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BACKGROUND: The usefulness of currently available colon imaging tests, including air contrast barium enema (ACBE), computed tomographic colonography (CTC), and colonoscopy, to detect colon polyps and cancers is uncertain. We aimed to assess the sensitivity of these three imaging tests. METHODS: Patients with faecal occult blood, haematochezia, iron-deficiency anaemia, or a family history of colon cancer underwent three separate colon-imaging studies--ACBE, followed 7-14 days later by CTC and colonoscopy on the same day. The primary outcome was detection of colonic polyps and cancers. Outcomes were assessed by building an aggregate view of the colon, taking into account results of all three tests. FINDINGS: 614 patients completed all three imaging tests. When analysed on a per-patient basis, for lesions 10 mm or larger in size (n=63), the sensitivity of ACBE was 48% (95% CI 35-61), CTC 59% (46-71, p=0.1083 for CTC vs ACBE), and colonoscopy 98% (91-100, p<0.0001 for colonoscopy vs CTC). For lesions 6-9 mm in size (n=116), sensitivity was 35% for ACBE (27-45), 51% for CTC (41-60, p=0.0080 for CTC vs ACBE), and 99% for colonoscopy (95-100, p<0.0001 for colonoscopy vs CTC). For lesions of 10 mm or larger in size, the specificity was greater for colonoscopy (0.996) than for either ACBE (0.90) or CTC (0.96) and declined for ACBE and CTC when smaller lesions were considered. INTERPRETATION: Colonoscopy was more sensitive than other tests, as currently undertaken, for detection of colonic polyps and cancers. These data have important implications for diagnostic use of colon imaging tests.

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To determine prospectively the value of prone/postprone positioning in the sonographic detection of gallstones, 682 patients were scanned in the recumbent, erect, and prone or postprone positions. The gallbladder was evaluated for an intraluminal hyperechoic focus, shadowing, and gravitational dependence and was identified in 679 patients. Among these, 28% had cholelithiasis. In five cases, prone positioning alone revealed gallstones. In 11 of 140 cases, gravitational dependence was only seen with prone scanning. The gallbladder was seen more frequently when the patients were prone than erect. Prone or postprone scanning is a useful supplement to the gallbladder examination, allowing increased demonstration of gravitational dependence and increased stone detection.

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There are several forms of emphysema that should be considered as distinct disease entities. No university accepted classification system of these forms exists, but correlations of autopsy findings in 1,823 cases over a 12-year period confirm that the radiographic and pathologic features of the emphysemas are readily understood when centrilobular, panlobular, paracicatricial, and localized types of the disease are recognized. Centrilobular emphysema associated with cigarette smoking is the most common form. Panlobular emphysema is associated with alpha 1-protease inhibitor deficiency and pathologically produces uniform enlargement of all air spaces, with a mild basilar predominance. Paracicatricial emphysema is seen adjacent to areas of parenchymal scarring. Localized emphysema represents focal enlargement or destruction of air spaces with otherwise normal lung. A clear understanding of the computed tomographic appearance of all forms of emphysema is essential for the correct diagnosis of parenchymal lung abnormalities.

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Bronchography is seldom recommended today to localize radiographically and bronchoscopically occult bronchogenic carcinoma. We report a case in which bronchography promptly localized such a tumor that had been occult to multiple bronchoscopies and chest computed tomograms (CTs). The patient is free of recurrence 32 months after lobectomy. Bronchography should be considered when bronchoscopies and CT fail to reveal a radiographically occult carcinoma.

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Nine small renal masses with attenuation coefficients greater than 20 HU on computed tomography (CT) were termed indeterminate for cyst or renal cell carcinoma. Correlative sonography identified the fluid-filled internal architecture in four of five cysts and correctly characterized as solid four small renal cell carcinomas. The sonogram was particularly valuable in assessing masses that were indeterminate on CT when enhancement was equivocal or when intravenous contrast could not be administered. We conclude that sonography is extremely useful as a noninvasive procedure in evaluating the occasional small renal mass with CT number greater than 20 HU.

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The imaging studies of 63 patients with hepatic abscess were evaluated to determine the sensitivity of specific imaging tests and define causes of false-negative test results. Computed tomography (CT) detected 57 of 59 (97%) separate episodes of hepatic abscess. The two false-negative CT examinations were in patients with a diffuse low-density pattern throughout the liver. The radionuclide (RN) examination detected 16 of 20 (80%) cases, missing abscesses less than 2 cm in diameter. Ultrasound detected 33 of 42 (79%) cases, missing abscesses in the dome of the liver, small abscesses, and 2 large early abscesses. For all three imaging modalities, a specific diagnosis of abscess was possible only in those patients in whom CT scans demonstrated abscess gas (15%). The results of the imaging studies were correlated with the patients' clinical condition and laboratory findings. Thirty-one percent of patients were afebrile while 23% had normal white blood cell counts. Thirteen percent had totally normal liver function tests. We conclude that the clinical absence of fever, leukocytosis, or elevated liver function tests does not permit exclusion of the diagnosis of hepatic abscess. A CT scan is highly specific in excluding the diagnosis of hepatic abscess in the absence of diffuse liver disease. In this retrospective study CT was the most sensitive imaging modality available for the detection of hepatic abscess.

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CT is an important diagnostic procedure in patients with suspected or known disease of the rectum. Knowledge of proper technique for CT of the rectum, as well as an understanding of normal pelvic anatomy, is essential to its effective use. CT can demonstrate the extent of perirectal and pararectal abnormalities detected on barium enema. While routine preoperative staging of rectal cancer is not justified, CT can be used to solve specific problems. Perhaps the most important role of rectal CT is in evaluating postoperative rectosigmoid cancer patients in an attempt to detect early asymptomatic recurrences and, thereby, prolong patient survival.

