bluuebunny/crossref_metadata_2025_split huggingface dataset:
Quality of Heart Failure Management: A Comparison of Care Between a Comprehensive Heart Failure Program and a General Cardiology Practice
Authors: Asghar Hannah , Rahko Peter S. 
Published: December 2009

This study evaluates adherence to guidelines by heart failure clinicians (HFCs) vs general cardiologists (GCs) for use of implantable cardioverter‐defibrillators (ICDs), biventricular pacing devices (cardiac resynchronization therapy; CRT), and use of medications for heart failure (HF). The authors reviewed 563 patients with HF and an ejection fraction ≤35% for adherence to the 2005 American College of Cardiology/American Heart Association HF guidelines for the use of ICDs, CRT, and medications. There were 324 HFC and 239 GC patients. CRT guidelines were appropriately followed in 86% of HFC and 81% of GC patients ( P=NS). For primary arrhythmia prevention, an ICD was implanted in 107 (42%) HFC and 50 (25%) GC patients ( P<.004). Guidelines were appropriately followed in 77% of HFC and 74% of GC patients ( P=NS). For medications, dose intensity of diuretics, β‐blockers, and angiotensin‐converting enzyme inhibitors was significantly greater in HFC than GC patients. Guideline‐recommended β‐blockers were more frequently utilized by HFCs (97%) than GCs (82%). In conclusion, HFCs and GCs appropriately follow guidelines in the majority of cases, but HFCs use appropriate medications at higher dose intensity.Congest Heart Fail. 2010;16:65–70. © 2009 Wiley Periodicals, Inc.
The quest for Y‐chromosomal markers – methodological strategies for mammalian non‐model organisms
Authors: GREMINGER MAJA P. , KRÜTZEN MICHAEL , SCHELLING CLAUDE , PIENKOWSKA–SCHELLING ALDONA , WANDELER PETER 
Published: December 2009

AbstractTracing maternal and paternal lineages independently to explore breeding systems and dispersal strategies in natural populations has been high on the wish‐list of evolutionary biologists. As males are the heterogametic sex in mammals, such sex‐specific patterns can be indirectly observed when Y chromosome polymorphism is combined with mitochondrial sequence information. Over the past decade, Y‐chromosomal markers applied to human populations have revealed remarkable differences in the demographic history and behaviour between the sexes. However, with a few exceptions, genetic data tracing the paternal line are lacking in most other mammalian species. This deficit can be attributed to the difficulty of developing Y‐specific genetic markers in non‐model organisms and the general low levels of polymorphisms observed on the Y chromosome. Here, we present an overview of the currently employed strategies for developing paternal markers in mammals. Moreover, we review the practical feasibility and requirements of various methodological strategies and highlight their future prospects when combined with new molecular techniques such as next generation sequencing.
Minimally invasive straight laparoscopic total proctocolectomy for ulcerative colitis
Authors: Ozawa H. , Kokuba Y. , Nakamura T. , Naito M. , Sato T. , Hatate K. , Onozato W. , Miura H. , Tsutsui A. , Ikeda A. , Ihara A. , Watanabe M. 
Published: December 2009

AbstractIntroduction: We have performed straight laparoscopic total proctocolectomy for ulcerative colitis, in which all procedures, including transection of the rectum and anastomosis, were performed in the abdominal cavity. The primary objective of this study was to evaluate whether straight laparoscopic total proctocolectomy is technically feasible and safe.Methods: A retrospective database identified 22 consecutive patients who underwent straight laparoscopic total proctocolectomy for ulcerative colitis between March 1998 and September 2007. Patients were excluded if they required emergency surgery. First, to create a stoma site, a mini‐laparotomy to insert a 15 mm trocar was performed. Seven other trocars, 5 mm in diameter, were then inserted. Mobilization and dissection of the colorectum and anastmosis were performed completely intracorporeally under laparoscopic guidance. Anastomosis of an ileal J‐pouch to the anal canal was performed using the double‐stapling technique.Results: Nineteen patients were underwent ileal pouch anal canal anastomosis; two underwent ileorectal anastomosis; and one underwent abdominoperineal resection. The median operation time was 355 min (range 255–605); the median blood loss was 50 g (range 0–800); and the median postoperative hospital stay was 24.5 d. Postoperative complications occurred in eight patients, including three (13.6%) with bowel obstruction, two (9.1%) with portal vein thrombosis, one (4.5%) with anastomotic leakage, and one (4.5%) with postoperative hemorrhage. The morbidity rate was 36.4%. There were no intraoperative complications or conversions to conventional surgery.Conclusion: In the context of this study, we have shown that straight laparoscopic total proctocolectomy is technically feasible and safe in patients with ulcerative colitis.
Laparoscopic sphincter‐preserving surgery for low rectal tumor using prolapsing technique
Authors: Zheng M.H. , Ma J.J. , Zhang T. , Zhu Q.L. , Lu A.G. , Zong Y.P. , Wang M.L. , Li J.W. , Hu W.G. , Mao Z.H. , Dong F. , Zang L. 
Published: December 2009

