Duodenal diverticulum mimicking a cystic pancreatic neoplasm.

Duodenal diverticula occur very commonly, with a prevalence as high as 22%. They are most frequently located in the second or third portions of the duodenum, and by nature of their proximity to the head of the pancreas, can be mistaken for cystic pancreatic neoplasms by diagnostic imaging. Patients with presumed cystic neoplasms of the pancreas often receive pancreaticoduodenectomies, which at high volume medical centres carry mortality and morbidity rates of 2-4% and 29-44%, respectively. Although most duodenal diverticula are recognized in single or repeat CT scans by the presence of air or contrast medium within the diverticula, we present a case in which serial CTs failed to yield any clue to the diverticulum's true nature and pancreaticoduodenectomy was performed. For presumed cystic lesions adjacent to the duodenum, barium studies, endoscopy, and/or endoscopic ultrasound-guided aspiration should therefore be pursued in addition to all available CT evidence prior to surgery.

The accuracy of CT staging of small bowel adenocarcinoma: CT/pathologic correlation.

PURPOSE: Several studies have documented the use of CT in the evaluation of small bowel neoplasms, but few have addressed the CT staging of adenocarcinoma. We retrospectively correlated CT and pathologic staging to evaluate the accuracy of CT for staging small bowel adenocarcinoma using American Joint Committee on Cancer criteria. METHOD: The preoperative CT scans of 15 patients with pathologically proven small bowel adenocarcinoma were analyzed. Two blinded readers separately interpreted extent of invasion, presence of lymphadenopathy, and distant metastases. Pathologic and CT staging were compared. RESULTS: The overall accuracy of CT staging was 47% (14/30). The sensitivity of detection of mesenteric infiltration was 88%. The sensitivity and specificity for detection of distant metastases were 58 and 63% and for lymphadenopathy 75 and 20%, respectively. Errors occurred in patients with Crohn disease, adenomas, Peutz-Jegher syndrome, small bowel obstruction, and perforation and on suboptimal studies. CONCLUSION: The accuracy of CT staging of small bowel adenocarcinoma is 47%. CT is highly sensitive but not specific for the detection of mesenteric infiltration and regional lymphadenopathy. Since spiral CT may offer improved detection of distant metastases and increased accuracy in the evaluation of patients with concomitant bowel disease, further research is needed to determine the maximal utility of CT in the staging of adenocarcinoma of the small bowel.

Potentially resectable pancreatic adenocarcinoma: spiral CT assessment with surgical and pathologic correlation.

PURPOSE: To evaluate the accuracy of spiral computed tomography (CT) in assessing the resectability of small pancreatic ductal adenocarcinoma and to correlate the CT findings with histopathologic and surgical findings. MATERIALS AND METHODS: Spiral CT scans obtained in 64 patients who underwent surgery for potentially resectable pancreatic adenocarcinoma were prospectively assessed for tumor resectability. CT findings were correlated with surgically assessed extent of tumor and pathologic findings. RESULTS: Fifty-seven (89%) of 64 carcinomas were detected with spiral CT. Twenty-four carcinomas were resectable at surgery and 40 were not. The average size of resectable tumors was 3.1 cm (range, 1.0-7.5 cm). The overall accuracy of spiral CT for assessing resectability was 70%. Of resected tumors, 14 were hypoattenuating compared with the remaining pancreas and 10 were isoattenuating. Eleven tumors showed neointimal proliferation in arterioles at histologic examination. CONCLUSION: Further progress in preoperative staging of pancreatic ductal adenocarcinoma with spiral CT should be directed toward improving detection of small pancreatic tumors and assessment of early metastatic disease.

Pulmonary nodules: effect of increased data sampling on detection with spiral CT and confidence in diagnosis.

