Gender risk for anaphylactoid reaction to radiographic contrast media.

BACKGROUND: Female predominance has been reported previously in series of anaphylaxis cases; however, no definite precedent has been established for greater risk of anaphylactoid reaction caused by contrast media infusion on the basis of gender. OBJECTIVE: This study was designed to determine whether greater risk for anaphylactoid reaction caused by intravenous contrast media infusion exists in association with female gender. METHODS: Rates of anaphylactoid and severe anaphylactoid reaction, according to gender, were determined in a sample of 5264 consecutive patients receiving conventional radiocontrast media during performance of computed tomography. RESULTS: Of 80 adverse reactions caused by contrast media infusion, 73 (1.39%) were classified as anaphylactoid in nature. Among 5191 patients who received intravenous contrast media without experiencing an anaphylactoid reaction, there were 2642 male patients (51%) and 2549 female patients (49%); reactors included 22 male patients and 51 female patients (odds ratio = 2.40, 95% confidence interval = 1.42-4.10, p < 0.0005). Female patients also comprised 21 of 22 cases of severe anaphylactoid reaction (odds ratio = 21.77, 95% confidence interval = 3.13-435.12, p < 0.0005). CONCLUSION: Greater risk for anaphylactoid and severe anaphylactoid reaction exists in association with female gender. Further studies are needed to identify mechanisms that can explain this risk. The importance of these findings for cost-effective use of lower osmolality contrast media need to be determined.

Abdominal aortic aneurysms: CT evaluation of renal artery involvement.

PURPOSE: To determine whether computed tomography (CT) assessment of the proximal extent of ruptured aneurysms can help the surgeon determine whether to initially clamp the pararenal aneurysm neck or the supraceliac aorta. MATERIALS AND METHODS: CT scans and medical records were reviewed and compared for 30 patients with ruptured abdominal aortic aneurysms (AAAs) who underwent immediate surgical repair. RESULTS: For 49 of 50 vessels in 25 patients, the authors correctly predicted at CT that AAAs originated caudal to the main renal artery origins. They also predicted that nine main renal arteries in five patients originated directly from the AAAs, but this was correct in only five arteries. Suprarenal clamping was required in all five patients. Infrarenal clamps were used before reconstruction in all 12 of the patients whose AAAs appeared to originate at least 30 mm below the main renal arteries. CONCLUSION: CT can help predict whether an initial aortic clamp can be placed caudal to the main renal artery orifices. Its use can be predicted with 100% certainty only when an aneurysm appears to originate at least 3 cm caudal to the origin of the main renal artery.

Abdominal aortic aneurysm morphology: CT features in patients with ruptured and nonruptured aneurysms.

OBJECTIVE: We evaluated a variety of internal architectural features in ruptured and nonruptured abdominal aortic aneurysms to determine whether any features are associated more frequently with ruptured abdominal aortic aneurysms. These features may be useful in identifying subtle ruptures when no obvious retroperitoneal hematoma is present and may be helpful in predicting unstable aneurysms at risk for rupture. MATERIALS AND METHODS: The CT scans of 52 patients with ruptured abdominal aortic aneurysms were reviewed and compared with those of 56 patients with asymptomatic nonruptured aneurysms exceeding 4.5 cm in diameter. All aneurysms were evaluated for size, rim calcification, thrombus amount, thrombus calcification, and lumen irregularity. In addition, four different thrombus patterns were identified and evaluated, including homogeneous, diffusely heterogeneous, periluminal halo, and crescent patterns. Statistical comparisons were adjusted for differences in size between the two groups. RESULTS: Age, gender, and aneurysm length were not statistically different between the two groups. A larger diameter was found in the ruptured aneurysm group: 7.4 (anteroposterior) x 7.9 (transverse) cm versus 5.9 x 6.1 cm (p = .00001). More thrombus surrounded the nonruptured aneurysms (p = .014). Thrombus calcification was seen in 25% (14/56) of the control group and in 13% (7/52) of the rupture group (p = .01). Two thrombus patterns, homogeneous and periluminal halo, were encountered with similar frequencies in both groups. The diffusely heterogeneous pattern was seen more in the control group. A crescent of increased attenuation was encountered only in patients with ruptured aneurysms, at an incidence of 21% (11/52) (p = .0005). Thick and thin wall calcifications were seen in both groups, but a focal discontinuity in circumferential calcification was seen only in association with ruptured aneurysms, at an incidence of 8% (4/52) (p = .008). There was no significant difference in the number of patients whose patent lumen was irregular. CONCLUSION: In our series, detection of a high-attenuation crescent or focal gap of otherwise circumferential wall calcification is associated with aneurysm rupture. The homogeneous, diffusely heterogeneous, and periluminal halo patterns are not specifically associated with aortic rupture. There were no significant differences in the amount of wall calcification or frequency of lumenal irregularity between patients with ruptured and those with nonruptured aneurysms.

