Browsing by Subject "Retrospective Studies"
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Item Open Access A comprehensive methodology for determining the most informative mammographic features(2013) Wu, Y.; Alagoz O.; Ayvaci, M.U.S.; Munoz Del Rio, A.; Vanness, D.J.; Woods, R.; Burnside, E.S.This study aims to determine the most informative mammographic features for breast cancer diagnosis using mutual information (MI) analysis. Our Health Insurance Portability and Accountability Act-approved database consists of 44,397 consecutive structured mammography reports for 20,375 patients collected from 2005 to 2008. The reports include demographic risk factors (age, family and personal history of breast cancer, and use of hormone therapy) and mammographic features from the Breast Imaging Reporting and Data System lexicon. We calculated MI using Shannon's entropy measure for each feature with respect to the outcome (benign/malignant using a cancer registry match as reference standard). In order to evaluate the validity of the MI rankings of features, we trained and tested naïve Bayes classifiers on the feature with tenfold cross-validation, and measured the predictive ability using area under the ROC curve (AUC). We used a bootstrapping approach to assess the distributional properties of our estimates, and the DeLong method to compare AUC. Based on MI, we found that mass margins and mass shape were the most informative features for breast cancer diagnosis. Calcification morphology, mass density, and calcification distribution provided predictive information for distinguishing benign and malignant breast findings. Breast composition, associated findings, and special cases provided little information in this task. We also found that the rankings of mammographic features with MI and AUC were generally consistent. MI analysis provides a framework to determine the value of different mammographic features in the pursuit of optimal (i.e., accurate and efficient) breast cancer diagnosis. © 2013 Society for Imaging Informatics in Medicine.Item Open Access Early outcomes after transoral CO2 laser resection of laryngeal and hypopharyngeal squamous cell carcinoma: One centre's experience(Cambridge University Press, 2010) Leong, S. C.; Kathan, C.; Mortimore, S.Objectives: To review early oncological outcomes following transoral CO2 laser resection of laryngeal and hypopharyngeal squamous cell carcinoma. Design: Retrospective review of hospital electronic database. Setting: Large district general hospital in England, UK.Main outcome measures: Patients' three-year disease-specific survival and disease-free survival were evaluated, including post-operative complications, voice quality and swallowing status. Results: Seventy-seven patients (16 women and 61 men) were identified. Transoral laser excision of squamous cell carcinoma of the larynx was undergone by 65 patients, and the same procedure in the hypopharynx by 12. Patients with laryngeal cancer had statistically better disease-specific survival than those with hypopharyngeal cancer (p=0.021), although the cumulative disease-free survival probability was 0.71 for both larynx and hypopharynx groups. Patients who underwent laryngectomy following failed laser treatment or as a salvage procedure had poorer outcomes.Conclusions: The overall results of this study were comparable with those of other, larger studies. At three-year follow up, cumulative disease-specific survival probabilities were 0.92 and 0.71 for laryngeal and hypopharyngeal squamous cell carcinoma, respectively. Copyright © JLO (1984) Limited 2009.Item Open Access High-resolution magic anglespinning ¹H nuclear magnetic resonance spectroscopy metabolomics of hyperfunctioning parathyroid glands(Mosby, Inc., 2016) Battini, S.; Imperiale, A.; Taïeb, D.; Elbayed, K.; Cicek, A. E.; Sebag, F.; Brunaud, L.; Namer, Izzie-JacquesBackground Primary hyperparathyroidism (PHPT) may be related to a single gland disease or multiglandular disease, which requires specific treatments. At present, an operation is the only curative treatment for PHPT. Currently, there are no biomarkers available to identify these 2 entities (single vs. multiple gland disease). The aims of the present study were to compare (1) the tissue metabolomics profiles between PHPT and renal hyperparathyroidism (secondary and tertiary) and (2) single gland disease with multiglandular disease in PHPT using metabolomics analysis. Methods The method used was 1H high-resolution magic angle spinning nuclear magnetic resonance spectroscopy. Forty-three samples from 32 patients suffering from hyperparathyroidism were included in this study. Results Significant differences in the metabolomics profile were assessed according to PHPT and renal hyperparathyroidism. A bicomponent orthogonal