Subtraction helical CT angiography of intra- and extracranial vessels: technical considerations and preliminary experience

BACKGROUND AND PURPOSE: Reported CT angiographic (CTA) subtraction methods are not simple, robust, or real time. We investigated a novel technique for semiautomated digital subtraction CTA of the intracranial and extracranial arteries. METHODS: Thirty patients underwent precontrast (low milliampere-seconds) and postcontrast (pitch, 1.5; collimation, 1-2.5 mm) helical imaging with a vacuum-type head holder to facilitate image registration and minimize movement. A reconstructed three-dimensional model of the precontrast bone dataset was subtracted from the postcontrast dataset to produce subtracted maximum-intensity-projection angiograms. Experienced (operator 1) and less-experienced (operator 2) staff performed the standard and subtraction reconstructions, and image generation time and quality (graded 1-5) were compared. A third operator blinded to the method assessed the hard-copy image quality. RESULTS: Image quality with subtraction postprocessing was significantly better with both operators (operator 1, mean improvement of 0.87 grade, median improvement of 1 grade, P <.001; operator 2, mean improvement of 0.63 grade, median improvement of 1 grade, P <.001). Hard-copy image quality was better with the subtraction method (operator 1, P >.001; operator 2, P <.001). Blood vessels at the base of the brain were better demonstrated on subtraction images in 13 of 14 examinations. For the less experienced operator, the reconstruction time was significantly less with the subtraction method than with the conventional method (mean, 7.5 vs 10.1 minutes; P =.001). CONCLUSION: When separation of the vasculature from bone is important and technically difficult, digital subtraction CTA offers a potential advantage. This semiautomated technique is fast and easy to learn, and variably experienced staff can use it.     

CT angiography and MR angiography in the evaluation of extracranial carotid vascular disease

CTA and MRA techniques likely will continue to increase in use in the evaluation of the extracranial cerebrovascular system. The increasing reliance on noninvasive tests mirrors an overall concern with the risks and costs of more invasive examinations. Given the rapid development of the computer technology, data acquisition, and reconstruction algorithms in the past few years, it is apparent that CTA and MRA also will continue to improve.     

双源CT肾血管成像技术术前评价亲属肾移植供肾的价值

目的 探讨双源CT肾血管成像技术(CTA)在亲属肾移植术前评估中的应用价值.方法 对78例亲属肾移植供体术前行供肾双源CT扫描,并采用三维重建技术重建肾动静脉.结果 重建显示肾动脉的解剖类型包括:单支肾动脉93例(左肾46例,右肾47例)、双主肾动脉18例(左肾8例,右肾10例)、副肾动脉16例(左肾11例,右肾5例)、混合型(副肾动脉+双肾动脉)3例(左肾1例,右肾2例)、肾动脉提前分支24例(左肾10例,右肾14例)、肾动脉狭窄2例.肾静脉的解剖类型包括:单支肾静脉140例(左肾75例,右肾65例)、环主动脉左肾静脉2例、主动脉后左肾静脉1例、右肾双肾静脉13例.结论 双源CT肾血管成像技术能真实地反映肾动静脉解剖及其变异,可以为亲属肾移植术前选择供肾、制订手术方案提供参考.     

Comparison of spiral CT angiography with conventional digital subtraction angiography in the evaluation of renal transplant donors: a pilot study

Conventional digital subtraction renal arteriography (IA-DSA) has been traditionally used as the preoperative imaging modality for assessment of renal vascular anatomy for renal transplant donors. This study evaluates the potential use of spiral CT angiography in replacing IA-DSA in the preoperative assessment of this group of patients. Seven patients underwent both spiral CT angiography and IA-DSA between October 1997 and April 1998. It is concluded that spiral CT angiography can demonstrate the number, length and location of renal arteries and it is suggested that spiral CT angiography can potentially replace IA-DSA in the preoperative assessment of renal donors.     

双源CT在冠状动脉造影技术方法的探讨

目的：探讨双源CT（DSCT）对冠状动脉造影具有再次重新定义的价值。方法：对520例患者进行常规冠脉造影检查,分析双源CT冠状动脉造影的技术方法,步骤及特殊的射线剂量调控技术（适应ECG门控剂量调控技术）及其功能。结果：520例患者中心率小于100次／min的患者共有390例,占75％,其平均心率为75±5．6次／min（60—100次／min）。心率高于100的患者有130例,占25％,其平均心率为（110．6＋10．8）次／min（101～130次／min）。冠状动脉重建的最佳时相均为心脏收缩期。结论：双源CT比传统CT少50％的放射剂量,在不需要控制心率的情况下完成心脏成像,提供高质量的冠状动脉和心脏图像,提高诊断冠状动脉病变的准确性。     

Dynamic 3D MR angiography of intra- and extracranial vascular malformations at 3T: a technical note

Time-resolved, contrast-enhanced 3D MR angiography combined with parallel imaging at 3T was applied to an intracranial arteriovenous malformation, a dural arteriovenous fistula, and an extracranial facial arteriovenous malformation. The temporal resolution was one image every 1.5 seconds. Arterial feeders were depicted in all three cases. Early venous drainage was observed in the intracerebral arteriovenous malformation and the dural arteriovenous fistula, but not in the facial arteriovenous malformation. All findings were concordant with conventional angiography.     

