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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.

In congenital diaphragmatic hernia (CDH), lung hypoplasia and secondary pulmonary hypertension are the major causes of death and severe disability. Based on new therapeutic strategies survival rates could be improved to up to 80%. However, after surgical repair of CDH, long-term follow-up of these pediatric patients is necessary. In this, dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) provides insights into the pulmonary microcirculation and might become a tool within the routine follow-up program of CDH patients. However, whole lung segmentation from DCE-MRI scans is tedious and automated procedures are warranted. Therefore, in this study, an approach to semi-automated lung segmentation is presented. Segmentation of the lung is obtained by calculating the cross correlation and the area under curve between all voxels in the data set and a reference region-of-interest (ROI), here the arterial input function (AIF). By applying an upper and lower threshold to the obtained maps and intersecting these, a final segmentation is reached. This approach was tested on twelve DCE-MRI data sets of 2-year old children after CDH repair. Segmentation accuracy was evaluated by comparing obtained automatic segmentations to manual delineations using the Dice overlap measure. Optimal thresholds for the cross correlation were 0.5/0.95 and 0.1/0.5 for the area under curve, respectively. The ipsilateral (left) lung showed reduced segmentation accuracy compared to the contralateral (right) lung. Average processing time was about 1.4s per data set. Average Dice score was 0.7±0.1 for the whole lung. In conclusion, initial results are promising. By our approach, whole lung segmentation is possible and a rapid evaluation of whole lung perfusion becomes possible. This might allow for a more detailed analysis of lung hypoplasia of children after CDH.

Recent technical developments have facilitated the application of cone-beam computed tomography (CBCT) for interventional and intraoperative imaging. The aim of this study was to compare the radiation doses and image quality in CBCT with those of conventional multislice spiral computed tomography (MSCT) for abdominal and genitourinary imaging.Different CBCT and MSCT protocols for imaging soft tissues and hard-contrast objects at different dose levels were investigated in this study. Local skin and organ doses were measured with thermoluminescent dosimeters placed in an anthropomorphic phantom. Moreover, the contrast-to-noise ratio, the noise-power spectrum, and the high-contrast resolution derived from the modulation transfer function were determined in a phantom with the same absorption properties as those of anthropomorphic phantom.The effective dose of the examined abdominal/genitourinary CBCT protocols ranged between 0.35 mSv and 18.1 mSv. As compared with MSCT, the local skin dose of CBCT examinations could locally reach much higher doses up to 190 mGy. The effective dose necessary to realize the same contrast-to-noise ratio with CBCT and MSCT depended on the MSCT convolution kernel: the MSCT dose was smaller than the corresponding CBCT dose for a soft kernel but higher than that for a hard kernel. The noise-power spectrum of the CBCT images at tube voltages of 85/90 kV(p) is at least half of that of images measured at 103/115 kV(p) at any arbitrarily chosen spatial frequency. Although the pixel size and slice thickness of CBCT were half of those of the MSCT images, high-contrast resolution was inferior to the MSCT images reconstructed with a hard convolution kernel.As compared with MSCT using a medium-hard convolution kernel, CBCT produces images at medium noise levels and, simultaneously, medium spatial resolution at approximately the same dose. It is well suited for visualizing hard-contrast objects in the abdomen with relatively low image noise and patient dose. For the detection of low-contrast objects at standard tube voltages of approximately 120 kV(p), however, MSCT should be preferred.

Trotz einer wachsenden Zahl radiologischer Untersuchungen von Schwangeren bestehen oft Unsicherheiten uber die Gefahrdung des Feten durch eine begleitende Strahlenexposition. Dabei wird das Risiko fetaler Schaden haufig uberschatzt. Neben einer unnotigen Verunsicherung der Schwangeren kann die Verzogerung einer erforderlichen Bildgebung zu einer Gefahrdung des mutterlichen und fetalen Gesundheitszustands fuhren. Vor jeder radiologischen Untersuchung einer schwangeren Patientin ist daher nicht nur die Indikation kritisch zu uberprufen, sondern auch eine Nutzen-Risiko-Abwagung unter Berucksichtigung des tatsachlich zu erwartenden Risikos fur den Feten durchzufuhren. Im ersten Teil des Artikels wurden die gesetzlichen Rahmenbedingungen sowie die technischen und pharmakologischen Belastungen fur die Schwangere und den Fetus bei radiologischen Methoden behandelt. Im vorliegenden zweiten Teil wird auf die individuelle Risikoanalyse fur Untersuchungen mit ionisierenden Strahlen eingegangen, und es werden klinische Empfehlungen zu typischen Fragestellungen mutterlicher und fetaler Erkrankungen gegeben.

