Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “diagnostic performance”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 937 records · Page 52Linked to original sources

Diagnostic pattern recognition on gene-expression profile data by using one-class classification.

In this paper, we perform diagnostic pattern recognition on a gene-expression profile data set by using one-class classification. Unlike conventional multiclass classifiers, the one-class (OC) classifier is built on one class only. For optimal performance, it accepts samples coming from the class used for training and rejects all samples from other classes. We evaluate six OC classifiers: the Gaussian model, Parzen windows, support vector data description (with two types of kernels: inner product and Gaussian), nearest neighbor data description, K-means, and PCA on three gene-expression profile data sets, those being an SRBCT data set, a Colon data set, and a Leukemia data set. Providing there is a good splitting of training and test samples and feature selection, most OC classifiers can produce high quality results. Parzen windows and support vector data description are "over-strict" in most cases, while nearest neighbor data description is "over-loose". Other classifiers are intermediate between these two extremes. The main difficulty for the OC classifier is it is difficult to obtain an optimum decision threshold if there are a limited number of training samples.

Colon↗

Diagnostic model of esophageal varices in alcoholic liver disease.

Esophageal varices may cause life-threatening bleeding with attendant high hospital cost. Since effective preventive modalities for variceal hemorrhage have been established, early detection of esophageal varices is critical for prevention of bleeding. Currently, endoscopic screening is widely recommended to patients who have the diagnosis of cirrhosis. However, the diagnosis of cirrhosis relies on histological evaluations, which is costly and invasive, and endoscopic screening also burdens medical resources. Recent cost-effectiveness studies suggested that empiric prophylaxis with beta-blockers may be viable in comparison with endoscopic screening in patients with cirrhosis. However, this issue need to be also evaluated taking account of societal and patient perspectives and is not yet decided. An accurate non-invasive diagnostic model to predict the presence of esophageal varices may reduce unnecessary endoscopic procedures and prophylactic medication and improve cost-benefit of these approaches. Use of an accurate serum marker for severe hepatic fibrosis may also improve accuracy of non-invasive diagnostic models. Hyaluronic acid, a serum marker for severe hepatic fibrosis, has been reported to have a high diagnostic performance in assessing the severity of hepatic fibrosis in patients with alcoholic liver disease. In this issue, a non-invasive diagnostic model including hyaluronic acid was shown to have excellent performance in excluding the presence of medium to large esophageal varices in severe alcohol abusers. Based on current evidence, the strategy of using a non-invasive diagnostic model together with a serum marker for severe hepatic fibrosis may improve cost-benefit in the prevention of variceal hemorrhage among patients with alcoholic liver disease. The independent verification of such diagnostic models is needed.

Biomarkers↗

Detecting acute coronary syndrome in the emergency department with cardiac magnetic resonance imaging.

BACKGROUND: Managing chest pain in the emergency department remains a challenge with current diagnostic strategies. We hypothesized that cardiac MRI could accurately identify patients with possible or probable acute coronary syndrome. METHODS AND RESULTS: The diagnostic performance of MRI was evaluated in a prospective study of 161 consecutive patients. Enrollment required 30 minutes of chest pain compatible with myocardial ischemia but an ECG not diagnostic of acute myocardial infarction. MRI was performed at rest within 12 hours of presentation and included perfusion, left ventricular function, and gadolinium-enhanced myocardial infarction detection. MRI was interpreted qualitatively but also analyzed quantitatively. The sensitivity and specificity, respectively, for detecting acute coronary syndrome were 84% and 85% by MRI, 80% and 61% by an abnormal ECG, 16% and 95% for strict ECG criteria for ischemia (ST depression or T-wave inversion), 40% and 97% for peak troponin-I, and 48% and 85% for a TIMI risk score > or =3. The MRI was more sensitive than strict ECG criteria for ischemia (P<0.001), peak troponin-I (P<0.001), and the TIMI risk score (P=0.004), and MRI was more specific than an abnormal ECG (P<0.001). Multivariate logistic regression analysis showed MRI was the strongest predictor of acute coronary syndrome and added diagnostic value over clinical parameters (P<0.001). CONCLUSIONS: Resting cardiac MRI exhibited diagnostic operating characteristics suitable for triage of patients with chest pain in the emergency department. Performed urgently to evaluate chest pain, MRI accurately detected a high fraction of patients with acute coronary syndrome, including patients with enzyme-negative unstable angina.

