Musculoskeletal Manifestations of COVID-19: Currently Described Clinical Symptoms and Multimodality Imaging Findings.

COVID-19, the clinical syndrome produced by infection with SARS-CoV-2, can result in multisystem organ dysfunction, including respiratory failure and hypercoagulability, which can lead to critical illness and death. Musculoskeletal (MSK) manifestations of COVID-19 are common but have been relatively underreported, possibly because of the severity of manifestations in other organ systems. Additionally, patients who have undergone sedation and who are critically ill are often unable to alert clinicians of their MSK symptoms. Furthermore, some therapeutic measures such as medications and vaccinations can worsen existing MSK symptoms or cause additional symptoms. Symptoms may persist or occur months after the initial infection, known as post-COVID condition or long COVID. As the global experience with COVID-19 and the vaccination effort increases, certain patterns of MSK disease involving the bones, muscles, peripheral nerves, blood vessels, and joints have emerged, many of which are likely related to a hyperinflammatory host response, prothrombotic state, or therapeutic efforts rather than direct viral toxicity. Imaging findings for various COVID-19-related MSK pathologic conditions across a variety of modalities are being recognized, which can be helpful for diagnosis, treatment guidance, and follow-up. The online slide presentation from the RSNA Annual Meeting is available for this article. ©RSNA, 2022.

Magnetic resonance imaging of musculoskeletal infections.

Magnetic resonance imaging (MRI) is a powerful imaging modality in the evaluation of musculoskeletal (MSK) soft tissue, joint, and bone infections. It allows prompt diagnosis and assessment of the extent of disease, which permits timely treatment to optimize long-term clinical outcomes. MRI is highly sensitive and specific in detecting the common findings of MSK infections, such as superficial and deep soft tissue oedema, joint, bursal and tendon sheath effusions, lymphadenopathy, bone marrow oedema, erosive bone changes and periostitis, and bone and cartilage destruction and sequestration. Contrast-enhanced MRI allows detection of non-enhancing fluid collections and necrotic tissues, rim-enhancing abscesses, heterogeneously or diffusely enhancing phlegmons, and enhancing active synovitis. Diffusion-weighted imaging (DWI) is useful in detecting soft-tissue abscesses, particularly in patients who cannot receive gadolinium-based intravenous contrast. MRI is less sensitive than computed tomography (CT) in detecting soft-tissue gas. This article describes the pathophysiology of pyogenic MSK infections, including the route of contamination and common causative organisms, typical MR imaging findings of various soft tissue infections including cellulitis, superficial and deep fasciitis and necrotizing fasciitis, pyomyositis, infectious bursitis, infectious tenosynovitis, and infectious lymphadenitis, and of joint and bone infections including septic arthritis and osteomyelitis (acute, subacute, and chronic). The authors also discuss MRI findings and pitfalls related to infected hardware and diabetic foot infections, and briefly review standards of treatment of various pyogenic MSK infections.

Magnetic resonance imaging of rheumatological diseases.

Magnetic resonance imaging (MRI) is extremely useful in the early diagnosis of rheumatologic diseases, as well as in the monitoring of treatment response and disease progression to optimize long-term clinical outcomes. MRI is highly sensitive and specific in detecting the common findings in rheumatologic diseases, such as bone marrow oedema, cartilage disruption, articular erosions, joint effusions, bursal effusions, tendon sheath effusions, and synovitis. This imaging modality can demonstrate structural changes of cartilage and bone destruction years earlier than radiographs. Rheumatoid arthritis, crystal deposition diseases (including gouty arthropathy and calcium pyrophosphate deposition disease), seronegative spondyloarthropathies (including psoriatic arthritis, reactive arthritis, ankylosing spondylitis), and osteoarthritis have characteristic appearances on MRI. Contrast-enhanced MRI and diffusion-weighted imaging can provide additional evaluation of active synovitis. This article describes the MRI findings of normal joints, as well as the pathophysiological mechanisms and typical MRI findings of rheumatoid arthritis, gouty arthritis, calcium pyrophosphate deposition disease, psoriatic arthritis, reactive arthritis, ankylosing spondylitis, and osteoarthritis.

