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 91 records · Page 5Linked to original sources
PubMed2006

Diagnostic performance of MRI and MR myelography in infants with a brachial plexus birth injury.

BACKGROUND: Detailed evaluation of a brachial plexus birth injury is important for treatment planning. OBJECTIVE: To determine the diagnostic performance of MRI and MR myelography in infants with a brachial plexus birth injury. MATERIALS AND METHODS: Included in the study were 31 children with perinatal brachial plexus injury who underwent surgical intervention. All patients had cervical and brachial plexus MRI. The standard of reference was the combination of intraoperative (1) surgical evaluation and (2) electrophysiological studies (motor evoked potentials, MEP, and somatosensory evoked potentials, SSEP), and (3) the evaluation of histopathological neuronal loss. MRI findings of cord lesion, pseudomeningocele, and post-traumatic neuroma were correlated with the standard of reference. Diagnostic performance characteristics including sensitivity and specificity were determined. RESULTS: From June 2001 to March 2004, 31 children (mean age 7.3 months, standard deviation 1.6 months, range 4.8-12.1 months; 19 male, 12 female) with a brachial plexus birth injury who underwent surgical intervention were enrolled. Sensitivity and specificity of an MRI finding of post-traumatic neuroma were 97% (30/31) and 100% (31/31), respectively, using the contralateral normal brachial plexus as the control. However, MRI could not determine the exact anatomic area (i.e. trunk or division) of the post-traumatic brachial plexus neuroma injury. Sensitivity and specificity for an MRI finding of pseudomeningocele in determining exiting nerve injury were 50% and 100%, respectively, using MEP, and 44% and 80%, respectively, using SSEP as the standard of reference. MRI in infants could not image well the exiting nerve roots to determine consistently the presence or absence of definite avulsion. CONCLUSION: In children younger than 18 months with brachial plexus injury, the MRI finding of pseudomeningocele has a low sensitivity and a high specificity for nerve root avulsion. MRI and MR myelography cannot image well the exiting nerve roots to determine consistently the presence or absence of avulsion of nerve roots. The MRI finding of post-traumatic neuroma has a high sensitivity and specificity in determining the side of the brachial plexus injury but cannot reveal the exact anatomic area (i.e. trunk or division) involved. The information obtained is, however, useful to the surgeon during intraoperative evaluation of spinal nerve integrity for reconstruction.

Birth Injuries↗
PubMed1998

MRI of the uterus, uterine cervix, and vagina: diagnostic performance of dynamic contrast-enhanced fast multiplanar gradient-echo imaging in comparison with fast spin-echo T2-weighted pulse imaging.

The aim of this study was to compare the diagnostic performance of contrast-enhanced fast multiplanar gradient-echo (GRE) and T2-weighted fast spin-echo (FSE) image sets in the assessment of uterus, cervix, and vagina. Fast (up to 20 contiguous sections in 23 s) multiplanar GRE and FSE images of 45 patients referred for imaging of the female pelvis were evaluated retrospectively with regard to overall image quality and the ability to detect normal anatomic structures, as well as lesion conspicuity. Results were compared with histologic findings (n = 29) or clinical follow-up. Furthermore, a quantitative assessment of contrast-to-noise ratios among normal uterine and cervical structures as well as uterine lesions was performed for both sequences. On GRE images, uterine and cervical differentiation was best seen on the image sets acquired 15 and 60 s following contrast enhancement and results were significantly better compared with delayed images (p < 0.05). Delineation of the junctional zone was significantly (p < 0.05) better on FSE compared with GRE images; no significant difference was seen for the other anatomic structures. Overall image quality of GRE and FSE images was similar. Sensitivity for lesion detection based on both GRE and FSE images was 96% with a sensitivity of 93% for GRE, and 81% for FSE images alone, respectively. Using the extended McNemar chi 2 test, the difference in diagnostic performance between FSE and GRE revealed no significant difference, whereas the combination of both techniques performed better than FSE imaging alone (p < 0.05). The presented data suggest that dynamic contrast-enhanced GRE imaging should be part of an MR examination of the female pelvis. Combined GRE and FSE imaging provide an excellent sensitivity in the assessment of uterine and vaginal pathologies.

