多层螺旋CT肝脏双期血管成像及临床应用

目的　探讨多层螺旋CT(MSCT)肝脏多期扫描 ,肝动脉和门静脉双期血管成像的可能性及其临床应用。资料与方法　 14例正常者及 15例肝硬化患者 (包括 6例肝癌 )行MSCT多期扫描 ,准直 2 .5mm ,pitch 5 ,每期扫描时间约为 6～ 9s。分别于肝动脉期和门静脉期进行血管三维成像 ,重建方式为容积再现技术 (VR) ,最大密度投影(MIP) ,表面遮盖法重建技术 (SSD)。统计 3种成像方法对胃十二指肠上动脉 ,肝固有动脉 ,肝左、右动脉的显示率 ,并对门静脉显示情况进行评分。结果　肝动脉期血管成像可清晰显示扫描范围内的腹主动脉 ,腹腔干血管及其分支 ,VR、MIP及SSD对胃十二指肠动脉 ,肝固有动脉 ,肝左、右动脉的总显示率分别为 85 .3% ,85 .3% ,6 6 .4 %。门静脉期血管成像能清晰显示门静脉系统情况 ,正常人门静脉可显示 6级以上 ,VR及MIP优于SSD(P <0 .0 5 ) ,VR立体感强于MIP。结论　MSCT肝脏多期扫描 ,双期血管成像是了解肝脏供血动脉和门静脉系统情况的无创性检查方法 ,以VR血管成像最佳 ,可为临床提供更多的有关肝动脉和门静脉方面的信息     

MSCTA在肝移植中的应用价值

目的:探讨多层螺旋CT血管造影(MSCTA)在肝移植中的临床应用价值.方法:病例组选择32例肝癌和肝硬化在移植前后行多层螺旋CT(MSCT)多期扫描,包括肝癌10例(肝癌组)、22例肝硬化CTP分级C级(肝硬化组).分别于肝动脉期和门脉期进行血管3D成像,重建方法包括MPR、MIP、VR.于MIP图像上分别测量腹腔动脉 (CA)、胃左动脉(LGA)、肝总动脉(CHA)、肝固有动脉(PHA)、肠系膜上动脉(SMA)及门静脉(PV)、脾静脉(SV)、肠系膜上静脉(SMV) 的管径.数据用SPSS10.0处理,资料用均数±标准差(±S)表示,两组均数比较采用t检验;多组间的比较用单因素方差分析(ANOVA),两两比较用q检验.P＜0.05有统计学意义.结果:肝动脉期血管成像可清晰显示扫描范围内的腹主动脉、腹腔干,胃十二指肠动脉,肝固有动脉,肝左、右动脉及其分支;门静脉期血管成像能清晰显示门静脉系统情况.病例组32例中有21例肝动脉及其分支解剖正常,MIP及VR所显示的正常解剖肝动脉无明显差异.病例组中11例、正常对照组6例显示肝动脉分支异常.于MIP像上能准确测量腹腔大动脉血管管径及门静脉、肠系膜上静脉及脾静脉的管径,对照组与肝硬化组及肝癌组动脉管径无统计学差异,而门脉高压患者门静脉主干、肠系膜上静脉及脾静脉的管径与对照组相比,差异有统计学意义(P<0.05).结论:肝脏MSCTA能准确显示血管解剖、变异及病变情况,对静脉、变异的肝动脉进行管径测量,掌握个体化肝脏血管变异及其血管大小信息,为手术方式、制订术中血管吻合方案提供客观依据,并监测术后血管并发症.     

多层螺旋CT血管成像诊断肝脏病的价值

目的:探讨多层螺旋CT血管成像诊断肝脏疾病的应用价值.材料和方法:应用GELightSpeedQX/i4层螺旋CT机,对152例患者行肝脏CT3时相增强扫描,扫描后对原始数据行三维薄建重建,分析其结果.结果:152例中,原发性肝细胞癌41例、肝海绵状血管瘤52例、肝脏囊肿15例、脂肪肝8例、肝脓肿5例、肝脏转移瘤8例、胆囊癌3例、胆管癌4例和正常16例.动脉期均成功显示腹主动脉及其主要分支如腹腔干,肾动脉,肠系膜动脉等.143例可清晰显示肝总动脉与脾动脉,胃左动脉显示清晰者123例(VR像显示108例,MPR像显示123例),发现异常的分支16例.结论:多层螺旋CT血管成像在肝脏CT扫描中能直观地显示病变及周围血管的关系,对外科手术及介入治疗提供参考信息.     

