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PubMed2006

Inaccuracy of Wolff-Parkinson-white accessory pathway localization algorithms in children and patients with congenital heart defects.

INTRODUCTION: ECG algorithms used to localize accessory pathways (AP) in patients with Wolff-Parkinson-White (WPW) syndrome have been validated in adults, but less is known of their use in children, especially in patients with congenital heart disease (CHD). We hypothesize that these algorithms have low diagnostic accuracy in children and even lower in those with CHD. METHODS: Pre-excited ECGs in 43 patients with WPW and CHD (median age 5.4 years [0.9-32 years]) were evaluated and compared to 43 consecutive WPW control patients without CHD (median age 14.5 years [1.8-18 years]). Two blinded observers predicted AP location using 2 adult and 1 pediatric WPW algorithms, and a third blinded observer served as a tiebreaker. Predicted locations were compared with ablation-verified AP location to identify (a) exact match for AP location and (b) match for laterality (left-sided vs right-sided AP). RESULTS: In control children, adult algorithms were accurate in only 56% and 60%, while the pediatric algorithm was correct in 77%. In 19 patients with Ebstein's anomaly, diagnostic accuracy was similar to controls with at times an even better ability to predict laterality. In non-Ebstein's CHD, however, the algorithms were markedly worse (29% for the adult algorithms and 42% for the pediatric algorithms). A relatively large degree of interobserver variability was seen (kappa values from 0.30 to 0.58). CONCLUSIONS: Adult localization algorithms have poor diagnostic accuracy in young patients with and without CHD. Both adult and pediatric algorithms are particularly misleading in non-Ebstein's CHD patients and should be interpreted with caution.

Adolescent↗
PubMed2002

Fluorescence spectral imaging for characterization of tissue based on multivariate statistical analysis.

A novel spectral imaging method for the classification of light-induced autofluorescence spectra based on principal component analysis (PCA), a multivariate statistical analysis technique commonly used for studying the statistical characteristics of spectral data, is proposed and investigated. A set of optical spectral filters related to the diagnostically relevant principal components is proposed to process autofluorescence signals optically and generate principal component score images of the examined tissue simultaneously. A diagnostic image is then formed on the basis of an algorithm that relates the principal component scores to tissue pathology. With autofluorescence spectral data collected from nasopharyngeal tissue in vivo, a set of principal component filters was designed to process the autofluorescence signal, and the PCA-based diagnostic algorithms were developed to classify the spectral signal. Simulation results demonstrate that the proposed spectral imaging system can differentiate carcinoma lesions from normal tissue with a sensitivity of 95% and specificity of 93%. The optimal design of principal filters and the optimal selection of PCA-based algorithms were investigated to improve the diagnostic accuracy. The robustness of the spectral imaging method against noise in the autofluorescence signal was studied as well.

Algorithms↗
PubMed2002

[Diagnosis and treatment of gunshot wounds to the chest].

Experience of treatment of 86 patients with chest wounds are summarized. Diagnostic and curative algorithm of these patients are presented. Fenestration of the pericardium is proposed for diagnosis of heart wounds. This algorithm permitted to reduce early pleural complications rate from 55.1 to 22.1% and diagnostic mistakes--from 34.2 to 11.2%.

Humans↗
PubMed2003

[Diagnosis of cholestatic disorders].