Magnetic Resonance Imaging in the Evaluation of Female Infertility.

Pelvic MRI plays an important adjunctive role in the clinical workup of female infertility. Hysterosalpingography is the first line imaging modality in evaluation of female infertility, and hysterosalpingo-contrast sonography can also be used to evaluate both the uterine cavity and fallopian tubes. Pelvic MRI can be helpful in the workup of female infertility, particularly in cases of Mullerian duct anomalies, fibroids, adenomyosis, endometriosis, and tubal disease. These conditions and their appearance on imaging will be reviewed in this article.

Partial Renal Transplant Torsion as a Cause of Abdominal Pain.

Allograft torsion is a rare but potentially devastating outcome of renal transplantation. Patients typically present with an acute onset of abdominal pain, though symptoms are non-specific and can easily be missed in favor of more common diagnoses. Imaging, in particular ultrasound and computed tomography, can aid in the diagnosis of renal transplant torsion by demonstrating characteristic features, and once recognized immediate surgery is typically performed in an attempt to salvage the allograft. However, renal transplant torsion needs not be an acute event; patients can instead present with chronic, waxing, and waning symptoms if the allograft undergoes partial or intermittent torsion. The aforementioned characteristic imaging findings may not be present in this situation. It is essential to recognize partial, intermittent torsion as well, for which imaging can again play a role.

Imaging of Intrahepatic Cholangiocarcinoma.

Cholangiocarcinoma is the second most common primary hepatic malignancy and is a heterogeneous tumor of biliary epithelium. We discuss the risk factors, anatomic classification of cholangiocarcinoma (CC) as well as the different morphologic subtypes of CC. Imaging findings of CC on different modalities are described, focusing on intrahepatic CC. Recently recognized imaging features that carry prognostic significance, such as a worse prognosis in tumors that have more desmoplastic stroma, are detailed. Other benign and malignant entities that should be considered in the differential diagnosis of CC will also be discussed.

Paraspinal Fat Stranding as an Unexpected Finding on Body Computed Tomography: A Key to Early Detection of Spinal Osteomyelitis.

OBJECTIVE: At present, early detection of spinal osteomyelitis is a challenge. Patients may present with non-specific symptoms and diagnostic imaging studies may be obtained for seemingly unrelated complaints. Paraspinal fat stranding on body computed tomography (CT) as a sign of osteomyelitis is easily overlooked and has not been reported in the literature to our knowledge. The purpose of this study is to review findings on body CT that points to unsuspected spinal osteomyelitis. MATERIAL AND METHODS: A retrospective review of patients with spinal osteomyelitis who also had concomitant chest, abdominal, or pelvic CT scans between August 2013 and February 2017 yielded 10 patients who had confirmed osteomyelitis (ages between 51 and 75, mean age 64.8). Images and medical records were reviewed. RESULTS: The age of the patients ranged from 51 to 75 years (median value, 64). All patients had multiple underlying medical illnesses, and half of them had a known preceding infection such as sepsis or urinary tract infection. At presentation, three patients had a fever and two patients had neurologic deficits. Seven out of eight patients had elevated C-reactive protein and erythrocyte sedimentation rate, five patients had leukocytosis, and four patients had positive blood cultures. Paravertebral fat stranding and endplate erosions were observed in 9 and 6 cases, respectively, on initial body CT for unrelated indications, and subsequent magnetic resonance imaging confirmed osteomyelitis discitis. CONCLUSION: Clinically significant, but initially unsuspected, spinal pathology such as osteomyelitis may present on body CT scans. Earlier diagnosis of spinal osteomyelitis can be made by performing a focused evaluation of the paraspinal soft tissues and including osteomyelitis in the differential diagnosis, particularly in high-risk patients.

Hepatic actinomycosis - A potential mimicker of malignancy.

