Multislice CT virtual intravascular endoscopy of aortic dissection: A pictorial essay

AIM: To present our experience of using 3D virtual intravascular endoscopy (VIE) to characterize and evaluate the intraluminal appearances of aortic dissection.METHODS: Ten patients with known aortic dissection underwent dual-source computed tomography angiography and were included in the study. In addition to 2D axial and multiplanar reformatted images as well as 3D reconstructions, VIE images were created in each patient to demonstrate intraluminal views of the aorta and its branches, origin of artery branches and artery branch involvement by aortic dissection.RESULTS: Stanford A dissection was found in 8 patients and B dissection in the remaining 2 patients. VIE images were successfully generated in all of the patients with excellent visualization of the normal anatomical structures, intimal flap and intimal entrance tear, communication between true and false lumens, as well as assessment of the extent of aortic dissection.CONCLUSION: Our preliminary experience suggests that VIE could be used as a complementary tool to assist radiologists accurately evaluate aortic dissection so that better patient management can be achieved.     

肺空洞多层螺旋CT仿真内镜成像初探

目的 :探讨肺空洞病变多层螺旋CT仿真内镜 (CTVE)成像技术及其初步临床运用。方法 :选择 13例肺空洞患者进行常规横断面CT扫描 ,将容积数据重建后输入GEAW 4.0工作站 ,用三维导航软件 (Navigator)重建成仿真内镜图像 ,调整阈值及视角并用伪彩技术立体观察空洞内表面情况。结果 :癌性空洞 8例 ,肺脓疡空洞 3例 ,结核性空洞 2例。癌性空洞内壁不规则 ,多伴大小不等壁结节 ,表面光滑 ;肺脓疡空洞内壁毛糙 ,显示多发锯齿状、柱状、火山口状改变 ;结核性空洞内壁光滑、规则 ,无结节状改变。对于直径 >3cm空洞 ,CTVE可较满意地获得立体的肺空洞内表面图像 ,空洞内结节的形态、大小、数量以及与空洞内壁联结关系 ,对直径 1.5～ 3 .0cm空洞 ,需调节适当阈值 ,扩大视角显示较好 ;对直径 <1.5cm空洞 ,CTVE显示困难。结论 :肺空洞CTVE成像是对常规CT重要补充 ,但不能作为独立诊断依据 ,必须结合CT原始图像及重建图像进行综合分析     

Optimal scanning protocol of multislice CT virtual intravascular endoscopy in pre-aortic stent grafting: in vitro phantom study

OBJECTIVE: To investigate the optimal scanning protocol for multislice computed tomography angiography (MSCT) in pre-aortic stent grafting observed with virtual intravascular endoscopy (VIE). MATERIALS AND METHODS: The study was performed on a human abdominal aortic phantom which was housed in a perspex container, filled with contrast medium having CT attenuation similar to that used in the patient's abdominal CT scan. A series of scans were performed on a four-slice multislice CT scanner with the scanning protocols as follows: section thickness of 1.3, 3.2 and 6.5 mm, pitch value of 0.875, 1.25 and 1.75 with reconstruction intervals of 50% overlap. The degree of stair-step artifacts was measured at three different locations, superior mesenteric artery (SMA), renal ostium and the normal abdominal aorta. Standard deviation (S.D.) of the signal intensity measured on surface shaded images was used to determine the image quality. Radiation dose was also recorded in each scanning protocol. RESULTS: The VIE images showed that image quality was not dependent on pitch and section thickness in the visualization of renal ostium and SMA, whereas it was dependent on these two factors at the level of the normal aorta (p<0.05). It was noticed that when section thickness reached 6.5 mm the SMA and renal ostia became distorted. Radiation dose measured in 1.3 mm protocols was significantly higher that those measured in other section thicknesses (p<0.05). CONCLUSION: The scanning protocol of section thickness 3.2 mm, pitch 1.25 with a reconstruction interval of 1.6 mm was recommended as it allows optimal visualization of VIE images of aortic ostia, generation of fewer artifacts and less radiation dose.     

Endovascular abdominal aortic aneurysm repair and renal complications: a comparison between suprarenal and infrarenal fixation of stent grafts

