Multi--detector row helical CT of the pancreas: effect of contrast-enhanced multiphasic imaging on enhancement of the pancreas, peripancreatic vasculature, and pancreatic adenocarcinoma.

PURPOSE: To determine the optimal phase for enhancement of the normal pancreas and peripancreatic vasculature and the maximal tumor-to-pancreatic parenchymal enhancement difference by using multiphase, contrast material-enhanced, multi-detector row helical computed tomography (CT). MATERIALS AND METHODS: Forty-nine patients with a normal-appearing pancreas but suspected of having pancreatic abnormality and 28 patients with proved pancreatic adenocarcinoma underwent multiphase, contrast-enhanced, multi-detector row CT during the arterial phase (AP), pancreatic parenchymal phase (PPP), and portal venous phase (PVP). Attenuation values of the normal pancreas, pancreatic adenocarcinoma, celiac and superior mesenteric arteries, and superior mesenteric and portal veins were measured during all three imaging phases. Quantitative analysis of these measurements and subjective qualitative analysis of tumor conspicuity were performed. RESULTS: Maximal enhancement of the normal pancreatic parenchyma occurred during the PPP. Maximal tumor-to-parenchyma attenuation differences during the PPP and PVP were equivalent but greater than that during the AP. Subjective analysis revealed that tumor conspicuity during the PPP and PVP was equivalent but superior to that during the AP. Maximal arterial enhancement was seen during the PPP, and maximal venous enhancement was seen during the PVP. CONCLUSION: A combination of PPP and PVP imaging is sufficient for detection of pancreatic adenocarcinoma, because it provides maximal pancreatic parenchymal and peripancreatic vascular enhancement. AP imaging can be reserved for patients in whom CT angiography is required.     

Adenocarcinoma of the pancreatic ducts: comparative evaluation with CT and MR imaging at 1.5 T.

A prospective comparison of computed tomography (CT) and magnetic resonance (MR) imaging at 1.5 T was performed in 50 patients with the suspected diagnosis of pancreatic carcinoma. CT scans were obtained before and after administration of contrast material in 41 of 50 patients (82%); 34 of 41 postcontrast scans (83%) were obtained with dynamic CT. MR images were interpreted without knowledge of the results of CT, ultrasound, cholangiography, or endoscopic retrograde cholangiopancreatography in 48 patients (96%). Surgical correlation of findings at CT and MR imaging was performed in 24 patients (48%) at laparotomy and in two patients (4%) at autopsy. On T1-weighted MR images, relatively diminished signal intensity of tumor compared with that of the adjacent pancreas was a consistent finding. MR imaging proved superior to CT in identification of pancreatic carcinoma (particularly in smaller intrapancreatic tumors), peripancreatic extension, vascular and portal vein invasion, and duodenal invasion. These results suggest that MR imaging of the pancreas is superior in many instances to CT in preoperative evaluation of pancreatic carcinoma.     

Pancreatic-phase versus portal vein-phase helical CT of the pancreas: optimal temporal window for evaluation of pancreatic adenocarcinoma

OBJECTIVE: Our objective was to use helical CT to compare the enhancement attenuation values of pancreatic adenocarcinoma, adjacent normal pancreas, and critical vascular structures during the pancreatic phase and portal vein phase. SUBJECTS AND METHODS: Forty-one patients with pathologically proven pancreatic adenocarcinoma underwent dual-phase thin-section dynamic helical CT using a pancreatic-phase and portal vein-phase protocol. The scan delay after initiation of the contrast bolus was 40 sec for the pancreatic phase and 70 sec for the portal vein phase. Attenuation values after i.v. contrast administration were calculated during both phases of scanning for normal pancreas, pancreatic tumor, celiac axis, superior mesenteric artery, superior mesenteric vein, splenic vein, and portal vein. Quantitative values were assessed using regions of interest. RESULTS: Mean differences of enhancement between tumor and normal pancreas were significantly greater in the pancreatic phase (57 H) than the portal vein phase (35 H) (p = .0001). Enhancement values of all the critical vascular structures were also significantly greater in the pancreatic phase than the portal vein phase (p < .001). CONCLUSION: With dynamic thin-section helical CT, pancreatic-phase scanning provides greater differences in contrast enhancement between normal pancreas and pancreatic tumor and between pancreatic tumors and surrounding critical vascular structures than does portal vein-phase scanning.     

