16层螺旋CT全脑动脉成像技术初探

目的评价16层螺旋CT全脑动脉成像的可行性.材料和方法94例均用Toshiba 16层Aquilion螺旋CT扫描机扫描.注射造影剂后于18～19s行动脉期扫描,造影剂总量80～90ml,注射速度3.5ml/s或4ml/s.多种重建方法显示脑动脉.结果94例中,47例(50.0%)达到全脑纯动脉期的显示;27例(28.7%)于扫描起始部未见静脉显影,但于颅中部即可见显影的静脉和回流的静脉窦显示(即半脑动脉期);11例(11.7%)于扫描起始位置即已出现颈内静脉显示;6例(6.4%)虽可见脑动脉显示但密度太淡,难以重建成有效的三维脑动脉影像;3例(3.2%)完全未见血管增强.结论16层螺旋CT扫描可以在部分病例中完成全脑纯动脉期成像,其成功率为50.0%.     

性腺静脉MSCT血管成像及其临床意义

目的：研究女性性腺静脉MSCT血管成像的显示及其解剖变异,探讨性腺静脉与相关临床因素的关系。方法：155例行下腹及盆腔CT增强扫描的连续女性病例,其中25例普通妇科疾病和40例妇科肿瘤作为病例组,30例无下腹及盆腔疾病作为对照组。在性腺静脉最宽处测量管径,计算两组性腺静脉的显示率,比较两组性腺静脉平均管径和显示率。结果：病例组与对照组的性腺静脉显示率皆大于70％,显示率无显著差别。两组性腺静脉平均管径无统计学意义的差别,但年轻病例组（≤30岁）性腺静脉管径较年长病例组（≥60岁）管径显著细小,有统计学意义的差别。结论：多层螺旋CT血管成像能够较好显示GV走行及其解剖变异。性腺静脉的显示率与生育次数有关,随着年龄的增加而升高。动脉期性腺静脉显影与静脉扩张和功能不全有关。性腺静脉血管束征有助于鉴别卵巢与非卵巢起源的女性盆腔肿块。     

左肾静脉及其属支的MSCTA

目的：探讨左肾静脉及其属支的64层MSCTA技术及其影像表现。方法：分析连续100例患者MSCT增强扫描动脉期和静脉期图像上左肾静脉及其各属支的显示情况。MSCT检查采用64层CT机,0.625mm×64i方式采集,0.625mm层厚回顾性重建,标准或软组织算法;对比剂剂量80～90ml,注射流率3～4ml/s,延迟时间动脉期为25～26s、静脉期50～60s。后处理采用三维正交多平面重组（OMPR）、最大密度投影（MIP）和容积再现（VR）三种方法。结果：MSCTA动脉期和静脉期图像上均完整显示左肾静脉主干,静脉期图像上对其3个属支的显示数量（276支）多于动脉期（217支）。VR图像显示这些血管最好。69%的病例为标准的单支左肾静脉和3个属支（肾上腺静脉、生殖腺静脉和腰静脉）,31%的病例有不同程度的变异,部分病例可清楚显示膈静脉（23例）和肾包膜静脉（27例）的汇入。结论：MSCTA静脉期图像结合三维重组技术可以清晰显示左肾静脉及其属支,其中以VR图像最佳;大部分受试者的左肾静脉及属支为标准的单支型,但变异类型较多。     

