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International audience; Predictive models are central to many scientific disciplines and vital for informing management in a rapidly changing world. However, limited understanding of the accuracy and precision of models transferred to novel conditions (their 'trans-ferability') undermines confidence in their predictions. Here, 50 experts identified priority knowledge gaps which, if filled, will most improve model transfers. These are summarized into six technical and six fundamental challenges, which underlie the combined need to intensify research on the determinants of ecological predictability, including species traits and data quality, and develop best practices for transferring models. Of high importance is the identification of a widely applicable set of transferability metrics, with appropriate tools to quantify the sources and impacts of prediction uncertainty under novel conditions. Predicting the Unknown Predictions facilitate the formulation of quantitative, testable hypotheses that can be refined and validated empirically [1]. Predictive models have thus become ubiquitous in numerous scientific disciplines, including ecology [2], where they provide means for mapping species distributions, explaining population trends, or quantifying the risks of biological invasions and disease outbreaks (e.g., [3,4]). The practical value of predictive models in supporting policy and decision making has therefore grown rapidly (Box 1) [5]. With that has come an increasing desire to predict (see Glossary) the state of ecological features (e.g., species, habitats) and our likely impacts upon them [5], prompting a shift from explanatory models to anticipatory predictions [2]. However, in many situations, severe data deficiencies preclude the development of specific models, and the collection of new data can be prohibitively costly or simply impossible [6]. It is in this context that interest in transferable models (i.e., those that can be legitimately projected beyond the spatial and temporal bounds of their underlying data [7]) has grown. Transferred models must balance the tradeoff between estimation and prediction bias and variance (homogenization versus nontransferability, sensu [8]). Ultimately, models that can Highlights Models transferred to novel conditions could provide predictions in data-poor scenarios, contributing to more informed management decisions.

In Naherholungsräumen von Städten herrscht reger Betrieb: am Tag, aber auch in Randzeiten und teils gar in der Nacht. Wildtiere und deren Lebensräume geraten dadurch unter Druck. In stark frequentierten Gebieten sind Rehe weniger aktiv und für viele Wildtierarten ist der Lebensraum reduziert. Wildruhezonen, eine eingeschränkte Er- schliessung und die Lenkung der Besuchenden verbessern die Lebensbedingungen der Wildtiere., Graf R.F., Signer C., Reifler-Bächtiger M., Wytten- bach M., Sigrist B., Rupf R. (2018). Wildtier und Mensch im Naherholungsraum. Swiss Academies Factsheets 13 (2).

Chick food availability after forestry activities in favour of capercaillie Conservation measures to further the remaining capercaillie populations in Switzerland focus mainly on improving habitat quality of the forests. So far, programs to survey the effect of these forestry measures have been restricted to changes in forest structure and capercaillie presence on the treated areas. Potential changes in arthropod food availability, a key factor for the habitat quality for chicks in their first weeks of life, however, have not been assessed systematically in Central European habitats. We measured the biomass of arthropods in four habitat types: dense, semiopen and open stands and inner forest edges. In our study area in the Swiss Prealps, these habitat types resulted from logging activities in twelve cable-way lines between 2008 and 2011 that were carried out with the aim to improve habitat quality for capercaillie. Arthropod availability varied strongly between plots and high numbers of individuals could be observed in all four habitat types. Coleoptera accounted for more than half of the total dry weight of the catch. Summing up the three most important arthropod groups for the chick diet as reported in literature (spiders, ants and lepidoptera larvae), open stands, forest edges and semiopen stands yielded higher arthropod biomasses than the dense stands that had not been treated in the logging campaigns. In this case study, habitat improvement measures increased the arthropod food supply, and thus probably improved the conditions for capercaillie chicks in the first weeks of their development.

Recognition of pathogens by the innate immune system relies on germline-encoded pattern recognition receptors (PRRs) that recognize unique microbial molecules, so-called pathogen-associated molecular patterns (PAMPs). Nucleic acids and their derivatives are one of the most important groups of PAMPs, and are recognized by a number of surface-associated as well as cytosolic PRRs. Cyclic GMP-AMP synthase (cGAS) recognizes the presence of pathogen- or host-derived dsDNA in the cytosol and initiates type-I-IFN production. Here, we describe a methodology that allows for evaluating the association of cGAS with released bacterial dsDNA during Francisella novicida infection of macrophages, by fluorescence confocal microscopy. This method can be adapted to the study of cGAS-dependent responses elicited by other intracellular bacterial pathogens and in other cell types.

Advances in MRI technology have greatly improved visualization of the radio-carpal region. With todays high-resolution imaging, even very small anatomic structures like the triangular fibrocartilage may be seen. Established indications include the osteonecroses (scaphoid and lunate); however, MR images always should be evaluated in conjunction with plain radiographs. By delineating bone marrow edema, MRI is well suited for the detection of microfractures. Visualization of small soft tissue tumors, soft tissue extension of bone tumors and for staging of tumors in general may also be regarded as indications generally agreed upon. Promising indications include pathology of ligaments and similar structures.

To determine local tumor control after CT-guided brachytherapy at various dose levels and the prognostic impact of extensive cytoreduction in colorectal liver metastases.Seventy-three patients were treated on a single-center prospective trial that was initially designed to be randomized to three dose levels of 15 Gy, 20 Gy, or 25 Gy per lesion, delivered in a single fraction. However, because there was a high rate of cross-over of subjects from higher to lower dose levels, this study is better understood as a prospective trial with three dose levels. No upper size limit for the metastases was applied. We assessed time to local progression, progression-free survival, and overall survival.According to safety constraints cross-over was performed. The final assignment was n = 98, n = 68, and n = 33 in the 15-Gy, 20-Gy, and 25-Gy groups, respectively. Median diameter of the largest tumor lesion in each patient was 5 cm (range, 1-13.5 cm). Estimated mean local recurrence-free survival for all lesions was 34 months (median not reached). The group assigned to 15 Gy after cross-over displayed 34 local recurrences out of 98 lesions; 20 Gy, 15 out of 68 lesions; 25 Gy, 1 out of 33 lesions. The difference between the 25-Gy and the 20-Gy or 15-Gy group was significant (p0.05). Repeated local tumor ablations were the most prominent factor for increased survival and dominated additional systemic antitumor treatments.Local tumor control after CT-guided brachytherapy of colorectal liver metastases demonstrated a strong dose dependency. The role of extensive minimally invasive tumor ablation in metastatic colorectal cancer needs to be further established.

Capercaillie (Tetrao urogallus) populations in Switzerland declined seriously in the past decades. The national capercaillie action plan defines actions to improve forest structure and composition in order to further the populations of the largest grouse species. These habitat measures should focus on improving summer habitat for hens with chicks, because winter habitats are available in good quality and quantity. However, our knowledge on reproduction habitats in alpine conditions is limited. In this study, we investigated microclimatic conditions, i.e. plant wetness, and movement ability of barn fowl chicks in seven characteristic field layer types in the northern Swiss Lower Alps. In the experiment on movement ability, we worked with barn fowl instead of capercaillie chicks for methodological reasons. In the bilberry-dominated vegetation, we measured a significantly lower quantity of water than in the vegetation types without bilberry. In the movement experiment, we found no significant differences between the vegetation types. As a qualitative result, we observed that the chicks moved easily even in high (> 30 cm) and close bilberry vegetation. Our results suggest that bilberry-dominated vegetation provides better conditions for grouse chicks than wet meadows and pastures, because less water adheres to the bilberry plants. Thus, the chicks get less wet in bilberry vegetation, which probably has a positive influence on the survival of the chicks. Even tall and dense vegetation seems not to impede the movement of the chicks. The results of our experiment may not be directly transferable to the demands of capercaillie chicks. Nevertheless, our study provides further evidence for the importance of bilberry as capercaillie chick habitat, especially in regions with high precipitations.