BACKGROUND: Cholestasis is known as an etiologically diverse clinical entity which requires a broad differential diagnostic workup. In the majority of patients, history, clinical examination, clinical chemical analysis, and abdominal ultrasound enable the differentiation between extrahepatic and intrahepatic cholestasis. This review summarizes our current knowledge in the diagnosis of cholestatic disorders. METHODS: In regard to clinical practice, diagnostic tools and new developments in imaging and molecular genetics are discussed including an algorithm for the diagnostic workup of cholestatic patients. CONCLUSION: Ultrasound and computed tomography have represented the most important primary imaging techniques in hepatobiliary disorders over the last 2 decades. The direct visualization either by endoscopic retrograde cholangiopancreatography (ERCP) or percutaneous transhepatic cholangiography (PTC) still remains the gold standard in the evaluation of the extrahepatic bile duct. In the past decade, magnetic resonance cholangiopancreatography (MRCP) has increasingly been established as a noninvasive alternative, thereby reducing the necessity of ERCP as an invasive exploration of the biliary system. Liver biopsy is indicated for the histologic grading and staging of intrahepatic cholestatic disorders. Recently, molecular genetic studies have elucidated several mutations in genes of hepatobiliary transporters which are responsible for hereditary forms of cholestasis in man. Thus, molecular genetics may be of interest in single cases of unclassified cholestasis or familial syndromes and will contribute to the routine diagnosis of hereditary cholestatic syndromes in the future. In summary, application of these diagnostic tools will finally lead to an unequivocal diagnosis in the majority of cholestatic patients with consecutive rational therapy.

Biopsy↗
PubMed1991

DSM-IV: empirical guidelines from psychometrics.

This commentary addresses the use of psychometric theory and methodology in the development of the 4th edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV). Reliability issues include interdiagnostician reliability, temporally consistent diagnoses, and the relations of diagnostic criteria within categories. Validity issues include content validity of the diagnostic criteria, criterion-related validity (the relation between different criterion sets or their algorithms and alternative diagnostic criteria), and construct validity (the relation between diagnostic categories and external validators). Specific questions and methodology to investigate its utility vary with the different uses proposed for the diagnostic system. Specific psychometric methodologies that may be useful in developing the DSM-IV are noted, as are the limitations of psychometrics and their applicability to DSM-IV.

Humans↗
PubMedDate not supplied

[The forensic medical expertise of acute local radiation trauma].

Informative diagnostical criteria of medicolegal evaluation and prognosis of corporal lesion gravity in case of acute local radiation trauma as well as algorithm of medicolegal diagnostical process concerning these lesions with reference to external radiation exposure, kind of injuring factor, differential-diagnostical signs of acute local radiation trauma are suggested. They make it possible to formulate medicolegal diagnosis and can form the basis for developing diagnostical programmes.

Acute Disease↗
PubMed1991

[Application of fuzzy theory for optokinetic pattern test].

The optokinetic pattern test for optokinetic nystagmus is performed to diagnose equilibrium disorders on clinical examination. We constructed computer assisted instruction (CAI) algorithm based on knowledge of expert for optokinetic pattern (OKP) diagnosis theoretically based Fuzzy reasoning derived from Fuzzy theory to ascertain the possible application of CAI to OKP and to develop a useful diagnostic tool. The algorithm was constructed by rules of fuzzy reasoning using analysed data of diagnostic modes of one expert, consisting of six variables, and of 30 normal and 22 abnormal patterns of optokinetic nystagmus which were diagnosed by the expert. The results derived from the fuzzy reasoning and those obtained by expert agreed with 96% in this test battery. In addition, a consistency of 87.3% was obtained after comparison with another 251 OKP patterns which diagnosed by the same expert and estimated by this algorithm. This algorithm incorporating fuzzy theory is concluded to be useful in obtaining results of the same as those of an expert for diagnosing the equilibrium disorders. Furthermore, CAI using Fuzzy theory is confirmed to have good potential as a diagnostic tools.

Algorithms↗
PubMed2001

Recent advances in genetics, diagnosis, localization, and treatment of pheochromocytoma.

Pheochromocytoma is a rare but important tumor of chromaffin cells that is frequently considered in the evaluation of hypertension, arrhythmias, or panic disorder and in the follow-up of patients with particular genetic diseases. This report provides an update about the genetics, neurochemical diagnosis, localization by imaging, and surgical management of pheochromocytoma. Specific mutations of the RET proto-oncogene cause familial predisposition to pheochromocytoma in multiple endocrine neoplasia type II, and mutations in the von Hippel-Lindau tumor suppressor gene cause familial disposition to pheochromocytoma in von Hippel-Lindau disease. Recent findings demonstrating extraordinarily high sensitivity of plasma levels of metanephrines for detecting pheochromocytoma have led to an algorithm for clinical diagnostic steps. Nuclear imaging approaches, such as(123) I-metaiodobenzylguanidine scintigraphy and 6-[(18) F]fluorodopamine positron emission tomography, enhance both diagnosis and localization of the tumor, as described in an algorithm for patients with positive biochemical test results. Since pheochromocytoma is often benign, surgical resection by laparoscopic adrenalectomy can be curative. Areas requiring further work include determining appropriate follow-up of patients with familial pheochromocytoma, elucidating the bases for phenotypic differences, improving both specificity and sensitivity of biochemical tests, optimizing cost-effectiveness of diagnostic imaging, and testing the risk for tumor recurrence after partial adrenalectomy.

