Daniele Marin MD, Presenter: Fellowship funded, Bracco Group

Rendon C. Nelson MD, Abstract Co-Author: Consultant, General Electric Company Research support, Bracco Group Research support, Covidien AG Speakers Bureau, Siemens AG

Antonino Gianluca Guerrisi MD, Abstract Co-Author: Nothing to Disclose

Carlo Catalano MD, Abstract Co-Author: Nothing to Disclose

David Delong, Abstract Co-Author: Nothing to Disclose

Sebastian Tobias Schindera MD, Abstract Co-Author: Nothing to Disclose

To prospectively compare the effect of varying the injection rate of a saline chaser on aortic contrast enhancement during multidetector CT (MDCT) of the abdomen.

The study cohort comprised 75 consecutive patients (39 men, 36 women; mean age, 54 years; age range, 37-75 years) who underwent 64-slice MDCT examination (Somatom Sensation 64; Siemens Medical Solutions) of the abdomen for known or suspected malignancy. After enrollment, patients were randomly assigned one of three injection protocols (Protocols A-C) for which 50 mL of saline was injected at 2.0 mL/s, 4.0 mL/s, and 8 mL/s, respectively, after administration of 150 mL nonionic contrast medium (Iomeron 300; Bracco Diagnostics) at a rate of 4.0 mL/s. Low-dose (20 mA, 120 kVp), single-level dynamic acquisitions of the abdominal aorta at the level of the celiac axis were obtained every three seconds from the start of contrast media injection for 60 seconds. Standard CT scanning of the abdomen was then acquired with a constant 75 seconds delay. Aortic time-enhancement curves were plotted to assess peak enhancement, time-to-peak enhancement, and duration of 90% peak enhancement. Data were analyzed with a two-way analysis of variance (P < 0.05).

Injecting the saline chaser at twice the rate or at the same rate (Protocol B, and C, respectively) as the contrast medium yielded significantly higher peak aortic enhancement and shorter time-to-peak enhancement values than injecting the saline at half the rate (Protocol A) as the contrast medium (P 0.05). Average peak aortic enhancement (HU) measured 319 ± 43, 359 ± 47, and 370 ± 60 for Protocol A, B, and C, and occurred at 36 s, 39 s, and 39 s, respectively, after contrast medium injection.

Injecting the saline chaser at twice the rate or at the same rate as the contrast medium significantly increased peak aortic enhancement and time-to-peak enhancement at MDCT of the abdomen.

Increasing the injection rate of the saline chaser can result in an arterial enhancement profile that is better suited to the speed of MDCT during CT angiography.

Marin, D, Nelson, R, Guerrisi, A, Catalano, C, Delong, D, Schindera, S, Dynamic Contrast Enhancement of the Aorta during 64-Slice Multidetector CT of the Abdomen: Effect of Varying Injection Rates of a Saline Chaser.  Radiological Society of North America 2008 Scientific Assembly and Annual Meeting, February 18 - February 20, 2008 ,Chicago IL. http://archive.rsna.org/2008/6017634.html