Rationale and Objectives Cardiac transplant vasculopathy is the most important long-term complication of heart transplantation, with overlapping features with conventional, atherosclerotic coronary artery disease. The aim of this study was to determine the progression of coronary artery disease after heart transplantation by measuring total coronary calcium load. Materials and Methods After heart transplantation, 185 patients were serially examined using electron-beam computed tomography for coronary calcium load for clinical reasons. The mean time between the initial examination and the follow-up scan was 566 days (range, 126–1,436). Coronary calcium load was measured by the Agatston method, and the total calcium scores at both examinations were compared between patients taking and those not taking lipid-lowering medications (statins). Results Patients not taking statins ( n = 94) displayed a median annualized percentage increase in total calcium score of 0 Agatston units, whereas patients taking at least the lowest recommended daily dose of a statin ( n = 84) displayed an annualized percentage decrease of 11 Agatston units. The difference was not statistically significant (Wilcoxon's rank-sum test, P = .35). Only 17 patients had increases of > 24 Agatston units, and eight of them were taking statins (χ 2 test, P = .99). Conclusion The annual rate of progression of coronary calcium load after heart transplantation is low. In this investigation, no beneficial effects of statins could be detected.

The potential of colloidal subdomain ferrite particle suspensions (SDP) ('magnetic fluids'), exposed to an alternating magnetic field, is evaluated for hyperthermia. Power absorption measurements of different magnetic fluids are presented in comparison to multidomain ferrite particles (MDP). Variations with frequency as well as magnetic field strength have been investigated. The experimental results clearly indicate a definite superiority of even non-optimized magnetic fluids over MDP ferrites regarding their specific absorption rate (SAR). Based on the work of Shliomis et al. (1990) and Hanson (1991), a solid-state physical model is applied to explain the specific properties of magnetic fluids with respect to a possible use in hyperthermia. The experimentally determined SAR data on magnetic fluids are used to estimate the heating capabilities of a magnetic induction heating technique assuming typical human dimensions and tissue parameters. It is considered that for a moderate concentration of 5 mg ferrite per gram tumour (i.e. 0.5% w/w) and clinically acceptable magnetic fields, intratumoral power absorption is comparable to RF heating with local applicators and superior to regional RF heating (by comparison with clinical SAR measurements from regional and local hyperthermia treatments). Owing to the high particle density per volume, inductive heating by magnetic fluids can improve temperature distributions in critical regions. Furthermore, localized application of magnetic fluids in a tumour might be easier and less traumatic than interstitial implantation techniques.

Predictive species distribution models have become increasingly common in conservation management. Among them, envelope-based approaches like the Ecological Niche Factor Analysis (ENFA) are particularly advantageous, as they require only presence data. Based on the assumption that the absolute frequency of species presence is a direct indicator of habitat suitability (HS), habitat suitability indices (HSI) are computed. However, this assumption may be misleading when the scarcity of optimal habitat forces most of the individuals to live in suboptimal conditions. This often happens when the environmental conditions in the study area represent only a marginal part of the species fundamental niche. In this study we propose three new HS algorithms for ENFA models, which address such ‘edge of niche’ situations. The first algorithm (area-adjusted median, Ma) takes the availability of environmental conditions in the study area into account, the second (median + extremum, Me) addresses situations where the species’ optimum is at or beyond the extremum of the investigated environmental gradient, and the third (area-adjusted median + extremum, Mae) combines both approaches. These algorithms were applied to two populations of capercaillie (Tetrao urogallus), situated in different positions relative to the environmental gradient represented in the respective study area, and compared with the classical median algorithm (M). We evaluated the models using cross-validation and a comparison with an expert model based on external data. In both study areas, the HS maps obtained with the three new algorithms differed visibly from those calculated with the median algorithm. Cross-validation and comparison with external data showed that the new algorithms always provided better models, with the extremum-based algorithms (Me and Mae) performing best. We conclude that the new algorithms can extend the applicability of ENFA-models to a broader range of conservation-relevant species by improving HS calculations for skewed species-habitat relationships in marginal habitats.

To retrospectively compare the diagnostic accuracy of three cardiac magnetic resonance (MR) imaging approaches for the detection of histologic and immunohistologic criteria (reference standard) proved myocardial inflammation in patients clinically suspected of having chronic myocarditis (CMC).Cardiac MR imaging was performed in 83 consecutive patients (55 male, 28 female; mean age, 44.8 years +/- 17.7 [standard deviation]) clinically suspected of having CMC, after written informed consent was obtained according to guidelines of the local ethics committee, which approved the study. T2-weighted triple-inversion-recovery imaging to calculate the edema ratio (ER), T1-weighted imaging before and after contrast agent administration to calculate the myocardial global relative enhancement (gRE), and inversion-recovery gradient-echo imaging to evaluate areas of late gadolinium enhancement (LE) were performed. The MR results were correlated with the endomyocardial biopsy (EMB) findings to detect intramyocardial inflammation and cardiotropic viral genomes analyzed at polymerase chain reaction assay. For statistical analyses, receiver operating characteristic analysis and the Wilcoxon test for unpaired data were used because the Kolomogorov-Smirnov test revealed a distribution of data that was different from normality.Intramyocardial inflammation and cardiotropic viral persistence were confirmed at immunohistologic analysis in 48 and 49 of the 83 patients, respectively. The sensitivity, specificity, and diagnostic accuracy of the MR parameters, as compared with the immunohistologic detection of inflammation, were, respectively, 62%, 86%, and 72% for gRE; 67%, 69%, and 68% for ER; and 27%, 80%, and 49% for LE. Cardiac MR-derived gRE, ER, and LE were not associated with polymerase chain reaction proof of viral genomes.In patients clinically suspected of having CMC, increased gRE and ER indicating inflammation were common findings that could be confirmed at immunohistologic analysis, whereas LE had low sensitivity and accuracy. Cardiac MR imaging may be helpful in detecting intramyocardial inflammation noninvasively, but it fails to depict viral persistence.

The purpose of this study was to evaluate radiological-interventional central venous port catheter corrections in migrated/malpositioned catheter tips.Thirty patients with migrated/malpositioned port catheter tips were included in this retrospective analysis. To visualize the catheter patency a contrast-enhanced port catheter series was performed, followed by transfemoral port catheter correction with various 5-F angiographic catheters (pigtail; Sos Omni), gooseneck snares, or combinations thereof.One patient showed spontaneous reposition of the catheter tip. In 27 of 29 patients (93%), radiological-interventional port catheter correction was successful. In two patients port catheter malposition correction was not possible, because of the inability to catch either the catheter tip or the catheter in its course, possibly due to fibrin sheath formation with attachment of the catheter to the vessel wall. No disconnection or port catheter dysfunction was observed after correction.We conclude that in migrated catheter tips radiological-interventional port catheter correction is a minimally invasive alternative to port extraction and reimplantation. In patients with a fibrin sheath and/or thrombosis port catheter correction is often more challenging.

Purpose: To assess image quality and overall accuracy of 3-Tesla (3T)-sustained high-resolution magnetic resonance (MR) imaging for diagnostic preoperative workup in suspected rectal carcinoma. Material and Methods: Twenty-three patients with suspected rectal cancer underwent unenhanced and contrast-enhanced fat-suppressed pelvic high-resolution MR imaging using a four-channel phased-array pelvic coil at 3T. Image quality, tumor stage, distance from the anorectal margin, and sphincter-saving resectability were prospectively assessed by two blinded readers. The results were correlated with clinical, surgical, and histopathologic findings. Results: In all 23 patients, MR images were of diagnostic quality, and malignancy was correctly identified in 21 patients. The accuracy for determining sphincter-saving resectability was 100% (19/19). T stage and N stage were correctly diagnosed in 95% and 91%, respectively. MRI allowed correct identification of tumor extension and its relation to surgically relevant pelvic structures including the anorectal margin and mesorectal fascia. Transverse T2-weighted fast spin-echo images compared superiorly to all other sequences for the diagnosis of mesorectal infiltration and lymph node involvement. Moreover, transverse fat-suppressed contrast-enhanced T1-weighted images were valuable for identifying tumor infiltration, while sagittal sections were useful for the detection of longitudinal tumor extension. Conclusion: MR imaging with phased-array receiver coils at 3T facilitated both visualization of different pathologic conditions of the rectum and accurate determination of tumor stage in rectal carcinomas. Thus, this noninvasive diagnostic approach appeared highly suitable for the assessment of patients with suspected rectal carcinoma.

