Notifications and alerts in patient dose values for computed tomography and fluoroscopy-guided interventional procedures.

The terms "notifications" and "alerts" for medical exposures are used by several national and international organisations. Recommendations for CT scanners have been published by the American Association of Physicists in Medicine. Some interventional radiology societies as well as national authorities have also published dose notifications for fluoroscopy-guided interventional procedures. Notifications and alerts may also be useful for optimisation and to avoid unintended and accidental exposures. The main interest in using these values for high-dose procedures (CT and interventional) is to optimise imaging procedures, reducing the probability of stochastic effects and avoiding tissue reactions. Alerts in X-ray systems may be considered before procedures (as in CT), during procedures (in some interventional radiology systems), and after procedures, when the patient radiation dose results are known and processed. This review summarises the different uses of notifications and alerts to help in optimisation for CT and for fluoroscopy-guided interventional procedures as well as in the analysis of unintended and accidental medical exposures. The paper also includes cautions in setting the alert values and discusses the benefits of using patient dose management systems for the alerts, their registry and follow-up, and the differences between notifications, alerts, and trigger levels for individual procedures and the terms used for the collective approach, such as diagnostic reference levels. KEY POINTS: • Notifications and alerts on patient dose values for computed tomography (CT) and fluoroscopy-guided interventional procedures (FGIP) allow to improve radiation safety and contribute to the avoidance of radiation injuries and unintended and accidental exposures. • Alerts may be established before the imaging procedures (as in CT) or during and after the procedures as for FGIP. • Dose management systems should include notifications and alerts and their registry for the hospital quality programmes.

Dosimetric quantities and effective dose in medical imaging: a summary for medical doctors.

This review presents basic information on the dosimetric quantities used in medical imaging for reporting patient doses and establishing diagnostic reference levels. The proper use of the radiation protection quantity "effective dose" to compare doses delivered by different radiological procedures and different imaging modalities with its uncertainties and limitations, is summarised. The estimates of population doses required by the European Directive on Basic Safety Standards is commented on. Referrers and radiologists should be familiar with the dose quantities to inform patients about radiation risks and benefits. The application of effective dose on the cumulative doses from recurrent imaging procedures is also discussed. Patient summary: Basic information on the measurement units (dosimetric quantities) used in medical imaging for reporting radiation doses should be understandable to patients. The Working Group on "Dosimetry for imaging in clinical practice" recommended that a brief explanation on the used dosimetric quantities and units included in the examination imaging report, should be available for patients. The use of the quantity "effective dose" to compare doses to which patients are exposed to from different radiological procedures and its uncertainties and limitations, should also be explained in plain language. This is also relevant for the dialog on to the cumulative doses from recurrent imaging procedures. The paper summarises these concepts, including the need to estimate the population doses required by the European Directive on Basic Safety Standards. Referrers and radiologists should be familiar with the dose quantities to inform patients about radiation risks and benefits.

Statement of the German Roentgen Society, German Society of Neuroradiology, and Society of German-speaking Pediatric Radiologists on Requirements for the Performance and Reporting of MR Imaging Examinations Outside of Radiology. / Positionspapier der Deutschen Röntgengesellschaft (DRG), der Deutschen Gesellschaft für Neuroradiologie (DGNR) und der Gesellschaft für Pädiatrische Radiologie (GPR) zu den fachlichen Anforderungen an Durchführung und Befundung von MRT-Untersuchungen außerhalb des Fachgebietes Radiologie.

