组合配准减影技术在脑血管减影图像后处理过程中的初步研究

摘要 目的：比较在脑血管数字减影检查术后采用单纯全局减影技术和在全局减影基础上再进行兴趣区局部减影的组合配准减影技术在图像质量上的差别,初步探索利用全局和局部组合配准减影技术来减少运动伪影,提高减影图像质量的可行性和价值。 材料和方法：(1)运用Visual Basic 软件编写全局减影和局部减影程序。(2)运用该程序对模拟实验图像中同一组蒙片和靶片进行两种方法的减影处理,一种是只进行全局配准减影处理的单纯方式,另一种是采用在进行全局减影处理后再行局部配准减影处理的组合方式。比较两种配准减影方法消除图像伪影的能力。(3)用上述方法对10例脑血管成像序列中有明显运动伪影的图像进行减影处理。其中颈总动脉侧位造影3例;汤氏位大脑中动脉动脉期1例和静脉窦期2例;汤氏位椎动脉静脉窦期4例。(4) 目测评价：采用专家目测评论的方法对两种减影结果进行对比。 结果：（1）整个软件运行稳定,操作流程清晰,减影结果正确。（2）在实验图像中,以A区作为配准参考点的单纯全局配准减影显示只有A区获得清晰的血管减影像。同样的蒙片和靶片在经过组合方式配准减影后,A区和B、C、D区中进行了局部配准减影的区域都获得清晰的血管减影像,伪影明显减少。（3）在颈总动脉分叉部侧位造影图像序列中,由于靶片中颈椎的移动导致在单纯全局配准减影图像中出现明显的伪影,经组合配准减影处理后,颈内动脉全段清晰显示。在大脑中动脉汤氏位造影图像序列中,大脑中动脉M2段血管被骨性眼眶的伪影影响,进行组合方式配准减影后,动脉血管清晰显示。在静脉窦期汤氏位全局减影图像中,颅底的骨性伪影对静脉窦影响明显,采用组合方式配准减影后,横窦、乙状窦、海绵窦以及相关侧支回流通路都较清晰显示。（4）目测结果：经过组合方式配准减影处理过的图像,血管显示清晰,没有发生变形、重叠和断裂等失真现象,伪影明显少于只单纯进行全局配准减影的图像。 结论：组合配准减影技术在脑血管减影图像的后处理工作中是一种新型的和有价值的DSA后处理技术,弥补了单纯只进行全局配准减影的缺陷,使减影图像的血管显示能力得到加强。 关键词：组合配准 脑血管 数字减影 全局 局部     

减影CTA阈值调节法测量脑血管径线

目的评价减影CTA中采用阈值调节法测量脑血管径线的准确性。方法收集接受脑血管CTA检查的患者60例,采用阈值调节法测量并比较常规CTA和减影CTA中双侧大脑前动脉、大脑中动脉、颈内动脉的血管径线差异。结果根据常规CTA血管内CT值标化阈值后,减影CTA所测各段血管径线均小于常规CTA测值(P均0.05);分别根据各自图像中血管内CT值标化阈值后,常规CTA和减影CTA所测各段血管径线差异均无统计学意义(P均0.05)。结论减影CTA中采用阈值测量法测量血管径线准确、可靠,具有一定临床应用价值。     

三维增强MR数字减影血管造影诊断下肢动脉硬化闭塞症

目的:探讨三维增强MR数字减影血管造影诊断下肢动脉硬化闭塞症的价值。方法:对83例疑下肢动脉硬化闭塞症的患者行三维增强MR数字减影血管造影检查,用3DFLASH序列(TR/TE 4.6/1.8msec)冠状位采集对比剂注射前后原始图像,先进行减影处理,再进行最大信号强度投影重建,图像质量采用优、良、差3级评价。同时观察三维增强MR数字减影血管造影显示下肢动脉斑块、狭窄、闭塞等情况。结果:图像质量均达到优良并能清晰显示下肢动脉血管结构及病变情况,83例中发现下肢动脉斑块和/或狭窄和/或闭塞72例。结论:三维增强MR数字减影血管造影能较好显示下肢动脉情况,图像分辨率高,是一种简便、易行、有效的诊断下肢动脉硬化闭塞症的影像学检查方法。     

脑血管造影术患者的护理体会

探讨DSA脑血管造影患者的护理,通过观察和分析122例行数字减影脑血管造影术的脑血管病患者手术前、后的病情特点,总结出该技术应用过程中的护理要点和体会.     

