多层螺旋CT胰腺检查:多期增强扫描的最佳延迟时间研究

目的 确定合理的多层螺旋CT(MSCT)胰腺检查多期增强扫描延迟时间。方法 随机选择61例无胰腺疾病患者，分为2个步骤研究：(1)21例行胰腺同层动态增强扫描，对比剂总量为120ml，注射流率为5ml／s，分别测定胰周主动脉、胰周门静脉、胰腺实质及肝脏实质在增强后不同时间点的CT值，确立最佳的多期(动脉期、胰腺期及肝脏期)增强扫描延迟时间。(2)40例行MSCT胰腺移床式、多期动态增强扫描，对比剂总量和注射流率同上，分别评价动脉期与胰腺期胰周血管的显示率及显示程度。结果 (1)同层动态扫描结果提示，胰周主动脉强化到达峰值平均时间为30s(延迟时间20s时胰周主动脉CT值已达200HU左右)，胰腺实质强化到达峰值平均时间为40s，胰周门静脉强化到达峰值平均时间为45s，肝脏实质强化到达峰值平均时间为60s(60-80s，基本处于一平台期)；(2)胰周大动脉于动脉期显示率为lOO%，显示程度平均评分为2．93～2．95，胰周其他主要动脉期显示率为78％～98％，显示程度平均评分为0．85～2．63；胰周大静脉于胰腺期显示率为100％，显示程度平均评分为2．80～2、88，胰周其他主要静脉胰腺期显示率为90％～100％，显示程度平均评分为1．08～1．90。结论 MSCT行胰腺检查，须进行三期增强扫描，推荐延迟时间分别为：动脉期为20s、胰腺期为45s、肝脏期为80s。     

多层螺旋CT胰腺检查:不同注射条件下时间窗的选择

目的探讨多层螺旋CT胰腺三期增强扫描,不同注射条件下时间窗的选择。资料与方法40例无胰腺疾病患者,随机分为A、B两组各20例,A组注射条件为:对比剂总量为120ml,注射流率为5ml/s;B组注射条件为:对比剂总量为90ml,注射流率为3ml/s。行胰腺同层动态增强扫描,于不同时间点,分别测定胰腺、肝脏实质及胰周主动脉、门静脉的CT值,最后分别绘制时间密度曲线。结果两组胰周主动脉强化到达峰值的平均时间分别为(33.2±3.8)s(A组)及(40.1±3.8)s(B组),而20s(A组)及25s(B组)时胰周动脉CT值多可达200HU;胰腺实质强化到达峰值的平均时间分别为(42.7±3.3)s(A组)及(46.8±4.5)s(B组);胰周门静脉强化到达峰值的平均时间分别为(47.5±4.8)s(A组)及(53.3±4.8)s(B组);肝脏实质强化到达峰值的平均时间分别为(59.2±4.7)s(A组)及(64.2±4.5)s(B组)。结论在不同的注射条件下,多层螺旋CT胰腺检查三期增强扫描的时间窗的设定并不相同。笔者推荐,对比剂总量为120ml,注射流率为5ml/s时,动脉期延迟时间为20s,胰腺期延迟时间为45s,肝脏期延迟时间为65s;对比剂总量为90ml,注射流率为3ml/s时,动脉期延迟时间为25s,胰腺期延迟时间为50s,肝脏期延迟时间为65s。     

螺旋CT双期扫描技术及其在胰腺癌诊断中的价值

目的：探讨螺旋CT双期扫描技术及其对胰腺癌的诊断价值。方法：正常人60例及胰腺癌44例分两组行螺旋CT双期扫描：A组40例,分动脉期和门动脉期（注射对比剂后20s和60s）扫描;B组64例,分胰腺期和肝脏期（注射对比剂后35s和70s)扫描。分别测定各期胰腺、病灶及胰周大血管的CT值,计算胰腺期及肝脏期胰周小静脉的显示率,并行统计学处理,对扫描时相的比较采用方差分析及q检验处理,对胰周小静脉的显示率采用x^2检验分析。结果：正常组,胰腺在胰腺期的增强值高于其他3期（F＝13．45,P＜0．0001）胰周大血管在胰腺期显示良好。胰周小静脉的显示率,胰腺期优于肝脏期（x^2=4．44,12．38,4．81,P＜0．05）;异常组,胰腺与病灶的增强差值,胰腺期明显大于其他3期（F＝14．90,P＜0．0001）,发现小胰腺癌4例。胰周大血管受侵者占不可切除性肿瘤的54％（19／35）,胰周小静脉迂曲扩张者占42％（10／42）。肝转移灶占37％（13／35）。结论：胰腺螺旋CT双期扫描宜分为胰腺期和肝脏期,该技术在胰腺癌的诊断中具有非常重要的临床价值。     