Diagnosis and staging of pancreatic cancer: comparison of mangafodipir trisodium-enhanced MR imaging and contrast-enhanced helical hydro-CT

OBJECTIVE: The purpose of this study was to compare mangafodipir trisodium-enhanced MR imaging performed with a phased array coil and contrast-enhanced single-detector helical CT for accuracy in the detection and local staging of pancreatic adenocarcinoma and in the differentiation between cancer and focal pancreatitis. SUBJECTS AND METHODS: Forty-two patients with suspected pancreatic masses underwent contrast-enhanced helical CT and mangafodipir trisodium-enhanced MR imaging at 1.5 T. The images were assessed for the presence or absence of tumors; characterization of masses; and presence of vascular invasion, lymph node metastases, or liver metastases. Imaging findings were correlated with findings at laparotomy, laparoscopy, biopsy, or follow-up. RESULTS: Focal masses were present in 36 patients (cancer, n = 26; focal pancreatitis, n = 7; other, n = 3). The sensitivity for lesion detection of MR imaging was 100% and of CT, 94%. Two small malignant lesions were missed on CT. For the diagnosis of tumor nonresectability, the sensitivity of MR imaging and CT was 90% and 80%, respectively. Liver metastases were missed on MR imaging in one of the eight patients and on CT in four. For differentiation between adenocarcinoma and nonadenocarcinoma, the sensitivity of MR imaging was 100% (positive predictive value, 90%; negative predictive value, 100%), and the sensitivity of CT was 92% (positive predictive value, 80%; negative predictive value, 67%). Receiver operating characteristic analysis revealed that the mean area under the curve for MR imaging was 0.920 and for CT, 0.832 (not significant). CONCLUSION: Mangafodipir trisodium-enhanced MR imaging is as accurate as contrast-enhanced helical CT for the detection and staging of pancreatic cancer but offers improved detection of small pancreatic metastases and of liver metastases compared with CT.     

Alterations in hepatic perfusion resulting from splanchnic venous luminal compromise caused by pancreatic carcinoma

OBJECTIVE: We determined whether alterations in hepatic enhancement exist on dual phase helical CT of the liver in patients with splanchnic venous luminal compromise resulting from pancreatic adenocarcinoma. SUBJECTS AND METHODS: We examined the extent of hepatic enhancement on dual phase helical CT in 22 patients with pancreatic adenocarcinoma. Eleven patients had splanchnic venous luminal narrowing (flattening along at least 120 degrees of the circumference) of the superior mesenteric vein with (n = 3) or without (n = 8) portal vein involvement caused by tumor. In the remaining patients, splanchnic vasculature appeared normal. An additional 16 patients without pancreatic or hepatic abnormality who underwent dual phase helical CT served as control subjects. We compared the extent of arterial phase and portal venous phase enhancement among the three groups. RESULTS: The group of patients with splanchnic venous luminal compromise had significantly higher hepatic enhancement during the arterial phase (p < 0.01) and lower enhancement during the portal venous phase (p < 0.05) compared with the other two groups of patients. No significant difference in hepatic enhancement during either phase was noted between the control subjects and the patients with normal vasculature. CONCLUSION: Because hepatic enhancement correlates with perfusion, splanchnic venous luminal compromise resulting from pancreatic adenocarcinoma likely causes decreased portal venous flow and compensatory increased hepatic arterial flow. This finding supports other evidence of a homeostatic mechanism that maintains hepatic perfusion.     

Pancreatic portal cavernoma in patients with cavernous transformation of the portal vein: MR findings

