Computed Tomography (CT)
Computed tomography (CT) systems use a series of X-ray images to create an image volume dataset with slices that can be manipulated on any plane using advanced visualization software. The section includes computed tomography scanners, CT contrast agents, CT angiography (CTA and CCTA), CT perfusion, spectral CT (dual-source CT), and iterative reconstruction dose reduction software.
Figure 1: Examples of chest CT images of COVID-19 (+) patients and visualization of features correlated to COVID-19 positivity. For each pair of images, the left image is a CT image showing the segmented lung used as input for the CNN (convolutional neural network algorithm) model trained on CT images only, and the right image shows the heatmap of pixels that the CNN model classified as having SARS-CoV-2 infection (red indicates higher probability). (a) A 51-year-old female with fever and history of exposure to SARS-CoV-2. The CNN model identified abnormal features in the right lower lobe (white color), whereas the two radiologists labeled this CT as negative. (b) A 52-year-old female who had a history of exposure to SARS-CoV-2 and presented with fever and productive cough. Bilateral peripheral ground-glass opacities (arrows) were labeled by the radiologists, and the CNN model predicted positivity based on features in matching areas. (c) A 72-year-old female with exposure history to the animal market in Wuhan presented with fever and productive cough. The segmented CT image shows ground-glass opacity in the anterior aspect of the right lung (arrow), whereas the CNN model labeled this CT as negative. (d) A 59-year-old female with cough and exposure history. The segmented CT image shows no evidence of pneumonia, and the CNN model also labeled this CT as negative.
Axial (A) and coronal (B) CT of the abdomen and pelvis with IV contrast in a 57-year-old man with a high clinical suspicion for bowel ischemia. There was generalized small bowel distension and segmental thickening (arrows), with adjacent mesenteric congestion (thin arrow in B), and a small volume of ascites (* in B). Findings are nonspecific but suggestive of early ischemia or infection. Image courtesy of RSNA
Figure 4 for the study. Images of a 65-year-old man (patient 6). (a) Cardiac MRI perfusion shows perfusion deficit of anterior/anterolateral wall attributed to left anterior descending artery/left circumflex artery (*). (b) CT coronary angiography. (c) Coronary angiography, left anterior oblique projection with caudal angulation. (d) Three-dimensional image fusion helped refine diagnosis: perfusion deficits (*) were most likely caused by narrow first diagonal branch and its first, stented side branch (arrowhead). Retrospectively, denoted lesion could also be found at CT coronary angiography and coronary angiography (arrowheads in b and c, respectively). CT FFR = CT-derived fractional flow reserve, LGE = late gadolinium enhancement. Image courtesy of RSNA, Radiology.
A complex multicompartmental cerebral hemorrhage on a single axial CT image displayed using the annotation tool in a single portal window. Hemorrhage labels (left column) relevant to the image display on the bottom of the image once selected. ASNR = American Society of Neuroradiology RSNA = Radiological Society of North America. Image courtesy of RSNA
According to the 10 authors from multiple institutions across the US who reviewed the most frequently cited studies on the subject: 'Test performance and management issues arise when inappropriate and potentially overreaching conclusions regarding the diagnostic performance of CT for COVID-19 pneumonia are based on low-quality studies with biased cohorts, confounding variables, and faulty design characteristics. Image courtesy of American Journal of Roentgenology (AJR)
U.S. Army Spc. Jonathon Hyde and Spc. Casymn Harrison from the 1434th Engineer Company, Grayling, Mich., Michigan National Guard, prepare patient rooms at TCF Regional Care Center in Detroit in advance of receiving COVID-19 patients, April 9, 2020. The TCF Center in Detroit has been converted into a 970-bed alternative care facility for COVID-19 patients by the Federal Emergency Management Agency, in partnership with the U.S. Army Corps of Engineers and Michigan National Guard. (Photo courtesy of U.S. Air National Guard photo by Master Sgt. Scott Thompson)