COVID-19 pneumonia is a newly recognized lung infection. Initially, CT imaging was demonstrated to be one of the most sensitive tests for the detection of infection. Currently, with broader availability of polymerase chain reaction for disease diagnosis, CT is mainly used for the identification of complications and other defined clinical indications in hospitalized patients. Nonetheless, radiologists are interpreting lung imaging in unsuspected patients as well as in suspected patients with imaging obtained to rule out other relevant clinical indications. The knowledge of pathological findings is also crucial for imagers to better interpret various imaging findings. Identification of the imaging findings that are commonly seen with the disease is important to diagnose and suggest confirmatory testing in unsuspected cases. Proper precautionary measures will be important in such unsuspected patients to prevent further spread. In addition to understanding the imaging findings for the diagnosis of the disease, it is important to understand the growing set of tools provided by artificial intelligence. The goal of this review is to highlight common imaging findings using illustrative examples, describe the evolution of disease over time, discuss differences in imaging appearance of adult and pediatric patients and review the available literature on quantitative CT for COVID-19. We briefly address the known pathological findings of the COVID-19 lung disease that may help better understand the imaging appearance, and we provide a demonstration of novel display methodologies and artificial intelligence applications serving to support clinical observations.

The stomach may be involved by a myriad of pathologies ranging from benign aetiologies like inflammation to malignant aetiologies like carcinoma or lymphoma. Multidetector CT (MDCT) of the stomach is the first-line imaging for patients with suspected gastric pathologies. Conventionally, CT imaging had the advantage of simultaneous detection of the mural and extramural disease extent, but advances in MDCT have allowed mucosal assessment by virtual endoscopy (VE). Also, better three-dimensional (3D) post-processing techniques have enabled more robust and accurate pre-operative planning in patients undergoing gastrectomy and even predict the response to surgery for patients undergoing laparoscopic sleeve gastrectomy for weight loss. The ability of CT to obtain stomach volume (for bariatric surgery patients) and 3D VE images depends on various patient and protocol factors that are important for a radiologist to understand. We review the appropriate CT imaging protocol in the patients with suspected gastric pathologies and highlight the imaging pearls of various gastric pathologies on CT and VE. INTRODUCTIONVarious pathologies like gastritis, carcinoma, lymphoma, carcinoid, metastases, bezoar or corrosive injury may affect the stomach. CT is usually the initial imaging investigation of choice for evaluation of these cases. Conventionally, CT could evaluate the mural and extramural extent of diseases and could not provide any mucosal information. Advances in the CT technology and three-dimensional (3D) post-processing software have enabled new exciting possibilities like CT-based endoscopic images [virtual endoscopy (VE)] 1 as well as allowed accurate staging for neoplastic diseases of the stomach 2 and predict the post-operative weight loss for patients undergoing bariatric surgery.3 It is very important for a radiologist to understand the appropriate gastric imaging protocol, since the acquisition of appropriate CT images requires patient fasting, adequate gastric distension and a negative intraluminal contrast agent. This article describes the basic principle and protocol for multidetector CT (MDCT) of the stomach and reviews the role of CT for the diagnosis of various gastric pathologies and post-operative surveillance.

A 61-year-old man presented with left-side neck pain and swelling, dizziness, night sweats, and significant weight loss. His laboratory investigations showed pancytopenia with hemoglobin of 8.6 g/dL, leukocyte count of 600 per mL, and platelet count of 15 000 per mL. Bone marrow aspiration and biopsy revealed 90% blasts (panel A) with a peculiar "cup-shaped" nuclear morphology (panel B). Molecular diagnostics revealed the presence of cooccurring mutations of the nucleophosmin (NPM1) and Fms-like tyrosine kinase (FLT3) genes. Cytogenetic studies did not show any abnormalities. The patient was started on induction chemotherapy with cytarabine and idarubicin and demonstrated good response.

Transcatheter arterial chemoembolization (TACE) is a well-recognized procedure for management of hepatocellular carcinoma. We present a 54-year-old man who presented with a periumbilical maculopapular skin rash that developed after an otherwise uneventful TACE procedure. A retrospective review of imaging was consistent with non-target embolization of the hepatic falciform artery (HFA). He was treated with oral non-steroidal antiinflammatory medication for 3 weeks with improvement, but had slight skin induration and an excoriated papule at 6-month follow-up. Non-target embolization of HFA is very rare, but clinicians and interventionalists should be aware of this complication, especially in patients predisposed to enlargement of HFA.

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