Experimentally induced pulmonary arterial occlusion with detachable balloon in pigs: thin-section CT findings

RATIONALE AND OBJECTIVES: The authors evaluated changes of lung attenuation in pigs, with special attention to the mosaic pattern of low attenuation, at thin-section computed tomography (CT) after obstruction of the proximal pulmonary artery with a detachable balloon. MATERIALS AND METHODS: In seven pigs, nine sites of the descending pulmonary artery were obstructed with detachable balloons. This-section CT scans of the lungs were obtained immediately (n = 9) and at 1 week (n = 5), 2 weeks (n = 1), 3 weeks (n = 2), 4 weeks (n = 1), 6 weeks (n = 1), 8 weeks (n = 1), and 12 weeks (n = 1) after pulmonary artery obstruction. RESULTS: No statistically significant difference was found between the measured lung attenuation of the normal lung and that of the lung distal to the obstruction. Of the nine sites of pulmonary artery obstruction, five (56%) showed an irregular area of increased lung attenuation without lobular architecture. The diameter of the pulmonary artery after obstruction, compared with the diameter before obstruction, decreased by a range of 13%-57% (mean, 35%) and by 0-67% (mean, 44%) at levels 1 cm and 2 cm distal to the obstruction, respectively. CONCLUSION: This experimental study reveals that regional low-attenuation areas do not develop for up to 12 weeks after the obstruction of proximal pulmonary artery, despite a marked decrease in the diameter of the pulmonary artery distal to the obstruction.     

Acute pulmonary embolism: ancillary findings at spiral CT

Metoprine elevates brain histamine content by blocking the conversion of histamine to methylhistamine. It suppresses food intake, increases water intake. and induces diuresis in rats. In the present experiment, to study which receptors were involved in these metoprine-induced changes, H1, H2, and H3 receptor blockers were administered to metoprine (10 mg/kg IP)-treated rats. The food and water consumption and urine excretion were measured at 10 and 24 h after the drug administration. It was found that systemic administration of the H3 receptor antagonist, thioperamide (5 mg/kg IP), supplemented the feeding suppressive effect of metoprine. In addition to this, the H1 receptor antagonist mepyramine (20 mg/kg IP) antagonized the suppression of feeding in metoprine-treated rats, whereas the H2 receptor antagonist, ranitidine (100 mg/kg IP), had no effect. Mepyramine also decreased the diuretic response to metoprine, whereas ranitidine or thioperamide were virtually without effect. The present results show that elevation of brain histamine content by inhibiting the catabolism of histamine suppresses food intake, and this effect of metoprine can be abolished by pretreatment with antihistamines. Although the blockade of H1 receptors also attenuates the diuretic response to metoprine, further studies are needed to understand the mechanisms that mediate the effects of metoprine on water balance.     

Cavernous hemangioma of the liver: pathologic correlation with dynamic CT findings

Malignant mixed mesodermal tumors (MMMT) are the most malignant neoplasms known to occur in the uterus. The most important prognostic factors are the extent of tumor at diagnosis, depth of myometrial invasion, and, as regarded by some authors, the sarcomatous component. We report on a retrospective analysis in 83 patients with MMMT. By univariate analysis survival was dependent on stage, depth of myometrial invasion, kind of therapy, age at menopause, and parity. However, the sarcomatous component did not significantly influence survival. Using the multivariate Cox regression analysis stage and parity or depth of myometrial invasion and parity were found to independently predict prognosis. Despite an interval of more than 20 years from the last childbirth to tumor appearance a beneficial influence of parity on the prognosis of MMMT was identified. This is unique in oncology. Especially patients with more than three children formed a subgroup of long-term survivors. It is interesting to note that parity was found by means of a Cox regression analysis to be statistically independent, and no correlation with other classical prognostic factors was detected.     