The purpose of the article was to prospectively evaluate the MR findings of pancreatic portal cavernoma in a consecutive series of patients with cavernous transformation of the portal vein. This study was approved by the review board of our institution, and informed consent was obtained. The clinical and biological data and the MR imaging for 20 patients (11 female, 9 male; median age, 49 years) with cavernous transformation of the portal vein and no evidence of previous pancreatic disease were reviewed. The presence of pancreatic portal cavernoma (defined as intra- and/or peripancreatic portal cavernoma), morphological changes in the pancreas, biliary and ductal pancreatic abnormalities, and extension of the portal venous thrombosis were qualitatively assessed. Fifteen patients (75%) had pancreatic portal cavernoma with collateral formation in the pancreas and/or collaterals around the pancreas seen on dynamic contrast-enhanced MR sequences: three patients had both intra- and peripancreatic portal cavernoma, six had intrapancreatic portal cavernoma alone and six had peripancreatic portal cavernoma only. The presence of intra- or peripancreatic portal cavernoma was significantly associated with extension of the thrombosis to the splenic and superior mesenteric veins (p = 0.05). Morphological changes in the pancreas, heterogeneity on T2-weighted sequences and main ductal pancreatic abnormalities were seen in two, four and two patients, respectively. All these patients had intrapancreatic portal cavernoma. Bile duct dilatation was observed in 13 (65%) patients: among them three had extrahepatic dilatation only and these three patients had associated intrapancreatic portal cavernoma. In patients with cavernous transformation of the portal vein, intra- or peripancreatic portal cavernoma is common. In conclusion, intra- or peripancreatic portal cavernoma was only observed in patients with extension of the thrombosis to the splenic vein and/or the superior mesenteric vein.     

Pancreatic carcinoma: MR, MR angiography and dynamic helical CT in the evaluation of vascular invasion

OBJECTIVE: To assess the value of MR angiography in combination with contrast-enhanced MR imaging, and to compare MR imaging including MR angiography with dynamic contrast-enhanced dual phase helical CT in the preoperative assessment of vascular invasion in patients with suspected pancreatic carcinoma. METHODS AND MATERIAL: MR imaging only, MR imaging including MR angiography and dynamic contrast-enhanced dual phase helical CT images of 48 patients who were operated due to suspicion of pancreas cancer were correlated with the surgery results in terms of vascular invasion. Pathologic diagnosis were pancreatic adenocarcinoma in 31 patients of which nine had surgically confirmed vascular invasion. Sensitivity, specificity, predictive values (including 95% confidence intervals) and accuracy of MR imaging only, MR imaging including MR angiography and helical CT were calculated. RESULTS: Sensitivity, specificity, positive and negative predictive values and accuracy were 56, 100, 100, 85, 87%; 67, 100, 100, 88, 90% and 67, 100, 100, 88, 90%, respectively, for MR imaging only, MR imaging including MR angiography and helical CT in the adenocarcinoma group. The corresponding figures in the overall study group were 56, 97, 83, 90, 90%; 67, 97, 86, 93, 92% and 67, 97, 86, 93, 92%. Confidence intervals (95%) showed that the differences in the diagnostic efficacy of the techniques were not statistically significant in the overall study group, but the confidence intervals were undefined in the adenocarcinoma group due to the small sample size. CONCLUSION: Diagnostic efficacy of MR imaging when combined with MR angiography is equal to that of dynamic contrast-enhanced dual phase helical CT in the assessment of vascular invasion of pancreatic tumors.     

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.     

Dynamic CT of pancreatic tumors

Dynamic computed tomography was performed on 19 patients with clinically diagnosed pancreatic and peripancreatic tumors. There were 10 patients with pancreatic cancer, three with inflammatory pancreatic masses, two with cystadenoma, one with insulinoma, and three with peripancreatic tumors. Computed tomography was performed with a Varian-V-360-3 scanner; scanning was for 30 consecutive sec at 3 sec intervals after the bolus injection of 50 ml of contrast medium into the antecubital vein. Dynamic computed tomography (CT) may be more useful than conventional contrast CT because it facilitates: (1) correct evaluation of tumor vascularity allowing a differential diagnosis; (2) location of the boundary between tumor and a nontumor tissue; (3) detection of small tumors; and (4) visualization of pancreatic invasion by peripancreatic tumors. In addition, contrast enhancement and the degree of vascular proliferation can be quantitatively assessed by analyzing time-density curves.     