Adolescent↗
PubMed2006

Comparison of contrast-enhanced ultrasonography versus baseline ultrasound and contrast-enhanced computed tomography in metastatic disease of the liver: diagnostic performance and confidence.

AIM: The aim of this study was to compare contrast-enhanced ultrasonography (CEUS) to baseline US and contrast-enhanced computed tomography (CT) in metastatic disease of the liver diagnosed or suspected by US during presurgical staging or postsurgical follow-up for primary malignancies. MATERIALS AND METHODS: Two hundred-fifty-three patients considered suitable for US due to the complete explorability of the liver and with one to five proven or suspected liver metastases at baseline US were included. All patients underwent US before and after microbubble injection, and multiphase contrast-enhanced CT. Independent panels of readers reviewed US and CT scans and recorded liver metastases according to a 5-grade scale of diagnostic confidence. Sensitivity, specificity (diagnostic performance) and area under the receiver operating characteristics (ROC) curve (diagnostic confidence) were calculated. RESULTS: Reference standards revealed no metastases in 57/253, more than five in 59/253, and one to five in 137/253 patients. In patients with one to five metastases, CEUS versus baseline US revealed more metastases in 64/137 and the same number in 73/137 patients while CEUS versus CT revealed more metastases in 10/137, the same number in 99/137, and lower number in 28/137. Sensitivity, specificity, and area under ROC curve of CEUS (83%, 84%, 0.929, respectively) differed from baseline US (40%, 63%, 0.579, respectively; P<0.01) while did not differ from CT (89%, 89%, 0.945, respectively; P>0.05). CONCLUSION: CEUS improved liver metastases diagnosis in comparison with baseline US while it revealed similar diagnostic performance and confidence to contrast-enhanced CT in patients considered suitable for US and with proven or suspected liver metastases at baseline US.

Aged↗
PubMed2001

Diagnostic performance of an expert system for the interpretation of myocardial perfusion SPECT studies.

UNLABELLED: An expert system (PERFEX) developed for the computer-assisted interpretation of myocardial perfusion SPECT studies is now becoming widely available. To date, a systematic validation of the diagnostic performance of this expert system for the interpretation of myocardial perfusion SPECT studies has not been reported. METHODS: To validate PERFEX's ability to detect and locate coronary artery disease (CAD), we analyzed 655 stress/rest myocardial perfusion prospective SPECT studies in patients who also underwent coronary angiography. The patient population comprised CAD patients (n = 480) and healthy volunteers (n = 175) (449 men, 206 women). Data from 461 other patient studies were used to implement and refine 253 heuristic rules that best correlated the presence and location of left ventricular myocardial perfusion defects on SPECT studies with angiographically detected CAD and with human expert visual interpretations. Myocardial perfusion defects were automatically identified as segments with counts below sex-matched normal limits. PERFEX uses the certainty of the location, size, shape, and reversibility of the perfusion defects to infer the certainty of the presence and location of CAD. The visual interpretations of tomograms and polar maps, vessel stenosis from coronary angiography, and PERFEX interpretations were all accessed automatically from databases and were used to automatically generate comparisons between diagnostic approaches. RESULTS: Using the physician's reading as a gold standard, PERFEX's sensitivity and specificity levels for detection and localization of disease were, respectively, 83% and 73% for CAD, 76% and 66% for the left anterior descending artery, 90% and 70% for the left circumflex artery, and 74% and 79% for the right coronary artery. These results were extracted from a receiver operating characteristic curve using the average optimal input certainty factor. CONCLUSION: This study shows that the diagnostic performance of PERFEX for interpreting myocardial perfusion SPECT studies is comparable with that of nuclear medicine experts in detecting and locating CAD.

Adult↗
PubMed1994

Diagnostic performance of low field MRI in acute knee injuries.