AbstractIntroduction: With this study, we aimed to assess the feasibility and outcome of laparoscopy‐assisted low anterior resection with a prolapsing technique for low rectal tumors.Materials and Methods: We studied surgical techniques, recovery status, complications, oncological clearance and the results of short‐term follow‐up in 15 patients who had received laparoscopy‐assisted low anterior resection with a prolapsing technique for low rectal tumors between October 2005 and January 2008.Results: None of the cases was converted to open surgery. The mean operation time was 185  min (150–232 min), and the mean blood loss was 75 ml (25–105 ml). The mean time for passage of flatus, duration of urinary drainage, and postoperative hospital stay were 3 d (1–4 d), 6 d (5–10 d) and 11 d (7–20 d), respectively. The total amount of lymph nodes harvested was 15 (9–21), and the mean distal margin from the tumor was 2.5 cm (1.0–3.9 cm). No major complications were observed. The mean follow‐up time was 13 months (4–27 months). Neither local recurrence nor metastasis was observed. Acceptable anal function results were obtained in most patients.Discussion: Laparoscopy‐assisted low anterior resection with a prolapsing technique can be successfully performed.
Improved MAGIC gel for higher sensitivity and elemental tissue equivalent 3D dosimetry
Authors: Zhu Xuping , Reese Timothy G. , Crowley Elizabeth M. , El Fakhri Georges 
Published: December 2009

PurposePolymer‐based gel dosimeter (MAGIC type) is a preferable phantom material for PET range verification of proton beam therapy. However, improvement in elemental tissue equivalency (specifically O/C ratio) is very desirable to ensure realistic time‐activity measurements.MethodsGlucose and urea was added to the original MAGIC formulation to adjust the O/C ratio. The dose responses of the new formulations were tested with MRI transverse relaxation rate (R2) measurements.ResultsThe new ingredients improved not only the elemental composition but also the sensitivity of the MAGIC gel. The O/C ratios of our new gels agree with that of soft tissue within 1%. The slopes of dose response curves were 1.6–2.7 times larger with glucose. The melting point also increased by . Further addition of urea resulted in a similar slope but with an increased intercept and a decreased melting point.ConclusionsOur improved MAGIC gel formulations have higher sensitivity and better elemental tissue equivalency for 3D dosimetry applications involving nuclear reactions.
Evaluation of the interplay effect when using RapidArc to treat targets moving in the craniocaudal or right‐left direction
Authors: Court Laurence , Wagar Matthew , Berbeco Ross , Reisner Adam , Winey Brian , Schofield Debbie , Ionascu Dan , Allen Aaron M. , Popple Richard , Lingos Tania 
Published: December 2009

