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PubMed1999

Differentiating between septic arthritis and transient synovitis of the hip in children: an evidence-based clinical prediction algorithm.

BACKGROUND: A child who has an acutely irritable hip can pose a diagnostic challenge. The purposes of this study were to determine the diagnostic value of presenting variables for differentiating between septic arthritis and transient synovitis of the hip in children and to develop an evidence-based clinical prediction algorithm for this differentiation. METHODS: We retrospectively reviewed the cases of children who were evaluated at a major tertiary-care children's hospital between 1979 and 1996 because of an acutely irritable hip. Diagnoses of true septic arthritis, presumed septic arthritis, and transient synovitis were explicitly defined on the basis of the white blood-cell count in the joint fluid, the results of cultures of joint fluid and blood, and the clinical course. Univariate analysis and multiple logistic regression analysis were used to compare groups. A probability algorithm for differentiation between septic arthritis and transient synovitis on the basis of independent multivariate predictors was constructed and tested. RESULTS: Patients who had septic arthritis differed significantly (p < 0.05) from those who had transient synovitis with regard to the erythrocyte sedimentation rate, serum white blood-cell count and differential, weight-bearing status, history of fever, temperature, evidence of effusion on radiographs, history of chills, history of recent antibiotic use, hematocrit, and gender. Patients who had true septic arthritis differed significantly (p < 0.05) from those who had presumed septic arthritis with regard to history of recent antibiotic use, history of chills, temperature, erythrocyte sedimentation rate, history of fever, gender, and serum white blood-cell differential. Four independent multivariate clinical predictors were identified to differentiate between septic arthritis and transient synovitis: history of fever, non-weight-bearing, erythrocyte sedimentation rate of at least forty millimeters per hour, and serum white blood-cell count of more than 12,000 cells per cubic millimeter (12.0 x 10(9) cells per liter). The predicted probability of septic arthritis was determined for all sixteen combinations of these four predictors and is summarized as less than 0.2 percent for zero predictors, 3.0 percent for one predictor, 40.0 percent for two predictors, 93.1 percent for three predictors, and 99.6 percent for four predictors. The chi-square test for trend and the area under the receiver operating characteristic curve indicated excellent diagnostic performance of this group of multivariate predictors in identifying septic arthritis. CONCLUSIONS: Although several variables differed significantly between the group that had septic arthritis and the group that had transient synovitis, substantial overlap in the intermediate ranges made differentiation difficult on the basis of individual variables alone. However, by combining variables, we were able to construct a set of independent multivariate predictors that, together, had excellent diagnostic performance in differentiating between septic arthritis and transient synovitis of the hip in children.

Acute Disease↗

PubMed2000

Validation and comparison of three brief depression scales in an elderly Chinese population.

The study aimed to establish the diagnostic accuracy of the Geriatric Depression Scale (GDS), the Even Briefer Assessment Scale for Depression (EBAS DEP), and the single question test for depression in our elderly Chinese population, and to determine if any one instrument was to be preferred. Ninety-eight community-living, socially active and non-depressed elderly and 75 patients diagnosed with depression were administered the three depression scales. Receiver operating characteristics (ROC) were employed to determine the optimal cut-off scores for the GDS and EBAS DEP, and the diagnostic performance of all three instruments were then compared. ROC analysis indicated an optimal cut-off score of 4 and above for the 15-item GDS, with a sensitivity of 84.0% and a specificity of 85.7%, while the EBAS DEP had 77.3% sensitivity and 89.8% specificity at the optimal cut-off score of 3 and above. The sensitivity and specificity of the single question were 64.0% and 94.9%, respectively. The non-parametric test of the areas-under-the-curve showed no significant difference between the diagnostic performances of the GDS and the EBAS DEP; visually, however, the ROC plot of the GDS was superior. The GDS, the EBAS DEP, and the single question were all valid screening tools for depression in the elderly Chinese population. For busy physicians, there is rationale to first use the single-question test, supplemented where necessary with either the GDS or the EBAS DEP, as an efficient diagnostic strategy for identifying depression amongst older Chinese patients.

Aged↗

PubMed2006

Performance and diagnostic evaluation of ozone predictions by the Eta-Community Multiscale Air Quality Forecast System during the 2002 New England Air Quality Study.