The aim was to investigate changes in the tumor bed on magnetic resonance mammography (MRM) after intraoperative radiotherapy (IORT) and whether they would limit the diagnostic value of posttherapeutic MRM. We retrospectively investigated 36 patients undergoing MRM after IORT (median interval 2.8 years, range 0.4–7.1). Wound cavities with fat necrosis were common after IORT (81%). They were associated with persisting contrast enhancement, i.e., enhancement was mostly seen irrespective of the posttherapeutic interval. It normally presented as rim enhancement and did not cause any diagnostic uncertainty if viewed together with other tissue characteristics. We do not expect a limited diagnostic value of MRM after IORT.

Immer komplexere Bestrahlungstechniken wie z. B. dynamische Techniken sind nur noch digital und bildgesteuert sinnvoll einsetzbar. Dadurch erhohen sich standig die Anforderungen an die Bilddokumentation und -archivierung. Diese Arbeit soll detailliert die aktuellen Anforderungen an das Bildmanagement in der Radioonkologie und mogliche Bildadministrationsstrategien darstellen. Es werden die Grundlagen der Bildspeicherung und -administration (DICOM-Standard, Besonderheiten in der Strahlentherapie) entlang des typischen Patientenpfads beschrieben (demografische Daten, Bestrahlungsplanung, Signatur/Approval und Archivierung von Plan- und Bildinformationen). Verschiedene Strategien des Bildmanagements werden konzeptionell gegenubergestellt (applikationsbezogene Bildarchivierung vs. integraler Ansatz mit zentraler Datenspeicherung in einem DICOM-RT-fahigen PACS unter Steuerung eines Radioonkologie-Informationssystems (ROKIS)). Anforderungen an die Infrastruktur (Speicherbedarf abhangig vom Bildaufkommen etc.) werden diskutiert. Applikationsbezogenes Bildmanagement ermoglicht gegenwartig jeweils unmittelbar den vollumfanglichen Zugriff auf Bilddaten einschlieslich aller relevanten Zusatze. Dieser Ansatz ist aber aufgrund zu erwartender Systemmigrationen wenig zukunftssicher. Eine zentrale, patienten- und behandlungsschrittbezogene und primar applikationsunabhangige Bildarchivierung ist daher, trotz gelegentlicher Schwierigkeiten bei der Visualisierung bestimmter Datenelemente, vorzuziehen. Die Speicherung von Bilddaten im DICOM-Format ist unabdingbare Voraussetzung.

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.

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.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 (β = 33.57, P0.01), using oral contrast media (β = 13.58, P0.01), placing an intravenous (IV) catheter (β = 5.00, P= 0.04) and scanning patients ≤8 years old (β = 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.Increasing scheduling flexibility to address non-modifiable process variation and completing preparatory activities outside the scanner room were identified as process improvement targets.Scheduling was adapted to utilize three expected total MRI processing times and IV placement was moved outside the scanner room.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.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.

Vendors of medical displays promise a better diagnostic performance using 10- or 11-bit instead of 8-bit monochrome displays. We measured the gain of “Just Noticeable Difference” (JND) steps using high grayscale resolutions and evaluated the preference of radiologists regarding different aspects of image quality. The amount of JND steps was measured on a display using 8-, 10- and 11-bit Look Up Tables (LUT). Radiological images were presented simultaneously using an 8-bit and an 11-bit LUT, radiologists where asked to determine the better image presentation regarding quality parameters like sharpness, contrast and detectability of details. The 10-bit technology realized more than twice the number of JND steps compared to an 8-bit LUT, an 11-bit LUT presented only few additional JND steps. The radiologists did not attest the higher grayscale resolution a better image quality, they regarded the 8-bit technology to show a better sharpness and contrast, although this had no impact on the detectability of details. Our measurements confirmed that the higher grayscale resolution results in a more complete visualization of image information. But radiologists partially judged this as a lack of sharpness and contrast and generally preferred the 8-bit display.

