Signaling local non-credibility in an automatic segmentation pipeline

The advancing technology for automatic segmentation of medical images should be accompanied by techniques to inform the user of the local credibility of results. To the extent that this technology produces clinically acceptable segmentations for a significant fraction of cases, there is a risk that the clinician will assume every result is acceptable. In the less frequent case where segmentation fails, we are concerned that unless the user is alerted by the computer, she would still put the result to clinical use. By alerting the user to the location of a likely segmentation failure, we allow her to apply limited validation and editing resources where they are most needed. We propose an automated method to signal suspected non-credible regions of the segmentation, triggered by statistical outliers of the local image match function. We apply this test to m-rep segmentations of the bladder and prostate in CT images using a local image match computed by PCA on regional intensity quantile functions. We validate these results by correlating the non-credible regions with regions that have surface distance greater than 5.5mm to a reference segmentation for the bladder. A 6mm surface distance was used to validate the prostate results. Varying the outlier threshold level produced a receiver operating characteristic with area under the curve of 0.89 for the bladder and 0.92 for the prostate. Based on this preliminary result, our method has been able to predict local segmentation failures and shows potential for validation in an automatic segmentation pipeline

Comparison of Image Registration Based Measures of Regional Lung Ventilation from Dynamic Spiral CT with Xe-CT

Purpose: Regional lung volume change as a function of lung inflation serves as an index of parenchymal and airway status as well as an index of regional ventilation and can be used to detect pathologic changes over time. In this article, we propose a new regional measure of lung mechanics --- the specific air volume change by corrected Jacobian. Methods: 4DCT and Xe-CT data sets from four adult sheep are used in this study. Nonlinear, 3D image registration is applied to register an image acquired near end inspiration to an image acquired near end expiration. Approximately 200 annotated anatomical points are used as landmarks to evaluate registration accuracy. Three different registration-based measures of regional lung mechanics are derived and compared: the specific air volume change calculated from the Jacobian (SAJ); the specific air volume change calculated by the corrected Jacobian (SACJ); and the specific air volume change by intensity change (SAI). Results: After registration, the mean registration error is on the order of 1 mm. For cubical ROIs in cubes with size 20 mm $\times$ 20 mm $\times$ 20 mm, the SAJ and SACJ measures show significantly higher correlation (linear regression, average $r^2=0.75$ and $r^2=0.82$) with the Xe-CT based measure of specific ventilation (sV) than the SAI measure. For ROIs in slabs along the ventral-dorsal vertical direction with size of 150 mm $\times$ 8 mm $\times$ 40 mm, the SAJ, SACJ, and SAI all show high correlation (linear regression, average $r^2=0.88$, $r^2=0.92$ and $r^2=0.87$) with the Xe-CT based sV without significant differences when comparing between the three methods. Conclusion: Given a deformation field by an image registration algorithm, significant differences between the SAJ, SACJ, and SAI measures were found at a regional level compared to the Xe-CT sV in four sheep that were studied

Hybrid Committee Classifier for a Computerized Colonic Polyp Detection System

We present a hybrid committee classifier for computer-aided detection (CAD) of colonic polyps in CT colonography (CTC). The classifier involved an ensemble of support vector machines (SVM) and neural networks (NN) for classification, a progressive search algorithm for selecting a set of features used by the SVMs and a floating search algorithm for selecting features used by the NNs. A total of 102 quantitative features were calculated for each polyp candidate found by a prototype CAD system. 3 features were selected for each of 7 SVM classifiers which were then combined to form a committee of SVMs classifier. Similarly, features (numbers varied from 10-20) were selected for 11 NN classifiers which were again combined to form a NN committee classifier. Finally, a hybrid committee classifier was defined by combining the outputs of both the SVM and NN committees. The method was tested on CTC scans (supine and prone views) of 29 patients, in terms of the partial area under a free response receiving operation characteristic (FROC) curve (AUC). Our results showed that the hybrid committee classifier performed the best for the prone scans and was comparable to other classifiers for the supine scans

Automated Quantitative Analysis of a Mouse Model of Chronic Pulmonary Inflammation using Micro X-ray Computed Tomography

