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By analyzing quite a number of studies a correlation between some parameters in making X-ray diagnoses, X-ray emitters and converters is determined. From this, a new optimum duty cycle for the X-ray diagnostic generator, securing a maximum diagnostic value and examination effectiveness of a high degree automation and reliability of the system may be suggested.
OBJECTIVES: Using decision analysis, to compare the expected utility (EU) of diagnostic peritoneal lavage (DPL), computed tomography (CT), and ultrasonography (US) to determine the optimal modality for the evaluation of blunt abdominal trauma (BAT) in hemodynamically stable adults. METHODS: Data points for the decision analysis were obtained from three sources: 1) prevalence of BAT and the sensitivity and specificity of each diagnostic modality were determined through a criteria-based review of the literature; 2) rate of BAT necessitating immediate intervention, perioperative complication rate, and operative mortality rate were calculated using data from the authors' institution's trauma registry; and 3) outcome utilities were determined by telephone survey of adults in a random sample of households in the region. The decision tree was constructed and evaluated in standard fashion. For each diagnostic modality, the authors calculated the EU using the minimum, mean, and maximum sensitivity and specificity across a range of prevalence. Mean outcome utilities were used for each branch of the tree when calculating the EU. RESULTS: The EU of CT was consistently lower than the EUs of DPL and US at all levels of prevalence. However, the rank order of the EUs of US and DPL varied with the prevalence of BAT. When the prevalence was <30%, the EU of US was higher than that for DPL. When the prevalence was 30-40%, the EUs were similar. When the prevalence was >40%, the EU of US was less than that of DPL. CONCLUSIONS: Among institutions operating under constraints similar to those used in this model, the optimal diagnostic modality for the evaluation of BAT can be determined based on the sensitivity and specificity of the modality at their institution and the prevalence of BAT in their patient population.
Mammography as a priority method of diagnosis of breast nodules in young women is of low efficacy as a result of a dense background of the breast as distinct from echography permitting the detection of abnormal lesion against this background. Altogether 126 patients with clinical manifestations of breast nodules were investigated. Apparatus methods used for investigation of 38 of them, revealed but manifestations of fibrocystic mastopathy. Assessment of the efficacy of x-ray and ultrasound diagnostic methods was performed in 88 patients with breast nodules (the patients varied in age from 14 to 40). Radiodiagnostic accuracy in benign tumors was 54.1%, that in malignant tumors--78.1%. Ultrasound investigation proved to be the most informative method for diagnosis of breast nodules in young women, and the use of a proposed algorithm would permit optimization of the diagnostic process.
Mammography as a priority method of diagnosis of breast nodules in young women is of low efficacy as a result of a dense background of the breast as distinct from echography permitting the detection of abnormal lesion against this background. Altogether 126 patients with clinical manifestations of breast nodules were investigated. Apparatus methods used for investigation of 38 of them, revealed but manifestations of fibrocystic mastopathy. Assessment of the efficacy of x-ray and ultrasound diagnostic methods was performed in 88 patients with breast nodules (the patients varied in age from 14 to 40). Radiodiagnostic accuracy in benign tumors was 54.1% that in malignant tumors--78.1%. Ultrasound investigation proved to be the most informative method for diagnosis of breast nodules in young women, and the use of a proposed algorithm would permit optimization of the diagnostic process.
The diagnosis of ventilator-associated pneumonia (VAP) is problematic despite numerous attempts at defining acceptable diagnostic criteria and the optimal technique for routine respiratory sampling. Clinical criteria have imperfect diagnostic reliability in ventilated patients, but remain crucial for defining those patients who may require respiratory sampling. Quantitative clinical scoring systems may improve the accuracy of clinical diagnosis in some ventilated patients. Review of published studies suggest that fibreoptic bronchoscopic techniques have greater diagnostic reliability than qualitative endotracheal aspirates, despite inconsistent results when comparing the same techniques in different centres. However, the cost and invasive nature of bronchoscopic methods precludes their use as first-line techniques in VAP. Non-bronchoscopic, non-directed techniques are cheaper, safer and more widely available alternatives to fibreoptic bronchoscopy techniques and have comparable accuracy. Quantitation of respiratory tract cultures is useful in excluding VAP in patients with equivocal signs of pneumonia. The diagnostic threshold of bacterial load that defines the presence of VAP should vary according to the pre-test probability of pneumonia, length of ventilation, antibiotic administration and immunocompetence of the patient.