多层螺旋CT肝脏兼容性血管造影在肝癌介入治疗中的应用价值

目的 探讨多层螺旋CT（MSCT）肝脏兼容性血管造影在肝癌介入治疗中的应用价值。方法 MSCT肝癌CT检查患者45例,于动脉期22s、门静脉期55s行肝脏双期增强扫描,采用MPVR、MIP、VR、SSD重建技术行肝动脉、门静脉兼容性血管成像。其中22例作了肝动脉DSA造影及介入治疗。结果 动脉期肝动脉血管造影（SCTA）显示肿瘤血管31例,肿瘤染色17例,动-门脉分流（APS）9例。门脉期门静脉造影（SCTP）检出肿瘤对门静脉的侵犯25例,门静脉癌栓16例。MSCT显示的肿瘤血管、肿瘤染色、供血动脉的来源分布、APS及门静脉癌栓与DSA图像基本一致。MPVR、VR有利于检出肝癌供血动脉、肿瘤血管、肿瘤染色、APS及门静脉癌栓。结论 MSCT肝脏兼容性SCTA、SCTP血管造影,可为临床及肝癌介入治疗方案的制定提供更多信息。     

16层螺旋CT上腹部增强扫描显示肝动脉系的价值

目的探讨出16层螺旋CT上腹部常规增强扫描对肝动脉系的显示能力,以及MSCTA后处理技术的合理应用. 材料和方法回顾性分析50例肝脏16层螺旋CT双期增强的动脉期MSCTA影像(肝细胞癌36例和肝海绵状血管瘤14例),评估其对肝动脉系的显示能力;对比分析MIP、VRT、SSD后处理技术的MSCTA所见. 结果MIP、VRT、SSD均可清楚显示腹腔干及其主要分支(显示率均为100%);VRT、MIP可显示肝固有动脉和肝左、右动脉(显示率100%);肝动脉左、右支及其Ⅱ、Ⅲ级分支以薄层MIP显示最佳(显示率均为100%);薄层MIP可显示血管与病灶的关系(83个病灶,79个显示,显示率95%);VRT在显示血管形态和走行方面优于其他后处理方法,可提示血管与病灶的关系;SSD不作为MSCTA成像的首选方法. 结论16层螺旋CT上腹部常规增强扫描,利用3D后处理技术,可清楚显示肝固有动脉、肝左、右动脉、及其细小分支,准确评估血管变异及病灶与血管的关系;后处理方法以VRT结合薄层MIP最佳.     

多层螺旋CT肝静脉成像后处理技术

目的：探讨多层螺旋CT肝静脉成像技术及后处理方法。方法：20例患者行肝脏动脉期、门静脉期及肝静脉期3期扫描,肝静脉期图像分别行1mm及2mm层厚重建,图像重叠60%,分别对两组薄层图像行最大密度投影（MIP）、多平面重组（MPR）、遮蔽表面显示（SSD）和容积再现（VR）,比较各种后处理技术显示肝静脉的优缺点。结果：所有病例均清晰显示第二肝门的肝左、肝中及肝右静脉,20例中有18例显示第三肝门静脉属支,另2例在第二肝门以下未见明显肝静脉引流入下腔静脉。1mm重建层厚较2mm重建层厚对微小肝静脉的显示更好,图像质量好。4种后处理方法中轴面薄层MIP显示的引流静脉数目最多,冠状面MPR对第二肝门及第三肝门的解剖关系显示最好。VR及SSD对门静脉系、第二肝门及第三肝门各静脉属支立体结构关系显示最好。结论：多层螺旋CT肝静脉成像可显示主要肝静脉,1mm重建层厚,60%影像重叠后的重建图像质量较好,各种重组技术相结合可清晰、立体显示门静脉系、第二肝门及第三肝门的结构。     

多层螺旋CT三维血管成像对原发性肝癌重复介入治疗的指导价值

目的:探讨多层螺旋CT血管造影(MSCTA)及三维重建对原发性肝癌重复介入治疗的指导价值.方法:对40例原发性肝癌患者,再次进行介入治疗时先行MSCTA检查,并用最大密度投影(MIP)、容积成像(VR)、多平面重建(MPR)技术对血管进行三维重建.结果:40例原发性肝癌患者共进行MSCTA检查及三维重建76次,共发现肝动脉解剖变异8例,栓塞治疗后肿瘤侧支循环形成28例,肝动脉闭塞2例.MSCTA显示腹腔动脉及肝动脉分支的三维结构以及介入治疗后侧支循环形成、来源方面优于DSA.结论:MSCTA及三维重建能直观、清晰的显示肿瘤病灶的供血血管立体解剖图像,对再次介入治疗制定手术方案具有重要指导意义.     

