Dose modulated retrospective ECG-gated versus non-gated 64-row CT angiography of the aorta at the same radiation dose: comparison of motion artifacts, diagnostic confidence and signal-to-noise-ratios

Purpose

To compare ECG-gated and non-gated CT angiography of the aorta at the same radiation dose, with regard to motion artifacts (MA), diagnostic confidence (DC) and signal-to-noise-ratios (SNRs).

Materials and methods

Sixty consecutive patients prospectively randomized into two groups underwent 64-row CT angiography, with or without dose-modulated ECG-gating, of the entire aorta, due to several pathologies of the ascending aorta. MA and DC were both assessed using a four-point scale. SNRs were calculated by dividing the mean enhancement by the standard deviation. The dose-length-product (DLP) of each examination was recorded and the effective dose was estimated.

Results

Dose-modulated ECG-gating showed statistically significant advantages over non-gated CT angiography, with regard to MA (p < 0.001) and DC (p < 0.001), at the aortic valve, at the origin of the coronary arteries, and at the dissection membrane, with a significant correlation (p < 0.001) between MA and DC. At the aortic wall, however, ECG-gated CT angiography showed statistically significant fewer MA (p < 0.001), but not a statistically significant higher DC (p = 0.137) compared to non-gated CT angiography. At the supra-aortic vessels and the descending aorta, the ECG-triggering showed no statistically significant differences with regard to MA (p = 0.861 and 0.526, respectively) and DC (p = 1.88 and 0.728, respectively). The effective dose of ECG-gated CT angiography (23.24 mSv; range, 18.43–25.94 mSv) did not differ significantly (p = 0.051) from that of non-gated CT angiography (24.28 mSv; range, 19.37–29.27 mSv).

Conclusion

ECG-gated CT angiography of the entire aorta reduces MA and results in a higher DC with the same SNR, compared to non-gated CT angiography at the same radiation dose.     

Predictability of aortic dissection as a function of aortic diameter

The role of aortic diameter on the occurrence of type A dissectionwas investigated in 73 patients with dilated ascending aortaat the lime of pre-operative evaluation. Using transthoracicechocardiography for diagnosis and measurements, 54 patientswere identified with type A dissection (group 1) and 19 withoutdissection (group 2). The true mean aortic diameters were identical(6·0±1·3 cm in group 1 and 6·4±1·4cm in group 2; mean±SD; ns) as were the indexed aorticdiameters (ratio of diameter/body surface area; 3·2±0·8cm . m^–12 and 3·4±0·7cm m^–2respectively; ns). However, the individual diameters showeda pronounced scatter in both groups (range from 3·6±11·0cm). Of the 73 patients, 66 had surgery (47/54 with and 19/19without dissection) and seven patients were treated medically.Emergency surgery was performed in 45/66 patients (all withacute type A dissection) andelective repair in 21/66 (19 withoutand two with chronic type A dissection). In-hospital mortalitywas 18% in the emergency group, 5% in the elective group and57% in the medical group. It is concluded that patients with dilated ascending aorta havea substantial incidence of acute dissection. Their clinicalcourse is unpredictable; acute dissection occurs in some, andin others the ascending aorta continues to enlarge without dissection.Because patients with dissection often arrive too late for electiverepair andhave to be operated on as emergencies with a higheroperative risk, we recommend elective surgery before the diameterof the ascending aorta has reached 6 cm.     

Traumatic dissection of the circumflex coronary artery complicating a myocardial contusion. A case report

Myocardial contusion can result in lethal complications as myocardial infarction, tamponade and acute valvular lesions. Following blunt thoracic trauma, the diagnosis is often difficult to make because of the multiple associated injuries. We report the case of a 42-year-old woman who, after a blunt chest trauma, developed a tamponade, an acute transmural myocardial infarction and an acute mitral regurgitation. Coronary arteriography revealed a dissection in the circumflex artery.     