PurposeWe have investigated the dosimetric errors caused by the interplay between the motions of the LINAC and the tumor during the delivery of a volume modulated arc therapy treatment. This includes the development of an IMRT QA technique, applied here to evaluate RapidArc plans of varying complexity.MethodsAn IMRT QA technique was developed, which involves taking a movie of the delivered dose (0.2 s frames) using a 2D ion chamber array. Each frame of the movie is then moved according to a respiratory trace and the cumulative dose calculated. The advantage of this approach is that the impact of turning the beam on at different points in the respiratory trace, and of different types of motion, can be evaluated using data from a single irradiation. We evaluated this technique by comparing with the results when we actually moved the phantom during irradiation. RapidArc plans were created to treat a 62 cc spherical tumor in a lung phantom (16 plans) and a 454 cc irregular tumor in an actual patient (five plans). The complexity of each field was controlled by adjusting the MU (312–966 MU). Each plan was delivered to a phantom, and a movie of the delivered dose taken using a 2D ion chamber array. Patient motion was modeled by shifting each dose frame according to a respiratory trace, starting the motion at different phases. The expected dose distribution was calculated by blurring the static dose distribution with the target motion. The dose error due to the interplay effect was then calculated by comparing the delivered dose with the expected dose distribution. Peak‐to‐peak motion of 0.5, 1.0, and 2.0 cm in the craniocaudal and right‐left directions, with target periods of 3 and 5 s, were evaluated for each plan (252 different target motion/plan combinations).ResultsThe daily dose error due to the interplay effect was less than 10% for 98.4% of all pixels in the target for all plans investigated. The percentage of pixels for which the daily dose error could be larger than 5% increased with increasing plan complexity (field MU), but was less than 15% for all plans if the motion was 1 cm or less. For 2 cm motion, the dose error could be larger than 5% for 40% of pixels, but was less than 5% for more than 80% of pixels for , and was less than 10% for 99% of all pixels. The interplay effect was smaller for 3 s periods than for 5 s periods.ConclusionsThe interplay between the motions of the LINAC and the target can result in an error in the delivered dose. This effect increases with plan complexity, and with target magnitude and period. It may average out after many fractions.
CT colonography: Advanced computer‐aided detection scheme utilizing MTANNs for detection of “missed” polyps in a multicenter clinical trial
Authors: Suzuki Kenji , Rockey Don C. , Dachman Abraham H. 
Published: December 2009

PurposeThe purpose of this study was to develop an advanced computer‐aided detection (CAD) scheme utilizing massive‐training artificial neural networks (MTANNs) to allow detection of “difficult” polyps in CT colonography (CTC) and to evaluate its performance on false‐negative (FN) CTC cases that radiologists “missed” in a multicenter clinical trial.MethodsThe authors developed an advanced CAD scheme consisting of an initial polyp‐detection scheme for identification of polyp candidates and a mixture of expert MTANNs for substantial reduction in false positives (FPs) while maintaining sensitivity. The initial polyp‐detection scheme consisted of (1) colon segmentation based on anatomy‐based extraction and colon‐based analysis and (2) detection of polyp candidates based on a morphologic analysis on the segmented colon. The mixture of expert MTANNs consisted of (1) supervised enhancement of polyps and suppression of various types of nonpolyps, (2) a scoring scheme for converting output voxels into a score for each polyp candidate, and (3) combining scores from multiple MTANNs by the use of a mixing artificial neural network. For testing the advanced CAD scheme, they created a database containing 24 FN cases with 23 polyps (range of ; average of ) and a mass , which were “missed” by radiologists in CTC in the original trial in which 15 institutions participated.ResultsThe initial polyp‐detection scheme detected 63% of the missed polyps with 21.0 FPs per patient. The MTANNs removed 76% of the FPs with loss of one true positive; thus, the performance of the advanced CAD scheme was improved to a sensitivity of 58% with 8.6 FPs per patient, whereas a conventional CAD scheme yielded a sensitivity of 25% at the same FP rate (the difference was statistically significant).ConclusionsWith the advanced MTANN CAD scheme, 58% of the polyps missed by radiologists in the original trial were detected and with a reasonable number of FPs. The results suggest that the use of an advanced MTANN CAD scheme may potentially enhance the detection of “difficult” polyps.
Automatic selection of tube potential for radiation dose reduction in CT: A general strategy
Authors: Yu Lifeng , Li Hua , Fletcher Joel G. , McCollough Cynthia H. 
Published: December 2009