Acute Disease↗

Validation of the TransplantTrace cfDNA Kidney assay for measurement of donor-derived cell-free DNA in transplant recipients.

INTRODUCTION: Donor-derived cell-free DNA (dd-cfDNA) has emerged as a promising non-invasive marker for assessing allograft status and guiding clinical management in transplant recipients. Its utility in kidney transplantation has repeatedly been demonstrated in large studies showing a strong association between elevated dd-cfDNA levels and allograft injury or rejection. This study evaluated the performance of a centralized next-generation sequencing (NGS)-based assay for measurement of dd-cfDNA in patients post-kidney transplantation. METHODS: The TransplantTrace cfDNA Kidney assay utilizes 50 insertion-deletion (indel) markers to discriminate dd-cfDNA. Evaluation of analytical performance included determination of input requirements, analytical sensitivity and specificity, as well as accuracy and precision parameters. Diagnostic performance was evaluated in a retrospective cohort of 104 post-transplantation samples by comparing dd-cfDNA results with biopsy-confirmed rejection. RESULTS: The assay required low DNA input (2&#x202f;ng) and demonstrated high analytical sensitivity, with a verified limit of detection of 0.2% and limit of quantification of 0.3% dd-cfDNA. Analytical accuracy was excellent (R 2&#x202f;=&#x202f;1.00), with high repeatability and reproducibility across the reportable range of 0.2-30% dd-cfDNA. In the clinical validation, the assay showed high concordance with biopsy-confirmed rejection and excellent discriminatory performance for differentiating active from non-active rejection (AUC of 0.980). At a 1% cut-off, the assay exhibited a positive predictive value of 100%, supporting confident identification of patients likely to have treatable graft injury, while a high negative predictive value (95.6% at 15% prevalence) supports its reliability in ruling out active rejection. CONCLUSION: The TransplantTrace cfDNA Kidney assay demonstrated robust analytical performance and strong clinical concordance with biopsy-confirmed rejection status. Its high diagnostic accuracy supports reliable identification and exclusion of active rejection, with the potential to reduce reliance on invasive biopsy procedures in patients with elevated serum creatinine but low dd-cfDNA levels. In summary, the findings of this study support the implementation and use of this centralized assay for measurement of dd-cfDNA in patients post-kidney transplantation.

centralized↗

Digital chest imaging using a selenium detector. The impact of hard copy size on observer performance: a computed tomography-controlled study.

RATIONALE AND OBJECTIVES: The authors compare radiologist detection performance under clinical conditions for assessment of the effect of size reduction on the diagnostic performance of digital chest images obtained with a selenium detector. METHODS: Sixty-five patients were examined with the digital system. The images were acquired without an antiscatter grid. Sixty-five posteroanterior life-size images (35 x 43 cm) and sixty-five posteroanterior minified images (56% of life size) were analyzed by three observers for detection of pulmonary, mediastinal, and pleural pathology, using computed tomography as the reference standard. The diagnostic value of life-size and minified images for the detection of these chest abnormalities was analyzed with receiver operating characteristic (ROC) methods. RESULTS: For the detection of the various abnormalities by all radiologists, the areas under the ROC curves with life-size images versus minified images, respectively, were as follows: pulmonary opacities, 0.78 versus 0.78; interstitial disease, 0.74 versus 0.75; mediastinal disease, 0.70 versus 0.72; and pleural abnormalities 0.72 versus 0.67. CONCLUSIONS: There was no statistically significant difference between the radiologists' performance in detecting pulmonary, mediastinal, and pleural pathology with life-size versus that with minified (56% of life size) digital selenium chest radiography.

Adolescent↗

Effect of ultrasonography and optional computed tomography on the outcome of appendectomy.