Adenocarcinoma of the head of the pancreas: determination of surgical unresectability with thin-section pancreatic-phase helical CT

OBJECTIVE: This study was conducted to evaluate newly introduced criteria for unresectability of pancreatic cancer with thin-section pancreatic-phase helical CT. MATERIALS AND METHODS: Twenty-five patients with adenocarcinoma in the head of the pancreas underwent thin-section pancreatic-phase helical CT. The major peripancreatic vessels were categorized on a scale of 1-4, according to the degree of circumferential involvement by tumor. The maximum diameters of the small peripancreatic veins--gastrocolic trunk, anterosuperior pancreaticoduodenal vein, and posterosuperior pancreaticoduodenal vein--were recorded. Findings on CT were compared with the results of surgery in each patient. RESULTS: Sixteen patients had surgically resectable tumors, and nine patients had surgically unresectable tumors. CT and surgical correlation was available for 98 major peripancreatic vessels; 85 were resectable and 13 were unresectable. Of category 1 vessels, 72 (97%) of 74 were resectable at surgery. Of category 2 vessels, 12 (71%) of 17 were resectable. One (50%) of two category 3 vessels and none (0%) of five category 4 vessels were resectable at surgery. CT showed a dilated gastrocolic trunk in two patients; one of these patients had a surgically resectable tumor, but the other patient had a surgically unresectable tumor. CONCLUSION: In patients with adenocarcinoma in the head of the pancreas, the degree of circumferential vessel involvement by tumor as shown by CT is useful in predicting which patients will have surgically unresectable tumors. A dilated gastrocolic trunk should not be used as an independent sign of surgical unresectability.     

胰腺癌血管侵犯的不同CT诊断标准的研究

目的:研究胰腺癌血管侵犯的不同CT诊断标准的优劣。材料和方法:回顾性收集我院经多层螺旋CT三期动态增强扫描并经手术病理证实为胰腺导管细胞癌的36例患者。CT轴位图像结合CTA(以MIP和VR方法重建)以及多平面重建(MPR)分别对这些血管以Loyer和Lu血管分级CT标准进行分级,并和手术结果进行对照,分别作出受试者工作特性曲线(ROC),比较曲线下面积的差异。另外,运用Lu的CT诊断标准分别评价胰周动脉和静脉受侵的准确性、灵敏度、特异度、阳性预测值、阴性预测值、Youden指数,研究Lu的CT诊断标准对动静脉分级的差异。结果:Loyer和Lu的CT诊断标准所得的灵敏度、特异度分别为84.5%、86.0%、81.4%、91.8%,两个诊断标准的ROC曲线下面积分别为0.886、0.912,经统计学检验无明显差异。应用Lu的CT诊断标准,胰周动静脉受侵的阳性预测值分别为57.1%和71.0%。结论:分别以Loyer和Lu血管分级CT标准对胰腺癌胰周血管侵犯进行分级,两者的诊断价值相同,Lu的CT诊断标准的最佳诊断分界点应在90°-180°之间,此外,它对胰周动脉的价值要比静脉差。     

CT assessment of the inferior peripancreatic veins: clinical significance

OBJECTIVE: The purpose of this study was to evaluate and clarify the clinical significance of CT scans of the inferior peripancreatic veins. MATERIALS AND METHODS: Forty-three patients with suspected pancreatic disease underwent three-phase helical CT (collimation, 5 mm; reconstruction, 2.5 mm; scan delay, 30, 60, and 150 sec). The frequency of visualization on CT of the anterior and posterior inferior pancreaticoduodenal veins, inferior pancreaticoduodenal vein, and first jejunal trunk was assessed and correlated with angiographic and pathologic findings. RESULTS: The frequency of visualization of normal inferior peripancreatic veins in patients (n = 22) with a normal portomesenteric vein was 36% for the anteroinferior pancreaticoduodenal vein, 36% for the posteroinferior pancreaticoduodenal vein, 59% for the inferior pancreaticoduodenal vein, and 100% for the first jejunal trunk. The smaller inferior peripancreatic veins were frequently not visualized when normal. In patients (n = 13) with pancreatic carcinoma involving the portosuperior mesenteric vein, all of the inferior peripancreatic veins were dilated and easily recognizable. When the tumor did not involve the portosuperior mesenteric vein but did involve the anteroinferior pancreaticoduodenal, posteroinferior pancreaticoduodenal, and inferior pancreaticoduodenal veins (n = 8), some of the other peripancreatic veins (first jejunal trunk, anterior and posterior superior pancreaticoduodenal veins, and gastrocolic trunk) were dilated. Dilatation indicated tumor extension to the third portion of the duodenum. In patients (n = 7) with involvement of the inferior pancreaticoduodenal vein, the first jejunal trunk, or both without the involvement of the portosuperior mesenteric vein, dilatation of the other peripancreatic veins (anteroinferior pancreaticoduodenal vein, posteroinferior pancreaticoduodenal vein, anterosuperior pancreaticoduodenal vein, posterosuperior pancreaticoduodenal vein, and gastrocolic trunk) indicated tumor invasion of only the second portion of the extrapancreatic nerve plexus (n = 4) and tumor invasion of both the second portion of the extrapancreatic nerve and the mesenteric root (n = 3). CONCLUSION: Dilatation of peripancreatic veins with nonvisualization of inferior peripancreatic veins suggests tumor invasion of peripancreatic tissue.     

