Double ROI Timing Bolus Technique to Perform Aortic CT Angiography With a 9-Second Contrast Injection Duration

Double region of interest timing bolus technique following endovascular aortic repair: Short-term prognosis analysis

“…the aortic arch (Figure 1(a), L0), chest scan length (Figure 1(a), L1), and the abdominal scan length (Figure 1(a), L2) were recorded. 5 A timing bolus scan was performed at the level of the aortic root with a tube voltage of 80 or 100 kVp and a current of 60 or 30 mAs. We used 7 and 9 mL of iopamidol 370 mg iodine/mL (Iopamiron 370; Bayer, Osaka, Japan) and a 30 mL saline flush, with an injection speed of 3.6 and 4.5 mL/s when the tube voltage was 80 and 100 kVp, respectively ( Table 1).…”

“…This amount was determined based on the results of a previous study to achieve a target enhancement of 380 Hounsfield units (HU). 5 The scan start timing was set as T2 and the helical pitch was adjusted to scan the aorta with the following scan time…”

“…where C is a constant to adjust for abdominal stents (C ¼ 1 s) and abdominal aortic aneurysms (C ¼ 1 s for diameter 40-49 mm, C ¼ 2 s for diameter !50 mm). 5 Finally, a delayed phase scan was performed with the same scan parameters of the plain scan. The scan initiated 16 s after the end of the early phase.…”

“…The length of the aortic root to the top of the aortic arch (Figure 1(a), L 0), chest scan length (Figure 1(a), L 1), and the abdominal scan length (Figure 1(a), L 2) were recorded. 5…”

“…3,4 Furthermore, double region of interest (ROI) timing bolus (DRTB) technique reduced the contrast medium for CT angiography of the aorta to 40 mL, while significantly increasing the aortic enhancement than the conventional method. 5 CT of the aorta could be performed with an injection time of 9 s by synchronizing the scan speed to the aortic flow. However, the short injection time might overlook complications after endovascular stent placement such as endoleaks.…”