MR imaging and MR angiography in preoperative evaluation of intracranial meningiomas

A group of 41 patients with intracranial meningiomas were examined by MR imaging (MRI) and MR angiography (MRA) to assess the. clinical value of MRA in the preoperative evaluation of these patients. The results of MRA were compared with the results of intraarterial cerebral catheter X-ray angiography (XRA; n = 19) and with the operative findings (n = 41 ): Our results showed a good correlation between MRA and XRA/surgery in demonstrating the relationship between the tumor and adjacent venous and arterial structures. Use of MRA was also helpful in demonstrating the degree of intrinsic tumor vascularity. It also supplied important information for operative planning Adjunct XRA was mandatory if detailed information about tumor-feeding vessels was requested by the neurosurgeon, especially in highly vascularized angiomatous meningiomas and in meningiomas suspected of tumor feeding by vessels of the internal carotid artery. Correspondence to: A. Goldmann     

双源CT和超声心动图评价左心功能的对比研究

目的：探讨双源CT评价左心功能的临床价值。方法：研究对象包括临床拟诊冠心病患者22例。分别采用双源CT和超声心动图测量左心功能。结果：双源CT冠脉造影检查21／22例获得满意图像。22例舒张末期位于90％R—R间期,20／22例收缩末期位于40％R－R间期。双源CT所测射血分数和超声心动图测量结果明显相关（r=0．72）。结论：双源CT冠脉造影检查测量左心功能准确可靠,有望为冠心病患者左心功能评价提供一项新方法。     

Coronary artery fistula in adults: evaluation with dual-source CT coronary angiography

Objective:

To evaluate the clinical value of dual-source CT (DSCT) coronary angiography in the diagnosis of coronary artery fistula (CAF) in adults.

Methods:

A large cohort of 17,548 patients, who underwent DSCT coronary angiography in our hospital between January 2008 and October 2013, were retrospectively reviewed for CAF. The origin, course and drainage site of CAF and coexisting abnormalities were analysed. The conventional angiography results, treatments and follow-up DSCT images were also evaluated.

Results:

A total of 33 CAFs from 17,548 patients were detected. The incidence of CAF was 0.19% by DSCT. CAF originating from the left coronary artery (LCA) was found in 14 (42.4%) patients, from right coronary artery (RCA) in 4 (12.1%) cases and from both LCA and RCA in 15 (45.5%) patients. The pulmonary artery was the most common site of drainage (28/33, 84.8%). 8 of the 33 (24.2%) cases were associated with aneurysms. Six cases were associated with coronary artery atherosclerosis. Four patients underwent conventional angiography.

Conclusion:

Coronary–pulmonary artery fistula in adults was found more often than in previous studies. CAF commonly originates from LCA or both LCA and RCA in adults. DSCT is a robust tool for investigating the origin, course and drainage site of CAF and coexistent abnormalities.

Advances in knowledge:

A large adult patient cohort who underwent DSCT angiography was reviewed to assess CAFs. Coronary–pulmonary artery fistula in adults was found more often than in previous studies. CAF was observed to originate from the LCA or both coronary arteries in adults. DSCT could clearly depict the fistula origin, course, drainage site and coexisting abnormalities. Conventional angiography results, treatments and follow-up DSCT images were analysed.Coronary artery fistulas (CAFs) are anomalous connections of the coronary arteries. The phenomenon was first described in 1865 by Krause.¹ CAF is considered as a major coronary anomaly by Ogden''s classification.² Most CAFs are congenital. CAFs have an estimated prevalence of 0.002% in the general population; however, they are present in 0.05–0.25% of patients who undergo coronary angiography.^3–5 The traditional diagnosis tool for CAFs is conventional angiography. With the advent of 64-slice multidetector CT in chest and cardiac imaging, the number of incidentally found CAFs has been increasing. The advanced electrocardiogram (ECG)-gated technique of dual-source CT (DSCT) could provide high diagnostic accuracy for the assessment of coronary artery disease.According to prior studies, CAF arises from the right coronary artery (RCA) in approximately 50% of patients.^6–8 In particular, 70% of the CAFs in children (mean age, 2.9 years) originated from the RCA.⁹ In this study, we focused on adult patients. A large cohort of adult patients who underwent DSCT angiography was reviewed to assess CAFs. The CAFs and coexisting abnormalities were analysed.     

