Search

Experimental watersheds have a long tradition as research sites in hydrology and have been used since the late nineteenth and early twentieth centuries. The University of Natural Resources and Life Sciences Vienna (BOKU) recently extended its experimental research forest site “Rosalia” with an area of 950 ha towards the creation of a full ecological-hydrological experimental watershed. The overall objective is to implement a multi-scale, multi-disciplinary observation system that facilitates the study of water, energy and solute transport processes in the soil–plant–atmosphere continuum. This article describes the characteristics of the site and the monitoring network and its instrumentation that has been installed since 2015, as well as the datasets. The network includes four discharge gauging stations and seven rain gauges along with observations of air and water temperature, relative humidity, and electrical conductivity. In four profiles, soil water content and temperature are recorded at different depths. In addition, since 2018, nitrate, TOC and turbidity have been monitored at one gauging station. In 2019, a programme to collect isotopic data in precipitation and discharge was initiated. All data collected since 2015, including, in total, 56 high-resolution time series (with 10 min sampling intervals), are provided to the scientific community on a publicly accessible repository. The datasets are available at https://doi.org/10.5281/zenodo.3997140 (Fürst et al., 2020).

Purpose: For people with hearing implants (HI), magnetic resonance imaging (MRI) still presents some difficulties due to the built-in magnet. Radiologists often have concerns regarding complications associated with HIs. The aim of this study was to record the experiences of HI users during and after MRI examinations., Method: A survey including 15 questions regarding MRI specifics, namely changes in hearing ability, hearing/sound impressions, pain, uncomfortable feelings, etc., were mailed to our patients., Results: Overall, 79 patients with HI had a total of 159 MR examinations in our institute. A total of 45 HI recipients reported back: 35% stated that they had been rejected by an MRI Institute because of their HI. Their feelings/impression ratings during the measurements were not present and therefore were not rated for the majority (49%), 42% of the HI users rated the pain with 0 (no pain), 2% with 1 (very light pain), 4% with 5 (acceptable pain), and 2% rated the pain with 7, which is between acceptable and strong pain. One examination resulted in a dislocation of the magnet of a cochlear implant (CI 512 Cochlear Limited). No adverse events were reported for MED-EL HI users in the survey (none of the contacted AB users answered the questionnaire). The reported mean daily wearing time was 11.6 ± 4.6 h per day for 6.3 ± 1.7 days per week., Conclusions: Based on these results and our experience we conclude that MRI examinations with HI are safe given that the measurements are performed according to the safety policies and procedures released by the manufacturers.

Perioperative stroke is a devastating complication after coronary artery bypass graft (CABG) surgery, with atherosclerosis of the ascending aorta as important risk factor. During surgical manipulation, detachment of plaques can lead to consecutive embolization into brain-supplying arteries. High-pitch computed tomography angiography (HP-CTA) represents a non-invasive imaging modality, which provides the opportunity for comprehensive imaging of the ascending aorta, including plaque detection and advanced characterization. In our present retrospective study on 719 individuals, who had undergone HP-CTA within 6 months prior to CABG, atherosclerotic disease of the ascending aorta was evaluated with respect to perioperative stroke rates. For image analysis, the ascending aorta was divided into a proximal and distal part, consisting of four segments, and evaluated for presence and distribution of calcified and mixed plaques. All patients with perioperative stroke presented with atherosclerotic disease of the ascending aorta. The stroke rate was significantly associated with the presence and extent of atherosclerotic disease. Patients burdened with mixed plaques presented with significantly higher perioperative stroke rates. This study demonstrates that HP-CTA allows accurate evaluation of plaque extent and composition in the ascending aorta, and therefore may improve risk stratification of stroke prior to CABG.

