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At least 883 records · Page 49Linked to original sources
PubMed2006

Stereotactic computed tomography-guided brain biopsy: diagnostic yield based on a series of 170 patients.

BACKGROUND: Stereotactic CT-guided biopsy is a valuable and safe procedure for diagnosing intracranial lesions. The objectives of this article are to analyze the diagnostic yield in a series of stereotactic CT-guided brain biopsies and to evaluate whether predictive factors may influence diagnostic yield. METHODS: The medical records of a series of patients who underwent stereotactic CT-guided brain biopsy from 1993 to 2005 in a neurosurgical center were reviewed. Clinical data were stored and analyzed with Microsoft Access (Microsoft Corp, Seattle, WA) and SPSS V11.0 software (SPSS, Inc, Chicago, IL). The following variables were analyzed: age, sex, anatomopathologic diagnosis, lesion topography and volume, postsurgical complications, and predictive factors that may affect diagnostic yield. RESULTS: One hundred seventy patients (102 males, 68 females; average age, 48.5 years) were analyzed. Stereotactic CT-guided biopsies allowed diagnosis in 157 cases (92%). The most frequent anatomopathologic diagnoses were high-grade glioma (n = 45), low-grade glioma (n = 31), nonspecific inflammatory lesions (n = 19), metastasis (n = 10), and lymphoma (n = 10). The most frequent topographies were frontal (n = 42), basal ganglia (n = 40), and parietal (n = 27) and front-parietal lobes (n = 9). Complications occurred in 5 patients (2.9%). Mortality rate was 1.2% (2 patients). Age had a positive impact, whereas female sex negatively affected diagnostic yield. All other predictive factors analyzed were not significant. CONCLUSION: Stereotactic CT-guided brain biopsies performed presented acceptable anatomopathologic diagnostic rate. Age had a positive impact, whereas female sex negatively affected diagnostic yield in this series.

Adult↗
PubMed1990

The effect of baseline electrocardiographic abnormalities on the diagnostic accuracy of exercise-induced ST segment changes.

Although exercise-induced ST segment depression is thought to be unreliable marker of myocardial ischemia in the presence of resting electrocardiographic changes, this conclusion is based on limited and disparate data from studies often lacking acceptable measures of ischemia. To determine the diagnostic accuracy of the ST segment response in a blinded prospective protocol, we compared ST deviation to thallium201 SPECT scintigraphy in 95 patients during exercise. Diagnostic accuracy was poor in the 95 patients with resting abnormalities: left bundle branch block (LBBB) = 70%, complete right bundle branch block (cRBBB) = 75%, incomplete right bundle branch block (incRBBB) = 79%, intraventricular conduction delay (IVCD) = 44%, left ventricular hypertrophy (LVH) = 59%, digitalis = 53%, compared with a diagnostic accuracy of 90% in 29 patients without resting changes. There were 20 false negative and 17 false positive ST segment responses. The extent and direction of resting ST deviation varied substantially and had no influence on diagnostic accuracy. The extent of change in ST deviation with exercise required for a positive response did not alter diagnostic accuracy: -1.0 mm = 61%, -1.5 mm = 63%, and -2.0 = 61%. While the location of regional ischemia did not influence the accuracy of ST segment analysis, a QRS duration less than 120 msec did improve diagnostic accuracy. Our data confirm that ST segment analysis with exercise testing is not reliable in patients with resting electrocardiographic abnormalities and demonstrates that accuracy is not improved by adjusting for either resting or exercise-induced ST segment changes or for location of the ischemic region.

Aged↗
PubMed1997

Sex and diagnostic evaluation of possible coronary artery disease after exercise treadmill testing at one academic teaching center.

