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PubMed2006

[Diagnostic performance of specific IgM detection and genomic amplification in rubella].

Nowadays, most exanthematic diseases for which a vaccine is available affect young adults. A large percentage of these cases prove to be rubella. The aim of this study is to assess the performance of specific IgM and RT-PCR for the diagnosis of rubella infection. Fifty-nine patients with clinically suspected measles or rubella, and with available serum, whole blood, urine and pharyngeal exudate specimens were studied. RT-PCR in pharyngeal exudate was found to be the most effective marker at the start of the disease (mean, 2.5 days). IgM detection yielded a larger percentage of positive results (76.2%), but at a later time (3.7 days).

Adolescent↗
PubMed2003

[Diagnostic performance of echocardiography in the follow-up of patients with toxic oil syndrome].

INTRODUCTION AND OBJECTIVES: Toxic oil syndrome is an epidemic, multisystemic disease that appeared in Spain in 1981, and was caused by the consumption of rapeseed oil denatured with 2% aniline. The disease is similar to eosinophilia-myalgia syndrome. One of the cardiovascular disorders caused by this syndrome is pulmonary hypertension. We conducted a study to assess the validity of our indications for echocardiography in the follow-up of cardiovascular disorders in patients with this disease. PATIENTS AND METHOD: These patients are followed at our center with a standardized protocol for annual check-ups. From December 1997 through July 2002, a total of 1993 patients were examined. In this period we performed a total of 487 echocardiographic studies in 424 patients. The clinical records were reviewed to assess the indications for echocardiography according to the most recent guidelines for the clinical application of echocardiography of the American College of Cardiology and American Heart Association, and the indications were grouped into several categories. The diagnosis was recorded from the cardiologist's reports at the hospital where echocardiography was done. We calculated the sensitivity, specificity and positive likelihood ratio. RESULTS: 67% of the echocardiographic examinations were indicated to investigate possible pulmonary hypertension. About one-tenth of the studies (476 studies, 9.9%) led to a diagnosis of pulmonary hypertension. Sensitivity was highest (83%) for suspected pulmonary hypertension. Specificity was very high for most of the other indications. CONCLUSIONS: This study does not allow us to draw general conclusions about the cardiovascular disorders associated with toxic oil syndrome. However, echocardiography appears to be a good follow-up technique to diagnose complications such as pulmonary hypertension in these patients.

Brassica rapa↗
PubMed2001

Community-acquired pneumonia in children due to Mycoplasma pneumoniae: diagnostic performance of a seminested 16S rDNA-PCR.

A 16S rDNA-PCR assay for Mycoplasma pneumoniae applied to nasopharyngeal secretion (NPS) or pharyngeal swab (PS) from children with community-acquired pneumonia (CAP) was prospectively compared to serological tests including complement fixation (CF) test, a mu-capture enzyme immuno assay (EIA) for the detection of specific IgM, and an EIA for the detection of specific IgG. During a 24-months-period diagnosis of active M. pneumoniae infection was established in 32 (12.6%) of 253 patients for whom paired sera were available. In the acute phase, the sensitivities of PCR from NPS and PS, CF test, IgM EIA, and IgG EIA were 90.0%, 79.3%, 46.9%, 78.1%, and 59.4%, respectively. The corresponding specificities were 98.1%, 98.6%, 97.6%, 87.1%, and 72.4%, respectively. Thus, the 16S rDNA-PCR assay provides a highly sensitive and accurate tool for the rapid diagnosis of M. pneumoniae infection in children with CAP.

Adolescent↗
PubMedDate not supplied

Diagnostic performance of myocardial contrast echocardiography for detection of stunned myocardium.

Improvement in regional wall motion after acute myocardial infarction has been described up to 2 to 3 weeks after the acute event despite restoration of blood flow by early successful reperfusion therapy. The prospective identification of potentially reversible ventricular dysfunction caused by stunned myocardium has significant clinical implications. Twenty-seven patients with acute myocardial infarction underwent myocardial contrast echocardiography (MCE) before, immediately after, and 4 weeks after successful reperfusion therapy. MCE was performed by imaging a parasternal short-axis view during intracoronary arterial injection of 2 ml sonicated ioxaglate (Hexabrix-320). The contrast defect area and contrast-filled area before reperfusion were defined as the risk area and noninfarct area, respectively. The normalized gray level was defined as the ratio of the gray level in the risk area/gray level in the noninfarct area. In 21 patients, wall motion was akinetic or dyskinetic immediately after reperfusion, and 10 of 21 patients in whom wall motion recovered during the chronic stage were defined as patients with stunned myocardium. In patients who showed asynergic wall motion immediately after reperfusion, MCE predicted the recovery of left ventricular wall motion (stunned myocardium) during the chronic stage with a sensitivity of 77%, specificity of 100%, and predictive accuracy of 86%, when a normalized gray level of more than 0.4 was presumed to predict stunned myocardium. We conclude that MCE provided the prospective identification of potentially reversible ventricular dysfunction caused by stunned myocardium, and wall motion in the area of nonenhanced myocardium on MCE immediately after reperfusion is not expected to show reversible dysfunction.

