Characteristic Imaging Features Research Articles

Pathophysiological insight into transient global amnesia from quantitative electroencephalography

Transient global amnesia (TGA) is recognized as a benign memory disorder, with characteristic clinical and imaging features. However, the pathophysiology of TGA remains elusive. This study aims to elucidate the pathophysiological changes underlying TGA by exploring the brain activities. In total, 215 patients with TGA (age: 61.8 ± 7.8 years; women: 146) with MRI (within 7 days) and EEG studies (within 90 days) were recruited. Quantitative EEG (QEEG) power spectra and network analysis were performed by the artificial intelligence EEG analysis platform (iSyncBrain®). Subgroup analyses were conducted for different clinical groups, based on symptom duration, EEG timing after onset, and cytotoxic lesions on the MRI. Compared with 252 age- and sex-matched subjects (age: 64.5 ± 8.3 years, women: 182), TGA patients showed a global decrease in absolute power in all band waves, a relative decrease in alpha waves, a relative increase in theta waves, and atypical compensation activity. These QEEG changes were observed regardless of having cytotoxic lesions in MRI and they were significant up to 1 week after symptom onset. Network analysis showed that TGA was more activated than normal controls in alpha1 band-waves, exhibiting a compensatory process. TGA results in prolonged and widespread alterations of brain activity and connectivity. QEEG provide insight into pathophysiology of TGA.

Pancreaticoduodenal Groove: Spectrum of Disease and Imaging Features.

The pancreaticoduodenal groove (PDG) is a small space between the pancreatic head and duodenum where vital interactions between multiple organs and physiologic processes take place. Muscles, nerves, and hormones perform a coordinated dance, allowing bile and pancreatic enzymes to aid in digestion and absorption of critical nutrition. Given the multitude of organs and cells working together, a variety of benign and malignant entities can arise in or adjacent to this space. Management of lesions in this region is also complex and can involve observation, endoscopic resection, or challenging surgeries such as the Whipple procedure. The radiologist plays an important role in evaluation of abnormalities involving the PDG. While CT is usually the first-line examination for evaluation of this complex region, MRI offers complementary information. Although features of abnormalities involving the PDG can often overlap, understanding the characteristic imaging and pathologic features generally allows categorization of disease entities based on the suspected organ of origin and the presence of ancillary features. The goal of the authors is to provide radiologists with a conceptual approach to entities implicating the PDG to increase the accuracy of diagnosis and assist in appropriate management or presurgical planning. They briefly discuss the anatomy of the PDG, followed by a more in-depth presentation of the features of disease categories. A table summarizing the entities that occur in this region by underlying cause and anatomic location is provided. ©RSNA, 2022.

Pathologic Conditions at Imaging of the Spermatic Cord

A wide range of benign and malignant processes can affect the spermatic cord (SC). Familiarity with and recognition of the characteristic imaging features of these entities are imperative for accurate diagnosis and optimal clinical care. While some SC diseases are self-limiting, others can result in infertility and potentially life-threatening infection or bleeding if they are left untreated. Therefore, correct diagnosis is important for life-saving treatment and preservation of fertility. Disorders including anomalies of the vas deferens and the processus vaginalis, arterial and venous diseases (torsion of the SC and varicoceles), infection, trauma, and neoplasms are the most pertinent entities with which radiologists should be familiar when assessing the SC. Knowing what to expect in a patient who has undergone SC interventions is imperative. US has a fundamental role in the initial examination of patients who present with symptoms that indicate abnormalities of the SC, such as suspected posttraumatic testicular retraction or SC torsion. Other imaging techniques including abdominal and pelvic MRI and CT have their own importance. For correct interpretation of the findings and to establish an accurate diagnosis, it is crucial to have a thorough knowledge of the anatomy, the utility and limitations of various imaging modalities, optimal imaging and scanning techniques, and the imaging features of various benign and malignant pathologic conditions that can involve the SC. Online supplemental material is available for this article.©RSNA, 2022.