Planning and scheduling of radiologic exams represent one of the crucial aspects in the performance of Diagnostic Imaging service, whose optimal management should lead to optimal efficiency and exploitation of technological and professional resources. A Diagnostic Imaging service with agreed and scheduled exams for customers achieves a more adequate, precise planning of the activity with optimum productivity of radiology rooms and anticipated workload assessment.
PURPOSE: To determine the effects on the accuracy of staging prostate gland cancer of diagnostic prediction rules based on demographic, clinical, histologic, and magnetic resonance (MR) image variables. MATERIALS AND METHODS: A total of 200 cases from four medical centers were evaluated by nine radiologists experienced in MR imaging. The accuracies of the four diagnostic variables (age, prostate specific antigen level, Gleason tumor grade, and MR imaging findings) were measured, both singly and combined in a particular sequence, by calculating the area index of the receiver operating characteristic curve. RESULTS: The accuracy of staging with single variables (age, 0.58; prostate specific antigen level, 0.74; Gleason grade 0.73, MR image findings, 0.74) increased as the variables were optimally merged. The first two variables combined to yield an accuracy of 0.74; the first three combined to yield an accuracy of 0.81; and all four variables resulted in an accuracy of 0.86. In a clinically important subset of 69 cases for which antigen level and Gleason grade together were inconclusive for the purposes of staging, the addition of MR imaging findings resulted in an increase in accuracy from 0.55 to 0.73. CONCLUSION: Optimal merging of diagnostic test results yields an improvement in the accuracy of prostate cancer staging.
The aim of this study was to evaluate temporomandibular joint radiographs of children in primary dentition, obtained by conventional transcranial radiography, indirect digitization, digitized images using 3D and brightness/contrast tools. Condyle position was also determined measuring anterior, superior and posterior joint space. The X-Ray machine GE-1000 and the head positioner Accurad 200 were used. Radiographs were digitized using a scanner with transparency and registered in Adobe Photoshop 5.0. Images were evaluated by four examiners as follows: 0--unacceptably quality; 1--poorly diagnostic quality; 2--optimal visualization quality. Articular space was measured using a digital caliper. A significant difference (Sign Test) was found between conventional radiography and the remaining modalities (Conventional/Unenhanced p<0.001; Conventional/3D p<0.001; Conventional/Brightness and Contrast p=0.017). The mean distance of anterior, superior and posterior regions was 2.2(0.5), 3.5(0.9) and 3.9(1.2) mm, respectively. Conventional and brightness/contrast digitized radiographs showed higher diagnostic quality. The posterior joint space was larger than the anterior one, demonstrating anterior condylar position.
