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To investigate the effects of 80-kilovoltage (kV) tube voltage coronary computed tomographic angiography (CCTA) with a reduced amount of contrast agent on qualitative and quantitative image quality parameters and on radiation dose in patients with a body mass index (BMI)23.0 kg/m(2).One hundred and twenty consecutive patients with a BMI23.0 kg/m(2) and a low calcium load undergoing retrospective electrocardiogram (ECG)-gated dual-source CCTA were randomized into two groups [standard-tube voltage (120-kV) vs. low-tube voltage (80-kV)]. The injection flow rate of contrast agent (350 mg I/mL) was adjusted to body weight of each patient (4.5-5.5 mL/s in the 120-kV group and 2.8-3.8 mL/s in the 80-kV group). Radiation and contrast agent doses were evaluated. Quantitative image quality parameters and figure of merit (FOM) of coronary artery were evaluated. Each coronary segment was evaluated for image quality on a 4-point scale.Compared with the 120-kV group, effective dose and amount of contrast agent in the 80-kV group were decreased by 57.8% and 30.5% (effective dose:2.7 ± 0.5 vs. 6.4 ± 1.3 mSv; amount of contrast agent:57.1 ± 3.2 vs. 82.1 ± 6.1 mL; both p0.0001), respectively. Image noise was 22.7 ± 2.1HU for 120-kV images and 33.2 ± 5.2 HU for 80-kV images (p0.0001). Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) in the proximal right coronary artery (RCA) and left main coronary artery (LMA) were all lower in 80-kV than 120-kV images (SNR in the proximal RCA: 16.5 ± 1.8 vs. 19.4 ± 2.8; SNR in the LMA: 16.3 ± 2.0 vs.19.6 ± 2.7; CNR in the proximal RCA: 19.4 ± 2.3 vs.22.9 ± 3.0; CNR in the LMA: 18.8 ± 2.4 vs. 22.7 ± 2.9; all p0.0001). FOM were all significantly higher in 80-kV than 120-kV images (proximal RCA: 146.7 ± 45.1 vs. 93.4 ± 32.0; LMA: 139.1 ± 47.2 vs. 91.6 ± 31.1; all p0.0001). There was no significant difference in image quality score between the two groups (3.3 ± 0.8 vs. 3.3 ± 0.8, p=0.068) despite decreased SNR and CNR of coronary artery in the 80-kV group.The 80-kV protocol significantly reduces radiation and contrast agent doses in CCTA in patients with a low BMI23.0 kg/m(2) and a low calcium load while maintaining image quality.

Background Surgical management of acute type A dissection with the tear in the descending aorta is challenging because of the technical difficulty in managing proximal and distal aortic lesions through a median sternotomy or lateral thoracotomy using a single-stage procedure. Methods Thirty-three patients with acute type A dissection with the tear in the descending aorta underwent total arch replacement combined with stented elephant trunk implantation through a median sternotomy from April 2003 to June 2007. Preoperative complications included acute cardiac tamponade (n = 1), acute left heart failure (n = 1), acute myocardial infarction (n = 1), cerebral ischemia (n = 1), acute renal failure (n = 2), chronic renal dysfunction (n = 2), and acute mesenteric ischemia (n = 1) and lower extremity ischemia (n = 3). The residual false lumen was evaluated using postoperative computed tomography. Results Death at 30 days was 6.06% (2 of 33 patients). One patient with preoperative mesenteric ischemia died of postoperative multiple-organ failure. One patient with preoperative acute renal failure ceased treatment after three reoperations owing to uncontrollable bleeding. Left lower-extremity paraparesis occurred in 1 patient, and transient neurologic dysfunction occurred in 1 patient. Severe complications were not observed at a mean follow-up of 25 ± 11 months. Thrombus obliteration of the false lumen was observed at the distal end of the stented graft in 29 patients (96.7%) and at the diaphragmatic level in 20 patients (66.7%) during follow-up. Conclusions Encouraging outcomes favor this technique in patients with acute type A dissection with the tear in the descending aorta. Simultaneous repair of proximal aortic lesions and thrombosis of the false lumen in the descending aorta could be obtained.

Background The purpose of the study was to assess the efficacy of total arch replacement combined with stented elephant trunk implantation for Marfan patients with acute Stanford type A aortic dissection involving the aortic arch. Methods Between January 2004 and April 2006, 13 consecutive Marfan patients (4 female, 9 male) with acute type A aortic dissection involving the aortic arch underwent total arch replacement combined with implantation of a stented elephant trunk. Aortic dissection extending to the iliac artery was seen in 10 patients, and to the abdominal aorta in 3 patients. Ages ranged from 17 to 65 years (mean, 39 ± 13). Computed tomography was done to evaluate the residual false lumen in the descending aorta. Results All patients survived and were discharged from hospital. One patient with thrombosis of the innominate artery suffered cerebral infarction and recovered during follow-up. One patient had ischemia of the left upper limb postoperatively, but recovered after axillary to axillary artery bypass. There was 1 death during the mean follow-up period of 27 ± 10 months. Complete thrombus formation was observed in 84.6% of patients (11 of 13) around the stented elephant trunk, and in 69.2% of patients (9 of 13) at the diaphragmatic level. Conclusions Total arch replacement combined with stented elephant trunk implantation for Marfan patients with acute type A aortic dissection involving the aortic arch results in less late dilatation of the dissected descending aorta. That prolongs the reoperation interval or reduces the number of late thoracoabdominal aortic replacements, unless there is a patent false lumen around the stented elephant trunk.