Basic Pancreatic Lesions: Radiologic-pathologic Correlation.

The basic pancreatic lesions include location, size, shape, number, capsule, calcification/calculi, hemorrhage, cystic degeneration, fibrosis, pancreatic duct alterations, and microvessel. One or more basic lesions form a kind of pancreatic disease. As recognizing the characteristic imaging features of pancreatic basic lesions and their relationships with pathology aids in differentiating the variety of pancreatic diseases. The purpose of this study is to review the pathological and imaging features of the basic pancreatic lesions.

Renal mucormycosis presenting during the COVID-19 pandemic: A series of 11 cases from a tertiary care center in India.

Introduction:Renal mucormycosis has been documented to occur even in apparently immunocompetent individuals. Owing to the rarity of this disease, literature on its management is small. We present our experience of diagnosing and managing 11 cases of primary renal mucormycosis who presented during the second wave of the COVID-19 pandemic in India.Methods:We reviewed the records of all patients presenting to our institute with a diagnosis of acute pyelonephritis from March 2021 to September 2021. All patients with a radiological, microbiological, or histopathological diagnosis of renal mucormycosis were included in the analysis and all demographic and clinical details, including a history of COVID-19 disease and its treatment, were noted. All patients were treated by a combination of intravenous antifungal therapy and aggressive surgical debridement including nephrectomy and multivisceral resection as required. Predictors of mortality were evaluated by statistical analysis.Results:A total of 93 patients presented to our hospital with features of acute pyelonephritis of which 11 patients were suspected to have primary renal mucormycosis based on characteristic imaging features and confirmed on microbiological and histopathological examination. Of these, four patients had a history of COVID-19 infection. Only one patient had diabetes mellitus. Ten patients underwent nephrectomy and seven needed resections of surrounding organs. The colon was the most commonly involved organ. Five patients (45.5%) died of progressive sepsis. None of the predictors of mortality that were analyzed showed statistical significance.Conclusion:A high index of suspicion, early cross-sectional imaging, prompt institution of antifungal therapy, and aggressive surgical extirpation are very important for achieving good outcomes in patients of primary renal mucormycosis.

An Eye for Eyes: Pediatric Ophthalmologic Diseases on MRI

The orbit is predisposed to a wide range of possible pathologic processes due to a complex histologic and anatomic composition within a confined space. The clinical presentation of orbital pathology is often nonspecific, particularly in young children, making radiologic evaluation an important step in the diagnosis. Additionally, while suspected ophthalmologic pathology may be the primary purpose for an imaging study, incidental lesions encompassing a broad range of infectious, inflammatory, neoplastic, and congenital processes are not uncommonly encountered and may serve as important clues to alert the radiologist and clinical team to evaluate other associated pathology. High-resolution MR imaging is the examination of choice for detailed evaluation of orbital and ocular soft tissues, and this article will review characteristic MR imaging features and the clinical significance of various ophthalmologic pathologies in the pediatric population, while highlighting pearls essential to making accurate imaging diagnoses.Learning Objective: To recognize the imaging appearance of pediatric orbital disease from major pathologic categories and describe common imaging features

Mesenchymal tumors of the stomach: radiologic and pathologic correlation.

Mesenchymal tumors of the stomach are uncommon, with gastrointestinal stromal tumor (GIST) being the most common among them. Majority of the tumors may arise from cells of Cajal, smooth muscle cells, neural cells, totipotent stem cells, adipocytes or fibroblasts. Imaging plays an important role not only in staging but also in characterizing these tumors. Many of these tumors have characteristic imaging features. GISTs usually present as large cavitating and necrotic tumors with exophytic component. Presence of fat tissue within the tumor suggests a lipoma or a teratoma, early phase hyperenhancement indicates glomus tumor and hemangioma, and delayed contrast enhancement is seen in schwannoma. Their differentiation from epithelial tumors like carcinoma and neuroendocrine tumors is often possible based on the location (mesenchymal tumors are intramural), spread, morphological appearance and enhancement patterns. However, overlapping features exist between these tumors with imaging often being only suggestive. A biopsy is necessary for a definitive diagnosis in many cases.

