Contrast agent

Demographic information of AAA patients was collected in our hospital medical record system. And CTA images of AAA patients at admission were saved in our imaging workstation, and we collected CTA images in digital imaging and communications in medicine (DICOM) format. SOMATOM Definition Flash CT Scanners, and all CTA were derived by contrast injection, with contrast agent (Bayer Health Care Co., Ltd) 90 ml, injection speed 4 ml/s, slice thickness was 0.75 mm. Table 1 shows the demographic information of the patients, including sex, age, blood pressure on admission, and previous medical history.Table 1

Demographic characteristics and clinical characteristics of abdominal aortic aneurysm patients

	Ruptured group	Unruptured group	P value
	N = 13	N = 22
Gender(male/female)	10/3	19/3	0.648
Age(years)	75(78 − 69.5)	71.09 ± 10.38	0.448
Smoking (%)	66.67	68.18	1.000
Drinking (%)	33.33	54.55	0.297
Hypertension (%)	58.33	40.91	0.475
CADa (%)	16.67	27.27	0.681
Diabetes (%)	8.33	9.09	1.000
SBPb (mmHg)	131.77 ± 39.758	136.95 ± 18.290	0.664
DBPc (mmHg)	80.00(87.50 − 63.50)	80.82 ± 11.065	0.511

^aCAD coronary heart disease

^bSBP systolic blood pressure

^cDBP diastolic blood pressure

Image acquisition was performed in accordance with the Society of Cardiovascular Computed Tomography guidelines.²³ (link) If needed, β-blockers were administered to target a heart rate of 60 beats/min. CT was performed using a 256-section CT scanner (Brilliance iCT; Philips Healthcare). Noncontrast prospective electrocardiographically triggered CT was performed to evaluate coronary calcium score on a per–coronary artery basis.
Subsequently, 0.4 mg of nitroglycerine was sublingually administered to all patients. Patients were given 70 to 80 mL of contrast agent (Bayer Healthcare Pharmaceuticals), followed by a 50- to 67-mL mixed contrast/saline solution bolus and 30 to 40 mL of intravenous saline solution (injected at a rate of 6-6.7 mL/s). The contrast/saline solution bolus consisted of a 50%/50% mixture for the dialysis cohort and a 30%/70% mixture for the non-CKD group. Coronary CT angiography was performed by using a prospectively electrocardiographically triggered sequential scan (≤60 beats/min) or retrospectively electrocardiographically gated helical scan (>60 beats/min). Depending on body mass, tube voltage ranged between 80 and 120 kV peak, and tube current, between 200 and 300 mA for prospectively triggered scans and 600 mA for retrospectively gated scans. Images were reconstructed with a section thickness of 0.9 mm and an increment of 0.45 mm using a standard kernel.

Two X-ray tubes were used to capture DECT angiography images using a scanner (Siemens, Germany). The scanners had the following settings: Reformatted section thickness and increment: 1.0 mm and 0.7 mm; reference tube current-time product: for the 90-kVp tube (90 mAs) and Sn150-kVp tube (69 mAs); collimation: 128 × 0.6 mm; rotation time: 0.25 s. Following a bolus injection of 30–40 ml of saline, the recruited patients received contrast agent (Bayer, Germany) into the vein (5 ml/s, 1.5 ml/kg). Software (syngo.via VB20A, Germany) was used to evaluate the DECT angiography data. The VNC and VM (40–140 keV, 20-keV interval) images of the infarcted region were reconstructed derive from contrast-enhanced images.