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To retrospectively measure the adrenal gland attenuation and the percentage loss of adrenal gland enhancement at delayed contrast medium-enhanced computed tomography (CT) in patients with adrenocortical carcinomas and pheochromocytomas and to compare these data with those in patients with adenomas and metastases.The study protocol was approved by the ethics committee, which waived informed consent. Eleven patients with proved adrenocortical carcinoma, 17 with proved pheochromocytoma, 23 with adrenal adenoma, and 16 with metastasis to the adrenal gland underwent helical CT. Nonenhanced CT was followed by contrast-enhanced CT 1 minute and 10 minutes later. Attenuation and enhancement loss values were calculated.The mean attenuation of adenomas (8 HU +/- 18 [standard deviation]) was significantly lower than those of adrenocortical carcinomas (39 HU +/- 14), pheochromocytomas (44 HU +/- 11), and metastases (34 HU +/- 11) on nonenhanced CT scans (P.001). Although the mean attenuation values for nonadenomas (ie, adrenocortical carcinomas, pheochromocytomas, and metastases) were significantly higher than the value for adenomas on the 1-minute contrast-enhanced CT scans (P.001), there was more overlap in attenuation between adenomas and nonadenomas on contrast-enhanced scans than on nonenhanced scans. On the 10-minute delayed contrast-enhanced scans, the mean attenuation of adenomas (32 HU +/- 17) was significantly lower than the mean attenuations of carcinomas (72 HU +/- 15), pheochromocytomas (83 HU +/- 14), and metastases (66 HU +/- 13) (P.001). At optimal threshold values of 50% for absolute percentage of enhancement loss and 40% for relative percentage of enhancement loss at 10 minutes, both the sensitivity and the specificity for the diagnosis of adenoma were 100% when adenomas were compared with carcinomas, pheochromocytomas, and metastases.The enhancement loss in adrenocortical carcinomas and pheochromocytomas is similar to that in adrenal metastases but significantly less than that in adrenal adenomas. The percentage change in contrast material washout is a useful adjunct to absolute CT attenuation values in differentiating adrenal adenomas from adrenocortical carcinomas and pheochromocytomas.

To evaluate multi-detector row computed tomographic (CT) urography for detection of urinary tract abnormalities.Sixty-five patients referred from the urology service, in whom urinary tract abnormalities were strongly suspected, underwent multi-detector row CT urography. The technique included unenhanced, nephrographic, compression, and excretory-phase images through the abdomen and pelvis. Transverse images and three-dimensional reformations were reviewed by one of two radiologists. Findings were retrospectively compared with results of urinalysis, cystoscopy and/or ureteroscopy, and/or surgery.Multi-detector row CT urography depicted many clinically diagnosed urinary tract abnormalities, including 15 of 16 uroepithelial malignancies, five congenital anomalies, five urinary tract calculi, and 18 calyceal and/or papillary, 30 renal pelvic and/or ureteral, and 25 bladder abnormalities. All abnormalities were detected on transverse images. These abnormalities included diffuse urothelial wall thickening in four patients (three of whom had transitional cell carcinoma), a renal abscess, a colovesical fistula, and incidentally detected extrarenal disease (a liver mass, hepatic metastases, lymph node metastases, an aortic dissection, and a pheochromocytoma; each of these findings was seen in one patient).Multi-detector row CT urography is a useful method for detecting urinary tract abnormalities.

To assess the relationship between the quantity of lipid in resected adrenal adenomas and the unenhanced computed tomographic (CT) attenuation number and the relative change in signal intensity on chemical shift magnetic resonance (MR) images.The percentage of lipid-rich cortical cells in histologic sections from 20 resected adrenal adenomas was assessed. The results were correlated with the corresponding unenhanced CT attenuation number or the relative change in signal intensity on chemical shift MR images, or both.There was an inverse linear relationship between the percentage of lipid-rich cortical cells in the adrenal adenomas and the unenhanced CT attenuation number (R2 = .68, P = .0005). There was a similar inverse linear relationship to the relative change in MR signal intensity on chemical shift images by using both quantitative (R2 = .83, P = .004) and qualitative (R2 = .70, P = .019) assessment.The presence and amount of histologic lipid in many adrenal adenomas accounts for their low attenuation on unenhanced CT scans and their loss in relative signal intensity on chemical shift MR images.

