Objective: To investigate the effect of a new bolus tracking system on interpatient variability of aortic and coronary enhancement compared with the conventional system in 320-detector computed tomographic (CT) coronary angiography (CTCA).
Methods: Sixty-four patients who underwent CTCA were assigned to 1 of 2 protocols. In group A (n = 32), 7 seconds after triggering (150-Hounsfield unit [HU] threshold) in the ascending aorta, a CT scan was performed. In group B (n = 32), 2 thresholds were set in the ascending aorta. After the first triggering (100 HU threshold), the patient was instructed to take a breath and hold it. Approximately 3 seconds after the second triggering (300 HU threshold), a CT scan was started automatically.
Results: There were no significant differences in the mean CT attenuation for the ascending aorta between the 2 groups (P = 0.61), whereas the standard deviation of the CT attenuation in group B was significantly smaller than that in group A (P = 0.02).
Conclusions: The use of a 2-threshold setting in the new bolus tracking technique could reduce interpatient variability more than a protocol using a single threshold in CTCA.
From the *Department of Diagnostic Radiology, Hiroshima University, Hiroshima, Japan; †Department of Radiology, and ‡Internal Medicine III, Osaka Medical College, Takatsuki City, Osaka, Japan.
Received for publication August 11, 2012; accepted October 12, 2012.
Reprints: Fuminari Tatsugami, MD, Department of Diagnostic Radiology, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan (e-mail: email@example.com).
The authors have no funding or conflicts of interest to disclose.