PURPOSE: This study was performed to compare the rate of morphological (renal infarction and/or ischaemic lesions) and functional renal complications after the suprarenal and infrarenal fixation of aortic stent-grafts for endovascular abdominal aortic aneurysm repair (EVAR). MATERIALS AND METHODS: We retrospectively reviewed all followup computed tomography (CT) angiograms (obtained at 1, 6 and 12 months and yearly thereafter) and laboratory data pertaining to 102 patients who underwent suprarenal (60 patients, group A) or infrarenal (42 patients, group B) placement of aortic stent-grafts. The groups were compared in terms of complications affecting kidney function (creatinine clearance) and morphology (renal artery steno-occlusions, morphological and structural parenchymal changes), and pre- and postprocedural arterial pressure (AP). RESULTS: Analysis of patient demographics revealed no statistically significant difference between the two groups. The proximal neck was shorter in group A (2.14 cm+/-0.84 cm) than in group B (3.41 cm+/-1.21 cm). Creatinine clearance (CrCl) decreased in both groups (group A: from 64.24 ml/min to 60.66 ml/min; group B: from 72.41 ml/min to 68.73 ml/min) without any significant difference in terms of changes in renal function (CrCl variation: -8.75% vs. -6.4%) or morphology (post-EVAR stenosis: 2.6% vs. 0%; progression of existing steno-occlusive lesions: 1% vs. 0%; ischaemic lesions: 3.2% vs. 0%), or in AP. CONCLUSIONS: In our experience, the use of abdominal endografts with suprarenal fixation did not lead to any significant increase in morphological and/or functional renal complications compared with those with infrarenal fixation.     

CT virtual intravascular endoscopy assessment of coronary artery plaques: A preliminary study

Purpose

The purpose of this study was to investigate the potential value of CT virtual intravascular endoscopy (VIE) in the visualization and assessment of coronary plaques in patients suspected of coronary artery disease.

Materials and methods

20 (13 men, 7 women, mean age 54 years) consecutive patients with suspected coronary artery disease undergoing 64-slice CT angiography were included in the study. Four main coronary artery branches were assessed with regard to the presence of coronary plaques based on 2D axial, multiplanar reformation, 3D volume rendering and VIE visualizations. The coronary plaques were characterized into calcified, noncalcified and mixed plaques. The intraluminal appearances of these coronary plaques were demonstrated with VIE images and correlated with 2D and 3D images to determine the diagnostic value of VIE for the assessment of the plaques.

Results

VIE was able to identify and demonstrate the intraluminal appearances of coronary plaques in 18 patients involving 32 coronary artery branches which were shown as an irregularly intraluminal protruding sign in extensively calcified plaques and smooth protruding appearance in noncalcified or focally calcified plaques. An irregular intraluminal appearance was also noticed in the presence of mixed plaques due to variable components with different CT attenuations contained within the plaques. VIE accurately confirmed the degree of coronary stenosis or occlusion despite the presence of heavy calcification.

Conclusion

VIE could be used as a complementary tool to conventional CT visualizations for the analysis of luminal changes and assessment of disease extent caused by the coronary plaques.     

多层螺旋CT仿真内窥镜在血管病变诊断中的应用

目的 探讨多层螺旋CT(MSCT)仿真内窥镜(VE)对血管病变的显示能力和临床应用价值。方法 对56例血管病变进行CTVE成像，其中32例还进行了DSA检查，18例经手术证实(其中3例同时还作了DSA检查)，9例肺动脉栓塞经内科其他检查及溶栓治疗而得到证实。结果 56例血管病变中均获得了满意的CTVE图像，良好地显示了血管内腔内壁、附壁血栓、钙化斑块、血管狭窄，以及动脉夹层的内膜片和假性动脉瘤破裂口的形态、大小及与正常血管的解剖关系。32例DSA检查病例中CTVE对病变的显示有24例(显示率为75％)，18例手术病人中CTVE对病变的显示有17例，9例肺动脉栓塞病例CTVE全部显示，差异无显著性意义(X^2=5．2809，P=0．071)。CTVE对血管病变的显示能力对照DSA(32例)、手术(18例)和内科证实的9例肺动脉栓塞具有一致性，56例血管病变CTVE总的显示率为84%(47／56)。结论 CTVE能较好的显示血管腔内的情况，结合其他血管二、三维成像可以明确诊断多种血管疾病，帮助和指导手术，具有独特的应用价值。     

国产覆膜支架介入治疗腹主动脉瘤的实验研究

 目的建立10只犬腹主动脉瘤模型,以介入法置入国产覆膜支架,观察其改变.方法10只实验动物建立模型;国产覆膜支架治疗后,CT进行影像学复查;最后取病理检查.结果两只发生并发症,余犬治疗后管腔通畅,但局部管腔有狭窄,病理电镜示覆膜支架内有内皮细胞生长.结论国产覆膜支架介入治疗腹主动脉瘤安全、有效.     

Infected abdominal aortic aneurysm due to salmonella: CT evaluation

Two cases of infected abdominal aortic aneurysm (IAAA) caused by salmonella are reported and the computed tomography (CT) features are discussed and compared with the pathologic findings. Additionally, a review of the literature was performed. A well-enhanced para-aortic mass (PAM) beyond the calcified intima of the abdominal aorta on the CT, which was initially considered to represent a leakage from the infected aneurysm, was observed in 5 of the 6 reported cases (including ours) and identified as a pseudoaneurysm. In one case, multiple gas collections within the PAM were demonstrated for the first time in IAAA due to salmonella.     