Capercaillie (Tetrao urogallus) is a large, endangered forest grouse species with narrow habitat preferences and large spatial requirements that make it susceptible to habitat changes at different spatial scales. Our aim was to evaluate the relative power of variables relating to forest versus landscape structure in predicting capercaillie occurrence at different spatial scales. We investigated capercaillie–habitat relationships at the scales of forest stand and forest-stand mosaic in 2 Swiss regions. We assessed forest structure from aerial photographs in 52 study plots each 5 km2. We classified plots into one of 3 categories denoting the observed local population trend (stable, declining, extinct), and we compared forest structure between categories. At the stand scale, we used presence–absence data for grid cells within the plots to build predictive habitat models based on logistic regression. At this scale, habitat models that included only variables relating to forest structure explained the...

We compared in vivo blood flow and pulsatility after different types of Fontan operation using magnetic resonance imaging. A total of 37 consecutive patients (mean age 19±7.9 years, 7.3±3.2 years after Fontan operation), 7 with atriopulmonary anastomosis (APC), 18 with intra-atrial lateral tunnel (LTFO) and 12 with extracardiac Fontan (ECFO) were studied using magnetic resonance phase-contrast velocity mapping. Blood flow (volume flow) in the superior vena cava (SVC), inferior vena cava (IVC) and both pulmonary arteries were measured and a pulsatility index was calculated for each vessel. For all modifications, the blood flow distribution between the SVC and IVC was normal (1 : 2). Patients with APC had a normal pulsatility, a dilated right atrium, partial backward flow in the IVC and physiological blood flow distribution between the pulmonary arteries. LTFO and ECFO patients had no retrograde flow in the IVC, equal blood flow distribution between the pulmonary arteries and very low or absent pulsatility. MRI allows hemodynamic quantification and characterization of various types of Fontan modifications and may be a valuable tool to predict Fontan failure. Despite showing normal pulsatility, patients with APC have right atrial dilatation and partial backward flow in the IVC, demonstrating suboptimal Fontan circulation. LTFO and ECFO both produce unidirectional antegrade flow in the IVC but pulsatility is very low or absent, which may promote poor pulmonary artery growth and increase of pulmonary vascular resistance contributing to late Fontan failure.

A systematic comparison of three-dimensional MR(magnetic resonance)thermography and planning calculations in phantoms for the hyperthermia (HT) SIGMA-Eye applicator. We performed 2 × 6 experiments in a homogeneous cylindrical and a heterogeneous elliptical phantom by adjusting 82 different patterns with different phase control inside an MR tomograph (Siemens Magnetom Symphony, 1.5 Tesla ). For MRthermography, we employed the proton resonance frequency shift method with a drift correction based on silicon tubes. For the planning calculations, we used the finite-difference time-domain(FDTD) method and, in addition, modeled the antennas and the transforming network. We generated regions according to a segmentation of bones and tissue, and used an interpolation technique with a subgrid of 0.5 cm size at the interfaces. A Gauss-Newton solver has been developed to adapt phases and amplitudes. A qualitative agreement between the planning program and measurements was obtained, including a correct prediction of hot spot locations. The final deviation between planning and measurement is in the range of 2– 3 W ∕ kg , i.e., below 10%. Additional HT phase and amplitude adaptation, as well as position correction of the phantom in the SIGMA-Eye, further improve the results. HT phase corrections in the range of 30– 40 ° and HT amplitude corrections of ± 20 – 30 % are required for the best agreement. The deviation ∣ MR-FDTD ∣ , and the HT phase/amplitude corrections depend on the type of phantom, certain channel groups, pattern steering, and the positioning error. Appropriate agreement between three-dimensional specific absorption rate distributions measured by MR-thermography and planning calculations is achieved, if the correct position and adapted feed point parameters are considered. As long as feed-point parameters are uncertain (i.e., cannot be directly measured during therapy), a prospective planning will remain difficult. However, we can use the information of MRthermography to better predict the patterns in the future even without the knowledge of feed-point parameters.

Iodine-containing polyvinyl alcohol polymer (I-PVAL) is a novel precipitating liquid embolic that allows for artifact-free evaluation of CT angiography (CTA). As accurate aneurysm volumetry can be performed with multidetector CTA, we determined volumes of experimental aneurysms before, immediately after, and 4 weeks after embolization of 14 porcine experimental carotid sidewall aneurysms with this liquid embolic. An automated three-dimensional software measurement tool was used for volumetric analysis of volume-rendering CTA data. Furthermore, intra-aneurysmal pressure changes during liquid embolization were measured in four silicone aneurysms and potential polymer volume changes within 4 weeks were assessed in vitro. Liquid embolic injection was performed during temporary balloon occlusion of the aneurysm neck, resulting in a mean occlusion rate of 98.3%. Aneurysms enlarged significantly during embolization by 61.1 +/- 28.9%, whereas a significant shrinkage of 5.6 +/- 2.7% was observed within the follow-up period. Histologic analysis revealed an inflammatory foreign body reaction with partial polymer degradation. In silicone aneurysm models, intra-aneurysmal pressure remained unchanged during liquid embolic injection, whereas balloon inflation resulted in a mean pressure increase of 31.2 +/- 0.7%. No polymer shrinkage was observed in vitro. The aneurysm enlargement noted was presumably due to pressure elevation after balloon inflation, which resulted in dilatation of the weak venous wall of the newly constructed aneurysm--another shortcoming of this experimental aneurysm model. The volume decrease after 4 weeks expressed partial polymer degradation.

Alterations in presynaptic and postsynaptic dopaminergic system and cerebral glucose metabolism in corticobasal degeneration (CBD) were assessed to evaluate the potential usefulness of different imaging methods for CBD. 123I-FP-CIT/123I-β-CIT SPECT and 123I-IBZM SPECT as well as 18F-FDG PET were performed in eight CBD patients. Decreased presynaptic dopamine transporter binding was found in all CBD patients while D2 receptor binding was reduced in only one patient. 18F-FDG PET displayed a contralateral hypometabolism in cortical and subcortical areas in seven out of eight patients. Our results demonstrate that glucose metabolism and DAT are reduced, while D2 receptors may be frequently preserved in CBD. © 2006 Movement Disorder Society

Assessment of perfusion with 15O-labelled water (H215O) requires measurement of the arterial input function (AIF). The arterial time activity curve (TAC) measured using the peripheral sampling scheme requires corrections for delay and dispersion. In this study, parametrizations with and without arterial spillover correction for fitting of the tissue curve are evaluated. Additionally, a completely noninvasive method for generation of the AIF from a dynamic positron emission tomography (PET) acquisition is applied to assess perfusion of pelvic tumours. This method uses a volume of interest (VOI) to extract the TAC from the femoral artery. The VOI TAC is corrected for spillover using a separate tissue TAC and for recovery by determining the recovery coefficient on a coregistered CT data set. The techniques were applied in five patients with pelvic tumours who underwent a total of 11 examinations. Delay and dispersion correction of the blood TAC without arterial spillover correction yielded in seven examinations solutions inconsistent with physiology. Correction of arterial spillover increased the fitting accuracy and yielded consistent results in all patients. Generation of an AIF from PET image data was investigated as an alternative to arterial blood sampling and was shown to have an intrinsic potential to determine the AIF noninvasively and reproducibly. The AIF extracted from a VOI in a dynamic PET scan was similar in shape to the blood AIF but yielded significantly higher tissue perfusion values (mean of 104.0 +/- 52.0%) and lower partition coefficients (-31.6 +/- 24.2%). The perfusion values and partition coefficients determined with the VOI technique have to be corrected in order to compare the results with those of studies using a blood AIF.

