Perceptions of community, social capital, and how they affect self-reported health: a multilevel analysis.

OBJECTIVES: The link between social capital and self-reported health has been widely explored. On the other hand, we know less about the relationship between social capital, community socioeconomic characteristics, and non-social capital-related individual differences, and about their impact on self-reported health in community settings. METHODS: Cross-sectional study design with a proportional sample of 7965 individuals from 20 US communities were analyzed using multilevel linear regression models, where individuals were nested within communities. The response rates ranged from 13.5% to 25.4%. RESULTS: Findings suggest that perceptions of the community and individual level socioeconomic characteristics were stronger predictors of self-reported health than were social capital or community socioeconomic characteristics. CONCLUSIONS: Policy initiatives aimed at increasing social capital should first assess community member's perceptions of their communities to uncover potential assets to help increase social capital.

Portrayal of radiology in a major medical television series: How does it influence the perception of radiology among patients and radiology professionals?

OBJECTIVES: To assess how the portrayal of Radiology on medical TV shows is perceived by patients and radiology professionals. METHODS: In this IRB-approved study with patient consent waived, surveys were conducted among adult patients scheduled for radiological examinations and radiology professionals. The questionnaire investigated medical TV watching habits including interest in medical TV shows, appearance of radiological examination/staff, radiology's role in diagnosis-making, and rating of the shows' accuracy in portraying radiology relative to reality. RESULTS: One hundred and twenty-six patients and 240 professionals (133 technologists, 107 radiologists) participated. 63.5 % patients and 63.2 % technologists rated interest in medical TV shows ≥5 (scale 1-10) versus 38.3 % of radiologists. All groups noted regular (every 2nd/3rd show) to >1/show appearance of radiological examinations in 58.5-88.2 % compared to 21.0-46.2 % for radiological staff appearance. Radiology played a role in diagnosis-making regularly to >1/show in 45.3-52.6 %. There is a positive correlation for interest in medical TV and the perception that radiology is accurately portrayed for patients (r = 0.49; P = 0.001) and technologists (r = 0.38; P = 0.001) but not for radiologists (r = 0.01). CONCLUSIONS: The majority of patients perceive the portrayed content as accurate. Radiologists should be aware of this cultivation effect to understand their patients' behaviour which may create false expectations towards radiological examinations and potential safety hazards. KEY POINTS: • Radiology in medical TV shows is conveyed as important in diagnosis making • Presence of radiological staff is less frequent compared to examinations shown • Positive correlation for interest in medical TV and radiology perceived as accurate • TV experience may create false expectations and potential safety hazards.

ESGAR consensus statement on liver MR imaging and clinical use of liver-specific contrast agents.

OBJECTIVES: To develop a consensus and provide updated recommendations on liver MR imaging and the clinical use of liver-specific contrast agents. METHODS: The European Society of Gastrointestinal and Abdominal Radiology (ESGAR) formed a multinational European panel of experts, selected on the basis of a literature review and their leadership in the field of liver MR imaging. A modified Delphi process was adopted to draft a list of statements. Descriptive and Cronbach's statistics were used to rate levels of agreement and internal reliability of the consensus. RESULTS: Three Delphi rounds were conducted and 76 statements composed on MR technique (n = 17), clinical application of liver-specific contrast agents in benign, focal liver lesions (n = 7), malignant liver lesions in non-cirrhotic (n = 9) and in cirrhotic patients (n = 18), diffuse and vascular liver diseases (n = 12), and bile ducts (n = 13). The overall mean score of agreement was 4.84 (SD ±0.17). Full consensus was reached in 22 % of all statements in all working groups, with no full consensus reached on diffuse and vascular diseases. CONCLUSIONS: The consensus provided updated recommendations on the methodology, and clinical indications, of MRI with liver specific contrast agents in the study of liver diseases. KEY POINTS: • Liver-specific contrast agents are recommended in MRI of the liver. • The hepatobiliary phase improves the detection and characterization of hepatocellular lesions. • Liver-specific contrast agents can improve the detection of HCC.