Dual-phase helical CT of pancreatic adenocarcinoma: assessment of resectability before surgery

OBJECTIVE: The aim of our study was to prospectively evaluate the accuracy of dual-phase helical CT in the preoperative assessment of resectability in patients with suspected pancreatic cancer using surgical and histopathologic correlation. SUBJECTS AND METHODS: Between January 1999 and December 2000, 76 patients with suspected pancreatic cancer underwent preoperative evaluation and staging with dual-phase helical CT (3-mm collimation for pancreatic phase, 5-mm collimation for portal phase). Iodinated contrast material was injected IV (170 mL at a rate of 4 mL/sec); acquisition began at 40 sec during the pancreatic phase and at 70 sec during the portal phase. Three radiologists prospectively evaluated the imaging findings to determine the presence of pancreatic tumor and signs of unresectability (liver metastasis, vascular encasement, or regional lymph nodes metastasis). The degree of tumor-vessel contiguity was recorded for each patient (no contiguity with tumor, contiguity of < 50%, or contiguity of > or =50%). RESULTS: Thirty-nine patients with pancreatic adenocarcinoma were surgically explored. Curative resections were attempted in 34 patients and were successful in 25. The positive predictive value for resectability was 73.5%. Nine patients considered resectable on the basis of CT findings were found to be unresectable at surgery because of liver metastasis (n = 5), vascular encasement (n = 2), or lymph node metastasis (n = 2). We found that the overall accuracy of helical CT as a tool for determining whether a pancreatic adenocarcinoma was resectable was 77% (30/39 patients). CONCLUSION: Dual-phase helical CT is a useful technique for preoperative staging of pancreatic cancer. The main limitation of CT is that it may not reveal small hepatic metastases.     

(18)F-FDG PET/CT for discrimination between tumor extension and blood thrombus in pancreatic adenocarcinoma associated with portal vein thrombosis

Pancreatic cancer is a malignancy with an extremely poor prognosis. Less than 3 % of patients are alive 5 years after diagnosis. Pancreatic neoplasms represent a possible but uncommon etiology of portal venous invasion. It is important to differentiate the nature of the thrombus, if it is a bland thrombus or is a direct tumor extension. Intense uptake of 18F-fluorodeoxyglucose ((18)F-FDG) has been reported in portal vein tumor thrombus. We present a case of pancreatic adenocarcinoma and clinical findings of portal hypertension due to portal vein thrombosis. (18)F-FDG positron emission tomography (PET)/computed tomography (CT) evaluation discarded a tumor thrombus; imaging findings of the pancreatic tumor and the bland thrombus are presented.     

Efficacy of three-dimensional fast imaging with steady precession dynamic MR imaging in evaluating pancreatic ductal adenocarcinoma.

To compare the diagnostic efficacy of three-dimensional fast imaging with steady precession (3D-FISP) dynamic MR imaging in assessing pancreatic ductal adenocarcinoma with conventional MR imaging and helical CT, 15 patients with surgically proven pancreatic ductal adenocarcinoma were studied. Contrast-to-noise ratio (CNR) of the tumor, tumor detectability, local tumor extension, and vascular involvement were evaluated for all techniques. The results indicate that 3D-FISP dynamic MR imaging may improve the imaging assessment of pancreatic ductal adenocarcinoma.     