Adrenal Gland Neoplasms↗
PubMed2003

[Ectopic pregnancy: contribution of paraclinical investigations, ultrasonography excluded].

Because a misdiagnosis of ectopic pregnancy (EP) exposes patients to a vital risk, paraclinical exams have to be highly specific and as sensitive as possible. As the accuracy of diagnostic tools depends on the prevalence of the disease in different patient groups, clinical signs have to be considered when analyzing the literature (symptom-free women, complaints, risk factors...). In the first part of this review, various diagnostic tools are reviewed and the particular features of EP after assisted reproduction techniques are taken into account. The evaluation of serum quantitative betahCG level is primordial. In difficult cases when transvaginal ultrasound does not detect an intrauterine gestational sac, repeated betahCG measurements and determination of serum progesterone levels allow to evaluate the viability of an early pregnancy. If ultrasound diagnosis cannot be obtained without significant delay, culdocentesis is easy to perform and has a good positive predictive value. However, the detection of intrauterine chorionic villi is only of limited diagnostic value, whereas hysteroscopy may be of interest in some cases. In the second part an analysis of algorithms in the diagnostic management of EP is carried out. Currently, a standard protocol should not be applied for all patients and specific algorithms have to be defined according to the prevalence of EP in the treated population.

Algorithms↗
PubMed2003

The predictors of pelvic lymph node metastasis at radical retropubic prostatectomy.

PURPOSE: We studied preoperative variables in a contemporary series of patients who underwent radical retropubic prostatectomy (RRP) to determine which variables were associated with lymph node metastasis. MATERIALS AND METHODS: Between January 1995 and November 1999, 1,091 men underwent RRP, 695 of whom underwent bilateral pelvic lymph node dissection without any prior therapy. We evaluated biopsy Gleason score, maximum tumor length and maximum percentage of tumor in the positive core(s), location and number of positive cores, and total prostate specific antigen before surgery in 295 of these patients. We also developed a classification and regression tree analysis algorithm to segregate the risk of positive lymph node metastasis. Stepwise logistic regression analyses were used to determine independent predictors of lymph node metastasis. RESULTS: Of the 695 patients 19 (2.7%) had lymph node metastasis. Clinical stage, Gleason score, positive basal core, greatest percentage of tumor on positive cores and maximum tumor length in positive core were significant predictors of lymph node metastasis in the Mann-Whitney U test and chi-square test. Classification and regression trees analysis revealed that 4 or more positive cores with any Gleason grade 4 or 5, serum prostate specific antigen 15.0 ng/ml or greater, or the presence of dominant Gleason 4 or 5 were independent predictors of lymph node metastasis. Our algorithm had a significantly higher diagnostic performance than the Hamburg algorithm (p = 0.002). CONCLUSIONS: Our algorithm may be a valid tool for the prediction of lymph node metastasis and may help to select men who do not need to undergo bilateral pelvic lymph node dissection with RRP.

Adult↗
PubMed1996

A mathematical model that improves the validity of osteoarthritis diagnoses obtained from a computerized diagnostic database.

