[Vascular diagnostics in peripheral arteries]. / Gefäßdiagnostik an peripheren Arterien.

Peripheral artery disease (PAD) is the most frequent cause for reduced perfusion in peripheral arteries. Patients with PAD have often manifestations of atherosclerosis in other vascular territories. Typical symptoms are intermittent claudication or rest pain and acral lesions in patients with critical limb ischemia. The majority of PAD patients are clinically asymptomatic; therefore, it makes sense to screen for PAD in patients with cardiovascular risk factors. The ankle brachial index (ABI) is regarded as an easy and cost-effective method for baseline diagnostics. If ABI measurement confirms the suspected PAD, a detailed diagnostic pathway should follow in which duplex sonography plays a central role. In some cases, additional radiologic imaging preferably by magnet resonance imaging is necessary to complete the diagnostic workup or to plan therapeutic procedures.

Risk of cancer incidence before the age of 15 years after exposure to ionising radiation from computed tomography: results from a German cohort study.

The aim of this cohort study was to assess the risk of developing cancer, specifically leukaemia, tumours of the central nervous system and lymphoma, before the age of 15 years in children previously exposed to computed tomography (CT) in Germany. Data for children with at least one CT between 1980 and 2010 were abstracted from 20 hospitals. Cancer cases occurring between 1980 and 2010 were identified by stochastic linkage with the German Childhood Cancer Registry (GCCR). For all cases and a sample of non-cases, radiology reports were reviewed to assess the underlying medical conditions at time of the CT. Cases were only included if diagnosis occurred at least 2 years after the first CT and no signs of cancer were recorded in the radiology reports. Standardised incidence ratios (SIR) using incidence rates from the general population were estimated. The cohort included information on 71,073 CT examinations in 44,584 children contributing 161,407 person-years at risk with 46 cases initially identified through linkage with the GCCR. Seven cases had to be excluded due to signs possibly suggestive of cancer at the time of first CT. Overall, more cancer cases were observed (O) than expected (E), but this was mainly driven by unexpected and possibly biased results for lymphomas. For leukaemia, the SIR (SIR = O/E) was 1.72 (95 % CI 0.89-3.01, O = 12), and for CNS tumours, the SIR was 1.35 (95 % CI 0.54-2.78, O = 7). Despite careful examination of the medical information, confounding by indication or reverse causation cannot be ruled out completely and may explain parts of the excess. Furthermore, the CT exposure may have been underestimated as only data from the participating clinics were available. This should be taken into account when interpreting risk estimates.

The Urological Dyna-CT: ex vivo feasibility study of interventional cross-sectional imaging in the endourological operation room.

BACKGROUND: Imaging of the urinary tract and its surrounding tissue still remains challenging, since standard imaging in the urological operation room consists of fluoroscopy and plain X-rays. The combination of a ceiling-mounted X-ray system and a new urological intervention table now allows cross-sectional imaging and 3D reconstruction to be performed in the endourological operation room (Urological Dyna-CT). MATERIALS AND METHODS: The imaging quality of the Artis Zee Ceiling (Siemens Medical Solutions, Erlangen, Germany) was assessed using slice images of an ex vivo pig kidney model prepared with artificial stones (plaster of Paris). We compared the image quality of three different examination protocols with this model. 3D reconstruction quality was illustrated by means of retrograde filling of one pig`s urinary tract with a diluted contrast medium. RESULTS: Interventional stone detection and localization is possible with a 5 s low-dose Urological Dyna-CT. Detailed imaging of the collecting system by retrograde pyelography is possible with a high image quality. CONCLUSION: The combination of an Artis Zee(®) Ceiling (Siemens Medical Solutions, Erlangen, Germany) with our newly developed urological intervention table we call the Urological Dyna-CT. In addition to such standard procedures as fluoroscopy or plain X-rays, cross-sectional imaging and 3D reconstruction of the urinary tract are possible and provide fast and excellent urological imaging.

[Radiology and pregnancy : Part 2: clinical recommendations]. / Radiologie und Schwangerschaft : Teil 2: Klinische Empfehlungen.

In spite of a growing number of radiological scans in pregnant women there is still a high level of uncertainty concerning radiation exposure to the fetus. At the same time, the risk of fetal radiation injury is frequently overestimated. This entails an avoidable fear in the pregnant patient and may delay urgently required imaging and thus lead to an increased risk for maternal and fetal health. As a consequence, radiological scans in pregnant patients do not only require a thorough medical check but also a careful estimate of the specific radiation exposure to the fetus. The previous first part of the article described the legal requirements in Germany, the technical exposure and pharmacological risks for the pregnant woman and the fetus. The current second article focuses on the risk analysis for examinations with ionizing radiation and will provide recommendations for typical indications for maternal and fetal imaging.