多层螺旋CT多期增强扫描及后处理对胰岛素瘤的评价

目的:探讨多层螺旋CT(MSCT)多期扫描及后处理对胰岛素瘤检出的价值。方法:13例手术证实的胰岛素瘤均行MSCT平扫及三期增强扫描,观察各期肿瘤增强程度及检出率。结果:13例CT平扫肿瘤均为等密度,动脉期及门脉期肿瘤与胰腺实质密度差为24HU与29HU,动脉期、门脉期及实质期肿瘤的检出率分别为84%、100%及62%。结论:MSCT多期成像对胰岛素瘤诊断具有重要价值,门脉期在检出肿瘤方面略优于动脉期扫描,MSCT薄层扫描及其后处理技术有助于显示肿瘤的空间位置及其与血管的关系。     

Pancreatic mass due to chronic pancreatitis: correlation of CT and MR imaging features with pathologic findings.

OBJECTIVE: The purpose of this study was to identify helical CT and MR imaging features of pancreatic masses (focal enlargement) due to chronic pancreatitis and their correlation with pathologic findings. CONCLUSION: When histologic fibrosis is uniformly present through the pancreas in patients with chronic pancreatitis, there is no demarcation of masses due to chronic pancreatitis. When there is a greater degree of histologic fibrosis in the masslike part of the pancreas, the mass is often demarcated from the remaining pancreas, and the enhancement pattern on two-phase helical CT and dynamic gadolinium-enhanced MR imaging mimics that of pancreatic adenocarcinoma.     

胰腺癌胰周淋巴结转移分布特征的螺旋CT表现

目的:胰腺癌胰周淋巴结转移的分布特征及螺旋CT影像表现。方法:搜集经手术病理诊断为原发性胰腺癌45例,所有病例均经手术病理或影像标准诊断有胰周淋巴结转移。根据本组45例病例CT所反映的肿大淋巴结的分布情况,将胰周淋巴结分为8组。设定淋巴结的短径≥1.0cm为淋巴结转移阳性的影像表现。统计阳性淋巴结的出现率,重点观察淋巴结转移的部位、大小、数目、形态、密度、强化情况。结果:本组45例胰腺癌中,共计89个部位观察到淋巴结转移胰周转移淋巴结以腹腔动脉干组46.7%(21例),肠系膜根部组46.7%(21例),腹主动脉周围组35.6%(16例)为最多,胃周11.1%(5例)及脾动脉-脾门组13.3%(6例)最少。结论:胰腺癌转移所致肿大淋巴结主要分布在腹腔干、肠系膜根部以及腹主动脉周围。螺旋CT扫描检查可以较准确显示胰腺癌胰周淋巴结的转移情况。     

Septic thrombosis of the portal vein due to peripancreatic ligamental abscess

Septic thrombus formation of both the main portal vein and its intrahepatic branches were observed on CT in a patient with peripancreatic abscess. The septic thrombosis of portal vein (STPV) extended from the level of porta hepatis into the intrahepatic branches, but the portal vein and superior mesenteric vein at the level of pancreatic head were preserved with no evidence of thrombosis angiographically. The gas-containing abscess near the head of the pancreas extended toward the hepatic hilum and surrounded the portal vein and its branches on CT. It was concluded that these thrombi of portal vein branches at porta hepatis and intrahepatic branches were caused by extensions of peripancreatic abscess via the hepatoduodenal ligament and ligamentum teres. Computed tomography was useful in depicting the ligamentous spread of peripancreatic abscess resulting in STPV. Received: 29 September 1997; Revision received: 13 February 1998; Accepted: 16 February 1998     

胰腺癌:MRI检查技术和诊断

胰腺癌的患病率呈上升趋势。更重要的是胰腺癌早期没有症状，恶性程度高，发展快，侵及范围广，病死率高。外科手术切除是胰腺癌治疗的有效手段，胰腺癌的检测和分期是MRI的重要课题。近年来，MRI技术的发展可以较全面地评价胰腺及胰腺病变，这些技术包括屏气T1加权成像及其脂肪抑制，T2加以成像及其抑制、Gd-DTPA,动态增强、MRCP和MRA，这些脉冲序列各自有其不同的组织对比机制，而且是相互补充的。其中Gd-DTPA动态增强MRI是检测胰腺癌最可靠，应用最广的技术，它们的联合应用，在检测胰腺癌，特别是局限于胰腺内的小部肿，优于螺旋CT；在胰腺癌的分期中，动态增强MRI在确定肿瘤的局部侵犯和肝转移上优于螺旋CT，对血管的侵犯的判断两者相似。