Overview of F18-FDG uptake patterns in retroperitoneal pathologies: imaging findings, pitfalls, and artifacts.

INTRODUCTION: Retroperitoneum can be the origin of a wide variety of pathologic conditions and potential space for disease spread to other compartments of the abdomen and pelvis. Computed tomography (CT) and magnetic resonance imaging (MRI) are often the initial imaging modalities to evaluate the retroperitoneal pathologies, however given the intrinsic limitations, F18-FDG PET/CT provides additional valuable metabolic information which can change the patient management and clinical outcomes. We highlight the features of retroperitoneal pathologies on F18-FDG PET/CT and the commonly encountered imaging artifacts and pitfalls. The aim of this review is to characterize primary and secondary retroperitoneal pathologies based on their metabolic features, and correlate PET findings with anatomic imaging. CONCLUSION: Retroperitoneal pathologies can be complex, ranging from oncologic to a spectrum of non-oncologic disorders. While crosse-sectional imaging (CT and MRI) are often the initial imaging modalities to localize and characterize pathologies, metabolic information provided by F18-FDG PET/CT can change the management and clinical outcome in many cases.

Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in differentiation of soft tissue sarcoma from benign lesions: a systematic review of literature.

OBJECTIVE: To systematically review the literature assessing the role of Dynamic Contrast-Enhanced Magnetic Resonance Imaging (DCE-MRI) in the differentiation of soft tissue sarcomas from benign lesions. MATERIALS AND METHODS: A comprehensive literature search was performed with the following keywords: multiparametric magnetic resonance imaging, DCE-MR perfusion, soft tissue, sarcoma, and neoplasm. Original studies evaluating the role of DCE-MRI for differentiating benign soft-tissue lesions from soft-tissue sarcomas were included. RESULTS: Eighteen studies with a total of 965 imaging examinations were identified. Ten of twelve studies evaluating qualitative parameters reported improvement in discriminative power. One of the evaluated qualitative parameters was time-intensity curves (TIC), and malignant curves (TIC III, IV) were found in 74% of sarcomas versus 26.5% benign lesions. Six of seven studies that used the semiquantitative approach found it relatively beneficial. Four studies assessed quantitative parameters including Ktrans (contrast transit from the vascular compartment to the interstitial compartment), Kep (contrast return to the vascular compartment), and Ve (the volume fraction of the extracellular extravascular space) in addition to other parameters. All found Ktrans, and 3 studies found Kep to be significantly different between sarcomas and benign lesions. The values for Ve were variable. Additionally, eight studies assessed diffusion-weighted imaging (DWI), and 6 of them found it useful. CONCLUSION: Of different DCE-MRI approaches, qualitative parameters showed the best evidence in increasing the diagnostic performance of MRI. Semiquantitative and quantitative approaches seemed to improve the discriminative power of MRI, but which parameters and to what extent is still unclear and needs further investigation.

Automatic MRI-based rotator cuff muscle segmentation using U-Nets.

BACKGROUND: The rotator cuff (RC) is a crucial anatomical element within the shoulder joint, facilitating an extensive array of motions while maintaining joint stability. Comprised of the subscapularis, infraspinatus, supraspinatus, and teres minor muscles, the RC plays an integral role in shoulder functionality. RC injuries represent prevalent, incapacitating conditions that impose a substantial impact on approximately 8% of the adult population in the USA. Segmentation of these muscles provides valuable anatomical information for evaluating muscle quality and allows for better treatment planning. MATERIALS AND METHODS: We developed a model based on residual deep convolutional encoder-decoder U-net to segment RC muscles on oblique sagittal T1-weighted images MRI. Our data consisted of shoulder MRIs from a cohort of 157 individuals, consisting of individuals without RC tendon tear (N=79) and patients with partial RC tendon tear (N=78). We evaluated different modeling approaches. The performance of the models was evaluated by calculating the Dice coefficient on the hold out test set. RESULTS: The best-performing model's median Dice coefficient was measured to be 89% (Q1:85%, Q3:96%) for the supraspinatus, 86% (Q1:82%, Q3:88%) for the subscapularis, 86% (Q1:82%, Q3:90%) for the infraspinatus, and 78% (Q1:70%, Q3:81%) for the teres minor muscle, indicating a satisfactory level of accuracy in the model's predictions. CONCLUSION: Our computational models demonstrated the capability to delineate RC muscles with a level of precision akin to that of experienced radiologists. As hypothesized, the proposed algorithm exhibited superior performance when segmenting muscles with well-defined boundaries, including the supraspinatus, subscapularis, and infraspinatus muscles.

Imaging of abdominopelvic oncologic emergencies.

