Pancreatic pseudotumors: Computed tomography

Although pancreatic disease is suspected initially by historical or biochemical findings, the nature of the pathologic process in the past was frequently established only through invasive procedures. Inferences can be drawn from routine roentgenologic examinations, but visualization of the pancreas has only recently been achieved. Of the currently available noninvasive imaging procedures, computed tomography, in our opinion, is the screening procedure of choice. Care in the interpretation of pancreatic masses must be exercised since some of the findings can be attributed to anatomic variants, normal adjacent structures, or other neighboring pathologic processes.     

Computed tomography of intraperitoneal abscesses

Eighty-seven patients with the clinical suspicion of an intraperitoneal abscess were examined by computed tomography. In 83 of these patients CT gave true positive or true negative results in reference to the diagnosis of local intraperitoneal fluids. The final diagnosis confirmed 28 abscesses in 26 patients. Most of these abscesses were in the left subphrenic space, the right subphrenic space, the right anterior subhepatic space, and the pelvis. The morphological criteria for intraperitoneal abscesses, shown by CT, are defined. Direct signs include form, impression on nonintestinal organs, density value, gas collection, pyogenic membrane, and infiltration in surrounding tissue. Indirect signs include ascites and pleural effusion and/or pulmonary infiltration. Differential diagnostic problems of intraperitoneal abscesses are discussed.     

Demonstration of an internal pancreatic fistula by computed tomography

The computed tomographic demonstration of a mediastinal pseudocyst communicating with the pancreatic duct in a patient with severe acute pancreatitis is reported. An awareness of this communication was essential in planning the appropriate surgical management.     

Assessment of coronary artery bypass graft patency by multidetector computed tomography and electron-beam tomography

This case report describes the use of retrospectively ECG-gated 16-slice multidetector computed tomography (MDCT) and electron-beam tomography (EBT) for assessing bypass graft patency in two patients with recurrent angina after coronary artery bypass graft surgery. The results of each tomographic modality were compared to the findings of traditional coronary angiography. In the first patient MDCT showed occlusion of the left internal mammary artery (LIMA) and saphenous vein graft after the second anastomosis. Coronary angiography confirmed these findings. In the second patient EBT showed patency of the LIMA and saphenous vein graft. After the first anastomosis of the saphenous vein graft, the connected vessel filled poorly. Coronary angiography confirmed both grafts to be patent, and detected an occlusion distal to the first anastomosis. These findings support the evidence that both MDCT and EBT are suitable techniques for establishing bypass graft patency by non-invasive means.     

18F-前列腺特异性膜抗原-1007 PET/CT显像、11C-胆碱PET/CT显像及单光子发射计算机断层成像术骨显像对前列腺癌骨转移的诊断价值比较

目的探讨¹⁸F-前列腺特异性膜抗原(PSMA)-1007标记的正电子发射体层显像融合计算机体层显像技术(PET/CT)显像、11C-胆碱(11C-CHO)PET/CT显像及单光子发射计算机断层成像术(SPECT)骨显像在前列腺癌骨转移诊断上的差异。方法回顾性分析2018年9月至2020年7月北部战区总医院核医学科收治的43例男性前列腺癌患者的临床资料,年龄(77.47±11.87)岁,年龄范围为55~89岁。所有患者行¹⁸F-PSMA-1007 PET/CT显像、11C-CHO PET/CT显像及SPECT骨显像检查。分别统计¹⁸F-PSMA-1007 PET/CT显像、11C-CHO PET/CT及SPECT骨显像诊断骨转移的阳性例数和阴性例数,计算三种方法各自的灵敏度、特异度、准确性、阳性预测值、阴性预测值,绘制受试者工作特征(ROC)曲线,计算并比较各自曲线下面积(AUC),评价三种检查方法对前列腺癌骨转移的诊断效能。结果 43例前列腺癌患者中,27例患者出现骨转移。¹⁸F-PSMA-1007 PET/CT显像示26例患者发生骨转移,漏诊1例;11C-CHO PET/CT显像示24例患者发生骨转移,误诊1例,漏诊4例;SPECT骨显像示23例患者发生骨转移,误诊3例,漏诊7例,三者诊断前列腺癌骨转移的灵敏度、特异度、准确性分别为96.3%(26/27)、100%(16/16)、97.7%(42/43);85.2%(23/27)、93.8%(15/16)、88.4%(38/43);74.1%(20/27)、81.3%(13/16)、76.7%(33/43)。¹⁸F-PSMA-1007 PET/CT显像、11C-CHO PET/CT和SPECT骨显像ROC曲线的AUC和95%CI分别为0.981(0.885~1.000)、0.913(0.763~0.967)、0.777(0.624~0.889)。三种检查的AUC曲线下面积进行两两比较,差异均有统计学意义(P<0.05)。采用Wilcoxon秩和检验对27例患者三种方法检出的骨转移灶的数量进行两两比较发现,¹⁸F-PSMA-1007 PET/CT显像与SPECT骨显像比较,差异有统计学意义(Z=-2.484,P=0.013),¹⁸F-PSMA-1007 PET/CT显像与11C-CHO PET/CT显像比较,差异无统计学意义(Z=-0.160,P=0.873);11C-CHO PET/CT显像与SPECT骨显像比较,差异有统计学意义(Z=-2.085,P=0.037)。结论 PET/CT显像较SPECT骨显像能发现更多的骨转移灶。¹⁸F-PSMA-1007 PET/CT显像对前列腺癌骨转移诊断的灵敏度、特异度及准确性高于其他两种检查方式。在低前列腺特异性抗原(PSA)的情况下,能够精确地对前列腺癌骨转移做出诊断。     