The effect of Gastrografin and glucagon on pancreatic CT scanning was studied in a blind clinical trial. Twenty-five patients had a pancreatic CT scan performed on an 18-second scanner and a repeat pancreatic CT scan following administration of Gastrografin and glucagon. The results were statistically significant: decreased streak artifacts; improved pancreatic head, body and tail delineation; and improved overall pancreatic visualization. Gastrografin-glucagon administration is recommended prior to pancreatic CT scanning if the scanning cycle is 18 seconds or longer.

Patients who have undergone surgery on the thoracic aorta and placement of a synthetic tubular graft need close, long-term radiological follow-up, as they are at risk of not only complications and progression of the underlying disease (atherosclerosis, dissection, or cystic medial necrosis) but also complications of the procedure, notably suture dehiscence leading to formation of an aneurysm around the graft. In a series of 14 asymptomatic postoperative patients studied by computed tomography (CT), the authors detected leakage of contrast material around the graft in 6 patients, 2 of whom required re-operation to correct suture dehiscence. CT is a noninvasive and sensitive method of postoperative evaluation of patients who have undergone an aortic graft.

Hepatic CT scans in 61 consecutive patients with proved liver metastasis performed both before and after administration of contrast medium were subjected to blind analysis by two observers. In 10 patients (16%) hepatic lesions were better defined before CE and focal hepatic lesions were diagnostically visible only before CE in 8 patients (13%). Lesions were better defined following CE in 16 patients (26%) but in only 2 cases (3%) were lesions diagnostically visible only after CE. The majority of lesions [35 (58%)] were equally well visualized before and after CE.

Twenty consecutive patients underwent computed tomography (CT) prior to total laryngectomy in order to assess the accuracy of CT scanning in the evaluation of carcinoma of the larynx and hypopharynx. CT scans were prospectively interpreted and the extent of tumor was recorded graphically at five major levels of the larynx. The extent of tumor was similarly evaluated on whole-mount histologic sections of the laryngeal specimens prepared in the horizontal plane similar to the CT scans. The results were compared to assess the ability of CT to identify tumor extent accurately. Despite good correlation of gross tumor extent between histologic specimens and CT scanning, specific pitfalls in CT diagnosis were identified. Overestimation of tumor extent was caused by edematous changes in six patients and tumor-associated inflammatory changes in three patients. In seven patients, mass effect from adjacent bulky tumor significantly distorted normal structures, mimicking tumor involvement. Small foci of mucosal tumor in three patients and microscopic cartilage involvement in two patients were not identified on CT scanning, causing underestimation of tumor extent.

Sixty-one consecutive patients suspected of having pancreatic neoplasms had endoscopic retrograde cholangiopancreatography (ERCP) and computed tomography (CT). The ERCP results were 62% accurate, 8% false negative, and 3% failure. The overall accuracy in cases of successful pancreatic duct cannulation was 88%. The results of CT were 76% correct, 5% false positive, 13% false negative, and 6% indeterminate. Excluding ERCP failure, the CT-ERCP diagnosis was identical in 67%. When findings were identical, the accuracy rate was 93%, high than that of either study alone. The ERCP-CT examinations were often complementary and generally led to a more accurate and specific diagnosis.

Forty-two patients with T2 bronchogenic carcinoma were evaluated with plain radiography, conventional 55 degrees oblique hilar and anteroposterior mediastinal tomography, and computed tomography (CT) to compare their accuracy in assessing mediastinal and hilar nodal metastases. Definitive staging was achieved by thoracotomy and histopathological evaluation of resected specimens. All modalities demonstrated about the same accuracy; however, in the 25 patients with hilar and/or mediastinal lymphadenopathy, CT of the mediastinum was more sensitive but not more specific than the other two and conventional tomography was no more accurate than CT for hilar evaluation. Overall, no technique was accurate enough for routine staging; their value may lie in directing biopsy or in treatment planning in patients with inoperable disease.