Actinomycosis is a rare granulomatous disease caused by commensal bacteria (Actinomycetaceae family) of the oropharynx, gastrointestinal, and urogenital tract. Infection most commonly involves the cervicofacial region but less frequently the abdominal region, typically secondary to a disruption of normal gastrointestinal mucosa. We present a patient with vague symptoms of fevers and myalgias and a recent diagnosis of rectal cancer. On CT, there were multiple centrally hypoattenuating hepatic lesions suspicious for metastasis vs abscesses, also confirmed by ultrasound. Initial image guided biopsy was non-diagnostic. Laparoscopic resection of one of the hepatic lesions showed pus consistent with an abscess. No organisms were identified by culture and a sample was sent to an outside laboratory for genomic polymerase chain reaction (PCR) analysis where Actinomyces DNA was isolated. This case report highlights a rare presentation of primary hepatic Actinomycosis and some of the challenges in diagnosing Actinomycosis due to its variable clinical and radiological manifestations and lack of diagnostic sensitivity by traditional microscopy and culture based techniques.

Texture analysis of placental MRI: can it aid in the prenatal diagnosis of placenta accreta spectrum?

PURPOSE: To determine if texture analysis can differentiate placenta accreta spectrum (PAS) from normal placenta on MRI. METHODS: We performed retrospective image analysis of 80 patients, comprised of 46 patients with PAS and 34 patients without PAS. Histopathology was used as the reference standard. Sagittal single shot fast spin echo T2-weighted MRI sequences acquired from a single institution were analyzed. Placental heterogeneity was quantified using in-house software on a Matlab platform, including the standard deviation of pixel intensity, coefficient of variation, gray-level co-occurrence matrices (GLCM), histogram-oriented gradients (HOG), and fractal analysis with box sizes from 2 to 512. Two-tailed unpaired Student's t test was used with statistical significance of p < 0.05. RESULTS: PAS was associated with higher values for standard deviation of pixel intensity and fractal analysis at every box size. Fractal analysis at box sizes 256 (p = 0.011) and 32 (p = 0.021), and standard deviation of pixel intensity (p = 0.023) were the most statistically significant. Fractal values at box size 256 for PAS was 0.13 versus 0.090 for patients without PAS, while standard deviation of pixel intensity was 3.7 for PAS versus 2.5 for patients without PAS. No statistically significant association between PAS and GLCM, coefficient of variation, and HOG was found. CONCLUSION: Statistically significant differences were found between normal and abnormal groups using standard deviation of pixel intensity and fractal analysis.

Update on Imaging of Knee Arthroplasties: Normal Findings and Hardware Complications.

Total knee arthroplasty (TKA) is the most common joint replacement performed. This article reviews the normal appearance of TKA including the most common types of arthroplasties as well as complications. Common complications at the present time are infection, aseptic loosening, and instability. Rarer complications such as polyethylene wear, periprosthetic fracture, and soft tissue pathology are also discussed. Although the mainstay of imaging is radiographs, newer techniques in TKA imaging such as computed tomography and magnetic resonance imaging are also reviewed.

Radiologic Evaluation of Lower Leg, Ankle, and Foot Fracture Fixation Hardware.

Radiologists should be familiar with basic principles of fracture fixation and the normal imaging appearances of implant constructs and their complications. The surgeon's selection of external fixation, intramedullary nail fixation, open reduction and internal fixation, or some combination depends on patient factors, fracture configuration, injury to the soft tissue envelope, and surgeon experience. Complications including loss of fixation with resultant malalignment, nonunion, infection, and posttraumatic osteoarthritis present additional challenges for the surgeon as well as the radiologist. This article reviews the rationale behind fracture fixation in fractures of the lower leg, ankle, and foot. Examples of postoperative complications are also reviewed.

Posterior dislocation of the long head biceps tendon: a case report, specific radiographic finding, and review of the literature.

Posterior dislocation of the long head of the biceps tendon uncommonly occurs with traumatic shoulder injury. The diagnosis is almost always associated with anterior shoulder dislocation which often cannot be reduced. We present a case of traumatic posterior dislocation of the long head of the biceps tendon with no reported history of shoulder dislocation, but instead a rare and specific radiographic finding. The imaging features are described, the relevant literature reviewed, and salient features discussed.

Spectrum of Voriconazole-Induced Periostitis With Review of the Differential Diagnosis.

