title: Optimization of automatic bolus tracking for timing of the arterial phase of helical liver CT.
abstract: The aim of this study was to optimize bolus tracking for timing of the arterial phase of biphasic helical liver CT and to compare optimized bolus tracking to a standard delay. One hundred fifty patients were examined with six protocols: 5- or 10-s delay after triggering at a threshold of 50 or 75 or 100 HU enhancement in the aorta at the origin of the celiac arteries after injection of 120 ml contrast material at 3 ml/s. Optimal arterial enhancement was defined as 20-30% of hepatic enhancement in portal venous phase. Another 50 patients were examined with the optimized protocol and compared to 50 gender- and age-matched patients who underwent a 25-s standard delay. A 10-s delay after the 75-HU threshold resulted in the most patients with an optimal arterial phase (p < 0.01). Thirty-one of 75 patients examined with this protocol showed optimal early liver enhancement. Bolus tracking compared with standard delay revealed only a trend for a difference (p = 0.07). The outcome of automatic bolus tracking differs depending on the protocol used; however, optimal arterial phase imaging was seen in only 41% of patients, indicating only a trend for superior timing compared with a standard delay.
authors.affiliation: Institut für Röntgendiagnostik, Universität Würzburg, Germany. joern.sandstede@mail
authors.forename: J J
authors.initials: JJ
authors.lastname: Sandstede
authors.forename: A
authors.initials: A
authors.lastname: Tschammler
authors.forename: M
authors.initials: M
authors.lastname: Beer
authors.forename: C
authors.initials: C
authors.lastname: Vogelsang
authors.forename: G
authors.initials: G
authors.lastname: Wittenberg
authors.forename: D
authors.initials: D
authors.lastname: Hahn
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001012:Aorta, Abdominal / Q000000981:diagnostic imaging; D003287:Contrast Media / Q000008:administration & dosage*; D005260:Female; D006801:Humans; D007275:Injections, Intravenous / Q000379:methods; D008099:Liver / Q000098:blood supply* / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D011169:Portal Vein / Q000000981:diagnostic imaging; D012077:Renal Artery / Q000000981:diagnostic imaging; D012189:Retrospective Studies; D013154:Spleen / Q000000981:diagnostic imaging; D013997:Time Factors; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D003287:Contrast Media