Imaging of lower extremity infections: predisposing conditions, atypical infections, mimics, and differentiating features.

Imaging evaluation for lower extremity infections can be complicated, especially in the setting of underlying conditions and with atypical infections. Predisposing conditions are discussed, including diabetes mellitus, peripheral arterial disease, neuropathic arthropathy, and intravenous drug abuse, as well as differentiating features of infectious versus non-infectious disease. Atypical infections such as viral, mycobacterial, fungal, and parasitic infections and their imaging features are also reviewed. Potential mimics of lower extremity infection including chronic nonbacterial osteomyelitis, foreign body granuloma, gout, inflammatory arthropathies, lymphedema, and Morel-Lavallée lesions, and their differentiating features are also explored.

Lower extremity infections: Essential anatomy and multimodality imaging findings.

In modern practice, imaging plays an integral role in the diagnosis, evaluation of extent, and treatment planning for lower extremity infections. This review will illustrate the relevant compartment anatomy of the lower extremities and highlight the role of plain radiographs, CT, US, MRI, and nuclear medicine in the diagnostic workup. The imaging features of cellulitis, abscess and phlegmon, necrotizing soft tissue infection, pyomyositis, infectious tenosynovitis, septic arthritis, and osteomyelitis are reviewed. Differentiating features from noninfectious causes of swelling and edema are discussed.

Neuroimaging and neurologic findings in COVID-19 and other coronavirus infections: A systematic review in 116 patients.

Various neurologic syndromes have been described in patients with COVID-19 and other coronavirus infections. In this paper, we systematically reviewed the available imaging findings of patients diagnosed with neurological symptoms associated with coronavirus infections. Diverse radiologic results in the context of different neurologic presentations have been demonstrated using CT and MRI. While many patients have normal imaging evaluations, some patients present with intra-axial and extra-axial abnormalities. Stroke (both ischemic and hemorrhagic), encephalomyelitis, meningitis, demyelinating disorders such as acute disseminated encephalomyelitis (ADEM), and encephalopathy have been reported. Familiarity with these radiologic patterns will guide radiologists and referring clinicians to consider coronavirus infections in patients with worsening or progressive neurologic findings, particularly during the current COVID-19 pandemic. As data on this topic is very limited, further research and investigation are required.

The value of (18) F-fluorodeoxyglucose positron emission tomography for prediction of treatment response in gastrointestinal stromal tumors: a systematic review and meta-analysis.

BACKGROUND: Early detection of response to treatment is critically important in gastrointestinal stromal tumors (GIST). Therefore, the present systematic review and meta-analysis assessed the value of (18) f-fluorodeoxyglucose positron emission tomography ((18) FDG-PET) on prediction of therapeutic response of GIST patients to systemic treatments. METHODS: The literature search was conducted using PubMed, SCOPUS, Cochrane, and Google Scholar databases, and review article references. Eligible articles were defined as studies included confirmed GIST patients who underwent (18) FDG-PET as well as assessing the screening role of it. RESULTS: Finally, 21 relevant articles were included. The analysis showed the pooled sensitivity and specificity of 18FDG-PET in evaluation of response to treatment of GIST patient were 0.90 (95% CI: 0.85-0.94; I(2) = 52.59, P = 0.001) and 0.62 (95% CI: 0.49-0.75; I(2) = 69.7, P = 0.001), respectively. In addition, the pooled prognostic odds ratio of (18) FDG-PET for was 14.99 (95% CI, 6.42-34.99; I(2) = 100.0, P < 0.001). The Meta regression showed that sensitivity of (18) FDG-PET was higher if the sample size of study was equal or more than 30 cases (sensitivity = 0.93; 95% CI: 0.89-0.97), when using PET/CT (sensitivity = 0.92; 95% CI: 0.89-0.97), and self-design criteria (sensitivity = 0.93; 95% CI: 0.87-1.0). CONCLUSION: The present meta-analysis showed (18) FDG-PET has a significant value in predicting treatment response in GIST patients.

PET Molecular Imaging in Breast Cancer: Current Applications and Future Perspectives.

Positron emission tomography (PET) plays a crucial role in breast cancer management. This review addresses the role of PET imaging in breast cancer care. We focus primarily on the utility of 18F-fluorodeoxyglucose (FDG) PET in staging, recurrence detection, and treatment response evaluation. Furthermore, we delve into the growing interest in precision therapy and the development of novel radiopharmaceuticals targeting tumor biology. This includes discussing the potential of PET/MRI and artificial intelligence in breast cancer imaging, offering insights into improved diagnostic accuracy and personalized treatment approaches.