Adult↗
PubMed2003

Imaging evaluation of sinusitis: diagnostic performance and impact on health outcome.

Sinusitis is a highly prevalent disease, with a significant impact on the health care economy. Sinus CT is the primary imaging modality for evaluation of acute and chronic sinusitis. The roles of CT for patients with sinusitis are to assist clinical diagnosis, to evaluate the extent of disease, and to provide detailed anatomy necessary for treatment planning. Although sinus CT has been criticized for lack of specificity and correlation with patients' clinical symptoms, sinus CT may provide pivotal objective information that affects treatment decisions for acute and chronic sinusitis. This article provides a clinical overview and reviews the role of imaging studies in diagnosis and treatment of sinusitis.

Adult↗
PubMed2006

Diagnostic performance and potential clinical impact of advanced care paramedic interpretation of ST-segment elevation myocardial infarction in the field.

OBJECTIVES: Most studies of pre-hospital management of ST-elevation myocardial infarction (STEMI) have involved physicians accompanying the ambulance crew, or electrocardiogram (ECG) transmission to a physician at the base hospital. We sought to determine if Advanced Care Paramedics (ACPs) could accurately identify STEMI on the pre-hospital ECG and contribute to strategies that shorten time to reperfusion. METHODS: A STEMI tool was developed to: 1) measure the accuracy of the ACPs at diagnosing STEMI; and 2) determine the potential time saved if ACPs were to independently administer thrombolytic therapy. Using registry data, we subsequently estimated the time saved by initiating thrombolytic therapy in the field compared with in-hospital administration by a physician. RESULTS: Between August 2003 and July 2004, a correct diagnosis of STEMI on the pre-hospital ECG was confirmed in 63 patients. The performance of the ACPs in identifying STEMI on the ECG resulted in a sensitivity of 95% (95% confidence interval [CI] 86%-99%), a specificity of 96% (95% CI 94%-98%), a positive predictive value (PPV) of 82% (95% CI 71%-90%), and a negative predictive value (NPV) of 99% (95% CI 97%-100%). ACP performance for appropriately using thrombolytic therapy resulted in a sensitivity of 92% (95% CI 78%-98%), a specificity of 97% (95% CI 94%-98%), a PPV of 73% (95% CI 59%-85%) and an NPV of 99% (95% CI 97%-100%). We estimated that the median time saved by ACP administration of thrombolytic therapy would have been 44 minutes. CONCLUSIONS: ACPs can be trained to accurately interpret the pre-hospital ECG for the diagnosis of STEMI. These results are important for the design of regional integrated programs aimed at reducing delays to reperfusion.

Ambulances↗
PubMed1998

Effect of different background lighting conditions on diagnostic performance of digital and film images.

OBJECTIVE: To compare the performance of a photostimulable phosphor (PSP) imaging system with radiographic film for the detection of approximal lesions under two background lighting conditions. METHODS: Bitewing exposures were made of the extracted human teeth with artificial approximal lesions using D-speed and E-speed radiographic film and a PSP imaging plate. Eight dentists rated 12 approximal surfaces in each image on a 5-point scale. Images were viewed with overhead fluorescent room lighting on and off. ROC curves were generated for each image receptor and lighting condition. Repeated measures analysis of variance ANOVA tested differences between observers, lesion size, image receptor, lighting condition. RESULTS: Mean ROC curve areas for D-speed film viewed in full ambient light scored highest (0.8030) followed by E-speed film using dark conditions (0.7386). The lowest mean curve area was found when PSP (enhanced mode) images were viewed in a dark room (0.6726). Significant differences were found between observers, lesion size, image receptor and image receptor-lesion size interaction. No significant difference was found with background lighting. CONCLUSIONS: Background lighting does not appear to effect the ability to detect artificial approximal lesions.

Analysis of Variance↗
PubMed2001

Diagnostic performance of [18F]FDG-PET and ictal [99mTc]-HMPAO SPECT in occipital lobe epilepsy.