MR angiography and preoperative evaluation for laparoscopic donor nephrectomy

OBJECTIVE: The purpose of our study was to evaluate the effectiveness of gadolinium-enhanced MR imaging in imaging arterial, venous, and ureteric anatomy in a group of potential laparoscopic renal donors and to compare our findings with those established at surgery. SUBJECTS AND METHODS: Sixty-four consecutive patients underwent successful laparoscopic donor nephrectomy. Imaging of the kidneys was performed before surgery with MR imaging and breath-hold three-dimensional gadolinium-enhanced MR angiography. All studies were reviewed prospectively by one of two attending radiologists. Results were compared with findings at the time of laparoscopic nephrectomy. RESULTS: Of the 64 patients, MR imaging and MR angiography identified 30 patients with normal arterial, venous, and ureteric anatomy, and concordance was found at surgery in 29 of these patients. Vascular anomalies were depicted on MR imaging in 34 patients, with complete concordance at surgery in 29 patients. The use of MR angiography for revealing arterial anomalies had a sensitivity of 89.4%, specificity of 94.1%, and accuracy of 90.6%. For venous anomalies, there was a sensitivity of 98.3%, specificity of 100%, and accuracy of 98.4%. No important utereric anomalies were identified at surgery or on MR imaging. CONCLUSION: Renal MR imaging and gadolinium-enhanced MR angiography provide a safe, accurate, and minimally invasive means of comprehensive assessment of the potential living renal donor.     

Minidose技术在双源CT心脏扫描中的初步应用

目的：探讨Minidose技术在双源CT（DSCT）冠状动脉成像及左心室功能分析中的应用价值。方法：45例临床怀疑为冠状动脉心脏病的患者行DSCT冠状动脉成像和超声心动图左心室功能检查。DSCT采用序列扫描模式,总扫描时间窗35％～95％R—R间期,其中40％～70％R-R间期时为全电流输出,数据用于冠状动脉重建,其余间期使用全电流的20％输出,数据用于左心室功能分析。依据美国心脏协会冠状动脉分法,将冠脉图像分为16段,并采用4级法对每段图像质量进行评估。将DSCT检查时测量的左心室射血分数值（LVEF）,并与超声心动图所测得的LVEF值为对照进行统计学分析。结果：40例患者顺利完成DscT冠状动脉成像及超声心动图左心室功能分析。共评价冠状动脉525段,其中可用于诊断的节段占97．53％（512／525）,平均辐射剂量为（3．75±0．89）mSv。DSCT与超声心动图所测得的LVEF值差异无统计学意义（t=-1．61,P=0．12〉0．05）,且两者相关性好（r=0．68）。结论：Minidose技术可以用于DSCT冠状动脉成像兼顾左心室功能分析的“一站式”扫描,冠状动脉图像质量较好,左心室功能分析结果可靠,平均辐射剂量低。     

二代双源CT MinDose技术与超声心动图在主动脉瓣狭窄术前评估中的对比研究

目的采用双源CT的MinDose技术（MD-DSCT）及二维超声心动图分别评价并比较主动脉瓣狭窄患者的冠状动脉、瓣环直径及心功能。方法回顾性分析33例欲行换瓣治疗的主动脉瓣狭窄患者。MD-DSCT检查仅于全RR间期的10%间期全剂量曝光,于70%RR间期双斜轴向图像重建。超声心动图及MD-DSCT采分别测量左室射血分数（LVEF）和主动脉瓣环直径（AVAD）。结果所有患者MD-DSCT检查评价冠状动脉均获得良好效果。LVEF-2D与LVEF-MD-DSCT有较强的相关性（r=0.96,P〈0.01）。AVAD-2D与AVAD-MD-DSCT有较强的相关性（r=0.91,P〈0.01）。结论 MD-DSCT可以于术前一站式评价主动脉瓣狭窄患者的冠状动脉、LVEF以及AVAD。     

Preoperative evaluation of living renal donors: comparison of CT angiography and MR angiography

PURPOSE: To compare computed tomographic (CT) angiography and magnetic resonance (MR) angiography for preoperative evaluation of living renal donors. MATERIALS AND METHODS: Thirty-five living renal donors underwent preoperative contrast material-enhanced CT angiography and gadolinium-enhanced MR angiography. Each study was interpreted by two independent radiologists blinded to all other studies and to interpretations provided by other reviewers. Eighteen kidneys had surgical correlation. RESULTS: CT demonstrated 33 supernumerary arteries in 19 patients, bilateral solitary arteries in 16 patients, and 18 proximal arterial branches in 16 patients. MR demonstrated 26 supernumerary arteries in 15 patients, bilateral solitary renal arteries in 20 patients, and 21 proximal arterial branches in 16 patients. Interobserver agreements for MR (kappa = 0. 74) and CT (kappa = 0.73) were similar to the agreement between MR and CT (kappa = 0.74). Among the kidneys chosen for nephrectomy, one small accessory artery and one proximal arterial branch were missed with CT and MR. Two of the accessory arteries suggested at CT were not found at nephrectomy. By averaging data for both modalities, supernumerary arteries were present in 49% of kidney donors and were bilateral in approximately 17%. Proximal arterial branches were present in 46% of kidney donors. CONCLUSION: Preoperative CT and MR angiography of the renal arteries in renal donors demonstrate substantial agreement. Interobserver disagreement in the interpretation of CT and MR angiograms is related to 1-2-mm-diameter vessels.