[Rational imaging of hepatocellular carcinoma. The challenge of multimodal diagnostic criteria]. / Rationale Schnittbildgebung des hepatozellulären Karzinoms. Die Herausforderung multimodaler Diagnosekriterien.

CLINICAL/METHODICAL ISSUE: Both computed tomography (CT) and magnetic resonance imaging (MRI) constitute the gold standard in radiological imaging of hepatocellular carcinoma (HCC). In cases of typical contrast behavior each modality as a single dynamic technique allows the diagnosis of HCC. There is still a challenge in detection of small HCCs < 2 cm, in differentiating HCC and high-grade dysplasia from other benign liver lesions as well as the evaluation of hypovascular liver lesions in the cirrhotic liver. PERFORMANCE: Nowadays, both modalities achieve high detection rates of 90-100 % for lesions > 2 cm. Regarding lesions between 1 and 2 cm there is a higher sensitivity for MRI ranging between 80 and 90 % compared to 60-75 % with CT. Besides the multimodal diagnostic criteria, MRI provides significant benefits with the use of hepatobiliary contrast. Especially in combination with diffusion- weighted imaging (DWI) increased sensitivity and diagnostic accuracy compared to CT has been described for lesions sized < 2 cm. Regarding the differentiation from other hepatic nodules in the cirrhotic liver there is strong evidence that the coexistence of arterial enhancement and hypointensity on hepatobiliary imaging is specific for HCC. Moreover, hypointensity on hepatobiliary imaging is associated with a high positive predictive value (PPV) of up to 100 % for the presence of high-grade dysplasia and HCC. ACHIEVEMENTS: The use of MRI including hepatobiliary imaging and DWI has to be regarded as the best non-invasive imaging modality for the detection of HCC and for the characterization of nodules in patients with liver cirrhosis. In comparison to CT there are benefits regarding detection of small lesions < 2 cm and evaluation of hypovascular liver lesions in the context of the hepatocarcinogenesis including prognostic values of premalignant lesions. PRACTICAL RECOMMENDATIONS: Both MRI and CT provide a high diagnostic performance in evaluation of HCC in liver cirrhosis. With MRI there are considerable advantages regarding the detection rate and specificity. For daily clinical routine, CT offers a fast, reliable and easy available modality with benefits for patients in reduced general state of health and restricted compliance.

Contrast-enhanced free-breathing 3D T1-weighted gradient-echo sequence for hepatobiliary MRI in patients with breath-holding difficulties.

OBJECTIVE: Evaluate the image quality and diagnostic performance of a free-breathing 3D-gradient-echo sequence with radial acquisition (rGRE) compared with a Cartesian breath-hold 3D-GRE (cGRE) sequence on hepatobiliary phase MRI in patients with breath-holding difficulties. METHODS: Twenty-eight consecutive patients (15 males; mean age 61 ± 11.9 years) were analysed in this retrospective IRB-approved study. Breath-holding difficulties during gadoxetate-disodium-enhanced liver MRI manifested as breathing artefacts during dynamic-phase imaging. MRI included axial and coronal cGRE and a radially sampled rGRE sequence during the hepatobiliary phase. Two radiologists independently evaluated cGRE and rGRE images for image quality, liver lesion detection and conspicuity, and bile duct conspicuity on a four-point scale. RESULTS: Liver edge sharpness was significantly higher on rGRE images (P < 0.001). Overall image quality was slightly but significantly higher for rGRE than for cGRE (P < 0.001 and P = 0.039). Bile duct conspicuity scores of rGRE and cGRE were not significantly different. Sensitivity for detection of the 26 liver lesions was similar for rGRE and cGRE (81-77 % and 73-77 %, P = 0.5 and 1.0). Lesion conspicuity scores were significantly higher for rGRE for one reader (P = 0.012). CONCLUSION: In patients with breath-holding difficulties, overall image quality and liver lesion conspicuity on hepatobiliary phase MRI can be improved using the rGRE sequence. KEY POINTS: • Patients with diminished breath-holding capacities present a major challenge in abdominal MRI. • A free-breathing sequence for hepatobiliary-phase MRI can improve image quality. • Further advances are needed to reduce acquisition time of the free-breathing gradient-echo sequence.