Case report: malignant haemobilia detected in the gallbladder--retrograde cholangiographic findings

Haemobilia caused by gallbladder cancer is a rare condition and cholangiography rarely detects gallbladder haemorrhage because cancer cells or blood clots obstruct the cystic duct. We describe a patient with haemobilia caused by gallbladder cancer, in whom retrograde cholangiography showed a cast-like filling defect in the common bile duct and, in addition, several string-like defects in the gallbladder. The string-like defects appeared to be streams of clotted blood flowing towards the common bile duct in this case of relatively minor haemorrhage.     

Thrombosis of the deep cerebral veins: CT and MRI findings with pathologic correlation

Deep cerebral vein thrombosis can present with acute, severe neurological symptoms and may be rapidly fatal as in the 20-year-old woman reported here. Although MRI is superior for establishing the diagnosis, CT is usually the first examination performed in the clinical setting. It is therefore important to recognise certain indicators such as extensive bithalamic low density. These and certain other less specific signs are correlated with the MRI and autopsy findings.     

MIBG detection of hepatic neuroblastoma: correlation with CT, US and surgical findings

The combination of ultrasound contrast media (US-CM) and color-coded duplex sonography (CCDS) is a very promising new diagnostic method. The principles of CCDS and US-CM are therefore briefly discussed. Different US-CM are described regarding their application and possible indications. This is followed by a summary of the first clinical experience with this new method.     

Wedge-shaped intrahepatic cholangiocarcinoma: MRI-pathologic correlation

Magnetic resonance (MR) examination of 42 normal wrists was performed for evaluation of anomalous musculature. A total of 23 muscle variations were found. An accessory abductor digiti minimi was found in 10 wrists (24%), an absent palmaris longus was found in seven wrists (16%), a muscular palmaris longus tendon was found in three wrists (7%), a muscular flexor digitorum superficialis was found in two wrists (5%), and an aberrant lumbrical muscle originating from within the carpal tunnel was found in one wrist (2.4%). Such muscle variations can be distinguished by MR from other mass lesions at the wrist and a knowledge of their frequency, appearance, and location can be of help in this regard.     

Nontumorous arterioportal shunt mimicking hypervascular tumor in cirrhotic liver: two-phase spiral CT findings

PURPOSE: To determine the two-phase (hepatic arterial phase [HAP] and portal venous phase [PVP]) spiral computed tomographic (CT) findings of a nontumorous arterioportal shunt in the cirrhotic liver that can mimic a hypervascular tumor. MATERIALS AND METHODS: For 14 months, 803 patients with known or suspected hepatocellular carcinoma were referred for initial or repeated transcatheter arterial chemoembolization (TACE). Twenty-nine hyperattenuating lesions on HAP CT images obtained in 25 patients (23 men, two women; age range, 39-70 years) were regarded as nontumorous arterioportal shunts and were included in this study. The diagnosis of nontumorous arterioportal shunt was established by four radiologists who reviewed the two-phase spiral CT images and hepatic angiograms. RESULTS: The longest dimension of the lesion was 1.0-7.9 cm (mean dimension, 2.9 cm). The morphology at HAP CT was wedge-shaped in 25 (86%), geographic (ie, focal area with irregular outline) in two (7%), and nodular in two (7%) lesions. All lesions were homogeneous in attenuation. Hyperattenuating linear branching structures that represented early opacification of portal veins were demonstrated during the HAP in nine (31%) lesions. PVP CT images showed these lesions as isoattenuating (n = 20 [69%]) or slightly hyperattenuating (n = 9 [31%]). Iodized oil CT images showed faint or no accumulation of iodized oil in all lesions. CONCLUSION: In cirrhotic liver, nontumorous arterioportal shunts can be a cause of pseudolesions that mimic hypervascular tumors at two-phase spiral CT. Lesions that have the typical wedge-shaped and homogeneous appearance with or without internal linear branching structures during the HAP and that are isoattenuating or slightly hyperattenuating during the PVP can suggest this unusual condition.     