CT仿真内窥镜在主动脉病变诊断中的应用

目的　探讨CT仿真内窥镜 (CTvirtualendoscopy,CTVE)对主动脉病变的显示能力和临床应用价值。方法　对 147例主动脉病变进行CTVE成像 ,5 8例并行DSA检查 ,37例经手术证实。结果(1) 147例主动脉中 ,139例获得了满意的CTVE图像。 (2 )CTVE良好地显示了血管内腔内壁 ,夹层动脉的内膜瓣 ,假性动脉瘤的破口。结论　CTVE集内镜与CT血管成像 (CTA)的优点于一身 ,可以明确诊断各种动脉疾病 ,帮助和指导手术 ,有着独特的应用价值。     

CT of inflammatory abdominal aortic aneurysm: development from an uncomplicated atherosclerotic aneurysm.

The etiology and natural history of inflammatory abdominal aortic aneurysm are poorly understood. We report a case of inflammatory abdominal aortic aneurysm that developed from an uncomplicated aneurysm over a period of 6 1/2 months.     

Endovascular repair of abdominal aortic aneurysm: helical CT findings]

Endovascular repair of infrarenal abdominal aortic aneurysms is currently widely diffuse. Imaging plays a major role in the preprocedural patient evaluation, implantation of stent-graft, and patient follow-up. The aim of this paper is to describe the more frequent findings that can be seen in CT examinations after endovascular repair of infrarenal abdominal aortic aneurysm. We discuss CT findings related to the aneurysm (size, exclusion with complete perigraft thrombosis, back-filling of aneurysm sac via branch vessels) and to the device (dislocation, rotation, kinking, device expansion, patency/thrombosis, device disruption). We also show some examples of incorrect assembly of the modular components of the stent-graft.     

不使用造影剂的腹主动脉瘤腔内隔绝术

目的：探讨一种不使用造影剂的腹主动脉瘤（AAA）腔内隔绝术（EVE），治疗合并肾功能不全的AAA患者。方法：对3例合并肾功能不全的AAA患者在不使用造影剂条件下实施AAA EVE，并对术前评估内容进行分析。结果：3例患者手术均获成功，2例采用分叉型移植物，1例采用直型移植物。术后随访结果表明，动脉瘤被完全隔绝，无内漏，瘤腔内血栓形成；移植物内血流通畅，周围无异常血充。结论：选择近端瘤颈较长的患者，术前对肾动脉及髂内动脉开口位置等指标进行准确评估，不使用造影剂同样可以完成AAA EVE。     

Multislice CT angiography in aortic stent grafting: relationship between image noise and body mass index

PURPOSE: To investigate the correlation between image noise and body mass index (BMI) in multislice CT angiography (MSCT) for patients with abdominal aortic aneurysm (AAA) treated with endovascular stent grafts. MATERIALS AND METHODS: Seventeen patients who underwent MSCT following endovascular repair of AAA were included in the study. Image noise (standard deviation of the CT attenuation: S.D.) and signal to noise ratio (SNR) were plotted against BMI to demonstrate the correlation using a linear regression method. Image quality of 3D reconstructions was correlated to the SNR and BMI. RESULTS: The r-value of linear regression between S.D. and BMI was 0.578 (p<0.05), 0.835 and 0.802 (p<0.001), respectively, at the level of renal artery, aortic aneurysm and common iliac artery. The r-value of linear regression between SNR and BMI was 0.332, 0.516 and 0.552 (p<0.05), respectively, at above three levels. Image quality of 3D reconstructions was compromised in five patients and diagnosis was affected in two patients with BMI more than 30. CONCLUSION: A significant correlation was observed between image noise and BMI in MSCT angiography of endovascular repair of AAA. Our findings are valuable for optimisation of MSCT angiography scanning protocols and reduction of radiation dose in MSCT examinations.     

双源CT血管成像在腹主动脉瘤中的临床应用价值

目的：评价双源CT血管成像在腹主动脉瘤中的临床应用价值。方法：回顾性分析33例接受双源CT血管造影及主动脉造影检查确诊为腹主动脉瘤患者的影像资料。所有图像均行三维重建后处理及分析,观察腹主动脉瘤的部位、形态、分型、范围,并对腹主动脉瘤进行分型及相关测量。结果：33例腹主动脉瘤中,5例为近肾型,28例为肾下型。双源CT对瘤体长度、大小,近端及远端瘤颈长度、直径。近端瘤颈与动脉瘤长轴夹角测量准确。结论：双源CT可准确诊断腹主动脉瘤,并且可以提供详细而准确术前信息,是腹主动脉瘤术前诊断和术前评价的首选影像学检查方法。     

腹内疝的多层螺旋CT诊断

腹内疝并不常见，因其容易形成闭襻，发生绞窄性肠梗阻，致死率极高（〉50％），早期手术干预可以大大降低其严重并发症的发生率和死亡率。由于临床诊断困难，影像学诊断显得尤为重要。本文旨在探讨腹内疝的分型和多层螺旋CT影像学特点，为手术治疗提供依据。