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.
CT scoring criteria were applied to images from sequential chest CT examinations. A, Initial chest CT image obtained 2 days after onset of symptoms shows small region of subpleural ground-glass opacities in right lower lobe, for CT score of 1. B, Chest CT image obtained on day 3 of treatment shows slightly enlarged region of subpleural ground-glass opacities with partial crazy-paving pattern and consolidation, for CT score of 3. C, Chest CT image obtained on day 5 of treatment shows partial resolution of consolidation, for CT score of 2. D, Chest CT image obtained on day 14 of treatment shows continued resolution of consolidation with minimal residual ground-glass opacities, for CT score of 1. Image courtesy of American Journal of Roentgenology (AJR)
Fig 1. A sample scoring on CT images of a 63-year-old woman from mortality group demonstrated a total score of 63. It was calculated as: for upper zone (A), 3 (consolidation) × 3 (50–75% distribution) × 2 (both right and left lungs) + 2 (ground glass opacity) ×1 (< 25% distribution) × 2 (both right and left lungs); for middle zone (B), 3 (consolidation) × 2 (25–50% distribution) × 2 (both right and left lungs) + 2 (ground glass opacity) × 2 (25–50% distribution) × 2 (both right and left lungs); for lower zone (C), 3 (consolidation) × (2 (25–50% distribution of the right lung) + 3 (50–75% distribution of the left lung)) + 2 (ground glass opacity) × (2 (25–50% distribution of the right lung) + 1 (< 25% distribution of the left lung)) Yuan et al, 2020 (CC BY 4.0)
A, Image from noncontrast head CT demonstrates symmetric hypoattenuation within the bilateral medial thalami (arrows). B, Axial CT venogram demonstrates patency of the cerebral venous vasculature, including the internal cerebral veins (arrows). C, Coronal reformat of aCT angiogram demonstrates normal appearance of the basilar artery and proximal posterior cerebral arteries. Image courtesy of the Radiological Society of North America (RSNA)
Typical CT imaging features for COVID-19. Unenhanced, thin-section axial images of the lungs in a 52-year-old man with a positive RT-PCR (A-D) show bilateral, multifocal rounded (asterisks) and peripheral GGO (arrows) with superimposed interlobular septal thickening and visible intralobular lines (“crazy-paving”). Routine screening CT for diagnosis or exclusion of COVID-19 is currently not recommended by most professional organizations or the US Centers for Disease Control and Prevention. Image courtesy of RSNA
Series CT scans in 35-year-old woman with COVID-19 pneumonia. (a) Scan obtained on illness days 1 showed multiple pure ground-glass opacity (GGO) mainly in right lower lobe. (b) Scan obtained on illness days 5 showed increased extent of GGO and early consolidation. (c) Scan obtained on illness days 11 showed multiple consolidation with almost the same extent. (d) Scan obtained on illness days 15 showed a mixed pattern with a slightly smaller extent, and the perilobular consolidation might suggest the presence of organizing pneumonia. The patient was discharged on illness days 17. Image courtesy of the journal Radiology
Two examples of CT myocardial perfusion (CTP) imaging assessment software. Canon is on the left and GE Healthcare is on the right. Both of these technologies have been around for a few years, but there have been an increasing amount of clinical data from studies showing the accuracy of the technology compared to nuclear imaging, the current stand of care for myocardial perfusion imaging, and cardiac MRI.