The most common indication for CT scan of the chest is evaluation of pulmonary nodules. The task is difficult because small nodules can look like blood vessels, and in order to differentiate the two, it is necessary to scroll through the images and note that the nodule is discrete, but a vessel is continuous. Previously chest CT scans used 10 mm collimation so little detail was visualized. Collimation is the thickness of the axial image. Overtime the collimation of CT images has decreased, allowing for increased resolution of nodules. Currently 1 mm images to evaluate the lung parenchyma should be the standard of care. One millimeter collimation generates many more images and requires a greater amount of time for careful review (Figs. 5.1 and 5.2).
KeywordsNonsolid nodule Part-solid nodule Fleischner guidelines Hamartoma Diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH) RECIST (Response Evaluation Criteria in Solid Tumors)
- 9.MacMahon H, Naidich DP, Goo JM, Lee KS, Leung ANC, Mayo JR, Mehta AC, Ohno Y, Powell CA, Prokop M, Rubin GD, Schaefer-Prokop CM, Travis WD, Van Schil PE, Bankier AA. Guidelines for management of incidental pulmonary nodules detected on CT images: from the Fleischner society 2017. Radiology. 2017;284(1):228–43.CrossRefPubMedGoogle Scholar