We developed an algorithm, using recursive partitioning, that utilized information from a computerized, diagnostic database to predict the diagnosis of osteoarthritis as determined by medical record review. The complete (inpatient and outpatient) medical records for a random sample of 400 Olmsted County, Minnesota residents with a database diagnosis consistent with osteoarthritis were reviewed, and confirmation or rejection of the diagnosis was accomplished. Of the 387 patients in our sample, only 232 (a positive predictive value of 60%) fulfilled diagnostic criteria for osteoarthritis following medical record review. A classification tree was created that used information from the diagnostic database to partition the study population according to the proportion of individuals with a "true" diagnosis of osteoarthritis (based on medical record review). The receiver-operating characteristic curve generated from these data illustrated that the algorithm substantially improved the validity of the database diagnosis, yielding a positive predictive value of 89% and a negative predictive value of 70% (sensitivity of 75% and specificity of 86%) at a selected cutoff point. This model also provides the capability of selecting the cutoff point to favor either specificity or sensitivity. These data demonstrate that a mathematical model can substantially improve the validity of computerized diagnostic databases in osteoarthritis.

Adult↗
PubMed2001

Imaging diagnostic approach to tumours of ramus and angle of the mandible.

The abundance of up-to-date diagnostic equipment and imaging techniques makes it necessary to reconsider diagnostic approach to many maxillofacial disorders, including mandibular tumours, and to elaborate algorithms of radiological examinations allowing for the planning of a cost-effective treatment based on thorough diagnostics. The material was composed of 146 case records of 68 patients examined in the years 1995-2000 in the Medical University of Lublin. There were selected radiograms as well as the results of other imaging modalities of persons with clinically confirmed tumours of mandibular ramus or angle. In each case there were noted: the initial and the final diagnosis as well as the number and sequence of the performed diagnostic examinations. On the basis of the obtained results there was proposed a diagnostic algorithm in cases of mandibular angle and ramus tumours, which was presented in the form of a scheme. It was proved that conventional radiograms are still fundamental in initial selection of patients while other diagnostic imaging methods are indispensable in treatment planning.

Diagnostic Imaging↗
PubMed2003

Comparison of the 80-lead body surface map to physician and to 12-lead electrocardiogram in detection of acute myocardial infarction.

Diagnosis of non-ST-elevation acute myocardial infarction (AMI) by a 12-lead electrocardiogram has poor sensitivity and specificity and, therefore, relies on biochemical markers of myocardial necrosis, which can only be reliably detected within 14 to 16 hours from symptom onset. The body surface map (BSM) improves AMI detection but is limited by its interpretation by inexperienced medical staff. To facilitate interpretation, an automated BSM algorithm was developed and is evaluated in this study. One hundred three patients with ischemic-type chest pain were recruited for this study from December 2001 to April 2002. A 12-lead electrocardiogram (Marquette Mac 5K) and BSM (PRIME-ECG) were recorded at initial presentation, and cardiac troponin I and/or creatine kinase-MB levels measured at 12 hours after symptom onset. The admitting physician's 12-lead electrocardiographic (ECG) interpretation, 12-lead ECG algorithm (Marquette 12 SL V233) diagnosis, and BSM algorithm diagnosis were documented for each patient. AMI, defined by elevation of troponin I to >1 microg/L and/or creatine kinase-MB to >25U/L, occurred in 53 patients. The admitting physician diagnosed 24 patients with AMI (sensitivity 45%, specificity 94%), the 12-lead ECG algorithm diagnosed 17 patients with AMI (sensitivity 32%, specificity 98%), and the BSM algorithm diagnosed 34 patients with AMI (sensitivity 64%, specificity 94%). The BSM algorithm improved the diagnostic sensitivity by 2.0 (p <0.001) and 1.4 (p = 0.002) compared with the 12-lead ECG algorithm or the admitting physician, respectively. There was no significant difference in specificity. Thus, the BSM algorithm improves detection of AMI compared with the 12-lead ECG algorithm or physician's 12-lead ECG interpretation.

Aged↗
PubMed1998

Evaluation of subjective assessments and objective diagnostic tests for diagnosing tear-film disorders known to cause ocular irritation.

