Background There is lack of guidance on specific CT protocols for imaging patients with coronavirus disease 2019 (COVID-19) pneumonia. Purpose To assess international variations in CT utilization, protocols, and radiation doses in patients with COVID-19 pneumonia. Materials and Methods In this retrospective data collection study, the International Atomic Energy Agency (IAEA) coordinated a survey between May and July 2020 regarding CT utilization, protocols, and radiation doses from 62 healthcare sites in 34 countries across five continents for CT exams performed in COVID-19 pneumonia. The questionnaire obtained information on local prevalence, method of diagnosis, most frequent imaging, indications for CT, and specific policies on use of CT in COVID-19 pneumonia. Collected data included general information (patient age, weight, clinical indication), CT equipment (CT make and model, year of installation, number of detector rows), scan protocols (body region, scan phases, tube current and potential), and radiation dose descriptors (CT dose index (CTDI vol ) and dose length product (DLP)). Descriptive statistics and generalized estimating equations were performed. Results Data from 782 patients (median age (interquartile range) of 59(15) years) from 54 healthcare sites in 28 countries were evaluated. Less than one-half of the healthcare sites used CT for initial diagnosis of COVID-19 pneumonia and three-fourth used CT for assessing disease severity. CTDI vol varied based on CT vendors (7-11mGy, p<0.001), number of detector-rows (8-9mGy, p<0.001), year of CT installation (7-10mGy, p=0.006), and reconstruction techniques (7-10mGy, p=0.03). Multiphase chest CT exams performed in 20% of sites (11 of 54) were associated with higher DLP compared with single-phase chest CT exams performed in 80% (43 of 54 sites) (p=0.008). Conclusion CT use, scan protocols, and radiation doses in patients with COVID-19 pneumonia showed wide variation across healthcare sites within the same and different countries. Many patients were scanned multiple times and/or with multiphase CT scan protocols. See also the editorial by Lee .

Background. Single coronary artery (SCA) is a rare congenital anomaly in which there is an isolated coronary artery that arises from a single coronary ostium and provides coronary blood supply to the entire myocardium. SCA is classified into different types based on the origin, branching pattern, and course. Although the majority of patients with SCA are asymptomatic, some patients can present with life-threatening symptoms. Aim. To examine the prevalence, anatomical distribution, and outcome of the single coronary artery anomaly detected on coronary computed tomography angiography (CCTA) in a single center in Oman. Methods. Retrospectively, we reviewed 4,445 patients who underwent coronary computed tomography angiography between September 2012 and August 2018 at the National Heart Center, Muscat, Oman. We identified patients with a single coronary artery, and we evaluated the origin, course, and outcome of SCA. Results. We found 12 patients with single coronary artery among 4,445 patients with a mean age of 56.4 years (age range: 34 to 71 years; male : female ratio: 5 : 7). The most common class was RIII-C seen in 4 patients. Other SCA included RII-C, RII-A, and RII-S, two in each class. One patient had RI and one had LII-P. Two patients had coronary artery bypass graft. No major adverse cardiac events were reported over a mean follow-up of 25.3 months. Conclusion. Single coronary artery (SCA) is a rare congenital anomaly classified into different types. In our study, the prevalence of SCA was 0.27% that is higher than the figures from previous reports.

Anomalous origin of the left coronary artery from the pulmonary artery (ALCAPA) is a rare congenital coronary abnormality also known as Bland-White-Garland syndrome. The incidence of ALCAPA is about 1 in every 300,000 live births, and constitutes 0.24% and 0.46% of all congenital cardiac disease. It has a high infant mortality rate reaching up to 90% if left untreated. For many years, the diagnosis of ALCAPA was by angiography or autopsy. However, multislice computed tomography (MSCT) is a non-invasive imaging tool that allows accurate, non-invasive diagnosis of ALCAPA. Here we report a case of ALCAPA in a six-month-old girl who presented with a two-week history of cough, fever, tachypnea, and sweating during feeding. During admission, an echocardiogram was performed that revealed ALCAPA, which was confirmed using CT. We discuss the role of MSCT in its diagnosis.

Amyloidosis is a disorder characterised by the extracellular deposition of amyloid, a fibrillary protein, in various organs such as the lungs. Pulmonary nodular amyloidosis can mimic other lung conditions that present with pulmonary nodules, such as metastasis, sarcoidosis and hyalinising granuloma. We report a 60-year-old man who presented to the Royal Hospital, Muscat, Oman, in 2017 with a history of shortness of breath upon exertion, orthopnoea and bilateral lower limb swelling. A chest X-ray showed bilateral nodular opacities. Enhanced chest computed tomography revealed bilateral pulmonary nodules with a predominantly perilymphatic and subpleural distribution, giving the impression of a neoplastic nodule. A histopathological examination of biopsied lung tissue confirmed a diagnosis of nodular pulmonary amyloidosis.Keywords: Multiple Pulmonary Nodules; Amyloidosis; Computed Tomography; Case Report; Oman.

Localized hepatobiliary tuberculosis (TB) is a rare disorder which can present with an obstructive jaundice mimicking other noninfectious causes such as cholangiocarcinoma. Here, we report a case of porta hepatis tuberculosis in 19-year-old female who presented with an obstructive jaundice, and her computed tomography (CT) of the abdomen revealed a hepatic hilar mass with radiological features mimicking a malignant biliary tumor. We also review the literature related to this disorder.