PurposeTo optimize radiation dose efficiency in CT while maintaining image quality, it is important to select the optimal tube potential. The selection of optimal tube potential, however, is highly dependent on patient size and diagnostic task. The purpose of this work was to develop a general strategy that allows for automatic tube potential selection for each individual patient and each diagnostic task.MethodsThe authors propose a general strategy that allows automatic adaptation of the tube potential as a function of patient size and diagnostic task, using a novel index of image quality, “iodine contrast to noise ratio with a noise constraint (iCNR_NC),” to characterize the different image quality requirements by various clinical applications. The relative dose factor (RDF) at each tube potential to achieve a target image quality was then determined as a function of patient size and the noise constraint parameter. A workflow was developed to automatically identify the optimal tube potential that is both dose efficient and practically feasible, incorporating patient size and diagnostic task. An experimental study using a series of semianthropomorphic thoracic phantoms was used to demonstrate how the proposed general strategy can be implemented and how the radiation dose reduction achievable by the tube potential selection depends on phantom sizes and noise constraint parameters.ResultsThe proposed strategy provides a flexible and quantitative way to select the optimal tube potential based on the patient size and diagnostic task. The noise constraint parameter can be adapted for different clinical applications. For example, for noncontrast routine exams; for contrast‐enhanced routine exams; and for CT angiography. For the five thoracic phantoms in the experiment, when , the optimal tube potentials were 80, 100, 100, 120, 120, respectively. The corresponding RDFs (relative to 120 kV) were 78.0%, 90.9%, 95.2%, 100%, and 100%. When , the optimal tube potentials were 80, 80, 80, 100, 100, respectively, with corresponding RDFs of 34.7%, 44.7%, 54.7%, 60.8%, and 89.5%.ConclusionsA general strategy to automatically select the most dose efficient tube potential for CT exams was developed that takes into account patient size and diagnostic task. Dependent on the patient size and the selection of noise constraint parameter for different diagnostic tasks, the dose reduction at each tube potential, quantified explicitly with the RDF, varies significantly.
Calibration of a novel four‐dimensional diode array
Authors: Yan Guanghua , Lu Bo , Kozelka Jakub , Liu Chihray , Li Jonathan G. 
Published: December 2009

PurposeThe aim of this work is to develop effective calibration methods for a novel four‐dimensional (4D) diode array for pretreatment verification of intensity‐modulated radiation therapy (IMRT) and rotational therapy.MethodsA novel 4D diode array (ArcCHECK, Sun Nuclear, Melbourne, FL) was developed to meet the needs of appropriate and efficient quality assurance for IMRT and especially rotational radiotherapy. The diode array presents a consistent detector image in beam's eye view at arbitrary gantry angles due to isotropic arrangement of diodes in a three‐dimensional (3D) cylindrical phantom. The simultaneous update of all diodes on the detector array (fourth dimension) makes it capable of time‐resolved beam delivery analysis with any rotational delivery techniques. The calibration procedure consisted of delivering and measuring a series of calibration beams with 5.8° angular spacing surrounding the cylindrical diode array. Correction factors for diode intrinsic sensitivity and directional response dependence were derived from these measurements. A real‐time algorithm to derive gantry angles based on the detector signal was developed to interpolate and apply the corresponding angular correction factors.ResultsThe calibration was validated with ion chamber scanned beam profiles in a 3D water tank. Excellent agreement was observed between diode array measurement and treatment planning system calculation. The accuracy of the gantry angle derivation algorithm was within 1° which caused a less than 0.2% dosimetric uncertainty.ConclusionsWith the proposed calibration method and the automatic gantry angle derivation algorithm, the 4D diode array achieved isotropic detector response and is suitable for both IMRT and rotational therapy pretreatment verification.
Exploring nonlinear feature space dimension reduction and data representation in breast CADx with Laplacian eigenmaps and ‐SNE
Authors: Jamieson Andrew R. , Giger Maryellen L. , Drukker Karen , Li Hui , Yuan Yading , Bhooshan Neha 
Published: December 2009

