部分减影去骨技术在颅内动脉CT血管成像中的价值

近年来,CTA技术日益成熟,在血管病变诊断中发挥着重要的作用.由于颈椎及颅骨的影响,头部CTA去骨成像相当费时,难以显示颅底的血管全貌,以往采用2次扫描减影来解决,但笔者发现颅内动脉中仪颅底部分同颅骨关系密切,能否采用部分减影去骨即仪对颅底部分减影去骨进行颅内动脉成像?笔者应用部分减影去骨法进行颅内动脉CTA成像,对比部分减影去骨与减影及非减影去骨技术的优缺点,探讨部分减影去骨技术在颅内血管CTA中应用价值.     

双源CT双能量去骨技术在头颈部血管成像中的应用

目的：比较双能量去骨与减影去骨对头颈部血管CT成像（CTA）的差异,探讨头颈部双能量CT血管成像（DECTA）的应用价值。方法：50例患者行DECTA检查并行双能量去骨,对照组45例患者使用减影CTA检查并去骨,然后分别比较DECTA和减影CTA的图像质量、去骨所用时间及放射剂量,并观察DECTA上颈总动脉分叉处钙化的显示效果。结果：颅内动脉DECTA和减影CTA的图像质量差异无显著性意义（Z=0.790,P=0.430）,颈内动脉虹吸段和岩段DECTA图像质量优于减影CTA（虹吸段Z=-1.989,P=0.047;岩段Z=-2.014,P=0.044）,而减影CTA显示颈根部动脉优于DECTA（Z=3.900,P〈0.001）。同时DECTA减少约24.0%的放射剂量。DECTA上共有28例发现有血管性病变,所有病变显示清晰,其中10例并与DSA或外科手术对照具有良好的一致性。颈总动脉分叉处36个钙化灶中有8个钙化灶未在DECTA上显示。结论：DECTA显示头颈部血管总体良好,成功率高,且放射剂量明显减少,但对于颈根部动脉显示仍存在一定局限。     

16层螺旋CT头颈部血管减影成像技术初探

目的：探讨16层螺旋CT血管减影成像技术显示头颈部血管的能力及优势。方法：对20例行头颈部CT灌注的脑梗塞或（和）短暂性脑缺血发作（transient ischemicattack,TIA）患者进行CT血管减影成像检查。常规平扫后,选取基底节区进行静脉团注对比剂CT灌注（CTPeffusionimaging,CTP）扫描;然后根据CT灌注扫描获得动脉内对比剂峰值时间,用以设定平扫后动脉期的延迟时间,进而进行增强前后的同步薄层扫描,将增强前后（动脉期）的图像相减,即可获得动脉血管的原始图像,进行三维重建后显示动脉。结果：20例减影图像均能清晰显示颈内动脉颅内段、海绵窦段及颅内大动脉及其主要分支,其中15例无颅底骨质干扰,动脉显示良好,余5例因患者头部轻微运动,颅底骨质未能完全减去,但动脉尚能显示完整,不影响诊断。结论：16层螺旋CT血管减影成像,图像后处理简易省时,能提供类似MRA和DSA的血管图像,可广泛应用于临床,结合CTP资料,可有效预测颅内缺血性病变的发生。     

