Algorithm-based approach to focal liver lesions in contrast-enhanced ultrasound.

Focal liver lesions are commonly encountered. Grey-scale and Doppler sonographic characteristics of focal liver lesions are often non-specific and insufficient to conclusively characterise lesions as benign or malignant. Contrast-enhanced ultrasound is useful for the characterisation of FLLs in patients who are unable to undergo contrast-enhanced computed tomography or magnetic resonance imaging. It is also easily available and relatively cheap. However, interpretation of contrast-enhanced ultrasound can be challenging without a systematic approach. In this pictorial essay, we highlight an algorithm-based approach to FLLs and discuss the characteristic contrast-enhanced ultrasound features of commonly encountered and clinically significant focal liver lesions.

Adaptability and responsiveness: keys to operational measures in a regional hospital radiology department during the current COVID-19 pandemic.

The rapid and mostly uncontrolled spread of the coronavirus disease 2019 pandemic over the past 4 months has overwhelmed many healthcare systems worldwide. In Singapore, while our public healthcare institutions were considered well prepared due to our prior experience with the SARS outbreak, there was an unexpected surge of infected patients over the recent 2 months to deal with. We describe our radiology department's experience in modifying operational practices and implementing strict infection control measures aimed at minimizing disease transmission and mitigating the potential impact of possible staff infection. From the perspective of serving a medium-sized regional hospital and limited by physical and manpower constraints, our radiology department had to adapt quickly and modify our initial responses and practices as the disease scenario changed. We have also enumerated some guidelines for planning future radiology departments.

Clinics in diagnostic imaging (203). Focal infarction of the falciform ligament fatty appendage.

A 56-year-old man presented to the emergency department with acute upper abdominal pain and mild leucocytosis. The pain was not relieved by intravenous analgesia. Computed tomography of the abdomen and pelvis demonstrated a focal area of fat stranding with a thin peripheral rim of high attenuation and a punctate central hyperdense dot in the vicinity of the falciform ligament. The diagnosis of focal infarction of the falciform ligament fatty appendage was made based on the imaging findings. The patient responded well to conservative management and was discharged for outpatient follow-up. Focal infarction of the falciform ligament fatty appendage is extremely rare and can mimic various causes of acute abdomen that require emergency surgery. Hence, correct radiological diagnosis is essential to avoid unnecessary surgical intervention. We herein discuss the similarities and differences with other common companion cases such as epiploic appendagitis and omental infarction.

Sonographic assessment of musculoskeletal causes of calf pain and swelling.

Calf pain or swelling is a common presentation to the emergency department. The differential diagnoses are wide. Deep vein thrombosis (DVT) is often the first diagnosis to be excluded given its potentially fatal complications. Musculoskeletal causes of calf pain or swelling such as Baker's cyst, muscle or tendon tear, soft tissue infection, and inflammation are not uncommon and can often be confidently diagnosed with ultrasonography (US). Familiarity with these conditions and the sonographic findings would be useful in making timely and correct diagnosis.

Computer Vision Syndrome: Darkness Under the Shadow of Light.

Radiologists typically spend long hours staring at the computer monitor. This unavoidable nature of our work can lead to detrimental effects on the eyes. Moreover, there is little awareness among radiologists with regards to such potential harm. Ocular hazards, such as computer vision syndrome, are increasingly becoming more relevant to the radiology community. In this article, we discuss the ocular occupational hazards faced by radiologists and suggestions that may help in minimizing such hazards.

Clinics in diagnostic imaging (175). Corpus callosum glioblastoma multiforme (GBM): butterfly glioma.

A 54-year-old man presented with change in behaviour, nocturnal enuresis, abnormal limb movement and headache of one week's duration. The diagnosis of butterfly glioma (glioblastoma multiforme) was made based on imaging characteristics and was further confirmed by biopsy findings. As the corpus callosum is usually resistant to infiltration by tumours, a mass that involves and crosses the corpus callosum is suggestive of an aggressive neoplasm. Other neoplastic and non-neoplastic conditions that may involve the corpus callosum and mimic a butterfly glioma, as well as associated imaging features, are discussed.

Dual-energy CT applications in salivary gland lesions.

The increasing availability of dual-energy CT (DECT) has set the stage for an exciting era in CT technology. This technique is extensively used throughout the world with numerous centres working on the applications of DECT in various radiology subspeciality areas. DECT provides many advantages over the conventional single-energy scan. Instead of a single set of images, radiologists have access to multiple sets of images from a single acquisition. The DECT workstation enables the reader to generate images, according to the clinical setting, in order to answer a specific clinical question. Radiologists should be aware of the basic concepts of DECT and the usefulness of each image data set. This article aimed to describe the basic principles, techniques and applications of DECT in the imaging of salivary gland lesions. The specific roles of each image data set, in the context of salivary gland lesions, are also discussed.

Clinics in diagnostic imaging (173). Scimitar syndrome with horseshoe lung.

A 56-year-old Chinese man presented with giddiness and vertigo. Subsequent chest radiography showed the classic scimitar sign of an abnormal pulmonary venous return. Further evaluation with non-contrast computed tomography substantiated the finding of a partial anomalous venous drainage pattern and identified an associated rare lung anomaly, horseshoe lung. The imaging findings of scimitar syndrome and its association with horseshoe lung are reviewed.