[The urological Dyna-CT. Urological cross-sectional imaging on a newly developed urological intervention table]. / Das urologische Dyna-CT. Urologische Schnittbildgebung auf einem neu entwickelten urologischen Interventionstisch.

BACKGROUND: The development of a new urological intervention table now enables the application of an Artis zee ceiling Dyna-CT (Siemens, Erlangen, Germany) for interventional cross-sectional imaging and 3-D reconstruction of the urinary tract in the prone and supine positions (urological Dyna-CT). MATERIALS AND METHODS: We tested the feasibility of the urological Dyna-CT with the newly developed urological intervention table. The system was moved five times to enable 3-D reconstruction of the urinary tract of a test person in the prone and in supine positions. RESULTS: Handling of the free floating table is easily possible during the intervention. We found no limitation of imaging system movement in any position of the test person. CONCLUSION: Apart from standard urological imaging such as fluoroscopy, intravenous pyelography or plain abdominal X-ray the urological Dyna-CT enables further imaging of the urinary tract. Fluoroscopy sequences can be stored as videos, and 3-D reconstructions of the urinary tract are possible with permanent patient access for any intervention. Extensive tests led to the technical approval of the system in urology.

[Current requirements for image management in radiotherapy]. / Aktuelle Anforderungen an das Bildmanagement in der Strahlentherapie.

AIMS AND METHODS: Treatment techniques of increasing complexity such as dynamic/rotational techniques mandate digital management and increasingly image guidance. This constantly increases requirements for image management and archiving. This article discusses the current status of these requirements and will present potential image administration strategies. RESULTS: Fundamentals of image administration and storage/archiving are presented (DICOM Standard, radiotherapy-specific issues) along the typical patient pathway (demographic data, radiotherapy treatment planning, signatures/approval of plan and image data, archiving of plan and image data). Different strategies for image management are presented (archiving centered on individual application vs. integral approach with central archiving in a DICOM-RT-PACS governed by a radiation oncology information system (ROCIS)). Infrastructural requirements depending on the amount of image data generated in the department are discussed. CONCLUSION: Application-centered image management provides access to image data including all relevant RT-specific elements. This approach, however, is not migration-safe, requires significant administrative work to ensure a redundancy level that protects against data loss and does not provide datasets that are linked to respective therapeutic interventions. Therefore, centralized image management and archiving that links images to patients and individual steps in the treatment pathway within a standardized DICOM(-RT) environment is preferable despite occasional problems with visualization of specific data elements.

[Radiology and pregnancy. Principles, general requirements and exposure]. / Radiologie und Schwangerschaft. Grundlagen, Rahmenbedingungen und Belastungen.

In a radiology department there are frequently asked questions associated with pregnant and breast feeding women. These are related to either pregnant patients or staff members or the questions are centered on the fetus as a patient. For pregnant patients the potential exposure to the mother and the fetus related to the imaging modality selected as well as the effects of the necessary contrast media must be taken into account. Even for methods without ionizing radiation possible limitations in the use for pregnant women must be discussed. Finally, this medical check defines the imaging modality and the necessary protocol and contrast media. The present article describes the legal requirements in Germany, the technical exposure and pharmacological risks for the pregnant woman and the fetus regarding imaging modalities with and without ionizing radiation. The forthcoming second article will address the risk analysis for examinations with ionizing radiation and will present recommendations for typical clinical imaging problems.

Process analysis to reduce MRI access time at a German University Hospital.