64层螺旋CT分别减影脑动脉混合脑动静脉和脑静脉血管成像在颅内自发性出血术前评估的价值

目的：探讨64层螺旋CT分别减影脑动脉、混合脑动静脉、脑静脉血管成像在自发性颅内出血术前评估价值。方法回顾分析同时行CT血管造影（CTA）和数字减影血管造影（DSA）检查的自发性颅内出血患者共215例。 CTA检查全部行64层螺旋CT平扫、增强动脉早期和静脉早期扫描,将动、静脉早期数据减去平扫数据分别重建动脉及混合动静脉,静脉早期数据减去动脉早期数据重建静脉。结果减影脑动脉、脑静脉血管图像去除了颅骨并且动脉、静脉无相互干扰,分别清晰显示动脉或静脉病变,混合脑动静脉则去除颅骨干扰且同时显示脑动静脉病变。215例颅内出血患者中14例CTA和DSA检查颅内均未见畸形血管,2例动脉瘤DSA发现而CTA未显示,3例动脉瘤CTA发现而DSA未显示。 CTA和DSA共同显示畸形血管196例,敏感性为99．9％,特异性为82．4％,其中动脉瘤179例,动静脉畸形9例,静脉瘤3例,烟雾病5例。结论64层螺旋CT分别减影脑动脉、混合脑动静脉、脑静脉血管成像在颅内出血检查,病变及周围结构显示清楚,对临床术前评估有较大意义,值得推广应用。     

双能量减影自动去骨技术在双源CT颈动脉成像中的临床应用

目的探讨双源CT双能量减影中自动去骨技术在颈动脉成像中的临床应用价值。方法对65例临床拟诊颈动脉狭窄的患者,行双源CT颈部血管成像,分析双能量减影自动去骨技术对颈动脉病变的显示,并评价图像质量。结果 65例中3例血管正常变异,33例未见明显病变,血管主干及其分支显示清楚。32例颈动脉粥样硬化,其中4例支架植入术后。双能量CTA对颈根段、颅外段及颅底段血管的满意显示率分别为67.2%、96.2%及66.2%;3个部位血管原始评分比较差异有统计学意义(P=0.000);进一步两两比较,颈根段和颅底段血管的评分差异无统计学意义(P=0.181)。结论双源CT双能量减影成像是一种快速、简便、无创性检查方法,其整体去骨效果较好,血管显示效果最好者是颈动脉颅外段(颈总动脉和颈内动脉颅外段)。     

64层螺旋CT数字减影术对头颈部动脉成像应用研究

目的:探讨64层螺旋CT数字减影技术对头颈部动脉成像的优势。方法:对25例怀疑头颈部血管病变患者行64层螺旋CT血管减影成像检查,用特殊头部固定装置固定头颅,先行平扫,然后以相同的扫描参数行增强扫描,将增强前后图像送至工作站进行减影,利用inspace从减影的图像中提取动脉,进行血管重组,其中15例同时行常规CTA检查,8例行DSA检查,比较减影CTA与常规CTA的成像速度、图像质量,并与DSA成像比较。结果:25例均能显示颈总动脉、颈内动脉、椎动脉及主要分支,其中17例颈椎及颅底骨质完全减去,血管显示良好,8例因检查时头部轻微动或做吞咽动作而造成部分颈椎骨及颅底骨未完全减去,但动脉仍能显示,减影CTA平均成像时间4.3min,常规CTA平均成像时间24.3min,2种成像技术比较,颈部动脉图像质量无明显差别,减影CTA对颅内动脉主干及更多分支的显示优于常规CTA,减影CTA与8例DSA比较图像完全相同。结论:64层螺旋CT血管减影技术省时省力、便捷灵活、图像质量好,值得在临床推广。     

颅颈联合减影CT血管成像对脑缺血的诊断价值

目的 探讨减影CTA在缺血性脑血管病诊断中的应用价值.方法 83例临床拟诊短暂性脑缺血发作(TIA)或脑梗死患者行颅颈部CT血管成像检查,在同一序列依次进行平扫和增强扫描,增强延迟16～20整数秒,重建层 厚0.625 mm,间隔0.45 mm,通过Image Combination V7.01软件自动处理获得减影图像.由1名有经验的操作者间隔30 d以上对同一病例常规CTA和减影CTA图像分别进行去骨处理并记录消耗时间.由2名资深放射科医师以商讨形式对去骨效果、血管边缘清晰度评级,血管狭窄程度按NASCET标准分级.结果 2组去骨时间有统计学差异,减影CTA时间为(16.0±0.23)min vs (19.9±0.18)min(t=19.10,P<0.001);减影CTA去骨效果优于常规CTA(χ2=12.6,P=0.006),虽然减影与常规CTA对血管狭窄程度分级差异没有统计学意义(χ2=0.06,P=0.972),但减影CTA血管边缘清晰度不如常规CTA(χ2=15.0,P=0.002).结论 减影CTA去骨快,血管连续性好,能整体显示血管走行、狭窄部位及程度,但血管边缘清晰度稍差,且不适用于斑块性质准确评估.     