The diagnostic performance of low field (0.1 T) magnetic resonance imaging (MRI) was studied prospectively and double-blindly among 33 patients with acute knee injuries. The subsequent arthroscopy was the golden standard. For lesions of the medial meniscus low field MR had a sensitivity of 88% and a specificity of 80%; for lesions of the lateral meniscus the sensitivity was 25% and the specificity 97%. For anterior cruciate ligament tears, low field MRI had a sensitivity of 83% and a specificity of 85%. The specificity for posterior cruciate ligament tears was 97%. The performance of low field MRI equalled that reported earlier for high field MRI, the only exception being the sensitivity for lateral meniscus lesions.

Acute Disease↗
PubMed2006

Bias-corrected diagnostic performance of the naked-eye single-tube red-cell osmotic fragility test (NESTROFT): an effective screening tool for beta-thalassemia.

It is being increasingly recognized that a majority of the countries in the thalassemia-belt need a cost-effective screening program as the first step towards control of thalassemia. Although the naked eye single tube red cell osmotic fragility test (NESTROFT) has been considered to be a very effective screening tool for beta-thalassemia trait, assessment of its diagnostic performance has been affected with the reference test- and verification-bias. Here, we set out to provide estimates of sensitivity and specificity of NESTROFT corrected for these potential biases. We conducted a cross-sectional diagnostic test evaluation study using data from 1563 subjects from Central India with a high prevalence of beta-thalassemia. We used latent class modelling after ensuring its validity to account for the reference test bias and global sensitivity analysis to control the verification bias. We also compared the results of latent class modelling with those of five discriminant indexes. We observed that across a range of cut-offs for the mean corpuscular volume (MCV) and the hemoglobin A2 (HbA2) concentration the average sensitivity and specificity of NESTROFT obtained from latent class modelling was 99.8 and 83.7%, respectively. These estimates were comparable to those characterizing the diagnostic performance of HbA2, which is considered by many as the reference test to detect beta-thalassemia. After correction for the verification bias these estimates were 93.4 and 97.2%, respectively. Combined with the inexpensive and quick disposition of NESTROFT, these results strongly support its candidature as a screening tool-especially in the resource-poor and high-prevalence settings.

Adolescent↗
PubMed2005

Diagnostic performance of cardiovascular magnetic resonance in patients with suspected acute myocarditis: comparison of different approaches.

OBJECTIVES: The aim of this research was to identify the diagnostic performance of gadolinium-enhanced and T2-weighted cardiovascular magnetic resonance (CMR) in suspected acute myocarditis. BACKGROUND: Acute myocarditis is difficult to diagnose; CMR provides various means to visualize myocardial inflammatory changes. A CMR approach with clear-cut diagnostic criteria would be desirable. METHODS: We investigated 25 patients with suspected acute myocarditis (18 males, 44 +/- 17 years) and 23 healthy controls (13 males, 29 +/- 10 years). Cardiovascular magnetic resonance studies included the following sequences: 1) T2-weighted triple inversion recovery; 2) T1-weighted spin echo before and over 4 min after gadolinium injection; and 3) inversion recovery-gradient echo 10 min after gadolinium injection. Qualitative and quantitative image analysis was performed for: 1) focal and global T2 signal intensity (SI); 2) myocardial global relative enhancement (gRE); and 3) areas of late gadolinium enhancement (LGE). RESULTS: Both global T2 SI and gRE were higher in patients than in controls (T2: 2.3 +/- 0.4 vs. 1.7 +/- 0.4; p < 0.0001, gRE: 6.8 +/- 4.0 vs. 3.7 +/- 2.3; p < 0.001). The sensitivity, specificity, and diagnostic accuracy for T2 (cutoff value of 1.9) were 84%, 74%, and 79%, respectively; gRE: (cutoff value of 4.0) 80%, 68%, and 74.5% respectively; LGE: 44%, 100%, and 71%, respectively. The best diagnostic performance was obtained when "any-two" of the three sequences were positive in the same patient yielding a 76% sensitivity, 95.5% specificity, and 85% diagnostic accuracy. CONCLUSIONS: A combined CMR approach using T2-weighted imaging, early and late gadolinium enhancement, provides a high diagnostic accuracy and is a useful tool in the diagnosis and assessment of patients with suspected acute myocarditis.