QUALITY PROBLEM OR ISSUE: Long access times for magnetic resonance imaging (MRI) can negatively impact the quality of care provided to patients. We investigated improving access by reducing MRI processing time. INITIAL ASSESSMENT: Data were collected for scans (n= 360) performed over 3 weeks (April-May 2008) at the University Hospital of Mannheim, Germany. Average access time, excluding emergencies, was 44 (±44) days for outpatients and 3 (±5) days for inpatients. Factors influencing total MRI processing time were identified using multivariate linear regression. In addition to region scanned, the total MRI processing time was significantly related to performing multiple scans (ß = 33.57, P< 0.01), using oral contrast media (ß = 13.58, P< 0.01), placing an intravenous (IV) catheter (ß = 5.00, P= 0.04) and scanning patients ≤8 years old (ß = 0.41, P= 0.03). Contrary to prior perceptions, emergency cases (5.6%) and late arrivals (12.8% >5 min late) were less than expected. CHOICE OF SOLUTION: Increasing scheduling flexibility to address non-modifiable process variation and completing preparatory activities outside the scanner room were identified as process improvement targets. IMPLEMENTATION: Scheduling was adapted to utilize three expected total MRI processing times and IV placement was moved outside the scanner room. EVALUATION: Planned hardware and software upgrades were completed concurrent to the process improvements. As a result, it was not possible to accurately measure the effect of implementing the scheduling and preparatory activity changes. LESSONS LEARNED: Clinical study team members' prior perceptions of workflow obstacles did not match the study findings. Utilizing insiders and outsiders during process analysis may limit bias in identification of process improvement opportunities.

[New oral anticoagulants for treatment of venous thromboembolism]. / Neue orale Antikoagulanzien zur Therapie der venösen Thromboembolie.

In the current treatment of venous thromboembolism most patients are treated with vitamin K antagonists (VKA). VKA have many disadvantages including slow onset of action, multiple food and drug interactions and a large inter-individual variability in their efficacy. Recently several alternative oral anticoagulants have been developed, which have several advantages in comparison to VKA. So far two large randomized studies comparing new oral anticoagulants with VKA in patients with venous thromboembolism have been published: the RECOVER study with the oral direct thrombin antagonist dabigatran and the EINSTEIN-DVT study with the oral direct factor Xa-antagonist rivaroxaban. With regard to recurrent venous thromboembolism and bleeding complications, both drugs were comparable with VKA. In addition, two other studies are ongoing with the oral direct factor Xa antagonists apixaban and edoxaban for this indication. The final role of the new oral anticoagulants in the future treatment of venous thromboembolism has to be determined. However the first results from randomized trails are encouraging.

Computed tomography in children: multicenter cohort study design for the evaluation of cancer risk.

Exposure to ionizing radiation is a known risk factor for cancer. Cancer risk is highest after exposure in childhood. The computed tomography is the major contributor to the average, individual radiation exposure. Until now the association has been addressed only in statistical modeling. We present the first feasible study design on childhood cancer risk after exposure to computed tomography.

[Basics of German teleradiology]. / Grundlagen der Teleradiologie.

The methods and techniques of teleradiology are used in numerous clinical specialties. Several teleradiology projects have been state-aided in Germany over the last 10 years. Using the teleradiology standard proposed by the German Radiology Society, some of these systems are also interoperable. Several techniques are available for realizing teleradiology connections, including Web servers, virtual private networks (VPNs), and e-mail-based solutions. For the establishment of a new teleradiology connection, the needed applications must be analysed in order to find an adequate and cost-effective solution. Legal, financial, and data security aspects must also be taken into account. Legal regulations for the use of teleradiology-guided examinations in Germany demand a high technical and organisational standard for the set-up and the quality control of teleradiology installations.

Teleradiology applications with DICOM-e-mail.

For the connection of several partners to a Dicom-e-mail based teleradiology network concepts were developed to allow the integration of different teleradiology applications. The organisational and technical needs for such an integration were analysed. More than 60 institutions including 23 hospitals in the Rhein-Neckar-Region, Germany were connected. The needed functionality was grouped in six teleradiology applications (emergency consultation, tele-guided examinations, expert consultations, cooperative work, scientific cooperations and homework with on call services) and their technical and organisational needs according to availability, speed of transfer, workflow definitions and data security needs was analysed. For the local integration of teleradiology services the setup and workflow is presented for a standalone teleradiology workstation and a server based teleradiology gateway. The line type needed for different groups of applications and users is defined. The security concept and fallback strategies are laid out, potential security problems and sources of errors are discussed. The specialties for the emergency teleradiology application are presented. The DICOM-e-mail protocol is a flexible and powerful protocol that can be used for a variety of teleradiology applications. It can meet the conditions for emergency applications but is limited if synchronous applications like teleconferences are needed.

Standardization of teleradiology using Dicom e-mail: recommendations of the German Radiology Society.