Controversy exists as to whether a sex bias exists that affects the diagnostic approach to suspected coronary artery disease: previous studies have used coronary angiography, but not other noninvasive testing, as a primary end point. This investigation examined posttest sex differences in diagnostic evaluation after exercise treadmill testing according to a broader end point than just coronary angiography alone. The design was a cohort analytic study with a 90-day follow-up. The study was done at the Cleveland Clinic Foundation, an academic group practice. Patients included consecutive adults (1023 men and 579 women) with chest pain but no documented coronary disease who were referred for symptom-limited exercise treadmill testing without adjunctive imaging; none had undergone prior invasive cardiac procedures. Main outcome measures included (1) performance of any subsequent diagnostic study (invasive or noninvasive) and (2) performance of coronary angiography as the next diagnostic study. During follow-up, 89 (8.7%) men and 48 (8.3%) women underwent a second diagnostic study (odds ratio 0.95; 95% confidence interval 0.66 to 1.37; p > 0.8), whereas 64 (6.3%) men and 21 (3.6%) women went straight to coronary angiography (odds ratio 0.56; 95% confidence interval 0.34 to 0.93; p = 0.02). In multivariable logistic regression analyses, which considered baseline clinical characteristics, the ST-segment response, and other prognostically important exercise responses, women tended to be less likely than men to be referred to any second test (adjusted odds ratio 0.70; 95% confidence interval 0.42 to 1.19; p > 0.1) but were markedly and significantly less likely to be referred straight to coronary angiography (adjusted odds ratio 0.33; 95% confidence interval 0.17 to 0.65). After exercise treadmill testing, women were only slightly less likely than men to be referred for subsequent diagnostic testing; they were, however, much less likely to be referred straight to coronary angiography as opposed to another noninvasive study.

Academic Medical Centers↗
PubMed2001

A new coronary artery disease index of treadmill exercise electrocardiograms based on the step-up diagnostic method.

Treadmill exercise electrocardiography (ECG) is one of the most common noninvasive methods for detecting ischemic heart disease. However, this method has problems due to false-positive and false-negative results in a significant number of patients. The aim of this study was to determine whether the diagnostic accuracy of treadmill exercise ECG for detecting significant coronary stenosis can be improved by employing a step-up diagnostic method using multiple diagnostic indicators. We studied 273 consecutive patients (mean age, 56 +/- 9 years; 190 men and 83 women) without a history of myocardial infarction who underwent treadmill exercise ECG and coronary angiography for ischemic chest pain. Of these, 146 patients had no significant coronary stenosis, 61 had single-vessel disease, 56 had multivessel disease, and 10 patients had left main truncus disease. A multivariate logistic regression analysis was used to select 3 treadmill exercise electrocardiographic parameters that were independent predictors of the presence or absence of significant coronary stenosis: exercise-induced maximum ST-segment depression, QT dispersion immediately after exercise, and Athens QRS score. Significant coronary stenosis was diagnosed with a sensitivity of 84% and a specificity of 90% when a step-up diagnostic method using these 3 indicators was employed. These results were better than those obtained for each indicator alone (exercise-induced maximum ST-segment depression: sensitivity, 66%, and specificity, 73%; QT dispersion immediately after exercise [> or =60 ms positive]: sensitivity, 76%, and specificity, 86%; and Athens QRS score [< or =5 mm positive]: sensitivity, 72%, and specificity, 72%). We conclude that this step-up diagnostic method, using multiple diagnostic indicators, is a clinically useful predictor of the presence or absence of significant coronary stenosis.

Aged↗
PubMed1986

Indications for and diagnostic efficacy of open-lung biopsy in the patient with acquired immunodeficiency syndrome (AIDS).

Pulmonary infiltrates in the patient with acquired immunodeficiency syndrome (AIDS) may be associated with a spectrum of unusual neoplastic and infectious process. Transbronchial biopsy frequently reveals the cause of these infiltrates; however, when transbronchial biopsy is nondiagnostic or contraindicated, or if the patient fails to improve after a diagnostic transbronchial biopsy, further investigation is warranted to direct appropriate therapy. Efficacy of 23 open-lung biopsies in 19 AIDS patients with pulmonary infiltrates was evaluated to define the indications for and the diagnostic yield of open-lung biopsy. Pulmonary infiltrates were recognized for a mean duration (+/- standard error) of 16 +/- 2 days before open-lung biopsy and were associated with fever and cough. These patients did not have prior transbronchial biopsy, and open-lung biopsy was diagnostic in all of these. Prior transbronchial biopsy performed in the remaining 16 patients was nondiagnostic in 10. Open-lung biopsy was diagnostic in 70% of these patients (Pneumocystis carinii pneumonia, 2 patients; Kaposi's sarcoma, 3 patients; Kaposi's sarcoma and Legionella pneumophila, 1 patient; cytomegalovirus, 1 patient). The other 6 patients having a previous diagnostic transbronchial biopsy failed to improve with therapy, and open-lung biopsy resulted in a therapeutic change in 67% of these patients. Two deaths were attributable to open-lung biopsy in patients with postoperative thrombocytopenic hemorrhage. Open-lung biopsy should be performed in AIDS patients when transbronchial biopsy is nondiagnostic or contraindicated, or in patients who fail to improve with appropriate therapy after diagnostic transbronchial biopsy, especially in patients with Kaposi's sarcoma.(ABSTRACT TRUNCATED AT 250 WORDS)

