CT of the mesenteric vascular anatomy

Background: To evaluate the appearance of the arrangement of the superior mesenteric artery (SMA) and superior mesenteric vein (SMV) on computed tomography (CT) in normal patients and in patients with abdominal masses. Methods: One hundred seventy-seven consecutive abdominal CT examinations of 143 adults and two children were reviewed. The relationship of the SMV to the SMA was recorded at four locations: the beginning of the mesenteric vessels and levels 3 cm, 6 cm, and 9 cm caudad to the beginning. The relationship of the SMV to the SMA was divided into four quadrants in relation to the SMA: I, ventral right or directly ventral; II, dorsal right or directly right; III, dorsal left or directly dorsal; and IV, ventral left or directly left. Results: In the beginning of the SMV–SMA complex and levels 3 cm, 6 cm, and 9 cm caudal to the beginning, the SMV was located in quadrant I in 146, 84, 69, and 43 examinations, in quadrant II in 31, 93, 71, and 27 examinations, in quadrant III in zero, zero, five, and three examinations, and in quadrant IV in zero, zero, nine, and 15 examinations, respectively. The cases with SMV inversion had neither malrotation nor adjacent tumor compression. All the cases with an adjacent tumor-induced compression of the SMV–SMA complex had a normal SMV–SMA relationship. Conclusion: In the first 3 cm, the SMV is always to the right of the SMA. Caudal to the level of 6 cm, the SMV may be located to the left of the SMA without evidence of malrotation. A midgut nonrotation is more likely to be present when a proximal SMV inversion is coexistent with a rightward direction of the proximal jejunal vessels. A hypothetical depiction of the step-by-step change of the SMV–SMA relationship during embryologic development may explain the arrangement patterns of the mesenteric vessels in normal rotation and midgut nonrotation. Received: 6 May 1996/Accepted: 22 May 1996     

Pancreatic lesions and transfascial perirenal spread: Computed tomographic demonstration

Computed tomographic (CT) findings in 105 cases of pancreatitis and 107 cases of pancreatic carcinoma were analyzed retrospectively to determine the occurrence and roentgenologic signs of penetration of the anterior renal fascial planes in relation to clinical symptoms. In pancreatitis, the perirenal fat was infiltrated in 7% to variable extents by extrapancreatic fluid collections, either as asymptomatic fluid lying alongside renal fascial planes and perirenal septa (5 cases) or as well-circumscribed fluid collections causing clinical symptoms (2 cases). In pancreatic carcinoma the occurrence of retropancreatic extension to a perirenal space was rarer (3%). Distinction on CT between perirenal involvement from the pancreas and primary adrenal or renal lesions with anterior spread can prevent unnecessary surgery.     

Helical CT anatomy of pancreatic arteries

Background: To assess the frequency of visualization of pancreatic arteries in the arterial phase of helical computed tomography (CT). Methods: The visibility of pancreatic and peripancreatic arteries in helical CT images was evaluated in 20 consecutive patients who had no evidence of pancreatic disease. CT examinations were performed by using a continuously rotating CT scanner and intravenous injection of contrast media. The scans were taken 35 s after the start of injection and with a table speed of 3 mm/s. Images were reconstructed in 3-mm section increments. Results: Frequently visualized arteries were the gastroduodenal, anterior and posterior superior pancreaticoduodenal, and right gastroepiploic arteries. Infrequently visualized arteries were the dorsal pancreatic, pancreatica magna, caudal pancreatic, transverse pancreatic, and common, anterior, and posterior inferior pancreaticoduodenal arteries. Conclusion: Helical CT enabled us to recognize small pancreatic arteries, and the evaluation of these arteries should be considered in the staging of pancreatic carcinoma. Received: 6 June 1995/Accepted: 22 July 1995     

CT评价急性胰腺炎疗效一个新指标: 肠系膜上动脉与静脉比值

本文通过用双螺旋ＣＴ扫描，测量ＳＭＡ（ＳｕｐｅｒｉｏｒＭｅｓｅｎｔｅｒｉｃＡｒｔｅｒｙ）和ＳＭＶ（Ｓｕｐｅ－ｒｉｏｒＭｅｓｅｎｔｅｒｉｃＶｅｉｎ）的直径，ＳＭＡ直径测量恰好在ＳＭＡ的起始部，ＳＭＶ直径测量恰好在ＳＭＶ与门静脉汇合前。计算２０例急性胰腺炎治疗前后ＳＭＡ／ＡＭＶ的值。治疗后ＳＭＡ／ＳＭＶ的值均比治疗前的增大。结论是：有效治疗后ＳＭＡ／ＳＭＶ的值是评价急性胰腺炎疗效一个有效的新指标。     