The aim of this study was to investigate the value of US and complementary CT in patients with suspected appendicitis, and to detect adverse outcomes of preoperative imaging. We retrospectively reviewed the data of 233 consecutive patients who underwent an appendectomy as an emergency procedure in our hospital, within a 2-year period. Our hospital policy is to perform diagnostic imaging in all patients with clinical suspicion of appendicitis. The US was performed in 227 patients, followed by additional unenhanced helical focused appendiceal CT in 30 patients with equivocal US results. We evaluated the negative appendectomy rate, occurrence of perforation, and our in-hospital delay. Acute appendicitis was pathologically proven in 219 patients, corresponding to a negative appendectomy rate of 6%. The US with optional CT diagnosed appendicitis with a sensitivity of 96.7%. Forty-eight appendices (21.9%) were perforated. The median overall in-hospital delay was 5 h (range 0.5-123.5 h). For the perforated appendices this was 4.5 h (range 0.5-64.5 h), for the non-perforated appendices 6.0 h (range 0.5-123.5 h). In patients with suspected acute appendicitis, US examination with the option of additional CT significantly lowers the negative appendectomy rate as compared with the clinical acumen alone, without adverse effects on the perforation rate or the in-hospital delay.

Adolescent↗

Thinking outside the box: feline elimination.

Feline elimination problems are the leading behavioral complaint of cat owners. When presented with a feline elimination problem there are three main diagnostic categories: medical problems, marking or toileting problems. It is important to first perform diagnostic tests to rule out and/or address underlying medical issues and all feline house soiling patients should receive a comprehensive physical examination. When the elimination problem persists after a medical problem has either been ruled out or remedied, a behavioral diagnosis should be obtained. The primary distinction that must be made in a behavioral diagnosis is whether the cat is engaging in marking behavior or selecting a spot other than the litterbox for elimination (a toileting problem). The motivation for urine marking may be territorial behavior or anxiety/stress whereas toileting problems are often triggered by medical causes, aversions, preferences or anxiety. Marking animals should be neutered and additional treatment measures may include reducing conflict and stress in the environment. Drug therapy has been long used to help control urine marking and recent studies have furthered our knowledge about the most appropriate treatments. Treatment for toileting problems should focus on providing an attractive litterbox while reducing the attractiveness or accessibility of inappropriate target spots.

Animal Husbandry↗

Diagnostic accuracy of rest/stress ECG-gated Rb-82 myocardial perfusion PET: comparison with ECG-gated Tc-99m sestamibi SPECT.

BACKGROUND: Although single photon emission computed tomography (SPECT) and positron emission tomography (PET) myocardial perfusion imaging (MPI) have evolved considerably over the last decade, there is no recent comparison of diagnostic performance. This study was designed to assess relative image quality, interpretive confidence, and diagnostic accuracy by use of contemporary technology and protocols. METHODS AND RESULTS: By consensus and without clinical information, 4 experienced nuclear cardiologists interpreted 112 SPECT technetium-99m sestamibi and 112 PET rubidium-82 MPI electrocardiography (ECG)-gated rest/pharmacologic stress studies in patient populations matched by gender, body mass index, and presence and extent of coronary disease. The patients were categorized as having a low likelihood for coronary artery disease (27 in each group) or had coronary angiography within 60 days. SPECT scans were acquired on a Cardio-60 system and PET scans on an ECAT ACCEL scanner. Image quality was excellent for 78% and 79% of rest and stress PET scans, respectively, versus 62% and 62% of respective SPECT scans (both p<.05). An equal percent of PET and SPECT gated images were rated excellent in quality. Interpretations were definitely normal or abnormal for 96% of PET scans versus 81% of SPECT scans (p=.001). Diagnostic accuracy was higher for PET for both stenosis severity thresholds of 70% (89% vs 79%, p=.03) and 50% (87% vs 71%, p=.003) and was higher in men and women, in obese and nonobese patients, and for correct identification of multivessel coronary artery disease. CONCLUSION: In a large population of matched pharmacologic stress patients, myocardial perfusion PET was superior to SPECT in image quality, interpretive certainty, and diagnostic accuracy.

Aged↗

Timing of transesophageal echocardiography in diagnosing patent foramen ovale in patients supported with left ventricular assist device.