64排螺旋CT减影血管成像在头部烟雾病诊断中的应用

目的探讨64排螺旋CT减影血管成像技术在烟雾病诊断中的临床价值。方法回顾分析在我院行减影脑血管成像烟雾病患者,共18例。对整个头部平扫、增强动脉早期和静脉早期扫描获得未减影数据,将动脉早期数据减去平扫数据获得减影动脉期数据,静脉早期数据减去动脉早期数据获得减影静脉期数据。采用容积再现(VR)、最大密度投影(MIP)重建减影血管图像。结果减影图像去除了动脉、静脉相互的及颅骨的干扰,对脑动、静脉解剖结构显示清楚,特别是对烟雾病异常颈内动脉和脑底血管网显示。本组显示脑底异常血管网占100%;双侧颈内动脉狭窄占61%,左侧颈内动脉狭窄占17%,右侧颈内动脉狭窄占22%;双侧大脑中动脉狭窄占39%(其中1例左侧大脑中动脉闭塞),右侧大脑中动脉狭窄占17%;双侧大脑前动脉狭窄占39%(其中1例双侧大脑前动脉闭塞),无单侧大脑前动脉狭窄;合并脑动脉瘤占17%;全部脑静脉未见异常。结论 64排螺旋CT智能跟踪扫描减影技术能清楚分别显示脑动脉和脑静脉,在显示颅内动脉血管畸形时可排除脑静脉畸形,对颅内烟雾病分析评价有较大临床价值。     

64层螺旋CT减影血管成像诊断脑动静脉畸形的价值

目的：探讨64层螺旋CT减影血管成像诊断脑动静脉畸形（AVM）的价值。材料和方法：26例脑AVM患者,均经64层螺旋CT平扫、增强动脉期和静脉期扫描。将动脉期数据减去平扫数据获得减影动脉期数据,静脉期数据减去动脉期数据获得减影静脉期数据,静脉期数据减去平扫数据获得减影混合动静脉期数据。采用容积再现（VR）、最大密度投影（MIP）重建脑血管图像。结果：本组病例减影脑血管图像均去除了颅骨的干扰,清楚显示大小不等的畸形血管巢及供血动脉和引流静脉。畸形血管巢位于颞叶7例,顶叶5例,额叶5例、枕叶6例和小脑半球3例。发现供血动脉39支,其中单支供血动脉15例,多支供血动脉9例;引流静脉33支,单支引流10例,多支引流16例。结论：64层螺旋CT减影血管成像可以去除颅骨干扰,显示AVM的供血动脉、畸形血管巢和引流静脉,为临床治疗方案的制定及术后随访提供可靠的依据。     

脑血管成像中减影CTA与常规CTA去骨技术的对照

目的探讨减影CTA去骨技术和常规CTA去骨技术在脑血管成像中重建时间及图像质量的差异。方法回顾性分析30例行脑血管减影CTA和常规CTA检查的患者的资料,后处理重建均用最大密度投影技术(MIP)和容积再现技术(VR),以评价减影CTA和常规CTA图像质量及重建时间。结果减影CTA图像质量优于常规CTA图像质量,且重建时间短于常规CTA。显示血管狭窄及颅底动脉瘤优于常规CTA。结论减影CTA去骨技术用于脑血管成像质量优良,重建血管迅速,显示血管狭窄及颅底动脉瘤优于常规CTA。减影CTA结合曲面重建(CPR)既能显示管腔又能有效的显示动脉管壁情况,弥补了DSA的不足。     