Until recently there has been no standard for an interoperable and manufacturer-independent protocol for secure teleradiology connections. This was one of the main reasons for the limited use of teleradiology in Germany. Various teleradiology solutions have been developed in the past, but the vast majority have not been interoperable. Therefore an ad hoc teleradiology connection was impossible even between partners who were already equipped with teleradiology workstations. Based on the evaluation of vendor-independent protocols in recent years the IT Working Group (AGIT) of the German Radiology Society set up an initiative to standardize basic teleradiology. An e-mail based solution using the Dicom standard for e-mail attachments with additional encryption according to the OpenPGP standard was found to be the common denominator. This protocol is easy to implement and safe for personalized patient data and fulfills the legal requirements for teleradiology in Germany and other countries. The first version of the recommendation was presented at the 85th German Radiology Convention in 2004. Eight commercial and three open-source implementations of the protocol are currently available; the protocol is in daily use in over 50 hospitals and institutions.

[Teleradiology with DICOM e-mail: recommendations of @GIT]. / Teleradiologie mit DICOM E-mail: Empfehlungen der @GIT.

E-mail is ideal for ad-hoc connections in teleradiology. The DICOM standard offers the possibility to append DICOM data types as a MIME attachment to any e-mail, thus ensuring the transmission of the original DICOM data. Nevertheless, there are additional requirements (e.g. protection of data privacy) which must be obeyed. Because of the lack of given standards which would grant interoperability as well as manufacturer independence, teleradiology has not been established in Germany until today. Therefore, the IT-Team (Arbeitsgemeinschaft fur Informationstechnologie, @GIT) of the Radiological Society of Germany (Deutsche Rontgengesellschaft, DRG) set up an initiative to standardise telemedicine by using e-mail. Its members agreed that an e-mail-based variant would be the most practicable way to a communication solution -- as easy to implement as to use. In their opinion, e-mail represents the smallest common denominator for a safe data interchange that would fulfill the legal advantages for telemedicine in Germany.

[Value of electron beam tomography (EBT)]. / Wertigkeit der Elektronenstrahl-Computertomographie (EBT) -- II. Nichtkardiale Anwendungen und Strahlenexposition.

Electron beam tomography (EBT) has been scientifically evaluated to a much lesser degree for non-cardiac indications than for cardiac purposes. Therefore, four groups of investigators in Berlin (2), Mannheim and Munchen, which were supported by the Deutsche Forschungsgemeinschaft (DFG), included applications outside the heart in their evaluation of EBT technology. EBT has proven useful to look for pulmonary embolism and to assess other vessels (aorta, aortic branches, and intracranial arteries). Imaging of the lung parenchyma benefits from its intrinsic high contrast and from the fast data acquisition of EBT. Limited photon efficiency, higher radiation exposure, increased noise levels and other artifacts, however, markedly reduce the value of EBT for imaging of low contrast objects compared to conventional spiral CT and multislice CT (MSCT), compromising, in particular, the morphologic depiction of parenchymal abdominal organs and the brain. Consequently, scientific studies to further evaluate EBT for scanning of the brain and parenchymal abdominal organs were not pursued. Radiation exposure for non-cardiac EBT studies is up to three times higher than that for respective spiral CT studies, and in children EBT can only be advocated in select cases. Radiation exposure for the various prospectively triggered cardiac examination protocols of EBT is lower than that for conventional coronary angiography. Radiation exposure in cardiac multislice CT exceeds severalfold that of EBT, but the dose efficiency of EBT and MSCT are similar due to higher spatial resolution and less image noise of MSCT. In addition, modifications of MSCT (ECG pulsing) can further reduce radiation exposure to the level of EBT. Technical improvements of the EBT successor scanner "e-Speed" enable faster data acquisition at higher spatial resolution. Within comparative studies, the "e-Speed" will have to prove its value and competitiveness, particularly in comparison with multislice CT. After profound scientific assessment in a multicenter evaluation supported by the Deutsche Forschungsgemeinschaft (DFG) and regardless of the specific suitability of electron beam tomography for various cardiac and some non-cardiac indications, the investigators unanimously find the electron beam tomograph Evolution C150 XP not suitable as a whole body CT scanner.

[Diagnostic value of electron-beam computed tomography (EBT). I. Cardiac applications]. / Diagnostische Wertigkeit der Elektronenstrahl-Computertomographie (EBT). I. Kardiale Anwendungen.