Left ventricular assist devices unload the left ventricle and decrease left atrial pressure. This hemodynamic change may cause a right to left atrial shunt and hypoxemia in patients with patent foramen ovale. We prospectively studied the best time for performing diagnostic transesophageal echocardiography in left ventricular assist device patients. Intraoperative transesophageal echocardiography was performed in 14 patients before cardiopulmonary bypass was initiated and after left ventricular assist device was implanted. No patent foramen ovale was detected when transesophageal echocardiography was done before bypass, but a patent foramen ovale was found in 3 patients when transesophageal echocardiography was performed after left ventricular assist device was activated. Patent foramen ovale was confirmed by inspection in all three patients and surgically closed during the same procedure. There were no patent foramen ovale closure-related complications.

Cardiac Surgical Procedures↗

Epigenetic regulation of HOXA2 expression affects tumor progression and predicts breast cancer patient survival.

Accumulating evidence suggests that genetic and epigenetic biomarkers hold potential for enhancing the early detection and monitoring of breast cancer (BC). Epigenetic alterations of the Homeobox A2 (HOXA2) gene have recently garnered significant attention in the clinical management of various malignancies. However, the precise role of HOXA2 in breast tumorigenesis has remained elusive. To address this point, we conducted high-throughput RNA sequencing and DNA methylation array studies on laser-microdissected human BC samples, paired with normal tissue samples. Additionally, we performed comprehensive in silico analyses using large public datasets: TCGA and METABRIC. The diagnostic performance of HOXA2 was calculated by means of receiver operator characteristic curves. Its prognostic significance was assessed through immunohistochemical studies and Kaplan-Meier Plotter database interrogation. Moreover, we explored the function of HOXA2 and its role in breast carcinogenesis through in silico, in vitro, and in vivo investigations. Our work revealed significant hypermethylation and downregulation of HOXA2 in human BC tissues. Low HOXA2 expression correlated with increased BC aggressiveness and unfavorable patient survival outcomes. Suppression of HOXA2 expression significantly heightened cell proliferation, migration, and invasion in BC cells, and promoted tumor growth in mice. Conversely, transgenic HOXA2 overexpression suppressed these cellular processes and promoted apoptosis of cancer cells. Interestingly, a strategy of pharmacological demethylation successfully restored HOXA2 expression in malignant cells, reducing their neoplastic characteristics. Bioinformatics analyses, corroborated by in vitro experimentations, unveiled a novel implication of HOXA2 in the lipid metabolism of BC. Specifically, depletion of HOXA2 leaded to a concomitantly decreased expression of PPAR&#x3b3; and its target CIDEC, a master regulator of lipid droplet (LD) accumulation, thereby resulting in reduced LD abundance in BC cells. In summary, our study identifies HOXA2 as a novel prognosis-relevant tumor suppressor in the mammary gland.

Humans↗

New method for detection of heart allograft rejection: validation of sensitivity and reliability in a rat heterotopic allograft model.

BACKGROUND: Patients with inflammatory heart muscle diseases would benefit from a safe, convenient, rapidly performed diagnostic technique with real-time results not involving tissue removal. We have performed a detailed evaluation of detection of heart allograft rejection by autofluorescence in a heterotopic abdominal rat heart allograft model ex vivo. METHODS AND RESULTS: Recipient rats with allograft (Lewis to Fisher 344; n=71) and isograft (Lewis to Lewis; n=33) hearts, treated with cyclosporine or untreated, were killed at days 2, 4, 7, 14, 21, 28, and 56 after transplant. Nontransplant controls with (n=24) or without (n=24) immunosuppressive therapy were also studied. When the rats were killed, autofluorescence spectra were acquired under blue-light excitation from midtransverse ventricular sections of native and transplanted hearts. Corresponding sections were then evaluated pathologically by a modified International Society for Heart and Lung Transplantation (ISHLT) grading schema. The spectral differences between rejecting and nonrejecting hearts were quantified by linear discriminant functions, producing scores that decreased progressively with increasing severity of tissue rejection. Mean+/-SD discriminant function scores were 2.9+/-1.6, 1.8+/-2.2, -0.1+/-2.8, -1.2+/-2.3, and -2.3+/-3.0 for isografts and allograft ISHLT grades 0, I, II, and III, respectively (Spearman rank-order correlation -0.6; P<0.001, test for trend). Cyclosporine had no detectable effect on the spectra. CONCLUSIONS: The correlation between changes in autofluorescence spectra and ISHLT rejection grade strongly supports the possibility of catheter-based, fluorescence-guided surveillance of rejection.