Elevated risk of anaphylactoid reaction from radiographic contrast media is associated with both beta-blocker exposure and cardiovascular disorders.

BACKGROUND: A case-control study, with both retrospective and concurrent subject selection, was performed (1) to determine whether greater risk for anaphylactoid reaction from contrast media associated with beta-blocker exposure reflects presence, or is independent of underlying cardiovascular disorder; and (2) to characterize further the risk of anaphylactoid reaction from contrast media in patients with cardiovascular disorders and patients with asthma. METHODS: Adverse reactions from intravenous contrast media were recorded in accordance with quality assurance guidelines. Anaphylactoid reactions were classified as mild to moderate (urticaria/angioedema), severe (stridor, bronchospasm, or hypotension), or major and life-threatening (hypotension with or without the need for subsequent hospitalization). Medical records from reactors were compared with those from matched (gender, age, date, and type of contrast study) controls who received conventional contrast media without adverse reaction. RESULTS: Of 34,371 intravenous contrast media procedures performed, 122 anaphylactoid reactions were recorded. The risk of anaphylactoid reaction was significantly associated with asthma (odds ratio [OR], 8.74; 95% confidence interval [CI], 2.36 to 32.35; P = .0012). The risk of bronchospasm was associated with beta-blocker exposure (OR, 3.73; 95% CI, 1.18 to 11.75; P = .025) and with asthma (OR, 16.39; 95% CI, 4.30 to 62.46; P = .0001). The risk of major and life-threatening reaction was associated with the presence of cardiovascular disorder (OR, 7.71; 95% CI, 1.04 to 57.23; P = .046). Among patients with severe reactions, the risk of hospitalization was elevated by the presence of cardiovascular disorder (P = .001), exposure to beta-blockers (OR, 7.67; 95% CI, 1.79 to 32.85; P = .029), or asthma (OR, 20.7; 95% CI, 1.21 to 355.55; P = .065). Although beta-blocker exposure and the presence of cardiovascular disorder were highly associated (chi 2 = 49, P < .001), a greater risk of bronchospasm with severe reaction was observed in nonasthmatic patients with cardiovascular disorders receiving beta-blockers (OR, 15.75; P = .023). Among reactors with asthma, receiving beta-blockers, or with a cardiovascular disorder, 60.8% (31/51) experienced severe anaphylactoid reactions, compared with 35.2% (25/71) of patients without these risk factors (OR, 3.62; P = .005). CONCLUSIONS: beta-Blocker exposure and cardiovascular disorder are both statistically significant risk factors for severe anaphylactoid reaction from contrast media. Thus, patients receiving beta-adrenergic blockers and patients with asthma, on the basis of greater risk for bronchospasm, and patients with cardiovascular disorders, on the basis of elevated risk of major and life-threatening reaction, are appropriate target populations for risk reduction measures before receiving intravenous infusion of contrast media.

Upper abdominal lymph nodes: criteria for normal size determined with CT.

Reports of the upper limits of normal for lymph node size at abdominal computed tomography have varied from 6 to 20 mm. Establishment of an upper limit for node size by specific location, analogous to that which has been reported for mediastinal lymph nodes, was sought. Short-axis diameters of the lymph nodes were measured in 130 patients who were not likely to have enlarged abdominal lymph nodes. Seven locations were defined, and the largest nodal measurement for each was recorded. Histographic analysis and nonparametric statistical methods were used to determine threshold values for the maximum node size in each region. The upper limits of normal by location were as follows: retrocrural space, 6 mm; paracardiac, 8 mm; gastrohepatic ligament, 8 mm; upper paraaortic region, 9 mm; portacaval space, 10 mm; porta hepatis, 7 mm; and lower paraaortic region, 11 mm. Lower paraaortic lymph nodes larger than 11 mm by short-axis measurement are abnormal. In other locations, nodes smaller than 1 cm may be abnormal if the determined thresholds are exceeded.

