title: EFFECTS OF TWO CONTRAST INJECTION PROTOCOLS ON FELINE AORTIC AND HEPATIC ENHANCEMENT USING DYNAMIC COMPUTED TOMOGRAPHY.
abstract: This prospective study compared aortic and hepatic enhancement achieved using a contrast injection protocol with a fixed rate of 5 ml/s vs. that achieved using a protocol with fixed injection duration of 20 s in eight cats. Cats were assigned into two groups (Group 1, rate 5 ml/s; Group 2, duration 20 s). The dose of contrast was the same in both groups (740 mgI/kg). Regions of interest (ROI) were drawn in the aorta and liver for transverse scans acquired at the hepatic hilus. Time to peak aortic enhancement occurred significantly earlier in Group 1 (M = 11s, SD = 1.63) than in Group 2 (M = 25.5 s, SD = 2.51). Peak aortic enhancement was significantly higher in Group 1 (M = 1906.51 HU, SD = 368.64) than in Group 2 (M = 745.08 HU, SD = 201.84). Duration of aortic enhancement equal to or above 300 HU was statistically longer in Group 2 (M = 24.5 s, SD = 8.39) than in Group 1 (M = 10 s, SD = 1.63). There were no significant differences in time to peak liver enhancement, peak liver enhancement, or duration of hepatic arterial phase between groups. Findings supported the hypothesis that longer injection duration results in a broader bolus geometry with a longer time to peak and a lower peak aortic enhancement in cat. This strong influence of injection duration on timing of aortic enhancement may help future users optimize protocols for CT angiography of the aorta and multiphasic evaluation of the liver, pancreas, and small intestine.
authors: Faculty of Veterinary Science, University of Sydney, NSW, 2006, Sydney, Australia.
authors: Mariano
authors: M
authors: Makara
authors: Faculty of Veterinary Science, University of Sydney, NSW, 2006, Sydney, Australia.
authors: Jennifer
authors: J
authors: Chau
authors: Faculty of Veterinary Science, University of Sydney, NSW, 2006, Sydney, Australia.
authors: Evelyn
authors: E
authors: Hall
authors: Faculty of Veterinary Science, University of Sydney, NSW, 2006, Sydney, Australia.
authors: Heide
authors: H
authors: Kloeppel
authors: Faculty of Veterinary Science, University of Sydney, NSW, 2006, Sydney, Australia.
authors: Juan
authors: J
authors: Podadera
authors: Faculty of Veterinary Science, University of Sydney, NSW, 2006, Sydney, Australia.
authors: Vanessa
authors: V
authors: Barrs
mesh_terms: D000792:Angiography / Q000662:veterinary; D000818:Animals; D001027:Aortography / Q000662:veterinary*; D002415:Cats; D003287:Contrast Media / Q000008:administration & dosage*; D005260:Female; D006499:Hepatic Artery / Q000000981:diagnostic imaging; D007275:Injections, Intravenous / Q000662:veterinary; D007421:Intestine, Small / Q000098:blood supply / Q000000981:diagnostic imaging; D007472:Iohexol / Q000008:administration & dosage; D008099:Liver / Q000098:blood supply* / Q000000981:diagnostic imaging; D008297:Male; D010179:Pancreas / Q000098:blood supply / Q000000981:diagnostic imaging; D011446:Prospective Studies; D011897:Random Allocation; D013997:Time Factors; D014057:Tomography, X-Ray Computed / Q000662:veterinary*
chemical_list: D003287:Contrast Media; D007472:Iohexol
keywords: aortic enhancement; fixed-injection-duration; injection-rate