Acquired Immunodeficiency Syndrome↗
PubMed1988

Gamete intrafallopian tube transfer (GIFT): making laparoscopy more than "diagnostic".

Diagnostic laparoscopy is commonly performed on patients as part of a complete infertility investigation. Recently published protocols have investigated the efficacy of using empiric ovulation induction, intrauterine insemination, or both before beginning in vitro fertilization. Because many patients enrolled in these protocols will be exposed to both ovulation induction and diagnostic laparoscopy, the authors reasoned that it would be more effective to begin ovulation induction at the time of the proposed diagnostic laparoscopy in order to allow gamete intrafallopian tube transfer (GIFT) at the same time. Twenty-five nulliparous patients underwent diagnostic GIFT. There were eight continuing pregnancies in this group (32%). Diagnostic GIFT is a more effective use of the opportunity provided by laparoscopy than diagnostic laparoscopy alone.

Adult↗
PubMedDate not supplied

Bacteremia following diagnostic and therapeutic ERCP.

The occurrence of bacteremia in association with diagnostic or therapeutic ERCP was studied in 180 patients undergoing a total of 194 examinations. Nineteen (15%) of 126 diagnostic procedures and 18 (27%) of 68 therapeutic procedures were associated with bacteremia (p less than 0.1). Nine patients had polymicrobial bacteremia and a total of 16 species were detected. Different streptococci, mainly alpha-hemolytic, were the most common bacteria which were identified in 38% of the bacteremic patients. There were no significant differences with regard to the occurrence of fever, pancreatitis, or septic complications between the diagnostic and therapeutic groups of patients. Neither did the complication rate in patients with bacteremia differ from that in patients without bacteremia, whether the procedure was diagnostic or therapeutic. Complication rates did not differ between patients with and patients without pancreaticobiliary obstruction. However, the majority of patients with biliary stasis had drainage with relief of the obstruction at the time of the diagnostic ERCP. We conclude that general routine antibiotic prophylaxis is not indicated in patients undergoing diagnostic or therapeutic ERCP. The question whether such prophylaxis should be given with certain diagnoses or treatments, or in patients with valvular heart disease, remains to be answered in controlled randomized studies.

Aged↗
PubMed2006

New insights into the diagnostic accuracy of complexed and total prostate specific antigen using discordance analysis characteristics.

PURPOSE: Comparison of diagnostic performances of total and complexed prostate specific antigen (tPSA, cPSA) using ROC curve analysis resulted in controversial interpretations. To overcome the biases due to analysis of subgroups selected by concentration ranges of only 1 marker the novel approach named discordance analysis characteristics is presented. MATERIALS AND METHODS: DAC method includes only patients who are discordantly categorized by the tests under investigation using cutoffs with identical sensitivity. Within those patients parameters describing diagnostic accuracy are calculated. The systematic nature of the results is confirmed by varying the cutoffs. DAC method is demonstrated considering the example of cPSA and tPSA data from 2 prostate cancer studies with a total of 1,624 patients (study A and B, of 283 and 565 with as well as 417 and 359 men without prostate cancer, respectively). PSA concentrations were measured using the Bayer assays. RESULTS: The DAC method proved that cPSA outperformed tPSA regarding the criteria diagnostic specificity and positive predictive value. Among discordantly tested patients cPSA detected patients with an about 2-fold higher risk to have prostate cancer and with a 3.6 to 5.5-fold better specificity than tPSA. Using cPSA instead of tPSA more than 10% of unnecessary biopsies could be avoided in the tPSA range of 3 to 5 ng/ml. CONCLUSIONS: The superior diagnostic performance of cPSA in comparison with tPSA warrants the recommendation to use cPSA as initial test in prostate cancer diagnostics. The DAC method is generally recommended to replace comparative ROC analyses of subgroups to evaluate the diagnostic usefulness of markers.