UNLABELLED: Metagenomic next-generation sequencing (mNGS) is a promising tool for diagnosing challenging infections like tuberculosis (TB). However, previous studies largely focused on case-specific application of mNGS in TB diagnosis. Thus, we conducted a retrospective observational study to first systematically evaluate the diagnostic performance and cost-effectiveness of mNGS for TB diagnosis. We retrieved a total of 16,776 results of the seven TB diagnostic assays, including mNGS, tuberculosis IgG antibody, TB interferon-γ release assay (TB-IGRA), TB-DNA, Xpert MTB/RIF (Xpert), culture, and acid-fast bacilli staining (AFS) from 3,757 participants with suspected TB infection at Sichuan Provincial People's Hospital from September 2021 to July 2024. Diagnostic metrics were compared against a composite reference standard. Microbial composition and a cost-utility analysis were performed. Among seven TB assays studied, the World Health Organization (WHO)-recommended assays AFS, culture, and Xpert, as well as TB-IGRA, were requested most frequently for TB diagnosis, whereas mNGS ranked last. mNGS demonstrated the highest specificity (100%), accuracy (72.3%), and area under the curve (AUC) (0.795). Its sensitivity in bronchoalveolar lavage fluid and tissue was 71.0% and 72.7%, respectively. Sequential use of mNGS after initial WHO-recommended tests (Xpert/Culture/AFS) significantly improved diagnostic performance (sensitivity, 70.4%; AUC, 0.823). Microbial analysis associated Candida albicans with TB. Cost-utility analysis showed sequential mNGS became cost-effective at higher willingness-to-pay thresholds (>200,000 RMB per correct diagnosis). mNGS offers superior specificity for TB diagnosis. A sequential strategy applying mNGS to conventional-test-negative cases provides enhanced diagnostic performance and is cost-effective at higher healthcare investment values, supporting its utility for diagnostically challenging TB. IMPORTANCE: This study systematically assesses the diagnostic performance and cost utility of metagenomic next-generation sequencing (mNGS) for tuberculosis (TB) in a large real-world cohort of 3,757 suspected patients, comparing it against six conventional assays (tuberculosis IgG antibody, TB interferon-γ release assay, TB-DNA, Xpert, culture, and acid-fast bacilli staining). mNGS demonstrated the highest specificity (100%), accuracy (72.3%), and area under the curve (AUC) (0.795), with sensitivities of 71.0% in bronchoalveolar lavage fluid and 72.7% in tissue. Notably, sequential use of mNGS after the World Health Organization-recommended tests significantly improved sensitivity to 70.4% and AUC to 0.823. Candida albicans showed significant differences among the three groups. The sequential mNGS strategy was cost-effective compared with no mNGS, and its cost-effectiveness increased with a rising willingness-to-pay threshold. Overall, these results highlight mNGS as a valuable supplementary tool for challenging TB cases, especially when conventional tests are inconclusive, and provide strong evidence for integrating it into diagnostic algorithms to optimize clinical decision-making and resource allocation.
Computerized information systems that support medical decision-making are based upon formalized medical knowledge. Therefore, appropriate methods of knowledge engineering are of conspicuous importance. In order to arrive at a medical-history expert system, a target-oriented construction method of knowledge engineering was devised. Beginning with a framework of diagnostic categories, an optimal set of reliable and valid questions were formulated. In this paper, two independently developed general medicine questionnaires prepared by such a method are comparatively presented. It is shown that (a) inspite of a good deal of similarity between the two frames of reference considerable differences exist between the two sets of selected questions, and (b) the valid collection of medical information is limited to diagnostic categories that allow a clear description of medical symptoms.
In this study, the contact-hysteroscopic findings are compared with the histopathological diagnosis of 168 patients who were treated for post-menopausal bleedings. The good diagnostic agreement between contact-hysteroscopy and histopathology in mostly benign alterations like atrophic endometrium (94.7%), polyposis (87.5%), mucosal polyps (88%) and myomas (100%) is not achieved in precancerous (77%) and cancerous (75%) lesions. Being an optical method, contact hysteroscopy necessarily fails in the evaluation of origin, dignity and degree of differentiation of malign lesions, and is no substitute for a histopathological diagnosis. Therefore, contact hysteroscopy may only provide additional information to dilatation and curettage and thus optimize results and diagnostic security.
BACKGROUND: Since the clinical diagnosis of pulmonary embolism is unreliable, various objective diagnostic methods (or combinations thereof) are advocated. Pulmonary angiography is the accepted reference method but is considered less suitable for initial screening due to its invasive nature. Therefore, at least nine different diagnostic management strategies employing invasive and noninvasive diagnostic tests are used in clinical practice. We assessed the cost-effectiveness of these strategies to help identify the optimal approach. METHODS: Based on assumptions derived from published data, we calculated mortality, morbidity, adequacy for the indication of anticoagulant therapy, and associated diagnostic and therapeutic costs using a decision analytic model. Additionally, a cost-effectiveness analysis was performed using incremental costs per additional life saved. RESULTS: The analysis identified three separate categories of diagnostic management strategies: (1) Treatment of all patients (or of those with an abnormal perfusion scan) results in the lowest mortality and morbidity rates but the highest costs due to inappropriate treatment of 55% to 70% of patients. (2) Pulmonary angiography strategies with or without prior perfusion-ventilation lung scintigraphy and ultrasonography of the legs have comparable low mortality and morbidity rates, costs savings of approximately 40%, and inappropriate treatment in fewer than 5% of patients. (3) Use of perfusion-ventilation scintigraphy with or without ultrasonography results in unacceptably high mortality rates. CONCLUSIONS: At present, the optimal diagnostic management strategy should include pulmonary angiography. Use of perfusion-ventilation lung scintigraphy and ultrasonography results in a 40% to 50% reduction in the number of patients requiring pulmonary angiography and is cost-effective.