多层螺旋CT对肝移植受体手术前后评估

目的探讨多层螺旋CT血管造影（MSCTA）对原位肝移植受体手术前后的评估. 资料与方法对14例临床拟行肝移植受体进行MSCT多期增强扫描,并行2D、3D血管重建,观察肝脏、血管情况.5例行原位肝移植手术患者的MSCTA图像与手术对照分析. 结果 14例患者的肝脏病变及肝动脉和门静脉系血管结构清晰显示,其中肝硬化6例,肝硬化合并肝癌5例,Budd-Chiari综合征1例,Budd-Chiari综合征合并肝硬化1例,Budd-Chiari综合征合并小肝癌1例. 肝动脉解剖走行常见型11例,变异3例,腹腔干狭窄2例,肝动脉狭窄1例,脾动脉瘤1例.显示门静脉系血栓5例,门脉高压侧支循环形成6例;胆管结石3例.5例肝移植受体术前门脉癌栓1例,门脉高压侧支循环形成3例,术后未发现并发症. 结论 MSCTA对肝移植受体术前术后提供更多准确的信息,具有很好的应用前景.     

64层螺旋CT在肝癌治疗中的临床应用价值

目的:探讨64层螺旋CT三维成像技术在肝癌治疗中的临床应用。方法:采用64层螺旋CT三维成像检查对97例肝癌患者行肝脏增强后的动脉期及门静脉期扫描,重组方法为最大密度投影(MIP)、多平面重建(MPR)、容积再现技术(VR),并与术中探查结果及数字减影血管造影(DSA)做对照观察。结果:97例中癌肿未侵犯邻近组织、血管者69例,肿瘤压迫邻近血管者19例,肝动脉变异38例(39%),肝动脉-门静脉瘘(HAPF)16例,门静脉癌栓11例,合并肝硬化者71例,门静脉海绵样变性2例,除30例患者行TACE治疗外,其余67例均行手术治疗,与术中探查结果相一致者63例,正确率95.5%。在30例同期行DSA检查的肝癌患者中,3级以下肝动脉分支与DSA无显著差异,对4级以上分支的显示不如DSA,在供血动脉、肿瘤血管及血管变异的显示上与DSA完全一致。结论:64层螺旋CT三维成像检查可以很好的显示肿瘤的大小、形态、累及范围,特别能精确判断肿瘤与肝脏血管的关系,充分了解肝脏血管变异情况,对指导外科及介入治疗具有重要价值。     

MSCT血管成像对肝脏遗传性出血性毛细血管扩张症的诊断

目的 探讨多层螺旋CT血管成像技术对肝脏遗传性出血性毛细血管扩张症的诊断.方法对5例经多层CT血管成像检查诊断为肝脏遗传性出血性毛细血管扩张症的病例进行回顾性分析.对所有病例行容积再现(VR)、最大密度投影(MIP)、薄层MIP以及多平面重组(MPR).结果 5例CT增强扫描轴位仅能显示肝周围及肝内血管结构的扭曲、扩张改变.血管成像可清晰显示供血动脉血管的迂曲扩张、扭曲;肝窦明显扩张、早显;肝静脉早显; 5例门静脉均未见早显,显示尚正常.不同的重组方法适合显示不同血管情况.结论 多层螺旋CTA较轴位图像可以清晰详细地显示肝脏遗传性出血性毛细血管扩张症的血管改变.     