Humans↗
PubMed2004

Risk of cancer from diagnostic X-rays: estimates for the UK and 14 other countries.

BACKGROUND: Diagnostic X-rays are the largest man-made source of radiation exposure to the general population, contributing about 14% of the total annual exposure worldwide from all sources. Although diagnostic X-rays provide great benefits, that their use involves some small risk of developing cancer is generally accepted. Our aim was to estimate the extent of this risk on the basis of the annual number of diagnostic X-rays undertaken in the UK and in 14 other developed countries. METHODS: We combined data on the frequency of diagnostic X-ray use, estimated radiation doses from X-rays to individual body organs, and risk models, based mainly on the Japanese atomic bomb survivors, with population-based cancer incidence rates and mortality rates for all causes of death, using life table methods. FINDINGS: Our results indicate that in the UK about 0.6% of the cumulative risk of cancer to age 75 years could be attributable to diagnostic X-rays. This percentage is equivalent to about 700 cases of cancer per year. In 13 other developed countries, estimates of the attributable risk ranged from 0.6% to 1.8%, whereas in Japan, which had the highest estimated annual exposure frequency in the world, it was more than 3%. INTERPRETATION: We provide detailed estimates of the cancer risk from diagnostic X-rays. The calculations involved a number of assumptions and so are inevitably subject to considerable uncertainty. The possibility that we have overestimated the risks cannot be ruled out, but that we have underestimated them substantially seems unlikely.

Adolescent↗
PubMed2006

Identification of diagnostic markers for tuberculosis by proteomic fingerprinting of serum.

BACKGROUND: We investigated the potential of proteomic fingerprinting with mass spectrometric serum profiling, coupled with pattern recognition methods, to identify biomarkers that could improve diagnosis of tuberculosis. METHODS: We obtained serum proteomic profiles from patients with active tuberculosis and controls by surface-enhanced laser desorption ionisation time of flight mass spectrometry. A supervised machine-learning approach based on the support vector machine (SVM) was used to obtain a classifier that distinguished between the groups in two independent test sets. We used k-fold cross validation and random sampling of the SVM classifier to assess the classifier further. Relevant mass peaks were selected by correlational analysis and assessed with SVM. We tested the diagnostic potential of candidate biomarkers, identified by peptide mass fingerprinting, by conventional immunoassays and SVM classifiers trained on these data. FINDINGS: Our SVM classifier discriminated the proteomic profile of patients with active tuberculosis from that of controls with overlapping clinical features. Diagnostic accuracy was 94% (sensitivity 93.5%, specificity 94.9%) for patients with tuberculosis and was unaffected by HIV status. A classifier trained on the 20 most informative peaks achieved diagnostic accuracy of 90%. From these peaks, two peptides (serum amyloid A protein and transthyretin) were identified and quantitated by immunoassay. Because these peptides reflect inflammatory states, we also quantitated neopterin and C reactive protein. Application of an SVM classifier using combinations of these values gave diagnostic accuracies of up to 84% for tuberculosis. Validation on a second, prospectively collected testing set gave similar accuracies using the whole proteomic signature and the 20 selected peaks. Using combinations of the four biomarkers, we achieved diagnostic accuracies of up to 78%. INTERPRETATION: The potential biomarkers for tuberculosis that we identified through proteomic fingerprinting and pattern recognition have a plausible biological connection with the disease and could be used to develop new diagnostic tests.

Adolescent↗
PubMed1999

Silent embolism in diagnostic cerebral angiography and neurointerventional procedures: a prospective study.

