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.

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.

[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.

[Symptom-oriented follow-up of early breast cancer compared to intensive surveillance. Results of a prospective multicentre study: update and 10-year overall survival]. / Symptomorientierte Nachsorge nach Mammakarzinom im Vergleich zur intensiv-apparativen Nachsorge. Ergebnisse einer prospektiven multizentrischen Studie: Update und 10-Jahres-Überlebenszeit.

BACKGROUND AND OBJECTIVE: In a prospective, non-randomised, multicentre cohort study we compared intensive surveillance to symptom-oriented control in the follow-up of patients with early breast cancer after curative surgical treatment. Five-year overall survival had shown that symptom-oriented follow-up was not inferior to intensive control. However, a more intensive, instrumental based follow-up is still claimed by many patients and their physicians. In this context the recent data of 10-year overall survival (OS) are reported. PATIENTS AND METHODS: In the prospective, non-randomised, multicentre cohort study carried out between 1995 and 2000, 244 patients underwent an intensive follow-up (scheduled laboratory tests including CEA and CA 15-3, chest X-rays and liver ultrasound). 426 patients were monitored in a symptom-oriented manner (additional tests only in the case of symptoms indicating possible recurrence). Mammography, structured histories and physical examinations were done regularly in both groups. RESULTS: In the clinical follow-up group, 90 deaths (21.2 %) were observed with an estimated 10-year overall survival rate of 83.0 % (95 % CI 79.1 -86.3 %).  In the intensive follow-up group, 59 deaths (24.2 %) were observed with an estimated 10-year overall survival rate of 78.5 % (95 % CI 72.6 -83.2 %). The Cox proportional hazards model for OS includes the variables follow-up form, stage of primary tumor and lymph nodes, hormone receptor status, grading and age at diagnosis. This model resulted in a hazard ratio of 1.10 (95 % CI 0.78-1.54) for the follow-up protocol (intensive vs. clinical). Welleks' test for non-inferiority showed that clinical follow-up is not inferior in comparison to intensive follow-up (p < 0.05) for a non-inferiority limit of + 7 % at 10-years. CONCLUSION: This analysis of 10-year overall survival of patients with early breast cancer after curative primary treatment confirms that follow-up without regular imaging and laboratory tests is not inferior in the sense of a relevant higher mortality. To what extent new concepts in the treatment of breast cancer have any influence on follow-up care has to be examined in further studies.

Case report. Spontaneous cholecystocolic fistula and locoregional liver tumour ablation: a cautionary tale.

A liver abscess is a feared and potentially fatal complication following transarterial chemoembolisation (TACE) and radiofrequency ablation (RFA) of liver tumours. Iatrogenic bilio-enteric communications, such as bilio-enteric anastomosis, sphincterotomy and biliary stents, are considered major risk factors and are due to bacterial colonisation of the biliary tree with enteric flora. Naturally occurring spontaneous cholecysto-enteric fistula poses a similar risk as its iatrogenic counterparts but is rarely described in the literature. We present a case where abscess formation complicated a combined TACE and RFA in an unrecognised cholecystocolic fistula.

Cycle control, tolerability, efficacy and acceptability of the vaginal contraceptive ring, NuvaRing: results of clinical experience in Germany.

OBJECTIVES: To investigate the real-life clinical experience of NuvaRing users in Germany. METHODS: An open-label, prospective, uncontrolled, non-randomized, multicentre postmarketing surveillance study was conducted by 1204 gynaecologists amongst 5823 women requesting contraception. The women underwent routine examinations and contraceptive counselling, and were assessed after three and six cycles of NuvaRing use. RESULTS: Good cycle control was observed and there was a reduction in cycle irregularity and inter-menstrual bleeding, bleeding duration and intensity, and dysmenorrhoea. NuvaRing was well tolerated, and had no significant effect on body weight or blood pressure. Nine women became pregnant unintentionally (two had conceived before they started to use NuvaRing, three due to non-compliance, one because of repeated ring expulsion/loss and three during treatment in spite of having applied this latter as instructed). Most women expressed their satisfaction with NuvaRing; 82% were 'very satisfied/ satisfied', 72% planned to continue using it and 82% would recommend it to others. More than 90% of women found NuvaRing 'without problems/easy' to insert and to remove, and more than 80% of the women and their partners were not disturbed by its presence during intercourse. CONCLUSION: NuvaRing is a highly effective and acceptable method of once-monthly contraception that is safe and well tolerated.

3.0- Versus 1.5-T MR cholangiography: a pilot study.