The purpose of the study was to evaluate the feasibility and effectiveness of direct porto-caval shunts in patients with Budd-Chiari syndrome (BCS) in whom there is no access to the hepatic veins during transjugular intrahepatic portosystemic shunt (TIPSS). We included six consecutive patients with fulminant/acute Budd-Chiari syndrome (mean age: 35 years) in whom a conventional TIPSS was not possible due to inaccessible hepatic veins. We performed a direct porto-caval shunt via a transhepatic approach. Patients were followed up by means of clinical examination, laboratory investigations, and Doppler ultrasound. TIPSS implantation from the inferior vena cava (IVC) was successful in all six patients (100%). The median transhepatic shunt length was 9 cm (8-10 cm). No procedure-related complications were observed in our patients. Early shunt occlusion occurred in three out of six patients (50%). In all three of these patients, the stent used to stabilize the shunt ended 1-2 cm before reaching the IVC. All occlusions were successfully recanalized. One of these patients developed recurrent early shunt as well as mesenteric and splenic vein occlusions. She died 7 days after TIPSS placement due to an unmanageable coagulation disorder. The remaining five patients were followed up by planned clinical examination and laboratory investigations (mean follow-up time was 15 months; patient 1 was followed up for 13 months, patient 2 for 14 months, patient 3 for 15 months, and patients 4 and 5 for 16 months) and all displayed a complete and durable resolution of liver failure and ascites without reintervention. In patients with acute liver failure originating from BCS and inaccessible hepatic veins, a direct transhepatic porto-caval shunt can be performed safely and effectively under ultrasound guidance. Future studies in larger patient groups should investigate if the patency of transcaval TIPSS with long transhepatic shunt segments is similar compared to conventional TIPSS via the hepatic vein.

Capercaillie populations in Switzerland declined significantly during the 20th century. The loss of suitable habitats is considered to be the main reason for this decline. For the Pre-Alpine region of the Schwägalp, aerial photographs and a statistic model were used to quantify changes in the availability and distribution of capercaillie habitat. We detected a loss of suitable habitats. However, this loss alone can not explain the extensive decline in the population of this endangered species.

The purpose was to evaluate the safety and efficacy of high-dose-rate (HDR) CT-guided interstitial brachytherapy in the treatment of extrahepatic, extrapulmonary, secondary malignancies. Nineteen patients were included in this prospective study. The median age was 66 years (49-77). Underlying primaries comprised colorectal carcinomas in six, renal cell carcinoma in three, pancreatic carcinoma in three, cervical cancer in two, endometrial cancer in two and NSCLC, breast cancer and sarcoma in one patient each. All patients had undergone extensive pretreatments. CT-guided HDR brachytherapy employed a 192Iridium source. Dose planning for brachytherapy was performed using 3D CT data acquired after CT-guided percutaneous applicator positioning. MRI follow-up was performed 6 weeks and every 3 months post intervention. Primary endpoints were complications, local tumor control and progression-free survival. The median tumor diameter was 6 cm (2-15 cm). Tumor locations included the hepatoduodenal ligament, mesentery, adrenal gland, mesogastrium and local recurrences after rectal or pancreatic cancer. The minimal median dose in the target volume was 11 Gy (4-18 Gy). Minor complications comprised pain and fever (n=6, 32%). Major complications included one hospital death of unknown causes (n=1; 5%). Median follow-up was 7 months (1-16). Four patients (21%) died during the follow-up period. Local tumor control was 76.5% after 6 months and progression-free survival 47% after 6 months. Minimally invasive CT-guided HDR brachytherapy is safe and effective in the palliative treatment of extrahepatic, extrapulmonary secondary malignancies.

The aim of this prospective double-blind and randomized study was to assess whether intraluminal brachytherapy of de novo transjugular intrahepatic portosystemic shunts (TIPS) can prevent significant shunt stenosis.Forty patients with portal hypertension due to liver cirrhosis were enrolled. In the irradiation group of 20 patients, the gamma radiation source, iridium-192, was introduced into the shunt within a special balloon catheter that allows the radionuclide to be centered within the shunt. A dose of 14 Gy in the shunt wall at a depth of 2 mm should be achieved. In the control group of 20 patients, a dummy source was used. Doppler sonography was performed immediately, 1 day, 1 week, 4 weeks, and 3 months after TIPS placement and then at an interval of 3 months during the first year. The primary end point of the study was the percentage of patients who developed significant shunt stenosis, defined as a reduction of maximum flow velocity below 50 cm/sec in the proximal part of the shunt 1 cm from the entry of the stent into the punctured portal vein branch. Fisher's exact test was used.The TIPS procedure was technically successful in all patients. Seventeen patients in the irradiation group and 15 patients in the control group were followed up. Five patients (29.4%) in the irradiation group and 10 (66.7%) in the control group developed significant shunt stenosis during the first year after TIPS placement (p = 0.0392). The time until such stenosis occurred did not differ significantly between the two groups.Our results suggest that brachytherapy can be useful in reducing the incidence of TIPS stenosis. A larger study with histopathologic analysis may be needed to confirm these findings.

We studied the midbrain SERT availability in patients with major depression and assessed the relation of SERT occupancy by citalopram to the treatment response. 21 non-medicated patients with major depression and 13 healthy controls were examined by [(123)I]-ADAM SPECT. The midbrain SERT availability (SERT V(3)'') was calculated using individual MRI scans. In 13/21 patients SPECT was repeated 7 days after oral medication with citalopram (10 mg/day). We found no significant difference in the mean midbrain SERT availability between the studied patients with major depression and healthy controls (0.86 +/- 0.27 vs. 0.71 +/- 0.44, p = 0.069). The mean SERT occupancy accounted to 61%. The degree of SERT blockade by citalopram did not correlate with the reduction in HAMD total score. Treatment with low-dosed citalopram caused individually variable occupancy of the midbrain-SERT and a rapid clinical improvement in 54% of the investigated patients.

Die minimal-invasiven, interventionell-radiologischen Therapieverfahren leisten einen wichtigen Beitrag bei der Behandlung von primaren und sekundaren Knochentumoren. Beim Osteoidosteom hat die lokale Thermoablation die offene Operation weitgehend als Therapie der Wahl abgelost und weist primare Erfolgsraten von 80–100% auf. Bei Therapieversagen der primaren Ablation kann in 99% der Falle durch eine erneute Ablation Schmerzfreiheit erreicht werden. Bei schmerzhaften Knochenmetastasen sind die perkutane Zementinjektion und die Thermoablation alternative oder additive Behandlungsoptionen zur Standardtherapie. Da die Thermoablation durch Destruktion der sensiblen Schmerzfasern zwar eine rasche Reduktion der Symptomatik ermoglicht, aber keine stabilisierende Wirkung besitzt, sind die Thermoablation und die perkutane Zementinjektion in Kombination sinnvoll.