Total Body PET/CT: A Role in Musculoskeletal Diseases.

Recent advancements in PET technology have culminated in the development of total-body PET (TB-PET) systems, which overcome many limitations of traditional scanners. These TB-PET scanners, while still becoming widely available, represent the forefront of clinical imaging across numerous medical institutions worldwide. Early clinical applications have demonstrated their enhanced image quality, precise lesion quantification, and overall superior performance relative to conventional scanners. The capabilities of TB-PET technology, including extended scan range, ultrahigh sensitivity, exceptional temporal resolution, and dynamic imaging, offer significant potential to tackle unresolved clinical challenges in medical imaging. In this discussion, we aim to explore the emerging applications, opportunities, and future perspectives of TB-PET/CT in musculoskeletal disorders (MSDs). Clinical applications for both oncologic and non-oncologic musculoskeletal diseases are discussed, including inflammatory arthritis, infections, osteoarthritis, osteoporosis, and skeletal muscle disorders. From the ability to visualize small musculoskeletal structures and the entire axial and appendicular skeleton, TB-PET shows significant potential in the diagnosis and management of MSD conditions as it becomes more widely available.

Aging Muscles, Myositis, Pain, and Peripheral Neuropathies: PET Manifestations in the Elderly.

Advancing age significantly affects the structural and functional characteristics of organs and tissues, including the peripheral nervous system (PNS) and musculoskeletal system. PET molecular imaging systems offer the ability to assess the metabolic and quantitative effects due to nerve and muscle injuries, which has the potential to impact clinical management of aged subjects. Here, we aim to describe some features of molecular imaging PET systems using different tracers and methods of imaging in musculoskeletal disorders and peripheral neuropathies commonly seen in elderly patients.

Clinical Applications of PET in Evaluating the Aging Spine.

Back pain is a common health complaint that contributes globally to medical burden and costs, particularly in elderly populations. Nuclear medicine techniques using PET tracers offer diagnostic information about various spine disorders, including malignant, degenerative, inflammatory, and infectious diseases. Herein, the authors briefly review applications of PET in the evaluation of spine disorders in elderly patients.

Update on Positron Emission Tomography/Magnetic Resonance Imaging: Cancer and Inflammation Imaging in the Clinic.

Hybrid PET/MRI is highly valuable, having made significant strides in overcoming technical challenges and offering unique advantages such as reduced radiation, precise data coregistration, and motion correction. Growing evidence highlights the value of PET/MRI in broad clinical aspects, including inflammatory and oncological imaging in adults, pregnant women, and pediatrics, potentially surpassing PET/CT. This newly integrated solution may be preferred over PET/CT in many clinical conditions. However, further technological advancements are required to facilitate its broader adoption as a routine diagnostic modality.

Advantages and Applications of Total-Body PET Scanning.

Recent studies have focused on the development of total-body PET scanning in a variety of fields such as clinical oncology, cardiology, personalized medicine, drug development and toxicology, and inflammatory/infectious disease. Given its ultrahigh detection sensitivity, enhanced temporal resolution, and long scan range (1940 mm), total-body PET scanning can not only image faster than traditional techniques with less administered radioactivity but also perform total-body dynamic acquisition at a longer delayed time point. These unique characteristics create several opportunities to improve image quality and can provide a deeper understanding regarding disease detection, diagnosis, staging/restaging, response to treatment, and prognostication. By reviewing the advantages of total-body PET scanning and discussing the potential clinical applications for this innovative technology, we can address specific issues encountered in routine clinical practice and ultimately improve patient care.

Black Fungus and beyond: COVID-19 associated infections.

Globally, many hospitalized COVID-19 patients can experience an unexpected acute change in status, prompting rapid and expert clinical assessment. Superimposed infections can be a significant cause of clinical and radiologic deviations in this patient population, further worsening clinical outcome and muddling the differential diagnosis. As thrombotic, inflammatory, and medication-induced complications can also trigger an acute change in COVID-19 patient status, imaging early and often plays a vital role in distinguishing the cause of patient decline and monitoring patient outcome. While the common radiologic findings of COVID-19 infection are now widely reported, little is known about the clinical manifestations and imaging findings of superimposed infection. By discussing case studies of patients who developed bacterial, fungal, parasitic, and viral co-infections and identifying the most frequently reported imaging findings of superimposed infections, physicians will be more familiar with common infectious presentations and initiate a directed workup sooner. Ultimately, any abrupt changes in the expected COVID-19 imaging presentation, such as the presence of new consolidations or cavitation, should prompt further workup to exclude superimposed opportunistic infection.