OBJECTIVE: The purpose of our study was to evaluate quantitative and qualitative image quality of MR cholangiography at a field strength of 3.0 T compared with the standard field strength of 1.5 T. MATERIALS AND METHODS: A standardized MR cholangiography sequence protocol was used for 15 healthy male volunteers (mean age +/- SD, 32.4 +/- 4.3 years) who underwent both 1.5- and 3.0-T MRI within 2 hr in an alternating fashion. Dedicated circular polarized torso coils (1.5 and 3.0 T) were used. The sequence protocol included breath-hold single-slice rapid acquisition with relaxation enhancement (slice thickness, 50 mm; orientation, coronal and +/- 20 degrees oblique coronal); breath-hold multislice HASTE (slice thickness, 3 mm; coronal only); and a non-breath-hold, respiratory-triggered 3D turbo spin-echo (TSE) T2-weighted sequence (slice thickness, 1 mm; 60 slices per slab; coronal only). Maximum intensity projections were generated from each multislice data set. Bile duct (common bile duct, right posterior segmental branch, and left hepatic duct) to periductal tissue contrast-to-noise ratios were compared at 1.5 and 3.0 T. Qualitative image analysis was performed by three independent reviewers. Qualitative analysis included delineation of the extra- and intrahepatic biliary anatomy, with specific attention given to the presence (or absence) of cystic or intrahepatic ductal variants, using a 4-point confidence scale. Statistical analysis consisted of the paired Student's t test and the signed rank test. RESULTS: Contrast-to-noise ratios between the bile duct and the periductal tissue were higher at 3.0 T in all three locations (common bile duct, right posterior segmental branch, and left hepatic duct). In each magnet class, the 3D TSE sequence offered the best contrast-to-noise ratio and qualitative analysis. Superiority of the 3D TSE sequence was statistically significant in all analyses. Five of the 15 volunteers had intrahepatic biliary variants that were detected with a higher level of confidence (p < 0.01) on the 3.0-T system than on the 1.5-T system. CONCLUSION: Compared with MR cholangiography at 1.5 T, MR cholangiography at 3.0 T offers improved contrast-to-noise ratio and a higher level of confidence for depicting intrahepatic variants.

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.

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.

[Preoperative chemotherapy in primary operable breast cancer with a dose-dense combination of doxorubicin and docetaxel (ADoc) - Experience of the GEPARDO-GABG study group]. / Präoperative Chemotherapie operabler primärer Mammakarzinome mit einer dosisdichten Kombination von Adriamycin und Docetaxel (ADoc) - Die Erfahrungen der GEPARDO-GABG-Studiengruppe -

OBJECTIVE: The German Adjuvant Breast Cancer Study Group (GABG) conducts trials of preoperative chemotherapy in patients with primary breast cancer using a combination of doxorubicin and docetaxel (ADoc). - PATIENTS AND METHODS: We conducted a parallel-grouped phase IIa-study with 42 patients with a conventionally dosed and a dose-dense ADoc-schedule (4 cycles of Doxorubicin 50 mg/m(2), Docetaxel 75 mg/m(2) i. v. day 1, q day 15 or 22; G-CSF day 3-15 only for the dose-dense schedule) and a randomized phase IIb-study (GEPARDO-Study) with 250 patients with ADoc +/- Tamoxifen. Biological factors were determined immunohistochemically on 197 core biopsies before treatment. A comparison to a sequential AC-Doc regimen including 913 patients has been completed recently. - RESULTS: ADoc can be applicated on schedule in 93 % of all patients. The dose-dense regimen shows a tendency to more toxicity but also to more efficacy. The rate of complete pathological remissions (pCR) was 9.7 %. No difference was found between chemo- and chemoendocrine treatment. Clinically negative lymphnodes and a negative estrogen receptor status is predictive for a higher pCR-rate. To date no differences in toxicity could be found between ADoc and AC-Doc. - CONCLUSIONS: The dose-dense ADoc regimen is well tolerated and highly effective as preoperative therapy of breast cancer.

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.

MR imaging-guided radiofrequency thermal ablation in the porcine brain at 0.2 T.

