The aim of the study was to determine whether automated quantification of pulmonary perfused blood volume (PBV) in dual-energy computed tomography pulmonary angiography (DE-CTPA) can be used to ...assess the severity of chronic thromboembolic pulmonary hypertension (CTEPH).
Automated quantification of PBV was performed in 25 consecutive CTEPH patients undergoing DE-CTPA. PBV values were correlated with cardiac index and pulmonary vascular resistance quantified by right heart catheterization and walking distance in the 6-minute walk test using Pearson's correlation coefficient and multivariate linear regression analysis to control for age and gender.
DE-CTPA derived PBV values inversely correlated with systolic (r = -0.64, p = 0.001) and mean (r = -0.57, p = 0.004) pulmonary arterial pressure. There was a trend for PBV values to inversely correlate with pulmonary vascular resistance (r = -0.20, p = 0.35). No significant correlation was found between PBV values and cardiac index or 6-minute walking distance. These correlations were confirmed to be independent of age and gender on multivariate linear regression analysis.
DE-CTPA can be used for an automated quantification of pulmonary PBV in chronic thromboembolic pulmonary hypertension. PBV values correlate inversely with systolic and mean pulmonary arterial pressure and can thus be used to estimate the severity of pulmonary hypertension in these patients. Citation Format: • Meinel FG, Graef A, Thierfelder KM et al. Automated Quantification of Pulmonary Perfused Blood Volume by Dual-Energy CTPA in Chronic Thromboembolic Pulmonary Hypertension. Fortschr Röntgenstr 2014; 186: 151 - 156.
Objectives
To evaluate the diagnostic accuracy of multidetector CT (MDCT) for detection of lumbar disc herniation with MRI as standard of reference.
Methods
Patients with low back pain underwent ...indicated MDCT (128-row MDCT, helical pitch), 60 patients with iterative reconstruction (IR) and 67 patients with filtered back projection (FBP). Lumbar spine MRI (1.5 T) was performed within 1 month. Signal-to-noise ratios (SNR) of cerebrospinal fluid (CSF), annulus fibrosus (AF) and the spinal cord (SC) were determined for all modalities. Two readers independently rated image quality (IQ), diagnostic confidence and accuracy in the diagnosis of lumbar disc herniation using MRI as standard of reference. Inter-reader correlation was assessed with weighted κ.
Results
Sensitivity, specificity, precision and accuracy of MDCT for disc protrusion were 98.8%, 96.5%, 97.1%, 97.8% (disc level), 97.7%, 92.9%, 98.6%, 96.9% (patient level). SNR of IR was significantly higher than FBP. IQ was significantly better in IR owing to visually reduced noise and improved delineation of the discs. κ (>0.90) was excellent for both algorithms.
Conclusion
MDCT of the lumbar spine yields high diagnostic accuracy for detection of lumbar disc herniation. IR improves image quality so that the provided diagnostic accuracy is principally equivalent to MRI.
Key Points
•
MDCT is an accurate alternative to MRI in disc herniation diagnosis
.
•
By IR enhanced image quality improves MDCT diagnostic confidence similar to MRI
.
•
Advances in CT technology contribute to improved diagnostic performance in lumbar spine imaging
.
Collateral blood flow is an important prognostic marker in the acute stroke situation but approaches for assessment vary widely. Our aim was to compare strategies of collateral blood flow assessment ...in dynamic and conventional CTA in their ability to predict the follow-up infarction volume.
We retrospectively included all patients with an M1 occlusion from an existing cohort of 1912 consecutive patients who underwent initial multimodal stroke CT and follow-up MR imaging or nonenhanced CT. Collateralization was assessed in both conventional CT angiography and dynamic CT angiography by using 3 different collateral grading scores and segmentation of the volume of hypoattenuation. Arterial, arteriovenous, and venous phases were reconstructed for dynamic CT angiography, and all collateral scores and the volume of hypoattenuation were individually assessed for all phases. Different grading systems were compared by using the Bayesian information criterion calculated for multivariate regression analyses (Bayesian information criterion difference = 2-6, "positive"; Bayesian information criterion difference = 6-10, "strong"; Bayesian information criterion difference = >10, "very strong").
One hundred thirty-six patients (mean age, 70.4 years; male sex, 41.2%) were included. In the multivariate analysis, models containing the volume of hypoattenuation showed a significantly better model fit than models containing any of the 3 collateral grading scores in conventional CT angiography (Bayesian information criterion difference = >10) and dynamic CT angiography (Bayesian information criterion difference = >10). All grading systems showed the best model fit in the arteriovenous phase. For the volume of hypoattenuation, model fit was significantly higher for models containing the volume of hypoattenuation as assessed in the arteriovenous phase of dynamic CT angiography compared with the venous phase (Bayesian information criterion difference = 6.2) and the arterial phase of dynamic CT angiography (Bayesian information criterion difference = >10) and in comparison with conventional CT angiography (Bayesian information criterion difference = >10).