Object To evaluate iodine-containing polyvinyl alcohol (I-PVA) as a precipitating liquid embolic agent, implant characteristics—including radiopacity, setting behavior, and biocompatibility—were studied in an aneurysm model in swine. Methods Twelve broad-based carotid artery (CA) sidewall aneurysms were surgically constructed in six pigs. Iodine-containing polyvinyl alcohol dissolved in dimethyl sulfoxide (DMSO) was injected during temporary balloon occlusion bridging the aneurysm neck. Control angiography as well as multidetector row computerized tomography (CT) angiography was performed after 4 weeks. Harvested aneurysms were investigated histopathologically and by 3-tesla high-field magnetic resonance (MR) imaging. The mean degree of aneurysm occlusion achieved was 96%. In two aneurysms a minimal protrusion of I-PVA into the CA lumen was observed. During one embolization, leakage of the liquid embolic agent due to DMSO-induced damage of the microcatheter resulted in CA occlusion. Aneurysms embolized with I-PVA could be discriminated clearly from the parent artery on CT angiograms because there was no beam-hardening artifact. High-field MR imaging allowed a detailed depiction of the liquid embolic distribution within the aneurysm. Histologically, a mild to moderate inflammatory response was found in successfully embolized aneurysms, and the polymer mass was frequently covered by a membrane of fibroblasts and endothelial cells. Conclusions Iodine-containing polyvinyl alcohol is a ready-to-use liquid embolic agent clearly visible under fluoroscopy; additives are not required. The setting behavior allows for controlled delivery in aneurysm cavities. Histological studies performed 4 weeks after embolization revealed no sign of toxic tissue response to the liquid embolic agent. Overall, I-PVA exhibits interesting implant characteristics in that radiopaque admixtures are not necessary, thus allowing for artifact-free evaluation of treated aneurysms by using CT and MR angiography.

BACKGROUND The objective of this study was to evaluate noninvasive magnetic resonance (MR) thermography for the monitoring of regional hyperthermia (RHT) in patients with soft tissue sarcomas of the lower extremities and pelvis. METHODS Noninvasive MR monitoring during RHT was performed in 9 patients who had high-risk soft tissue sarcomas of the lower extremities or pelvis during neoadjuvant chemotherapy plus RHT in the scope of the European Organization for Research and Treatment of Cancer 62961/European Society for Hyperthermic Oncology RHT-95 study. Anatomic and temperature-sensitive data sets were acquired every 10 minutes before and during RHT (using gradient-echo-sequences with variable echo times). MR temperature distributions were derived from the phase differences by using the proton-resonance frequency shift method. A phase convolution setting phase shifts to zero in the fat tissue was performed as a drift correction. The mean MR temperatures in the tumor and muscles and the index temperatures (e.g., T90, which covers 90% of the target volume) and thermal doses were determined and compared with pathohistologic responses and direct temperature measurements if available. RESULTS Thirty of 72 MR-thermography data sets (>40% of heat sessions) were evaluable. A significant correlation was observed between pathohistologic response (defined as a necrosis rate ≥90%) and standardized thermal parameters, such as thermal dose cumulative equivalent minutes at 43°C to 90% of the target volume (T90) (P = .050), mean T90 (P = .048), or T50 (P = .050). The correlation of 13 conventional temperature measurements performed in selected patients and sessions invasively in the tumor or noninvasively in rectum and bladder revealed an excellent correlation with MR temperatures (R2 = .96). CONCLUSIONS Noninvasive MR thermography of soft tissue sarcoma was feasible and suitable for validating the quality of heating during RHT. Cancer 2006. © 2006 American Cancer Society.

Thermotherapy using magnetic nanoparticles (nano cancer therapy) is a new concept of local tumour therapy, which is based on controlled heating of intra-tumoural injected magnetic nanoparticles. The aim of this study was to evaluate the usefulness of PET with a recently introduced amino acid tracer O-(2-[18F]fluoroethyl)-]L-tyrosine (FET) for targeting the nanoparticles implantation.Eleven patients with glioblastoma recurrences underwent MR and FET-PET imaging for planning of the nano cancer therapy. Thereafter, the gross tumour volumes (GTV) were defined, taking into consideration the results of both imaging tools.The MRI-based mean GTV was 24.3 cm3 (range 2.5-59.7) and the PET-based mean GTV 31.9 cm3 (range 5.2-77.9). On the average the MRI identified an additional 8.9 +/- 4.7 cm3 and the FET-PET scan-an additional 16.5 +/- 15.2 cm3 outside of the common GTV (15.4 +/- 11.0 cm3). The mean final GTV accounted to 33.8 cm3 (range, 5.2-77.9). The additional information of FET-PET led to an increase in GTV by 22-286% in eight patients and to a decrease of 23% and 26%, respectively, in two patients. In one patient, the final GTV was defined on the basis of MRI data only.FET-PET adds important information on the actual tumour volume in recurrent glioblastomas and is highly valuable for defining the target volume for the nano cancer therapy.

Background This study focuses on the correlation of the signal intensity (SI) of the bowel wall in magnetic resonance (MR) colonography with the inflammation activity in Crohn's disease. Material and methods We performed MR colonography in 42 patients and compared the change of the SI of the bowel wall (T1-weighted/paramagnetic contrast medium) with colonoscopic findings. Results Change of the SI and colonoscopically assessed inflammatory activity are significantly correlated ( r =.676, P ≤.01). Conclusion The degree of the contrast enhancement of the bowel wall may be a criterion for the degree of inflammation in Crohn's disease.

Background: Nuclear medicine imaging is increasingly used in the evaluation of tumors of the head and neck. In the current study, we assess the value of single-photon emission tomography (SPECT) us

This study assessed the value of image fusion with (18)F-fluorodeoxyglucose-positron emission tomography (FDG-PET) and magnetic resonance imaging (MRI) in patients suspected of having pancreatic cancer.32 patients (12 women, 20 men; age 24-79 years; mean 56.6 years) were included. All patients underwent whole-body FDG-PET examinations and contrast-enhanced MRI. Image fusion used a semiautomatic voxel-based algorithm. Separate reading, side-by-side analysis and evaluation of fused PET/MRI images were performed. Results were correlated to histopathology (n = 30), or clinical follow-up (n = 2).15/32 patients had pancreas cancer and 17/32 patients benign disease. The sensitivity and specificity for cancer detection by FDG-PET were 93 and 41% for visual and 86 and 58% for semiquantitative analysis whereas MRI achieved 100 and 76% respectively. Topographical assignment of PET foci by image fusion was superior to side-by-side analysis in 11/39 (28%) foci (in 8/32 patients). However, a true impact on therapeutic strategy was observed only in 1/8 patients as the presence of multiple metastases, irresectable primaries or medical reasons for inoperability prevented a curative setting.Compared to side-by-side analysis, PET/MRI image fusion improves the anatomical assignment and interpretation of FDG foci. The therapeutic benefit for the patient however is limited in patients with multiple lesions or incurable primaries.

The concept of magnetic fluid hyperthermia is clinically evaluated after development of the whole body magnetic field applicator MFH 300F and the magnetofluid MFL 082AS. This new system for localized thermotherapy is suitable either for hyperthermia or thermoablation. The magnetic fluid, composed of iron oxide nanoparticles dispersed in water, must be distributed in the tumour and is subsequently heated by exposing to an alternating magnetic field in the applicator. We performed a feasibility study with 22 patients suffering from heavily pretreated recurrences of different tumour entities, where hyperthermia in conjunction with irradiation and/or chemotherapy was an option. The potential to estimate (by post-implantation analyses) and to achieve (by improving the technique) a satisfactory temperature distribution was evaluated in dependency on the implantation technique.Three implantation methods were established: Infiltration under CT fluoroscopy (group A), TRUS (transrectal ultrasound)--guided implantation with X-fluoroscopy (group B) and intra-operative infiltration under visual control (group C). In group A and B the distribution of the nanoparticles can be planned prior to implantation on the basis of three-dimensional image datasets. The specific absorption rates (SAR in W/kg) can be derived from the particle distribution imaged via CT together with the actual H-field strength (in kA/m). The temperature distribution in the tumour region is calculated using the bioheat-transfer equation assessing a mean perfusion value, which is determined by matching calculated temperatures to direct (invasive or endoluminal) temperature measurements in reference points in or near the target region.Instillation of the magnetic fluid and the thermotherapy treatments were tolerated without or with only moderate side effects, respectively. Using tolerable H-field-strengths of 3.0-6.0 kA/m in the pelvis, up to 7.5 kA/m in the thoracic and neck region and10.0 kA/m for the head, we achieved SAR of 60-380 W/kg in the target leading to a 40 degrees C heat-coverage of 86%. However, the coverage withor =42 degrees C is unsatisfactory at present (30% of the target volume in group A and only 0.2% in group B).Further improvement of the temperature distribution is required by refining the implantation techniques or simply by increasing the amount of nanofluid or elevation of the magnetic field strength. From the actual nanoparticle distribution and derived temperatures we can extrapolate, that already a moderate increase of the H-field by only 2 kA/m would significantly improve the 42 degrees C coverage towards 100% (98%). This illustrates the great potential of the nanofluid-based heating technology.