多层螺旋CT胰腺三期增强扫描的临床价值

目的　探讨多层螺旋CT(MSCT)胰腺三期增强扫描的临床价值。资料与方法　随机选择 4 0例无胰腺疾病患者 ,进行平扫及三期 (动脉期、胰腺期及肝脏期 )增强扫描。分别测量平扫及三期增强扫描时胰腺实质密度 ,根据三期增强扫描胰腺实质密度较增强前提高程度 ,比较三期增强扫描胰腺实质强化的情况 ;同时分别评价动脉期与胰腺期胰周血管的显示率及显示程度 ,并行统计学分析。结果　三期增强扫描中 ,胰腺期胰腺实质密度较平扫提高程度最为明显 ,胰腺期与动脉期及胰腺期与肝脏期 ,差异均非常显著 (P <0 .0 0 1)。对于胰周大动脉显示率 ,动脉期与胰腺期无统计学差异 (P >0 .0 5 ) ,而对其显示程度 ,则差异非常显著 ,动脉期明显优于胰腺期 (P <0 .0 0 1) ;对于胰周大静脉、胰周主要动、静脉的显示率及显示程度 ,动脉期与胰腺期则均有显著性差异 (P <0 .0 1)。结论　MSCT胰腺检查 ,一般宜行三期增强扫描 :动脉期、胰腺期及肝脏期 ;若已于MSCT检查前明确为不可切除性胰腺癌 ,亦可行双期增强扫描 :胰腺期及肝脏期。     

多层螺旋CT三期扫描对正常胰腺和胰周血管增强特性的研究

目的　探讨多层螺旋CT多期增强扫描胰腺实质和胰周血管的强化特点。方法　对 60例正常人群行螺旋CT三期扫描 ,即动脉期 (2 0s)、胰腺期 (3 5～ 42s)、肝脏期 (75～ 80s) ,分别测量各期胰腺及胰周血管的CT值 ,并行统计学分析。结果　胰腺在胰腺期增强峰值高于其它两期 (Ρ <0 .0 1) ,对胰周动脉的增强值胰腺期与动脉期无明显差异 (Ρ >0 .0 5 ) ,但明显高于肝脏期 (Ρ <0 .0 1) ,对胰周静脉的增强值胰腺期与肝脏期无明显差异 (Ρ >0 .0 5 ) ,却明显高于动脉期 (Ρ <0 .0 1)。结论　多层螺旋CT三期扫描尤其胰腺期明显增强胰腺和胰周血管 ,对胰腺疾病的诊断和分期有重要价值。     

胰腺MRI:动态增强扫描最佳延迟时间窗的研究

目的构筑正常胰腺时间-增强指数曲线,确定胰腺动态增强MRI最佳延迟扫描时间窗。方法60例非胰腺疾病患者,随机分为A、B、C3组各20例,用小剂量团注法测对比剂达腹主动脉峰值时间,按公式Delay=TV-A-1/4TA t,使3组分别于t为0s、5s、10s行多时相动态增强MRI扫描。测量胰腺、肝脏及胰周血管的信号强度,计算增强指数,并对图像质量进行评分。结果B组在对比剂达腹主动脉后延迟5s扫描,胰腺实质增强指数为18.6,明显高于A组10.4和C组15.0(P<0.05),同时胰周动脉强化程度良好;延迟33s扫描,肝脏及胰周静脉增强指数分别为14.3和21.0,高于A组的10.7和15.8(P<0.05),而与C组的肝实质13.1无统计学差异(P>0.05)。结论在对比剂到达腹主动脉后延迟5s和33s左右行屏气扫描,是获得高质量胰腺MRI双期动态增强扫描的实用技术。     