Unilateral reduction in renal perfusion pressure has been produced in dogs using selective renal artery catheterization with a balloon catheter. The effects of reduced perfusion pressure can now be studied by means of renal arteriography and excretory urography in the absence of systemic hypovolemia. The contralateral kidney serves as a convenient “normotensive” control for radiologic observation of physiologic alterations in the hypotensive kidney.

A retrospective study was made of 29 consecutive patients who were evaluated for suspected abdominal abscess by at least two of three imaging modalities: gallium-67 scanning, ultrasonography, and computed tomography. No statistically significant difference in accuracy of the findings could be demonstrated. Consideration of the advantages and disadvantages of each imaging modality will often indicate which to use in an individual case. Findings from the three imaging techniques sometimes provided complementary rather than identical information.

Eight patients were studied arteriographically after hepatic artery ligation (done to control bleeding in 6). Sources of arterial flow to the liver after ligation were (a) replaced or accessory hepatic artery; (b) interlobar collaterals in the liver; (c) right inferior phrenic artery; (d) through the gastroduodenal artery from arterial branches in the pancreas, duodenum, and omentum; (e) fine collateral branches of the gastroduodenal artery as they pass into the porta hepatis; and (f) recanalization of the ligated hepatic artery. Collateral vessels, seen as early as four hours after ligation, increased in size and number during the following six months.

Vasoseminal vesiculography showed medial displacement and stretching of the ampulla of the vas deferens in 3 patients with cysts of the seminal vesicle. In 2 a nonopacified mass separated the ampulla from the ipsilateral seminal vesicle. All 3 patients were managed without surgical intervention. If such a vesiculographic pattern is seen in a patient with a paraprostatic mass, the contents of the mass should be aspirated and contrast material injected to document its cystic nature.

The use of computed tomography (CT) in diagnosing disorders affecting the hollow viscera of the alimentary tract has received little attention. The authors reviewed CT scans of 43 patients on which lesions affecting the gastrointestinal tract were demonstrated. All cases were correlated with barium-enema examinations, surgical reports, or autopsy findings. CT can provide valuable information on the extraluminal extent of masses arising in the bowel, mesenteric masses, and can define and characterize extrinsic lesions. The authors's results suggest that CT is a useful adjunct in evaluating intramural or mesenteric lesions of the gastrointestinal tract.

Arteriovenous fistulas between the systemic and portal circulations developed in 3 patients following partial gastrectomy. The diagnosis was not made until several years later. An abdominal bruit was present in all 3. Arteriography demonstrated the fistula and outlined the specific vascular anatomy. Complete excision of such a fistula is important, as it frequently leads to portal hypertension.

Seven examples of focal nodular hyperplasia of the liver have been demonstrated angiographically in 3 young women and 19-year-old girl. Six of these lesions were small and highly vascular, and appeared remarkably similar. One large solitary lesion was supplied by enlarged hepatic artery branches, contained a mass of abnormal, tortuous, irregular vessels and caused a dense, well-defined tumor stain. The angiographic differential diagnosis of these highly vascular, benign lesions is discussed and the radionuclide studies in these patients described.

Four instances of prolonged nephrographic phase in patients with arterial hypotension are reported. Prolonged bilateral nephrograms during excretory urography should alert the radiologist to the possibility of arterial hypotension. Although the mechanism of the hypotensive nephrogram is not fully understood, continued glomerular filtration rather than tubular secretion is postulated as the most likely explanation.

A focal defect was seen on a gamma camera image of the liver in 2 patients, a 52-year-old woman with abdominal pain and a 46-year-old woman with pancytopenia. Liver function was normal, and no tumor stain was seen. Angiography revealed that the "defect" was in reality the bifurcation of the portal vein. These findings re-emphasize the importance of visceral angiography as a complement to radionuclide imaging in the study of liver disease.

Investigators have been able to distinguish benign pulmonary nodules from malignant ones in about two-thirds of the cases studied by detecting high computed tomography (CT) numbers (attributed to microscopic calcifications) within many benign nodules. This paper reports a similar analysis on a series of 22 benign and 14 malignant pulmonary nodules. Although about one-third of the benign nodules gave high CT numbers, all but one of the nodules diagnosed as benign by CT could also be diagnosed by detection of calcification on plain radiographs or conventional tomograms.