Jaundice examination is necessary for the evaluation (as opposed to a single-phase postcontrast CT scan), as the morphology alone of a stone or mass on a single-phase postcontrast examination is typically enough to suggest the best diagnosis (ie, it is not necessary to prove enhancement or lack thereof in an area with classic morphologic imaging features suggestive of a stone or, alternatively, a mass). CT can be used to detect partially or completely calcified biliary calculi but is insensitive for detecting bilirubinate or cholesterol calculi [33,38]. Many gallstones are not radiopaque (available estimates in the older radiology literature suggest that up to 80% of gallstones are noncalcified) [27,42]. Older studies comparing older technology CT and US from the 1990s demonstrate that CT has a sensitivity between 39% to 75% for detection of gallstones compared with US [43]. However, isotropic data routinely obtained with current multislice technology can be reconstructed using narrow collimation and smaller reconstruction intervals, which allow for better visualization of the calculi [33,38]. For the accuracy of cirrhosis detection, a study comparing CT, MRI, and US (compared with explant livers resected for hepatocellular carcinoma at the time of transplant), found that CT had an accuracy of 67%, MRI an accuracy of 70.3%, and US an accuracy of 64% [44]. A more recent study from 2016 showed that use of surface nodularity quantification on CT was highly accurate (area under the receiver operating characteristic curve of 0.929) in differentiating cirrhotic from noncirrhotic liver [45]. MRI Abdomen MRI is an advanced noninvasive imaging technique that uses powerful magnets to obtain high-contrast images of the abdomen; it is more time consuming (typically requiring image acquisitions of 30 minutes) than either CT or US but offers improved contrast resolution over CT and US. MRI can accurately demonstrate both the site and cause of biliary obstruction [34,46].
Jaundice. Jaundice examination is necessary for the evaluation (as opposed to a single-phase postcontrast CT scan), as the morphology alone of a stone or mass on a single-phase postcontrast examination is typically enough to suggest the best diagnosis (ie, it is not necessary to prove enhancement or lack thereof in an area with classic morphologic imaging features suggestive of a stone or, alternatively, a mass). CT can be used to detect partially or completely calcified biliary calculi but is insensitive for detecting bilirubinate or cholesterol calculi [33,38]. Many gallstones are not radiopaque (available estimates in the older radiology literature suggest that up to 80% of gallstones are noncalcified) [27,42]. Older studies comparing older technology CT and US from the 1990s demonstrate that CT has a sensitivity between 39% to 75% for detection of gallstones compared with US [43]. However, isotropic data routinely obtained with current multislice technology can be reconstructed using narrow collimation and smaller reconstruction intervals, which allow for better visualization of the calculi [33,38]. For the accuracy of cirrhosis detection, a study comparing CT, MRI, and US (compared with explant livers resected for hepatocellular carcinoma at the time of transplant), found that CT had an accuracy of 67%, MRI an accuracy of 70.3%, and US an accuracy of 64% [44]. A more recent study from 2016 showed that use of surface nodularity quantification on CT was highly accurate (area under the receiver operating characteristic curve of 0.929) in differentiating cirrhotic from noncirrhotic liver [45]. MRI Abdomen MRI is an advanced noninvasive imaging technique that uses powerful magnets to obtain high-contrast images of the abdomen; it is more time consuming (typically requiring image acquisitions of 30 minutes) than either CT or US but offers improved contrast resolution over CT and US. MRI can accurately demonstrate both the site and cause of biliary obstruction [34,46].