Neuroimaging findings in COVID-19: A narrative review.

In this mini-review, we aim to summarize some of the most common neuroimaging findings seen in patients with COVID-19.

SARS-CoV-2 reinfection: "New baseline" imaging concept in the era of COVID-19.

Recent reports have suggested COVID-19 relapse or reinfection may lead to readmission, which may cause a diagnostic challenge between recently infected patients and reinfections. Compounding this problem is the post-viral lung sequela that may be expected after COVID-19 pneumonia, similar to both SARS and MERS. Although chest imaging may play a role in the diagnosis of primary SARS-CoV-2 infection, reinfection or relapse of COVID-19 will have similar imaging findings. A "new-baseline" imaging can be obtained from COVID-19 patients at the time of hospital discharge or clinical recovery. This new reference can not only determine if readmissions are from relapse or reinfection of COVID-19, resolving COVID-19 or potentially a different viral infection (influenza), but also for long term sequela of COVID-19 lung infection. Strategic use of imaging before discharge may be helpful in the subset of the population at the highest risk of a secondary viral infection such as influenza. Determining the residual abnormalities in post-discharge imaging can guide us in the long-term management of patients for many years to come.

COVID-19 vaccine is here: practical considerations for clinical imaging applications.

Imaging tools are potentially able to provide valuable data regarding the development of an efficient vaccine against viral diseases. Tracking immune cells in vivo by imaging modalities can help us understand the intrinsic behaviors of immune cells in response to vaccine components. Imaging patterns at the vaccination site and draining lymph nodes might provide useful information about the vaccine potency. Besides, serial lung CT imaging has been purposed to evaluate vaccine efficiency regarding its protection against typical lung lesions of viral pneumonias. On the other hand, vaccination causes various confusing radiologic patterns that pose diagnostic challenges for clinicians and pitfalls for reading radiologists. This manuscript reviews potential applications of imaging modalities in the process of vaccine development and also goes over some of the imaging findings/pitfalls following vaccination.

Reopening the country: Recommendations for nuclear medicine departments.

The best practices for nuclear medicine departments to operate safely during the COVID-19 pandemic have been debated in the literature recently. However, as many governments have started to ease restrictions in activity due to COVID-19, a set of guidelines is needed to resume routine patient care throughout the world. The nonessential or elective procedures which were previously postponed or canceled during the COVID-19 pandemic will gradually restart in the following weeks despite the continued risks. In this paper, we aim to review some of the most effective general precautions to restart the regular nuclear medicine operations safely.

Theranostic Agents in Musculoskeletal Disorders.

Theranostic-based strategies, combining therapeutic and diagnostic properties of a single agent, have gained enormous attention in the past few years. Today, various multifunctional theranostic modalities have been examined, using different bioactive targeting, for the detection, quantifying, and monitoring of therapy response in different pathologies. Herein we review the newly emerging approaches in theranostic nanomedicine for the detection and therapy for musculoskeletal disorders to provide valuable insights for developing more efficient agents for clinical use. Some potential preclinical applications of radionuclide nanotheranostic agents are described in rheumatoid arthritis, osteoarthrosis, multiple myeloma, and neoplastic diseases.

Coronavirus Disease 2019 (COVID-19) in Molecular Imaging: A Systematic Review of Incidental Detection of SARS-CoV-2 Pneumonia on PET Studies.