数字减影全脑血管造影术的护理配合

回顾性总结46例数字减影全脑血管造影术的护理配合。提出术前全面评估病情、做好健康教育及心理护理，术中注重全身肝素化、严格执行无菌技术，密切观察术中、术后病情变化。积极采取有效的抢救措施是成功配合脑血管造影术的关键。     

容积CT数字减影血管造影与同步匹配蒙片去骨法对颅内动脉瘤的诊断价值比较

目的探讨容积CT数字减影血管造影(VCTDSA)与同步匹配蒙片去骨(MMBE)法对颅内动脉瘤的诊断价值。方法分析临床怀疑颅内动脉瘤、并接受VCTDSA检查的57例患者资料,其中47例经3DDSA和/或手术证实,比较VCTDSA与MMBE的减影图像质量、对动脉瘤的检出率以及二者图像后处理时间。结果57例患者分别采用VCTDSA与同步MMBE的图像质量差异有统计学意义(P0.05)。经手术和/或3DDSA结果证实,47例患者共检出53个动脉瘤;VCTDSA对于IA的检出率为96.23%(51/53),高于MMBE(46/53,86.79%);VCTDSA对于颈内动脉瘤的检出率为94.12%(32/34),高于MMBE(27/34,79.41%)。VCTDSA对于3mm的动脉瘤的检出率为86.67%(13/15),高于MMBE(10/15,66.67%)。VCTDSA的平均后处理时间为(3.87±0.73)min,同步MMBE的平均后处理时间为(4.05±0.79)min,二者差异有统计学意义(P0.05)。结论 VCTDSA是一种方便、快速的检查方法,图像真实、可靠,对颅内动脉瘤的检出与诊断优于同步MMBE。     

示踪减影透视在颅内动脉瘤介入治疗中的临床应用

目的探讨示踪减影透视(TSF)在颅内动脉瘤介入治疗中的临床应用价值。方法 11例接受介入栓塞治疗的颅内动脉瘤患者,术前均接受双源CT血管成像(DSCTA)及全脑数字减影血管造影(DSA)检查,确定动脉瘤的大小、形态、位置,并测量瘤颈及瘤体的直径;术中应用TSF技术。结果 11例患者(共11个动脉瘤)介入栓塞均获得成功,共植入电解可脱弹簧圈39枚,包括1枚3-D标准成篮填充弹簧圈,3枚3-D软成篮填充弹簧圈及35枚柔软型填充弹簧圈。结论对接受颅内动脉瘤介入栓塞治疗的患者,术中应用TSF可提高治疗效果。     

肝脏CT动态增强扫描非刚性对位减影技术的质量评价

目的利用血管减影前后的吻合程度，探讨非刚性对位减影技术在肝脏CT动态增强检查中的质量评价。 方法收集2018年12月至2019年2月于中山大学附属第一医院行肝脏CT动态增强检查的50例患者资料，使用非刚性对位减影技术获得减影图像，对减影前后的图像质量进行评价，定性评价包括图像伪影情况及解剖错配程度，定量评价测量各血管（腹主动脉、肝右动脉、肝左动脉、门静脉主干、门静脉右支、门静脉左支）减影前后在动脉晚期、门静脉晚期的CT值。采用混合线性效应模型及拟合方程评估减影前后各血管的CT值曲线拟合程度。 结果减影后图像均无明显解剖结构错配导致的伪影，3名测量者一致性较高（ICC=0.844，P<0.001）。减影技术一定程度上会降低各血管的CT值，与强化分期不存在交互作用。无论是在动脉晚期还是门静脉晚期，减影前后各血管CT值走势一致，CT值变化曲线吻合。 结论非刚性对位减影技术可轻松实现肝脏CT动态增强检查的图像减影，并获得良好的图像质量。     