BACKGROUND: Magnetic Resonance Imaging (MRI) is a very innovative, but at the same time complex and technically demanding diagnostic method in radiology. It plays an increasing role in high-quality and efficient patient management. Quality assurance in MRI is of utmost importance to avoid patient risks due to errors before and during the examination and when reporting the results. Therefore, MRI requires higher physician qualification and expertise than any other diagnostic imaging technique in medicine. This holds true for indication, performance of the examination itself, and in particular for image evaluation and writing of the report. In Germany, the radiologist is the only specialist who is systematically educated in all aspects of MRI during medical specialty training and who must document a specified, high number of examinations during this training. However, also non-radiologist physicians are increasingly endeavoring to conduct and bill MRI examinations on their own. METHOD: In this position statement, the following aspects of quality assurance for MRI examinations and billing by radiologists and non-radiologist physician specialists are examined scientifically: Requirements for specialist physician training, MRI risks and contraindications, radiation protection in the case of non-ionizing radiation, application of MR contrast agents, requirements regarding image quality, significance of image artifacts and incidental findings, image evaluation and reporting, interdisciplinary communication and multiple-eyes principle, and impact on healthcare system costs. CONCLUSION: The German Roentgen Society, German Society of Neuroradiology, and Society of German-speaking Pediatric Radiologists are critical with regard to MRI performance by non-radiologists in the interest of quality standards, patient welfare, and healthcare payers. The 24-month additional qualification in MRI as defined by the physician specialization regulations (Weiterbildungsordnung) through the German state medical associations (Landesärztekammern) is the only competence-based and quality-assured training program for board-certified specialist physicians outside radiology. This has to be required as the minimum standard for performance and reporting of MRI exams. Exclusively unstructured MRI training outside the physician specialization regulations has to be strictly rejected for reasons of patient safety. The performance and reporting of MRI examinations must be reserved for adequately trained and continuously educated specialist physicians. KEY POINTS: · MR imaging plays an increasing role due to its high diagnostic value and serves as the reference standard in many indications.. · MRI is a complex technique that implies patient risks in case of inappropriare application or lack of expertise.. · In Germany, the radiologist is the only specialist physician that has been systematically trained in all aspects of MRI such as indication, performance, and reporting of examinations in specified, high numbers.. · The only competence-based and quality-assured MRI training program for specialist physicians outside radiology is the 24-month additional qualification as defined by the regulations through the German state medical associations.. · In view of quality-assurance and patient safety, a finalized training program following the physician specialization regulations has to be required for the performance and reporting of MRI examinations.. CITATION FORMAT: · Hunold P, Bucher AM, Sandstede J et al. Statement of the German Roentgen Society, German Society of Neuroradiology, and Society of German-speaking Pediatric Radiologists on Requirements for the Performance and Reporting of MR Imaging Examinations Outside of Radiology. Fortschr Röntgenstr 2021; 193: 1050 - 1060.

Cumulative effective dose from recurrent CT examinations in Europe: proposal for clinical guidance based on an ESR EuroSafe Imaging survey.

In recent years, the issue of cumulative effective dose received from recurrent computed tomography examinations has become a subject of increasing concern internationally. Evidence, predominantly from the USA, has shown that a significant number of patients receive a cumulative effective dose of 100 mSv or greater. To obtain a European perspective, EuroSafe Imaging carried out a survey to collect European data on cumulative radiation exposure of patients from recurrent computed tomography examinations. The survey found that a relatively low percentage of patients (0.5%) received a cumulative effective dose equal to or higher than 100 mSv from computed tomography, most of them having an oncological disease. However, there is considerable variation between institutions as these values ranged from 0 to 2.72%, highlighting that local practice or, depending on the institution and its medical focus, local patient conditions are likely to be a significant factor in the levels of cumulative effective dose received, rather than this simply being a global phenomenon. This paper also provides some practical actions to support the management of cumulative effective dose and to refine or improve practice where recurrent examinations are required. These actions are focused around increasing awareness of referring physicians through encouraging local dialogue, actions focused on optimisation where a team approach is critical, better use of modern equipment and the use of Dose Management and Clinical Decision Support Systems together with focused clinical audits. The proper use of cumulative effective dose should be part of training programmes for referrers and practitioners, including what information to give to patients. Radiation is used to the benefit of patients in diagnostic procedures such as CT examinations, and in therapeutic procedures like the external radiation treatment for cancer. However, radiation is also known to increase the risk of cancer. To oversee this risk, the cumulative effective dose (CED) received by a patient from imaging procedures over his or her life is important. In this paper, the authors, on behalf of EuroSafe Imaging, report on a survey carried out in Europe that aims to estimate the proportion of patients that undergo CT examinations and are exposed to a CED of more than 100 mSv. At the same time, the survey enquires about and underlines radiologists' measures and radiology departments' strategies to limit such exposure. Over the period of 2015-2018, respondents reported that 0.5% (0-2.72%) of patients were exposed to a CED of ≥ 100 mSv from imaging procedures. The background radiation dose in Europe depends on the location, but it is around 2.5 mSv per year. It is obvious that patients with cancer, chronic diseases and trauma run the highest risk of having a high CED. However, even if the number of patients exposed to ≥ 100 mSv is relatively low, it is important to lower this number even further. Measures could consist in using procedures that do not necessitate radiation, using very low dose procedures, being very critical in requiring imaging procedures and increasing awareness about the issue. KEY POINTS: • A relatively low percentage of patients (0.5%) received a cumulative effective dose from CT computed tomography equal to or greater than 100 mSv, in Europe, most of them having an oncological disease. • There is a wide range in the number of patients who receive cumulative effective dose equal to or greater than 100 mSv (0-2.72%) and optimisation should be improved. • Increasing the awareness of referring physicians through encouraging local dialogue, concrete actions focused on optimisation and development of dose management systems is suggested.