Benign pulmonary nodule: morphological features and contrast enhancement evaluated with contiguous thin-section CT

The morphological changes in 54 benign lung nodules, including 8 histologically proven nodules of tuberculoma, 10 of focal organizing pneumonia (FOP), 1 of lung abscess and 35 other benign nodules, were evaluated with contiguous thin-section (3mm) CT. In addition, incremental dynamic studies were carried out in 25 of these nodules. The three-dimensional shapes of the nodules were found to be quite varied and were classified into four types: (A) round mass (n = 18), (B) polygonal mass with concave or straight margins (n = 20), (C) oval or band-like mass extending along the bronchovascular bundle (n = 7), (D) oval mass attached to the pleura with broad contact (n = 9). Forty-two (78%) of the 54 nodules were located along the bronchovascular bundle. The maximum increments in CT values over 20HU were observed after contrast enhancement in 18 (72%) of the 25 benign nodules, among which all tuberculomas showed little or no contrast enhancement. The number of small vessels quantified microscopically in teh center of the nodules were minimal in tuberculomas with little enhancement and plentiful in lesions of FOP and abscess which showed marked enhancement. Our results suggest that the differentiation between benign and malignant pulmonary nodules is not possible simply on the basis of the degree of contrast enhancement. Therefore, morphological features and the anatomical relation to the bronchovascular bundles should also be taken into consideration in the diagnosis of pulmonary nodules.     

Pulmonary sarcoidosis: morphologic associations of airflow obstruction at thin-section CT

PURPOSE: To identify relationships between the obstructive defects of pulmonary sarcoidosis and the computed tomographic (CT) patterns of disease. MATERIAL AND METHODS: CT scans obtained in 45 patients were scored semiquantitatively for extent of five CT patterns, and the functional importance of each pattern was evaluated. RESULTS: The most prevalent CT patterns were decreased attenuation (n = 40), a reticular pattern (n = 37), and a nodular pattern (n = 36). At univariate and multivariate analyses, a reticular pattern was the main determinant of functional impairment, particularly airflow obstruction. The extent of a reticular pattern was independently associated with airflow obstruction, as shown by the inverse relationships with the forced expiratory volume in 1 second (FEV1) (P < .001), FEV1-forced vital capacity ratio (P < .01), maximum expiratory flow at 25% above residual volume (P < .001), and maximum expiratory flow at 50% above residual volume (P < .001) and the positive relationship with the residual volume-total lung capacity ratio (P < .001). CONCLUSION: In sarcoidosis, CT features compatible with small airways disease are common but contribute little to airflow obstruction, particularly in more advanced disease, which is characterized by an extensive reticular pattern. A reticular pattern at CT is the major morphologic association of airflow obstruction.     

Dose distribution in conventional CT and spiral CT and on the topic of dose reduction with spiral CT

We retrospectively analyzed patterns of emergency room visits by patients with exacerbations of asthma from December 1995 through November 1996. A total of 591 episodes in 198 patients were reviewed. The average age was 35.8 years, ranging from 15 to 71. The largest number of visits occurred in September. The number of visits per year ranged from 1 to 22; the mean was 2.9 per year. In patients who were followed on a regular basis at our institution, serve attacks accounted for 7.1% of the total, compared with 21.6 percent at other hospitals or outpatient clinics. We suspect that this difference was related to differences in the use of inhaled steroids. At our institution, 89% of patients were taking inhaled steroids; at other hospitals or clinics, only 21% were taking inhaled steroids. Of the 198 patients, 33 fulfilled one of the following criteria: (1) endotracheal intubation for respiratory failure or respiratory arrest, (2) respiratory acidosis (pH < 7.35) without endotracheal intubation; 27% of those patients had been given a diagnosis of mild asthma before the acute exacerbation. We conclude that patient education and standard guidelines for treatment of asthma, are very important for appropriate management of asthma, to prevent exacerbations and asthma-related deaths.     