MSCT肝脏血管成像对肝脏移植受体的临床应用价值

目的:探讨64层螺旋CT腹腔干、门静脉及下腔静脉成像技术对肝脏移植受体血管结构评价的临床价值方法:对30例拟行肝脏移植手术的患者行增强后动脉期、门静脉期及下腔静脉期扫描。对每一例病例均行腹腔干、门静脉及下腔静脉三维重建及二维重组并与轴位图像结合分析患者血管情况。根据受体肝脏血管情况筛选出其中24例适宜手术的患者,初步拟定手术方案行肝移植手术,并在手术后与肝移植手术医师的术中探查结果相比较,探讨术前CT血管重建的准确性。结果:腹腔干成像可发现3例腹腔干狭窄,1例腹腔干动脉瘤,2例脾动脉瘤,2例肝脏主要供血动脉直径<3mm,10例肝动脉走行变异。门静脉成像发现2例肝门静脉海绵样变;12例肝门静脉栓塞,其中5例肝内门静脉栓塞,5例肝外门静脉主干栓塞(其中3例合并肠系膜上静脉栓塞);2例肝内门静脉及肝外门静脉主干均有栓塞。2例肝门静脉海绵样变及3例肝外门静脉主干及肠系膜上静脉广泛栓塞的患者因不适宜手术而未能行肝移植手术。下腔静脉成像发现2例下腔静脉癌栓,其中1例栓子接近右心房入口处,不适宜手术未能行肝移植手术;2例下腔静脉肝后段狭窄。30例中24例均成功行肝移植手术,术中所见与CT血管成像所见完全相符合。结论:64层螺旋CT血管成像适合用来全面准确评价拟行肝脏移植的受体的血管状态,对筛选适宜手术的病例并协助手术方案的制定有重要价值。     

多层螺旋CT对门静脉海绵样变的诊断价值

目的:分析门静脉海绵样变(CTPV)的多层螺旋CT(MSCT)表现和特征,探讨MSCT对该病的诊断价值.方法:使用16排MSCT对30例CTPV患者,行上腹部CT平扫、动态增强扫描,采用多平面重组(MPR)、最大密度投影(MIP)、容积再现 (VR)等图像后处理技术显示异常的门静脉及侧枝血管情况.结果:CTPV的MSCT平扫示门静脉结构不清,肝门区可见多发的结节状软组织影.增强扫描示动脉期10例有肝实质灌注异常;门静脉期18例患者门静脉主干和(或)左右分支增粗,内可见充盈缺损,4例门静脉显示不清;8例门静脉主干和(或)左右分支在正常范围内;1例门静脉主干变细.胆管周围静脉丛(100%)、胆囊静脉(60%)及胃左静脉(23.3%)呈点状、簇状扩张.MPR、MIP、VR可直观地显示各曲张血管的走行及曲张程度.结论:MSCT及图像后处理系统对CTPV诊断具有重要价值,门静脉栓塞及其周围纡曲扩张的侧枝静脉为其特征性表现.     

多层螺旋CT对胫骨平台骨折的诊断价值

目的:评价MSCT在胫骨平台骨折的分类及制定合理的治疗方案方面的价值。方法:对24例常规X线平片或临床诊断为胫骨平台骨折的患者进行MSCT扫描,并对图像进行MPR、SSD和VR重建,对骨折的部位、范围、碎骨片的数量或骨折程度、胫骨平台受累情况、手术入路、骨质疏松程度及骨组织的缺损等做出评价。骨折的分型根据Swiss AO-ASIF法。结果:24例患者中有19例进行了手术治疗,术中所见与轴位MSCT和MPR、SSD及VR重建图像综合做出的诊断一致。结论:MSCT及其MPR、SSD、VR重建技术对于胫骨平台的骨折分型及术前评价有重要意义。     

多层螺旋CT在肝癌肝动脉化疗栓塞中的价值

目的 评价多层螺旋CT（MSCT）在肝癌（HCC）肝动脉化疗栓塞中的价值。方法 对54例肝癌患者分别行MSCT和DSA检查，比较病灶、合并症的显示情况和肿瘤的供血来源，MSCT观察腹腔动脉的解剖和走行应用三维容积再现（VRT）、最大信号强度投影（MIP）或多平面重组（MPR）技术。其中，12例进行了CT血管造影（CTA）检查。结果 54例肝癌患者MSCT发现病灶225个，门静脉瘤栓10例，动静脉瘘14例；DSA发现病灶216个，门静脉瘤栓形成8例，动静脉瘘18例；MSCT和DSA二者比较，MSCT对肿瘤的数目的显示率略高于DSA，但差异无统计学意义（P〉0．05）；MSCT能够显示腹腔动脉及其主要分支的三维结构，优于后前位DSA，观察与腹主动脉夹角较DSA更方便；MSCT发现肝动脉起源变异5例，与DSA完全符合。结论 MSCT对于肝癌肝动脉化疗栓塞有重要指导意义，选择最佳延迟扫描时间是显示病灶和血管的关键。     