BACKGROUND: Cerebral angiography is associated with a small but definite risk of neurological complications with an unknown incidence of clinically silent embolism. We assessed the neurological complication rate compared with the frequency of silent embolism after angiography METHODS: We used diffusion-weighted magnetic resonance imaging (MRI) before and after angiography to assess embolic events. 100 consecutive angiographies (66 diagnostic and 34 interventional procedures) were done on 91 patients. Patients underwent neurological assessment before, immediately after, and 1 day after angiography. FINDINGS: Before angiography, no abnormalities were seen on diffusion-weighted MRI. Diffusion-weighted MRI showed 42 bright lesions in 23 patients after 23 procedures (17 diagnostic, six interventional) in a pattern consistent with embolic events. There was no new neurological deficit after any angiographic procedure. After diagnostic angiography in patients with a history of vasculopathy, the frequency of lesions was significantly higher than in patients without vascular risk factors (12 [44%] of 27 vs five [13%] of 39 patients, p=0.03). In diagnostic angiography, the appearance of lesions was significantly correlated with whether vessels were difficult to probe (p=0.01), amount of contrast medium needed (p<0.01), fluoroscopy time (p<0.01), and use of additional catheters (p=0.02). INTERPRETATION: After diagnostic and interventional cerebral angiography, embolic events are more frequent than the apparent neurological complication rate. In diagnostic procedures, the incidence of embolism is closely related to a vascular risk profile.

Adolescent↗
PubMed1998

Epidemiologic and phenomenological aspects of post-traumatic stress disorder: DSM-III-R diagnosis and diagnostic criteria not validated.

The aim of this cohort study was: (i) to validate the diagnostic criteria for post-traumatic stress disorder (PTSD) of the DSM-III-R; and (ii) to examine the incidence rate of PTSD in a study population exposed to two different traumatic events, i.e. a fire in a hotel ball-room and a multiple collision car-crash on a Belgian highway. One hundred and eighty-five victims (130 fire and 55 car accident victims) were assessed between 7 and 9 months after the traumatic event using the Composite International Diagnostic Interview (CIDI), PTSD Module, a fully structured diagnostic interview for the assessment of PTSD according to DSM-III-R criteria. Twenty-three percent of the study population met DSM-III-R criteria for PTSD. By means of unsupervised and supervised multivariate statistical analyses we were unable to validate the three-factorial structure, i.e. criteria B, C and D, of the DSM-III-R PTSD diagnosis. The latter relies heavily on the C diagnostic criteria, which appear to be too restrictive. Women were more likely to develop symptoms of reexperience (B) and arousal (D) than men. There was a significantly higher incidence of criteria B, C and D, but not of PTSD, in fire than in car-accident victims. Between 42 and 57% of the victims developed the first PTSD symptoms on the day of the trauma; within the next week these incidence rates increased to 77.1, 57.8 and 73.5% for criteria B, C and D, respectively. In conclusion, this study was unable to demonstrate the validity of the diagnostic criteria for PTSD according to DSM-III-R. The present cohort study has defined a number of factors that may predict new occurrences of PTSD symptoms after a traumatic event, i.e. gender, type of trauma and time delay between the trauma and the assessment of the diagnostic criteria.

Accidents, Traffic↗
PubMed1997

Epiluminescence microscopy of small pigmented skin lesions: short-term formal training improves the diagnostic performance of dermatologists.

BACKGROUND: Epiluminescence microscopy (ELM) makes subsurface structures of the skin accessible for in vivo examination and provides additional criteria for the clinical diagnosis of pigmented skin lesions (PSLs). We demonstrated that ELM increases diagnostic sensitivity in dermatologists formally trained in the use of this technique but decreases diagnostic ability in dermatologists not formally trained in its application. OBJECTIVE: Our purpose was to determine the effects of short formal ELM training on the diagnostic performance of 11 previously untrained dermatologists. METHODS: One hundred image-pairs of randomly selected histologically proven PSLs, photographed with (ELM) and without oil immersion (surface microscopy), were presented by slide projection to the testees. To evaluate the effects on diagnostic performance before and after short-term training, we used the receiver-operator characteristics technique. RESULTS: Without training the use of ELM did not enhance diagnostic accuracy, but rather decreased it in 8 of 11 testees. In contrast, after 9 hours of formal training in ELM the diagnostic performance of the testees was significantly enhanced with an average gain of 8.4%. CONCLUSION: Our data confirm that formal training is required for the useful application of the ELM technique.

Austria↗
PubMed2003

[Transbronchial needle aspiration in bronchogenic carcinoma with visible lesions: diagnostic yield and cost].