Increased risk for anaphylactoid reaction from contrast media in patients on beta-adrenergic blockers or with asthma.

OBJECTIVE: To determine whether greater risk for anaphylactoid reaction from intravenous urographic contrast media exists in patients receiving beta-adrenergic blockers or in asthmatic patients. DESIGN: Case-control study. SETTING: Tertiary care, referral-based medical center. PATIENTS: Of 28,978 intravenous urographic contrast media procedures done from July 1987 to June 1988, 49 patients experienced moderate to severe anaphylactoid reaction. Medical records from these 49 reactors were compared with those from a control group matched for gender, age, and date and type of contrast study who received intravenous urographic contrast media without adverse reaction. MAIN RESULTS: Patients exposed to beta-adrenergic blockers or with asthma comprised 39% (19 of 49) of reactors, compared to 16% (13 of 83) of matched controls (odds ratio, 3.43; 95% CI, 1.45 to 8.15; P = 0.005). Exposure to beta-blockers was 27% among reactors and 12% in matched controls (odds ratio, 2.67; CI, 1.01 to 7.05; P = 0.036). Asthma was found in 12% of reactors and 4% of controls; after correction for beta-blocker use, asthma was also associated with increased risk for anaphylactoid reaction (odds ratio, 4.54; CI, 1.03 to 20.05; P = 0.046). Compared with nonasthmatic patients not taking beta-blockers, asthmatic patients were at greater risk for anaphylactoid reaction with bronchospasm (P = 0.02). Five of 13 reactors receiving beta-blockers became hypotensive, and three needed hospitalization. Compared with nonasthmatic patients not taking beta-blockers, patients exposed to beta-blocking drugs were almost nine times (odds ratio, 8.7; CI, 0.81 to 93.5; P = 0.075) more likely to be hospitalized after an anaphylactoid reaction. CONCLUSION: Increased risk for moderate to severe anaphylactoid reaction from intravenous urographic contrast media exists in patients receiving beta-adrenergic blockers or with asthma. These patients are appropriate target populations for efforts to reduce risk before intravenous urographic contrast media are administered.

Seminal vesicle cysts: association with adult polycystic kidney disease.

Adult polycystic kidney disease (APKD) is associated with cyst formation in the kidney, liver, pancreas, esophagus, ovary, uterus, and brain. Four patients with APKD (aged 45-65 years) with computed tomographic evidence of seminal vesicle cysts are described. All seminal vesicles contained cystic masses with attenuation values of 0-30 HU. Seminal vesicle thickness was 3-4 cm (normal, 1.5 cm). High-attenuation walls separated the cysts, which were 3-35 mm in diameter. All patients had typical renal stigmata of APKD. None had cysts elsewhere, except one patient with hepatic cysts. Postmortem examination in one patient confirmed the seminal vesicle cysts as well as APKD. It is likely that a basement membrane defect allows cyst formation in multiple organs, presumably including the seminal vesicles. Because of the association of seminal vesicle cysts with ipsilateral urogenital anomalies, and because only 60% of patients with APKD have a relevant familial history, the kidneys of patients with cross-sectional imaging evidence of seminal vesicle cysts should also be studied.

Biliary cystadenoma and cystadenocarcinoma: CT and sonographic findings.

Biliary cystadenomas and cystadenocarcinomas are rare cystic neoplasms, usually intrahepatic in location, that are characterized pathologically by a multilocular appearance. We report the CT and sonographic findings in eight cases of biliary cystadenoma and three cases of biliary cystadenocarcinoma and correlate them with the surgical and pathologic findings. CT showed internal septa in eight of the 10 multiloculated lesions, whereas sonography showed septa in all five cases in which it was used. CT in two of the three cystadenocarcinomas showed thick and coarse mural and septal calcifications as well as large solid soft-tissue masses in one. CT showed mural soft-tissue nodules in the single case of a unilocular cystadenocarcinoma. Sonography and CT usually show the multilocular nature of biliary cystadenomas and cystadenocarcinomas. The presence of mural or septal nodules, discrete soft-tissue masses, and possibly thick and coarse calcifications increase the likelihood of a cystadenocarcinoma.

Case report: CT of a duodenal paraganglioma.