partial least square-discriminant analysis showed a clear distinction between PHPT and renal hyperparathyroidism (R2Y = 0.85, Q2 = 0.63). Interestingly, the model also distinguished single gland disease from multiglandular disease (R2Y = 0.96, Q2 = 0.55). A network analysis was also performed using the Algorithm to Determine Expected Metabolite Level Alterations Using Mutual Information (ADEMA). Single gland disease was accurately predicted by ADEMA and was associated with higher levels of phosphorylcholine, choline, glycerophosphocholine, fumarate, succinate, lactate, glucose, glutamine, and ascorbate compared with multiglandular disease. Conclusion This study shows for the first time that 1H high-resolution magic angle spinning nuclear magnetic resonance spectroscopy is a reliable and fast technique to distinguish single gland disease from multiglandular disease in patients with PHPT. The potential use of this method as an intraoperative tool requires specific further studies.Item Open Access Ischemic stroke phenotype in patients with nonsustained atrial fibrillation(Lippincott Williams and Wilkins, 2015) Arsava, E. M.; Bas, D. F.; Atalar, Ergin; Has, A. C.; Oguz, K. K.; Topcuoglu, M. A.Background and Purpose: The widespread use of ambulatory cardiac monitoring has not only increased the detection of high-risk arrhythmias like persistent and paroxysmal atrial fibrillation (AF), but also made it possible to identify other aberrations such as short-lasting (<30 seconds) irregular runs of supraventricular tachycardia. Ischemic stroke phenotype might be helpful in understanding whether these nonsustained episodes play a similar role in stroke pathophysiology like their persistent and paroxysmal counterparts. Methods: In a consecutive series of patients with ischemic stroke, we retrospectively determined clinical and imaging features associated with nonsustained AF (n=126), defined as <30-second-lasting supraventricular tachyarrhythmias with irregular RR interval on 24-hour Holter monitoring, and compared them to patients with persistent/paroxysmal AF (n=239) and no AF (n=246). Results: Patients with persistent/paroxysmal AF significantly differed from patients with nonsustained AF by a higher prevalence of female sex (odds ratio [95% confidence interval], 1.8 [1.1-2.9]), coronary artery disease (1.9 [1.1-3.0]), and embolic imaging features (2.7 [1.1-6.5]), and lower frequency of smoking (0.4 [0.2-0.8]) and hyperlipidemia (0.5 [0.3-0.8]). In contrast, patients with no AF were younger (0.5 [0.4-0.6] per decade) and more likely to be male (1.7 [1.0-2.8]) in comparison with nonsustained AF population. The prevalence of nonsustained AF was similar among cryptogenic and noncryptogenic stroke patients (32% versus 29%). Voxel-wise comparison of lesion probability maps revealed no significant difference between cryptogenic stroke patients with and without nonsustained AF. Conclusions: Clinical features of patients with nonsustained AF exhibited an intermediary phenotype in between patients with persistent/paroxysmal AF and no AF. Furthermore, imaging features did not entirely resemble patterns observed in patients with longer durations of AF.Item Open Access Malignant-lesion segmentation using 4D co-occurrence texture analysis applied to dynamic contrast-enhanced magnetic resonance breast image data(2007) Woods, B.J.; Clymer, B.D.; Kurc, T.; Heverhagen J.T.; Stevens, R.; Orsdemir, A.; Bulan O.; Knopp, M.V.Purpose: To investigate the use of four-dimensional (4D) co-occurrence-based texture analysis to distinguish between nonmalignant and malignant tissues in dynamic contrast-enhanced (DCE) MR images. Materials and Methods: 4D texture analysis was performedon DCE-MRI data sets of breast lesions. A model-free neural network-based classification system assigned each voxel a "nonmalignant" or "malignant" label based on the textural features. The classification results were compared via receiver operating characteristic (ROC) curve analysis with the manual lesion segmentation produced by two radiologists (observers 1 and 2). Results: The mean sensitivity and specificity of the classifier agreed with the mean observer 2 performance when compared with segmentations by observer 1 for a 95% confidence interval, using a two-sided t-test with α = 0.05. The results show that an area under the ROC curve (Az) of 0.99948, 0.99867, and 0.99957 can be achieved by comparing the classifier vs. observer 1, classifier vs. union of both observers, and classifier vs. intersection of both observers, respectively. Conclusion: This study shows that a neural network classifier based on 4D texture analysis inputs can achieve a performance comparable to that achieved by human observers, and that further research in this area is warranted. © 2007 Wiley-Liss, Inc.