Recessive cerebellar and afferent ataxias - clinical challenges and future directions.

Cerebellar and afferent ataxias present with a characteristic gait disorder that reflects cerebellar motor dysfunction and sensory loss. These disorders are a diagnostic challenge for clinicians because of the large number of acquired and inherited diseases that cause cerebellar and sensory neuron damage. Among such conditions that are recessively inherited, Friedreich ataxia and RFC1-associated cerebellar ataxia, neuropathy, vestibular areflexia syndrome (CANVAS) include the characteristic clinical, neuropathological and imaging features of ganglionopathies, a distinctive non-length-dependent type of sensory involvement. In this Review, we discuss the typical and atypical phenotypes of Friedreich ataxia and CANVAS, along with the features of other recessive ataxias that present with a ganglionopathy or polyneuropathy, with an emphasis on recently described clinical features, natural history and genotype-phenotype correlations. We review the main developments in understanding the complex pathology that affects the sensory neurons and cerebellum, which seem to be most vulnerable to disorders that affect mitochondrial function and DNA repair mechanisms. Finally, we discuss disease-modifying therapeutic advances in Friedreich ataxia, highlighting the most promising candidate molecules and lessons learned from previous clinical trials.

Characteristics of Retained Foreign Bodies in the Tongue: A Retrospective Study of 35 Cases

There are only a few case reports of foreign bodies (FBs) in the tongue. Delayed diagnosis or misdiagnosis is commonly reported. The purpose of this study was to identify the demographic, clinical, and radiological features that might facilitate the diagnosis of retained FBs in the tongue. A retrospective case series was performed. Clinical and imaging data of patients with FBs in the tongue at Wuhan University Hospital of Stomatology were reviewed. The outcome variable was a preliminary, radiological, intraoperative, or pathological diagnosis. Covariates included age, sex, FB-related history, symptoms and signs, duration, and computed tomography (CT) imaging features. Descriptive statistics were computed for each study variable. Thirty-five patients were included. The sample's mean age was 54.5±11.2years, included 19 males (54.3%). Eighty percent of the patients reported FB-related history with a mean duration of 4weeks. More than 70% of the patients presented with tongue swelling. Approximately half of the 35 cases were preliminarily misdiagnosed, and 15 of them were initially suspected to be tumors. After CT examinations, 33 of the 35 cases were diagnosed as FB. Characteristic CT imaging feature of the FB was a radiopaque line. Most FBs were located at the anterior two-thirds and marginal area of the tongue and in an oblique direction. The depth of FB was 0.61±0.42cm. The superficial ends of most FBs were close to the surface of the dorsum and the tongue margin. The possibility of a retained FB should be included in the differential diagnosis of a nonhealing wound or tongue enlargement when a radiopaque line is present on CT images of patients presenting with or without FB-related history. It may be easier to detect a FB in the tongue when a CT imaging postprocessing protocol, including thin-slice reconstruction and multiplanar reformation visualization and careful interpretation, is used.

Imaging of the mediastinum: Mimics of malignancy.

In the imaging of the mediastinum, benign lesions mimicking malignancy constitute potential pitfalls in interpretation. Localization and characteristic imaging features are key to narrow the differential diagnosis and avoid potential pitfalls in interpretation. Based on certain anatomic landmarks, the mediastinal compartment model enables accurate localization. Depending on the anatomic origin, mediastinal lesions can have various etiologies. The anatomic location and structures contained within each mediastinal compartment are helpful in generating the differential diagnoses. These structures include thyroid, thymus, parathyroid, lymph nodes, pericardium, embryogenic remnants, and parts of the enteric tracts, vessels, and nerves. Imaging characteristics on computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography-computed tomography (PET/CT), including attenuation (fluid, fat, calcification), contrast enhancement, and metabolic activity, aid in narrowing the differential diagnoses. Understanding the roles and limitations of various imaging modalities is helpful in the evaluation of mediastinal masses. In this review, we present potential pitfalls in the imaging of mediastinal lesions with emphasis on the mimics of malignancy.