Objectives: The aim of this study was to determine stroke rates in patients who did or did not undergo routine computed tomography angiography (CTA) aortic imaging before isolated coronary artery bypass grafting (CABG)., Methods: We conducted a retrospective analysis of a prospectively maintained single-centre registry. Between 2009 and 2016, a total of 2320 consecutive patients who underwent isolated CABG at our institution were identified. Propensity score matching was used to create a paired cohort of patients with similar baseline characteristics who did (CTA cohort) or did not (non-CTA cohort) undergo preoperative aortic CTA. The primary end point of the analysis was in-hospital stroke., Results: In 435 propensity score-matched pairs, stroke occurred in 4 patients (0.92%) in the CTA cohort and in 14 patients (3.22%) in the non-CTA cohort (P = 0.017). Routine preoperative aortic CTA was associated with a significantly reduced risk of in-hospital stroke [relative risk 0.29, 95% confidence interval (CI) 0.09-0.86; P = 0.026; absolute risk reduction 2.3%, 95% CI 0.4-4.2; P = 0.017; number needed to treat = 44, 95% CI 24-242]., Conclusions: A preoperative screening for atheromatous aortic disease using CTA is associated with reduced risk of stroke after CABG. The routine use of preoperative aortic CTA could be applied so that surgical manipulation of the ascending aorta can be selectively reduced or avoided in patients with atheromatous aortic disease., (© The Author(s) 2019. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.)

Background and Purpose- The recent Save ChildS study provides multicenter evidence for the use of mechanical thrombectomy in children with large vessel occlusion arterial ischemic stroke. However, device selection for thrombectomy may influence rates of recanalization, complications, and neurological outcomes, especially in pediatric patients of different ages. We, therefore, performed additional analyses of the Save ChildS data to investigate a possible association of different thrombectomy techniques and devices with angiographic and clinical outcome parameters. Methods- The Save ChildS cohort study (January 2000-December 2018) analyzed data from 27 European and United States stroke centers and included all pediatric patients (<18 years), diagnosed with arterial ischemic stroke who underwent endovascular recanalization. Patients were grouped into first-line contact aspiration (A Direct Aspiration First Pass Technique [ADAPT]) and non-ADAPT groups as well as different stent retriever size groups. Associations with baseline characteristics, recanalization rates (modified Treatment in Cerebral Infarction), complication rates, and neurological outcome parameters (Pediatric National Institutes of Health Stroke Scale after 24 hours and 7 days; modified Rankin Scale and Pediatric Stroke Outcome Measure at discharge, after 6 and 24 months) were investigated. Results- Seventy-three patients with a median age of 11.3 years were included. Currently available stent retrievers were used in 59 patients (80.8%), of which 4×20 mm (width×length) was the most frequently chosen size (36 patients =61%). A first-line ADAPT approach was used in 7 patients (9.6%), and 7 patients (9.6%) were treated with first-generation thrombectomy devices. In this study, a first-line ADAPT approach was neither associated with the rate of successful recanalization (ADAPT 85.7% versus 87.5% No ADAPT) nor with the complication rate or the neurological outcome. Moreover, there were no associations of stent retriever sizes with rates of recanalization, complication rates, or outcome parameters. Conclusions- Our study suggests that neurological outcomes are generally good regardless of any specific device selection and suggests that it is important to offer thrombectomy in eligible children regardless of technique or device selection. Registration- URL: https://www.drks.de/; Unique identifier: DRKS00016528.