This prospective study was performed to compare the image quality, tumor delineation, and depiction of staging criteria on MRI of prostate cancer at 1.5 and 3.0 T.Twenty-four patients with prostate cancer underwent MRI at 1.5 T using the combined endorectal-body phased-array coil and at 3.0 T using the torso phased-array coil, among them 22 before undergoing radical prostatectomy. The prostate was imaged with T2-weighted sequences in axial and coronal orientations at both field strengths and, in addition, with an axial T1-weighted sequence at 1.5 T. Preoperative analysis of all MR images taken together was compared with the histologic findings to determine the accuracy of MRI for the local staging of prostate cancer. In a retroanalysis, the image quality, tumor delineation, and conspicuity of staging criteria were determined separately for both field strengths and compared. Statistical analysis was performed using Wilcoxon's and the McNemar tests.In the preoperative analysis, MRI (at both 1.5 and 3.0 T) had an accuracy of 73% for the local staging of prostate cancer. The retroanalysis yielded significantly better results for 1.5-T MRI with the endorectal-body phased-array coil in terms of image quality (p0.001) and tumor delineation (p = 0.012) than for 3.0-T MRI with the torso phased-array coil. Analysis of the individual staging criteria for extracapsular disease did not reveal a superiority of either of the two field strengths in the depiction of any of the criteria.Intraindividual comparison shows that image quality and delineation of prostate cancer at 1.5 T with the use of an endorectal coil in a pelvic phased-array is superior to the higher field strength of 3.0 T with a torso phased-array coil alone. As long as no endorectal coil is available for 3-T imaging, imaging at 1.5 T using the combined endorectal-body phased-array coil will continue to be the gold standard for prostate imaging.

Die vorliegende Arbeit gibt einen Uberblick uber die orbitalen Erkrankungen und deren Erscheinungsbild in der MRT. Die MRT hat sich in den letzten Jahren als bildgebendes Verfahren in der Diagnostik von Orbitaerkrankungen zunehmend etablieren konnen. Fur die Untersuchung steht eine Auswahl unterschiedlicher Oberflachenspulen zur Verfugung. Die Wahl der Spule sollte entsprechend der Fragestellung und der Region erfolgen. Des Weiteren wird auf die Aussagekraft der verschiedenen Sequenzen und der Kontrastmittelgabe eingegangen.

Non-invasive thermometry (NIT) is a valuable and probably indispensable tool for further development of radiofrequency (RF) hyperthermia. A hybridization of an MRI scanner with a hyperthermia system is necessary for a real-time NIT. The selection of the best thermographic method is difficult, because many parameters and attributes have to be considered.In the hybrid system (Siemens Symphony/BSD-2000-3D) the standard methods for NIT were tested such as T1, diffusion (ADC: apparent diffusion coefficient) and proton-resonance-frequency shift (PFS) method. A series of three-dimensional datasets was acquired with different gradient-echo sequences, diffusion-weighted EPI spin-echo sequences and calculated MR-temperatures in the software platform AMIRA-HyperPlan. In particular for the PFS-method, corrective methods were developed and tested with respect to drift and other disturbances. Experiments were performed in phantoms and the results compared with direct temperature measurements. Then the procedures were transferred to clinical applications in patients with larger tumours of the lower extremity or the pelvis.Heating experiments and MR-thermography in a homogeneous cylindrical phantom give an excellent survey over the potentials of the methods. Under clinical conditions all these methods have difficulties due to motion, physiological changes, inhomogeneous composition and susceptibility variations in human tissues. The PFS-method is most stable in patients yielding reasonable MR temperature distributions and time curves for pelvic and lower extremity tumours over realistic treatment times of 60-90 min. Pooled data exist for rectal tumour recurrencies and soft tissue sarcomas. The fat tissue can be used for drift correction in these patients. T1 and diffusion-dependent methods appear less suitable for these patients. The standard methods have different sensitivities with respect to the various error sources. The advantages and pitfalls of every method are discussed with respect to the literature and illustrated by the phantom and patient measurements.MR-controlled RF hyperthermia in a hybrid system is well established in phantoms and already feasible for patients in the pelvic and lower extremity region. Under optimal conditions the temperature accuracy might be in the range of 0.5 degrees C. However a variety of developments, especially sequences and post-processing modules, are still required for the clinical routine.

Purpose: To assess image quality and overall accuracy of magnetic resonance imaging (MRI), including two magnetic cholangiopancreatography (MRCP) techniques, for the diagnostics and preoperative work-up of malignant hilar obstructions. Material and Methods: Thirty-one patients with malignant hilar obstructions (hilar cholangiocarcinoma, n = 30; hepatocellular carcinoma, n = 1) received MRCP by two techniques (single-shot thick-slab and multisection thin-slice MRCP) and unenhanced and contrast material-enhanced MRI. MR assessment included the evaluation of image quality and visualization of bile ducts (5-point scale), and the classification of tumor status. MR results were subsequently correlated with the results from surgery and pathology. Results: The maximum intensity projections of multisection thin-slice MRCP had significantly more artifacts compared to MRCP in the single-shot thick-slab technique, and overall image quality of single-shot thick-slab MRCP was rated significantly superior compared to multisection thin-slice MRCP (4.4±0.7 and 4.1±0.9, respectively). Moreover, ductal visualization of different parts of the biliary system was rated superior with single-shot thick-slab MRCP. In contrast, the original data from multisection thin slice MRCP facilitated visualization of periductal lesions and adjacent structures. Overall MR accuracy for the assessment of tumor status, periductal infiltration, and lymph node metastases was 90%, 87%, and 66%, respectively. Conclusion: For evaluation of malignant hilar obstructions, MRCP by the single-shot thick-slab technique had superior image quality and fewer artifacts; in contrast, besides sole biliary visualization, multisection MRCP depicted complementary adjacent parenchymal and periductal structures. We therefore recommend MRI, with a combination of both MRCP techniques, for the diagnostic work-up and therapy planning of malignant hilar obstructions.

Purpose: To prospectively assess a dose-response relationship for small volumes of liver parenchyma after single-fraction irradiation. Methods and Materials: Twenty-five liver metastases were treated by computed tomography (CT)-guided interstitial brachytherapy. Magnetic resonance imaging was performed 1 day before and 3 days and 6, 12, and 24 weeks after therapy. MR sequences included T1-w gradient echo (GRE) enhanced by hepatocyte-targeted gadobenate dimeglumine. All MRI data sets were merged with 3D dosimetry data and evaluated by two radiologists. The reviewers indicated the border of hyperintensity on T2-w images (edema) or hypointensity on T1-w images (loss of hepatocyte function). Based on the total 3D data, a dose-volume histogram was calculated. We estimated the threshold dose for either edema or function loss as the D 90 , i.e., the dose achieved in at least 90% of the pseudolesion volume. Results: Between 3 days and 6 weeks, the extension of the edema increased significantly from the 12.9 Gy isosurface to 9.9 Gy (standard deviation [SD], 3.3 and 2.6). No significant change was detected between 6 and 12 weeks. After 24 weeks, the edematous tissue had shrunk significantly to 14.7 Gy (SD, 4.2). Three days postbrachytherapy, the D 90 for hepatocyte function loss reached the 14.9 Gy isosurface (SD, 3.9). At 6 weeks, the respective zone had increased significantly to 9.9 Gy (SD, 2.3). After 12 and 24 weeks, the dysfunction volume had decreased significantly to the 11.9 Gy and 15.2 Gy isosurface, respectively (SD, 3 and 4.1). Conclusions: The 95% interval from 7.6 to 12.2 Gy found as the minimal hepatocyte tolerance after 6 weeks accounts for the radiobiologic variations found in CT-guided brachytherapy, including heterogeneous dose rates by variable catheter arrays.