The aim of this study was to test the hypotheses that (a) MR imaging-guided radiofrequency (RF) thermal ablation is safe and feasible in porcine brain using an open C-arm-shaped low-field MR system, and that (b) induced thermal lesion size can be predicted using low-field MR imaging. Magnetic resonance-guided RF ablation was performed in the cerebral frontal lobes of six pigs. An 18-G monopolar RF electrode was inserted into the porcine brain using MR image guidance and RF was then applied for 10 min. After post-procedure imaging (T2-weighted, T1-weighted before and after gadodiamide administration), the pigs were killed and the brains were used for pathologic examination. Successful RF electrode placement was accomplished in all cases without complications; total magnet time ranged from 73 to 189 min. The thermal lesion size varied from 10 to 12 mm perpendicular to the electrode track and was easily visualized on T2-weighted and enhanced T1-weighted images. Enhanced T1-weighted imaging demonstrated the highest brain-to-RF thermal lesion contrast-to-noise ratio with an average of 1.5 +/- 1.6. Enhanced T1-weighted imaging never underestimated pathologic lesion diameter with a mean difference of 2.3 +/- 1.0 mm and a radiologic/pathologic correlation of 0.69. Magnetic resonance imaging-guided RF thermal ablation is feasible and safe in the porcine brain using an open MR low-field system. Induced-thermal lesion size can best be monitored using enhanced T1-weighted images. In the future, RF ablation under low-field MR guidance may offer an alternative treatment option for primary and secondary brain tumors.

[Comparison of susceptibility artefacts of different radiofrequency electrodes at O.2 T. Influence of electrode positioning, pulse sequence and image reconstruction methods]. / Vergleich der Suszeptibilitätsartefakte unterschiedlicher Radiofrequenzelektroden bei 0,2 T. Einfluss von Elektrodenlegierung, Pulssequenz und Bildrekonstruktionsmethode.

PURPOSE: Interventional MRI procedure monitoring requires small but accurate susceptibility artifacts of the instruments used. In this investigation, susceptibility artifacts of different RF-electrode designs were compared using a variety of pulse sequences and k-space acquisition methods. METHODS: 4 different 18-gauge RF-electrodes (with three single electrodes made of stainless steel, copper, inconal, and a triple-clustered electrode configuration made of inconal) were placed in a 0.2 T MR-scanner perpendicular to the main magnetic field. Pulse sequences used included: TSE T2, FISP, true-FISP, PSIF, and a temperature sensitive ES-GRE sequence. In addition to the 2D Cartesian k-space trajectory with Fourier transformation (2DFT), projection reconstruction (PR) was used with the FISP, true-FISP and PSIF sequences. RESULTS: The best tip accuracy was achieved with the combination of inconal electrodes and TSE T2. The usefulness of the tested sequences was found to be: TSE T2 > PSIF > FISP/true-FISP > ES-GRE. In general 2DFT provided better or equal tip accuracy than PR. The apparent shaft width was smaller using the copper electrode compared to the inconal electrode. However, the "match shaped" tip artifact of the copper probe led to a higher error in tip accuracy. CONCLUSIONS: TSE-T2 sequences and Cartesian 2DFT acquisitions should be used for accurate tip positioning at 0.2 T. Further, artifact size of the electrode shaft prevents the use of inconal for temperature sensitive sequences. Copper electrodes can be used for these purposes, although copper is not considered to be biocompatible at present.

Ability of MR cholangiography to reveal stent position and luminal diameter in patients with biliary endoprostheses: in vitro measurements and in vivo results in 30 patients.

OBJECTIVE: Our goal was to evaluate the ability of MR cholangiography to show stent position and luminal diameter in patients with biliary endoprostheses. MATERIALS AND METHODS: Susceptibility artifacts were evaluated in vitro in three different stent systems (cobalt alloy-based, nitinol-based, and polyethylene) using two breath-hold sequences (rapid acquisition with relaxation enhancement, half-Fourier acquisition single-shot turbo spin echo) on a 1.5-T MR imaging system. The size of the stent-related artifact was measured, and the relative stent lumen was calculated. In vivo stent position and patency were determined in 30 patients (10 cobalt alloy-based stents, five nitinol-based stents, and 15 polyethylene stents). RESULTS: In vitro, the susceptibility artifact of the cobalt stent caused complete obliteration of the stent lumen. The relative stent lumens of the nitinol-based and polyethylene stents were 38-50% and 67-100%, respectively. In vivo, all stents were patent at the time of imaging. The position of the cobalt alloy-based stent could be determined in nine of 10 patients, but stent patency could not be evaluated. Stent position of nitinol stents could not be adequately evaluated in any of the five patients, and internal stent diameter could be visualized in only one patient. In nine of 15 patients, the fluid column within the implanted polyethylene stent was seen on MR cholangiography. CONCLUSION: The internal stent lumen could be visualized in most patients with an indwelling polyethylene stent, but not in patients with cobalt alloy- or nitinol-based stents.