With advancements in cancer treatment, the survival rates for many malignancies have increased. However, both the primary tumors and the treatments themselves can give rise to various complications. Acute symptoms in oncology patients require prompt attention. Abdominopelvic oncologic emergencies can be classified into four distinct categories: vascular, bowel, hepatopancreatobiliary, and bone-related complications. Radiologists need to be familiar with these complications to ensure timely diagnosis, which ultimately enhances patient outcomes.

Current Status and Future of Artificial Intelligence in MM Imaging: A Systematic Review.

Artificial intelligence (AI) has attracted increasing attention as a tool for the detection and management of several medical conditions. Multiple myeloma (MM), a malignancy characterized by uncontrolled proliferation of plasma cells, is one of the most common hematologic malignancies, which relies on imaging for diagnosis and management. We aimed to review the current literature and trends in AI research of MM imaging. This study was performed according to the PRISMA guidelines. Three main concepts were used in the search algorithm, including "artificial intelligence" in "radiologic examinations" of patients with "multiple myeloma". The algorithm was used to search the PubMed, Embase, and Web of Science databases. Articles were screened based on the inclusion and exclusion criteria. In the end, we used the checklist for Artificial Intelligence in Medical Imaging (CLAIM) criteria to evaluate the manuscripts. We provided the percentage of studies that were compliant with each criterion as a measure of the quality of AI research on MM. The initial search yielded 977 results. After reviewing them, 14 final studies were selected. The studies used a wide array of imaging modalities. Radiomics analysis and segmentation tasks were the most popular studies (10/14 studies). The common purposes of radiomics studies included the differentiation of MM bone lesions from other lesions and the prediction of relapse. The goal of the segmentation studies was to develop algorithms for the automatic segmentation of important structures in MM. Dice score was the most common assessment tool in segmentation studies, which ranged from 0.80 to 0.97. These studies show that imaging is a valuable data source for medical AI models and plays an even greater role in the management of MM.

Skin Malignancies: Imaging Review with Radiologic-Histopathologic Correlation.

Skin malignancies are commonly encountered as primary or incidental findings. Neoplasms that affect the skin include primary (basal cell carcinoma, squamous cell carcinoma, melanoma, and Merkel cell carcinoma) and secondary (mesenchymal neoplasms, lymphoma, and metastases) tumors. Imaging provides valuable anatomic information (tumor size, depth of involvement, presence of distant metastasis, and data for guiding biopsy) and functional information (metabolic activity and sentinel node mapping data). This information, in addition to biopsy results, improves the histopathologic characterization of tumors and treatment planning. Various histopathologic types of the same entity exhibit different biologic behavior and have different imaging features. Familiarity with the multimodality imaging features, histopathologic characteristics, and various modes of dissemination (direct invasion; perineural, lymphatic, and hematogenous spread) of the most common skin malignancies helps radiologists narrow the differential diagnosis in clinical practice. ©RSNA, 2023 Supplemental material is available for this article. Quiz questions for this article are available through the Online Learning Center.

Editorial on Special Issue "Skeletal Radiology".

Musculoskeletal (MSK) disorders are among the top five contributors to disability-adjusted life years (DALYs) worldwide [...].

Fibroblastic and Myofibroblastic Soft-Tissue Tumors: Imaging Spectrum and Radiologic-Pathologic Correlation.

Fibroblastic and myofibroblastic tumors are a variable group of neoplasms ranging from benign to malignant. These lesions may affect patients of any age group but are more frequently encountered in the pediatric population. Patient clinical presentation depends on the location, growth pattern, adjacent soft-tissue involvement, and pathologic behavior of these neoplasms. In the 2020 update to the World Health Organization (WHO) classification system, these tumors are classified on the basis of their distinct biologic behavior, histomorphologic characteristics, and molecular profiles into four tumor categories: (a) benign (eg, fibrous hamartoma of infancy, nodular fasciitis, proliferative fasciitis, fibroma of the tendon sheath, calcifying aponeurotic fibroma); (b) intermediate, locally aggressive (eg, desmoid fibromatosis); (c) intermediate, rarely metastasizing (eg, dermatofibrosarcoma protuberans, myxoinflammatory fibroblastic sarcoma, low-grade myofibroblastic sarcoma, infantile fibrosarcoma); and (d) malignant (eg, sclerosing epithelioid fibrosarcomas; low-grade fibromyxoid sarcoma; myxofibrosarcoma; fibrosarcoma, not otherwise specified). Detection of various components of solid tumors at imaging can help in prediction of the presence of corresponding histopathologic variations, thus influencing diagnosis, prognosis, and treatment planning. For example, lesions with a greater myxoid matrix or necrotic components tend to show higher signal intensity on T2-weighted MR images, whereas lesions with hypercellularity and dense internal collagen content display low signal intensity. In addition, understanding the radiologic-pathologic correlation of soft-tissue tumors can help to increase the accuracy of percutaneous biopsy and allow unnecessary interventions to be avoided. ©RSNA, 2023 Quiz questions for this article are available in the supplemental material.