Epithelial cells in bone marrow of breast cancer patients at time of primary surgery: clinical outcome during long-term follow-up.

PURPOSE: To evaluate the detection of epithelial cells in bone marrow of breast cancer patients as an indicator of metastatic disease. PATIENTS AND METHODS: Between 1989 and 1994, bone marrow biopsies were performed on 393 breast cancer patients during primary surgery. Specimens were stained immunocytochemically for epithelial cells expressing cytokeratins or the epithelial membrane antigen. The long-term outcomes of these patients were analyzed in this study. RESULTS: In 166 of 393 patients, epithelial cells were found in bone marrow (BM) aspirates. These patients were designated BM+. The rate of tumor recurrence or cancer-related death was significantly higher in BM+ patients than in BM- patients. Multivariate analysis using the Cox regression model revealed BM status as a prognostic parameter independent of tumor size and axillary lymph node status. However, tumor size and axillary lymph node status were clearly superior prognostic parameters. CONCLUSION: Disseminated epithelial cells in BM are associated with poor clinical outcome in breast cancer patients. However, the presence of these cells is not a sufficient parameter to predict growing metastases in the majority of patients, suggesting that epithelial cells in the BM of breast cancer patients at the time of surgery have limited metastatic potential. The role of these cells needs to be further evaluated.

Dose-dense doxorubicin, docetaxel, and granulocyte colony-stimulating factor support with or without tamoxifen as preoperative therapy in patients with operable carcinoma of the breast: a randomized, controlled, open phase IIb study.

PURPOSE: To investigate the effect of adding tamoxifen to a preoperative dose-dense doxorubicin and docetaxel regimen on the pathologic response of primary operable breast cancer. PATIENTS AND METHODS: Patients (tumor size > or = 3 cm, N0 to 2, M0) were prospectively randomized to receive every 14 days a total of four cycles of doxorubicin 50 mg/m2 and docetaxel 75 mg/m(2), either with (ADocT) or without (ADoc) simultaneous tamoxifen. Granulocyte colony-stimulating factor (G-CSF) was routinely given on days 5 to 10. Surgery followed 8 to 10 weeks after the start of treatment. RESULTS: Within 14 months, 250 patients were included in the study at 56 centers. Of 992 planned cycles, 97.9% were administered. Pathologically complete remission (pCR) with no detectable viable tumor cells was achieved in 9.7%. There was a nonsignificant difference of -1.2% in favor of ADoc, with a 95% confidence interval of -8.6% to 6.2%. A further 2.4% had only noninvasive tumor residues, and 13.8% had focal invasive residues. Complete and partial responses detected by palpation were observed in 28.9% and 52.4%, respectively. The response rates (complete and partial) by best appropriate imaging methods were 77.5% and 67.5% for ADocT and ADoc, respectively. Breast conservation was possible in 68.8% of the patients. A tendency toward more frequent toxic events was observed with ADocT treatment. Significant predictors of pCR to chemotherapy were negative lymph node and negative estrogen receptor status. CONCLUSION: A dose-dense regimen of ADoc with G-CSF offers high compliance, moderate toxicity, and rapid efficacy as a form of preoperative chemotherapy in operable breast cancer. Concurrent treatment with tamoxifen for 8 weeks could not improve the pathologic response rate.

Computed high b-value diffusion-weighted imaging improves lesion contrast and conspicuity in prostate cancer.