A real-time air quality forecasting system (Eta-Community Multiscale Air Quality [CMAQ] model suite) has been developed by linking the National Centers for Environmental Estimation Eta model to the U.S. Environmental Protection Agency (EPA) CMAQ model. This work presents results from the application of the Eta-CMAQ modeling system for forecasting ozone (O3) over the Northeastern United States during the 2002 New England Air Quality Study (NEAQS). Spatial and temporal performance of the Eta-CMAQ model for O3 was evaluated by comparison with observations from the EPA Air Quality System (AQS) network. This study also examines the ability of the model to simulate the processes governing the distributions of tropospheric O3 on the basis of the intensive datasets obtained at the four Atmospheric Investigation, Regional Modeling, Analysis, and Estimation (AIRMAP) and Harvard Forest (HF) surface sites. The episode analysis reveals that the model captured the buildup of O3 concentrations over the northeastern domain from August 11 and reproduced the spatial distributions of observed O3 very well for the daytime (8:00 p.m.) of both August 8 and 12 with most of normalized mean bias (NMB) within +/- 20%. The model reproduced 53.3% of the observed hourly O3 within a factor of 1.5 with NMB of 29.7% and normalized mean error of 46.9% at the 342 AQS sites. The comparison of modeled and observed lidar O3 vertical profiles shows that whereas the model reproduced the observed vertical structure, it tended to overestimate at higher altitude. The model reproduced 64-77% of observed NO2 photolysis rate values within a factor of 1.5 at the AIRMAP sites. At the HF site, comparison of modeled and observed O3/nitrogen oxide (NOx) ratios suggests that the site is mainly under strongly NOx-sensitive conditions (>53%). It was found that the modeled lower limits of the O3 production efficiency values (inferred from O3-CO correlation) are close to the observations.

Air Pollutants↗

PubMed2004

Clinical feasibility of two-step streptavidin/111In-biotin scintigraphy in patients with suspected vertebral osteomyelitis.

PURPOSE: Streptavidin accumulates at sites of inflammation and infection as a result of increased capillary permeability. In addition to being utilised by bacteria for their own growth, biotin forms a stable, high-affinity non-covalent complex with avidin. The objective of this investigation was to determine the diagnostic performance of two-step streptavidin/111In-biotin imaging for evaluating patients with suspected vertebral osteomyelitis. METHODS: We evaluated 55 consecutive patients with suspected vertebral osteomyelitis (34 women and 21 men aged 27-86 years), within 2 weeks after the onset of clinical symptoms. Thirty-two of the patients underwent magnetic resonance imaging (MRI) and 24, computed tomography (CT). DTPA-conjugated biotin was radiolabelled by incubating 500 microg of DTPA-biotin with 111 MBq of 111In-chloride. Two-step scintigraphy was performed by first infusing 3 mg streptavidin intravenously, followed 4 h later by 111In-biotin. Imaging was begun 60 min later. RESULTS: Streptavidin/111In-biotin scintigraphy was positive in 32/34 patients with spinal infection (94.12% sensitivity). The study was negative in 19/21 patients without infection (95.24% specificity). The corresponding results for MRI and CT were 54.17% and 35.29% (sensitivity), and 75% and 57.14% (specificity), respectively. All statistical parameters of diagnostic performance (Youden's J index, kappa measure of agreement with correct classification, accuracy, sensitivity, specificity, positive likelihood and negative likelihood) were clearly better for streptavidin/111In-biotin scintigraphy than for either MRI or CT. CONCLUSION: Streptavidin/111In-biotin scintigraphy is highly sensitive and specific for detecting vertebral osteomyelitis in the first 2 weeks after the onset of clinical symptoms, and is potentially very useful for guiding clinical decisions on instituting appropriate therapy.

Adult↗

PubMed1999

Validation of the indirect MAP1-B enzyme-linked immunosorbent assay for diagnosis of experimental Cowdria ruminantium infection in small ruminants.

The major antigenic protein 1 fragment B (MAP1-B) enzyme-linked immunosorbent assay (ELISA) for the diagnosis of Cowdria ruminantium infections was validated to determine cutoff values and evaluate its diagnostic performance with sheep and goat sera. Cowdria-infected populations consisted of 48 sheep and 44 goats, while the noninfected populations consisted of 64 sheep and 107 goats. Cutoff values were determined by two-graph receiver-operating characteristic (TG-ROC) curves. The cutoff value was set at 31 and 26.6% of the positive control reference samples for sheep and goat sera, respectively. The test's diagnostic performance was evaluated with measurements of the area under the concentration-time curve (AUC) of the ROC curves and by the valid range proportion (VRP). The AUCs were 0.978 for sheep sera and 0.989 for goat sera. The VRP for both sheep and goat sera was approximately 1.0. The intermediate range (IR), which defines results that are neither positive nor negative, was 0 for goat sera and 2.81 for sheep sera. In an ideal test, the AUC and VRP would be 1.0 and the IR would be 0. In this study these parameters were close to those of an ideal test. It is concluded that the MAP1-B ELISA is a useful test for the diagnosis of C. ruminantium infection in small ruminants.

Animals↗

PubMedDate not supplied

Tumor markers in breast cancer monitoring should be scheduled according to initial stage and follow-up time: a prospective study on 859 patients.