Der Arbeitsablauf (Workflow) in der Radiotherapie (RT) ist gegenwartig durch neue Techniken und Behandlungsparadigmen wie intensitatsmodulierte Radiotherapie (IMRT) und zunehmende bildgestutzte Radiotherapie (IGRT [„image-guided radiotherapy“]) im Umbruch. Daraus resultiert eine starke Zunahme von Daten verschiedener Datenklassen. Dies erfordert fur die Steuerbarkeit einer Abteilung eine zunehmende patienten- und behandlungsserienzentrierte Integration verschiedener Systeme. Der Workflow in einer RT-Abteilung ist multidimensional und multidirektional und umfasst mindestens funf Datenklassen (RT-/Bestrahlungsdaten, patientenbezogene Dokumente wie z.B. Befunde und Arztbriefe, arztliche Akteneintrage, Bilddaten im DICOM-Format [Digital Imaging and Communications in Medicine] sowie Non-DICOM-Bilddaten). Diese Daten mussen sequentiell, u.U. auch im Rahmen von adaptiven Feedbackschleifen in die Patientenhistorie eingebunden werden. Dieses Vorgehen kontrastiert stark mit einer diagnostischen Radiologieabteilung, in der im Wesentlichen DICOM-Bilddaten und Befunde erzeugt werden und im Zugriff bleiben. Diese Daten mussen nach Abschluss des Prozesses kaum noch manipuliert werden. Es handelt sich also um einen uberwiegend unidirektionalen Prozess. Im Gegensatz zu dieser innerhalb der diagnostischen Radiologie etablierten Standardkombination aus Radiologie-Informationssystem (RIS) und Picture Archiving and Communication System (PACS) muss ein integriertes elektronisches Radio-Onkologie-Klinik-Informationssystem (ROKIS) mit Moglichkeiten zur Speicherung/Administration von Bilddaten zusatzliche gesetzliche Rahmenbedingungen berucksichtigen (langere Speicherfristen, prozesssichere Dokumentation von wesentlichen Therapieentscheidungen sowie Abzeichnen von Bestrahlungsplanen und Dosisverschreibungen, komplexe Patienteneinverstandnisse etc.). Der Ubergang zu einer papier- und filmlosen Arbeitsumgebung in der Medizin, insbesondere in der Strahlentherapie, ist vor dem Hintergrund notwendiger Effizienzsteigerungen und steigender Archivierungskosten unausweichlich. Die vorliegende Ubersichtsarbeit stellt eine mogliche apparative und organisatorische Struktur fur ein ROKIS unter Fuhrung eines Krankenhaus-Informationssystems (KIS) vor. Ein solches System vereinigt in einer Kombination und Erweiterung der originaren Merkmale eines Record-and-Verify-(R&V-)Systems Merkmale einer elektronischen Patienten-/Fallakte (ePA) und integriertes Bildmanagement mit einem PACS.

Surgical treatment for chronic subdural haematoma (CSH) has been analysed by applying evidence-based medicine (EBM) criteria earlier. Whether implementation of EBM-derived key factors into an optimised treatment algorithm would improve outcome, however, needs to be clarified.Symptomatic patients with CSH who fulfilled the inclusion criteria were either assigned to an optimised treatment algorithm (OA-EBM group) or to a control group treated by the standard departmental surgical technique (SDST group) in a prospective design. For the OA-EBM algorithm only one burr hole, extensive intraoperative irrigation and a closed system drainage with meticulous avoidance of entry of air was mandatory. A two-catheter technique was used to reduce intracavital air. Final endpoints were neurological outcome (Markwalder Score), recurrence and the amount of intracranial air.A total of 93 out of 117 patients were evaluated accounting for 113 cases because 20 patients had bilateral haematomas. Demographic data of 68 cases in the SDST group did not differ from 45 cases in the OA-EBM group. The Markwalder Score showed greater improvement in the OA-EBM group (0.5 ± 0.6 vs. 1.0 ± 1.0, p = 0.003). The recurrence rate was 18% (12 patients) in the SDST group versus 2% (1 patient) in the OA-EBM group (p0.05). The amount of intracranial air was significantly lower in the OA-EBM group (3.3 ± 5.0 cm(3) vs. 5.2 ± 7.7 cm(3)) with p = 0.04. In the standard group computerised tomography scanning was performed slightly earlier (3 ± 1.7 days vs. 3.6 ± 1.4 days). When comparing only non-recurrent cases in both groups no significant difference was apparent.Implementation of EBM key factors into a treatment algorithm for CSH can improve neurological outcome in a typical neurosurgical department, reduce recurrence and minimise the amount of postoperative air within the haematoma cavity.