Evaluation of the hepatic artery in potential donors for living donor liver transplantation by computed tomography angiography using multidetector-row computed tomography: comparison of volume rendering and maximum intensity projection techniques

PURPOSE: To compare the volume rendering (VR) and maximum intensity projection (MIP) computed tomography angiography (CTA) techniques using multidetector-row CT for hepatic artery evaluation of potential donors for living donor liver transplantation (LDLT). METHOD: Over a 9-month period, CTA using multidetector-row CT and conventional angiography was performed in 62 consecutive potential donors for LDLT. Acquisition of arterial phase scans was initiated within 5 seconds after reaching enhancement of the descending aorta up to 70 HU as measured by a bolus-tracking technique (collimation = 1.25 mm, table speed = 7.5 mm, reconstruction interval = 0.625 mm). Postprocessing was performed on a commercially available workstation. Computed tomography angiography images of the hepatic artery were made using the VR and MIP techniques. A total of 10 to 30 images of various planes were generated to reveal the origins and branching patterns of hepatic arteries. With a 2-week interval, two reviewers separately evaluated CTA using VR and MIP techniques, specifically evaluating anatomic variations and hepatic arterial conspicuity. The results of conventional angiography were considered to represent the gold standard. The difference in postprocessing time between the two techniques was statistically analyzed by the Student t test, and the differences in arterial conspicuity and in the identified number of the hepatic artery to segment IV of the liver were analyzed by the chi2 test. RESULTS: Two CT examinations (3%) were technically inadequate for generating CTA because of respiratory motion artifact. The average times for postprocessing of VR and MIP images were 8.1 +/- 3.8 minutes and 5.0 +/- 0.7 minutes, respectively. Variations of hepatic arterial anatomy were present in 19 patients (32%) on conventional angiography. In 8 patients (13%), there was discrepancy in the variations of hepatic arterial anatomy between the two techniques: MIP was correct in 7 patients, and VR was correct in 1 patient. The dominant artery supplying segment IV was identified in 51 patients (85%) with MIP and in 39 patients (65%) with VR. There was no significant difference in conspicuity of the hepatic arteries using either the MIP or VR technique. CONCLUSION: In CTA techniques using multidetector-row CT, MIP is superior to VR for the hepatic arterial evaluation of potential LDLT donors in terms of depicting anatomic variations and postprocessing time.     

16层螺旋CT动脉造影对肝癌动脉供血血管显示效果及临床价值

目的:评价16层螺旋CT在肝癌动脉供血血管显示的价值。方法:对65例肝癌患者进行16层螺旋CT增强扫描,将动脉期序列原始扫描数据传至工作站利用容积重建、最大密度投影及多曲面重建法重建腹腔动脉的解剖和走行,观察肝癌病灶动脉供血血管来源情况,其中65例患者行动脉化疗栓塞术前进行了DSA检查,将65例DSA结果与CT血管造影进行对比。结果:65例肝癌患者中,47例肝动脉解剖正常,肝癌病灶动脉血供来源于正常的肝动脉;18例肝动脉解剖变异,肝癌病灶动脉血供来源于变异肝动脉。CTA显示肝动脉血管解剖及变异及肝癌动脉供血来源与DSA完全相同。结论:16层螺旋CT动脉造影对肝动脉血管解剖及变异及肝癌动脉供血血管能较好的显示,对肝癌的外科手术及介入治疗具有重要的指导作用。     

Three-phase CT examination of the pancreatobiliary region using multislice CT with 1-mm collimation

PURPOSE: To evaluate the degree of contrast enhancement and accuracy of imaging of the circulatory phase in the first-pass, second-pass, and third-pass acquisitions in the pancreato-biliary region with 1-mm collimation obtained by multislice computed tomography (CT). MATERIALS AND METHODS: In 53 patients, two sequential acquisitions from the porta hepatis to the pancreas were performed during a single breath-hold, followed by a third-pass acquisition including the liver beginning 15 sec after the second-pass acquisition. Contrast enhancement in each acquisition was measured in the aorta, portal vein and its branches, and pancreas. Four experienced radiologists graded using four-point scoring whether or not each acquisition was appropriate for imaging of the arterial phase, pancreatic phase, and portal venous phase. RESULTS: Aortic enhancement was highest at the beginning of the second-pass acquisition. The portal and splenic veins and pancreas showed maximum enhancement in the second-pass acquisition, while the superior mesenteric vein showed maximum enhancement in the third-pass acquisition. In the visual assessment, significantly higher grades were achieved in the first-pass, second-pass, and third-pass acquisitions with regard to imaging of the arterial phase, pancreatic phase, and portal venous phase, respectively. CONCLUSION: Multislice CT permits the acquisition of three distinct circulatory phases (arterial, pancreatic, and portal venous phases) in the pancreatobiliary region with 1-mm collimation.     