双能量CT头颈部血管减影成像的效果评价及临床应用

目的：评价双能量CT在头颈部血管减影中自动去骨的效果及其临床应用价值。方法：52例临床怀疑头颈部血管疾病的患者随机分为2组,分别进行双能量CT血管减影成像和常规CT血管减影成像,分别用双能量处理软件和Neuro-DSA软件自动完成去骨,采用容积重建（VR）、最大密度投影（MIP）、多平面重组（MPR）等多种后处理方法,由两位经验丰富的放射科医生采用双盲法评价两种减影方法的去骨效果,并进行比较;同时结合非减影数据,观察血管病变情况。结果：双能量CT血管减影成像和常规CT血管减影成像的容积CT剂量指数（CTDIvol）分别为（20.5635±0.00977）mGy和（25.5746±0.55827）mGy,两者有显著性差异。两种方法对于颈动脉、椎动脉及整体头颈部血管的满意显示率分别为87.8%,68.0%,83.0%和93.5%,91.8%,92.6%,其中对于颈动脉的显示无明显差异,但双能量CT血管减影对部分椎动脉的减影效果较常规CT血管减影差,主要集中在椎动脉近颅底的部分。另外,双能量CT血管减影成像还发现了多处血管病变,临床符合率为100%。结论：相比头颈部常规CT血管减影,双能量CT血管减影辐射剂量更低,能够有效的去除绝大多数骨骼,为头颈部血管疾病的诊断提供了一种新的无创性检查方法。     

Bone-subtraction CT angiography for the evaluation of intracranial aneurysms

PURPOSE: CT angiography (CTA) has been established for detection and therapy planning of intracranial aneurysms. The analysis of aneurysms at the level of the skull base, however, remains difficult because bone prevents a free view. We report initial clinical results of an approach for automatic bone elimination from CTA data. MATERIAL AND METHODS: Before the bone-removal process 2 datasets are acquired: nonenhanced spiral CT with reduced dose and contrast-enhanced CTA. The software automatically registers the nonenhanced data onto the CTA data and selectively removes bone. Vascular structures, as well as brain tissue, remain visible. In this study, we investigated 27 patients with 29 aneurysms, 13 of which were located at the skull base. 3D volume-rendered images with and without bone removal were reviewed and compared with digital subtraction angiography by 2 radiologists in consensus. RESULTS: All supraclinoidal aneurysms were detected on 3D volume-rendered images of both CTA and bone-subtraction CT angiography (BSCTA). Four intracavernous and 3 paraclinoid aneurysms of the internal carotid artery were not visible or were only partially visible on conventional 3D CTA, whereas they could be optimally visualized with BSCTA. Bone removal was successful in all patients; the average additional time for postprocessing was 6.2 minutes. In 7 patients (26%), perfect bone removal without any artifacts was achieved. In most patients, some bone remnants were still present, though it did not disturb the 3D visualization of vascular structures. CONCLUSION: BSCTA allows robust and fast selective elimination of bony structures, thus ascertaining a better analysis of arteries at the level of the skull base. This is useful for both detection and therapy planning of intracranial aneurysms.     

颅脑创伤血管痉挛的CT血管造影评价

目的 :探讨CT血管造影 (CTA)在评价颅脑外伤性血管痉挛中的应用。材料和方法 :对 19例颅脑外伤患者和 10例对照组患者采用多层螺旋CT增强扫描获得原始图像 ,用最大强度投影 (MIP)和容积显示 (VR)技术进行三维重建CTA观察和分析。结果 :所有患者均成功获得良好的CTA图像 ,9例患者发现脑血管痉挛 16处 ,其中 13处出现在大脑中动脉 ,并大多呈串珠样改变。VR显示血管改变最佳 ,可充分显示血管痉挛 ;结合横断面图像可全面评价脑创伤情况。结论 :外伤后脑血管痉挛大多呈串珠样改变 ,CTA VR可充分显示血管痉挛 ,有助于研究外伤后脑血管的变化。     

CT angiography in the rapid triage of patients with hyperacute stroke to intraarterial thrombolysis: accuracy in the detection of large vessel thrombus