使用MSCT灌注法研究受体肝多期扫描的最佳延迟时间

目的：探讨64层螺旋CT灌注方法在确定肝移植受体肝脏多期增强扫描最佳延迟时间中的应用价值。方法：选取拟接受肝移植术患者25例（男17例、女8例）,采用5ml／s的注射流率经外周静脉注入对比剂50m,行肝门层面同层动态扫描。运用CT灌注的后处理方式绘制腹主动脉、门静脉强化的时间-密度曲线,获得肝动脉、门静脉的强化峰值及其达峰时间并行统计学分析。结果：腹主动脉平均最大强化值（288±20．14）HU、平均达峰时间（18．48±1．046）s,门脉主干平均最大强化值（135．12±24．91）HU、平均达峰时间（35．36±2．139）s,门脉达峰后平台期持续时间19．5s。结论：64层螺旋CT灌注方法可以用于确定肝移植受体肝脏多期增强扫描的最佳延迟时间。分别为动脉早期18s,动脉晚期35s,门脉期50s,延迟期85s。其中动脉晚期结合肝脏延迟期扫描有利于肝内富血供病灶的检出和定性诊断。     

螺旋CT动态扫描胰腺实质强化时相优化的探讨

目的　利用螺旋CT动态增强扫描探讨胰腺实质最佳强化时相。材料与方法　随机选取临床及影像学检查排除胰腺病变而行上腹部CT检查者 40例。选择胰腺实质显示最完整一层作动态增强扫描 ,扫描周期为 4s(其中扫描时间 1s ,间隔 3s) ,团注对比剂后 ,延迟时间 15s ,持续扫描至 71s ,共作 15层动态扫描。结果　 40例正常胰腺实质高峰时相的分布为 :36例 ( 90 % )在 39～ 5 1s之间 ,1例 ( 2 .5 % )小于 39s ,3例 ( 7.5 % )大于 5 1s。腹主动脉 38例 ( 95 % )在 33～ 47s之间达到高峰 ,2例 ( 5 % )小于 33s。结论　经螺旋CT同层动态增强扫描 ,当采用 2ml/kg体重对比剂剂量 ,注射速度为 3ml/s时 ,正常胰腺实质最佳强化时相为 39～ 5 1s ,即胰腺实质期。腹主动脉及其主要分支最佳强化时相为 33～ 47s     

用峰值跟踪法行颅脑动脉期CT增强扫描

目的:对进行颅脑部动脉期CT增强扫描时,排除各种影响因素对扫描延迟时间的影响。方法:在平扫图像中的胸主动脉进行标记;在注射对比剂10~15s后,每1s、2s或3s各进行扫描一次;当胸主动脉CT值超过100HU时,立即按下扫描按键,3s后CT机进行扫描。结果:38例进行颅脑部动脉期CT值峰值跟踪扫描的患者,动脉期颅脑部显示满意度达到100%,对扫描出的图像进行胸主动脉CT值测量,其值平均为269HU。结论:用峰值跟踪的方法进行颅脑部动脉期CT增强扫描比人为估计延迟时间的方法精确,扫描效果好。     

猪正常胰腺的CT、MRI表现及多期增强扫描方案的研究

目的：探讨大动物猪正常胰腺的CT、MRI表现及多期增强扫描的最佳方案,为猪作为胰腺病模型动物提供参考资料。方法：健康幼猪10只,行CT平扫及薄层动态增强扫描,其中6只同时行MRI扫描,序列包括T1WI、T2WI、DWI、MRCP。扫描结束后10只猪均剖腹及离体观察胰腺的形态及位置,并与影像学表现对照。结果：①猪胰腺分为胰头及左、右两叶,呈“三叶草”形。其中左叶为胰腺的主体部分,其解剖位置、大体形态、胰周血管、胰实质密度、MRI T1加权像、T2加权像信号、弥散加权成像（DWI）信号及ADC值等均与人类胰腺十分相近;②MRCP显示猪的胰胆管系统与人不同,分别开口于十二指肠,相距约5—9cm;胆管较粗,直径约5～6mm,易显示;而胰管纤细,值径约1～1．5mm,生理状态下MRI对其显示欠佳;③螺旋CT多期增强扫描时间密度曲线与人类相似,但胰腺三期增强扫描即动脉期、胰实质期、门脉期最佳延迟时间较人早,分别为15s、35s、45s。结论：大动物猪胰腺的CT、MRI表现及多期增强扫描方案与人类有许多相似之处,可作为胰腺疾病影像学研究的理想平台。     