Spectrum of Ovarian Incidentalomas: Diagnosis and Management.

Incidental ovarian lesions are asymptomatic lesions that are accidentally discovered during a CT or MRI examinations that involves the pelvic cavity or during a routine obstetric ultrasound study. Incidental ovarian masses are usually benign with a very low risk of malignancy yet underlying malignant pathology may be discovered during the diagnostic work-up of these lesions. Suspicion of malignancy is directly correlating with the increase in the patient's age, the increase in the size of the lesion, the presence of the solid components or thick septa and a high color scale of the ovarian mass. Following standard reporting and management protocols are essential to choose the proper work-up of these lesions to avoid unnecessary additional imaging and operative intervention. In this article, we will provide a review of the characteristic imaging features of some incidental and yet commonly encountered ovarian lesions. We will also summarize the recently published algorithms that are important for consistent reporting and standard management of these lesions.

The application research of AI image recognition and processing technology in the early diagnosis of the COVID-19

BackgroundThis study intends to establish a combined prediction model that integrates the clinical symptoms,the lung lesion volume, and the radiomics features of patients with COVID-19, resulting in a new model to predict the severity of COVID-19.MethodsThe clinical data of 386 patients with COVID-19 at several hospitals, as well as images of certain patients during their hospitalization, were collected retrospectively to create a database of patients with COVID-19 pneumonia. The contour of lungs and lesion locations may be retrieved from CT scans using a CT-image-based quantitative discrimination and trend analysis method for COVID-19 and the Mask R-CNN deep neural network model to create 3D data of lung lesions. The quantitative COVID-19 factors were then determined, on which the diagnosis of the development of the patients' symptoms could be established. Then, using an artificial neural network, a prediction model of the severity of COVID-19 was constructed by combining characteristic imaging features on CT slices with clinical factors. ANN neural network was used for training, and tenfold cross-validation was used to verify the prediction model. The diagnostic performance of this model is verified by the receiver operating characteristic (ROC) curve.ResultsCT radiomics features extraction and analysis based on a deep neural network can detect COVID-19 patients with an 86% sensitivity and an 85% specificity. According to the ROC curve, the constructed severity prediction model indicates that the AUC of patients with severe COVID-19 is 0.761, with sensitivity and specificity of 79.1% and 73.1%, respectively.ConclusionsThe combined prediction model for severe COVID-19 pneumonia, which is based on deep learning and integrates clinical aspects, pulmonary lesion volume, and radiomics features of patients, has a remarkable differential ability for predicting the course of disease in COVID-19 patients. This may assist in the early prevention of severe COVID-19 symptoms.

A Review of Posteromedial Lesions of the Chest Wall: What Should a Chest Radiologist Know?

A heterogeneous group of tumors can affect the posteromedial chest wall. They form diverse groups of benign and malignant (primary or secondary) pathologies that can arise from different chest wall structures, i.e., fat, muscular, vascular, osseous, or neurogenic tissues. Chest radiography is very nonspecific for the characterization of chest wall lesions. The modality of choice for the initial assessment of the chest wall lesions is computed tomography (CT). More advanced cross-sectional modalities such as magnetic resonance imaging (MRI) and positron emission tomography (PET) with fluorodeoxyglucose are usually used for further characterization, staging, treatment response, and assessment of recurrence. A systematic approach based on age, clinical history, and radiologic findings is required for correct diagnosis. It is essential for radiologists to be familiar with the spectrum of lesions that might affect the posteromedial chest wall and their characteristic imaging features. Although the imaging findings of these tumors can be nonspecific, cross-sectional imaging helps to limit the differential diagnosis and determine the further diagnostic investigation (e.g., image-guided biopsy). Specific imaging findings, e.g., location, mineralization, enhancement pattern, and local invasion, occasionally allow a particular diagnosis. This article reviews the posteromedial chest wall anatomy and different pathologies. We provide a combination of location and imaging features of each pathology. We will also explore the role of imaging and its strengths and limitations for diagnosing posteromedial chest wall lesions.