Micro-CT has emerged as an excellent tool for in-vivo imaging of the lungs of small laboratory animals. Several studies have shown that it can be used to assess the evolution of pulmonary lung diseases in longitudinal studies. However, most of them rely on non-automatic tools for image analysis, or are merely qualitative. In this article, we present a longitudinal, quantitative study of a mouse model of silica-induced pulmonary inflammation. To automatically assess disease progression, we have devised and validated a lung segmentation method that combines threshold-based segmentation, atlas-based segmentation and level sets. Our volume measurements, based on the automatic segmentations, point at a compensation mechanism which leads to an increase of the healthy lung volume in response to the loss of functional tissue caused by inflammation

Effect of Segmental Bronchoalveolar Lavage on Quantitative Computed Tomography of the Lung

Rationale and Objectives: With employment of both multidetector computed tomography (MDCT) and endobronchial procedures in multicenter studies, effects of timing of endobronchial procedures on quantitative imaging (Q-MDCT) metrics is a question of increasing importance.Materials and Methods: Six subjects were studied via MDCT at baseline, immediately following and at 4 hours and 24 hours post-bronchoalveolar lavage (SAL) (right middle lobe and lingula). Through quantitative image analysis, non-air, or "tissue" volume (TV) in each lung and lobe was recorded. Change in TV from baseline was used to infer retention and redistribution of lavage fluid.Results: Bronchoscopist reported unrecovered BAL volume correlated well with Q-MDCT for whole lung measures, but less well with individual lobes indicating redistribution. TV in all lobes except the right lower lobe differed significantly (P &lt;.05) from baseline immediately post lavage. At 24 hours, all lobes except the left lower lobe (small 1% mean difference at 24 hours) returned to baseline.Conclusions: These findings suggest fluid movement affecting Q-MDCT metrics between lobes and between lungs before eventual resolution, and preclude protocols involving the lavage of one lung and imaging of the other to avoid interactions. We demonstrate that Q-MDCT is sensitive to lavage fluid retention and redistribution, and endobronchial procedures should not precede Q-MDCT imaging by less than 24 hours.</p

Perspectives from deductible plan enrollees: plan knowledge and anticipated care-seeking changes

<p>Abstract</p> <p>Background</p> <p>Consumer directed health care proposes that patients will engage as informed consumers of health care services by sharing in more of their medical costs, often through deductibles. We examined knowledge of deductible plan details among new enrollees, as well as anticipated care-seeking changes in response to the deductible.</p> <p>Methods</p> <p>In a large integrated delivery system with a range of deductible-based health plans which varied in services included or exempted from deductible, we conducted a mixed-method, cross-sectional telephone interview study.</p> <p>Results</p> <p>Among 458 adults newly enrolled in a deductible plan (71% response rate), 51% knew they had a deductible, 26% knew the deductible amount, and 6% knew which medical services were included or exempted from their deductible. After adjusting for respondent characteristics, those with more deductible-applicable services and those with lower self-reported health status were significantly more likely to know they had a deductible. Among those who knew of their deductible, half anticipated that it would cause them to delay or avoid medical care, including avoiding doctor's office visits and medical tests, even services that they believed were medically necessary. Many expressed concern about their costs, anticipating the inability to afford care and expressing the desire to change plans.</p> <p>Conclusion</p> <p>Early in their experience with a deductible, patients had limited awareness of the deductible and little knowledge of the details. Many who knew of the deductible reported that it would cause them to delay or avoid seeking care and were concerned about their healthcare costs.</p

Simultaneous identification of Chlamydia trachomatis, Neisseria gonorrhoeae, Mycoplasma genitalium, and Trichomonas vaginalis ‒ multicenter evaluation of the Alinity m STI assay

Abstract Objectives Accurate and rapid diagnosis of sexually transmitted infections (STIs) is essential for timely administration of appropriate treatment and reducing the spread of the disease. We examined the performance of the new Alinity m STI assay, a qualitative real-time multiplex PCR test for simultaneous identification of Chlamydia trachomatis (CT), Neisseria gonorrhoeae (NG), Mycoplasma genitalium (MG), and Trichomonas vaginalis (TV) run on the fully automated Alinity m platform. Methods This international, multicenter study evaluated the accuracy, reproducibility, and clinical performance of the Alinity m STI assay compared to commonly used STI assays in a large series of patient samples encountered in clinical practice. Results The Alinity m STI assay identified accurately and precisely single and mixed pathogens from an analytical panel of specimens. The Alinity m STI assay demonstrated high overall agreement rates with comparator STI assays (99.6% for CT [n=2,127], 99.2% for NG [n=2,160], 97.1% for MG [n=491], and 99.4% for TV [n=313]). Conclusions The newly developed Alinity m STI assay accurately detects the 4 sexually transmitted target pathogens in various collection devices across clinically relevant specimen types, regardless of single or mixed infection status