Paraganglioma is a neoplasm of neuroectodermal origin that occurs rarely in the bowel. This case report illustrates the previously undescribed CT appearance of a duodenal paraganglioma. An intensely enhancing mass in the region of the pancreatic head was found. The intense enhancement ruled out adenocarcinoma and focal pancreatitis. An islet cell tumor of the pancreas was the major differential diagnostic consideration.

Computed tomography of vena caval anomalies with embryologic correlation.

Vena caval and left renal vein anomalies are not uncommon and are easily identified by CT, usually in an incidental fashion. A simple classification of these anomalies is presented (Table I). These anomalies become significant only when they are mistaken for pathologic masses or when one is planning surgical or radiologic vascular procedures. Detailed knowledge of these anomalies, in conjunction with the use of dynamic bolus CT, will permit easy diagnosis in nearly all cases.

CT of renal cell carcinoma in patients on chronic hemodialysis.

The occurrence rate of renal cell carcinoma is significantly higher in the native kidneys of patients undergoing chronic hemodialysis than in kidneys of normal subjects. These carcinomas may be difficult to detect because these kidneys tend to be small and distorted owing to acquired cystic disease. Four cases of renal cell carcinoma detected by CT are presented (three in patients undergoing chronic hemodialysis, and one in a patient with a functioning transplant who had history of dialysis). All kidneys had extensive acquired cystic disease. In two cases, contrast-enhanced scans showed a solid lesion of lower density than the kidney. In another case, in which IV contrast material could not be given, the mass was of higher density than the kidney and retroperitoneal lymphadenopathy was present. In the fourth case, no distinct solid mass could be identified. The only sign of malignancy in this case was extensive lymphadenopathy. Whenever CT examination of the abdomen is performed in a patient undergoing chronic hemodialysis, the kidneys must be evaluated carefully because of the increased frequency of renal cell carcinoma. In a few cases, a distinct solid lesion may not be apparent or may be subtle owing to distortion of renal anatomy by acquired cystic disease.

Small-cell bronchogenic carcinoma: CT evaluation.

CT examinations in 37 patients with proved small-cell bronchogenic carcinoma studied before treatment were reviewed. The distribution of lymphadenopathy in the mediastinal compartments designated by the American Thoracic Society was assessed. The frequency of lymph node enlargement was right hilum (43%), left hilum (49%), one or both hila (84%), right upper paratracheal (32%), right lower paratracheal (54%), right tracheobronchial (65%), left upper paratracheal (14%), left lower paratracheal (38%), left peribronchial (35%), paraesophageal (14%), anterior mediastinum (24%), and subcarinal (65%). We also assessed the frequency of additional findings including pleural effusion (38%), pericardial thickening (38%), displacement or narrowing of either the tracheobronchial tree (68%) or major vessels (68%), and hepatic masses (24%). Mediastinal involvement was present in 92% of cases, as compared with 13% reported in a large series based on conventional radiography. These data show the spectrum of intrathoracic CT findings in proved, untreated cases of small-cell bronchogenic carcinoma.

Ischemic or infarcted bowel: CT findings.

Computed tomography (CT) has been used in the evaluation of patients with suspected bowel ischemia or infarction. To assess its efficacy in this setting, the CT scans and medical records of 23 patients with proved bowel ischemia or infarction were retrospectively reviewed. Surgery or autopsy revealed that the colon was involved in 17 patients, the small bowel in 13, and the stomach in one (some patients had multiple sites of involvement). The prospective CT interpretation enabled a specific diagnosis of bowel ischemia or infarction in only six of 23 patients (26%). However, in 13 patients (56%), the CT scans were considered useful in patient treatment. A retrospective review of CT scans indicated that bowel dilatation was present in 13 of 23 patients (56%); however, it was not always restricted to the ischemic area. Six of 23 patients (26%) had bowel wall thickening greater than 3 mm, but two had thickening in areas that were not ischemic at surgery. Pneumatosis intestinalis and portal venous gas were seen in only five patients (22%) and three patients (13%), respectively. Superior mesenteric artery thrombosis and free intraperitoneal gas were each found in only one patient (4%).

Abdominal lymphadenopathy in benign diseases: CT detection.