Rationale and Objectives: Hybrid positron emission tomography-magnetic resonance (PET-MR) is a novel imaging technology that enables a comprehensive assessment of myocardial viability. The aim of this study was to intra-individually compare simultaneously acquired viability parameters from MRI and PET to determine complementary and redundant information., Materials and Methods: Thirty-nine patients with ischemic heart disease (IHD) underwent cardiac PET-MR for myocardial viability assessment. Cardiac magnetic resonance (CMR), including late gadolinium enhancement (LGE), and PET, including a dynamic dual-tracer acquisition of [ 13 N]ammonia ([ 13 N]NH 3 )/[ 18 F]fluorodeoxyglucose ([ 18 F]FDG), were performed simultaneously. Allocation, extent, and transmural degree of left ventricular (LV) scars were measured from LGE. Perfusion, viability, and hibernation were assessed by PET., Results: A comparison of scar location revealed six more areas of infarction on MR than on PET. Mean LV scarring by CMR was 14% (range, 2% to 42%) and 14% (range, 1% to 46%) by PET (CMR vs. PET: p = 0.9). An intra-individual comparison of scarring showed a good inter-method correlation (r = 0.7), which was also evident in the subgroup with low ejection fraction (EF) (r = 0.6). Hibernation and transmural degree of scars showed a moderate to weak correlation (r = 0.4), which was even worse in the low EF group (r = 0.1)., Conclusions: In patients with IHD, there was a good correlation between PET and CMR for the LV scar extent using hybrid cardiac PET-MR. The degree of transmural scarring by CMR showed no correlation to PET hibernation. Therefore, cardiac PET-MR might be a suitable tool for a comprehensive assessment of myocardial viability if used to predict response to cardiac reperfusion strategies., (Copyright © 2019. Published by Elsevier Inc.)

Objectives: To evaluate the influence of baseline clinical and morphological parameters on the occurrence of a late stent graft related endoleak (srEL; types 1 and 3) after endovascular aneurysm repair (EVAR)., Methods: This is a retrospective case control study of patients who were routinely followed up after EVAR of abdominal aortic aneurysms. Pre-interventional, pre-discharge, and last available multislice computed tomography angiogram (MSCTA) of 279 patients were analysed. Stent graft related endoleaks detected by follow up MSCTA at least six months after EVAR were specified as late srEL. Baseline demographic characteristics and morphological variables were derived from the pre-interventional and pre-discharge MSCTA. Univariable and multivariable analysis with a Cox proportional hazards model were used to determine baseline factors associated with the occurrence of a late srEL., Results: Twenty-four (8.6%) of 279 patients suffered a late srEL, during a mean MSCTA follow up of 30.9 ± 25.8 (23.5, IQR 10.6-42.8) months. In the univariable analysis, age (hazard ratio [HR] 1.09; p = .001), female sex (HR 3.25; p = .014), right iliac sealing diameter (HR 10.04; p = .03), left iliac sealing diameter (HR 8.65; p = .001), infrarenal aortic neck angulation (HR 1.02; p = .011), and suprarenal fixation level (HR 3.47; p = .014) were significantly associated with an increased incidence of late srEL. Age (HR 1.08; p = .012), female sex (HR 2.72; p = .049), and left iliac sealing diameter (HR 4.48; p = .033) proved to be risk factors significantly associated with a higher incidence of late srEL in multivariable analysis., Conclusions: Older patients, those with female gender, and those with larger left iliac sealing diameters seem to experience higher rates of late srEL. Independent confirmation of these must be addressed in larger studies., (Copyright © 2018 European Society for Vascular Surgery. Published by Elsevier B.V. All rights reserved.)