原发性肝癌经下肢静脉注射造影剂多层螺旋CT增强技术探讨

目的 探讨原发性肝癌经下肢静脉注射造影剂多层螺旋CT(MSCT)增强技术的方法.方法 80例原发性巨块型肝癌按2 ml/kg的剂量注射造影剂行MSCT阈值触发增强扫描.实验组60例分为3个亚组采用3 ml/s、4 ml/s、5 ml/s的注射速率经下肢静脉注射.对照组20例采用3 ml/s的注射速率经上肢静脉注射.分别测量平扫、动脉期、门脉期、平衡期的肝实质、腹腔动脉、肝内肿块的最大增强CT值,统计分析各组间的差异.结果动脉期及门脉期,对照组与实验组5 ml/s组之间的腹腔动脉、肿瘤组织的CT值无统计学差异(P＞0.05),而与实验组3 ml/s、4 ml/s组之间的腹腔动脉、肿瘤组织的CT值有统计学差异(P＜0.05);平衡期,对照组与实验组各组之间的肝实质CT值、以及与实验组4 ml/s、5 ml/s组的腹腔动脉、肿瘤组织的CT值无统计学差异(P＞0.05).结论 在造影剂注射用量相对恒定的条件下,采用MSCT的阈值触发扫描技术,原发性肝癌经下肢静脉5 ml/s的注射速率可以达到经上肢静脉3 ml/s注射速率的增强效果.     

螺旋CT增强扫描显示肝静脉和门静脉及其解剖学形态的临床分析

目的了解2种增强方式的螺旋CT扫描显示肝静脉和门静脉的差异,并熟悉它们在CT图像上的解剖学形态。方法采用3.0 ml/s(行螺旋CT动脉和门脉期双期扫描,简称双期组)和1.5 ml/s(仅行螺旋CT单纯门脉期扫描,简称单期组)2种注射速率的对比剂,分别完成100和50例病人的螺旋CT检查。结果 2组各50例分析结果显示：双期组中有48例在门脉期扫描能够分别清晰显示肝静脉和门静脉1、2、3级分支,而单期组中仅2和4例分别显示肝静脉与门静脉1、2、3级分支。双期组100例分析显示共有10种解剖类型的肝静脉,而门静脉仅见2种类型;15％病人见到1支额外右下肝静脉。结论 3 ml/s速率的螺旋CT门脉期增强扫描能清晰显示肝静脉和门静脉1、2、3级分支;肝静脉解剖变异较门静脉为大。     

多层螺旋CT双通路注射法行肝门静脉系统成像的研究

目的:确定多层螺旋CT肝门静脉系统检查的合理延迟时间及双通路注射对比剂法的可行性。方法:分为2个步骤研究:①随机选择无腹部及心血管疾患的患者53例,以3 ml/s速率注射造影剂20 ml,行同层动态扫描,计算腹主动脉、肝门静脉、下腔静脉、肝实质的对比剂时间密度曲线,及它们的相关性。②47例需门静脉检查的患者,行MDCT肝区移床式、动态扫描,在右肘部静脉及下肢静脉同时注入对比剂,对比剂总量1.5~2 ml/kg。扫描时使用对比剂自动示踪软件,设动脉血管阈值为120 HU启动扫描,动脉期扫描完成后延时20.1±5.54 s行门静脉扫描,分别评价肝门静脉、肝静脉、下腔静脉的显示率及程度。结果:①20 ml对比剂注射同层动态扫描肝门层面腹主动脉达峰时间为18.5±4.81 s,肝门静脉达峰时间是38.61±6.59 s,下腔静脉达峰时间是55.44±12.16 s,肝实质的达峰时间是56±5.7 s。②肝门静脉显示率达100%,肝门静脉主干等显示程度平均评分2.50~2.93;相关小分支静脉显示率为87%~98%,显示平均评分2.25~2.63。结论:MDCT右肘部静脉及下肢静脉同时注入对比剂,在动脉期扫描完成后,延时20.1±5.54 s行肝门静脉检查,肝门静脉系统成像效果良好。     