To implement noninvasive thermometry, we installed a hybrid system consisting of a radiofrequency multiantenna applicator (SIGMA-Eye) for deep hyperthermia (BSD-2000/3D) integrated into the gantry of a 1.5 Tesla magnetic resonance (MR) tomograph Symphony. This system can record MR data during radiofrequency heating and is suitable for application and evaluation of methods for MR thermography. In 15 patients with preirradiated pelvic rectal recurrences, we acquired phase data sets (25 slices) every 10 to 15 minutes over the treatment time (60-90 minutes) using gradient echo sequences (echo time = 20 ms), transformed the phase differences to MR temperatures, and fused the color-coded MR-temperature distributions with anatomic T1-weighted MR data sets. We could generate one complete series of MR data sets per patient with satisfactory quality for further analysis. In fat, muscle, water bolus, prostate, bladder, and tumor, we delineated regions of interest (ROI), used the fat ROI for drift correction by transforming these regions to a phase shift zero, and evaluated the MR-temperature frequency distributions. Mean MR temperatures (TMR), maximum TMR, full width half maximum (FWHM), and other descriptors of tumors and normal tissues were noninvasively derived and their dependencies outlined. In 8 of 15 patients, direct temperature measurements in reference points were available. We correlated the tumor MR temperatures with direct measurements, clinical response, and tumor features (volume and location), and found reasonable trends and correlations. Therefore, the mean TMR of the tumor might be useful as a variable to evaluate the quality and effectivity of heat treatments, and consequently as optimization variable. Feasibility of noninvasive MR thermography for regional hyperthermia has been shown and should be further investigated.

Purpose To assess the safety of CT-guided brachytherapy of lung malignancies and to evaluate the initial therapeutic response. Patients and methods Fifteen patients with 30 lung malignancies were included in this prospective phase I trial (metastases, 28; non-small cell lung cancers, 2). Preinterventionally two patients had a vital capacity of 1 values of 192 Ir brachytherapy was performed using three-dimensional CT data that were acquired after percutaneous applicator positioning. All procedures were performed under local anesthesia. A follow-up CT was performed 6 weeks later and every 3 months postintervention. Results The mean diameter of the 30 lung tumors was 2 cm (range, 0.6 to 11 cm; median diameter, 1.5 cm). The minimal dose within the tumor margin was 20 Gy in all 30 tumors treated. Except for nausea in one patient and focal hemorrhage detected on CT in two patients, no acute adverse events were recorded. One patient developed an abscess at the previous tumor location 9 months after treatment, which proved to be a local tumor recurrence. The median follow-up period was 5+ months with a local tumor control of 97%. Conclusion The novel technique of CT-guided interstitial brachytherapy was safe for the treatment of lung tumors and yielded a very low complication rate. The initial data on therapeutic response are promising.

Ultraschallkontrastmittel haben in den letzten Jahren einen hohen Stellenwert in der Lebertumordiagnostik erlangt. Kontrastverstarkter Ultraschall kann zum einen fur die Detektion von Lebertumoren wie bei der Metastasensuche im Rahmen des Tumorstagings und zum anderen fur die Tumorcharakterisierung verwendet werden. Das Anflutungsverhalten des Ultraschallkontrastmittels spielt bei der Charakterisierung eine entscheidende Rolle, die Anreicherungsmuster entsprechen dabei weitgehend den aus der kontrastverstarkten Computertomographie bekannten Mustern. Kontrastverstarkter Ultraschall kann aber auch bei der Therapiekontrolle ablativer Tumortherapien, bei der Visualisierung schwierig darstellbarer Gefase und zur Messung der sog. Lebertransitzeit angewendet werden.

PURPOSE: Inhaled nitric oxide (iNO) is an effective therapy for severe hypoxemia in most patients with acute respiratory distress syndrome (ARDS). For unknown reason, a subset of ARDS patients does not respond favorably to iNO therapy. We hypothesized that radiological manifestation of lung injury may be related to iNO response. MATERIALS AND METHODS: We retrospectively analyzed data from n = 25 ARDS patients who received iNO, and underwent chest CT within 72 h prior to inhaled treatment. The morphology of coherently pathologic lung tissue was characterized by the length of the borderline between consolidated, infiltrated and atelectatic lung tissue and radiologically normal lung tissue. This quantity was expressed as relative fraction of the visceral pleural circumference and averaged over all CT slices. Furthermore we semiquantitatively determined the total volume of consolidated lung tissue as part of the whole lung. RESULTS: In n = 6 non-responders to iNO (DeltaPaO2 10 %), we found significantly less coherently consolidated lung tissue evidenced by an increased relative borderline when compared to iNO non-responders (0.09 +/- 0.02 vs. 0.1 +/- 0.01; P < 0.05). Moreover, there was a moderate and significant correlation between DeltaPaO2 induced by iNO and the relative borderline in all patients studied (R = 0.59; P < 0.05). Total fraction of consolidated lung tissue volume was not different between iNO non-responders and responders (60 +/- 3 % vs. 54 +/- 2 % n. s.). CONCLUSION: Our data demonstrate that the gross morphological distribution of pathological lung tissue influences iNO response in ARDS. Inhaled NO was most beneficial in injured lungs characterized by many small consolidated areas surrounded by normal lung tissue. The increased borderline between pathologic and normal lung tissue offers additional possibility for iNO to divert blood flow from shunt areas to ventilated lung regions, which consequently improves arterial oxygenation.

Ziel: Ziel dieser Arbeit war die Evaluierung der Durchfuhrbarkeit und des potenziellen Nutzens der intraoperativen Computertomographie (IOP-CT) wahrend der videoassistierten Thorakoskopie (VATS) zur Fuhrung thorakoskopischer Eingriffe. Material und Methoden: Bei 15 konsekutiven Patienten mit peripheren intrapulmonalen Rundherden wurde eine VATS mit intraoperativer Computertomographie (IOP-CT) durchgefuhrt. Bei 9/15 Patienten waren multiple (≥ 2) Lasionen bekannt (Gruppe 1), bei weiteren 6/15 Patienten war eine Lasion bekannt (Gruppe 2). Zur IOP-CT wurde das mobile Philips Tomoscan M-System genutzt. Perkutane Markierungen erfolgten intraoperativ durch den anwesenden Radiologen nach erfolgloser Thorakoskopie mittels eines Markierungssets (Somatex, Deutschland). Die VATS wurde unter allgemeiner Anasthesie und Doppel-Lumen-Intubation durchgefuhrt. Intraoperatives CT und praoperative CT wurden nachfolgend zusatzlich hinsichtlich Abbildungsqualitat und Darstellung pulmonaler Rundherde verglichen. Ergebnisse: Die intraoperative CT war in Kombination mit der videoassistierten Thorakoskopie komplikationslos durchfuhrbar. Eine Thorakotomie wurde bei 5/15 Patienten aufgrund einer intraoperativen, CT-gestutzten Markierung vermieden. Bei zwei Patienten konnte die histologische Diagnose erst durch eine CT-gestutzte Biopsie nach Thorakoskopieversuch gestellt werden. Zusammenfassung: Eine Kombination von IOP-CT und VATS stellte sich als komplikationslos durchfuhrbar heraus und fuhrte zu einer Verringerung der Anzahl von offenen Thorakotomien. Intrapulmonale, durch VATS nicht zu detektierende Lasionen konnen unter CT-Steuerung auch intraoperativ markiert und unter Vermeidung einer offenen Thorakotomie thorakoskopisch reseziert werden. Purpose: To evaluate the feasibility and potential use of intraoperative computed tomography (IOP CT) as guidance for video-assisted thoracic surgery (VATS). Material and Methods: Fifteen consecutive patients with peripheral intrapulmonary nodules underwent a thoracoscopy with IOP CT. Solitary lesions were known in 6/15 patients (40 %, group II) whereas 9/15 (60 %, group I) patients had multiple lesions (n ≥ 2). IOP CT was performed with the mobile CT scanner Philips Tomoscan M. Radiologists intraoperatively placed percutaneous marks of lung lesions after unsuccessful VATS by use of a lung marker set (Somatex, Teltow, Germany). VATS was performed under general anaesthesia and with double lumen endotracheal intubation for single lung ventilation. Imaging quality and imaging of pulmonary nodules were rated. Results: IOP CT was evaluated as feasible combined with VATS. Thoracotomy was avoided in 5/15 patients where lesions could not be detected by VATS. A CT-guided biopsy was performed in two patients after an unsuccessful attempt of thoracoscopy. There were no documented side effects. Conclusion: First clinical results suggest that a combination of VATS and IOP CT is feasible. Thus, the number of open thoracoscopies might be decreased. Intrapulmonary lesions not detectable with VATS could be marked under CT - guidance intraoperatively and then resected by thoracoscopy.