OBJECTIVE: Voriconazole is an antifungal medication used primarily for the treatment of Candida and Aspergillus infections. A fairly newly described side effect of long-term voriconazole use is periostitis. The purpose of this article is to describe the main differential consideration-hypertrophic osteoarthropathy-and other differential diagnoses, including venous stasis, thyroid acropachy, and hypervitaminosis A. CONCLUSION: With knowledge of imaging appearance, clinical manifestations, and outcomes, radiologists can make an accurate diagnosis of voriconazole-induced periostitis, and clinical teams can initiate appropriate management.

Constructing and Pilot Testing a Novel Prostate Magnetic Resonance Imaging/Ultrasound Fusion Biopsy Phantom.

OBJECTIVE: To describe the design and build of a novel phantom for magnetic resonance imaging (MRI)/ultrasound (US) fusion biopsy and present pilot testing results from a multicenter urology resident training session. METHODS: We cast our phantom from polyvinylchloride-plastisol that features 10 mm and 5 mm blue clay tumors, a urethral lumen, and an echogenic capsule. T2-weighted images were acquired with a 3T MR750 scanner (GE Healthcare, Boston, MA). Fusion testing was performed on the bkFusion system (BK ultrasound, Peabody, MA) with MIM Symphony software (MIM, Cleveland, OH) and an 18-gauge Bard Monopty disposable gun (Bard, Murray Hill, NJ). Twenty residents from 6 urology programs in Chicago performed proctored user testing. RESULTS: The per phantom material cost was $12. The phantom was compatible with all necessary equipment to create a MRI/US fusion data set. MRI and US imaging characteristics were excellent with hypointense lesions. Image fusion was achieved through both end and side fire ultrasound probes. The phantom allowed for biopsies to be performed, and target lesion hits were confirmed by visual inspection of core samples. 38% (8/21) of urology resident pilot testing participants had previously performed a fusion biopsy. The mean postsession survey scores were (1-10 [best]): realism 9.0, usefulness 9.4, ease of use 9.1, ease of orientation 8.9, and overall experience 9.3. CONCLUSION: This simple and inexpensive phantom allows for training and accuracy testing of MRI/US fusion biopsy hardware and software platforms.

Pancreaticopleural Fistula: A Review of Imaging Diagnosis and Early Endoscopic Intervention.

A 49-year-old male with history of chronic alcohol-induced pancreatitis presented with one month of worsening left pleuritic chest pain and shortness of breath. Chest radiograph demonstrated bilateral pleural effusions. Thoracentesis revealed increased amylase in the pleural fluid. Computed tomography (CT) and magnetic resonance cholangiopancreatography (MRCP) showed a fistula tract between the left pleural cavity and pancreas which was confirmed on endoscopic retrograde cholangiopancreatography (ERCP). Patient was treated with placement of a pancreatic stent with complete resolution of the fistula tract approximately in 9 weeks. A systematic literature search was performed on reported cases with pancreaticopleural fistula (PPF) who underwent early therapeutic endoscopy within the last 10 years. Imaging modalities, particularly CT and MRCP, play essential role in prompt preprocedural diagnosis of PPF. Early therapeutic ERCP is an effective and relatively safe treatment option for PPF, so invasive surgery may be avoided.

Colorectal-Vaginal Fistulas: Imaging and Novel Interventional Treatment Modalities.

Colovaginal and/or rectovaginal fistulas cause significant and distressing symptoms, including vaginitis, passage of flatus/feces through the vagina, and painful skin excoriation. These fistulas can be a challenging condition to treat. Although most fistulas can be treated with surgical repair, for those patients who are not operative candidates, limited options remain. As minimally-invasive interventional techniques have evolved, the possibility of fistula occlusion has enriched the therapeutic armamentarium for the treatment of these complex patients. In order to offer optimal treatment options to these patients, it is important to understand the imaging and anatomical features which may appropriately guide the surgeon and/or interventional radiologist during pre-procedural planning.

Acute diverticulitis in renal transplant patients: should we treat them differently?