双排螺旋CT在前胡桃夹综合征诊断中的应用价值

目的:探讨双排螺旋CT在前胡桃夹综合征诊断中的应用价值。方法:回顾性分析6例经临床诊断为前胡桃夹综合征患者的双排螺旋CT影像学资料及临床资料。结果:6例前胡桃夹综合征均显示肠系膜上动脉压迫左肾静脉征象:腹主动脉与肠系膜上动脉之间夹角平均为18°;左肾静脉穿肠系膜上动脉夹角时明显受压,其前后径受压前后之比约4:1;其中2例显示左侧精索静脉扩张,1例显示左侧卵巢静脉扩张。结论:综合应用双排螺旋CT平扫、增强扫描及多种图像后处理技术能够清楚显示腹主动脉和肠系膜上动脉与受压的左肾静脉三者之间的解剖关系,并能发现增强扫描平衡期双肾实质密度差异及精索静脉或卵巢静脉曲张等表现,可作为前胡桃夹综合征确诊的一种重要手段。     

16层螺旋CT肝脏多期扫描的方法与实用价值

目的:探讨16层螺旋CT肝脏多期扫描的方法及应用价值。方法:150例疑有肝脏病变的患者行16层螺旋CT多期扫描。层厚7.5mm,螺距1.375,扫描时间0.8s/r,静脉团注对比剂80～120ml,分别延时23～28s、45～50s58～65s行肝动脉期(动脉早期)、门静脉流注期(动脉晚期)和肝静脉期(实质期)扫描,并对图像作回顾性分析,比较增强前后腹主动脉、门静脉、肝静脉的CT值变化和后处理图像显示肝动脉、门静脉、肝静脉的能力。结果:16层螺旋CT肝脏多期扫描,肝脏血管增强后与增强前的密度差在91.9HU以上,VR、MIP、MPR图像上100%显示肝动脉(150/150),门静脉显示率为96.7%(145/150),肝静脉显示率为95.3%(143/150)。5例门静脉显示不清的病例中,3例为肝癌合并肝门区淋巴结转移,1例肝癌合并门静脉癌栓形成,1例为严重肝硬化合并腹水、脾肿大;7例肝静脉显示不清中有5例与门静脉显示不清的5例为相同病例,其余2例为严重肝硬化合并腹水。结论:16层螺旋CT肝脏多期扫描对评估肝脏病变、肝脏血管的正常、变异以及病变对血管的影响有很大帮助,但是对于严重肝硬化门静脉高压、门静脉狭窄、门静脉血栓(包括癌栓)形成的病例,显示门静脉和肝静脉不理想。     

螺旋CT对活体肝移植的评估意义

目的 探讨多层螺旋CT(MSCT)在活体肝移植供体术前评估中的价值.方法 52名活体亲属供肝者术前均行MSCT扫描,前22名接受平扫及动脉期,门静脉期,肝静脉期3期增强扫描(对比剂注射流率4ml/s,总量100ml,管电压140kV),后30名也接受平扫及动脉期,门静脉期,肝静脉期3期增强扫描,但注射方式改变(第一期对比剂注射流率4ml/s,总量70ml,第二期对比剂注射流率2ml/s,总量30ml,管电压120kV).所有图像最终都经手术术中所见对照,评价MSCT在评估供肝血管,肝实质情况的价值.对2组不同扫描参数的三维(3D)重组图像质量采用Mann-Whitney U 检验,对两组不同扫描参数的总照射剂量采用t检验.结果 CT血管成像对供肝动脉,门静脉,肝静脉,肝脏的容积的显示与术中一致.2组三维(3D)血管重组图像质量评分差别没有统计学意义(Z =-0.062,P=0.951),两组不同扫描参数的总照射剂量差别有统计学意义(f =9.06,P=0.000).结论 MSCT可以直观、准确地评价活体供肝者的血管、体积以及实质病变的情况,在活体供肝术前综合评估中起着重要作用.     