PURPOSE: To compare spiral computed tomography (CT) with interscan spacing of 4-5 mm versus 8-10 mm for detection rate and level of confidence in diagnosis of pulmonary nodules. MATERIALS AND METHODS: Four radiologists (two junior and two senior faculty members) retrospectively reviewed 67 spiral CT studies with one to six nodules per study. Every second image was masked, which resulted in 8-mm sections every 8 or 10 mm; then all images reconstructed every 4 or 5 mm were reviewed. Lesions were classified as definite, probable, or possible. RESULTS: Narrow interscan spacing yielded more lesions overall (583 vs 566, P < .025) and more definite lesions and fewer equivocal lesions (482 vs 431 and 101 vs 135, respectively; P < .055). The greatest effects were in the reduction of possible lesions (50 vs 88, P < .001) and in the reduction of false-positive diagnoses made by less experienced radiologists. CONCLUSION: Increased reconstruction frequency of spiral CT volume data sets improves detection of pulmonary nodules and enhances confidence in the diagnosis.

CT of primary colonic lymphoma.

The article presents the computed tomography (CT) findings in 15 patients with histopathologically proven primary lymphoma of the colorectum. CT is invaluable for the characterization of primary colonic lymphomas and for definition of tumor invasion and spread. The lymphomas in our series were categorized according to their CT appearance as either discrete bulky masses (n = 6), focal mural infiltration (n = 5), or diffuse colonic invasion (n = 5). Primary colonic lymphomas that were manifested as mass lesions had a greater depth of mural invasion (x = 4.3 cm) than did infiltrative lesions (x = 2.7 cm, P < .05), and tended to present at an earlier stage. In the setting of solitary mass lesions in the colon that are not associated with adenopathy, CT findings can help to distinguish primary lymphoma from adenocarcinoma. Cecal tumors that grow into the terminal ileum, tumors which are fairly well demarcated from the surrounding pericolonic fat and show no evidence of invasion or obstruction of neighboring viscera, and tumors which perforate in the absence of desmoplastic reaction should suggest lymphoma. A clinical history of human immunodeficiency virus infection should also prompt consideration of colonic lymphoma.

CT findings in bronchiolitis obliterans organizing pneumonia (BOOP) with radiographic, clinical, and histologic correlation.

The CT features of 12 patients with bronchiolitis obliterans organizing pneumonia (BOOP) were reviewed and correlated with clinical history, histologic specimens, and chest radiography. From our series, a spectrum of CT findings of parenchymal lung involvement in BOOP emerged. Focal nodular or mass-like opacities were found in 42% (5 of 12). Areas of consolidation resembling pneumonia were seen in 33% (4 of 12). Peripheral subpleural reticular opacities were identified in 25% (3 of 12). Patchy ground glass infiltrates were seen in 8% (1 of 12). One patient demonstrated a mixed pattern consisting of nodular opacities and areas of pneumonic consolidation. In 4 of the 5 cases demonstrating the nodular form of BOOP either a feeding vessel or bronchus sign could be identified. This feature consisted of a pulmonary vessel leading to a nodular opacity or an air bronchogram entering into a nodular opacity. Correlation of the CT findings of BOOP with histologic specimens showed nodular opacities and areas of consolidation to be associated with classic pathologic features of BOOP including bronchiolar plugs of granulation tissue and surrounding organizing pneumonia. Cases demonstrating peripheral subpleural reticular opacities showed, in addition to pathologic evidence of BOOP, other features such as interstitial disease and fibrosis.

Detection of focal hepatic lesions with spiral CT: comparison of 4- and 8-mm interscan spacing.

OBJECTIVE: The objective of this study was to determine if spiral CT with 4-mm interscan spacing results in increased confidence in or rate of detection of focal hepatic lesions when compared with spiral CT with 8-mm interscan spacing. MATERIALS AND METHODS: Spiral CT scans of the liver of 42 consecutive patients with suspected hepatic disease were independently reviewed by three senior radiologists in two sets: one set was reconstructed with 8-mm interscan spacing and one set was reconstructed with 4-mm interscan spacing. The slice thickness was 8 mm for both data sets. The number and sizes of focal hepatic lesions were documented. RESULTS: Thirty-three of the 42 patients had least one focal lesion. The lesion size varied from 2 mm to 21 cm. When 8-mm interscan spacing was used, 297 lesions were detected (212 were considered definite). When 4-mm interscan spacing was used, 318 lesions were detected (258 were considered definite). Therefore, 7% more lesions were detected with 4-mm interscan spacing than with 8-mm interscan spacing (p = .05), and 22% more were diagnosed definitively (p < .01). If lesions larger than 4 cm are excluded, 10% more lesions were detected with 4-mm interscan spacing, and 33% more were diagnosed definitively. Of the lesions detected exclusively with 4-mm interscan spacing, 69% were less than 1.0 cm in diameter. CONCLUSION: Spiral CT with smaller interscan spacing (4 instead of 8 mm) results in increased confidence in and rate of detection of focal liver lesions. The additional benefit is most significant with smaller lesions.