Perirenal fat necrosis secondary to hemorrhagic pancreatitis,mimicking retroperitoneal liposarcoma: CT manifestation

A case of resolving hemorrhagic pancreatitis resulting in massive left perirenal fat necrosis is reported. CT revealed a huge fat-containing mass that was thought to be retroperitoneal liposarcoma before operation. Pancreatitis with perirenal involvement is rarely encountered as a retroperitoneal mass. Received: 27 September 1995/Accepted: 25 October 1995     

Detection of pancreatic adenocarcinoma: relative value of arterial and late phases of spiral CT

Background: Spiral computed tomography (CT) allows the pancreas to be imaged during peak contrast levels owing to the capability of fast data acquisition. The objective of this study was to evaluate the relative value of the arterial and late phases of spiral CT for detecting pancreatic adenocarcinomas. Methods: Twenty-two patients with pathologically proved pancreatic adenocarcinomas underwent two-phase spiral CT. The CT scans were performed with 5 mm collimation and 5 mm/s table speed. Images during the arterial and late phases were obtained at 30- and 180-second delays, respectively. The images of the arterial phase were compared with those of the late phase in terms of tumor conspicuity from surrounding pancreatic parenchyma and tumor detectability by means of a 3-point grading system: 1 (poor), 2 (fair), and 3 (good). Results: In terms of tumor conspicuity from surrounding pancreatic parenchyma, 16 lesions (73%) were good, 5 lesions (23%) were fair, and 1 lesion (4%) was poor during the arterial phase, whereas 6 lesions (27%) were good, 9 lesions (41%) were fair, and 7 lesions (32%) were poor during the late phase (p= 0.0007). The arterial phase was superior to the late phase in 16 patients (73%) and equal in 6 patients (27%). For tumor detectability, 18 lesions (82%) were good, 3 lesions (14%) were fair, and 1 lesion (4%) was poor during the arterial phase, whereas 10 lesions (45%) were good, 7 lesions (32%) were fair, and 5 lesions (23%) were poor during the late phase (p= 0.0033). For detectability, the arterial phase was superior to the late phase in 14 patients (64%) and equal in 8 patients (36%). Conclusion: The arterial phase of spiral CT is superior to the late phase, which is equivalent to conventional CT for detecting pancreatic adenocarcinoma. Received: 1 August 1995/Accepted: 12 September 1995     

Santorinicele in pancreas divisum: diagnosis with secretin-stimulated magnetic resonance pancreatography

A Santorinicele, or cystic dilatation of the dorsal pancreatic duct at the minor papilla, is seen in a small number of patients with pancreas divisum and may indicate obstruction at the minor papilla, a risk factor for pancreatitis. We present a case of a Santorinicele that was diagnosed with secretin-stimulated magnetic resonance pancreatography and treated with minor papillotomy. Received: 13 July 2000/Accepted: 23 August 2000     

Tumor-associated focal chronic pancreatitis from invasion of the pancreatic duct by common bile duct carcinoma: radiologic–pathologic correlation

We report a case of tumor-associated focal chronic pancreatitis of the uncinate process of the pancreas. The chronic pancreatitis was secondary to stenosis of the main pancreatic duct from invasion by a common bile duct carcinoma. A feature distinguishing the chronic pancreatitis from pancreatic carcinoma was the localized dilatation of pancreatic duct branches evident in the focal lesion of the uncinate process.     

Improved survival with early CT diagnosis of pancreatic abscess

Until recently pancreatic abscess was often a lethal complication of acute pancreatitis. A major factor contributing to this high mortality has been delay in diagnosis. When combined with diagnostic needle aspiration, computed tomography (CT) has greatly enhanced the early detection of pancreatic abscesses. In the past 5 years at our institutions 23 patients with proven pancreatic abscesses were evaluated early in their clinical course by CT. In follow-up ranging from 4 months to 4 1/2 years there were only 4 deaths: a mortality rate of 17%. Many of the surviving patients had a long and protracted clinical course (mean length of hospitalization, 58 days) and reoperation for recurrent abscess or gastrointestinal complications was required in 9 patients (39%). Computed tomography proved helpful both in localizing the site of de novo or recurrent pancreatic abscess and in detecting postoperative complications. An aggressive approach to early CT scanning with diagnostic needle aspiration appears to be a factor in the improved survival of these patients.     