不同扫描方案的多层螺旋CT检查在胰腺癌术前评估中的价值

目的:通过对3组病例行不同扫描时相的多层螺旋CT检查,分析不同扫描方案的胰腺多期增强扫描在胰腺癌术前评估中的价值。方法:将临床因怀疑胰腺癌而申请MDCT检查的病例随机分为3组,行不同扫描时相的MDCT增强扫描。三组病例的扫描时相分别为:第1组(动脉期和门脉期),第2组(胰腺实质期和门脉期),第3组(动脉期、胰腺实质期和门脉期)。图像分析内容包括肿瘤位置、有无周围器官及主要血管的侵犯、有无器官转移、腹膜或腹腔转移等,最后评估肿瘤是否可以手术切除,并与手术结果对照。计算每组病例的阳性预测值、阴性预测值、敏感性、特异性及准确率,并将诊断结果进行统计检验。结果:三组病例对于胰腺癌术前可切除性评价的阳性预测值、阴性预测值、敏感度、特异度及准确率分别为第1组:93.5%、66.7%、87.9%、80%及86%;第2组:100%、80%、93.8%、100%及95.0%;第3组:100%、87.5%、97.1%、100%及97.6%。第1组诊断结果与第3组间差异有显著性意义。结论:胰腺实质期与门脉期应作为胰腺癌术前MDCT增强的最基本扫描时相,如果需要进一步观察胰周动脉走行及肿瘤的供血情况,可以加做动脉期扫描。以原始横断面图像为基础,结合MPR、MIP、VR、CPR等重建技术,MDCT对于胰腺癌的术前可切除性评价多能做出正确诊断。     

High-concentration contrast media in multiphasic abdominal multidetector-row computed tomography: effect of increased iodine flow rate on parenchymal and vascular enhancement

OBJECTIVE: The purpose of this study was to assess the influence of the iodine flow rate on parenchymal and vascular enhancement during multiphasic abdominal multidetector-row computed tomography (MDCT). METHODS: Fifteen patients underwent MDCT at an iodine flow rate of 1.2 g/s as well as 1.6 g/s (group A, protocols 1 and 2), and 90 patients underwent MDCT at an iodine flow rate of 1.2 g/s (group B) or 1.6 g/s (group C). Measurements were performed for all groups in the liver, spleen, pancreas, portal vein, inferior vena cava, and abdominal aorta. RESULTS: Aortal and pancreatic enhancement during the arterial phase was significantly higher with the higher iodine flow rate. The mean difference in aortal enhancement was 60 Hounsfield units (HU) between protocols 1 and 2 of group A, and the mean difference was 70 HU between groups B and C. The mean difference in pancreatic enhancement was 10 HU between protocols 1 and 2 of group A and 17 HU between groups B and C. During the portal and hepatic venous phases, no significant difference in enhancement was observed. CONCLUSION: A high iodine flow rate in multiphasic abdominal MDCT improves enhancement of the aorta and the pancreas during the arterial phase but does not influence later phases.     

螺旋CT表面覆盖法成像对胰腺癌诊断价值的探讨

目的评价螺旋ＣＴ表面覆盖法（ＳＳＤ）在胰腺癌诊断中的价值。材料与方法对２０例经病理及临床证实的 胰腺癌患者进行螺旋ＣＴ薄层增强扫描,并对原始图像行ＳＳＤ法三维重建。结果２０例胰周血管ＳＳＤ成像良好,下腔静脉、门静脉及其１级属支、腹主动脉及其２级分支的显示率为６５％～１００％;ＳＳＤ像均能显示胰腺肿瘤与邻近结构的三维解剖关系,包括周围血管、胆胰管等,表明上述结构的受侵、受压及其并发症。结论ＳＳＤ图像可以明确地显示病灶及胰周结构的空间关系,弥补轴位图像的不足,更有助于诊断和指导手术。     