How does alteration of hepatic blood flow affect liver perfusion and radiofrequency-induced thermal lesion size in rabbit liver?

The purpose of this study was to test the hypothesis that decreasing liver perfusion in rabbits results in an increase in thermal lesion size and that these effects can be accurately monitored using magnetic resonance imaging (MRI). We additionally tested the hypothesis that the increase in thermal lesion size would depend on the particular vessel or vessels occluded (hepatic artery, portal vein, or both). Using an Institutional Animal Care and Use Committee approved protocol, 20 New Zealand white rabbits were randomly assigned to four treatment groups (five in each group): control and ligation of portal vein (PV), hepatic artery (HA), or both PV and HA (HAPV). Surgical ligation of the appropriate vessel was performed under general anesthesia. Immediately after ligation, the rabbits were placed in a 0.2-T open MR system, and an 18-G copper radiofrequency (RF) electrode with a 2-cm exposed tip was inserted into the liver. RF was applied for 10 minutes with the tip temperature maintained at 90 degrees +/- 2 degrees C. Before and after ablation, perfusion data were obtained for 90 seconds using 30 3-second sequential single oblique-slice fast imaging with steady-state progression (FISP) acquisitions after injection of gadolinium-diethylene triamine pentaacetic acid (Gd-DTPA) via the inferior vena cava. Postablation scanning included axial and oblique turbo spin-echo (TSE) T2-weighted (T2w), STIR, and Gd-enhanced T1w sequences. Lesion size was determined perpendicular to the RF electrode using software calipers on the imager. The rabbits were sacrificed after completion of the post-therapy scans, and their livers were harvested for histologic analysis. The liver showed a mean increase in signal amplitude (SA) of 76% 24 seconds after Gd contrast injection in the control group. After contrast injection, the SA increased to a mean of only 66% in the group with ligated hepatic arteries, with no difference in the time to peak compared with the control group. No significant SA increase over baseline could be found in the groups with ligated PV or ligated PV and HA. T2-weighted images demonstrated the highest lesion-to-liver contrast-to-noise ratios (CNRs; mean -5.5) on postprocedure images, followed by STIR images (mean -2.2) in the control group. The lesions were poorly delineated on the Gd-enhanced images. Average maximum lesion sizes (mean +/- 95% confidence interval) were 22 +/- 4.3 mm after ligation of PV, 22 +/- 2.6 mm after ligation of both PV and HA, 14 +/- 2.0 mm after ligation of HA, and 13 +/- 1.9 mm in the control group. We accept the hypothesis that the diameter of the region of coagulation necrosis achieved by standardized RF ablation in the liver increases with reduced organ perfusion and that this effect can be accurately monitored using MRI. The major factor influencing the size of the coagulation area is the portal venous flow. Occlusion of the hepatic artery alone does not significantly increase lesion size. T2w sequences are best suited for postprocedure imaging due to the high lesion-to-liver CNR in rabbits with normal hepatic perfusion. J. Magn. Reson. Imaging 2001;13:57-63.

Diagnosis of papillomas of the breast: value of magnetic resonance mammography in comparison with galactography.

The aim of this study was evaluation of MRI alone and in combination with mammography and galactography in the diagnosis of intraductal papillomas. From 1994 to 1998, a total of 48 women presenting with pathologic mammary secretion underwent galactography and magnetic resonance mammography (MRM). Thirty-five patients aged 16-71 years (average age 46 years) subsequently underwent surgery or diagnostic puncture and the histologic findings were compared with the results of the radiologic examination. Histology revealed papillomas in 16 cases. In 6 of these patients, there was associated malignant degeneration. Malignancy without associated papilloma was observed in 3 cases. Galactography displayed a sensitivity of 94% and a specificity of 79% with five false-positive findings and one false-negative finding in the recognition of intraductal papillomas. Malignant processes were detected by mammography/galactography in only one instance. Magnetic resonance mammography visualized pathologic contrast medium uptake in 8 of 9 cases of malignant disease (sensitivity 89%). One patient with in situ ductal carcinoma escaped detection with MRM. Papillomas showed no or below-the-threshold-lying contrast uptakes with no specific sign suggestive of papilloma. Galactography in combination with mammography remains the primary diagnostic procedure in cases of pathologic mammary secretion or suspected papilloma. The addition of MRI permits exclusion of malignant disease with a high degree of certainty; thus, expectant management in individual cases with negative findings appears justified.