对比剂不同流率对门静脉CT血管成像质量的影响

目的 探讨对比剂不同注射流率对多层螺旋CT肝门静脉成像质量的影响.方法 30例患者随机分为3组,每组10例,年龄与体重无明显差异,行腹部CT增强扫描.按1.5 ml/kg剂量前臂静脉注射浓度为300 mg Ⅰ/ml的非离子型对比剂,注射流率分别为2.0 ml/s、3.0 ml/s和4.0 ml/s.腹主动脉兴趣区智能跟踪技术触发动脉期扫描,动脉期后延迟7 s与20 s行门静脉期扫描.在工作站测量3组CT源图像上门静脉(PV)与肝实质的CT值,并重组PV斜轴位与冠状位最大密度投影(MIP)图像,观察PV显示的分支级别.采用SPSS 11.5软件行统计学分析.结果 2.0 ml/s组、3.0 ml/s组、4.0 ml/s组门静脉CT值分别为(150.80±21.16)HU、(170.90±17.26)HU与(181.90±22.88)HU,2.0 ml/s组与4.0 ml/s组间有明显差别(P=0.017).2.0 ml/s组、3.0 ml/s组、4.0 ml/s组PV与肝实质CT值差别分别是(50.20±17.40)HU、(67.10±23.08)HU与(76.20±22.75)HU,2.0 ml/s组与4.0 ml/s组间有明显差别(P=0.039).2.0 ml/s组、3.0 ml/s组、4.0ml/s组对PV分支显示级别分别为4.20±1.14、4.90±0.99及5.50±0.53,2.0 ml/s组与4.0 ml/s组间有明显差别(P=0.013).结论 注射流率对PV CT血管成像的质量有影响,流率为4.0 ml/s时SCTP质量最佳.     

门静脉癌栓螺旋CT及CT门静脉造影的诊断价值

目的：评价门静脉癌栓螺旋CT及其门静脉血管造影（CTP）的特征及诊断价值。方法：43例门静脉癌栓形成的患者作了螺旋CT平扫和增强扫描，30例进行了多平面重组（MPR）和CTP成像，15例患者治疗的作了CT随访。结果：螺旋CT轴位和MPR图像能清晰显示门静脉癌栓，直接的CT征象为门静脉增粗及充盈缺损23％在动脉期癌栓有不均匀强化；间接征象包括门静脉管壁强化（42％）、侧支循环形成（100％）、门静脉海绵样变（44％）及周围肝脏血流动力学的改变。CTP能直观地评价门静脉的癌栓位置、管径及阻塞程度和侧支循环的情况。CT扫描可很好地显示门静脉癌栓治疗后的变化情况。结论：螺旋CT轴位图像结合MPR和CTP图像，可以便完整的提供门静脉癌栓的全面资料。     

动脉晚期CTA融合图像在肾动静脉系统评估中的价值

目的探讨动脉晚期CTA融合图像在肾动静脉系统评估中的价值。方法26例超声提示肾占位的病人及5例活体供肾者,采用德国Siemens Somatom Sensation 16层螺旋CT机,进行了平扫及动脉早期、动脉晚期及实质期3期增强扫描。数据被传到GE ADW 4.2 Workstation进行3D重建,采用Volume viwer plus voxtool 6.3.19软件包。由2位放射科主任医师对肾动静脉系统显示情况进行评估,意见相左时,通过讨论达成共识。结果动脉晚期CTA融合图像对副肾动脉和肾动脉提前分支的显示率与动脉早期相同。左右肾副肾动脉的CTA显示率分别为32.3%和6.5%。左右肾动脉提前分支的显示率分别为12.9%和9.7%。对环主动脉左肾静脉、腹主动脉后左肾静脉及多条右肾静脉,动脉晚期CTA融合图像与实质期的显示率之间亦无差异,分别为16.1%、3.2%及32.3%。动脉晚期CTA融合图像对左肾上腺静脉、左性腺静脉及左腰静脉的显示率为83.9%、87.1%、61.3%,和实质期相比(分别为87.1%、93.5%、64.5%),2组之间无统计学差异(P>0.05)。动脉晚期CTA融合图像质量优于实质期。结论动脉晚期CTA融合图像能够同时且清楚地显示肾动静脉系统,减少了受检者的放射线剂量、节约了检查时间。     

Multi-detector row helical CT angiography of hepatic vessels: depiction with dual-arterial phase acquisition during single breath hold