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.

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.

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.

Background: Lung protective ventilation using low end-inspiratory pressures and tidal volumes (V T ) 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 H 2 O (P 35 , low V T ) or 45 cm H 2 O (P 45 , high V T ) 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 H 2 O 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 (P 35 /P 45 ) 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 7cm H 2 O), 8.3 ± 2.5/11.6 ± 1.4 ml kg -1 (PEEP 14cm H2O) and 6.5 ± 1.7/11.0 ± 1.6 ml kg -1 (PEEP 21 cm H 2 O); 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 P 45 group at low levels of PEEP. The decrease in nonaerated lung volume was significant for PEEP 14 and 21 cm H 2 O in both groups compared with ZEEP (P < 0.005). Over-inflated lung volumes, although small, were significantly higher in the P 45 group. Significant respiratory acidosis was noted in the P 35 group despite increases in the respiratory rate. Conclusion: Limiting peak inspiratory pressure and V T does not impair alveolar recruitment or promote derecruitment when using sufficient levels of PEEP.

Background Numerous studies suggest setting positive end-expiratory pressure during conventional ventilation according to the static pressure-volume (P-V) curve, whereas data on how to adjust mean airway pressure (P(aw)) during high-frequency oscillatory ventilation (HFOV) are still scarce. The aims of the current study were to (1) examine the respiratory and hemodynamic effects of setting P(aw) during HFOV according to the static P-V curve, (2) assess the effect of increasing and decreasing P(aw) on slice volumes and aeration patterns at the lung apex and base using computed tomography, and (3) study the suitability of the P-V curve to set P(aw) by comparing computed tomography findings during HFOV with those obtained during recording of the static P-V curve at comparable pressures. Methods Saline lung lavage was performed in seven adult pigs. P-V curves were obtained with computed tomography scanning at each volume step at the lung apex and base. The lower inflection point (Pflex) was determined, and HFOV was started with P(aw) set at Pflex. The pigs were provided five 1-h cycles of HFOV. P(aw), first set at Pflex, was increased to 1.5 times Pflex (termed 1.5 Pflex(inc)) and 2 Pflex and decreased thereafter to 1.5 times Pflex and Pflex (termed 1.5 Pflex(dec) and Pflex(dec)). Hourly measurements of respiratory and hemodynamic variables as well as computed tomography scans at the apex and base were made. Results High-frequency oscillatory ventilation at a P(aw) of 1.5 Pflex(inc) reestablished preinjury arterial oxygen tension values. Further increase in P(aw) did not change oxygenation, but it decreased oxygen delivery as a result of decreased cardiac output. No differences in respiratory or hemodynamic variables were observed when comparing HFOV at corresponding P(aw) during increasing and decreasing P(aw). Variation in total slice lung volume (TLVs) was far less than expected from the static P-V curve. Overdistended lung volume was constant and less than 3% of TLVs. TLVs values during HFOV at Pflex, 1.5 Pflex(inc), and 2 Pflex were significantly greater than TLVs values at corresponding tracheal pressures on the inflation limb of the static P-V curve and located near the deflation limb. In contrast, TLVs values during HFOV at decreasing P(aw) (i.e., 1.5 Pflex(dec) and Pflex(dec)) were not significantly greater than corresponding TLV on the deflation limb of the static P-V curves. The marked hysteresis observed during static P-V curve recordings was absent during HFOV. Conclusions High-frequency oscillatory ventilation using P(aw) set according to a static P-V curve results in effective lung recruitment, and slice lung volumes during HFOV are equal to those from the deflation limb of the static P-V curve at equivalent pressures.