Sixty-four MDCT achieves higher contrast in pancreas with optimization of scan time delay

AIM: To compare different multidetector computed tomography (MDCT) protocols to optimize pancreatic contrast enhancement. METHODS: Forty consecutive patients underwent contrast-enhanced biphasic MDCT (arterial and portalvenous phase) using a 64-slice MDCT. In 20 patients, the scan protocol was adapted from a previously used 40-channel MDCT scanner with arterial phase scanning initiated 11.1 s after a threshold of 150 HU was reached in the descending aorta, using automatic bolus tracking (Protocol 1). The 11.1-s delay was changed to 15 s in the other 20 patients to reflect the shorter scanning times on the 64-channel MDCT compared to the previous 40-channel system (Protocol 2). HU values were measured in the head and tail of the pancreas in the arterial and portal-venous phase. RESULTS: Using an 11.1-s delay, 74.2 HU (head) were measured on average in the arterial phase and 111.2 HU (head) were measured using a 15-s delay (P <0.0001). For the pancreatic tail, the average attenuation level was 76.73 HU (11.1 s) and 99.89 HU (15 s) respectively (P = 0.0002). HU values were also significantly higher in the portal-venous phase [pancreatic head: 70.5 HU (11.1 s) vs 84.0 HU (15 s) (P = 0.0014); pancreatic tail: 67.45 HU (11.1 s) and 77.18 HU (15 s) using Protocol 2 (P = 0.0071)]. CONCLUSION: Sixty-four MDCT may yield a higher contrast in pancreatic study with (appropriate) optimization of scan delay time.     

Optimized scan delay for late hepatic arterial or pancreatic parenchymal phase in dynamic contrast-enhanced computed tomography with bolus-tracking method

Objectives:To determine the optimal scan delay corresponding to individual hemodynamic status for pancreatic parenchymal phase in dynamic contrast-enhanced CT of the abdomen.Methods:One hundred and fourteen patients were included in this retrospective study (69 males and 45 females; mean age, 67.9 ± 12.1 years; range, 39–87 years). These patients underwent abdominal dynamic contrast-enhanced CT between November 2019 and May 2020. We calculated and recorded the time from contrast material injection to the bolus-tracking trigger of 100 Hounsfield unit (HU) at the abdominal aorta (s) (Time_TRIG) and scan delay from the bolus-tracking trigger to the initiation of pancreatic parenchymal phase scanning (s) (Time_SD). The scan delay ratio (SDR) was defined by dividing the Time_SD by Time_TRIG. Non-linear regression analysis was conducted to assess the association between CT number of the pancreas and SDR and to reveal the optimal SDR, which was ≥120 HU in pancreatic parenchyma.Results:The non-linear regression analysis showed a significant association between CT number of the pancreas and the SDR (p < 0.001). The mean Time_TRIG and Time_SD were 16.1 s and 16.8 s, respectively. The SDR to peak enhancement of the pancreas (123.5 HU) was 1.00. An SDR between 0.89 and 1.18 shows an appropriate enhancement of the pancreas (≥120 HU).Conclusion:The CT number of the pancreas peaked at an SDR of 1.00, which means Time_SD should be approximately the same as Time_TRIG to obtain appropriate pancreatic parenchymal phase images in dynamic contrast-enhanced CT with bolus-tracking method.Advances in knowledge:The hemodynamic state is different in each patient; therefore, scan delay from the bolus-tracking trigger should also vary based on the time from contrast material injection to the bolus-tracking trigger. This is necessary to obtain appropriate late hepatic arterial or pancreatic parenchymal phase images in dynamic contrast-enhanced CT of the abdomen.     

