Bolus tracking of a volume of 120 mL provided the most accurate results in dual-phase liver CT.

No abstract

Our goal was to evaluate the influence of the scan parameters on the 3D virtual endoscopy of the larynx and trachea and the clinical assessment. Helical CT (HiSpeed Advantage; GE, Milwaukee, WI, U.S.A.) of a cadaver phantom was performed with increased collimation (1-10 mm) and pitch (0.5-3). Seventy-two patients with complaints of the upper airways were investigated by virtual endoscopy and their results were compared with the findings of regular endoscopy. Best correlation between virtual endoscopy and anatomical findings, diagnostic quality of the axial slices, and useful longitudinal coverage of the examination were obtained with a collimation of 3 mm and a pitch of 1.5. Space-occupying tumors and stenosis were detected correctly, but the mucous membrane could not be visualized. 3D virtual endoscopy proved to be a valuable method for displaying anatomical structures. For an optimal protocol, a collimation of 3 mm with a pitch of 1.5 is recommended.

Fat saturation and use of a high-caloric meal improve the results of MR angiography of hepatic vessels. MR angiography was comparable to DSA for evaluation of the arterial system and was superior for demonstration of the portal vein; therefore, MR angiography could replace intraarterial DSA.

CT in the arterial phase showed an unusual enhancement pattern of liver lesions in HSC. Scanning only in the portalvenous phase implies possible pitfalls, because lesions may be overlooked or undersized. Therefore, biphasic liver CT is considered essential in the diagnosis and follow-up of HSC in clinical practice.