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

OBJECTIVES: To compare the incidence rate of reintervention in patients with and without complication findings at aortic computed tomography using double region of interest timing bolus (DRTB) method after endovascular stent placement of the aorta. METHODS: We included 40 patients who underwent computed tomography of the aorta using DRTB method after endovascular stent placement. DRTB method allows to scan the aorta with a short injection time of 9 s by synchronizing the scan speed to the aortic flow. Complication findings at computed tomography were defined as endoleak, rupture, occlusion, and infection. The primary endpoint was reintervention, which was defined as any of the following three events: conversion to open repair, graft revision, or secondary intervention. RESULTS: The mean contrast medium during computed tomography angiography was 38.6 ± 3.9 mL. Complication findings at computed tomography were present in 10 patients (25%): endoleak (n = 9) and infection (n = 1). During a median follow-up of 7 months (interquartile range, 4-11 months), two patients experienced reintervention. Kaplan-Meier curves by complication findings showed that event rate at 6 months was significantly higher in patients with complication findings than in patients without (20% vs 0%, p = 0.01). No patients without complication findings at computed tomography experienced reintervention. CONCLUSIONS: No complication findings at computed tomography after intervention of the aorta resulted in good prognosis in patients who underwent aortic computed tomography using DRTB method.

Aortic CT angiography using the double region of interest timing bolus technique: feasibility of 80 kVp scanning in lean patients.

To investigate the feasibility of aortic computed tomography angiography (CTA) performed at 80 kVp in lean patients using the double region of interest timing bolus (DRTB) technique compared to 100 kVp scanning. This study was approved by the institutional ethics committee, and all patients provided written informed consent. We prospectively included 165 patients from July 2018 to February 2019. We used an 80 kVp protocol when the maximal tube current did not exceed the limit using automatic exposure control; otherwise, 100 kVp was selected. The scan parameters for aortic CTA were determined from the test scan data. Enhancement at six points of the aortoiliac arteries and noise at the bifurcation level were measured. We compared the enhancement and signal to noise ratio (SNR) using Student's t-test. The tube voltage was 80 kVp in 87 patients (53%). The enhancement of the aortoiliac arteries was significantly higher (449.3 ± 77.8 vs 378.7 ± 53.1 HU, p < 0.0001) and the SNR was similar (42.4 ± 11.1 vs 40.0 ± 10.6, p = 0.17), and the amount of contrast medium was lower (33.0 ± 2.5 vs 41.8 ± 3.3 ml, p < 0.001) in the 80 kVp group compared to the 100 kVp group. Reducing the tube current to 80 kVp could decrease the amount of contrast medium used compared to the 100 kVp protocol, while maintaining image quality, for aortic CTA using the DRTB technique.

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

OBJECTIVE. The purpose of this study was to investigate the feasibility of a double ROI timing bolus technique for performing aortic CT angiography (CTA) with 40 mL of contrast medium over 9 seconds. SUBJECTS AND METHODS. A prospective study from February to July 2018 included 106 patients with clinical indications for evaluation of aortic aneurysm or dissection or suspected aortic disease. Forty-seven of these patients had undergone prior aortic CTA by the conventional method. The scanning speed for the double ROI timing bolus technique was calculated from the time-attenuation curves of the ascending and descending aorta by use of the timing bolus data to synchronize aortic flow. The conventional scan was obtained by injection of 1.7 mL of contrast medium per kilogram of body weight for 25 seconds. Enhancement of six points on the aortoiliac arteries and superior vena cava was measured. The t test was used to compare the values. RESULTS. Use of the double ROI timing bolus method significantly reduced the amount of contrast medium injected compared with the amount for the conventional method (40.0 mL vs 88.0 ± 9.4 mL, p < 0.001). Use of the method significantly increased aortoiliac enhancement (403.3 ± 76.0 HU vs 359.7 ± 61.5 HU, p < 0.001) and significantly decreased enhancement of the superior vena cava (118.9 ± 46.2 HU vs 239.2 ± 130.5 HU, p < 0.001) compared with the conventional method. In the group with prior CTA images available, the effective dose was significantly lower with the double ROI timing bolus than with the conventional method (8.3 ± 1.7 mSv vs 12.4 ± 3.2 mSv, p < 0.01). CONCLUSION. Use of the double ROI timing bolus method can dramatically reduce the amount of contrast medium used during aortic CTA while improving aortic enhancement and reducing radiation dose.