同步与非同步扫描对CT数字减影血管造影图像质量的影响

目的探讨同步与非同步扫描对64层容积CT数字减影血管造影（VCTDSA）图像质量的影响。方法建立紧贴骨结构的血管模型,采用64层螺旋CT进行扫描：①未注射对比剂螺旋扫描20次,球管曝光时间为2.1s,扫描间隔时间分别为1.9s、3.9s、5.9s、7.9s、9.9s、11.9s、13.9s、15.9s、17.9s、19.9s,2.9s、4.9s、6.9s、8.9s、10.9s、3.0s、4.0s、5.0s、6.0s、7.0s。②注射对比剂后螺旋扫描10次,扫描间隔时间分别为9.9s、11.9s、13.9s、15.9s、17.9s,10.9s、12.9s、11.0s、12.0s、13.0s,其余扫描参数同①。减影后数据行3D容积再现（VR）及最大密度投影（MIP）图像重组,评价减影后图像质量、测量减影后全幅图像CT值、记录球管曝光角度差。结果注射对比剂前后同步扫描15次,减影后图像质量均为Ⅰ级,非同步扫描15次,减影后图像质量Ⅰ级2次、Ⅱ级12次、Ⅲ级1次;20次未注射对比剂减影后图像CT值比较,非同步扫描减影后图像CT值均数高于同步扫描;同步扫描的球管曝光角度差均数明显小于非同步扫描。结论同步扫描保证球管曝光的起始位置相同,可明显提高VCTDSA的图像质量。     

基于结构光扫描的椎弓根多区域组合配准技术

目的利用术中结构光扫描图像和术前CT进行配准,实现计算机辅助椎弓根手术。方法术前对手术部位的CT图像进行三维重建及区域划分,术中用结构光对其进行三维扫描,把腰椎模型骨各区域组成17个组合,然后结合预配准与多区域ICP算法对两点集进行配准。结果该算法实现了脊椎骨可见光数据与CT数据的配准,即使在噪声干扰和图像偏移的影响下,配准误差仍能保证在1mm之内。结论本文提出的预配准结合多区域配准算法能有效地避免ICP算法的局部收敛性;即使在施加噪声和外部干扰情况下,利用两个区域组合进行配准可以满足手术精度要求。     

低注射速率、低剂量对比剂3D-DSA脑血管造影

目的探讨低注射速率、低剂量对比剂3D-DSA脑血管造影的的可行性。方法连续收集疑似动脉瘤患者51例行3D-DSA脑血管造影,选择DynaCT 5sDSA成像,均采用非离子型对比剂碘普罗胺注射液(370mgI/100ml),导管尖端均位于平枢椎水平,按对比剂注射速率随机分为A组(1.5ml/s,n=18)、B组(2.0ml/s,n=18)、C组(3.0ml/s,n=15)。计算C臂锥形束CT轴位图像颈内动脉岩段(C2段)和眼段(C6段)、大脑中动脉水平段(M1段)、大脑前动脉水平段(A1段)的噪声、SNR及CNR,由2名医师对连续减影图像、VR及MIP重组图像的图像质量进行评分后行统计学分析。结果 B、C组与A组噪声的差异均无统计学意义(P均0.05)。A组与B组比较,M1、A1段的SNR、CNR差异均有统计学意义(P均0.05),C2、C6段SNR、CNR差异均无统计学意义(P均0.05);A组与C组比较,C2、C6、M1及A1段的SNR、CNR差异均有统计学意义(P均0.05)。3组间大脑中动脉、大脑前动脉连续减影图像及VR、MIP图像的图像质量主观评分差异均无统计学意义(P均0.05),均可充分显示颅内动脉瘤情况。结论 3D-DSA脑血管造影中实施个性化低注射速率、低剂量对比剂注射方案可行,能够降低患者碘摄入量及血管破裂出血风险。     