Objective: This study retrospectively assessed in-hospital mortality and long-term results of emergency thoracic endovascular aortic repair (TEVAR) for patients with life-threatening acute complicated type B aortic dissection (acTBD)., Methods: Between March 2001 and December 2016, there were 55 patients (40 male; median age, 52 ± 13 years) with an acTBD who were treated with TEVAR for malperfusion (58%), aortic rupture (18%), or persistent untreatable pain with true lumen reduction or rapid aortic diameter enlargement (24%) as a sign of disease progression. The patients were categorized according to clinical appearance into two groups: group A, malperfusion, pending rupture, or rupture; and group B, persistent ongoing pain, rapid enlargement of aortic diameter, or significant changes in the true to false lumen ratio. Four patients (7%) had undergone previous aortic surgery., Results: Technical success (coverage of the primary intimal tear) was achieved in 50 patients (91%). The overall in-hospital mortality rate was 9% (n = 5), and there was a statistically significant difference in early mortality between group A and group B (7% vs 2%; P < .02). Causes of in-hospital death were all aorta related, including a rupture during the procedure and on the first postinterventional day in two patients and redissection (ascending aorta, n = 2; descending aorta, n = 1) with a consequent aortic rupture after TEVAR in the remaining three. Permanent neurologic dysfunction occurred in five patients (stroke, n = 2; paraplegia, n = 3). Overall, 19 patients (34%) developed early endoleaks (type IA, n = 5; type IB, n = 11; type II, n = 2; type IB plus type II, n = 1). Therefore, 5 patients needed early (within 30 days) endovascular intervention because of a type IA (n = 2), type IB (n = 3), or type II endoleak (n = 1) and the rapid progression of aortic diameter, persistent signs of ischemia (n = 2), or rupture (n = 1), whereas the remaining 14 patients were treated conservatively and followed up by computed tomography angiography. Seven patients with early endoleaks needed an endovascular intervention (n = 3) or conventional surgery (n = 4) because of aortic progression in the follow-up period (mean interval after procedure, 92 ± 56 months). The actual survival rates were 87%, 85%, and 75% at 1 year, 2 years, and 5 years, respectively, and freedom from aorta-related death was 87%, 87%, and 77% at 1 year, 2 years, and 5 years, respectively. Freedom from reintervention for any cause using a Kaplan-Meier analysis was 70%, 68%, 68%, and 63% at 6 months, 1 year, 2 years, and 5 years, respectively., Conclusions: TEVAR of acTBD has been proven to be an excellent treatment modality in this cohort of high-risk patients, with promising midterm and long-term results., (Copyright © 2018 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.)

Rationale and Objectives: This study aimed to determine the diagnostic utility of standardized uptake values (SUV) and apparent diffusion coefficients (ADC) for assessment of focal and diffuse bone marrow involvement in patients with malignant lymphoma., Materials and Methods: Sixty treatment-naive patients (28 males; mean age 51.2 ± 16.7 years) with histologically proven lymphoma, who underwent fludeoxyglucose ( 18 F) positron emission tomography-computed tomography ([F18]-FDG-PET/CT) and whole-body diffusion-weighted imaging (WB-DWI) within 7 days, and also routine bone marrow biopsy, were included in this institutional review board-approved, retrospective study. The maximum SUV (SUVmax) on [F18]-FDG-PET/CT, and the mean ADC (ADCmean, ×10 -3 mm 2 /s) on whole-body-DWI, were extracted from focal lesions, or, in their absence, from the thoracic (Th8) and lumbar vertebral bodies (L4), the sacral bone (S1), and the iliac crest. Lesion-to-liver-ratios (SUVmax-ratio) were calculated. Pearson correlation coefficients were used to assess the correlation between SUVmax-ratios and ADCmean values., Results: Bone marrow involvement was observed in 16 of 60 patients (8 of 16 with diffuse infiltration). The SUVmax-ratio cutoff value was 95.25% for focal and 70.2% for diffuse bone marrow involvement (sensitivity/specificity of 87.5%/86.4% and 100%/43.2%, respectively). The ADCmean cutoff value was 0.498 for focal and 0.401 for diffuse bone marrow involvement (sensitivity/specificity of 100%/90.9% and 87.5%/56.8%, respectively). No significant correlations were found between SUVmax-ratios and ADCmean values in the different groups., Conclusion: With the liver as reference tissue, quantitative [F18]-FDG-PET/CT may be useful to differentiate bone marrow involvement from normal bone marrow in patients with lymphoma, even though the specificity for diffuse marrow involvement is rather low. Quantitative DWI can be used only to distinguish focal bone marrow lesions from normal bone marrow., (Copyright © 2018 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.)