Various decision rules have been advanced for evaluation of brain dysfunction with the Luria-Nebraska Neuropsychological Battery in a chronic schizophrenic or schizoaffective disorder psychotic population. The rules of Golden (1981a) produced the highest hit rate of 96% for identification of schizophrenics who had normal neurological examination findings as not brain damaged. Most of the psychotic profile decision rules, however, produced high false negative hit rates with known brain damaged cases. The critical level decision rules (Golden, Moses, Graber, & Berg, 1981) had the highest hit rate (76.7%) with the known brain-damaged sample. Optimal classification of diagnostic groups appeared to be facilitated by use of decision rules that were especially designed for the psychotic and brain-damaged groups, respectively.
Placental mesenchymal dysplasia (PMD) is a rare vascular placental disorder that mimics molar pregnancy but often coexists with a viable fetus, making its misdiagnosis potentially devastating. In high-risk pregnancies, artificial intelligence (AI)-enhanced multimodal modeling - incorporating imaging, genomics, proteomics, and clinical features - offers a transformative diagnostic strategy. Leveraging Bayesian hyperparameter optimization for model refinement, this approach improves diagnostic accuracy while reducing uncertainty and clinician hesitation. Recent clinical studies support its efficacy and interpretability through SHAP and LIME models, while real-time surgical enhancements using Bayesian methods highlight its broader clinical utility. Despite current challenges such as data heterogeneity and integration barriers, multimodal AI provides unprecedented resolution in placental analysis, enabling precise differentiation between PMD and similar fetopathies. Ultimately, this advancement supports timely, non-invasive diagnosis, personalized management, and emotionally informed decision-making aligned with ethical AI implementation standards.
The Windows 95/NT operating systems (Microsoft Corp, Redmond, WA) currently provide the only low-cost truly preemptive multitasking environment and as such become an attractive diagnostic workstation platform. The purpose of this project is to test and optimize display station graphical user interface (GUI) actions previously designed on the pseudomultitasking Macintosh (Apple Computer, Cupertino, CA) platform, and image data transmission using time slicing/ dynamic prioritization assignment capabilities of the new Windows platform. A diagnostic workstation in the clinical environment must process two categories of events: user interaction with the GUI through keyboard/mouse input, and transmission of incoming data files. These processes contend for central processing units (CPU) time resulting in GUI "lockout" during image transmission or delay in transmission until GUI "quiet time." WinSockets and the Transmission Control Protocol/Internet Protocal (TCP/IP) communication protocol software (Microsoft) are implemented using dynamic priority timeslicing to ensure that GUI delays at the time of Digital Imaging and Communications in Medicine (DICOM) file transfer do not exceed 1/10 second. Assignment of thread priority does not translate into an absolute fixed percentage of CPU time. Therefore, the relationship between dynamic priority assignment by the processor, and the GUI and communication application threads will be more fully investigated to optimize CPU resource allocation. These issues will be tested using 10 MB/sec Ethernet and 100 MB/sec fast and wide Ethernet transmission. Preliminary results of typical clinical files (10 to 30 MB) over Ethernet show no visually perceptible interruption of the GUI, suggesting that the new Windows PC platform may be a viable diagnostic workstation option.