Imaging Features of Intraosseous Schwannoma: A Case Series and Review of the Literature.

To characterize the imaging features of patients with pathologically confirmed intraosseous schwannoma (IOS), institutional pathology and imaging databases were searched for IOS cases over a period of 17 years. A musculoskeletal radiologist evaluated all imaging studies. Additionally, a literature search was performed to identify IOS cases that had imaging findings of at least two modalities. Six patients (one female, five males, mean age of 50 ± 14 years) with IOS were identified, with all lesions localized to the lumbosacral region. Radiographic imaging was available in four patients, while all patients underwent CT and MR imaging. Radiographs depicted lytic lesions, and CT depicted heterogeneous expansile lesions with centrally hypodense areas and peripheral sclerosis. All cases involved extra-osseous extension, producing a mass effect on adjacent soft tissues and nerve roots. On MRI, the neoplasms displayed iso- to- slightly- low signal intensity on T1-weighted images and hyperintense signal intensity on T2-weighted images with heterogeneous enhancement. The literature review resulted in 102 IOS cases, which to the best of our knowledge, is the largest review on IOS, and the imaging findings of the previously published cases were the same as our cases. IOSs are rare benign neoplasms that should be considered in the differential diagnosis of well-defined expansile lytic lesions with sclerotic borders. This is particularly important in middle-aged adults with mandibular, sacral, or vertebral body mass.

Burden of knee osteoarthritis in the Middle East and North Africa (MENA): an epidemiological analysis from 1990 to 2019.

BACKGROUND: Knee is the most affected joint in osteoarthritis (OA) and accounts for almost four-fifths of the burden of OA globally. We aimed to explore the prevalence, incidence, trends, and burden of knee OA during 1990-2019 in the Middle East and North Africa (MENA) region, using the Global Burden of Disease (GBD) study data. METHODS: This is an epidemiological study based on the GBD data from 1990 to 2019 on knee OA in MENA countries. The prevalence, incidence, and years lived with disability (YLD) numbers of knee OA were obtained for both genders. Similarly, age-standardized rates of these indexes per 100,000 people and the proportion of total YLD caused by knee OA in each country and for the MENA region were evaluated. RESULTS: The prevalence of knee osteoarthritis in the MENA region increased 2.88-fold, from 6.16 million cases to 17.75 million, between 1990 and 2019. Furthermore, in 2019, knee osteoarthritis accounted for approximately 1.69 million (95% UI 1.46-1.95) incident cases in MENA. The age-standardized prevalence was higher in women between 1990 (3.94% [95% UI 3.39-4.55] in women and 3.24% [95% UI 2.79-3.72] in men) and 2019 (4.44% [95% UI 3.83-5.10] in women and 3.66% [3.14-4.21] in men). Total YLDs due to knee osteoarthritis increased by more than 2.88-fold, rising from 196.29 thousand [95% UI 97.17-399.29] in 1990 to 564.66 thousand [95% UI 275.06-1,150.68] in 2019. In the year 2019, Kuwait, Turkey, and Oman had the highest age-standardized prevalence (4.42% [95% UI 3.79-5.08]), YLD (132.41 [95% UI 65.79-267.56] per 100 000), and increase (21.17%) in YLD compared with 1990 in MENA region, respectively. CONCLUSION: The prevalence of and YLDs due to knee OA in MENA has escalated over the last three decades. Considering the expanding burden of knee OA in MENA, policymakers should be more concerned to implement preventive strategies.

Burden of Hand Osteoarthritis in the Middle East and North Africa (MENA): An Epidemiological Analysis From 1990 to 2019.