A review of 2,100 consecutive computed tomographic (CT) examinations yielded 160 cases of abdominal lymphadenopathy, of which nine (6%) were secondary to benign diseases. Contrary to previous reports, size, location, contour, density, relationship to the aorta, and presence of mass effect were not helpful in distinguishing benign from malignant lymphadenopathy. In some cases, ancillary CT findings, conventional radiographs, and clinical setting may suggest a specific benign entity. Benign processes should be considered in the differential diagnosis of abdominal lymphadenopathy in the appropriate clinical setting, particularly if the patient does not have a known carcinoma.

Porta hepatis: duplex Doppler US with angiographic correlation.

Duplex Doppler ultrasonography (US) and panhepatic angiography were performed and interpreted independently in 20 patients with suspected portal hypertension to assess the accuracy of duplex US in the porta hepatis. Hepatic arterial resistive indexes were correlated with corrected sinusoidal pressures. The results of duplex US agreed with those of angiography in 16 patients with a normal portal vein (including three with hepatofugal flow) and two with total thrombosis. One angiographically normal portal vein appeared thrombosed on an initial sonogram, but a second scan was normal. One case of partial thrombosis was not diagnosed with duplex US. Sensitivity and specificity for main portal vein disorders were 83% and 93%, respectively. Two patients had portal vein branch occlusions that were found by angiography but not by US. Portal vein echogenicity was neither sensitive nor specific for thrombosis. The resistive index of the hepatic artery was specific for portal hypertension when above .78, but it was not sensitive. Duplex US is accurate in prospectively assessing the direction of flow and the presence of total thrombosis in the portal vein, but partial thrombosis may not be detected on sonograms.

Hypervascular hepatic metastases: CT evaluation.

Recent reports have indicated that non-contrast material-enhanced scans are of less value than urographic contrast material-enhanced studies in the computed tomographic (CT) evaluation of hepatic metastases. The authors retrospectively reviewed the CT scans of 28 patients with hypervascular liver metastases to determine whether these metastases were more likely to become isodense with the liver after contrast material enhancement, thus necessitating the performance of non-contrast-enhanced scanning. Non-contrast-enhanced and contrast-enhanced incremental dynamic scanning was performed in patients with proved liver metastases from carcinoid tumors (13 patients), islet cell neoplasms (ten patients), pheochromocytomas (four patients), or renal cell carcinoma (one patient). Eleven of the 28 patients (39%) had metastases with non-contrast liver-to-lesion attenuation differences greater than 15 HU. These metastases subsequently became isodense or nearly isodense on contrast-enhanced scans. The authors conclude that non-contrast-enhanced CT scanning should be performed in patients with suspected liver metastases from tumors that are usually hypervascular.

CT appearance of hemangiopericytoma.

Hemangiopericytoma is an uncommon tumor that may occur anywhere in the body but is most often found in the retroperitoneum, extremities, and nasopharynx. The CT evaluation of five malignant hemangiopericytomas (two retroperitoneal, two nasopharyngeal, one thigh) revealed speckled calcifications in all cases. The lesions in the retroperitoneum and thigh were large and lobular, with areas of cystic-degeneration or hemorrhage. Computed tomography of a rare, benign osseous hemangiopericytoma demonstrated characteristics of a slow-growing bone tumor with a cortical break in the proximal femur. The homogeneously enhancing, noncalcified mass found in the posterior fossa appeared similar to the typical benign hemangiopericytoma reported in this location by other authors.

Focal hepatic masses and fatty infiltration detected by enhanced dynamic CT.

A prospective evaluation of 185 consecutive patients with abdominal pain or suspected hepatic malignancy was performed to compare the diagnostic accuracy of contrast material-enhanced incremental dynamic computed tomography (IDCT) scans with plain CT scans for detection of hepatic masses and fatty infiltration of the liver. After a series of nondynamic plain CT scans, patients were examined at 7.5 scans/min during intravenous injection of 50 g of iodinated contrast material. Enhanced IDCT study was found to be an accurate, reproducible technique for liver evaluation. Of 155 neoplasms measured in 59 patients, liver-to-lesion differences of less than 10 HU were seen in only two tumors in IDCT scans as compared with 31 in plain CT scans. These differences were not significantly affected by lesion size for neoplasms greater than 6 mm in diameter. A confident diagnosis of fatty infiltration (23 patients) could be made when the spleen-minus-liver difference was 25 HU on enhanced IDCT scans and 10 HU on plain CT scans. In eight patients with liver metastases, there was little variation in the attenuation values of normal-appearing liver between serial examination studies (8 HU average).