BACKGROUND: To evaluate whether very high b-value computed diffusion-weighted imaging (cDWI) is able to provide better contrast between the foci of prostate cancer and background tissue than the standard apparent diffusion coefficient (ADC) map, and whether this improved contrast could be used to improve the tumor detection. METHODS: Very high b-value cDWI series up to b4000 were created for 14 patients with high-grade prostate cancer. Contrast-to-noise ratios (CNRs) and CNR-to-ADC ratios were calculated. Three blinded readers also assessed the tumor conspicuity on a standard five-point scale. RESULTS: The tumor CNR increased with increasing b-values in all the patients up to a maximum average CNR of 75.1 for a b-value of 4000 (average CNR for the ADC maps: 10.0). CNR/ADC ratios were higher than 1 (indicating higher CNR than respective ADC) for cDWI of 1500 and higher, with a maximum of 6.5 for cDWI4000. The average subjective tumor conspicuity scores for cDWI2000, 3000 and 4000 were significantly higher than that of the ADC (4.0): 4.5 (P=0.018), 4.5 (P=0.017) and 4.6 (P=0.012). CONCLUSIONS: cDWI is able to provide better contrast between the foci of prostate cancer and background tissue compared with a standard ADC map. This resulted in improved subjective tumor conspicuity.

Factors influencing the prognostic role of oestrogen and progesterone receptor levels in breast cancer--results of the analysis of 670 patients with 11 years of follow-up.

In the last two decades, the prognostic role of the steroid hormone receptors has been the subject of a myriad of publications. Nevertheless, its relevance after long-term follow-up is still not clear. The confusion about the prognostic value is mainly due to the difficulty in comparing analyses. Despite different study-designs and statistical approaches, oestrogen (ER) and progesterone (PR) receptors are widely accepted as prognostic factors. Data from 670 breast cancer patients with a median follow-up of 11.4 years were analysed retrospectively. ER and PR were measured by the dextran-coated charcoal (DCC) assay. To investigate the time dependence of the prognostic relevance of ER and PR, separate analyses were done for follow-up shorter and longer than 5 years. Special focus was directed at patients < or =50 and >50 years, node-negative women, in particular those without adjuvant therapy. Univariate and multivariate analyses were performed. In univariate analysis, ER and PR were associated with a significantly longer overall survival at the cut-off levels 10, 20 or 100 fmol/mg protein. The significant survival benefit occurred in the first 5 years of follow-up and remained unchanged in the following period. In the multivariate analyses, only the PR was of significant prognostic value (for PR> or =20 fmol/mg P=0.036, for PR> or =100 P=0.01, Cox analysis). In patients younger than 51 years, only PR was an independent prognosticator at the cut-off level of 100 fmol/mg protein, while in patients >50 years both hormone receptors were not significant. In N0 patients, only the PR reached long-term prognostic independence at a cut-off point of > or =100 fmol/mg (P=0.018). In addition, in the group of node-negative women < or =50 years without adjuvant therapy the PR level reached prognostic significance. The hormone receptor status was a prognostic factor only during the first 5 years of follow-up. Our data suggest that age, lymph node status, length of follow-up and probably the ER/PR assay are important for the evaluation of ER and PR as prognostic variables. In most analyses, PR appeared to be superior to ER in predicting the prognosis of primary breast cancer patients.

The role of docetaxel (Taxotere) in neoadjuvant chemotherapy of breast cancer.

Neoadjuvant chemotherapy has become standard therapy in the management of breast cancer patients with locally advanced disease with inoperable tumors and inflammatory breast cancer. Patients with earlier stage breast cancer and operable tumors may also benefit from treatment with neoadjuvant chemotherapy. Docetaxel (Taxotere; Rhône-Poulenc Rorer, Collegeville, PA) is thought to be one of the most potent agents in the treatment of metastatic breast cancer and is therefore being investigated for its likely benefit in preoperative, neoadjuvant regimens. Several large phase II and randomized phase III trials are evaluating docetaxel as a single agent, in combination, and/or sequentially in the preoperative setting. Preliminary findings demonstrate high complete and partial response rates and a tolerable toxicity profile. These results are consistent with the view that incorporation of docetaxel in neoadjuvant chemotherapy regimens will contribute to improved patient outcome. Ongoing studies will provide important information regarding the most appropriate regimens and schedules of docetaxel to use in the preoperative, neoadjuvant setting.