The use of dynamic CT angiography within the arteriovenous phase by using quantification of the volume of hypoattenuation is the superior technique for assessment of collateralization among the tested approaches.
The selection of patients for endovascular therapy is an important issue in stroke imaging. The aim of this study was to determine the predictive value of 3 different dynamic CT angiography ...parameters, occlusion length, collateralization extent, and time delay to maximum enhancement, for latest generation of stent retriever thrombectomy recanalization outcomes in patients with acute ischemic stroke.
In this study, subjects were selected from an initial cohort of 2059 consecutive patients who had undergone multiparametric CT, including whole-brain CT perfusion. We included all patients with a complete occlusion of the M1 segment of the MCA or the carotid T and subsequent intra-arterial stent retriever thrombectomy. Dynamic CT angiography was reconstructed from whole-brain CT perfusion raw datasets. Angiographic outcome was scored by using the modified TICI scale; and clinical outcome, by using the modified Rankin Scale. Logistic regression analyses were performed to determine independent predictors of a favorable angiographic (mTICI = 3) and clinical outcome (mRS ≤2).
Sixty-nine patients (mean age, 68 ± 14 years; 46% men) were included for statistical analysis. In the regression analysis, a short occlusion length was an independent predictor of favorable angiographic outcome (OR, 0.41; P < .05). Both collateralization grade (OR, 1.00; P > .05) and time delay to peak enhancement (OR, 0.90; P > .05) failed to predict a favorable angiographic outcome. None of the dynamic CT angiography predictors were significantly associated with clinical outcome on discharge (OR, 0.664-1.011; P = .330-.953) or at 90 days (OR, 0.779-1.016; P = .130-.845).
A short occlusion length as determined by dynamic CT angiography is an independent predictor of a favorable angiographic outcome of stent retriever thrombectomy in patients with ischemic stroke.
Purpose
To evaluate feasibility of automatic software-based path proposals for CT-guided percutaneous biopsies.
Methods
Thirty-three patients (60
±
12 years) referred for CT-guided biopsy of focal ...liver lesions were consecutively included. Pre-interventional CT and dedicated software (FraunhoferMeVis Pathfinder) were used for (semi)automatic segmentation of relevant structures. The software subsequently generated three path proposals in downward quality for CT-guided biopsy. Proposed needle paths were compared with consensus proposal of two experts (comparable, less suitable, not feasible). In case of comparable results, equivalent approach to software-based path proposal was used. Quality of segmentation process was evaluated (Likert scale, 1
=
best, 6
=
worst), and time for processing was registered.
Results
All biopsies were performed successfully without complications. In 91 % one of the three automatic path proposals was rated comparable to experts’ proposal. None of the first proposals was rated not feasible, and 76 % were rated comparable to the experts’ proposal. 7 % automatic path proposals were rated not feasible, all being second choice (
n
=
1
) or third choice (
n
=
6
). In 79 %, segmentation at least was good. Average total time for establishing automatic path proposal was 42
±
9 s.
Conclusion
Automatic software-based path proposal for CT-guided liver biopsies in the majority provides path proposals that are easy to establish and comparable to experts’ insertion trajectories.
My friend Bill Thierfelder, a great leader and motivator, puts the words and descriptions to what we leaders try to do every day to challenge ourselves and our teams to be at our best, all the time. ...-Coach Mike Krzyzewski, from the Foreword Dr. Bill Thierfelder knows what it takes to win. As a student at the University of Maryland he dominated the high jump, winning fame as an All-American and Irish national champion. Later he earned his doctorate in sports psychology. He became a private coach and mentor to the world's top athletes...and revealed to them his hard won secrets for success. In Less Than a Minute to Go: The Secret to World-class Performance in Sport, Business and Everyday Life, Thierfelder, now President of Belmont Abbey College, reveals the secrets to: * Becoming a world-class performer * Preparing your mind to win * Making peak performance a common occurrence * Playing with a passion that never ends But Thierfelder does more than give peak performance techniques. In these pages he shows why sports are worthy of our deep attention and effort, whether as athletes or as avid spectators and fans. He shows how sports can and should engage the highest parts of our nature that, in fact, only when we are so engaged can we truly excel. And he reveals how sports train and prepare us for other arenas...where we all are players and where our choices have more significance than any World Series or Super Bowl. Join Dr. Bill Thierfelder in an exploration of sport-and of life-as you have never considered them before. Let this world-class athlete, mentor and coach teach you what he has taught so many others, from college students to superstars: How to give your very best when the clock is ticking...everything is on the line...and you have Less Than a Minute to Go.