How to Measure/Calculate Radiation Dose in Patients?

Patients in fluoroscopically guided interventions (FGI) may be exposed to substantial radiation dose levels (SRDL). The most commonly reported adverse reactions are skin injuries with erythema or necrosis. It is therefore important for the interventional radiologist to know deterministic effects with their threshold doses. If possible all relevant modality parameters should be displayed on the interventionalists screen. Dosimetric parameters should be displayed in digital imaging and communications in medicine (DICOM) units and stored as DICOM Radiation Dose Structured Report (RDSR). The peak skin dose (PSD) is the most relevant risk parameter for skin injuries. Dose management systems (DMS) help optimising radiation exposure of patients. However, their calculation of skin dose maps is only available after a FGI. Therefore, dose maps and PSD should preferably be calculated and displayed in real time by the modality.

ESR EuroSafe Imaging and its role in promoting radiation protection - 6 years of success.

This article introduces the European Society of Radiology's EuroSafe Imaging initiative in the year of its 6th anniversary. The European and global radiation protection frameworks are outlined and the role of the EuroSafe Imaging initiative's Call for Action in successfully achieving international radiation protection goals as set out by those frameworks is detailed.

Radiation dose management systems-requirements and recommendations for users from the ESR EuroSafe Imaging initiative.

The European Directive 2013/59/Euratom requires member states of the European Union to ensure justification and optimisation of radiological procedures and store information on patient exposure for analysis and quality assurance. The EuroSafe Imaging campaign of the European Society of Radiology created a working group (WG) on "Dose Management" with the aim to provide European recommendations on the implementation of dose management systems (DMS) in clinical practice. The WG follows Action 4: "Promote dose management systems to establish local, national, and European diagnostic reference levels (DRL)" of the EuroSafe Imaging Call for Action 2018. DMS are designed for medical practitioners, radiographers, medical physics experts (MPE) and other health professionals involved in imaging to support their tasks and duties of radiation protection in accordance with local and national requirements. The WG analysed requirements and critical points when installing a DMS and classified the individual functions at different performance levels. KEY POINTS: • DMS are very helpful software tools for monitoring patient exposure, optimisation, compliance with DRLs and quality assurance. • DMS can help to fulfil dosimetric aspects of the European Directive 2013/59/Euratom. • The EuroSafe WG analyses DMS requirements and gives recommendations for users.

The new radiation protection framework since 2019 - Implementation in Germany and comparison of some aspects in seven European countries. / Das neue Strahlenschutzrecht ab 2019 ­ Umsetzung in Deutschland und Vergleich einzelner Aspekte in 7 europäischen Ländern.