Usefulness of FDG-PET in diagnosing primary lymphoma of the liver.

This case report shows for the first time the usefulness of positron emission tomography (PET) with 2-[18F]-fluoro-2-deoxy-D-glucose (FDG) in the diagnosis of primary non Hodgkin's lymphoma of the liver. Results of FDG-PET, which in contrast to other imaging techniques offers the advantage of screening the whole body, demonstrated a high glycolytic activity of a solitary mass in the liver with central necrosis (loss of glycolytic activity), but no spread of lymphoma to the body. These results were confirmed by ultrasound, computed tomography, magnetic resonance imaging and were biopsy proven. From our findings we conclude that in patients with liver masses with high uptake of FDG, lack of liver dysfunction and absence of signs indicating other malignancies, a primary lymphoma of the liver should be considered as a possible diagnosis.

In vitro activity of human chorionic gonadotropin (hCG)--doxorubicin conjugates against ovarian cancer cells.

BACKGROUND: Despite radical surgery and the introduction of novel chemotherapeutic agents, the prognosis of ovarian cancer remains poor. Since in the past the potential role of gonadotropins in the induction and progression of ovarian cancer has been discussed, we conjugated doxorubicin to human chorionic gonadotropin (hCG) in order to specifically target ovarian cancer cells. MATERIALS AND METHODS: Doxorubicin was conjugated to hCG via glutaraldehyde. 48 hours post seeding, NIH:OVCAR 3 cells were treated with various concentrations of hCG-conjugated and non-conjugated doxorubicin for 2 hours. Cells were cultured for a total of 168 hours. Cell growth was monitored by a crystal violet assay. RESULTS: Conjugating doxorubicin to hCG resulted in an average specific uptake of 22 mol doxorubicin per mol protein (range 3.0-43.3 mol). Incubating NIH:OVCAR 3 cells for 2 hours with the conjugate led to a more than 8 fold increase of the IC50 values compared to non-conjugated doxorubicin (0.55 microM versus 4.43 microM). The antiproliferative activity of both conjugated and free doxorubicin was detectable up to 168 hours post treatment. CONCLUSIONS: The present experiments clearly demonstrate a more than 8-fold increase in cytotoxicity of the conjugates compared to free doxorubicin. It was also shown that this effect was not restricted to an acute toxic event but that it resulted in a prolonged antiproliferative activity.

CA 125 production and release by ovarian cancer cells in vitro.

The antigenic determinant CA 125 is a high molecular weight glycoprotein which is elevated in more than 80% of patients with epithelial ovarian cancer. Despite its good performance as a human tumor marker, only little is known about its physiological function. According to recent publications, CA 125 production and release appear to be related to cellular growth. In order to investigate this putative relationship more closely, we analyzed the pattern of CA 125 production and release by ovarian cancer cells during exponential cell growth, during cell cycle arrest by colchicine and during inhibition of cellular protein synthesis by cycloheximide. The results were correlated with the cell cycle distribution. According to our results, the main determinant of CA 125 release into the culture supernatant is the total cell count. Although cell cycle arrest in the G2 + M phase by means of colchicine treatment resulted in the death of most cells, which was reflected by an increased release of CA 125, no differences in the intracellular production rate between colchicine treated and untreated cells were seen. In contrast, treatment of cells with cycloheximide not only resulted in decreasing cell numbers but also in a complete inhibition of CA 125 production by surviving cells.

Percutaneous magnetic resonance image-guided biopsy and aspiration in the head and neck.

