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Paradoxical Effect of Cardiac Output on Arterial Enhancement at Computed Tomography

Does Cardiac Output Reduction Simply Result in an Increase in Aortic Peak Enhancement?

Kidoh, Masafumi MD*; Nakaura, Takeshi MD*; Funama, Yoshinori PhD; Shimonobo, Toshiaki RT*; Shirasaka, Takashi RT*; Hatemura, Masahiro RT*; Utsunomiya, Daisuke MD*; Oda, Seitaro MD*; Yuki, Hideaki MD*; Namimoto, Tomohiro MD*; Higaki, Toru PhD; Awai, Kazuo MD; Yamashita, Yasuyuki MD*

Journal of Computer Assisted Tomography: May/June 2017 - Volume 41 - Issue 3 - p 349–353
doi: 10.1097/RCT.0000000000000541
Cardiac Imaging

Objective The aim of this study was to evaluate the effect of cardiac output (CO) on aortic peak enhancement using protocols with different contrast material (CM) injection durations.

Methods We used a flow phantom that simulated the human circulatory system. Contrast material was injected at a rate of 4.0 mL/s for a period of 2.5, 5, 10, 15, or 20 seconds for a CO of 2.8, 4.2, and 5.6 L/min. Single-level serial computed tomography scans of the simulated aorta were acquired after the start of CM delivery, and aortic peak enhancement was recorded under the different injection protocols.

Results Under a long injection duration protocol (20 seconds), a decrease in CO increased aortic peak enhancement proportionally (CO of 2.8 L/min, 420 Hounsfield units [HU]; CO of 4.2 L/min, 365 HU; CO of 5.6 L/min, 291 HU). However, this effect was decreased under shorter injection duration protocols (5, 10, and 15 seconds); under the shortest (2.5-second) injection duration protocol, a decrease in CO resulted in a decrease in aortic peak enhancement (CO of 2.8 L/min, 36 HU; CO of 4.2 L/min, 51 HU; CO of 5.6 L/min, 55 HU).

Conclusions The magnitude of the effect of CO on aortic peak enhancement depends on the CM injection duration.

From the Departments of *Diagnostic Radiology and †Medical Physics, Kumamoto University, Kumamoto; and ‡Department of Diagnostic Radiology, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan.

Received for publication July 15, 2016; accepted August 27, 2016.

Correspondence to: Masafumi Kidoh, MD, Faculty of Life Sciences, Department of Diagnostic Radiology, Kumamoto University, 1-1-1, Honjo, Kumamoto 860-8556, Japan (e-mail:

The authors declare no conflict of interest.

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