PURPOSE: To determine by using multi-detector row computed tomography (CT), in a triphasic hepatic dynamic study, which included single breath-hold dual-arterial phase acquisition, the accuracy and frequency of visualization of the small hepatic arterial and portal venous anatomy with angiographic correlation. MATERIALS AND METHODS: In 62 patients, pre- and postcontrast triphasic helical CT were performed by using a multi-detector row CT scanner, with 2.5-mm detector row collimation, at a pitch of 6. The first and second arterial phases were performed during a single breath hold. One reader, blinded to the results of the angiography, reviewed the first arterial phase images on a cine display to assess hepatic arterial anatomy. Visualization of the portal vein and its branches was assessed by using second arterial and portal venous phase images. RESULTS: Major arterial trunks (celiac, hepatic, superior mesenteric, and left gastric) were depicted in all cases. Visualization of small arteries was as follows: right and left hepatic, 62 (100%) of 62; middle hepatic, 52 (87%) of 60; cystic, 47 (90%) of 52; right gastric, 50 (89%) of 56; and right and left inferior phrenic, 57 (92%) and 55 (89%) of 62, respectively. Subsegmental or more peripheral branches of the portal vein were depicted in 83% of cases during the second arterial phase and in 96% during the portal phase. There was no difference in degree of visualization in these two phases. CONCLUSION: Multi-detector row CT angiography was able to depict the hepatic vascular anatomy.     

Dual-phase 3D CT angiography during a single breath-hold using 16-MDCT: assessment of vascular anatomy before laparoscopic gastrectomy

OBJECTIVE: In this study, we evaluated the efficacy of dual-phase 3D CT angiography (CTA) during a single breath-hold using 16-MDCT in the assessment of vascular anatomy before laparoscopic gastrectomy. MATERIALS AND METHODS: The study involved 20 consecutive patients (10 men, 10 women; mean age, 59 years) scheduled for laparoscopic gastrectomy for the treatment of early gastric cancer. A dual-phase contrast-enhanced CT scan using 16-MDCT was obtained before laparoscopic gastrectomy. After rapid infusion of a nonionic contrast agent, arterial and venous phase scans were obtained serially with an interval of 15 sec during a single breath-hold of 31 sec. Three-dimensional CTA images in the arterial phase (3D CT arteriography) and venous phase (3D CT venography) were individually reconstructed using the volume-rendering technique, and then the images were fused together. We evaluated the detectability of the celiac trunk, left gastric artery (LGA), right gastric artery (RGA), left gastric coronary vein (LCV), Henle's gastrocolic trunk, right gastroepiploic vein (RGEV), and accessory right colic vein on 3D CTA to compare with surgical findings. RESULTS: In all 20 patients, 3D CT arteriography and venography clearly showed the celiac trunk, LGA, RGA, Henle's gastrocolic trunk, RGEV, and accessory right colic vein, which were correctly identified during surgery. The branching pattern of the celiac trunk was classified as Michels type I in 19 patients and Michels type II in one patient. Imaging showed the RGA originating from the proper hepatic artery (PHA) in nine patients; from the gastroduodenal artery (GDA) in seven patients; and from the left hepatic artery (LHA) in four patients. In 12 patients, the LCV joined the portal vein (PV) and in eight, the splenic vein (SV). In all patients, the accessory right colic vein joined the RGEV, and Henle's gastrocolic trunk proximal to the joining point flowed to the superior mesenteric vein (SMV). In all 20 patients, the fused image simultaneously showed arteries and veins around the stomach, with no mismatch between the arterial and venous phase images. In 10 patients, the LCV joined the PV after running along the dorsal side of the PHA, common hepatic artery (CHA), or splenic artery (SA). In eight patients, the LCV joined the SV after running along the ventral side of the PHA, CHA, or SA. In two patients, the LCV joined the PV after running along the ventral side of the CHA, which correlated with the surgical findings. Both the sensitivity and positive predictive values of 3D CTA revealed 100% correct identification of the celiac trunk, LGA, RGA, LCV, Henle's gastrocolic trunk, RGEV, and accessory right colic vein. CONCLUSION: Dual-phase 3D CTA using 16-MDCT clearly revealed individual arteries and veins around the stomach before laparoscopic gastrectomy. The fused image of 3D CT arteriography and venography during a single breath-hold enabled the simultaneous assessment of arteries and veins before laparoscopic gastrectomy.     