PURPOSE: To determine which subjective assessments and objective tests have clinical utility as diagnostic tools in ocular irritation associated with Sjögren's syndrome-related aqueous tear deficiency (ATD), non-Sjögren ATD, inflammatory meibomian gland disease (MGD) associated with rosacea, and atrophic MGD. METHODS: Forty adults with ocular irritation and 10 with normal ocular surfaces were enrolled in a nonrandomized, nonblinded clinical trial. Symptoms were evaluated. Tests included biomicroscopy; evaluation of tear-film integrity, production, and clearance; fluorescein and rose bengal staining; and serum autoantibody screening. RESULTS: Symptoms were similar among groups and most severe in the Sjögren's group. Fluorescein tear break-up time was significantly faster in the ATD and MGD groups than that in controls. Schirmer scores were significantly lower in the ATD group than those in MGD and control groups. Tear clearance was delayed in the ATD and atrophic MGD groups. Xeroscope grid distortion was noted only with ATD. The Sjögren's group had greater loss of naso-lacrimal reflex, slower fluorescein clearance, and greater ocular-surface fluorescein and rose bengal staining than did the others. More MGD subjects had meibomian gland orifice metaplasia and acinar dropout than did those with Sjögren-related ATD and controls. Schirmer scores correlated inversely with rose bengal staining, corneal fluorescein staining, and grid distortion. Rose bengal staining correlated with grid distortion and loss of nasal-lacrimal reflex, but not with MGD. CONCLUSION: Subjective assessments and objective diagnostic tests have clinical utility as diagnostic tools in tear-film disorders. ATD is correlated with ocular-surface disease. An algorithm summarizing the diagnostic utility of these tests is included.

Adolescent↗
PubMed2001

Improving the reliability of stroke subgroup classification using the Trial of ORG 10172 in Acute Stroke Treatment (TOAST) criteria.

BACKGROUND AND PURPOSE: We sought to improve the reliability of the Trial of ORG 10172 in Acute Stroke Treatment (TOAST) classification of stroke subtype for retrospective use in clinical, health services, and quality of care outcome studies. The TOAST investigators devised a series of 11 definitions to classify patients with ischemic stroke into 5 major etiologic/pathophysiological groupings. Interrater agreement was reported to be substantial in a series of patients who were independently assessed by pairs of physicians. However, the investigators cautioned that disagreements in subtype assignment remain despite the use of these explicit criteria and that trials should include measures to ensure the most uniform diagnosis possible. METHODS: In preparation for a study of outcomes and management practices for patients with ischemic stroke within Department of Veterans Affairs hospitals, 2 neurologists and 2 internists first retrospectively classified a series of 14 randomly selected stroke patients on the basis of the TOAST definitions to provide a baseline assessment of interrater agreement. A 2-phase process was then used to improve the reliability of subtype assignment. In the first phase, a computerized algorithm was developed to assign the TOAST diagnostic category. The reliability of the computerized algorithm was tested with a series of synthetic cases designed to provide data fitting each of the 11 definitions. In the second phase, critical disagreements in the data abstraction process were identified and remaining variability was reduced by the development of standardized procedures for retrieving relevant information from the medical record. RESULTS: The 4 physicians agreed in subtype diagnosis for only 2 of the 14 baseline cases (14%) using all 11 TOAST definitions and for 4 of the 14 cases (29%) when the classifications were collapsed into the 5 major etiologic/pathophysiological groupings (kappa=0.42; 95% CI, 0.32 to 0.53). There was 100% agreement between classifications generated by the computerized algorithm and the intended diagnostic groups for the 11 synthetic cases. The algorithm was then applied to the original 14 cases, and the diagnostic categorization was compared with each of the 4 physicians' baseline assignments. For the 5 collapsed subtypes, the algorithm-based and physician-assigned diagnoses disagreed for 29% to 50% of the cases, reflecting variation in the abstracted data and/or its interpretation. The use of an operations manual designed to guide data abstraction improved the reliability subtype assignment (kappa=0.54; 95% CI, 0.26 to 0.82). Critical disagreements in the abstracted data were identified, and the manual was revised accordingly. Reliability with the use of the 5 collapsed groupings then improved for both interrater (kappa=0.68; 95% CI, 0.44 to 0.91) and intrarater (kappa=0.74; 95% CI, 0.61 to 0.87) agreement. Examining each remaining disagreement revealed that half were due to ambiguities in the medical record and half were related to otherwise unexplained errors in data abstraction. CONCLUSIONS: Ischemic stroke subtype based on published TOAST classification criteria can be reliably assigned with the use of a computerized algorithm with data obtained through standardized medical record abstraction procedures. Some variability in stroke subtype classification will remain because of inconsistencies in the medical record and errors in data abstraction. This residual variability can be addressed by having 2 raters classify each case and then identifying and resolving the reason(s) for the disagreement.