PURPOSE: The implementation of EU Directive 2013/59 EURATOM (EU-BSS) of 2014 led to a reorganization of radiation protection legislation in Germany in the form of a new radiation protection law Strahlenschutzgesetz (StrlSchG) of 2017 and a new radiation protection ordinance Strahlenschutzverordnung (StrlSchV) of 2018. For application of ionizing radiation in medicine these changes affect radiology, nuclear medicine and radiotherapy. A comparison between the old and the new legal system analyses changes that are relevant for diagnostic and interventional radiology. For the important new regulation of unintended exposures, a comparison is made with the implementation of Art. 63 EU-BSS in 7 European countries. MATERIAL AND METHODS: The provisions of the Röntgenverordnung (RöV) and the old Strahlenschutzverordnung (StrlSchV alt), which were valid until 2018, are compared with the new legislation of StrlSchG and StrlSchV for changes in radiation protection for patients, the population and occupational radiation protection of staff members. The occupational dose limit of the eye lens was reduced. The reduction by a factor of 7.5 results in new requirements for radiation protection equipment. New requirements in teleradiology are compared with the previous regulation, as well as the necessary involvement of medical physics experts (MPE) in high dose procedures, such as CT and fluoroscopic interventions. The regulation for unintended exposures of the German StrlSchV are analyzed in terms of their reporting criteria. RESULTS: The principles of medical radiation protection in Germany have not changed as a result of the new radiation protection legislation from 2019 onwards. However, there are a number of changes and new requirements that must be considered and implemented. Important points are e. g. new regulations on teleradiology, early detection of diseases in asymptomatic individuals and reporting of unintended exposure of patients. As all new regulations are no longer found in only one single regulation, both knowledge of the StrlSchG and the StrlSchV are necessary. KEY POINTS: · The EU Directive 2013/59 EURATOM (EU-BSS) was transposed into the new German radiation protection law 2018. · The basic regulations of the RöV and old StrlSchV remain unchanged. · Newly added regulations must be known and implemented in practice. · Many regulations of the EU-BSS are so vaguely formulated that they allow a wide scope for national implementation. CITATION FORMAT: · Loose R, Wucherer M, Walz M et al. The new radiation protection framework since 2019 - Implementation in Germany and comparison of some aspects in seven European countries. Fortschr Röntgenstr 2020; 192: 1036 - 1045.

Harmonisation of imaging dosimetry in clinical practice: practical approaches and guidance from the ESR EuroSafe Imaging initiative.

The European Directive 2013/59/EURATOM requires member states of the European Union to ensure justification and optimisation of the radiological procedures and to include information on patient exposure as part of the report of the examinations. The EuroSafe Imaging campaign of the European Society of Radiology created a working group (WG) on "Dosimetry for imaging in clinical practice" with the aim to help with the dosimetry aspects required by European and national regulations. The primary focus topics were selected and a survey among the experts of the WG, allowed suggesting some initial consensus approaches.For information on patient exposure, it was agreed to include the dosimetric values reported by the imaging modalities (validated by a medical physics expert). It was also suggested to prepare educational material on dosimetric quantities for patients. Individual optimisation was considered a challenge, especially for interventional procedures. In these cases, patient and occupational doses should be part of the global optimisation process and trigger levels should be defined to avoid skin radiation injuries. Diagnostic Reference Levels (DRLs) always need to be considered for comparison with periodic patient dose audits. In the case of accidental or unintended exposures, a report should be produced for the Quality Assurance programme, together with an educational note to avoid the repetition of incidents. Dose registry and management systems should allow fulfilling the regulatory requirements of national and European regulations. In a second step, and after the initial experience with the Directive implementation, a wider survey will be considered.

[What are the implications of the new radiation protection ordinance?] / Was bringt die neue Strahlenschutzverordnung?