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An effective scientific presentation requires skill, experience, and effort. In planning the presentation, a skilled speaker first forms clear conclusions through analysis of the data, then tailors the details of the proof of these conclusions to the interests and background of the audience. The facts and conclusions are presented in a practiced, specific, clear, and logical manner. It is not the topic or the data alone, but the sympathetic and strategic communication of the material to a particular audience that makes a meaningful presentation.

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To evaluate the utility of computed tomographic (CT) staging in patients with esophageal cancer, the length of patient survival was compared with pretherapy CT findings in 89 patients. Regardless of therapy, patients with evidence of mediastinal invasion, liver metastases, or abdominal adenopathy had a statistically shortened survival (P less than .05). Specific CT criteria that predicted a shortened survival included evidence of tracheal, aortic, or pericardial invasion. Patients with evidence of both mediastinal invasion and abdominal metastases had a mean survival of 180.4 days; those with no evidence, 479.6 days. The presence of enlarged upper abdominal lymph nodes indicated the worst prognosis (mean survival, 90 days). The patients with squamous cell tumors were classified by the CT staging system, and survival data were compared according to surgical procedure. Patients who underwent attempted curative surgery did not have a statistically significant difference in survival by analysis of survival curves but demonstrated a longer mean survival than those who underwent palliative or no surgery.

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This study reports a 4 year experience using CT for preoperative staging and for evaluation of patients with rectal and sigmoid carcinoma after surgery. All patients were evaluated on a GE 8800 scanner using 1 cm contiguous slices. Only 15 of the 25 preoperative patients were staged correctly. The other 10 patients were understaged by CT. The accuracy of detecting local invasion was 70%, but only seven (35%) of 20 patients had accurate assessment of lymph nodes. The overall accuracy of CT staging in the 46 postoperative patients was 87%, with a sensitivity of 91% and a specificity of 72%. Most recurrences were found in the pelvis; 16 patients had liver metastases, and metastatic disease obstructing the ureters was detected in eight patients. On the basis of these results, it was concluded that CT should not be used routinely to preoperatively stage patients with rectosigmoid carcinoma. However, all patients who have undergone resection for rectal or sigmoid carcinoma should have aggressive CT evaluation including a baseline study at 2-4 months and then follow-up studies at every 6 months for at least 2 years. All new or enlarging masses should have CT-guided biopsies. This approach may prolong survival by detecting early asymptomatic recurrences.

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Over a 5-year period, 25 patients who had undergone chest computed tomography (CT) died and were autopsied. Their lungs were fixed in the inflated state and were assessed for the presence and severity of centrilobular emphysema (CLE). Three radiologists independently evaluated the CT scans for nonperipheral low-attenuation areas, peripheral low-attenuation areas, pulmonary vascular pruning, pulmonary vascular distortion, and pulmonary density gradient. The CT criterion that best correlated with the presence and severity of CLE was the nonperipheral low-attenuation area. With this CT criterion, lung destruction was correctly identified in 13 of 15 cases. The absence of this criterion resulted in correct identification of eight of ten normal lungs. These preliminary data suggest that CLE can be reliably identified and quantified with current CT scanners.

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Twenty-eight patients with proven bile duct stones were evaluated during either operative or T-tube cholangiography. Two radiographs were obtained for each patient without changing patient position between films. The first was performed with low peak kilovoltage (75-80 kVp) and 15% iodinated contrast medium and the second with high kVp (110) and 38% iodinated contrast. Seven radiologists evaluated the radiographs individually and in matched pairs for ductal filling, ductal penetration, motion unsharpness, overall quality, and stone detectability. The high-kVp radiographs were rated significantly better overall than the low-kVp studies (p less than 0.001) for all five criteria. In the second evaluation, which compared the pairs from the same patients, the 28 high-kVp radiographs were considered superior to the 28 low-kVp studies by the radiologists in almost two-thirds of the comparisons (ductal filling, 68%; penetration, 59%; less motion unsharpness, 65%; overall quality, 77%; stone detection, 62%). On the basis of the results of this study, high-kVp technique with full-strength contrast medium for operative and T-tube cholangiography is recommended.

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CT can accurately distinguish between ascites and pleural fluid if the four signs described here are all considered in each case. Used individually these signs may be indeterminate or misleading.

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A retrospective review of plain abdominal radiographs in 46 patients with gross cecal distension (greater than 10 cm) was performed. In 25 (54%) of 46 patients, the cecum was dilated out of proportion to the rest of the colon and was rotated anteromedially. The term cecal ileus is used to describe this situation. Five (20%) of 25 patients with cecal ileus developed perforation. Four of these patients died as a result of the perforation. The risk of perforation was related more to duration of cecal distension than to absolute cecal size. Aggressive decompressive measures, including consideration of cecostomy, appear warranted in patients with gross cecal distension, especially when it is dilated out of proportion to the rest of the colon and has persisted for several days.

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Calcification has long been a determinant in the radiologic distinction of a benign pulmonary mass. However, rare examples of calcification without ossification in pulmonary adenocarcinoma and ossification in the bronchial carcinoid have led some investigators to warn against this approach. A case of pulmonary adenocarcinoma with stromal ossification is reported herein. The literature is reviewed for neoplasms that exhibit pulmonary ossification either by primary or metastatic lesions. To our knowledge, this case represents the first report of benign osseous stromal metaplasia in the primary lesion of a pulmonary adenocarcinoma.

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Often the CT appearance of adrenal hyperplasia is indistinguishable from the normal appearing gland. We report a case of a 53-year-old man with focal adrenal hyperplasia demonstrated by CT. The CT examination is indistinguishable from bilateral adrenal adenomas.

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