Acute Disease↗
PubMed1987

Transferability of a computer system for medical history taking and decision support in dyspepsia. A comparison of indicants for peptic ulcer disease.

The transferability of a British data base for differential diagnosis of dyspepsia using data obtained by computer interrogation was tested in 467 Swedish patients. The diagnostic value for peptic ulcer disease of symptoms such as frequent night pain relieved by food or antacids, smoking, family history of ulcer, food relief pain, male sex, and episodic pain was shown to be reproducible. However, for a number of symptoms their value for the diagnosis of peptic ulcer disease could not be reproduced in Swedish patients. The combined value of indicants was tested using a computer based algorithm for calculating diagnostic probabilities. The performance of this algorithm was poor when British data were applied to Swedish patients but reclassification of the Swedish patients on their own data base showed promising results. Crean and colleagues in Glasgow have developed a computer system for automated interrogation of patients with dyspepsia. The system utilises a large number of questions to obtain information regarding a maximum of 160 diagnostic indicants. The symptoms elicited from a patient can be compared with those of a large number of previously examined patients and the probabilities of ten different diagnoses can be calculated. The calculation of diagnostic probabilities is based on scores reflecting the diagnostic value of different symptoms in different diseases. After careful translation of questions the system has been transferred for use in Sweden. The present report is based on data from patients seen during the first two years with the system at a Swedish hospital.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed2006

Increased diagnostic yield of small bowel tumors with capsule endoscopy.

BACKGROUND: It is believed that cancers of the small intestine represent <2% of all malignant tumors of the gastrointestinal tract, although the accuracy of this estimate is unknown, because the current methodologies for examining the small bowel have proved inadequate. Capsule endoscopy allows a more detailed inspection of the small intestine and may improve the ability to diagnose small bowel tumors. The objective of this study was to evaluate the effectiveness of capsule endoscopy in diagnosing small bowel tumors and to help establish the true incidence of tumors in obscure gastrointestinal bleeding. METHODS: A retrospective analysis of the charts of 562 patients who underwent capsule endoscopy from August 2001 to November 2003 for a variety of indications was performed. The indication for the procedure was bleeding (alone or in addition to another indication, such as abnormal imaging) in 443 patients. RESULTS: A diagnosis was made by capsule endoscopy in 277 patients (49.3%). Of 562 patients who were included in the study, 50 patients (8.9%) were diagnosed with small bowel tumors. The types of tumor diagnosed by capsule endoscopy included 8 adenocarcinomas (1.4%), 10 carcinoids (1.8%), 4 gastrointestinal stromal tumors (0.7%), 5 lymphomas (0.9%), 3 inflammatory polyps, 1 lymphangioma, 1 lymphangioectasia,1 hemangioma, 1 hamartoma, and 1 tubular adenoma. Of the tumors diagnosed, 48% were malignant. It was observed that 9 of 67 patients (13%) younger than age 50 years who underwent capsule endoscopy for obscure bleeding had small bowel tumors. The pathology results were not available for 10 patients. CONCLUSIONS: Capsule endoscopy diagnosed small bowel tumors in 8.9% of patients who underwent the procedure for a variety of reasons, establishing it as an effective diagnostic modality. This incidence of small bowel tumors suggests an important role for capsule endoscopy in the algorithm for the diagnostic work-up of patients with suspected small bowel lesions. Capsule endoscopy may lead to earlier detection and treatment of small bowel tumors and an improved prognosis for patients with these neoplasms.

Adolescent↗