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。     

Improvement of parenchymal and vascular enhancement using saline flush and power injection for multiple-detector-row abdominal CT

The aim of this study was to determine if a saline solution flush following low dose contrast material bolus improves parenchymal and vascular enhancement during abdominal multiple detector-row computed tomography (MDCT). Forty-one patients (24 men and 17 women; mean age 49 years, age range 27–86 years) underwent abdominal MDCT (collimation 4×5 mm, 15-mm table increment, reconstruction interval 5 mm, gantry rotation period 0.8 s) with a single- as well as with a double syringe power injector. Indication for examination were benign and malignant tumors and inflammatory diseases. Patients received 100 ml nonionic contrast material (300 mgI/ml) alone or pushed with 20 ml saline solution. Mean enhancement values for both protocols were measured in the liver, the spleen, the pancreas, the renal cortex, the portal vein, the inferior vena cava and the abdominal aorta. Double syringe power-injector protocol led to significantly higher parenchymal and vascular enhancement than single syringe power-injector protocol (p<0.05). The improvement in mean enhancement of the liver was 9±9 HU, of the spleen 8±10 HU, of the pancreas 7±9 HU, and of the renal cortex 8±20 HU. The improvement in mean enhancement of the portal vein was 10±17 HU of the inferior vena cava 8±13 HU and of the abdominal aorta 10±17 HU. The use of a double syringe power injector with saline flush following contrast material bolus significantly improves parenchymal and vascular enhancement during contrast-enhanced abdominal MDCT with low iodine doses.     

Pancreatic malignancy: value of arterial, pancreatic, and hepatic phase imaging with multi-detector row CT

PURPOSE: To assess the value of arterial, pancreatic, and hepatic phase imaging at multi-detector row computed tomography (CT) of the pancreas for pancreatic malignancy. MATERIALS AND METHODS: Thirty-nine patients suspected of having resectable pancreatic adenocarcinoma underwent triple-phase multi-detector row CT. Images obtained during each phase were interpreted by one radiologist who evaluated presence of tumor, vascular invasion, and flow artifacts in the superior mesenteric vein and measured attenuation of tumor, normal pancreas, aorta, and superior mesenteric vein. Results were compared with histologic, follow-up, and correlative imaging findings. RESULTS: Mean tumor-to-gland attenuation difference was greatest on images obtained in the pancreatic phase (42 HU) versus that on those obtained in the hepatic phase (35 HU) and in the arterial phase (25 HU). For tumor detection, sensitivity of the images obtained in pancreatic (0.97 [29 of 30]) and hepatic (0.93 [28 of 30]) phases was superior to that of those obtained in arterial phase (0.63 [19 of 30]) (P < or =.008). For vascular invasion detection, sensitivity of images obtained in the hepatic phase (0.83) was better than that of those obtained in the pancreatic (0.58) and arterial (0.25) phases. Images obtained in the pancreatic phase demonstrated more flow artifacts and decreased attenuation in the superior mesenteric vein, compared with the artifacts revealed on images obtained in the hepatic phase. CONCLUSION: Routine acquisition of images in the arterial phase is unnecessary for detection of pancreatic adenocarcinoma. Images of the pancreas obtained in the hepatic phase with multi-detector row CT most accurately display vascular invasion.     

Pancreatic adenocarcinoma: analysis of the effect of various concentrations of contrast material

PURPOSE: The aim of this study was to compare the efficacy of two contrast materials with moderate and high iodine concentrations for the depiction of pancreatic adenocarcinoma. MATERIALS AND METHODS: A series of 107 patients with histologically proven pancreatic adenocarcinoma underwent helical computed tomography. A fixed dose of 100 ml of iopamidol 300 (mg I/ml) was administered to 50 patients (group A) and iopamidol 370 (mg I/ml) to 57 patients (group B) at the same injection rate (3 ml/s). Unenhanced helical scans and contrast-enhanced scans for three phases (30, 70, and 300 s after starting the infusion of contrast material) were obtained. We evaluated enhancement of the aorta, portal vein, hepatic parenchyma, pancreatic parenchyma, and pancreatic adenocarcinoma during each phase. RESULTS: During all phases, both aortic and pancreatic enhancement were significantly greater in group B than in group A (P<0.01). Enhancement of the portal vein and hepatic parenchyma was significantly greater at 70 and 300 s in group B than in group A (both P<0.01). Tumor-to-pancreas contrast was significantly greater in group B than in group A at both 30 s (P<0.01) and 70 s (P<0.05). CONCLUSION: Administration of contrast material with a high iodine concentration is more effective for depicting pancreatic adenocarcinomas.