Electron beam tomography (EBT) directly competes with other non-invasive imaging modalities, such as multislice computed tomography, magnetic resonance imaging, and echocardiography, in the diagnostic assessment of cardiac diseases. EBT is the gold standard for the detection and quantification of coronary calcium as a preclinical sign of coronary artery disease (CAD). Its standardized examination protocols and the broad experience with this method favor EBT. First results with multislice CT indicate that this new technology may be equivalent to EBT for coronary calcium studies. The principal value of CT-based coronary calcium measurements continues to be an issue of controversy amongst radiologists and cardiologists due to lack of prospective randomized trials. Coronary angiography with EBT is characterized by a high negative predictive value and, in addition, may be indicated in some patients with manifest CAD. It remains to be shown whether coronary angiography with multislice CT is reliable and accurate enough to be introduced into the routine work-up, to replace some of the many strictly diagnostic coronary catheterizations in Germany and elsewhere. Assessment of coronary stent patency with EBT is associated with several problems and in our opinion cannot be advocated as a routine procedure. EBT may be recommended for the evaluation of coronary bypasses to look for bypass occlusions and significant stenoses, which, however, can be equally well achieved with multislice CT. Quantification of myocardial perfusion with EBT could not replace MRI or other modalities in this field. EBT has proven to be accurate, reliable and in some instances equivalent to MRI, which is the gold standard for the quantitative and qualitative evaluation of cardiac function. Some disadvantages, not the least of which is the limited distribution of electron beam scanners, favor MRI for functional assessment of the heart.

Effects of end-inspiratory and end-expiratory pressures on alveolar recruitment and derecruitment in saline-washout-induced lung injury -- a computed tomography study.

BACKGROUND: Lung protective ventilation using low end-inspiratory pressures and tidal volumes (VT) has been shown to impair alveolar recruitment and to promote derecruitment in acute lung injury. The aim of the present study was to compare the effects of two different end-inspiratory pressure levels on alveolar recruitment, alveolar derecruitment and potential overdistention at incremental levels of positive end-expiratory pressure. METHODS: Sixteen adult sheep were randomized to be ventilated with a peak inspiratory pressure of either 35 cm H2O (P35, low VT) or 45 cm H2O (P45, high VT) after saline washout-induced lung injury. Positive end-expiratory pressure (PEEP) was increased in a stepwise manner from zero (ZEEP) to 7, 14 and 21 cm of H2O in hourly intervals. Tidal volume, initially set to 12 ml kg(-1), was reduced according to the pressure limits. Computed tomographic scans during end-expiratory and end-inspiratory hold were performed along with hemodynamic and respiratory measurements at each level of PEEP. RESULTS: Tidal volumes for the two groups (P35/P45) were: 7.7 +/- 0.9/11.2 +/- 1.3 ml kg(-1) (ZEEP), 7.9 +/- 2.1/11.3 +/- 1.3 ml kg(-1) (PEEP 7 cm H2O), 8.3 +/- 2.5/11.6 +/- 1.4 ml kg(-1) (PEEP 14 cm H2O) and 6.5 +/- 1.7/11.0 +/- 1.6 ml kg(-1) (PEEP 21 cm H2O); P < 0.001 for differences between the two groups. Absolute nonaerated lung volumes during end-expiration and end-inspiration showed no difference between the two groups for given levels of PEEP, while tidal-induced changes in nonaerated lung volume (termed cyclic alveolar instability, CAI) were larger in the P45 group at low levels of PEEP. The decrease in nonaerated lung volume was significant for PEEP 14 and 21 cm H2O in both groups compared with ZEEP (P < 0.005). Over-inflated lung volumes, although small, were significantly higher in the P45 group. Significant respiratory acidosis was noted in the P35 group despite increases in the respiratory rate. CONCLUSION: Limiting peak inspiratory pressure and VT does not impair alveolar recruitment or promote derecruitment when using sufficient levels of PEEP.

[New concepts in teleradiology with Dicom e-mail]. / Neue Konzepte in der Teleradiologie mit Dicom-e-mail.

UNLABELLED: The recently published Dicom supplement 54 (dicom e-mail) defines a connection between the internet and the medical communication inside hospitals. Up to now vendor specific dicom protocol additions were needed to realize certain teleradiology solutions. The new concept relies on vendor independent standard protocols without specific additions. MAIN FEATURES: client-server solution using the internet designed for emergency medicine integration of various clinical informations approved security concept modularized architecture The concept was realized within the scope of a teleradiology project of the state of Rheinland-Pfalz, Germany. It will be expanded to the state of Baden-Wuerttemberg. Germany in 2002 with over 20 hospitals included.