Benign-appearing Incidental Adnexal Cysts at US, CT, and MRI: Putting the ACR, O-RADS, and SRU Guidelines All Together

Adnexal cysts are a common incidental finding at US, CT, and MRI but have historically caused a diagnostic dilemma for determining when to follow up and how to manage them. Characteristic imaging features of simple adnexal cysts include a simple fluid collection with smooth walls and no solid or vascular components. Day-to-day practice guidelines were recently updated to reflect the overwhelming evidence that incidental cystic adnexal masses are almost always benign. Three major consensus articles on adnexal cystic masses were published between 2019 and 2020: the Society of Radiologists in Ultrasound (SRU) consensus update on adnexal cysts, the Ovarian-Adnexal Reporting and Data System (O-RADS) US consensus guideline, and the American College of Radiology (ACR) white paper on the management for incidental adnexal findings at CT and MRI. All three standardize reporting terminology, are based on evidence-based data and institutional practice patterns, and apply to nonpregnant women of average risk for ovarian cancer. While there are small differences in follow-up recommendations based on size thresholds, the goal of each is the same-to limit unnecessary imaging follow-up and, by doing so, save the patient time, money, and anxiety. For the diagnostic radiologist to use these guidelines, it is essential that the entire mass is visualized well. Without adequate visualization, further characterization of the mass may be necessary. To put it all together, the SRU consensus guideline and ACR white paper are easily applied in day-to-day practice for masses that are O-RADS 2 and below. An invited commentary by Patel is available online.The online slide presentation from the RSNA Annual Meeting is available for this article.©RSNA, 2022.

Lower motor neuron involvement in patients with neuromyelitis optica spectrum disorders

BackgroundInvolvement of the central gray matter of spinal cord is a characteristic magnetic resonance imaging (MRI) feature of aquaporin-4-immunoglobulin G antibodies (AQP4-IgG) positive neuromyelitis optica spectrum disorders (NMOSD). However, there has been no systemic electrophysiological study investigating the frequency of lower motor neuron involvement in NMOSD patients. MethodsWe retrospectively reviewed a cohort of 59 NMOSD patients with results of concentric needle electromyography (EMG) and nerve conduction studies (NCS) that were admitted to the Department of Neurology of Chinese PLA General Hospital between January 2016 and December 2019. ResultsAcute and/or chronic denervation was found in 22.0% (13/59) of the NMOSD patients by EMG. Peripheral or cranial neuropathy indicated by abnormal NCS changes was found in 11.9% (7/59) of the NMOSD patients. Denervation indicated by EMG that can be accounted for by abnormal NCS was found in 6.8% (4/59) of the NMOSD patients, while 3.4% (2/59) of the NMOSD patients had NCS abnormality without denervation indicated by EMG. Accordingly, 9 of the 59 NMOSD patients (15.3%) had lower motor neuron involvement, and moreover, 6.8% (4/59) of the NMOSD patients had corresponding spinal cord or brainstem lesions on MRI. ConclusionNot uncommon lower motor neuron involvement exists in NMOSD patients, so needle EMG and NCS studies should be performed in NMOSD patients with suspected lower motor neuron involvement.

Imaging thumbprint of molecular subtypes of breast cancer

Breast cancers have traditionally been classified based on histology. However, with the development in imaging modalities and available treatment options, it is imperative to also focus on the molecular classes of breast cancer. Molecular profile and gene expression are important predictors of treatment response and overall prognosis. Radiologists should have a good understanding of molecular categories of breast cancer along with their imaging hallmarks. Highlights: • To familiarize the readers with the principal biomarkers and molecular classes of breast cancer. • To highlight the characteristic imaging features of each molecular class of breast cancer. • To focus on the pivotal role of molecular classification in the dynamic model of breast cancer treatment.