正电子发射型断层成像在胃恶性肿瘤诊断中的作用

目的:评价正电子发射型断层扫描(PET)技术在胃恶性肿瘤中的诊断价值并与CT对照。方法:32例可疑胃恶性肿瘤患者术前行PET全身显像,22例行CT检查,将以上结果和病理分期对照。结果:32例中,25例为恶性肿瘤,7例为良性病变。18F-FDG-PET半定量分析对原发病灶的诊断敏感性、特异性分别为84%、5/7。CT对胃恶性肿瘤原发病灶诊断敏感性、特异性分别为88.9%和4/5。PET、CT对恶性肿瘤转移淋巴结检测准确率分别为80%和76.5%。PET、CT对远处转移病灶的诊断准确率分别为7/8和2/7。结论:PET对胃恶性肿瘤局部病灶和远处转移病灶检测较为敏感,在临床诊断有较高的应用价值。     

Computed tomography of bowel perforation

The authors present 2 cases of intestinal perforation which were not associated with free intraperitoneal air detectable on abdominal radiographs. Computed tomography demonstrated evidence of intraperitoneal leakage of orally administered contrast material and thereby provided the correct diagnosis.     

Computed tomography of gastrointestinal leiomyosarcoma

Computed tomography (CT) was performed in 6 patients with gastrointestinal leiomyosarcoma. The characteristic CT findings were a large extraluminal mass, apparently mesenteric in location, with central areas of necrosis. These findings were present in 5 of the 6 patients. Enhancement of the rim of the tumor was seen in 2 of 3 patients who had scans before and after administration of intravenous contrast material. CT identified the site of origin of tumor in only 2 patients. The characteristic CT findings should suggest the diagnosis of gastrointestinal leiomyosarcoma.     

Computed tomography of gastric lipomas

The computed tomographic manifestations of 2 cases of benign gastric lipoma are reported. Although conventional barium studies revealed the usual nonspecific appearances of submucosal tumors, their true fatty nature was easily demonstrated by computed tomography (CT). CT is a highly reliable noninvasive method for the diagnosis of gastric lipoma.     

Computed tomography and post-laparotomy intra-abdominal abscesses

Thirty-one patients were prospectively studied and had abdominal computed tomography for post laparotomy sepsis. Computed tomography is of particular interest in seriously ill post-operative patients, 15 of our patients were on ventilators, and it enabled diagnosis and localization of abscesses in 15 patients. Drainage could therefore be achieved via a limited surgical approach, and extensive laparotomy was avoided. Of 16 patients without abscess, the abdominal computed tomogram was negative in 14 cases and there were two false positives. The overall accuracy was 0.94 with a sensitivity of 1 and a specificity of 0.88. The ability to screen the whole abdomen and exactly localize the lesion are the advantages of this non-invasive method.Supported by grant no. 2375 from the Groupe de Recherches coopérative Université Paris-Val de Marne     

Sonography and computed tomography of macroscopic tuberculosis of the liver

Four patients with macronodular tuberculosis of the liver were examined with ultrasonography. The findings included 1 case with multiple hypoechoic areas and 3 cases with a solitary lesion, one hypoechoic mass without calcifications, and two partially calcified masses. Some ultrasound features are suggestive: a mass with irregular calcifications, ascites, spleen enlargement with defects, enlarged nodes, and complete resolution of the lesions in a few months with effective antituberculous therapy. The first case was also examinated with computed tomography.     