The new regulatory basis in Germany for medical radiation protection ("Strahlenschutzverordnung" and "Strahlenschutzgesetz") went into effect on 31 December 2018 and has brought many changes. A system for record keeping and analysis of unintended exposures must be established and the occurrence of significant events must be reported to the competent authority. In the future, medical physics experts have to be consulted for equipment with high doses. Further programs for the early detection of diseases may be considered and approved by the federal office for radiation protection. Changes have been defined for teleradiology, procedure descriptions, tasks of the medical institutions for quality assurance and dose limits. Because of extended requirements for documentation and evaluations, the functionality of a dose management system will practically be necessary in bigger radiology departments or offices. Uncertainties in interpretation still exist for several parts of the regulations. The existing complementing guidelines shall be used for the time being.

Diagnostic Reference Levels for Diagnostic and Interventional X-Ray Procedures in Germany: Update and Handling. / Diagnostische Referenzwerte für diagnostische und interventionelle Röntgenanwendungen in Deutschland: Aktualisierung und Handhabung.

PURPOSE: Recent developments in medical technology have broadened the spectrum of X-ray procedures and changed exposure practice in X-ray facilities. For this reason, diagnostic reference levels (DRLs) for diagnostic and interventional X-ray procedures were updated in 2016 and 2018, respectively. It is the aim of this paper to present the procedure for the update of the DRLs and to give advice on their practical application. MATERIALS AND METHODS: For the determination of DRLs, data from different independent sources that collect dose-relevant data from different facilities in Germany were considered. Seven different weight intervals were specified for classifying pediatric X-ray procedures. For each X-ray procedure considered, the 25th, 50th, and 75th percentile of the respective national distribution of the dose-relevant parameters were determined. Additionally, effective doses that correspond to the DRLs were estimated. RESULTS: In procedures with already existing DRLs before 2016, the values were lowered by circa 20 % on average. Numerous DRLs were established for the first time (9 for interventional procedures, 10 for CT examinations). CONCLUSION: For dose optimizations even below the new national DRLs, the BfS recommends establishing local reference levels, using dose management software (particularly in CT and interventional radiology), adapting dose-relevant parameters of X-ray protocols to the individual patient size, and establishing internal radiation protection teams responsible for optimizing X-ray procedures in clinical practice. When applying good medical practice and using modern equipment, the median dose values of the nationwide dose distributions can not only be easily achieved but can even be undercut. KEY POINTS: · German diagnostic reference levels (DRLs) für diagnostic and interventional X-ray procedures were updated in 2016 and 2018, respectively.. · For X-ray procedures for which DRLs existed already before the update, the updated DLRs were lowered by circa 20 %, on average.. · For CT and interventional radiology, new DRLs were established.. · X-ray procedures have to be optimized even below the DRLs.. CITATION FORMAT: · Schegerer A, Loose R, Heuser LJ et al. Diagnostic Reference Levels for Diagnostic and Interventional X-Ray Procedures in Germany: Update and Handling. Fortschr Röntgenstr 2019; 191: 739 - 751.

Whole-Body CT in Multiple Trauma Patients: Clinically Adapted Usage of Differently Weighted CT Protocols. / Polytrauma-Ganzkörper-CT: Klinisch adaptierter Einsatz unterschiedlich gewichteter CT-Untersuchungsprotokolle.