Acute Disease↗
PubMed1989

[ROC: a method for comparing the diagnostic performance of imaging procedures].

ROC analysis permits an evaluation of the diagnostic performance of imaging systems by incorporating the individual decision threshold of the diagnostician that determines the relation between sensitivity and specificity of a tested system. It therefore facilitates the comparison between different imaging systems and observers. A thorough knowledge and sophistication of this methodology is of special importance in the comparison of digital and conventional projection radiography because the images in question may have a very similar character. The method is explained and special points of interest (standard of "truth", size of sample, lesion conspicuity and localisation, viewing time and determination of significance) are emphasised.

Diagnostic Imaging↗
PubMed2005

Comparative analysis of the diagnostic performance of six major Echinococcus granulosus antigens assessed in a double-blind, randomized multicenter study.

The serodiagnosis of hydatid disease is a valuable instrument for clinical diagnosis and epidemiological surveillance of high-risk populations. In the past decade a wealth of reports on the diagnostic performance of numerous antigens have been produced. However, their diagnostic value has been estimated under different conditions, using different serum collection, therefore precluding their direct comparison. Here we report an unbiased comparison of the same batch of six major E. granulosus antigens, namely, hydatid cyst fluid (HCF), native antigen B (AgB), two recombinant AgB subunits, an AgB-derived synthetic peptide, and recombinant cytosolic malate dehydrogenase from E. granulosus (EgMDH), against the same serum collection. The double-blind analysis was performed using a standardized protocol and receiver operating characteristic (ROC) data analysis by a network of six South American laboratories. High intercenter reproducibility was attained, and the intralaboratory analysis allowed the comparative ranking of the antigen panel. HCF, AgB, and its AgB8/1 subunit exhibited equivalent diagnostic efficiencies, 81.4% +/- 0.5%, 81.3% +/- 0.6%, and 81.9% +/- 2.0%, respectively; with a more favorable balance toward specificity in the case of the last antigen. The diagnostic efficiencies for the other three antigens were 76.8% +/- 6.8%, 69.1% +/- 2.7%, and 66.8% +/- 2.1%, for the peptide, the AgB8/2 subunit, and the EgMDH, respectively. The study also included an analysis of batch-to-batch variation in the diagnostic performance of different HCF regional preparations. Based on these results, a suggested recommendation on the use of these antigens was drawn.

Animals↗
PubMed1987

The effects of clinical data on radiological diagnostic performance in middle-face trauma.

To determine the effect of clinical information on the radiological diagnostic performance in middle-face injury, the medical records and radiographs of 618 patients with middle-face injury were reviewed. The information value of clinical data given in each x-ray requisition was evaluated. The radiological diagnoses were compared with the final clinical diagnoses both retrospectively and prospectively (with and without clinical data). Knowledge of clinical data with statistical significance changed the reader's decision threshold towards improved sensitivity but poorer specificity. Clinical data did not improve the radiologists' performance. Clinical data may be helpful in diagnostic tasks rather by increasing the sensitivity than the specificity.

Evaluation Studies as Topic↗
PubMedDate not supplied

Evaluation of the diagnostic performance of the Boehringer Mannheim CEDIA LSD assay.

The precision and the diagnostic performance of the Boehringer Mannheim CEDIA DAU LSD assay was evaluated. The assay was performed in the semi-quantitative mode on a Hitachi 917 analyzer. Within-run coefficients of variation (CVs) of the semiquantitative values for 0.25 and 1.0 ng/mL were 11.2 and 6.2%, respectively. Day-to-day CVs for the same concentrations were 12.6 and 8.6%. We analyzed 318 urine samples by CEDIA, DPC Coat-A-Count RIA and Behring EMIT II. Confirmation was performed by GC-MS, after extraction on Bond Elut Certify columns. Two hundred sixty-three samples were negative by all methods. Twenty-five samples were positive by all immunoassays, 19 of which were confirmed by gas chromatography-mass spectrometry (GC-MS). One sample was falsely negative by CEDIA. Three samples were positive by EMIT and CEDIA, but negative by RIA and GC-MS. Twenty-six samples were positive by EMIT alone, but they were not confirmed by GC-MS. The LSD CEDIA assay seems to be less specific than DPC RIA but more specific than the EMIT LSD assay.