Computed tomography in complicated acute appendicitis

Due to the position and length of the appendix, intraabdominal abscesses after perforation in complicated acute appendicitis may occur in several different and sometimes unsuspected anatomical locations. Five patients are described with proven complicated acute appendicitis and inflammatory processes in multiple sites: anterior pararenal space, general retroperitoneum, subcutaneous fat space, intraperitoneal cavity, and small bowel mesentery. A confusing case of ileocecal carcinoid with mesenteric involvement is also presented.In all cases complicated acute appendicitis was diagnosed on CT prior to surgery, except in 1 case in which a pelvic abscess developed after intramural cecal bleeding in a patient with hemophilia B.     

Noninvasive coronary angiography using computed tomography

While noninvasive imaging of the coronary lumen remains challenging, great strides have been made with computed tomography. Two variations of computed tomography are used in the study of the coronary tree: multislice or multidetector computed tomography and electron-beam computed tomography. Both have high spatial and temporal resolutions as well as excellent signal-to-noise ratios, which allows major branches of the coronary tree to be depicted. Impaired image quality, due to dense calcifications and multiple image artifacts including coronary artery motion and breathing artifacts, limits the clinical utility of noninvasive coronary angiography. Early studies with electron-beam angiography demonstrated an overall sensitivity of 85% and specificity of 89% for the detection of obstructive coronary artery disease. With early diastolic imaging, the sensitivity and specificity increases to 92 and 93%, respectively (rather than 80% of the cardiac interbeat interval, where coronary motion is more pronounced). Multidetector computed tomography, with improved spatial resolution but decreased temporal resolution, produces results that vary depending on the equipment. Four-slice scanners have an average sensitivity of only 61%, and only 38% of patients have all four vessels or 15 segments available for analysis, due to both cardiac motion and calcification. Thinner slice collimation with eight and 16 slices have allowed for improved detection. Sensitivity and specificity improve to 80 and 86%, respectively. Furthermore, the number of assessable segments with eight-2011; to 16-2011;slice scanners improves significantly, compared with four-slice scanners (85 vs. 73%; p < 0.001). If only assessable segments are included in analysis, sensitivity and specificity for multidetector-row computed tomograpy improves to nearly 90%. Compared with magnetic resonance imaging, with a reported accuracy of 72% in the only multicenter study, computed tomography has great promise to become the primary method of noninvasive coronary angiography.     

Computed tomography of diverticulitis

Six cases of diverticulitis were studied by means of pelvic computed tomography (CT) and contrast enema. CT is effective in defining the intramural and extracolonic component of diverticulitis; abscess formation in the extracolonic space resulted in consistent changes in the contour of the opacified urinary bladder. Inflammatory extracolonic masses were imaged on CT as low or mixed-attenuation lesions frequently containing pockets of gas. Bladder wall thickening and edema, as well as contour asymmetry of the opacified and distended bladder, were reliable indicators of pericolonic or extracolonic extension of diverticular disease. Contrast enema and sigmoidoscopy are inherently limited in the evaluation of diverticulitis; CT of the pelvis reveals secondary changes outside the mucosa and bowel wall, CT directly images the inflammatory mass and associated changes in pelvic anatomic relationships.CT findings of pelvic inflammatory mass are not specific for abscess of diverticular origin; however, CT interpretation is reliable and confident since it is directed by the supporting findings on contrast enema. Integrated study by CT and contrast enema effectively defines the extent of disease in patients with diverticulitis. Summary evaluation of these studies has a serious impact on the choice of medical or surgical management.     

Computed tomography of adult ileocolic intussusception

Computed tomographic evaluation of ileocolic intussusception in an adult is presented. Upper gastrointestinal series with orally administered water-soluble contrast agent suggested obstruction in the lower part of the small intestine, but computed tomography made a definitive diagnosis. Pathognomonic CT findings of ileocolic intussusception are presented.     

Liver metastases from colorectal cancer: imaging with superparamagnetic iron oxide (SPIO)-enhanced MR imaging,computed tomography and positron emission tomography

The literature about superparamagnetic iron oxide-enhanced MR imaging, computed tomography (CT) and PET (positron emission tomography using fluorine-18 labelled fluoro-deoxy-glucose) in detection of liver metastases (LM) from colorectal cancer is reviewed in this update. Special emphasis is given to studies with surgical standard of reference allowing for the lesion-by-lesion sensitivity to be determined. Based on the review, it is concluded that state-of-the-art anatomical imaging, e.g., SPIO-enhanced MR imaging and multidetector CT (MDCT), must be considered more sensitive than PET in detection of individual LM, due to technical developments in MR imaging, such as liver specific contrast agents, modern sequences and high performance gradients, and in modern MDCT have increased the performance of these modalities. MR imaging with a liver specific contrast agent is recommended for the preoperative evaluation before liver surgery for LM because of high sensitivity and better discrimination between small LM and cysts compared to MDCT. PET or PET/CT can be used for detection of extra-hepatic tumor before liver surgery.