BACKGROUND: Transbronchial needle aspiration (TBNA) is a bronchoscopic technique whose usefulness in diagnosing endobronchial lesions has not yet been clearly established. OBJECTIVE: We aimed to determine whether the diagnostic yield of fiberoptic bronchoscopy could be increased, without a negative impact on diagnostic costs, if TBNA were used in combination with conventional diagnostic techniques (bronchial washings and bronchial brushings and forceps biopsy). PATIENTS AND METHODS: The cases of 130 patients diagnosed with bronchogenic carcinoma with endoscopically visible lesions were analyzed retrospectively. All had undergone conventional diagnostic procedures; TBNA was also performed if the bronchoscopist considered it was indicated. The final cost was calculated in euros for each diagnosis as the sum of the cost of the procedures needed to reach the diagnosis, including both endoscopic procedures and others (transthoracic needle aspiration, lymph node biopsy). Diagnostic yield and costs in cases diagnosed using only conventional techniques were compared to the yield and costs in cases in which both conventional techniques and TBNA were used. RESULTS: TBNA was performed in 49 patients and provided the diagnosis in 85.7%. Conventional techniques led to cytological and histological diagnosis in 80.2% of the cases, and the combination of conventional techniques and TBNA gave a diagnosis in 89.7% (P=.01). Significant differences were observed in extrinsic compression (conventional 37.5%; conventional+TBNA 100%; P=.01), submucosal infiltration (conventional 54.6%; conventional+TBNA 85%; P=.03), and exophytic mass with necrosis (conventional 80%; conventional+TBNA 100%; P=.01). The mean (SD) cost of diagnosis was euros 381.60 (euros 156.53) using conventional techniques and euros 413.25 (euros 112.91) for conventional techniques in combination with TBNA. By adding TBNA, costs decreased for diagnoses of submucosal infiltration, exophytic mass with necrosis and extrinsic compression, although the saving was significant only for extrinsic compression. CONCLUSION: The diagnostic yield of TBNA is high for endoscopically visible bronchial anomalies suggesting neoplasm, particularly when the lesion is due to extrinsic compression, submucosal infiltration, or exophytic mass with necrosis.

Biopsy, Needle↗
PubMed1998

[Factors related to diagnostic yield and complications of transbronchial biopsy].

To study the diagnostic yield of transbronchial biopsy (TBB) in lung diseases of different ethiology, as well as to examine several factors implicated in diagnostic yield and complications of TBB. Retrospective study of a series of 172 patients (98 women and 74 men) undergoing TBB. Clinical variables, x-ray and CT patterns and technical factors related to TBB were analyzed in relation to diagnostic yield and definitive diagnosis. We recorded the main complications and studied the possible mechanisms implicated in their appearance. The results of TBB were classified as follows: 1) diagnostic TBB (42.8%); 2) nonspecific TBB (21.1%); absence of parenchyma (NP) (9.7%); 4) normal parenchyma (23.4%); 5) incorrect diagnosis (2.9%). Overall yield was 43.6% but rose to 52% when NP and no infiltrative pneumopathies were excluded. The main findings were infections (23.4%), neoplasms (19.4%), sarcoidosis (14.2%), idiopathic pulmonary fibrosis (IPF) (17.7%); and other (23.4%). Significant differences in diagnosis were found for age, sex, time of evolution prior to TBB, and x-ray and CT patterns. Complications and pneumothorax appeared more frequently in IPF, neoplasms and infections, although the differences were non significant. Diagnostic value depended mainly on type of disease and ranged from 60% for sarcoidosis to 24% for IPF (p < 0.05), with no differences related to age, sex, presence of immunosuppression, number of TBB or tolerance to exploration. Yield was higher, however, for patients with no loss of radiographic pulmonary volume (56.3% versus 37.5%) and with absence of a CT reticular pattern (44.7% versus 27.3%). Type of opacites also influenced yield (53.4% for ground glass versus 26.7% for reticular patterns), as did distribution of lesions (8.4% for peripheral patterns versus 48.3% for diffuse patterns and 50% for peribronchio-vascular patterns). The site of TBB was the only factor showing clearly significant differences in yield (100% in mild lobe versus 29.5% in upper lobes). Tolerance was poorer in older patients (63.5 +/- 10 versus 52.2 +/- 17 years) and with greater function abnormalities (%FEV1: 48.2 +/- 16.8 versus 70.2 +/- 17.1). Poor tolerance of exploration was associated with the appearance of complications (16.6% vs 6.3) and pneumothorax (25% versus 6.8%). The diagnostic yield of TBB was mainly influenced by the type of disease studied. The various imaging techniques were fundamental for establishing preliminary diagnoses and degree of evolution of a specific cases. In our series, tolerance of the technique was a reliable predictor of complications and the presence of post-biops pneumothorax.