RATIONALE AND OBJECTIVES: When diagnostic tests are repeated and combined, a number of schemes may be adopted. Guidelines for their interpretations are required. MATERIALS AND METHODS: Three combination schemes, "and" (A), "or" (O), and "majority" (M), are considered. To evaluate these schemes, dependency by specifying kappa values quantifying repeated test agreement was structured. In a pilot study, the combined accuracies of magnetic resonance imaging using six different pulse sequences of medial collateral ligaments of the elbows of 28 cadavers, with eight having lesions artificially created surgically, were examined. Images were evaluated simultaneously by using a five-point ordinal scale. For each pulse sequence, individuals for whom the diagnosis varied from once to three repetitions were considered. RESULTS: Scheme M improves diagnostic accuracy when sensitivity and specificity of a single test exceed 0.5, with maximal improvement at 0.79. Under scheme A, sensitivity decreases to 0.38-0.59. Under scheme O, sensitivity increases to 0.53-0.79. Scheme M yields a small improvement, reaching 0.50-0.71. Under scheme A, specificity increases to 0.95-0.98. Under scheme O, specificity decreases to 0.91-0.98. Scheme M also yields a small improvement, reaching 0.94-0.98. CONCLUSION: Scheme A is recommended for ruling in diagnoses, scheme O is recommended for ruling out diagnoses, and scheme M is neutral. Consequently, different schemes may be used to optimize the target diagnostic accuracy.
Padlock probes (PLPs) are long oligonucleotides, whose ends are complementary to adjacent target sequences. Upon hybridization to the target, the two ends are brought into contact, allowing PLP circularization by ligation. PLPs provide extremely specific target recognition, which is followed by universal amplification and microarray detection. Since target recognition is separated from downstream processing, PLPs enable the development of flexible and extendable diagnostic systems, targeting diverse organisms. To adapt padlock technology for diagnostic purposes, we optimized PLP design to ensure high specificity and eliminating ligation on non-target sequences under real-world assay conditions. We designed and tested 11 PLPs to target various plant pathogens at the genus, species and subspecies levels, and developed a prototype PLP-based plant health chip. Excellent specificity was demonstrated toward the target organisms. Assay background was determined for each hybridization using a no-target reference sample, which provided reliable and sensitive identification of positive samples. A sensitivity of 5 pg genomic DNA and a dynamic range of detection of 100 were observed. The developed multiplex diagnostic system was validated using genomic DNAs of characterized isolates and artificial mixtures thereof. The demonstrated system is adaptable to a wide variety of applications ranging from pest management to environmental microbiology.
OBJECTIVES: The aim of this study was to determine which quantitative angiographic variable best describes functional status 6 months after coronary balloon angioplasty. BACKGROUND: Several angiographic restenosis criteria have been developed. These can be divided into those that describe the change in lesion severity and those that merely describe lesion severity at follow-up angiography. The functional significance of these criteria is unknown. METHODS: We studied 350 patients with single-vessel coronary artery disease who underwent a single-site balloon dilation. Sensitivity and specificity curves were constructed for the prediction of anginal status and exercise electrocardiography of four quantitative angiographic variables that describe restenosis. The point of highest diagnostic accuracy for the variables was determined at the intersection of the sensitivity and specificity curves. Results of exercise electrocardiography were considered indicative for ischemia 6 months after angioplasty if horizontal or downsloping ST segment depression > or = 1 mm occurred. RESULTS: The points of highest diagnostic accuracy of the angiographic variables were similar for both anginal status and exercise electrocardiography: 1.45 and 1.46 mm for the minimal lumen diameter measurements, 45.5% and 46.5% for the percent diameter stenosis measurements at follow-up, -0.30 and -0.32 mm for change in minimal lumen diameter and -10% and -10% for the change in percent diameter stenosis at follow-up. CONCLUSIONS: Angiographic variables reflecting a change in lesion severity at follow-up angiography were only slightly less accurate than variables that describe lesion severity at follow-up. The large study group and the fact that the same optimal values for diagnostic accuracy of the various quantitative angiographic variables were obtained for the prediction of two different markers of ischemia suggests that these values reflect the lesion severity or increase in lesion severity in major epicardial vessels at which coronary flow reserve is unable to meet myocardial demands.