PURPOSE: The purpose of this work was to evaluate the accuracy of CT angiography (CTA) for the detection of large vessel intracranial thrombus in clinically suspected hyperacute (<6 h) stroke patients. METHOD: Forty-four consecutive intraarterial thrombolysis candidates underwent noncontrast CT followed immediately by CTA. Axial source and two-dimensional collapsed maximum intensity projection reformatted CTA images were rated for the presence or absence of large vessel occlusion. Five hundred seventy-two circle-of-Willis vessels were reviewed; arteriographic correlation was available for 224 of these. RESULTS: Sensitivity and specificity for the detection of large vessel occlusion were 98.4 and 98.1%; accuracy, calculated using receiver operating characteristic analysis, was 99%. Mean time for acquisition, reconstruction, and analysis of CTA images was approximately 15 min. CONCLUSION: CTA is highly accurate for the detection and exclusion of large vessel intracranial occlusion and may therefore be valuable in the rapid triage of hyperacute stroke patients to intraarterial thrombolytic treatment.     

64层螺旋CT脑血管造影在颅内动脉瘤诊断中的应用

目的:与DSA相对照,探讨64层螺旋CT脑血管造影在颅内动脉瘤中的诊断价值。方法:对29例临床怀疑颅内动脉瘤的患者行64层螺旋CT脑血管造影(CTA)和DSA检查,使用GE64层Lightspeed VCT获得原始图像,所有病例均采用多层面重建(multiplanar reconstruction,MPR)、容积再现(volume rendering,VR)、薄层块最大密度投影(thin-slab maximumintensity projectjon,TS MIP)。后处理图像及DSA图像由2位放射科医生共同评估。结果:29例患者中,DSA证实25例共27个动脉瘤,其中2例为2个动脉瘤。与DSA结果相对照,CTA共检出25例26个动脉瘤,漏诊了1个颈出动脉瘤。CTA清晰显示了动脉瘤的形态、大小及载瘤动脉,3例动脉瘤瘤颈DSA未显示,CTA显示了全部动脉瘤的瘤颈。结论:64层CTA在颅内动脉瘤的诊断中具有极高价值,特别在显示动脉瘤瘤颈方面具有独特的优势,对临床治疗具有指导意义。     

以脑CT灌注的峰值时间作为脑CTA扫描延时的应用

目的应用CT脑灌注方法准确预测脑动脉环CTA检查延迟时间。方法14例病人均有典型的短暂性脑缺血(TIA)发作史或缺血性脑血管病史,先对其进行CT脑灌注扫描,通过测量大脑前动脉CT值达峰时间与开始扫描时间的差值指导脑动脉环CTA的延迟时间。结果应用此方法指导脑CTA检查,动脉环显示均较满意。结论先行CT脑灌注成像,根据测量值预测脑CTA检查延迟时间是保障CTA检查成功的一种较好的方法。     

脑血管腔内碘对比剂浓度对脑血管CT血管成像图像质量的影响

目的探讨脑血管腔内不同碘对比剂浓度对脑血管 CT 血管成像(CTA)图像质量的影响,以确定使血管显示最佳的 CT 值阈值.资料与方法连续测量60例 CTA 病例左侧颈内动脉入颅前段(LEICA)、左侧大脑中动脉 M1段(LM1)、左侧大脑前动脉A2段(LA2)、左侧椎动脉颅内段(LIVA)、基底动脉(BA)血管腔内 CT 值,头颈部 CTA 加测左侧颈外动脉(LECA)CT 值,观察段血管发生病变时测量对侧,评价常规与减影 CTA 血管重建图像质量.结果常规与减影 CTA 图像中,优、良、差组患者年龄差异无统计学意义(P>0.05).LEICA、BA、LIVA 及 LECA 常规与减影 CTA 图像以及 LM1常规 CTA 图像优、良组与差组 CT 值差异有统计学意义(P<0.017),优组与良组差异无统计学意义(P>0.017).LM1减影 CTA 图像及 LA2常规与减影 CTA 图像优、良、差组两两比较,各组间 CT 值差异均有统计学意义(P<0.017).LM1减影 CTA 图像及 LA2常规与减影 CTA 图像中最佳图像显示的 CT 值阈值分别为(506±89)Hu、(460±67)Hu、(436±60)Hu.结论随着脑血管腔内碘对比剂浓度增高,血管强化程度增强,有利于提高脑血管 CTA 的图像质量.     