脑动脉硬化患者合并椎动脉异常的临床筛查探讨

目的:探讨以椎动脉数字减影血管造影(DSA)为参照标准,椎动脉超声、经颅多普勒(TCD)、磁共振动脉造影(MRA)、计算机体层动脉造影(CTA)对脑动脉硬化患者合并椎动脉异常的临床筛查、诊断价值。方法:对2006年1月至2010年9月收治的186例脑动脉硬化患者进行回顾性分析,男133例,女53例;年龄30～84岁,平均63.8岁。186例全部行DSA椎动脉造影,172例行椎动脉超声和TCD,53例行MRA,25例行CTA,以DSA椎动脉造影阳性为病例组,阴性为对照组,分别计算4种检查方法的灵敏度、特异度和一致率。结果:DSA、椎动脉超声、TCD、MRA、CTA检查发现椎动脉异常率分别为50.00%(93/186)、30.81%(53/172)、49.42%(85/172)、15.10%(8/53)、40.00%(10/25)。以DSA椎动脉造影为参照标准,超声检查的灵敏度50.57%,特异度89.41%,一致率69.77%;TCD的灵敏度68.48%,特异度72.50%,一致率70.35%;MRA的灵敏度21.43%,特异度92.00%,一致率54.72%;CTA的灵敏度63.64%,特异度78.57%,一致率72.00%。结论:椎动脉超声、TCD、MRA、CTA4种方法根据患者综合情况,合理、联合应用,有助于全面客观地诊断伴有动脉硬化患者的椎动脉异常。对明确有脑血管疾病的患者进行潜在的颈椎手法推拿,需引起高度警惕,可能会出现椎动脉损伤而造成并发症。     

Analysis of risk factors for recurrence after the resection of sacral chordoma combined with embolization

Background contextAlthough several authors have already reported on the high local recurrence rate of sacral chordomas after surgical resection, there are no reports on the risk factors for recurrence after resection when combined with preoperative tumor-related blood vessel embolism by digital subtraction angiography (DSA) technique.PurposeTo investigate the factors related to the continuous disease-free survival time (CDFS) after the resection of sacral chordomas combined with embolization.Study design/settingRetrospective review of the signs, images, and immunohistochemical data of patients with sacral chordomas treated with an initial operation combined with transcatheter arterial embolization.Patient sampleTwenty-two patients with sacral chordomas received initial resection combined with transcatheter arterial embolization.Outcome measuresRecurrence, proliferating cell nuclear antigen (PCNA) expression, basic fibroblast growth factor (bFGF) expression, CDFS.MethodsAll cases were selected and followed for an average of 39.2 months. The roles of gender, age, tumor size, tumor location, surgical method, radiation therapy, PCNA expression, and bFGF expression in local recurrence were analyzed using the log-rank test.ResultsSacral chordomas recurred in eight of 22 cases. The CDFS was significantly greater in tumors located below S3 as compared with those above S3. When evaluating PCNA and bFGF expression levels, the CDFS was greater in low expressions rather than high expressions. It was determined that the surgical method used was of prognostic significance to the CDFS.ConclusionsHigher tumor location and higher expressions of PCNA and bFGF will lead to a shorter CDFS. Resecting the tumor as completely as possible will decrease the chances of local recurrence of sacral chordomas.     

Comparison of multislice computerized tomography angiography and digital subtraction angiography in the postoperative evaluation of patients with clipped aneurysms

OBJECT: In this study the accuracy of multislice computerized tomography (MSCT) angiography in the postoperative examination of clip-occluded intracranial aneurysms was compared with that of intraarterial digital subtraction (DS) angiography METHODS: Forty-nine consecutive patients with 60 clipped aneurysms (41 of which had ruptured) were studied with the aid of postoperative MSCT and DS angiography. Both types of radiological studies were reviewed independently by two observers to assess the quality of the images, the artifacts left by the clips, the completeness of aneurysm occlusion, the patency of the parent vessel, and the duration and cost of the examination. The quality of MSCT angiography was good in 42 patients (86%). Poor-quality MSCT angiograms (14%) were a result of the late acquisition of images in three patients and the presence of clip or motion artifacts in four. Occlusion of the aneurysm on good-quality MSCT angiograms was confirmed in all but two patients in whom a small (2-mm) remnant was confirmed on DS angiograms. In one patient, occlusion of a parent vessel was seen on DS angiograms but missed on MSCT angiograms. The sensitivity and specificity for detecting neck remnants on MSCT angiography were both 100%, and the sensitivity and specificity for evaluating vessel patency were 80 and 100%, respectively (95% confidence interval 29.2-100%). Interobserver agreements were 0.765 and 0.86, respectively. The mean duration of the examination was 13 minutes for MSCT angiography and 75 minutes for DS angiography (p < 0.05). Multislice CT angiography was highly cost effective (p < 0.01). CONCLUSIONS: Current-generation MSCT angiography is an accurate noninvasive tool used for assessment of clipped aneurysms in the anterior circulation. Its high sensitivity and low cost warrant its use for postoperative routine control examinations following clip placement on an aneurysm. Digital subtraction angiography must be performed if the interpretation of MSCT angiograms is doubtful or if the aneurysm is located in the posterior circulation.     