OBJECTIVE To determine end-expiratory lung volumes (EELVs) and the distribution of gas and perflubron during low- and high-dose partial liquid ventilation (PLV) in healthy and oleic-acid-injured lungs. DESIGN A prospective, randomized study. SETTING A university medical school laboratory approved for animal research. SUBJECTS Adult sheep. INTERVENTIONS A total of 18 sheep were randomly divided into two groups (healthy and oleic acid lung injury) and received PLV with perflubron at incremental doses. MEASUREMENTS AND MAIN RESULTS Animals were ventilated in a volume-control mode with a positive end-expiratory pressure of 5 cm H2O. Baseline computed tomographic scans of the entire lung were obtained during end-expiratory hold. Thereafter, the animals were randomized to undergo either PLV alone (healthy group) or after oleic acid lung injury was introduced (injury group). In both groups, PLV was induced by instilling 10 mL/kg perflubron into the endotracheal tube over 5 mins (low-dose PLV). At 60 mins after dosing, another set of computed tomographic scans during end-expiratory hold was obtained. Thereafter, another 20 mL/kg perflubron was instilled in both groups (cumulative dose, 30 mL/kg perflubron, high-dose PLV), and computed tomographic scanning was repeated 60 mins later. EELVs were calculated. To study density distribution patterns, the lungs were divided into nine segments, and the mean Hounsfield attenuation number was calculated for each segment. In healthy animals, low-dose PLV did not change EELV (47.5 +/- 8.1 mL/kg vs. 44.5 +/- 6.1 mL/kg at 10 mL/kg perflubron), whereas high-dose PLV significantly increased EELV (58.1 +/- 3.3 mL/kg, p

The present study shows that in calcific AS, the quantification of valvular calcium by EBT is possible with a low intraobserver variability. The extent of valvular calcium is inversely correlated with aortic valve area. Correction for background scatter does not further improve this correlation. The present data suggest that the progression of calcific AS severity by echocardiography is closely linked to a progression in aortic valve calcium. Given these findings and the low interscan variability described by other groups, 3,4 EBT may be a useful imaging modality for noninvasive monitoring of the course of calcific AS by quantification of aortic valve calcium.

Die Teleradiologie bietet sehr viele Moglichkeiten zur Qualitatssicherung und -verbesserung in der Medizin an. Das Spektrum reicht von elektronischen Konsultationen in Notfallen oder elektiven Spezialfragen sowie Doppelbefundung uber neue Modelle kooperativen Arbeitens und der Verwirklichung von Netzstrukturen bis zur technischen Qualitatssicherung und der Integration in institutionenubergreifende, patientenkontrollierte Gesundheitsakten. Regionale Teleradiologienetze mit Serverkonzepten bilden die entstehenden Anforderungen von technischer und organisatorischer Seite ab. Die steigende Mobilitat mit kleineren Untersuchungsgeraten und zusatzlich die erhohte Erreichbarkeit bei Experten mit Minibefundungssystemen in Kombination mit dem Einsatz wissensbasierter Systeme in Referenzdatenbanken und der computerunterstutzten Diagnose (CAD) verandern die radiologische Welt von morgen. Dabei sind, wie in der neuen Rontgenverordnung vorgesehen, qualitatssichernde Vorgaben fur die Teleradiologie selbst zu erstellen, beispielsweise um eine unnotige Strahlenexposition oder eine Gefahrdung der Arzt-Patienten-Beziehung zu verhindern.

Legal prerequisites have substantial influence on the development of teleradiology. At an expert meeting (Mannheim, 8.6.2001) a proposal for a teleradiology article in the new German x-ray ordinance has been set up. An exception of the demand for a doctor trained in radiation protection at the point of examination shall be established for emergency cases. To realize the intended improvement of patient care measurements for quality assurance concerning the medical personnel and processes are necessary. Along with other current developments the basis of secure regional teleradiology networks is now built up.

Specific radiological requirements have to be considered for realization of telemedicine. In this article the goals and requirements for an extensive implementation of teleradiology are defined from the radiological user's point of view. Necessary medical, legal and professional prerequisites for teleradiology are presented. Superior requirements, such as data security and privacy or standardization of communication, must be realized. Application specific requirements, e. g. quality and extent of teleradiological functions as well as technological alternatives, are discussed. Each project must be carefully planned in relation to one's own needs, extent of functions and system selection. Topics like legal acceptance of electronic documentation, reimbursement of teleradiology and liability must be clarified in the future.