OBJECTIVE/HYPOTHESIS: To test the hypotheses that 1) magnetic resonance imaging (MRI)-guided biopsy and aspiration with an open 0.2-T system (Magnetom Open, Siemens, Erlangen, Germany) in the head and neck is feasible and successful and 2) procedure times can be sufficiently short to be well tolerated by the patient. METHODS: Sixty-one MRI-guided procedures were performed in 47 patients (ages, 6 mo-88 y) in the head and neck, including the mucosal sites and masticator and parapharyngeal spaces (n = 23), parotid space (n = 6), submandibular space (n = 2), cervical vertebral column/paraspinal tissues (n = 8), skull base (n = 3), larynx or hypopharynx (n = 3), and infrahyoid nodal chains and surrounding tissues (n = 16). A clinical C-arm imaging system was used, supplemented by an in-room radiofrequency-shielded liquid crystal monitor, rapid gradient echo sequences for needle guidance, and MRI-compatible anesthesia, monitoring, and surgical lighting equipment. Tissue sampling included fine-needle aspiration (n = 58) and cutting-needle core biopsy (n = 27), with 24 patients undergoing both procedures. Procedures were evaluated for success of needle placement, procedure time, and complications. RESULTS: Successful needle placement was accomplished in all cases without complication, with tissue sufficient for pathological diagnosis obtained for all but five patients with an average of 2.1 passes per patient. For fine-needle aspiration, average instrument time was 7.8 minutes per pass, and average cutting-needle core biopsy time was 9.2 minutes. CONCLUSIONS: Interactive MRI guidance for needle biopsy and aspiration of deep head and neck lesions is feasible, successful, and safe. Procedure times are sufficiently short to be well tolerated by the patient.

Computer assisted determination of the dose-area product in retrograde urethrography.

Retrograde urethrography (RUG) is a dynamic radiological procedure in which the cumulative dose-area product (DAP) comprises radiation doses derived from both fluoroscopy and radiography. In the present prospective study, digital retrograde urethrographs (Prestilix 1600X/DRS, General Electric) were obtained in 40 consecutive male patients (mean age 60.6 years; range 23-88 years) presenting for evaluation of urinary pathology. The radiation dose was recorded as the dose-area product. From these data, a computer program (Diasoft 2.0, PTW, Freiburg, Germany) then determined the respective proportions of the total radiation dose deriving from fluoroscopy and radiography, as well as the number of radiographic exposures. The average total radiation dose was 316 cGy cm2. In five of the 40 patients examined (12.5%), the number of radiographic exposures registered by the program and, hence, the calculated DAPs were erroneous. In the remaining 35 patients, the average proportion of the cumulative DAP resulting from fluoroscopy was 81%, while that deriving from radiography was 19%. The computer program utilized in this study makes possible an intelligent evaluation of the DAP in dynamic procedures such as RUG. Since fluoroscopy is responsible for 81% of the cumulative DAP at RUG, a significant decrease in applied radiation dose may be achieved by reducing fluoroscopy time or by using pulsed fluoroscopy.

Metastases to the pancreas.

Disparity in prognosis and management between primary and secondary pancreatic tumours makes recognition of metastases to the pancreas on CT and MRI an important goal. Three different patterns of secondary pancreatic tumours may be seen: localized, multifocal, or diffuse enlargement. CT findings include hypodense lesions, which show rim enhancement following intravenous contrast medium. On MR examination, the lesions are usually hypointense on T1 weighted and hyperintense on T2 weighted images.

The average dose-area product at intravenous urography in 205 adults.

The intravenous urography (IVU) is the most important and most frequently performed radiological examination in urology. This prospective study determined the dose-area product as a measurement of radiation dose in 205 adult patients undergoing IVU. Average dose-area product was 1017 cGy cm2. An average 3.7 radiographs were obtained per patient. Tomographic views were required in only 8.8% of cases. Radiation dose is dependent not only on the number and size of the obtained radiographs, but on the physical constitution of the patient. The dose-area products measured show a clear relationship to the body weight of the patient.