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.     

Spiral CT findings in a case of pulmonary sequestration

Pulmonary sequestration has always been diagnosed by direct demonstration of the vessels tributary to the lesion, usually by angiography. Conventional CT can identify the arterial supply in only two thirds of cases. We report a case of pulmonary sequestration diagnosed using Spiral CT, based on the demonstration of both arterial supply and venous drainage. The capabilities of Spiral CT to detect subtle vessel abnormalities and to yield reliable multiplanar imaging enabled us to show the whole course of both the artery and the vein tributary to the lesion. Axial images were the most useful ones to diagnose pulmonary sequestration; 2D and 3D reconstructions were useful for a detailed and immediate spatial depiction of the parenchymal abnormality and of its vascular pedicle.     

Evaluation of the renal venous system on late arterial and venous phase images with MDCT angiography in potential living laparoscopic renal donors

OBJECTIVE: The objective of our study was to assess whether both renal arteries and renal veins can be evaluated using single-phase MDCT data sets alone to eliminate the need for both arterial and venous phase data sets. MATERIALS AND METHODS: One hundred consecutive potential living renal donors who underwent 4-MDCT were evaluated. CT was performed with 120 mL of IV contrast material at an injection rate of 3 mL/sec. Both late arterial and venous phase acquisitions were obtained at 25 and 55 sec from the start of IV contrast injection, respectively. The number of the right and left renal veins and its anatomic variations were assessed by two reviewers. Late arterial phase images were evaluated initially, and then venous phase images were analyzed to assess opacification of the renal vein and to see whether venous phase data sets changed or added information about the venous anatomy as seen on late arterial phase images. RESULTS: The retroaortic left renal vein was found in two subjects, and the circumaortic left renal vein was detected in three subjects. The renal veins were adequately opacified on late arterial phase images in all subjects. There were six subjects who had a normal left renal vein with a small posterior branch coursing posterior to the aorta and draining into the inferior vena cava, which were difficult to differentiate from the lumbar vein or ascending lumbar vein; in three of these six subjects, the small posterior branch was opacified only on venous phase images. CONCLUSION: Late arterial phase images obtained at 25 sec after the start of contrast injection can reveal the renal vein anatomy except for a small posterior branch of the left renal vein difficult to differentiate from the lumbar or ascending lumbar vein, as seen in three subjects. The data suggest that venous phase imaging is not necessary for the evaluation of renal vein anatomy.     

Preoperative assessment of vascular anatomy around the stomach by 3D imaging using MDCT before laparoscopy-assisted gastrectomy