PURPOSE: Hand osteoarthritis (OA) is a common cause of disability in older people. Although often underemphasized, it may affect quality of life and imposes a considerable burden on the health system. This study evaluated the epidemiology of hand OA in the Middle East and North Africa (MENA) region. METHODS: This epidemiological study was performed based on the Global Burden of Disease study from 1990 to 2019. The incidence, prevalence, and years lived with disability (YLD) in all 21 MENA countries during the study period were reported in rate, age-standardized, and percentage. RESULTS: Hand osteoarthritis in MENA increased 2.7-fold, from 1.6 million cases to 4.3 million from 1990 to 2019 with an age-standardized incidence rate of 50.2 (95% CI, 38.2-66.4) per 100,000 people in 2019. Saudi Arabia had the highest age-standardized prevalence in both 1990 (2.3%) and 2019 (2.3%), whereas Turkey had the lowest (0.3%) in both years. Total YLDs due to hand osteoarthritis increased by more than 2.7-fold, from 50,335 to 135,336 during the study period. The highest rate of increase in YLD rate from 1990 to 2019 was in Iran (3.3) and the largest decrease was in Qatar (-11.5). CONCLUSIONS: In contrast to the global trend, MENA hand OA prevalence and YLDs did not decrease between 1990 and 2019 and remained constant over time. Aging and increasing obesity rates, particularly among women, might be the contributing factors. Hand OA epidemiology varies by country, possibly due to genetic, ethnic, and environmental factors. TYPE OF STUDY/LEVEL OF EVIDENCE: Prognostic II.

Trait anger representation in microstructural white matter tracts: A diffusion MRI study.

BACKGROUND: Understanding the microstructure of the brain that underlies emotions is of pivotal importance for psychology and psychiatry. Herein, we investigated white matter (WM) tracts associated with anger using the diffusion magnetic resonance imaging (DMRI) connectometry approach while exploring potential sex differences. METHODS: 225 healthy participants from the LEMON database were evaluated using the State-Trait Anger Expression Inventory (STAXI). WM images were prepared and analyzed with DMRI. Multiple regression models were fitted to address the correlation of local connectomes with STAXI components with age and handedness as covariates. RESULTS: There were no statistically significant differences in state anger and trait anger between males and females (p = 0.55 and 0.30, respectively). DMRI connectometry revealed that quantitative anisotropy (QA) values in the bilateral corticospinal tract (CST), splenium of corpus callosum (SCC), middle cerebellar peduncle, left inferior cerebellar peduncle, left cingulum, and left fornix were negatively correlated with trait anger and trait anger temperament (TAT) in males. In contrast, the QA values in the bilateral CST and SCC showed a positive correlation with trait anger and TAT in females, which, however, did not reach statistical significance. LIMITATIONS: The cross-sectional design and self-reported measures of anger limit the generalizability of our results. CONCLUSIONS: This is the first DMRI connectometry study to investigate WM circuits involved in anger. We found that the pathways associated with the limbic system and movement-related regions were involved in trait anger and anger expression in men, while no brain pathways showed a significant relationship with anger in women.

Imaging Tendon Disorders in Athletes.

Imaging plays a critical role in evaluating pathology affecting athletes from various fields. Tendon pathology manifests in terms of mechanical, degenerative, enthesitis, neoplastic, and overuse diseases. Tendon pathologies in athletes usually involve injuries to commonly injured tendons such as the tendons involving the ankle, elbow, rotator cuff, hip abductors, patellar tendon, and Achilles tendon. For the purposes of this article, the focus will be on the tendons involving the ankle such as the tibialis posterior and peroneal tendons. The 2 most common imaging modalities used for the evaluation of tendons are ultrasound (US) and magnetic resonance imaging (MRI). There are several emerging imaging techniques such as T2 mapping, ultra-short echo time MRI, and sonoelastography. These novel imaging techniques are all in research phase and have not been adapted to routine clinical practice.

Brain pathway differences between Parkinson's disease patients with and without REM sleep behavior disorder.

PURPOSE: REM (rapid eye movement) sleep behavior disorder (RBD) is characterized by increased muscle tone and violent limb movements and is a usual symptom of the early stages of Parkinson's disease (PD). PD patients with RBD represent faster motor and cognitive dysfunction progression. However, there are limited studies on possible structural brain changes underpinning this disorder. METHODS: Diffusion magnetic resonance imaging (DMRI) was used to assess whether microstructural abnormalities in the brain of 23 RBD positive PD are detectable compared to 31 RBD negative PD. DMRI scans were analyzed without a prior hypothesis. Diffusion MRI connectometry was used to carry out group analysis between age and gender matched PD patients with and without RBD. Diffusion MRI connectometry is based on spin distribution function (SDF) which quantifies the density of diffusing water and is more sensitive to psychological differences between groups. RESULTS: Patients with RBD positive showed microstructural white matter changes in the left and right cingulum, inferior front occipital fasciculus (IFOF), bilateral corticospinal tracts (CST), and middle cerebellar peduncles (MCPs), compared to patients without RBD. CONCLUSIONS: White matter alterations in the cingulum, IFOF regions, and corpus callosum might explain faster cognitive deterioration in PD patients with RBD, in terms of visual recognition and visuospatial dysfunction and executive function. Disturbed brain structural tissue markers in CST in PD + RBD patients, could be justified in the light of faster motor progression in these patients.