Increasing spiral CT benefits with postprocessing applications

This paper reviews the current and future role of various postprocessing tools for epidemiologically important diseases. It introduces a generic business system for diagnosis and treatment using Spiral CT. Postprocessing of Spiral CT data should become a routine part of radiological practice. As viewing moves from film to monitor displays, interactive postprocessing tools support evaluation of CT studies and will in some cases also improve diagnostic accuracy. Track-ball controlled browsing through the volume data may be performed on axial images or on multiplanar reformats (MPR). These tools can be expected to become an integral part of most CT evaluations in the near future. Already now, MPR are important adjuncts for most orthopaedic applications. Presently, three-dimensional (3D) displays are used mainly in orthopaedic and trauma patients. In CT angiography, 3D surface displays and maximum intensity projections are routine display modalities. New volume rendering techniques (VRT) with interactive parameter changes will make 3D imaging of soft tissues feasible as well. The key input factor for many postprocessing applications will be Spiral CT data sets with high z-axis resolution (subsecond scanning, thin collimation, overlapping image reconstruction) and optimised application of contrast media. The most important benefit of postprocessing is the communication with the referring physician since 3D representations are becoming increasingly important for treatment planning and control. Postprocessing services will become a key ingredient of a successful radiological practice. If radiology does not provide it, the other physicians will do it themselves. For treatment simulation, virtual surgical instruments and tissue motion models are still in their infancy and will keep software architects and physicians busy for the next decade of Spiral-CT.     

Thoracic actinomycosis: CT findings

PURPOSE: To characterize computed tomographic (CT) findings of thoracic actinomycosis. MATERIALS AND METHODS: Chest CT scans and radiographs obtained in 22 patients with histopathologically proved thoracic actinomycosis were retrospectively reviewed. All patients were immunocompetent; they were aged 12-73 years (mean, 42.6 years; 14 male, eight female). CT findings were correlated with histopathologic findings in nine patients who underwent surgery (lobectomy [n = 8] or segmental resection [n = 1]). RESULTS: All of the lesions were unilateral, with an average diameter of 6.5 cm (range, 2-12 cm). Patchy air-space consolidation (n = 20) or a mass (n = 2) was seen on CT scans. Fifteen (75%) of the 20 patients with air-space consolidation had central areas of low attenuation (5-30 mm in diameter) within the consolidation. Thirteen of the 15 patients underwent contrast medium-enhanced CT. Ten (77%) of the 13 patients showed ring-like rim enhancement. Adjacent pleural thickening was seen in 16 patients (73%). At histopathologic examination, central low-attenuation areas at CT were seen as microabscesses with sulfur granules or a dilated bronchus that contained inflammatory cells and Actinomyces colonies. Peripheral enhancement of the low-attenuation areas was wall of the microabscess or surrounding parenchyma composed of granulation tissue rich in vascularity. CONCLUSION: Findings of chronic segmental air-space consolidation that contained low-attenuation areas with peripheral enhancement or adjacent pleural thickening at CT were suggestive of thoracic actinomycosis.     

Pulmonary Wegener''s granulomatosis: correlation between high-resolution CT findings and clinical scoring of disease activity