There have been several reports of the incidental detection of severe acute respiratory syndrome coronavirus 2 pneumonia on positron emission tomography/computed tomography (PET/CT) studies, which represent the potential role of molecular imaging in the detection and management of coronavirus disease 2019. Here, we systematically review the value of PET/CT in this setting. We conducted a systematic search on June 23, 2020, for PET studies with findings suggestive of coronavirus disease 2019. Web of Science, PubMed, Scopus, EMBASE, and Google Scholar databases were used. Patients with at least one PET/CT imaging evaluation were included in the study. Fifty-two patients in 30 publications with a mean age of 60 ± 12.74 (age range; 27-87) were included in this study, of which 28 (53.8%) were male, and 19 (36.5%) were female. In 5 (9.7%) patients, gender was not reported. PET/CT was performed with 18F-fluorodeoxyglucose for 48 (92.3%), 18F-choline for 3 (5.8%), and 68Ga-PSMA for 1 (1.9%) patients. The mean SUV max of pulmonary lesions with 18F-fluorodeoxyglucose uptake was 4.9 ± 2.3. Moreover, 39 (75%) cases had an underlying malignancy, including 18 different type of primary cancers and 6 (11.5%) patients with metastatic disease. The most common pulmonary findings in PET/CT were bilateral hypermetabolic ground-glass opacities in 39 (75%), consolidation in 18 (34.6%), and interlobular thickening in 4 (7.6%). In addition, mediastinal 14 (27%) and hilar 10 (19.2%) lymph node involvement with increased metabolic activity was frequently identified. Early diagnosis of severe acute respiratory syndrome coronavirus 2 pneumonia is not only crucial for both appropriate patient management but also helps to ensure appropriate postexposure precautions are implemented for the department and hospital staff and those who have been in contact with the patient.

Chest-CT findings of COVID-19 in patients with pre-existing malignancies; a pictorial review.

As of April 17th, 2020, more than 2,190,010 COVID-19 cases with 147,010 deaths have been recorded worldwide. It has been suggested that a high mortality rate occurs in patients with severe disease and is associated with advanced age and underlying comorbidities, such as malignancies. To the best of our knowledge, no study has been conducted to evaluate chest CT features in patients with malignancy and concomitant COVID-19 infection. In fact, the imaging findings can be challenging and have not yet been fully understood in this setting. In this manuscript, we go over imaging findings in chest CT of patients with COVID-19 and known cancer. With the ongoing COVID-19 pandemic and exponentially increasing incidence throughout the world, in at-risk and vulnerable populations such as patients with known malignancies, infection with SARS-CoV-2 should be included in the differential considerations even with atypical image pictures. Detection of superimposed infection in patients with cancers who present with pulmonary infiltrations warrant correlation with clinical picture, contact history, and RT-PCR confirmatory testing.

Imaging Findings of SARS-CoV-2 Infection in Pediatrics: A Systematic Review of Coronavirus Disease 2019 (COVID-19) in 850 Patients.

RATIONALE AND OBJECTIVES: Children with COVID-19 seem to have a relatively milder disease and better prognosis; however, severe disease or death could still occur in this age group. Although the knowledge on the clinical and epidemiology of COVID-19 in pediatric patients is being accumulated rapidly, relevant comprehensive review on its radiological manifestations is still lacking. The present article reviews the radiological characteristics of COVID-19 in pediatrics, based on the previous studies. MATERIALS AND METHODS: We conducted a systematic literature search for published articles by using Medline, Scopus, Google Scholar and Embase online databases. All studies describing CT findings of COVID-19 in pediatrics (<18years) were included. RESULTS: A total of 39 studies with 850 pediatric patients were reviewed. 225 (26.5%) of patients had normal CT findings. Ground-glass opacities and consolidations were the most common CT abnormalities (384/625, 61.5%). Other findings were halo sign, interstitial opacities, bronchial wall thickening, and crazy-paving sign. Approximately 55% of patients had unilateral pulmonary findings. Most studies found peripheral and lower-lobe distribution to be a prominent imaging finding. CONCLUSION: Our study showed that imaging findings in children were often milder and more focal than adults, typically as ground-glass opacities and consolidations with unilateral lower-lobe predominance, which have been regressed during the recovery time. A balance must be struck between the risk of radiation and the need for chest CT. If still necessary, low-dose CT is more appropriate in this age group. Albeit, due to the limited number of reported pediatrics with COVID-19, and the lack of consistency in CT descriptors, further work is still needed in this regard.

Potential Applications of PET Scans, CT Scans, and MR Imaging in Inflammatory Diseases: Part II: Cardiopulmonary and Vascular Inflammation.

Detecting inflammation is among the most important aims of medical imaging. Inflammatory process involves immune system activity and local tissue response. The role of PET with fludeoxyglucose F 18 has been expanded. Systemic vasculitides and cardiopulmonary inflammatory disorders constitute a wide range of diseases with multisystemic manifestations. PET with fludeoxyglucose F 18 is useful in their diagnosis, assessment, and follow-up. This article provides an overview of the current status and potentials of hybrid molecular imaging in evaluating cardiopulmonary and vascular inflammatory diseases focusing on the potential for PET with fludeoxyglucose F 18/MR imaging and PET/CT scans.