The purpose of our study was to determine the value of different hybrid imaging combinations for the detection of focal and diffuse bone marrow infiltration in lymphoma. Patients with histologically proven lymphoma, who underwent both [18F]-FDG-PET/CT and whole-body MRI (including T1- and diffusion-weighted [DWI] sequences) within seven days, and a subsequent bone marrow biopsy, were retrospectively included. Three hybrid imaging combinations were evaluated: (1) [18F]-FDG-PET/CT; (2) [18F]-FDG-PET/T1; and (3) [18F]-FDG-PET/DWI. The presence of focal or diffuse bone marrow infiltration was assessed by two rater teams. Sensitivity, specificity, and accuracy for the detection of overall, focal, and diffuse bone marrow involvement were compared between the three hybrid imaging combinations. Overall, lymphomatous bone marrow involvement was found in 16/60 patients (focal, 8; diffuse, 8). Overall sensitivity, specificity, and accuracy were 81.3%, 95.5%, and 91.7% for [18F]-FDG-PET/CT; 81.3%, 97.7%, and 93.3% for [18F]-FDG-PET/T1; and 81.3%, 95.5%, and 91.7% for [18F]-FDG-PET/DWI. No statistically significant differences between the three imaging combinations were observed, based on overall bone marrow involvement, focal involvement, or diffuse involvement. The sensitivity of all three imaging combinations for detecting diffuse bone marrow involvement was only moderate (62.5% for all three combinations). Although the combination of [18F]-FDG-PET and T1-weighted MRI generally showed the best diagnostic performance for the detection of bone marrow involvement in lymphoma, it was not significantly superior to the two other hybrid imaging combinations. Since the sensitivity of all imaging combinations for the detection of diffuse bone marrow involvement was only moderate, bone marrow biopsy cannot be replaced by imaging as yet., Competing Interests: The authors have declared that no competing interests exist.

Purpose: To define the diagnostic precision of non-specialized readers in the detection of type 2 endoleaks (T2EL) in arterial versus venous phase acquisitions, and to evaluate an approach for radiation dose reduction., Methods: The pre-discharge and final follow-up multi-slice CT angiographies of 167 patients were retrospectively analyzed. Image data were separated into an arterial and a venous phase reading set. Two radiology residents assessed the reading sets for the presence of a T2EL, feeding vessels, and aneurysm sac size. Findings were compared with a standard of reference established by two experts in interventional radiology. The effective dose was calculated., Results: Overall, experts detected 131 T2ELs, and 331 feeding vessels in 334 examinations. Persistent T2ELs causing aneurysm sac growth > 5 mm were detected in 20 patients. Radiation in arterial and venous phases contributed to a mean of 58.6% and 39.0% of the total effective dose. Findings of reader 1 and 2 showed comparable sensitivities in arterial sets of 80.9 versus 85.5 (p = 0.09), and in venous sets of 73.3 versus 79.4 (p = 0.15), respectively. Reader 1 and 2 achieved a significant higher detection rate of feeding vessels with arterial compared to venous set (p = 0.04, p < 0.01). Both readers correctly identified T2ELs with growing aneurysm sac in all cases, independent of the acquisition phase., Conclusion: Arterial acquisitions enable non-specialized readers an accurate detection of T2ELs, and a significant better identification of feeding vessels. Based on our results, it seems reasonable to eliminate venous phase acquisitions.