Lessons learned from a fatal case of tuberculous meningitis with a rapid decline in an infant.

Tuberculous meningitis is a highly lethal, often underrecognized disease with characteristic clinical and imaging features which can be cured if the diagnosis and subsequent treatment are begun at early stages. Frequently, there is a delayed diagnosis of this condition due to unfamiliarity of clinicians in non-endemic areas about its presentation and diagnostic workup. This article presents a case of rapid decline and fatality due to tuberculous meningitis in an 11-month-old child from a non-TB-endemic area and describes the characteristic clinical presentation, imaging findings, and diagnostic pitfalls associated with this condition.

MDCT Evaluation of Celiac Axis Compression SyndromeA Rare Case Series

Celiac axis compression syndrome is an uncommon entity of abdominal vascular compression syndrome which results from the compression of the proximal celiac artery by the hypertrophied median arcuate ligament. The patients present clinically with postprandial abdominal pain predominantly in the epigastric region and weight loss. The use of thin-section Multidetector Computed Tomography (MDCT) and 3-Dimensional (3D) image reconstruction has greatly improved the ability to obtain detailed images and helped to assess the abdominal vascular system non invasively. Five cases of celiac axis compression syndrome with its characteristic MDCT imaging features like hooked appearance, thickened median arcuate ligament more than 4 mm, poststenotic dilatation and posterior and inferior displacement of celiac artery with indentation on aorta have been described in the present case series and the imaging findings described by other authors in their reported studies have also been compared.

Dandy–Walker Malformation Presenting with Hearing Loss

Dandy–Walker malformation (DWM) is a common congenital posterior fossa anomaly, however, its association with concomitant bilateral inner ear anomalies has been rarely reported so far. We present such a case that showed characteristic imaging features of DWM along with uncommon vestibulocochlear anomalies like cochlear hypoplasia and Internal Auditory Canal atresia.

Ultrasound and Computed Tomography Features of Non Cirrhotic Portal Hypertension caused due to Non Cirrhotic Portal Fibrosis and Extrahepatic Portal Vein Obstruction: A Retrospective Study

Introduction: Non Cirrhotic Portal Hypertension (NCPH) encompasses a wide range of disorders that are characterised by increased portal pressure with the absence of cirrhosis of liver. The disorders are classified anatomically based on the site of blood flow obstruction into prehepatic, hepatic and posthepatic causes. These numerous and variable aetiological factors and the lack of standardised diagnostic criteria, makes NCPH under-recognised both clinically and pathologically and often being falsely labelled as cryptogenic cirrhosis. Therefore, it is important for radiologists to be aware of the imaging features that constitute NCPH for its early recognition, so that appropriate management can be carried out. Aim: To assess the distinct ultrasound and Computed Tomography (CT) features of the two main causes of NCPH: Non Cirrhotic Portal Fibrosis (NCPF) and Extrahepatic Portal Venous Obstruction (EHPVO). Materials and Methods: This retrospective observational study included all radiologically diagnosed cases of NCPH who underwent ultrasound and CT examination at the Institution between June 2020-June 2021. A total of 10 patients met the inclusion criteria. The various imaging features of NCPF and EHPVO were analysed and tabulated. Results: The study showed male predominance with males and females being seven and three, respectively. The mean age of the patients in the study was 35.1 years. The common cause in both NCPF and EHPVO was idiopathic. The most characteristic imaging finding in EHPVO was cavernous transformation of the portal vein seen in all cases and that in NCPF being dilatation of the spleno-portal axis and mural thickening of the main portal vein seen in all the cases. Conclusion: The present study demonstrated the characteristic imaging features of NCPF and EHPVO which are leading cause of NCPH, facilitating radiologist to identify the conditions and not label cases with Portal Hypertension (PHT) as cryptogenic cirrhosis.