Angiographic evaluation of the abnormal endoscopic pancreatogram

Out of 1,269 pancreatograms, 122 were abnormal. Angiography was performed in these patients. Fifty-five were found to have pancreatic carcinoma. In the remaining 67 patients a false positive angiographic diagnosis of either chronic pancreatitis or pancreatic cancer was made in 11%. In one patient a hemangioma was diagnosed as a pancreatic cyst. The remaining 58 patients all had normal pancreatic angiograms in spite of gross ductal abnormality on endoscopic retrograde cholangiopancreatography (ERCP). All these patients were followed for an average of 19 months and showed no clinical evidence of pancreatic disease. It is suggested that angiography should be considered a complementary examination to ERCP and is particularly useful to exclude carcinoma when the pancreatogram is abnormal.     

Lymphoepithelial cysts of the pancreas: CT and sonographic findings

Two cases of rare lymphoepithelial cyst (LEC) of the pancreas are presented. Although the histogenesis of this lesion is not known, it can be histologically differentiated from other pancreatic and retropancreatic cysts. The importance of its recognition is in the distinction from cystic neoplasm of the pancreas. Received: 24 October 1996/Accepted: 27 November 1996     

Vascular involvement in pancreatic adenocarcinoma:reassessment by thin-section CT

We defined computed tomographic (CT) criteria of vascular involvement by pancreatic carcinoma and used these criteria to assess vascular involvement in 56 patients with pancreatic adenocarcinoma. CT of the pancreas was performed at 1.5-mm section thickness and 5-mm section intervals during a bolus phase of intravenous contrast enhancement. The type of vascular involvement was correlated with surgical and pathologic findings. When there was fat-plane (type A) or normal pancreatic parenchyma (type B) separating the tumor from adjacent vessels, the tumor could be resected without venous resection in 21 of 22 patients (95%). When the tumor was inseparable from the vessels but the points of contact formed a convexity against the vessel (type C), CT was not reliable in predicting whether or not the tumor was fixed against the vessel. When the tumor was partially encircling (type D) the vessel, the tumor was fixed against the vessels in most cases. The resectable rate was 47%, but resection would also require venous resection. When the tumor was completely encircling (type E) or occluding (type F<+>) the vessel, all tumors were not resectable with a negative margin. Thin-section CT with bolus intravenous contrast enhancement improved the ability to assess vascular involvement in pancreatic adenocarcinoma. Received: 14 April 1995/Accepted: 12 June 1995     

Agenesis and pseudo-agenesis of the dorsal pancreas

Agenesis of the dorsal pancreatic anlage is a very unusual congenital anomaly. The case reported appears to be accompanied by hypertrophy of the ventral gland. Atrophy of the pancreas following an episode of acute pancreatitis is also very unusual. When the atrophy spares the uncinate process, it may also resemble agenesis of the dorsal gland.     

Heterotopic pancreas of the stomach: CT findings correlated with pathologic findings in six patients

Background: The purpose of this study was to characterize the computed tomographic (CT) findings of heterotopic pancreas of the stomach. Methods: CT scans of six surgically proven cases of heterotopic pancreas of the stomach were reviewed. Three were dynamic spiral CT scans, with both arterial dominant and late phase scans. In other three, both unenhanced and contrast-enhanced scans were obtained by using conventional techniques. Particular attention was given to the enhancement of the heterotopic pancreas. Pathologic and surgical findings were correlated with CT findings. Results: The locations were in the gastric antrum in five cases and in the mid-body in one. Size ranged from 1 cm to 3 cm (mean = 2.1 cm). Three cases showed homogeneous, strong enhancement similar to the pancreas and consisted mainly of pancreatic acini with the same histologic features as the normal pancreas. Two cases showed poor enhancement and consisted mainly of ducts and hypertrophied muscle; pancreatic acini were a minor component. In one case appearing as a cystic lesion on CT, a pseudocyst was found with many ducts and some nests of pancreatic acini. Conclusions: Heterotopic pancreas of the stomach showed a diverse spectrum of CT findings. Good understanding of these CT findings may be helpful in making a correct diagnosis. Received: 24 March 1999/Accepted: 19 May 1999     

Accuracy of endoscopic retrograde cholangiopancreatography (ERCP) in differentiating benign and malignant pancreatic disease

Despite advent of CT and ultrasound, endoscopic retrograde cholangiopancreatography (ERCP) remains useful in the preoperative evaluation of the pancreas. Using radiographic criteria previously described, ERCP was accurate in 90% of 71 patients in differentiating benign from malignant disease. Diagnostic errors were caused by chronic pancreatitis mimicking carcinoma (N=4) and carcinoma developing in a gland with chronic pancreatitis (N=3) missed on ERCP. Chronic pancreatitis was associated with a normal ERCP in 10% (N=4) of patients.     