Objectives: The aim was to compare multidirectional stent graft movement in patients with and without a type 2 endoleak., Methods: This was a retrospective case control study of patients being followed up after elective endovascular aneurysm repair of abdominal aortic aneurysms. The post-procedural and final follow up multislice computed tomography (MSCT) of 69 patients with and 74 without a type 2 endoleak were analyzed. Three dimensional (3D) surface models of the stent graft, delimited by landmarks using custom built software, were derived from these MSCT data. The stent graft was segmented in different zones, and the proportion of the total stent graft surface moving >9 mm between the post-procedural and the final follow up MSCT was calculated, given in percentages, and compared between groups. Changes of infrarenal neck, renal artery to stent graft distance, and freedom from stent graft related endoleaks were evaluated., Results: Overall surface movement was higher in the no endoleak (18.8%, IQR 0.1-45.1%) than in the type 2 endoleak group (5.3%, IQR 0-29.7%; p = .06). Furthermore, significantly higher surface movement in the no endoleak group was found in the proximal anchoring zone (p = .04) and the distal left limb (p = .01), which was the modular limb in 81.1% (p < .01). Neck diameter increase (1.0 mm, IQR 0-3.0 mm; p < .01) and renal artery to stent graft distance difference (0 mm, IQR 0-3.3 mm; p < .01) were significantly higher in the no endoleak group. Five patients in the no endoleak and one patient in the type 2 endoleak group suffered from a stent graft related endoleak (p = .27)., Conclusions: The presence of a type 2 endoleak is associated with decreased surface movement of the proximal anchoring zone and the distal modular limb of bifurcated stent grafts., (Copyright © 2015 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.)

Background: Due to preferential implantation of bifurcated devices during endovascular repair of infrarenal abdominal aortic aneurysms (AAA), longer-term results following aortouni-iliac (AUI) endografting are scarce. The aim of this study was to determine the rate of endoleaks as well as frequency of secondary correction procedures after elective and emergent AUI endografting., Methods: A prospectively gathered database at a tertiary care university hospital was retrospectively reviewed from January 2000 until January 2012. This interrogation identified 61 patients who had undergone AUI endografting to treat their AAA. Data retrieval obtained 47 patients with elective AAA repairs while 14 patients received emergent AUI endografting in case of rupture. Procedural outcomes, endoleaks, complications, and secondary interventions during mid-term follow-up were recorded for analysis., Results: Fifty-five patients of the study cohort were male (90.2%) and mean age was 76.5 years (median: 77.2, Q1-Q3: 72.1-81.6). Patient demographics, comorbidities, procedural characteristics, as well as median follow-up length (39.8 months versus 34.9 months) were similar between groups. Endoleaks, complications, and rate of secondary correction procedures were not increased following emergent AUI endografting. The majority of these interventions comprised catheter-based or less invasive surgical procedures. All patients requiring major surgery (three open surgical conversions with endograft explantation and one open aortic banding) survived, while one patient sustained fatal myocardial infarction after a transluminal correction procedure., Conclusion: Emergent AUI endografting was not associated with higher rates of adverse events or correction procedures during mid-term follow-up. Secondary interventions to maintain aneurysm exclusion could be carried out with low mortality., (Copyright © 2015 IJS Publishing Group Limited. Published by Elsevier Ltd. All rights reserved.)

Objective: To prospectively evaluate image quality and radiation dose using a low-dose computed tomography angiography protocol and iterative image reconstruction for high-pitch dual-source CT-angiography (DSCTA) of the supraaortic arteries., Material and Methods: DSCTA was performed in 42 patients, using either 120 kVp tube voltage, 120 mAS tube current, 2.4 pitch and filtered back projection, or 100 kVp tube voltage, 100 mAs tube current, 3.2 pitch, and sinogram affirmed iterative reconstruction. Measurements of vessel attenuation, of the contrast-to-noise ratio (CNR) and the signal-to-noise ratio (SNR) were performed to objectively evaluate image quality. Two readers evaluated subjective image quality and image noise, using a four-point scale. Effective dose was used to compare the differences in radiation dose., Results: Low-dose protocol application showed significantly higher vessel opacification (p = 0.013), and non-significantly higher CNR and SNR values. There was no difference in the subjective image quality and image noise reading between the protocols. Effective dose was significantly lower using the low-dose protocol (1.29 ± 0.21 mSv vs. 2.92 ± 0.72 mSv; p < 0.001)., Conclusion: The combined use of reduced tube voltage, reduced tube current, and iterative reconstruction reduces radiation dose by 55.4% in high-pitch DSCTA of the supraaortic arteries without impairment of image quality.