ROI-based image registration for digital subtraction radiography.

OBJECTIVE: We evaluated the influence of surrounding anatomical structures on the registration accuracy of a diagnostically important region, by varying the ROI (region of interest) window used in an automatic ROI-based digital subtraction method. STUDY DESIGN: Pairs of radiographs were taken at 2 molar regions using paralleling techniques of XCP devices (Rinn Co., Elgin, Ill) attached with and without a bite block. The global and local registration accuracies were measured by the RMS (root mean square) of subtraction images for various ROIs. RESULTS: No significant differences were found in global registration accuracies among various ROI sizes in all the paralleling techniques. The local registration accuracies decreased with extension of the ROI size. CONCLUSION: Registration using an ROI restricted to the anatomical region of diagnostic interest provides higher accuracy than using a larger ROI.     

Wall Imaging of Cerebral Aneurysms with a Modified Surface-Rendering Technique of Spiral CT

Summary ? Background. There has been no detailed documentation of the advantages of three-dimensional (3D) wall imaging of cerebral aneurysms. The usefulness of such endoscopic images obtained with modified spiral computed tomography angiography (CTA) was therefore examined in comparison with conventional spiral CTA and digital subtraction angiography (DSA).  Methods. Fifteen of 45 patients who underwent conventional spiral CTA in our department in the past 4 years, were further studied with a technical modification of surface-rendering reconstruction in spiral CT. Endoscopic images were obtained by regulating the lower and higher thresholds of spiral CT scans in processing. Digital subtraction angiography was also performed for 14 of the 15 patients. The 3D wall images of the cerebral aneurysms were assessed in comparison with findings from conventional CTA and DSA.  Findings. The true orifice of the aneurysms could be visualized with the endoscopic mode in all of the 15 cases. In paraclinoid aneurysms, particularly below the anterior clinoid process, the relationships to associated vessels and bone structures were more clearly disclosed with this mode. The endoscopic images of aneurysms with rigid clots or neighboring distended veins were not as adversely affected as conventional CTA. In 4 of the 15 the wall imaging precisely located the branches arising from the dome of aneurysms which DSA could not.  Interpretation. Wall imaging of complex or small cerebral aneurysms provided valuable information on their relationships to associated arteries and surrounding bony structures. The endoscopic mode, a simple modification of surface rendering, is easily available in commercial CT processing packages.     

Arterial diameters on catheter and computed tomographic angiography

BackgroundThe diagnosis of cerebral vasospasm is hampered by lack of an accurate, noninvasive test. Computed tomographic angiography (CTA) may be useful but the correlation between arterial diameters determined from catheter digital subtraction angiography (DSA) and CTA over a range of artery sizes would need to be determined to show this. The purpose of this study was to determine the correlation between artery diameters measured on DSA and multidetector CTA.MethodsTwo hundred forty artery diameters were measured in DSA and CTA from 46 patients who underwent both studies within 12 hours of each other. Axial cross section, maximum intensity projection, and volume-rendered images were measured and compared by linear correlation. Two independent readers measured CTA diameters to determine interobserver variability by linear correlation. Values also were categorized and compared by χ² and κ statistics. Analysis was repeated with unmeasurable arteries assigned a value of 0.ResultsThere were significant correlations between arterial diameters measured on DSA and those from CTA measured by any method (R² ranging from 0.45 to 0.76, P < .0001), although there was a tendency for the slope of this relationship to be less than 1, indicating underestimation of diameter of large and overestimation of diameter of small arteries with CTA. Computed tomographic angiography diameters also correlated significantly between the 2 reviewers with higher values often when unmeasureable arteries were assigned a value of 0 (κ = 0.23-0.55, P < .0001).ConclusionArterial diameters measured on multidetector CTA correlate well with those determined from DSA and should permit use of CTA for quantitative study of cerebral vasospasm and other conditions requiring accurate measurement of arterial diameters. The limitation of CTA remains the inability to measure some arteries due to artifact.