Adult↗
PubMed2003

Evaluation of toe pressure and transcutaneous oxygen measurements in management of chronic critical leg ischemia: a diagnostic randomized clinical trial.

OBJECTIVE: The definition of critical limb ischemia (CLI) requiring vascular intervention is still under debate. The clinical eye of the physician and ankle blood pressure measurements used so far may fall short in appreciation of the severity of disease, which makes decision-making for a vascular intervention subjective. In previous studies two simple functional tests, ie, transcutaneous oxygen pressure (tcPo(2)) and toe blood pressure (TP) measurements, provided reliable information about the need for vascular intervention. Therefore we evaluated the diagnostic value of tcPo(2) and TP in management of clinically suspected critical leg ischemia. Study design This was a diagnostic randomized controlled clinical trial. Subjects were ambulatory and hospitalized patients in a referral university hospital. METHODS: Ninety-six patients (128 legs) with clinically suspected critical limb ischemia were referred to the vascular laboratory for routine investigation. Two diagnostic management strategies were compared: conventional strategy, ie, clinical judgment and ankle pressure determined the diagnostic and therapeutic approach, and a new strategy in which tcPo(2) and TP determined the diagnostic and therapeutic approach. Main outcome measures included clinical outcome, defined as pain relief, wound healing, and limb survival. RESULTS: At 18-month follow-up, 26 of 62 legs treated with the conventional approach and 28 of 66 legs treated with the new approach were treated conservatively. The new method did not score significantly different from the conventional method insofar as clinical outcome: pain score, 50 versus 48; number of amputations, 8 versus 10; and number of deaths, 11 versus 8 deaths, respectively. CONCLUSION: Two simple objective diagnostic tests, TP and tcPo(2), did not improve clinical outcome when incorporated into routine management of suspected critical limb ischemia. Nevertheless, these techniques might still be helpful for physicians less experienced with treating critical limb ischemia and who are in doubt regarding the need for vascular intervention.

Aged↗
PubMed2003

The diagnostic odds ratio: a single indicator of test performance.

Diagnostic testing can be used to discriminate subjects with a target disorder from subjects without it. Several indicators of diagnostic performance have been proposed, such as sensitivity and specificity. Using paired indicators can be a disadvantage in comparing the performance of competing tests, especially if one test does not outperform the other on both indicators. Here we propose the use of the odds ratio as a single indicator of diagnostic performance. The diagnostic odds ratio is closely linked to existing indicators, it facilitates formal meta-analysis of studies on diagnostic test performance, and it is derived from logistic models, which allow for the inclusion of additional variables to correct for heterogeneity. A disadvantage is the impossibility of weighing the true positive and false positive rate separately. In this article the application of the diagnostic odds ratio in test evaluation is illustrated.

Diagnosis↗
PubMed2000

Improving diagnostic accuracy using a hierarchical neural network to model decision subtasks.

A number of quantitative models including linear discriminant analysis, logistic regression, k nearest neighbor, kernel density, recursive partitioning, and neural networks are being used in medical diagnostic support systems to assist human decision-makers in disease diagnosis. This research investigates the decision accuracy of neural network models for the differential diagnosis of six erythematous-squamous diseases. Conditions where a hierarchical neural network model can increase diagnostic accuracy by partitioning the decision domain into subtasks that are easier to learn are specifically addressed. Self-organizing maps (SOM) are used to portray the 34 feature variables in a two dimensional plot that maintains topological ordering. The SOM identifies five inconsistent cases that are likely sources of error for the quantitative decision models; the lower bound for the diagnostic decision error based on five errors is 0.0140. The traditional application of the quantitative models cited above results in diagnostic error levels substantially greater than this target level. A two-stage hierarchical neural network is designed by combining a multilayer perceptron first stage and a mixture-of-experts second stage. The second stage mixture-of-experts neural network learns a subtask of the diagnostic decision, the discrimination between seborrheic dermatitis and pityriasis rosea. The diagnostic accuracy of the two stage neural network approaches the target performance established from the SOM with an error rate of 0.0159.

Chronic Disease↗