PURPOSE: We investigated whether interictal F-18 fluorodeoxyglucose positron emission tomography ([18F]FDG-PET) or ictal [99mTc]-HMPAO single-photon emission computed tomography (SPECT) was useful to find epileptogenic zones in occipital lobe epilepsy (OLE). METHODS: We reviewed visually and quantified patterns of hypometabolism in interictal [18F]FDG-PET and those of hyperperfusion in ictal SPECT in 17 OLE patients (27 plus minus 6.8 years old; M/F, 10/7; injection time, 30 plus minus 17 s). OLE was diagnosed based on invasive electroencephalography, surgery, and postsurgical outcome (Engel class I in all at an average of 26 months after surgery). RESULTS: Epileptogenic zones were correctly localized in nine (60%) of 15 patients by interictal [18F]FDG-PET, and asymmetric indices corroborated visual diagnosis. Epileptogenic hemispheres were correctly lateralized in 14 (93%) of 15 patients on [18F]FDG-PET. Epileptogenic hemispheres were correctly lateralized in 13 (76%) of 17 patients using ictal SPECT, but localization was possible in only five (29%) patients. Interictal [18F]FDG-PET was helpful in two of the patients who showed no abnormality on magnetic resonance imaging (MRI) and no possible localization with ictal SPECT. CONCLUSIONS: In OLE, ictal SPECT was helpful in lateralization, but less helpful in localization. Interictal [18F]FDG-PET was helpful in localization or lateralization of epileptogenic zones, even in patients with ambiguous MRI or ictal SPECT findings.

Adolescent↗
PubMed2002

Diagnostic performance of a dual-chamber cardioverter defibrillator programmed with nominal settings: a European prospective study.

INTRODUCTION: Despite technologic developments, accurate discrimination of ventricular tachyarrhythmia from rapid rhythms of nonventricular origin remains a challenge. We sought to examine the sensitivity and specificity of a dual-chamber arrhythmia detection algorithm, the PARAD algorithm, incorporated in a dual-chamber implantable cardioverter defibrillator, the Defender (ELA Medical). METHODS AND RESULTS: All detailed tachycardia episodes (i.e., with stored atrial and ventricular channel markers and electrograms) retrieved from the Holter memory of the device were analyzed from 95 patients (86 men and 9 women; age 62 +/- 12 years) implanted with the Defender with the algorithm programmed at nominal settings. Over a follow-up of 15 +/- 8 months, 559 detailed sustained tachycardia episodes detected in the tachycardia zone were gathered in 62 patients. Of the 300 ventricular tachycardia (VT) episodes, 298 were appropriately classified as VT by the algorithm. Of the 259 supraventricular tachycardia (SVT) episodes, 231 were appropriately classified as SVT. In 8 patients, 28 episodes of SVT were misclassified as VT: 25 atrial fibrillation episodes (6 patients), 2 sinus tachycardia (1 patient), and 1 atrial tachycardia. Calculated sensitivity and specificity were 99.3% and 89.2% on a per episode basis and 99.8% (95% confidence interval: 97.8 to 100) and 91.6% (95% confidence interval: 86.0 to 97.3) on a per patient basis, respectively. CONCLUSION: In this selected population of patients, the PARAD algorithm was safe and reliable for detection of a wide spectrum of tachyarrhythmias. Its specificity was high, particularly with respect to sinus tachycardia detection, but it must be improved with respect to detection of atrial fibrillation.

Adult↗
PubMed1991

The diagnostic performance of computer programs for the interpretation of electrocardiograms.

BACKGROUND: Computer programs for the interpretation of electrocardiograms (ECGs) are now widely used. However, a systematic assessment of various computer programs for the interpretation of ECGs has not been performed. METHODS: We undertook a large international study to compare the performance of nine electrocardiographic computer programs with that of eight cardiologists in interpreting ECGs in 1220 clinically validated cases of various cardiac disorders. ECGs from the following groups were included in the sample: control patients (n = 382); patients with left ventricular hypertrophy (n = 183), right ventricular hypertrophy (n = 55), or biventricular hypertrophy (n = 53); patients with anterior myocardial infarction (n = 170), inferior myocardial infarction (n = 273), or combined myocardial infarction (n = 73); and patients with combined infarction and hypertrophy (n = 31). The interpretations of the computer programs and the cardiologists were compared with the clinical diagnoses made independently of the ECGs, and the computer interpretations were compared with those of the cardiologists. RESULTS: The percentage of ECGs correctly classified by the computer programs (median, 91.3 percent) was lower than that of the cardiologists (median, 96.0 percent; P less than 0.01). The median sensitivity of the computer programs was also significantly lower than that of the cardiologists in diagnosing left ventricular hypertrophy (56.6 percent vs. 63.9 percent, P less than 0.02), right ventricular hypertrophy (31.8 percent vs. 46.6 percent, P less than 0.01), anterior myocardial infarction (77.1 percent vs. 84.9 percent, P less than 0.001), and inferior myocardial infarction (58.8 percent vs. 71.7 percent, P less than 0.0001). The median total accuracy level (the percentage of correct classifications) was 6.6 percent lower for the computer programs (69.7 percent) than for the cardiologists (76.3 percent; P less than 0.001). However, the performance of the best programs nearly matched that of the most accurate cardiologists. CONCLUSIONS: Our study shows that some but not all computer programs for the interpretation of ECGs perform almost as well as cardiologists in identifying seven major cardiac disorders.