Since 1 January 2004, inpatient treatment services in German hospitals have been reimbursed using a prospective payment method based on diagnosis-related groups (DRGs) rather than daily rates. The ...aim of the payment system reform was to decrease the length of inpatient stays and reduce overall healthcare expenditure, the latter of which had increased markedly during previous decades.
The primary objective of our study was to analyse and describe the health-economic consequences of implementing a DRG-based system of prospective payment in Germany.
A systematic search of the literature was performed on MEDLINE. Inclusion criteria were a focus on health economic variables from the German perspective and a publication date after 1 January 2004. The search was supplemented by a manual review of references, as well as internet-based hand search. The main health-economic conclusions were subsequently extracted from all of the included studies.
A total of 19 quantitative and qualitative studies were included. There were substantial differences between them in terms of medical focus and hospital characteristics. The most common health-economic variables analysed were revenue generated by patient treatment, and length of inpatient stay. As expected, both variables showed a decreasing trend following the introduction of DRGs. The included studies also investigated the development of case numbers, the proportion of outpatient services provided, the number of diagnoses per case, and the homogeneity of case groups. For these variables, the studies showed a wide range of results.
Similar to the experience with DRGs in many other countries, the introduction of DRGs in Germany has led to a reduction in the length of inpatient stay and a decrease in hospital revenues. The effects on other health-economic parameters are inconsistent. Additional studies in this area are needed.
Information shortage is a fundamental constraint in catchment hydrology that severely affects the possibilities for secure inference of the generic hydrologic landscape, as well as for secure ...validation of physically deduced distributed models. The introduction of databases with high enough spatiotemporal resolution to properly reflect generic hydrological catchment characteristics may therefore be considered as an inferential breakthrough. The work presented here is part of a project where observations from such an Australian catchment (the Tarrawarra) are utilised to estimate the discrepancy for individual soil moisture monitoring sites in reflecting generic catchment characteristics. With low enough discrepancy, observation sites may be considered as catchment characteristic soil moisture monitoring (CASMM) sites, thus capturing unbiased catchment characteristics and being well suited to represent the catchment in a monitoring effort. In this particular study, covariance structures in the temporal domain are inferred in order to enable subsequent enquiries regarding CASMM discrepancies. This is accomplished with ARMAX filters applied to the conditional auto- and cross-covariance structures that connect observations of soil moisture to the temporal variation of meteorology. The results suggest that weekly observations of Tarrawarra soil moisture are quite consistent realisations of first order auto-regressive processes, which means that the present state of soil moisture is generally acquired through the past week. With auto-correlative effects filtered out, cross-correlative meteorological effects on Tarrawarra soil moisture are identified and generally represented by the present week's accumulation of rainfall, the present week's accumulation of global radiation, and the previous week's maximum wind speed. After successive filtering of conditional cross-correlative effects, residual time-series observations may be considered as temporally independent, and therefore are well suited for subsequent inferences regarding covariance structures in the spatial domain. Since the exclusion of auto-correlative effects is necessary for unambiguous model interpretation, the estimated cross-correlative parameters should reflect the true nature of underlying physical processes.
Injuries of the ligaments and tendons of the ankle and foot are among the most common musculoskeletal injuries. A correct and precise description of the pathology and possible accompanying injuries ...is essential for treatment planning by trauma and orthopedic surgeons. While X‑ray is used to exclude fractures, ultrasound is a very useful tool to assess the ligaments and tendons. For the radiologist, magnetic resonance imaging (MRI) is invaluable regarding the correct assessment of (partial) ruptures, as well as for evaluating accompanying injuries. The aim of the present overview is to provide the most relevant facts for radiologists regarding injuries of ligaments and tendons of the ankle and foot. A description of expected MRI findings and possible pitfalls are presented. For each ligament complex or tendon, we review the anatomy, followed by relevant facts on biomechanics and typical findings in case of injury. The lateral and medial ligament complex, syndesmosis, spring ligament complex, and the Lisfranc ligament are shown in detail. The Achilles tendon and the peroneal tendons are also discussed.
Advocates of the use of genetic engineering techniques in agriculture contend that this new biotechnology promises increased productivity, better use of natural resources and more nutritious foods. ...Opponents are concerned about potentially adverse implications for the environment and food safety. In response to consumer reactions against genetically modified (GM) foods, in some countries crop production is being segregated into GM and non-GM varieties. This analysis finds that world markets for maize and soybeans adjust well to these changes and also that developing countries will divert their trade patterns in response to preference changes in important trading partner countries.
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