Purpose To evaluate electron beam tomography in the detection of acute pulmonary embolism using a new acquisition protocol. Materials and methods 65 patients underwent electron beam tomography (EBT) and v./p. scintigraphy. According to the inclusion criteria 46 patients participated in the study. Contrast enhancement and detectability of pulmonary arteries were scored on a 4 step scale for image quality. The results of prospective detection of pulmonary embolism were compared for both modalities (blinded reading). "Embolism", "questionable embolism" and "no embolism" were used as categories. Results 22/46 patients (48%) showed acute pulmonary embolism. EBT and scintigraphy were discordant in 24% of patients. In EBT 1 false positive and 1 false negative case occurred, scintigraphy demonstrated 2 false negative and 3 false positive cases. 6/9 patients with questionable findings in scintigraphy were correctly classified by EBT to a category "embolism" or "no embolism" as "suspected embolism", EBT displayed a sensitivity of 96.3% and a specificity of 94.7%. Scintigraphy evidenced a sensitivity of 93.7% and a specificity of 84.4%. Conclusions EBT shows better results than scintigraphy for the detection of acute pulmonary emboli. The evaluated new acquisition protocol for EBT seems to be well suited. High vessel contrast and thin slices allow a reliable detection of segmental and subsegmental pulmonary arteries.

Background A significant proportion of acute care neurosurgical patients present to hospital outside regular working hours. The objective of our study was to evaluate the structure of neurosurgical on-call services in Germany, the use of modern communication devices and teleradiology services, and the personal acceptance of modern technologies by neurosurgeons. Materials and Methods A nationwide survey of all 141 neurosurgical departments in Germany was performed. The questionnaire consisted of two parts: one for neurosurgical departments and one for individual neurosurgeons. The questionnaire, available online and mailed in paper form, included 21 questions about on-call service structure; the availability and use of communication devices, teleradiology services, and other information services; and neurosurgeons' personal acceptance of modern technologies. Results The questionnaire return rate from departments was 63.1% (89/141), whereas 187 individual neurosurgeons responded. For 57.3% of departments, teleradiology services were available and were frequently used by 62.2% of neurosurgeons. A further 23.6% of departments described using smartphone screenshots of computed tomography (CT) images transmitted by multimedia messaging service (MMS), and 8.6% of images were described as sent by unencrypted email. Although 47.0% of neurosurgeons reported owning a smartphone, only 1.1% used their phone for on-call image communication. Conclusion Teleradiology services were observed to be widely used by on-call neurosurgeons in Germany. Nevertheless, a significant number of departments appear to use outdated techniques or techniques that leave patient data unprotected. On-call neurosurgeons in Germany report a willingness to adopt more modern approaches, utilizing readily available smartphones or tablet technology.

Purpose : A vendor-independent communication system was needed for a teleradiology project of the state of Baden-Wurttemberg, Germany to connect 13 hospitals. It should also be used for the statewide communication between 48 hospitals. Methods : A client–server solution was described using Dicom-e-mail with additional content encryption according to the OpenPGP standard (Standard e-mail servers). Results : The concept was realized in 2002 with four hospitals (two servers, five clients). Additional security and reliability features were developed during the first year of use. In addition, an open source project was started for a reference implementation of the communication concept. Conclusion : The proof of concept with four hospitals and 1 year of use in clinical routine was successful. The communication concept does allow a variety of different applications including emergency teleradiology as well as the integration into other telemedicine projects without changes of the communication clients (e.g. telepathology).

Telecooperation is used to support care for trauma patients by facilitating a mutual exchange of treatment and image data in use-cases such as emergency consultation, second-opinion, transfer, rehabilitation and out-patient aftertreatment. To comply with data protection legislation a two-factor authentication using ownership and knowledge has been implemented to assure personalized access rights. End-to-end security is achieved by symmetric encryption in combination with external trusted services which provide the symmetric key solely at runtime. Telecooperation partners may be chosen at departmental level but only individuals of that department, as a result of checking the organizational assignments maintained by LDAP services, are granted access. Data protection officers of a federal state have accepted the data protection means. The telecooperation platform is in routine operation and designed to serve for up to 800 trauma centers in Germany, organized in more than 50 trauma networks.

To develop a generic Open Source MRI perfusion analysis tool for quantitative parameter mapping to be used in a clinical workflow and methods for quality management of perfusion data. We implemented a classic, pixel-by-pixel deconvolution approach to quantify T1-weighted contrast-enhanced dynamic MR imaging (DCE-MRI) perfusion data as an OsiriX plug-in. It features parallel computing capabilities and an automated reporting scheme for quality management. Furthermore, by our implementation design, it could be easily extendable to other perfusion algorithms. Obtained results are saved as DICOM objects and directly added to the patient study. The plug-in was evaluated on ten MR perfusion data sets of the prostate and a calibration data set by comparing obtained parametric maps (plasma flow, volume of distribution, and mean transit time) to a widely used reference implementation in IDL. For all data, parametric maps could be calculated and the plug-in worked correctly and stable. On average, a deviation of 0.032 ± 0.02 ml/100 ml/min for the plasma flow, 0.004 ± 0.0007 ml/100 ml for the volume of distribution, and 0.037 ± 0.03 s for the mean transit time between our implementation and a reference implementation was observed. By using computer hardware with eight CPU cores, calculation time could be reduced by a factor of 2.5. We developed successfully an Open Source OsiriX plug-in for T1-DCE-MRI perfusion analysis in a routine quality managed clinical environment. Using model-free deconvolution, it allows for perfusion analysis in various clinical applications. By our plug-in, information about measured physiological processes can be obtained and transferred into clinical practice.