PURPOSE: Whole-body CT (wbCT) has been established as an internationally accepted diagnostic modality in multiple trauma. Until 2011, a uniform CT scanning protocol was used for all multiple trauma patients (pat.) at our hospital (OLD protocol = OP). In 2011, 2 new differently weighted protocols were introduced: TIME protocol (TP) for hemodynamically unstable pat. and DOSE protocol (DP) for pat. with stable vital parameters. The aim of this study was to compare the original "One-fits-all-concept" with the new, clinically oriented approach to wbCT. MATERIALS AND METHODS: This study retrospectively evaluated 3 distinct wbCT protocols, looking at automatic exposure control variation (AEC; OP/TP) and arm positioning close to the body/overhead (TP/DP). The analysis included waist circumference (WC, cm), injury severity score (ISS), examination time (ET, min), image noise (IN), and effective dose (E, mSv). Normality of distribution was assessed with the Kolmogorov-Smirnov test. Data are given as median and range. Test of significance with Kruskal-Wallis test or Mann-Whitney-U-test. Level of significance: 0.05. RESULTS: 308 pat. were included in the study (77 % m; age: 46 a, 18 - 90 a; WC: 93 cm, 66 - 145 cm). ISS was 14 (OP; n = 104; 0 - 75), 18 (TP; n = 102; 0 - 75) and 9 (DP; n = 102; 0 - 50). ET was 3.9 min (OP; 3.3 - 5.6 min), 4.1 min (TP; 2.8 - 7.2 min) and 7.7 min (DP; 6 - 10 min). IN showed no significant differences when comparing OP/TP but was significantly reduced in DP. For a wbCT (vertex to ischium), E could be reduced from 49.7 mSv to 35.4 mSv by optimizing AEC (OP/TP). Through the overhead repositioning of the arms in DP, a further reduction to 28.2 mSv was achieved. CONCLUSION: AEC and arm repositioning have a crucial influence on image quality and dose. The presented clinical approach is superior to the original concept. KEY POINTS: · The use of 2 differently weighted wbCT protocols allows a more flexible approach to the patient's clinical presentation.. · The clinically adapted concept presented in this study allows trauma care centers to reduce the collective dose.. · Whole-body CT is leading to exposure to relevant radiation doses - further multicenter research is required.. CITATION FORMAT: · Reske SU, Braunschweig R, Reske AW et al. Whole-Body CT in Multiple Trauma Patients: Clinically Adapted Usage of Differently Weighted CT Protocols. Fortschr Röntgenstr 2018; 190: 1141 - 1151.

Stent Implantation for Superior Vena Cava Syndrome of Malignant Cause.

Purpose The purpose of this paper is the retrospective analysis of endovascular therapy for the treatment of superior vena cava syndrome (SVCS) of malignant cause. This study focuses on the effectiveness of the therapy regarding the duration of remission, symptom control and practicability. Materials and Methods From January 2003 to November 2012, therapeutic implantation of one or more stents was performed in 141 patients suffering from SVCS. The medical history was retrospectively researched using digitalized patient files. If those were incomplete, secondary research was conducted using the cancer registry of the General Hospital Nuremberg, the cancer registry of the tumor center at Friedrich-Alexander-University Erlangen-Nuremberg (FAU) or information given by physicians in private practice. This data was collected using Microsoft Office Excel® and statistically analyzed using IBM SPSS Statistics 22®. Results 168 stents were implanted in 141 patients (median age: 64.6 years; range: 36 - 84), 86 being male and 55 being female. In 121 patients, SVCS was caused by lung cancer (85.8 %), in 9 patients by mediastinal metastasis of an extrathoracic carcinoma (6.4 %), in 3 patients by mesothelioma of the pleura (2.1 %) and in 1 patient by Hodgkin's disease (0.7 %). There was no histological diagnosis in 7 cases (4.9 %). The primary intervention was successful in 138 patients (97.9 %). Immediate thrombosis in the stent occurred in the remaining 3 cases. Recurrence of SVCS was observed in 22 patients (15.6 %), including 5 early and 17 late occlusions. Stent dislocation or breakage was not observed. As expected, the survival after implantation was poor. The median survival was 101 days, and the median occlusion-free survival was 80 days. Conclusion The symptomatic therapy of SVCS with endovascular stents is effective and safe. Despite effective symptom control and a low rate of recurrence, the patients' prognosis is poor. Key Points: · Patients with SVCS of malignant cause have a poor prognosis.. · Lung cancer is the most common cause for SVCS.. · Endovascular therapy is safe and effective.. Citation Format · Büstgens FA, Loose R, Ficker JH et al. Stent Implantation for Superior Vena Cava Syndrome of Malignant Cause. Fortschr Röntgenstr 2017; 189: 423 - 430.