Animals↗

[Chronic, aortic aneurysm rupture as one reason for retrospinal back pain].

The authors present the issue of rare causes of retrospinal back pain. Particular attention has been given to abdominal aortic aneurysm--it's clinical picture, diagnostic problems and treatment modes. A retrospective evaluation of 65 operated patients was performed. Diagnostic problems in a 66-year-old patient are also presented: the final diagnosis was determined at the time of surgery, although a low back pain treatment regimen had been formerly applied to this patient. The authors emphasise the frequent occurrence of atypical clinical signs accompanying abdominal aortic aneurysm, frequent correlation with degenerative changes of the spine, and the importance of differential diagnostics in patients with atypical symptoms of low back pain.

Aged↗

A meta-analysis of the performance characteristics of the free prostate-specific antigen test.

OBJECTIVES: To conduct a meta-analysis of the diagnostic performance of the percent free prostate-specific antigen (%fPSA) test in determining prostate cancer status and to assess its value in helping to decide whether to biopsy the prostate. METHODS: Articles identified through a MEDLINE search were included if they presented adequate original primary data to calculate a receiver operating characteristic (ROC) curve in subjects possessing histopathologically verified diagnoses. Articles containing subjects with concurrent, non-prostate-related genitourinary conditions were excluded. Percent free PSA sensitivity, specificity, ROC curves, and positive likelihood ratios were calculated for all PSA ranges and for the reflex range of PSA between 4 and 10 ng/mL. RESULTS: Among the 41 studies, containing 19,643 subjects, area under the curve for %fPSA was 0.70 for all PSA levels, decreasing to 0.68 in the reflex range. A test cutoff of 20% would lead to 92% sensitivity and 23% specificity. Positive likelihood ratios ranged from 1.0 to 4.0, exceeding 2.0 at %fPSA of 15% or less. Within the reflex range, however, likelihood ratios exceeded 2.0 only at %fPSA of 7% or less. CONCLUSIONS: Percent free PSA can be a useful adjunct to PSA for primary prostate cancer screening only under certain defined situations. In the "gray zone," or reflex range, of PSA testing, %fPSA improves clinical information only when levels reach extreme values.

Blood Chemical Analysis↗

A signal-detection experiment measuring the effect of computer-aided detection on radiologists' performance.

PURPOSE: To evaluate how the specificity and sensitivity of computer-aided detection (CADe) algorithm outputs affected radiologists' diagnostic performances, the authors studied the effects of 25 simulated CADe algorithms with various sensitivities and specificities (from 60% to 100%). METHODS: Six novice radiologists read 200 images that were produced by computer and randomly displayed on CRT, and their detection performances were evaluated with receiver operating characteristic analysis. RESULTS: There were significant differences in performance among CADe types (p < 0.001). DISCUSSION AND CONCLUSION: The overall accuracy of CADe outputs is the most significant factor affecting radiologists' performances in detection and interpretation of images. There is an approximately linear relationship between the sensitivity (specificity) of the CADe output and the reader's sensitivity (specificity), and the slope of reader sensitivity (specificity) as a linear function of CADe sensitivity (specificity) can be considered to be a positive number less than unity.

Algorithms↗

Assessing rater performance without a "gold standard" using consensus theory.

This study illustrates the use of consensus theory to assess the diagnostic performances of raters and to estimate case diagnoses in the absence of a criterion or "gold" standard. A description is provided of how consensus theory "pools" information provided by raters, estimating rater competencies and differentially weighting their responses. Although the model assumes that raters respond without bias (i.e., sensitivity = specificity), a Monte Carlo simulation with 1,200 data sets shows that model estimates appear to be robust even with bias. The model is illustrated on a set of elbow radiographs, and consensus-model estimates are compared with those obtained from follow-up data. Results indicate that with high rater competencies, the model retrieves accurate estimates of competency and case diagnoses even when raters' responses are biased.