Purpose To evaluate the signal-to-noise ratio (SNR), precision, and accuracy of phase-contrast flow measurements at 3 T with the help of an in vitro model and to compare the results with data from two 1.5-T scanners. Materials and Methods Using an identical setup of a laminar flow model and sequence parameters, measurements were done at one 3-T and at two 1.5-T systems. Precision, accuracy, and SNR were obtained for velocity encodings ranging from 55 up to 550 cm−1. SNRs were calculated from the magnitude as well as the flow encoded images. Results Precision and accuracy for the in vitro flow model were similarly high in all scanners with no significant difference. For velocity encodings from 55 cm−1 up to 550 cm−1, the SNR in magnitude as well as phase encoded images of the 3-T measurements was approximately 2.5 times higher than the SNR obtained from the two 1.5-T systems. Conclusion Even without optimization for the 3-T environment, flow measurements show the same high accuracy and precision as is known from clinical 1.5-T scanners. The superior SNR at 3 T will allow further improvements in temporal and spatial resolution. This will be of interest for small-size vessels like coronary arteries or for slow diastolic flow patterns. J. Magn. Reson. Imaging 2005;21:604–610. © 2005 Wiley-Liss, Inc.

The aim of this study was to compare CT, MRI and FDG-PET in the prediction of outcome of neoadjuvant radiochemotherapy in patients with locally advanced primary rectal cancer. A total of 23 patients with T3/4 rectal cancer underwent a preoperative radiochemotherapy combined with regional hyperthermia. Staging was performed using four-slice CT (n=23), 1.5-T MRI (n=10), and (18)F-FDG-PET (n=23) before and 2-4 weeks after completion of neoadjuvant treatment. Response criteria were a change in T category and tumour volume for CT and MRI and a change in glucose uptake (standard uptake value) within the tumour for FDG-PET. Imaging results were compared with those of pretherapy endorectal ultrasound and histopathological findings. Histopathology showed a response to neoadjuvant therapy in 13 patients whereas 10 patients were classified as nonresponders. The mean SUV reduction in responders (60+/-14%) was significantly higher than in nonresponders (37+/-31%; P=0.030). The sensitivity and specificity of FDG-PET in identifying response was 100% (CT 54%, MRI 71%) and 60% (CT 80%, MRT 67%). Positive and negative predictive values were 77% (CT 78%, MRI 83%) and 100% (CT 57%, MRI 50%) (PET P=0.002, CT P=0.197, MRI P=0.500). These results suggest that FDG-PET is superior to CT and MRI in predicting response to preoperative multimodal treatment of locally advanced primary rectal cancer.

This study compared different magnetic resonance imaging (MRI) methods with Tl(201) single photon emission computerized tomography (SPECT) and the "gold standard" for viability assessment, functional recovery after coronary artery bypass grafting (CABG). Twenty patients (64+/-7.3 years) with severely impaired left ventricular function (ejection fraction [EF] 28.6+/-8.7%) underwent MRI and SPECT before and 6 months after CABG. Wall-motion abnormalities were assessed by stress cine MRI using low-dose dobutamine. A segment with a nonreversible defect in Tl(201)-SPECT and a delayed enhancement (DE) in an area50% of the entire segment, as well as an end-diastolic wall thickness6 mm, was defined as nonviable. The mean postoperative EF (n=20) improved slightly from 28.6+/-8.7% to 32.2+/-12.4% (not significant). Using the Tl(201)-SPECT as the reference method, end-diastolic wall thickness, MRI-DE, and stress MRI showed high sensitivity of 94%, 93%, and 84%, respectively, but low specificities. Using the recovery of contractile function 6 months after CABG as the gold standard, MRI-DE showed an even higher sensitivity of 99%, end-diastolic wall thickness 96%, stress MRI 88%, and Tl(201)-SPECT 86%. MRI-DE showed advantages compared with the widely used Tl(201)-SPECT and all other MRI methods for predicting myocardial recovery after CABG.

A magnetic resonance (MR)-compatible three-dimensional (3-D) hyperthermia applicator was developed and evaluated in the magnetic resonance (MR) tomograph Siemens MAGNETOM Symphony 1.5 T. Radiating elements of this applicator are 12 so-called water coated antenna (WACOA) modules, which are designed as specially shaped and adjustable dipole structures in hermetically closed cassettes that are filled by deionized water. The WACOA modules are arranged in the applicator frame in two transversal antenna subarrays, six antennas per subarray. As a standard load for the applicator an inhomogeneous phantom was fabricated. Details of applicator's realization are presented and a 3-D comparison of calculated and measured temperature data sets is made. A fair agreement is achieved that demonstrates the numerically supported applicator's ability of phase-defined 3-D pattern steering. Further refinement of numerical models and measuring methods is necessary. The applicator's design and the E-field calculations were performed using the finite-difference time-domain (FDTD) method. The calculation and optimization of temperature patterns was obtained using the finite element method (FEM). For MR temperature measurements the proton resonance frequency (PRF) method was used.

Purpose To present first results of radiofrequency ablation of liver tumors using a new MR compatible applicator. Materials and methods We performed 37 interventions in 20 patients (mean age 58.6 years) with primary intrahepatic malignancies or metastases: colorectal carcinoma n = 6, hepatocellular carcinoma n = 3, pancreatic carcinoma n = 4, sarcoma n = 2, cholangiocellular carcinoma n = 1, carcinoma of the tonsil n = 1, breast carcinoma n = 1, gastric carcinoma n = 1, and gastrointestinal stroma tumor n = 1. Interventions were performed under CT-guidance with CT fluoroscopy (n = 32) and under MR-guidance (n = 5) using fast T1-weighted sequences in breath-hold technique. RFA was performed with the RF-generator (150 W) under local anesthesia and sedation using MR compatible applicators (Starburst XL, Rita Medical Systems, USA) together with the appropriate Soft Tissue Introducer System. Intra-interventional control was performed with intrahepatically or intralesionally placed introducer system or applicator. MRI was performed with plain breath-triggered T2-weighted turbo spin echo sequences (TSE T2) with fat saturation. Results All interventions were performed without major events. The mean diameter of induced coagulation was 4.0 (+/- 0.7) cm. Repositioning was necessary in 8 interventions (21 %) after detection of residual tumor on an intra-interventional MRI. After a mean follow-up of 6.5 (+/- 1.2) months, the local tumor control rate was 92 %. Conclusion MR-compatible RF applicators offer the opportunity for intra-interventional detection of residual tumor during RF ablations by use of sensitive MRI sequences. These procedures may lead to a higher confidence in tumour ablation and may reduce the number of re-interventions and local recurrences of intrahepatic tumors.