How complicated is complicated diverticulitis?--phlegmonous diverticulitis revisited.

PURPOSE: The purpose of this study is to elucidate the accuracy of a clinical classification system for acute diverticulitis with special regard to "phlegmonous diverticulitis". METHODS: A consecutive patient series (n = 318; General Hospital Nuremberg, 1/2004-12/2006) was classified preoperatively (imaging with 4/16-slice spiral CT scanner) according to the Hansen and Stock (H&S) classification which is commonly used in Germany and evaluated based on histopathology. RESULTS: Pre-treatment classification grouped 30 patients (9.4%) as uncomplicated diverticulitis (type I according to H&S), for whom treatment was merely conservative. One hundred twelve patients (35.2%) were classified as phlegmonous diverticulitis (type IIA), 84 (26.4%) as "covered perforations" (type IIB) and 27 (8.5%) as "free perforations" (type IIC), and 54 (17.0%) as chronically recurrent diverticulitis (type III, 17.0%). The remaining 11 patients (3.5%) were not staged preoperatively. Accuracy of staging of complicated diverticulitis differed significantly between type IIC (100.0%), type IIB (91.0%), and type IIA (36.1%). The latter group was frequently understaged as it concealed a substantial number of patients (n = 44; 53.0%) with IIB disease. Neither laboratory tests (CRP/WBC) nor clinical parameters allowed distinction of correctly and falsely staged patients with type IIA disease. CONCLUSIONS: Patients with phlegmonous diverticulitis (type IIA) represent the most challenging group among patients with acute diverticulitis as they are frequently understaged and conceal cases with covered perforations (type IIB). This may support the view to subsume phlegmonous diverticulitis (type IIA) under complicated diverticulitis.

Enhancing transjugular intrahepatic portosystemic shunt puncture by using three-dimensional path planning based on the back projection of two two-dimensional portographs.

The purpose of this study was to prevent transjugular intrahepatic portosystemic shunt (TIPS) puncture failure by using three-dimensional (3D) path planning. This study was approved by the institutional review board; informed consent was obtained for the TIPS procedure. In four patients, a 3D path was planned from two two-dimensional (2D) CO2 portograms obtained at projections of 0 degrees and right anterior oblique 30 degrees . This path was overlaid onto the live fluoroscopy to guide the puncture image. In three of four patients, the target vessel was entered in the first attempt. In one patient with portal vein (PV) stenosis, the PV was entered with the third pass. This method has high potential to improve safety of the procedure and to reduce intervention time.

Comparison of 1.0 M gadobutrol and 0.5 M gadopentate dimeglumine-enhanced MRI in 471 patients with known or suspected renal lesions: results of a multicenter, single-blind, interindividual, randomized clinical phase III trial.

The purpose of this phase III clinical trial was to compare two different extracellular contrast agents, 1.0 M gadobutrol and 0.5 M gadopentate dimeglumine, for magnetic resonance imaging (MRI) in patients with known or suspected focal renal lesions. Using a multicenter, single-blind, interindividual, randomized study design, both contrast agents were compared in a total of 471 patients regarding their diagnostic accuracy, sensitivity, and specificity to correctly classify focal lesions of the kidney. To test for noninferiority the diagnostic accuracy rates for both contrast agents were compared with CT results based on a blinded reading. The average diagnostic accuracy across the three blinded readers ('average reader') was 83.7% for gadobutrol and 87.3% for gadopentate dimeglumine. The increase in accuracy from precontrast to combined precontrast and postcontrast MRI was 8.0% for gadobutrol and 6.9% for gadopentate dimeglumine. Sensitivity of the average reader was 85.2% for gadobutrol and 88.7% for gadopentate dimeglumine. Specificity of the average reader was 82.1% for gadobutrol and 86.1% for gadopentate dimeglumine. In conclusion, this study documents evidence for the noninferiority of a single i.v. bolus injection of 1.0 M gadobutrol compared with 0.5 M gadopentate dimeglumine in the diagnostic assessment of renal lesions with CE-MRI.