Cardiology↗
PubMed2001

Comparison of diagnostic performance of cardiac troponin I on the IMMULITE system with other automated troponin I assays in minor myocardial damage.

An analytical and clinical evaluation of cardiac troponin I (cTnI) on the IMMULITE system is presented. The assay results were compared with those of the Stratus II and the Dimension RxL-HM. A between-run imprecision CV < 20% was found at a cTnI concentration of 0.23 microg/L (functional limit of detection). On the basis of a reference study including 215 patients without ischemic heart disease (97.5th percentile: 0.294 microg/L) and 36 patients clinically classified as having stable angina pectoris (<0.22 microg/L) a preliminary cutoff level of 0.3 microg/L was defined. Assay linearity, sample stability, influence of sample material and method comparison studies were performed. In patients with Duchenne's disease, chronic hemodialysis treatment, pulmonary embolism, coronary artery bypass surgery and minimally cardiac surgery the cTnI results of the IMMULITE agreed better with the Dimension RxL-HM than with the Stratus II data. Of 142 samples from patients with unstable angina 67 samples were classified as cTnI positive with the IMMULITE, 76 with the Dimension RxL-HM, and 62 with the Stratus II. In conclusion, the new assay is sensitive for the determination of cTnI and easy to perform within 45 min.

Adult↗
PubMed2004

A model of in-vivo hydrocephalus shunt dynamics for blockage and performance diagnostics.

The accumulation of excess cerebrospinal fluid in the ventricles of the brain results in hydrocephalus, a condition that is fatal if left untreated. The usual remedy is to insert a shunt into the ventricles of the brain, which drains excess fluid away, moderated by a pressure dependent valve. It is important that the system functions properly so that a reasonable intracranial pressure is maintained. Unfortunately, pressure measurements in the ventricles are highly invasive, while pressure measurements in the shunt outside the skull may not detect any blockage in the catheter inside. Here we develop a model primarily aimed at detecting in vivo a blockage and other shunt malfunction using non-invasive measurements, so that shunt valves can be adjusted accordingly. The system offers a clear insight into how currently available clinical measurements may be utilized. We then extend this to investigate the phenomenon of 'chatter' (rapid opening and closing) and other mechanisms including intracranial pressure pulsatility. Although simple, the model offers a clear indication of what is required for successful regulation of both intracranial pressure and shunt flow.

Cerebral Ventricles↗
PubMed2002

Determinants of diagnostic performance of [F-18]fluorodeoxyglucose positron emission tomography for axillary staging in breast cancer.

OBJECTIVE: To prospectively investigate determinants of the accuracy of staging axillary lymph nodes in breast cancer using [F-18]fluorodeoxyglucose positron emission tomography (FDG PET). METHODS: Patients with primary operable breast cancer underwent FDG PET of the chest followed by sentinel node biopsy (SNB, n = 47) and/or complete axillary lymph node dissection (ALND, n = 23). PET scans were independently interpreted by three observers in a blinded fashion with respect to the FDG avidity of the primary tumor and the axillary status. The results were compared to histopathological analyses of the axillary lymph nodes. Clinicians were blinded to the PET results. RESULTS: Axillary lymph node specimens and FDG PET scans were evaluated in 70 patients (59% cT1). Overall, 32 (46%) had lymph node metastases as established by SNB (18/47) or ALND (14/23), 20 of which were confined to a single node. The overall sensitivity of FDG PET was 25%, with a specificity of 97%. PET results were false-negative in all 18 positive SNBs and true-positive in 8/14 in the ALND group. The performance of FDG PET depended on the axillary tumor load and the FDG avidity of the primary tumor. Intense uptake in the primary tumor was found in only 57% of the patients, and this was independent of the size. There was excellent interobserver agreement of visual assessment of FDG uptake in primary tumor and axillary lymph nodes. CONCLUSIONS: The sensitivity of FDG PET to detect occult axillary metastases in operable breast cancer was low, and it was a function of axillary tumor load and FDG avidity of the primary tumor. Even though the clinical relevance of occult disease detected by SNB needs to be confirmed, it is suggested that FDG PET in these patients should be focused on exploiting its nearly perfect specificity and the potential prognostic relevance of variable FDG uptake.

Axilla↗
PubMed1996

Further evidence of the relationship between case typicality and diagnostic performance: implications for medical education.

We have produced further evidence demonstrating that DDx performance is a function of a test case's typicality. Medical educators might consider exploring how cognitive scientists have used the typicality assumption to investigate and enhance the instruction and assessment of subjects engaged in other classification tasks. Further substantiation of the applicability and utility of the assumptions making up the abstraction and exemplar theories used to explain DDx performance could serve as the basis for effective and efficient curricular reforms in medical education.

Artificial Intelligence↗