PurposeIn this preliminary study, recently developed unsupervised nonlinear dimension reduction (DR) and data representation techniques were applied to computer‐extracted breast lesion feature spaces across three separate imaging modalities: Ultrasound (U.S.) with 1126 cases, dynamic contrast enhanced magnetic resonance imaging with 356 cases, and full‐field digital mammography with 245 cases. Two methods for nonlinear DR were explored: Laplacian eigenmaps [M. Belkin and P. Niyogi, “Laplacian eigenmaps for dimensionality reduction and data representation,” Neural Comput. 15, 1373–1396 (2003)] and ‐distributed stochastic neighbor embedding (‐SNE) [L. van der Maaten and G. Hinton, “Visualizing data using t‐SNE,” J. Mach. Learn. Res. 9, 2579–2605 (2008)].MethodsThese methods attempt to map originally high dimensional feature spaces to more human interpretable lower dimensional spaces while preserving both local and global information. The properties of these methods as applied to breast computer‐aided diagnosis (CADx) were evaluated in the context of malignancy classification performance as well as in the visual inspection of the sparseness within the two‐dimensional and three‐dimensional mappings. Classification performance was estimated by using the reduced dimension mapped feature output as input into both linear and nonlinear classifiers: Markov chain Monte Carlo based Bayesian artificial neural network (MCMC‐BANN) and linear discriminant analysis. The new techniques were compared to previously developed breast CADx methodologies, including automatic relevance determination and linear stepwise (LSW) feature selection, as well as a linear DR method based on principal component analysis. Using ROC analysis and validation, 95% empirical confidence intervals were computed for the each classifier's AUC performance.ResultsIn the large U.S. data set, sample high performance results include, with 95% empirical bootstrap interval [0.787;0.895] for 13 ARD selected features and with interval [0.817;0.906] for four LSW selected features compared to 4D t‐SNE mapping (from the original 81D feature space) giving with interval [0.847;0.919], all using the MCMC‐BANN.ConclusionsPreliminary results appear to indicate capability for the new methods to match or exceed classification performance of current advanced breast lesion CADx algorithms. While not appropriate as a complete replacement of feature selection in CADx problems, DR techniques offer a complementary approach, which can aid elucidation of additional properties associated with the data. Specifically, the new techniques were shown to possess the added benefit of delivering sparse lower dimensional representations for visual interpretation, revealing intricate data structure of the feature space.
Dose perturbations by two carbon fiber treatment couches and the ability of a commercial treatment planning system to predict these effects
Authors: Gerig L. H. , Niedbala M. , Nyiri B. J. 
Published: December 2009

PurposeTo measure the effect of the treatment couch on dose distributions and to investigate the ability of a modern planning system to accurately model these effects.MethodsThis work measured the dose perturbation at depth and in the dose buildup region when one of two treatment couches, CIVCO (formerly MED‐TEC) or Medical Intelligence, was placed between a photon beam source (6, 10, and 18 MV) and the phantom. Beam attenuation was measured in the center of a cylindrical acrylic phantom with a Farmer type ion chamber at multiple gantry angles. Dose buildup was measured in Solid Water with plane parallel ion chambers (NACP‐02 and PTW Markus) with the beam normal to both the phantom and couch surfaces. The effective point of measurement method as described [M. R. McEwen et al. “The effective point of measurement of ionization chambers and the build‐up anomaly in MV x‐ray beams,” Med. Phys. 35(3), 950–958 (2008)] was employed to calculate dose in the buildup region. Both experiments were modeled in XiO. Images of the treatment couches were merged with images of the phantoms such that they were included as part of the “patient” image. Dose distributions calculated with superposition and fast superposition algorithms were compared to measurement.ResultsThe two treatment couches have different radiological signatures and dissimilar water equivalent thicknesses (4.2 vs 6.3 mm.) Maximum attenuation was 7%. Both couches caused significant loss of skin sparing, the worst case showing an increase in surface dose from 17% (no couch) to 88% (with couch). The TPS accurately predicted the surface dose (±3%) and the attenuation at depth when the phantom was in contact with the couch. For the open beam the TPS was less successful in the buildup region.ConclusionsThe treatment couch is not radio‐transparent. Its presence between the patient and beam source significantly alters dose in the patient. For the most part, a modern treatment planning system can adequately predict the altered dose distribution.