Enzyme Multiplied Immunoassay Technique↗
PubMed1986

A revised schema for performing diagnostic x-ray shielding calculations.

This paper presents a method for performing diagnostic x-ray shielding calculations which is somewhat different than that given in NCRP Report No. 49. The method computes exposure at the location to be shielded from multiple sources of radiation in the room and accounts for differences in transmission characteristics of leakage and primary/scatter radiation. Also discussed in the paper is a method for determining shielding credit for existing common structural materials. Methods and results derived in the paper are then discussed and compared with NCRP Report No. 49.

Radiation Protection↗
PubMed2000

Pelvic and lower extremity arterial imaging: diagnostic performance of three-dimensional contrast-enhanced MR angiography.

OBJECTIVE: The diagnostic performance of a three-dimensional MR angiography-based strategy was assessed with regard to its ability to characterize the arterial vasculature from the aortic bifurcation to the lower extremity runoff vessels. A single-injection, two-station protocol in combination with a lower-extremity vascular coil was used. SUBJECTS AND METHODS: Both conventional digital subtraction angiography and three-dimensional contrast-enhanced MR angiography with a dedicated peripheral vascular coil were performed in 61 patients with suspected peripheral vascular disease. In a prospective analysis, one reviewer evaluated the digital subtraction angiographic images and a second reviewer evaluated the MR angiographic images; both were unaware of the results of the other imaging technique. Each vascular segment (29 segments per patient) was evaluated for the presence of occlusive vessel disease. The following grading system was applied: 0, normal; 1, vessel irregularity with a luminal reduction of less than 10%; 2, mild stenosis (lumen reduction, 10-49%); 3, severe stenosis (lumen reduction, 50-99%); and 4, occlusion (lumen reduction, 100%). In 11 patients surgical graft patency was assessed. RESULTS: MR angiography provided an image quality comparable with that of digital subtraction angiography. Overall sensitivity and specificity for MR angiography were 92% and 96.6%, respectively, for the detection of hemodynamically significant disease and 92.3% and 99.4%, respectively, for the detection of occlusions. CONCLUSION: Two-station contrast-enhanced three-dimensional MR angiography with a dedicated lower-extremity vascular coil proved effective enough to consider it as a noninvasive alternative to digital subtraction angiography in the assessment of the pelvic and lower extremity arterial vasculature.

Adult↗
PubMed2001

Deferoxamine-induced dysplasia of the knee: sonographic features and diagnostic performance compared with magnetic resonance imaging.

OBJECTIVE: To evaluate the features and diagnostic performance of sonography in the assessment of deferoxamine-induced dysplasia of the knee. METHODS: The left knees of 32 patients with thalassemia who were receiving regular blood transfusions and chelation therapy were studied with sonography for signs of deferoxamine-induced bone dysplasia. Abnormal physeal and metaphyseal changes detected on sonography included notching at the metaphyseal corner, a blurred or irregular peripheral juxtaphyseal metaphyseal contour, and widening of the peripheral juxtaphyseal metaphyseal echogenic interface. The accuracy of sonography in diagnosing dysplasia was evaluated by using magnetic resonance imaging as the standard of reference. RESULTS: There were 14 true-positive findings, 10 true-negative findings, 7 false-negative findings, and 1 false-positive sonographic diagnosis of dysplasia, giving 67% sensitivity, 91% specificity, a 93% positive predictive value, and a 59% negative predictive value. CONCLUSION: Sonography was specific but only moderately sensitive in the diagnosis of deferoxamine-induced dysplasia at the knee when compared with magnetic resonance imaging.

Adolescent↗
PubMed2003

Diagnostic performance of liquid crystal and cathode-ray-tube monitors in brain computed tomography.