Abnormal air-filled spaces in the lung.

The authors reviewed the radiographic and computed tomographic (CT) appearances of abnormal air-filled spaces in the lung that develop in response to lung diseases. The major types of these lung diseases include infection, vessel-related or vascular-embolic disorders, bronchiectasis, emphysema, pulmonary fibrosis, adult respiratory distress syndrome and air-block diseases, and unusual disorders of the lung (such as Langerhans cell histiocytosis, Klippel-Trenaunay syndrome, and tracheolaryngeal papillomatosis). After studying the CT scans, conventional radiographs, and medical records of 150 patients with various abnormal air-filled spaces in their lungs and 300 lung specimens and the corresponding high-resolution CT scans, the authors concluded that mechanisms of air-space formation fall into five basic categories: (a) vascular occlusion or ischemic necrosis, (b) dilatation of the bronchi, (c) disruption of the elastic fiber network of the lung, (d) remodeling of the lung architecture and retractile fibrosis, and (e) multifactorial or unknown mechanisms.

Spiral CT of the pancreas with multiplanar display.

This essay illustrates the findings obtained with spiral CT imaging in pancreatic disease. Features of spiral CT--fast scanning, dynamic injection of contrast material allowing optimal vessel opacification, and supplemental multiplanar imaging--promise to provide increased accuracy in the diagnosis and staging of pancreatic disease. With further development of continuous (spiral/helical) scanning technology, this technology should expand to cover a wider range of applications.

Pseudomembranous colitis: CT evaluation of 26 cases.

Pseudomembranous colitis (PMC) is an infectious colitis usually occurring as a complication of antibiotic use. The computed tomographic (CT) appearances of 26 patients with PMC were reviewed. Twenty-three patients demonstrated an abnormal bowel wall, with an average wall thickness of 14.7 mm (range, 3-32 mm); in three patients, bowel wall thickness was normal. Contrast material trapped between thickened folds corresponded to the broad transverse bands described on plain radiographs. Pancolonic involvement was seen in 13 cases, while seven patients had right-sided involvement only; three patients had bowel wall thickening limited to the rectosigmoid only. Although the CT appearance of PMC is not highly specific, the diagnosis may be suggested in the proper clinical setting.

Pneumocystis carinii pneumonia: spectrum of parenchymal CT findings.

Computed tomographic (CT) scans of the chest in 39 patients with Pneumocystis carinii pneumonia (PCP) were reviewed to determine the spectrum and frequency of CT manifestations of PCP. Parenchymal disease was categorized as either bilateral or unilateral, symmetric or asymmetric, and diffuse or patchy. Infiltrates were classified as interstitial, airspace, or mixed. On this basis, three CT patterns of involvement were identified: a ground-glass patchwork pattern in 22 of 39 (56%), and an interstitial pattern in seven of 39 patients (18%). Atypical CT features of PCP included nodules and nodular components in seven of 39 (18%) and cavities in three of 39 patients (8%). Associated CT findings included cystic spaces and bullae in 15 of 39 (38%), pneumothorax in five of 39 (13%), adenopathy in seven of 39 (18%), and pleural effusions in seven of 39 patients (18%). It is concluded that although PCP may exhibit a variety of CT appearances, certain patterns are more common than others. In the appropriate clinical setting, these findings are highly suggestive of PCP. The identification of cavities or nodular components in addition to infiltrates should raise the suspicion of a second disease process or mixed infection affecting the lungs.

Combined computerized tomography and angiography in the diagnosis of insulinoma.

We have presented a case of pancreatic insulinoma diagnosed by combined computerized tomography and angiography (CTA). In selected instances, CTA is preferable to dynamic enhanced CT in the detection of small pancreatic islet cell tumors.