Systemic-pulmonary artery shunt: A rare cause of false-positive filling defect in the pulmonary arteries.

Computed tomographic (CT) pulmonary angiography is widely used for evaluation of pulmonary embolism. Intraluminal filling defects in the contrast enhanced pulmonary arteries are considered diagnostic of pulmonary emboli. We report a false-positive case where filling defects in the pulmonary artery were due to mixing of blood from a complex shunt or vascular malformation between the systemic arteries and pulmonary artery.

Clinics in diagnostic imaging (166). Nonketotic hyperglycaemic chorea-hemiballismus.

A 68-year-old woman with poorly controlled diabetes mellitus presented to the emergency department with choreoathetoid movements affecting the upper and lower left limbs. Computed tomography of the brain did not show any intracranial abnormalities. However, subsequent magnetic resonance (MR) imaging of the brain revealed an increased T1 signal in the right basal ganglia, raising the suspicion of nonketotic hyperglycaemic chorea-hemiballismus. Management consisted of adjusting her insulin dose to achieve good glycaemic control. The patient subsequently recovered and was discharged after eight days. There are many causes of basal ganglia T1 hyperintensity, including hyperglycaemia in patients with poorly controlled diabetes mellitus. This case emphasises the importance of MR imaging in the early diagnosis of hyperglycaemia as a cause of chorea-hemiballismus, to enable early treatment and a better clinical outcome.

Schematic interpretation of lateral neck radiographs of adults in the emergency department: a pictorial review.

The lateral neck radiograph is widely utilized for the evaluation of common neck conditions in the emergency department. The anatomy of the neck is complex and it can be difficult to differentiate between soft tissue structures on a lateral radiograph. We suggest a schematic pattern of interpreting the lateral neck radiograph with case images of various pathologies that can present in the emergency setting.

Imaging findings of swallowed dentures: a case series.

Dental prosthesis is an uncommon ingested non-food foreign body in adults. Once swallowed, it can lead to serious complications and morbidity. Hence, early localization of the offending foreign body is crucial for timely management. As the dentures are usually made up of non-metallic material and often impacted at or below the level of C7 vertebra, conventional radiograph has limited role in their evaluation. We describe the clinical history and imaging findings of swallowed partial dentures in four patients who presented to the emergency department. The dentures were localized using unenhanced CT of the neck that showed the characteristic mildly hyperdense curvilinear or irregular appearance of the dentures within the upper esophagus. Multiplanar CT reconstructions provide an orientation of the ingested denture within the esophagus, thus guiding the endoscopist.

Imaging of acute cholecystitis and cholecystitis-associated complications in the emergency setting.

Acute cholecystitis is a common cause of right upper quadrant pain in patients presenting at the emergency department. Early diagnosis and recognition of associated complications, though challenging, are essential for timely management. Imaging studies, including ultrasonography, computed tomography and magnetic resonance imaging, are increasingly utilised for the evaluation of suspected cases of cholecystitis. These investigations help in diagnosis, identification of complications and surgical planning. Imaging features of acute cholecystitis have been described in the literature and are variable, depending on the stage of inflammation. This article discusses the spectrum of cholecystitis-associated complications and their imaging manifestations. We also suggest a checklist for the prompt and accurate identification of complications in acute cholecystitis.

Computed Tomography Features of External Auditory Canal Cholesteatoma: A Pictorial Review.

Computed tomography (CT) is widely used for evaluation of patients with otologic conditions. External auditory canal cholesteatoma (EACC), although rare, demonstrates characteristic CT appearance. Moreover, the accurate extent of involvement cannot be accurately assessed clinically. This pictorial review aims to illustrate the spectrum of CT features of EACC and highlight the key features that are useful for making an accurate diagnosis of this condition. We have also discussed the radiological and clinical differential diagnoses of external auditory canal lesions that can be mistaken for an EACC.

Massive mediastinal teratoma mimicking a pleural effusion on computed tomography.

Mediastinal teratomas have been reported to mimic pleural effusions on chest radiography. Further evaluation of such tumours using computed tomography usually yields diagnostic characteristics that distinguish them from pleural collections. We report a patient with a mediastinal teratoma that mimicked a massive left pleural effusion on chest radiography and computed tomography.

Use of Ga-68 DOTATATE PET/CT to confirm portal vein tumor thrombosis in a patient with pancreatic neuroendocrine tumor.

A 37-year-old man complained of increasing severity and frequency of abdominal pain over a 2-year period. Initial contrast-enhanced computed tomography of the abdomen demonstrated diffuse enlargement of the pancreas associated with a filling defect in the portal vein, splenomegaly with wedge-shaped peripheral splenic hypodensities and multiple hepatic hypodensities. Findings were suggestive of a pancreatic malignancy complicated by hepatic metastases, splenic infarcts, and portal vein thrombosis. We describe the use of gallium-68 DOTA-DPhe1, Tyr3-octreotate positron emission tomography/computed tomography (Ga-68 DOTATATE PET/CT) in confirming the diagnosis of a pancreatic neuroendocrine tumor with portal vein tumor thrombosis.