Multidetector CT of the liver and hepatic neoplasms: effect of multiphasic imaging on tumor conspicuity and vascular enhancement

OBJECTIVE: Our aim was to determine which of three contrast-enhanced phases (early arterial, late arterial, or portal venous) was optimal for achieving maximal enhancement of the celiac artery, portal vein, and hepatic parenchyma. We also wanted to learn which phase provided the maximal tumor-to-parenchyma difference when using multidetector CT (MDCT) with fixed timing delays. MATERIALS AND METHODS: Fifty-two patients with suspected or known hepatic tumors underwent multiphasic contrast-enhanced MDCT using double arterial (early and late arterial) and venous phase acquisitions with fixed timing delays. All patients were administered 150 mL of IV contrast material at an injection rate of 4 mL/sec. Images were acquired at 20 sec for the early arterial phase, 35 sec for the late arterial phase, and 60 sec for the portal venous phase. Attenuation measurements of the celiac artery, portal vein, normal hepatic parenchyma, and the hepatic tumor were compared. Three reviewers independently and subjectively rated tumor conspicuity for each of the three phases. Ratings were compared using kappa statistics. RESULTS: Late arterial phase images showed maximal celiac axis attenuation, whereas portal venous phase images revealed the highest portal vein and normal hepatic parenchymal attenuation. Maximal tumor-to-parenchyma differences for hypovascular tumors was superior in the portal venous phase, but we found no significant differences in maximal tumor-to-parenchyma differences for hypervascular tumors among the evaluated phases. On subjective analysis, interobserver agreement was moderate to very good for the three phases. All three reviewers graded both hypovascular and hypervascular tumor conspicuity as superior in either the late arterial phase or the portal venous phase in most patients. In only one patient was the early arterial phase graded as superior to the late arterial and portal venous phases (by two of the three reviewers). CONCLUSION: When MDCT of the liver is performed using fixed timing delays, maximal vascular and hepatic parenchymal enhancement is achieved on either late arterial phase or portal venous phase imaging. In most patients, early arterial phase imaging does not improve tumor conspicuity by either quantitative or subjective analysis.     

Virtual Monoenergetic Spectral Detector CT for Preoperative CT Angiography in Liver Donors

ObjectiveThe purpose of this study was to evaluate the use of virtual monoenergetic images (VMI) in pre-operative CT angiography of potential donors for living donor adult liver transplantation (LDALT), and to determine the optimal energy level to maximize vascular signal-to-noise and contrast-to-noise ratios (SNR and CNR, respectively).Materials and methodsWe retrospectively evaluated 29 CT angiography studies performed preoperatively in potential liver donors on a spectral detector CT scanner. All studies included arterial, early venous, and delayed venous phase imaging. Conventional polyenergetic images were generated for each patient, as well as virtual monoenergetic images in 10 keV increments from 40 –100 keV. Arteries (aorta and celiac, superior mesenteric, common hepatic, right and left hepatic arteries) were assessed on arterial phase images; portal venous system branches (splenic, superior mesenteric, main, right, and left portal veins) on early venous phase images; and hepatic veins on late venous phase images. Vascular attenuation, background parenchymal attenuation, and noise were measured on each set of virtual monoenergetic and conventional images.ResultsBackground hepatic and vascular noise decreased with increasing keV, with the lowest noise at 100 keV. Vascular SNR and CNR increased with decreasing keV and were highest at 40 keV, with statistical significance compared with conventional ( P < 0.05).ConclusionsIn preoperative CT angiography for potential liver donors, the optimal keV for assessing the vasculature to improve SNR and CNR is 40 keV. Use of low keV VMI in LDALT CT protocols may facilitate detection of vascular anatomical variants that can impact surgical planning.