BACKGROUND: Current guidelines suggest that transplant patients with acute diverticulitis should be managed aggressively with early operative intervention to reduce morbidity and mortality. This study compared the treatment choices and clinical outcomes between renal transplant patients and immunocompetent patients with acute diverticulitis. METHODS: A retrospective review was performed of all patients who were admitted with acute diverticulitis between 2002 and 2015 at a single academic institution. Patient demographics, comorbidities, physiologic and radiologic disease severity, management, and disease-specific outcomes were recorded and compared between renal transplant patients and immunocompetent patients. Predictors of complications also were analyzed. RESULTS: In the study, 20 renal transplant patients and 134 immunocompetent patients were admitted for acute diverticulitis and were followed for a median time of 36 and 40 months, respectively. Patient demographics were similar between the groups. Transplant patients had significantly more comorbidities. Overall, there were no differences in physiologic disease severity or rates of elective or urgent operation, ostomy, permanent ostomy, duration of stay, 30-day readmission, disease recurrence or disease-specific complications, organ failure, or death. Among patients with complicated disease, renal transplant patients were significantly more likely to undergo an urgent operation and had more complications. On multivariate analysis, undergoing operative therapy remained the sole predictor of complications. CONCLUSION: Nonoperative management of renal transplant patients who present with uncomplicated diverticulitis is safe as outcomes are similar to immunocompetent patients. However, the optimal management of renal transplant patients with complicated diverticulitis remains unclear as both treatment choices and complication rates differed from immunocompetent patients.

Promoting Collaborations Between Radiologists and Scientists.

Radiology as a discipline thrives on the dynamic interplay between technological and clinical advances. Progress in almost all facets of the imaging sciences is highly dependent on complex tools sourced from physics, engineering, biology, and the clinical sciences to obtain, process, and view imaging studies. The application of these tools, however, requires broad and deep medical knowledge about disease pathophysiology and its relationship with medical imaging. This relationship between clinical medicine and imaging technology, nurtured and fostered over the past 75 years, has cultivated extraordinarily rich collaborative opportunities between basic scientists, engineers, and physicians. In this review, we attempt to provide a framework to identify both currently successful collaborative ventures and future opportunities for scientific partnership. This invited review is a product of a special working group within the Association of University Radiologists-Radiology Research Alliance.

Liver Masses: What Physicians Need to Know About Ordering and Interpreting Liver Imaging.

PURPOSE OF REVIEW: This paper reviews diagnostic imaging techniques used to characterize liver masses and the imaging characteristics of the most common liver masses. RECENT FINDINGS: The role of recently adopted ultrasound and magnetic resonance imaging contrast agents will be emphasized. Contrast-enhanced ultrasound is an inexpensive exam which can confirm benignity of certain liver masses without ionizing radiation. Magnetic resonance imaging using hepatocyte-specific gadolinium-based contrast agents can help confirm or narrow the differential diagnosis of liver masses.

Impact of Abdominal Adipose Depots and Race on Risk for Colorectal Cancer: A Case-Control Study.

Visceral adipose tissue (VAT) but not subcutaneous adipose tissue (SAT) is associated with obesity-related diseases including colorectal cancer (CRC). Superficial SAT (SSAT) and deep SAT (DSAT), components of SAT, also appear to independently influence disease risk. These abdominal adipose tissues (AATs) are not extensively studied in connection with CRC and have not been explored in the United States despite known racial variations in body composition. We conducted a case-control study that compared associations between AAT with CRC risk and race of African-American (AA) and non-Hispanic white (NHW) men with incident CRC matched by age, body mass index, and race (N = 158, 79/group). Cross-sectional computed tomography images were used for assessment of AAT. Overall cases and controls had similar VAT areas (140 ± 192 vs 149 ± 152 cm2, P-value = 0.93); however, cases had lower SSAT than controls (88 ± 39 vs 112 ± 65 cm2, P < 0.01). Among controls, AA had significantly lower VAT (114 ± 168 vs 180 ± 167, P < 0.01) than NHW. Conditional logistic regression revealed that AA men with greater SSAT had lower odds for CRC (odds ratio [OR]: 0.24, 95% confidence interval [CI] 0.07-0.85). Our findings indicate that VAT does vary between cases and controls by race; however, this variation is not a risk factor for CRC. The negative association between CRC and SSAT in AA men warrants further investigation.