The aim of this study was to evaluate feasibility of reporting brain CT examinations on liquid crystal display (LCD) flat-screen monitors vs state-of-the-art cathode-ray-tube (CRT) monitors. Ninety-five brain CT examinations of 95 patients were displayed on Picture archiving and communications system (PACS) workstations equipped either with a dedicated medical imaging LCD colour monitor or on a high-resolution CRT which is used for routine reporting of CT, MRI and digital radiography images in our institution. Fifty cases were negative and 45 cases were positive for early brain infarction (EBI), the latter being defined by a combination of one or more signs: dense artery; hypodensity of brain parenchyma; and local brain swelling verified by control scans. Ten radiologists had to rate presence or absence of EBI on a five-point scale. Ratings were evaluated by CORROC2 ROC software and areas under the ROC curve (A(z)) were computed. Significance of differences between the two viewing conditions were evaluated with Wilcoxon test. Mean A(z) of the ten observers was 0.7901 with LCD vs 0.7695 with CRT which did not show statistical significance (p=0.2030). In the setting investigated, reporting of CT studies from high-performance LCD monitors seems feasible without significant detriment to diagnostic performance.

Acute Disease↗
PubMed2001

Diagnostic performance characteristics of rapid dipstick test for Plasmodium vivax malaria.

We compared the diagnostic performance characteristics of newly developed method, the rapid dipstick test, which provides colorimetric determination by developing antibody to the lactate dehydrogenase enzyme of parasites, with conventional standard thick-blood film examination. For the rapid test, OptiMAL commercial kits were used. The results were also evaluated with clinical findings from patients. The parasites were determined by microscopic examination of thick-blood films from 81 patients with vivax malaria from southeastern Anatolia, Turkey. The OptiMAL test results were found to be negative in five patients who were diagnosed clinically and through thick-film testing as having vivax malaria. There was no false positivity observed with the OptiMAL test. We concluded that this rapid malaria test has a lower level of sensitivity than the classical thick-blood-film test for malaria, but that these methods have equal specificity.

Animals↗
PubMed2000

Comparison of measures to assess change in diagnostic performance due to a decision support system.

Little has been done to examine the relative merit of measures used to assess the impact of diagnostic decision support systems (DDSS) on physician performance. In this study, 10 different single-measures of diagnostic performance were compared empirically. The measures were of three types: rank-order, all-or-none, and appropriateness. The responsiveness (RESP) of each measure was estimated under two repeated-measures experimental conditions. RESP is the degree to which a measure could detect differences between conditions of low and high performance. The diagnostic performance of 108 physicians was compared on medical cases of varying diagnostic difficulty and with or without a high level of assistance from a DDSS. The results showed that the RESP among the measures varied nearly tenfold. The rank-order measures tended to provide the highest RESP values (maximum = 2.14) while appropriateness measures provided the lowest RESP values (maximum = 1.41). The most responsive measures were rank-orders of the correct diagnosis within the top 5 to 10 listed diagnoses.

Decision Support Systems, Clinical↗
PubMed1998

Complete analytical and diagnostic performances of the Abbott Cell Dyn 3500.

METHODS: The study reports the analytical and diagnostic performances of Cell Dyn 3500 (Abbott), an automated haematology analyser that provides the electrical impedance and the optical detection of total leukocyte and a five population leukocyte differential count. The evaluation of complete blood count and differential leukocyte count parameters was performed following the guidelines of the International Council for Standardization in Haematology and those of the National Committee for Clinical Laboratory Standards document H20-A. RESULTS: The CD 3500 demonstrated a good linearity, minimal carry-over, as well as acceptable levels of within and between-batch imprecision and stability. An excellent correlation between CD 3500 and the routine systems used in our laboratory (Technicon H*2 and Coulter STKS) was found for the major haematological indices, though agreement was not as good for MCHC. There was a good correlation between CD 3500 and manual reference differential method for neutrophils, lymphocytes, eosinophils and basophils, with the exception of monocytes. CONCLUSIONS: Regarding clinical sensitivity, the CD 3500 showed a high specificity to detect morphological abnormalities, but low sensitivity especially for the identification of immature granulocytes and nucleated red blood cells; if we overall evaluate any qualitative flags, we found an appreciable increase in sensitivity.

Autoanalysis↗