Value of automatic bone subtraction in cranial CT angiography: comparison of bone-subtracted vs. standard CT angiography in 100 patients

Non-contrast-enhanced cranial computed tomography (NECT) and CT angiography (CTA) are the most frequently used modalities in the triage of patients with acute ischemic and hemorrhagic stroke. CTA bone removal can improve the delineation of vasculature closely adjacent to bony structures, which is sometimes limited in standard CTA. The aim of this study was the evaluation of the clinical benefit of bone subtraction (BS) regarding delineation of cerebral vasculature, reading time and depiction of vascular pathologies compared to standard CTA without BS. A total of 100 patients who underwent NECT and supraaortic CTA on a 64-slice CT system were retrospectively included in the study. Bone removal was performed by subtraction of the NECT data from the CTA data using a dedicated workstation. Standard and BS CTA of each patient was reviewed for delineation of cerebral vasculature (grading scale from 1 = “excellent delineation” to 10 = “hardly any delineation”), reading time and depiction of vascular pathologies (standardized catalog) by two blinded readers. For BS data sets, the quality of BS was rated by a combination of the criteria complete bone removal, depiction of vascular structures and sufficient quality for diagnostic evaluation. The use of BS significantly reduced reading time from 4.60 min to 3.49 min (p < 0.001). Performing BS, the quality of vascular delineation of the cerebral arteries, cerebral veins and cavernous segment of the ICA increased significantly as compared to standard CTA (1.70 vs. 2.70; 2.60 vs. 4.12; 2.35 vs. 4.40, all p < 0.001). Consensus reading showed 41 pathologies in 35 patients. Diagnosis was missed or wrong overall in 15 cases, with 3 missed aneurysms (CTA: 2 vs. BS: 1), 8 wrong stenotic findings (CTA: 3 vs. BS: 5) and 4 missed partial thromboses (CTA: 2 vs. BS: 2). Performing BS in supraaortic CTA for the evaluation of cerebral vasculature reduces reading time and improves delineation of vessels. Diagnostic accuracy in general is not improved by BS, as the diagnostic accuracy of stenotic vessel alterations is reduced by potential truncation artifacts, but the detection rate of cerebral aneurysms slightly increases.     

Dual-energy direct bone removal CT angiography for evaluation of intracranial aneurysm or stenosis: comparison with conventional digital subtraction angiography

Dual-energy CT can be applied for bone elimination in cerebral CT angiography (CTA). The aim of this study was to compare the results of dual-energy direct bone removal CTA (DE-BR-CTA) with those of digital subtraction angiography (DSA). Twelve patients with intracranial aneurysms and/or ICA stenosis underwent a dual-source CT in dual-energy mode. Post-processing software selectively removed bone structures using the two energy data sets. Three-dimensional images with and without bone removal were reviewed and compared to DSA. Dual-energy bone removal was successful in all patients. For 10 patients, bone removal was good and CTA maximum-intensity projection (MIP) images could be used for vessel evaluation. For two patients, bone removal was moderate with some bone remnants, but this did not inhibit the three-dimensional visualization. Three aneurysms adjacent to the skull base were only partially visible in conventional CTA but were fully visible in DE-BR-CTA. In five patients with ICA stenosis, DE-BR-CTA revealed the stenotic lesions on the MIP images. The correlation between DSA and DE-BR-CTA was good (R ²=0.822), but DE-BR-CTA led to an overestimation of stenosis. DE-BR-CTA was able to eliminate bone structure using only a single CT data acquisition and is useful to evaluate intracranial aneurysms and stenosis.