title: Variable-mode helical CT: imaging protocols.
abstract: Helical CT provides a rapidly acquired, accurately registered, two-dimensional data set during the phase of maximum vascular and parenchymal enhancement. The z-axis can be covered by using either a single acquisition, single breath-hold technique or by using multiple helical groups with intergroup delays for the patient's breathing. The latter approach, called variable-mode helical CT, allows large z-axis coverage of more than one anatomic region during injection of a single bolus of contrast material. We discuss helical scanning protocols, both single-acquisition and variable-mode, that we have developed for detection of disease involving major blood vessels (pulmonary arteries and aorta), perivascular tissue planes (neck, thorax, and pelvis), and abdominal viscera (liver, pancreas, and kidneys).
authors.affiliation: Department of Radiology, University of Chicago Hospitals, IL 60037, USA.
authors.forename: M M
authors.initials: MM
authors.lastname: Tomiak
authors.forename: W D
authors.initials: WD
authors.lastname: Foley
authors.forename: D R
authors.initials: DR
authors.lastname: Jacobson
mesh_terms: D006801:Humans; D014057:Tomography, X-Ray Computed / Q000379:methods*