OBJECTIVE: Our aim was to evaluate the efficacy of 3D imaging using MDCT in the preoperative assessment of the vascular anatomy around the stomach before laparoscopy-assisted gastrectomy. SUBJECTS AND METHODS. Thirty-six consecutive patients scheduled for laparoscopy-assisted distal gastrectomy were evaluated on MDCT. CT was performed at the arterial phase after a bolus IV injection of contrast material. Three-dimensional CT angiography (3D CTA) of the arterial and venous systems was reconstructed separately using a volume-rendering algorithm, and the images were fused. Three-dimensional CTA for the left gastric, right gastric, and replaced left hepatic arteries and the left gastric coronary vein was evaluated prospectively by three reviewers, and then a surgical correlation was made. RESULTS: In all 36 cases, the left gastric artery was correctly identified on 3D CTA. In 35 of 36 cases, the right gastric artery was correctly identified, whereas in one case, the right gastric artery could not be visualized on 3D CTA because of its small size. In 35 of 36 cases (i.e., one case with agenesis of the left gastric coronary vein was excluded), the left gastric coronary vein was correctly identified. In six cases, the replaced left hepatic artery was correctly identified on 3D CTA. All 36 cases underwent successful laparoscopy-assisted distal gastrectomy on the basis of the 3D CTA. Both the sensitivity and positive predictive values of 3D CTA revealed 100% correct determination of the left gastric artery, replaced left hepatic artery, and left gastric coronary vein. The sensitivity and positive predictive values for the right gastric artery were 97% and 100%, respectively. CONCLUSION: Three-dimensional CTA using MDCT clearly revealed individual vascular anatomies around the stomach and could play an important role in safely facilitating the laparoscopy-assisted gastrectomy procedure.     

The cisterna chyli: enhancement on delayed phase MR images after intravenous administration of gadolinium chelate

PURPOSE: To retrospectively evaluate cisterna chyli (CC) enhancement on magnetic resonance (MR) images obtained after intravenous administration of a gadolinium-based contrast agent. MATERIALS AND METHODS: This retrospective HIPAA-compliant study of 1.5-T MR imaging findings was institutional review board approved; informed patient consent was waived. All MR examinations involved the acquisition of heavily T2-weighted single-shot fast spin-echo (SSFSE) images and three-dimensional (3D) gradient-echo images obtained before and during the arterial, venous, and 3-5-minute delayed phases after intravenous bolus injection of gadopentetate dimeglumine. Included were the data of 59 patients (37 men, 22 women; mean age, 59 years) who had a CC 4 mm or greater in transverse diameter, which was identified as a tubular structure with fluid signal intensity (SI) on SSFSE images. The SI of the CC relative to the spinal canal (SC) was noted and was measured on 3D gradient-echo images obtained during all phases. The Student t test was performed for statistical evaluations. RESULTS: Mean CC-SC SI ratios on nonenhanced, arterial phase, venous phase, and delayed phase images were 0.92, 0.98, 0.99, and 2.13, respectively. The CC had low SI on all 3D gradient-echo images obtained during the nonenhanced, arterial, and venous phases and high SI, similar to the azygos vein SI, on all delayed phase images. The CC-SC SI ratio during the delayed phase was significantly higher than that during the other phases (P<.001). CONCLUSION: The CC has minimal or no enhancement on arterial phase and venous phase images but intense enhancement--similar to the enhancement of veins--on delayed phase images. Comparison of delayed phase images with SSFSE and venous phase images may help to distinguish the CC seen on delayed phase images from lymph nodes, the azygos vein, or esophageal varices.     

HDCT能谱技术提高肝脏门静脉血管成像质量的可行性研究

目的探讨能谱技术在提高CT门静脉成像质量方面的价值。资料与方法 21例可疑肝脏病变的患者,采用能谱扫描模式行动脉期、门静脉期扫描后,运用能谱分析软件获得最佳对比信噪比单能图像和70 keV单能图像。测量传统(混合能量,QC)图像和70 keV单能图像、最佳对比信噪比单能图像中门静脉的信号噪声比(SNR)和对比噪声比(CNR),并对三组图像行容积再现(VR)、最大密度投影法(MIP)重组,采用双盲法对重组质量进行评估。对三组图像的数据行单因素方差分析。结果混合能量图像、70 keV单能图像、最佳CNR的单能图像同层对比,发现最佳CNR的单能图像的SNR、CNR大于混合能量图像和70 keV单能图像,差异有显著统计学意义(P<0.01)。最佳CNR的单能图像的VR、MIP重组图像对门静脉分支的显示级别优于混合能量图像和70 keV单能图像,差异有显著统计学意义(P<0.01)。结论最佳CNR的单能图像可以提高CT门静脉成像(CTPV)门静脉分支的显示级别和图像质量。