multifocal bone lesions at typical sites, no constitutional symptoms and no signs of infection in laboratory test results. Whole-body magnetic resonance imaging (WB-MRI) can assess signs of acute and chronic inflammation and enables the detection of CNO typical patterns of lesion location and distribution, thereby helping to exclude differential diagnosis. The goal of the present study paper is to review the main clinical and imaging aspects of the disease with emphasis on the role of WB-MRI in the diagnosis, assessment of disease burden and follow-up monitoring. CONCLUSION: Radiologists need to be familiar with the imaging features to suggest the diagnosis as the early therapy may help to avoid irreversible secondary damage of skeletal system.

Stener-like lesions in the hand, knee and foot: a review of anatomy, mechanism of injury and imaging evaluation.

A Stener lesion is a displaced tear of the ulnar collateral ligament in the metacarpophalangeal joint of the thumb in which the adductor pollicis aponeurosis is positioned between the retracted ligament and the injury site, preventing natural healing. This lesion was first described in 1962, and since then, both radiologists and orthopedists have considered it important to treat surgically. Although this lesion was originally described in the thumb, this injury mechanism can occur in other joints of the hand, knee, and foot. The purpose of this study was to review the relevant aspects of classic Stener lesions of the thumb, as well as other Stener-like lesions, including their anatomy, mechanisms of lesion formation and imaging features. The Stener-like injury pattern often necessitates surgical repair or reconstruction; thus, it is essential that radiologists recognize and report the different patterns of injury.

Bone Marrow Lesion: Image, Clinical Presentation, and Treatment.

In this article, the cause, histology, imaging characteristics, clinical presentation, and treatment of these lesions are thoroughly discussed. Bone marrow edema is the generic term classically used to describe the high-signal-intensity alterations detected on magnetic resonance fluid-sensitive sequences. The significance of bone marrow edema for the patient's clinical condition and the prognosis of the affected joint is being increasingly investigated and discussed, and situations characterized by subchondral insufficiency are receiving increasing attention. More recent studies found some important correlations between bone marrow lesions and patient's pain and osteoarthritis progression. Conservative treatment is based on anti-inflammatory and analgesic uses according to the patient's pain, combined with reduced load on the affected limb. Regarding surgical treatment, subchondroplasty is an option still in development, albeit with promising initial results.