In order to establish diagnostic criteria, colour-coded duplex sonography was performed on 40 patients who had a total of 43 operatively confirmed thyroid lesions which were scintigraphically "cold" (28 adenomas, 8 carcinomas, 4 cases of thyroiditis and 3 cysts). 32 of these patients also had MRT with T2- and T1-weighted images before and after injection of Gd-DTPA (0.1 mmol/kg). Adenomatous nodules and adenomas showed a peripheral vascular halo on colour-coded duplex sonography with a sensitivity of 96% and a specificity of 93%. Malignant lesions showed marked central vascularisation and on B-images irregular marginal structures. Adenomas and adenomatous nodules showed hyperintense areas on T1-weighted unenhanced MR images and/or homogeneous uptake in the lesion (sensitivity 100%, specificity 77%). Malignant lesions typically showed an irregular margin with increased contrast uptake on MRT. If sonography and colour-coded duplex sonography is unable to classify a lesion with any degree of assurance then MRT with Gd-DTPA enhancement should be performed.

Radiation protection is a topic of great public concern and of many scientific investigations, because ionizing radiation is an established risk factor for leukaemia and many solid tumours. Exposure of the public to ionizing radiation includes exposure to background radiation, as well as medical and occupational exposures. A large fraction of the exposure from diagnostic procedures comes from medical imaging. Computed tomography (CT) is the major single contributor of diagnostic radiation exposure. An increase in the use of CTs has been reported over the last decades in many countries. Children have smaller bodies and lower shielding capacities, factors that affect the individual organ doses due to medical imaging. Several risk models have been applied to estimate the cancer burden caused by ionizing radiation from CT. All models predict higher risks for cancer among children exposed to CT as compared to adults. However, the cancer risk associated with CT has not been assessed directly in epidemiological studies. Here, plans are described to conduct an historical cohort study to investigate the cancer incidence in paediatric patients exposed to CT before the age of 15 in Germany. Patients will be recruited from radiology departments of several hospitals. Their individual exposure will be recorded, and time-dependent cumulative organ doses will be calculated. Follow-up for cancer incidence via the German Childhood Cancer Registry will allow computation of standardized incidence ratios using population-based incidence rates for childhood cancer. Dose–response modelling and analyses for subgroups of children based on the indication for and the result of the CT will be performed.

Recent changes in the radiotherapy (RT) workflow through the introduction of complex treatment paradigms such as intensity-modulated radiotherapy (IMRT) and, recently, image-guided radiotherapy (IGRT) with their increase in data traffic for different data classes have mandated efforts to further integrate electronic data management for RT departments in a patient- and treatment-course-centered fashion.: Workflow in an RT department is multidimensional and multidirectional and consists of at least five different data classes (RT/machine data, patient-related documents such as reports and letters, progress notes, DICOM [Digital Imaging and Communications in Medicine] image data, and non-DICOM image data). Data has to be handled in the framework of adaptive feedback loops with increasing frequency. This is in contrast to a radiology department where mainly DICOM image data and reports have to be widely accessible but are dealt with in a mainly unidirectional manner. When compared to a diagnostic Radiology Information System (RIS)/Picture Archiving and Communication System (PACS), additional legal requirements have to be conformed to when an integrated electronic RT data management system is installed. Among these are extended storage periods, documentation of treatment plan approval by physicians and physicist, documentation of informed consent, etc.: Since the transition to a paper- and filmless environment in medicine and especially in radiation oncology is unavoidable, this review discusses these issues and suggests a possible hardware and organizational architecture of an RT department information system under control of a Hospital Information System (HIS), based on combined features of genuine RT Record and Verify (RV) Systems, PACS, and Electronic Medical Records (EMR).