STUDY OBJECTIVE: To evaluate the usefulness of high-resolution CT (HRCT) for monitoring pulmonary disease activity in Wegener's granulomatosis (WG). DESIGN: Prospective study of CT and clinical data. SETTING: Main referral hospital for rheumatic diseases and department of diagnostic radiology of collaborating university hospital. PATIENTS: Seventy-three patients with WG underwent 98 staging examinations using HRCT. The status of pulmonary disease activity at the time of examination was scored according to clinical, bronchoscopic, BAL, and radiographic findings as follows: activity (n=25, group 1), past activity (n=45, group 2) and lack of any pulmonary disease (n=28, group 3). HRCT findings were correlated with the clinical scoring of pulmonary disease activity. RESULTS: Of 98 staging examinations 78 (79.6%) revealed abnormal CT scans showing the following main abnormalities: (a) nodules or masses (group 1: 16 [60.4%], group 2: 9 [20%]); (b) parenchymal bands (group 1: 12 [48%], group 2: 27 [60%], group 3: 6 [21.5%]); (c) septal thickening (group 1: 8 [32%], group 2: 6 [13.3%]); (d) parenchymal opacification (group 1: 7 [28%], group 2: 4 [8.9%]); and (e) pleural irregularity (group 1: 14 [56%], group 2: 22 [49%], group 3: 9 [32%]). Nodules/masses and areas of parenchymal opacification were significantly associated with florid disease activity of the lungs. Parenchymal bands and septal thickening were observed in both groups with pulmonary involvement, but statistical analysis revealed no significant difference. Pleural irregularities were nonspecific. CONCLUSION: HRCT may be a useful adjunct to clinical scoring of pulmonary disease activity in patients with WG and suspected lung involvement.     

Small cell and anaplastic prostate cancer: correlation between CT findings and prostate-specific antigen level

BACKGROUND: Increased activity of the renin-angiotensin system has been implicated in decreased long-term survival of renal allografts. Recent studies suggest that a deletion variant of the angiotensin-converting enzyme, associated with increased humoral and tissue activity of this enzyme, may be a risk factor for the development of diabetic nephropathy and the progression of IgA nephropathy. The present study was conducted to determine whether the deletion variant of the angiotensin-converting-enzyme gene influences the long-term outcome in renal-transplant recipients. METHODS: We examined the relationship between recipient angiotensin-converting-enzyme genotype and clinical outcome in patients with a surviving allograft of at least 10 years (median survival 156 months, n= 86). Patients with an allograft survival of less than 3 years served as controls (median survival 10.4 months, n=87). RESULTS: Genotype distribution in long-term renal allograft survivors (II, 18; ID, 41; DD, 27; qD, 0.55) was similar to that in the control group (II, 12; ID, 53; DD, 22; qD, 0.56), and there were no significant differences between the genotypic groups in either cases or controls. Long-term survivors were more often female (58 vs 38%) and less often hypertensive (67 vs 77%). Both recipient and donor age were markedly lower in the long-term survivor group, whereas number of HLA mismatches and cold ischaemia time were comparable between cases and controls. CONCLUSIONS: This study does not support the hypothesis that the angiotensin-converting-enzyme insertion/deletion polymorphism is an important determinant of long-term transplant survival in Caucasian patients undergoing renal transplantation.     

Pulmonary embolism: prospective comparison of spiral CT with ventilation-perfusion scintigraphy

PURPOSE: To compare prospectively the accuracy of spiral computed tomography (CT) with that of ventilation-perfusion scintigraphy for diagnosing pulmonary embolism. MATERIALS AND METHODS: Within 48 hours of presentation, 142 patients suspected of having pulmonary embolism underwent spiral CT, scintigraphy, and (when indicated) pulmonary angiography. Pulmonary angiography was attempted if interpretations of spiral CT scans and of scintigrams were discordant or indeterminate and intermediate-probability, respectively. RESULTS: In the 139 patients who completed the study, interpretations of spiral CT scans and of scintigrams were concordant in 103 patients (29 with embolism, 74 without). In 20 patients, intermediate-probability scintigrams were interpreted (six with embolism at angiography, 14 without); diagnosis with spiral CT was correct in 16. Interpretations of spiral CT scans and those of scintigrams were discordant in 12 cases; diagnosis with spiral CT was correct in 11 cases and that with scintigraphy was correct in one. Spiral CT and scintigraphic scans of four patients with embolism did not show embolism. Sensitivities, specificities, and kappa values with spiral CT and scintigraphy were 87%, 95%, and 0.85 and 65%, 94%, and 0.61, respectively. CONCLUSION: In cases of pulmonary embolism, sensitivity of spiral CT is greater than that of scintigraphy. Interobserver agreement is better with spiral CT.