Computed tomography and the dilated pancreatic duct: An ominous sign

The main pancreatic duct has been visualized with both ultrasound and computed tomography. A normal pancreatic duct has not been reported using CT, and controversy persists over whether a normal duct can be routinely imaged with ultrasound. The dilated pancreatic duct has always been associated with disease — usually pancreatitis or a proximal obstructing pancreatic carcinoma. In the patient with no clinical history or laboratory data suggesting pancreatitis, a dilated pancreatic duct implies a proximal tumor.     

Demonstration of false-negative findings on CT hepatic angiography

False-negative findings on CT angiography (CTA) in two patients with hepatocellular carcinoma (HCC) were demonstrated. CTA images of one patient with an aberrant left hepatic artery branching from the left gastric artery and another patient whose right hepatic artery was occluded owing to an unknown cause failed to demonstrate HCCs. This report suggests one of the diagnostic pitfalls of CTA for diagnosis of liver tumors. Received: 1 August 1995/Accepted: 12 September 1995     

Pitfalls in the echographic evaluation of pancreatic disease

Ultrasound has gained widespread acceptance in the evaluation of pancreatic disease. Echographic criteria for the diagnosis of pancreatitis, pseudocyst, and pancreatic carcinoma are presented. Additionally, three important areas of difficulty in the echographic evaluation of pancreatic disease are described.     

Asymptomatic nonspecific serum hyperamylasemia and hyperlipasemia: spectrum of MRCP findings and clinical implications

We assessed the magnetic resonance cholangiopancreatographic (MRCP) findings in patients with asymptomatic, mild elevations of serum amylase and lipase levels to determine whether there might be a pathoanatomic cause for these laboratory abnormalities. MRCP was performed in 633 consecutive patients. Of these, 54 (8.5%) images were obtained in patients with asymptomatic serum hyperamylasemia and hyperlipasemia. MRCP was performed on a 1.0-T MR system; breath-hold gradient-recall, half-Fourier acquisition, and rapid acquisition with relaxation enhancement sequences were obtained. Findings were verified by follow-up, biopsy, or surgery. One-sided, large-sample z tests were used to compare the incidence of abnormalities between the study and control groups (579 patients). The pancreas appeared abnormal on MRCP in 31 patients (57%), including the pancreas divisum in 10 patients (18.5%). Other findings included morphologic changes compatible with chronic pancreatitis in nine patients (16.6%) and a healed pancreatic laceration, juxtapapillary duodenal diverticulum, papillary sclerosis, intraductal pancreatic lithiasis, and hemochromatosis in one patient each (1.9%). Small cystic lesions (< 1 cm) within the pancreas were seen in 15 patients (27.8%). In eight patients, these were associated with other abnormalities (pancreas divisum in three patients, chronic pancreatitis in four, and pancreatic laceration in one). No malignancy was diagnosed. The incidences of normal examination (p = 0.01), pancreas divisum (p < 0.005), and a small cystic lesion (p = 0.01) as solitary findings in this subgroup of patients were significantly higher when compared with the remainder of the studied population. Investigation of asymptomatic patients with nonspecific hyperamylasemia and hyperlipasemia by means of MRCP yielded pancreatic findings in more than 50% of these patients. Pancreas divisum was found more often than expected in the general population.     

术前增强CT预测胰头癌侵犯肠系膜上静脉/门静脉

目的 评估术前增强CT预测胰头癌侵犯肠系膜上静脉(SMV)/门静脉(PV)及其程度的价值.方法 回顾性分析166例经病理证实的胰头(含钩突部)癌患者,评估术前门静脉期CT所示肿瘤直径、边界,肿瘤与静脉(SMV/PV)接触界面(TVI)(0/≤180°/>180°)、肿瘤与静脉(SMV/PV)接触长度(LIV),有无静脉...