Oral insulin immunotherapy in children at risk for type 1 diabetes in a randomised controlled trial

AIMS/HYPOTHESIS Oral administration of antigen can induce immunological tolerance. Insulin is a key autoantigen in childhood type 1 diabetes. Here, oral insulin was given as antigen-specific immunotherapy before the onset of autoimmunity in children from age 6~months to assess its safety and immune response actions on immunity and the gut microbiome. METHODS A phase I/II randomised controlled trial was performed in a single clinical study centre in Germany. Participants were 44 islet autoantibody-negative children aged 6~months to 2.99~years who had a first-degree relative with type 1 diabetes and a susceptible HLA DR4-DQ8-containing genotype. Children were randomised 1:1 to daily oral insulin (7.5~mg with dose escalation to 67.5~mg) or placebo for 12~months using a web-based computer system. The primary outcome was immune efficacy pre-specified as induction of antibody or T cell responses to insulin and measured in a central treatment-blinded laboratory. RESULTS Randomisation was performed in 44 children. One child in the placebo group was withdrawn after the first study visit and data from 22 insulin-treated and 21 placebo-treated children were analysed. Oral insulin was well tolerated with no changes in metabolic variables. Immune responses to insulin were observed in children who received both insulin (54.5%) and placebo (66.7%), and the trial did not demonstrate an effect on its primary outcome (p = 0.54). In exploratory analyses, there was preliminary evidence that the immune response and gut microbiome were modified by the INS genotype Among children with the type 1 diabetes-susceptible INS genotype (n = 22), antibody responses to insulin were more frequent in insulin-treated (72.7%) as compared with placebo-treated children (18.2%; p = 0.03). T cell responses to insulin were modified by treatment-independent inflammatory episodes. CONCLUSIONS/INTERPRETATION The study demonstrated that oral insulin immunotherapy in young genetically at-risk children was safe, but was not associated with an immune response as predefined in the trial primary outcome. Exploratory analyses suggested that antibody responses to oral insulin may occur in children with a susceptible INS genotype, and that inflammatory episodes may promote the activation of insulin-responsive T cells. TRIAL REGISTRATION Clinicaltrials.gov NCT02547519 FUNDING: The main funding source was the German Center for Diabetes Research (DZD e.V.)

Improved molecular laboratory productivity by consolidation of testing on the new random-access analyzer Alinity m

Abstract Objectives Automated molecular analyzers have accelerated diagnosis, allowing earlier intervention and better patient follow-up. A recently developed completely automated molecular analyzer, Alinity™ m (Abbott), offers consolidated, continuous, and random-access testing that may improve molecular laboratory workflow. Methods An international, multicenter study compared laboratory workflow metrics across various routine analyzers and Alinity m utilizing assays for human immunodeficiency virus type 1 (HIV-1), hepatitis C virus (HCV), hepatitis B virus (HBV), high-risk human papillomavirus (HR HPV), and sexually transmitted infection (STI) (Chlamydia trachomatis [CT]/Neisseria gonorrhoeae [NG]/Trichomonas vaginalis [TV]/Mycoplasma genitalium [MG]). Three turnaround times (TATs) were assessed: total TAT (sample arrival to result), sample onboard TAT (sample loading and test starting to result), and processing TAT (sample aspiration to result). Results Total TAT was reduced from days with routine analyzers to hours with Alinity m, independent of requested assays. Sample onboard TATs for standard workflow using routine analyzers ranged from 7 to 32.5 h compared to 2.75–6 h for Alinity m. The mean sample onboard TAT for STAT samples on Alinity m was 2.36 h (±0.19 h). Processing TATs for Alinity m were independent of the combination of assays, with 100% of results reported within 117 min. Conclusions The consolidated, continuous, random-access workflow of Alinity m reduces TATs across various assays and is expected to improve both laboratory operational efficiency and patient care