Adult↗

CAD techniques, challenges, and controversies in computed tomographic colonography.

Computer-aided diagnosis (CAD) for computed tomographic colonography (CTC) automatically detects the locations of suspicious polyps and masses on CTC and provides radiologists with a second opinion. CAD has the potential to increase radiologists' diagnostic performance in the detection of polyps and masses and to decrease variability of the diagnostic accuracy among readers without significantly increasing the reading time. Technical developments have advanced CAD substantially during the past several years, and a fundamental scheme for the detection of polyps has been established. The most recent CAD systems based on this scheme produce a clinically acceptable high sensitivity and a low false-positive rate. However, CAD for CTC is still under active development, and the technology needs to be improved further. This report describes the expected benefits, the current fundamental scheme, the key techniques used for detection of polyps and masses on CTC, the current detection performance, as well as the pitfalls, challenges, controversies, and the future of CAD.

Colonic Polyps↗

Computer interpretation of pediatric Frank vectorcardiograms in the evaluation of congenital heart disease.

The evaluation of a new computer program for analysis and interpretation of pediatric Frank vectorcardiograms is reported. The program includes extensive age- and sex-dependent criteria based on tables of limits for numerous vectorcardiographic parameters. In 728 catheterized patients, the diagnostic performance for type A statements was tested against independent and objective evidence obtained from hemodynamic and angiographic data. The overall diagnostic accuracy ranged from 75 to 89% without difference between children less than 2 years of age and those greater than or equal to 2 years of age. Sensitivities and specificities of the various diagnoses did not differ much between the 2 age groups. In the younger children, the accuracy of a positive diagnosis of left ventricular hypertrophy, right ventricular hypertrophy, and biventricular hypertrophy was 20, 15, and 32% higher, respectively, than in the older children. The accuracy of the diagnosis "normal" was 28% lower in the younger children. These differences were explained by the higher proportion of pathologic findings in the younger children: 93% versus 74% in the older children. Given the strict methods of the evaluation, the diagnostic accuracy of this pediatric program was considered clinically satisfactory. Program performance appears to be dependent not on patient age but on prevalence of abnormalities in the population analyzed. Further improvement can be expected by making the criteria more adaptable to the composition of the population.

Adolescent↗

Trained artificial neural network for glaucoma diagnosis using visual field data: a comparison with conventional algorithms.

PURPOSE: To evaluate and confirm the performance of an artificial neural network (ANN) trained to recognize glaucomatous visual field defects, and compare its diagnostic accuracy with that of other algorithms proposed for the detection of visual field loss. METHODS: SITA Standard 30-2 visual fields, from 100 glaucoma patients and 116 healthy participants, formed the data set. Our ANN was a previously described fully trained network using scored pattern deviation probability maps as input data. Its diagnostic accuracy was compared to that of the Glaucoma Hemifield Test, the Pattern Standard Deviation index at the P<5% and <1%, and also to a technique based on the recognizing clusters of significantly depressed test points. RESULTS: The included tests had early to moderate visual field loss (median MD=-6.16 dB). ANN achieved a sensitivity of 93% at a specificity level of 94% with an area under the receiver operating characteristic curve of 0.984. Glaucoma Hemifield Test attained a sensitivity of 92% at 91% specificity. Pattern Standard Deviation, with a cut off level at P<5% had a sensitivity of 89% with a specificity of 93%, whereas at P<1% the sensitivity and specificity was 72% and 97%, respectively. The cluster algorithm yielded a sensitivity of 95% and a specificity of 82%. CONCLUSIONS: The high diagnostic performance of our ANN based on refined input visual field data was confirmed in this independent sample. Its diagnostic accuracy was slightly to considerably better than that of the compared algorithms. The results indicate the large potential for ANN as an important clinical glaucoma diagnostic tool.

Adult↗