球囊在预防Ⅲ度及以上宫腔黏连分离术后再黏连的临床研究

目的探讨球囊对宫腔镜下重度宫腔黏连分离术（TCRA）后预防再次宫腔黏连的临床效果。方法选择宫腔镜检查证实有Ⅲ度及以上宫腔黏连并成功分离黏连者40例,按照就诊顺序随机置环＋透明质酸钠、球囊＋置环＋透明质酸钠。随访3个月,再次宫腔镜检查2组的治疗效果,进行分析比较。结果Ⅲ度及以上黏连的患者,球囊＋置环＋透明质酸钠组的总有效率高于置环＋透明质酸钠,差异有统计学意义（P〈0.05）。结论宫腔镜分离宫腔黏连后,球囊＋置环＋透明质酸钠能有效预防宫腔再次黏连。     

Dissection of the descending aorta complicated by preeclampsia at 30 weeks of gestation: medical treatment and caesarean delivery

The authors report the case of a dissection of the descending thoracic aorta in a woman in the third trimester of the pregnancy. After an initial medical therapy by a combination of three intravenous anti-hypertensive medications, a caesarean section was decided under general anaesthesia at 30 weeks of gestation as the result of the occurrence of a severe preeclampsia. The aetiology, diagnosis, and anaesthetic management are discussed.     

左主干开口于无冠窦急性前壁心肌梗死经皮冠状动脉支架术致左主干回旋支夹层一例

1 病例资料 患者男性,54岁,因持续性心前区疼痛5h入院。既往史：吸烟。查体：BP120／80mmHg（1nllnHg=0．133kPa）,神清,自动体位,查体合作。口唇无发绀,颈静脉无怒张;肺呼吸音清,未闻及干湿哕音,心界无扩大,心率100次／min,节律规整,未闻及杂音,肝脾正常,双下肢无水肿。     

Immediate bail-out TAP-stenting for the treatment of iatrogenic aortocoronary dissection involving left main bifurcation

Iatrogenic aortocoronary dissection is a rare but potentially disastrous complication of percutaneous coronary intervention. The left main dissection extending into distal bifurcation involving both the left anterior descending and left circumflex is a complex and vital complication, which is classified as Eshtehardi Type II dissection. We presented a case of iatrogenic left main coronary artery dissection with upcoming closure of both major branches, which was successfully managed by immediate bail-out TAP-stenting. The 77-year-old patient was dis-charged without any complication, and 1-year follow-up indicated stent patency and favorable clinical result. Immediate bail-out stenting is a feasible and reasonable initial management for this lethal complication.     

MRI in spontaneous dissection of vertebral and carotid arteries

Summary Fifteen patients were observed between 1987 and 1990: there were six with angiographically confirmed vertebral artery dissection, and 9 with carotid artery dissection. Results showed concordance of MRI and angiographic findings, in all cases but one. The dissected portion consistently showed a semilunar hyperintensity narrowing the residual eccentric signal void of the lumen when the artery was not completely occluded. In one angiographically occluded vessel, MR detected a small signal void within the hyperintensity, indicating that the artery was not completely occluded. The length of the dissected portion was clearly demonstrated by MR. Follow up MR and angiographic studies confirmed the regression of the dissection, and also allowed examination of the cerebral parenchyma.     

Spontaneous healing of cervical pseudoaneurysm in vertebral artery dissection under anticoagulant therapy

We report a 41-year-old woman with embolic stroke of the mid-pons attributed to embolism from vertebral artery dissection. Angiography revealed an occluded artery on one side and an incidental pseudoaneurysm of the midcervical portion of the vertebral artery on the other. After 3 months of warfarin therapy control angiography showed complete occlusion of the pseudoaneurysm. We discuss therapeutic choices and review the literature. Received: 3 January 1997 Accepted: 26 January 1997     

76株耐甲氧西林金黄色葡萄球菌的分离鉴定与药敏试验

收集临床标本中鉴定的金黄色葡萄球菌238株,按耐甲氧西林金黄色葡萄球菌鉴定方法进行分离鉴定和药敏试验。结果:检出MRSA76株,检出率为31.9％。MRSA对万古霉素、丁胺卡那霉素、利福平、头孢噻吩、氟哌酸较敏感,而对其它常用抗生素均有很高的耐药率。