Effect of iodine concentration of contrast media on contrast enhancement in multislice CT of the pancreas.

The purpose of this study was to determine the influence of two different iodine concentrations of the non-ionic contrast agent, Iomeprol, on contrast enhancement in multislice CT (MSCT) of the pancreas. To achieve this MSCT of the pancreas was performed in 50 patients (mean age 57+/-14 years) with suspected or known pancreatic tumours. The patients were randomly assigned to group A (n=25 patients) or group B (n=25 patients). There were no statistically significant differences in age, height or weight between the patients of the two groups. The contrast agent, Iomeprol, was injected with iodine concentrations of 300 mg ml(-1) in group A (130 ml, injection rate 5 ml s(-1)) and 400 mg ml(-1) in group B (98 ml, injection rate 5 ml s(-1)). Arterial and portal venous phase contrast enhancement (HU) of the vessels, organs, and pancreatic masses were measured and a qualitative image assessment was performed by two independent readers. In the arterial phase, Iomeprol 400 led to a significantly greater enhancement in the aorta, superior mesenteric artery, coeliac trunk, pancreas, pancreatic carcinomas, kidneys, spleen and wall of the small intestine than Iomeprol 300. Portal venous phase enhancement was significantly greater in the pancreas, pancreatic carcinomas, wall of the small intestine and portal vein with Iomeprol 400. The two independent readers considered Iomeprol 400 superior over Iomeprol 300 concerning technical quality, contribution of the contrast agent to the diagnostic value, and evaluability of vessels in the arterial phase. No differences were found for tumour delineation and evaluability of infiltration of organs adjacent to the pancreas between the two iodine concentrations. In conclusion the higher iodine concentration leads to a higher arterial phase contrast enhancement of large and small arteries in MSCT of the pancreas and therefore improves the evaluability of vessels in the arterial phase.

Virtual cystoscopy based on helical CT scan datasets: perspectives and limitations.

The purpose of the study was to simulate cystoscopy based on three-dimensional helical CT scan datasets in real-time in patients with tumours of the urinary bladder. A helical CT scan with double detector technology was carried out pre-operatively in 11 patients with histologically confirmed carcinoma of the urinary bladder and one patient with chronic cystitis. A non-enhanced scan was first performed, followed by an examination in the early phase of contrast medium enhancement. Further images were acquired after adequate filling of the bladder with contrast medium, approximately 30 min after injection. These data were transferred to a separate graphic computer workstation and reconstructed. The results were then compared with the cystoscopic and histopathological findings. All tumours of the urinary bladder identified at fibreoptic cystoscopy were shown on virtual cystoscopy. The best reconstruction results were obtained from data acquired 30 min after injection of contrast medium. The ureteric orifices were not visualized at virtual cystoscopy. These data lead us to conclude that, at present, virtual cystoscopy has not reached the quality of fibreoptic examination and remains restricted to use in specific cases, for example patients with urethral strictures.

Comparison of a modified Kjeldahl and a vacuum fusion technique for determination of nitrogen in tantalum alloys.

Results obtained for the determination of nitrogen in the tantalum alloys T-111 (Ta-8 W-2 Hf) and T-222 (Ta-10 W-2.5 Hf-0,1C) by Kjeldahl and vacuum fusion procedures are compared. Results obtained by each technique are shown for the determination of nitrogen m the MAB T-111 sample, two commercial T-111 samples and a commercial sample of T-222 alloy. In the 5-25 ppm range, the relative standard deviation was 3-9% by the Kjeldahl procedure and 4-8% by vacuum fusion. This is a measure of the homogeneity of the material as well as of the reproducibility of the results. The agreement of the results obtained by these two techniques increases confidence in the vacuum fusion results for nitrogen in tantalum.