PURPOSE: The purpose of this study was to identify and standardize optimal decision criteria for maximizing the effectiveness of tumor markers in clinical use during the follow-up of patients operated on for breast cancer. MATERIALS AND METHODS: The study was prospectively performed on 859 patients enrolled in 10 institutions. A total of 13,337 determinations of CEA and 14,330 determinations of CA15.3 were available. The median number of samples per patient was 16 for CEA and 17 for CA15.3. The median follow-up was 7 years. Receiver-operating characteristic analysis was used to evaluate the ability of CEA and CA15.3 to discriminate relapses from patients who had no evidence of disease. The diagnostic performances of the two markers were evaluated using decision criteria based on both dichotomic cut-off points and dynamic variations among serial samples. RESULTS: We selected decision levels corresponding to preset levels of 90% and 99% specificity. Patients with CEA and/or CA15.3 levels above the cut-off values were considered positive only if a 1.5-fold increase occurred among the last sample and the mean of the first three samples. According to the different cut-offs used, specificity ranged from 94% to 99% and sensitivity from 48% to 63%. We calculated predictive values using the prevalence expected with reference to the stage of primary tumor and the length of follow-up. Positive predictive values ranged from 1.6% to 93.7%, and negative predictive values from 88.9% to 100%, according to the clinical scenarios and the decision criteria used. The choice of the decision criteria significantly affected positive predictive values within each patient subset. Differences related to time from surgery were still remarkable for every decision criteria (i.e., positive predictive values ranged from 36.6% to 2.8% in node-negative patients according to the year of observation, although the same cut-off point was used). DISCUSSION: The results of the present prospective study show that different decision criteria may provide different diagnostic performances for the same tumor marker and in the same patient. Therefore, we suggest that different decision criteria be settled and used according to the clinical goals.

Biomarkers, Tumor↗

PubMed2004

Diagnosis of IPA in HIV: the role of the chest X-ray and radiologist.

The role of clinical information and chest film for the discrimination between invasive pulmonary aspergillosis (IPA) and its differential diagnoses in human immunodeficiency virus (HIV) infection was studied. The diagnostic performance of clinical information and chest film alone and in combination was studied for eight internists and eight radiologists with regular exposure to IPA patients. The multicenter case sample consisted of 25 patients with proven IPA and 25 with other pulmonary diseases typical for HIV. The cases were presented on a CD-ROM. Receiver operating characteristics (ROC) methodology was employed. With clinical information alone, internists achieved the highest diagnostic performance (area under curve/AUC=0.84). Viewing the chest films did not contribute to their performance (AUC=0.80, P=0.26). The radiologist's performance on the basis of viewing the chest film (AUC=0.75) increased significantly ( P=0.012) when clinical information (AUC=0.83) was supplied. IPA cases with characteristic radiological appearance were correctly identified in 90% with chest film. For radiologists with regular exposure to HIV patients, chest films hold relevant information and contribute to the determination in cases with characteristic radiological appearance. Overall and especially in cases with less characteristic radiological appearance, they have significant profit from full access to the clinical data. For internists with regular exposure to HIV patients, chest films do not provide information essential for the verification or differentiation of potential IPA.

AIDS-Related Opportunistic Infections↗

PubMed1992

Comparison between high-field-strength MR imaging and CT for screening of hepatic metastases: a receiver operating characteristic analysis.

The diagnostic performance of high-field-strength magnetic resonance (MR) imaging (1.5 T) for detection of liver metastases was compared with that of computed tomography (CT). All patients (n = 52) underwent preoperative screening for metastases by means of MR imaging with T1-weighted, proton-density-weighted, and T2-weighted pulse sequences and CT scanning with unenhanced, incremental dynamic bolus-enhanced, and delayed contrast medium-enhanced techniques. Diagnostic performance was evaluated by means of receiver operating characteristic analysis in which 800 images (400 with and 400 without lesions) and five readers (4,000 observations) were used; images were obtained from patients (n = 39) in whom the same anatomic levels were available for all MR imaging and CT studies. Direct comparison between the best MR imaging technique (T2-weighted spin-echo imaging [repetition time, 2,000 msec; echo time, 70 msec]) and the best CT technique (incremental dynamic bolus CT) showed a strong trend of superiority of T2-weighted MR imaging over incremental dynamic bolus CT. No highly statistically significant difference (P greater than or equal to .01), however, was found between these two techniques.

Esophageal Neoplasms↗

PubMed2006

[Home blood pressure self-monitoring. Influence of the mean calculation used on the diagnosis of white-coat hypertension].

OBJECTIVE: To describe the variations in the diagnosis performance of home blood pressure self-monitoring (hBPSM) with different methods for mean calculation, in order to diagnose white-coat hypertension (WCH). DESIGN: Multi-centre, descriptive, and comparative study to assess the diagnosis performance of a test method. SETTING: Four primary health care centres. PARTICIPANTS: A total of 157 recently-diagnosed, untreated patients with mild-moderate hypertension took part in the study. METHODS: The results obtained with hBPSM (3 consecutive days with readings in triplicate, morning-night) were compared with a "gold standard" out-patient blood pressure reading (OutBP). RESULTS: Systolic and diastolic BP values of the first day and first reading (morning-night) were higher than the remaining days and readings (linear trend P< .001). Results in hBPSM diagnostic performance using all readings to calculate the mean were: sensitivity (S), 47.6%; specificity (Sp), 77.4%; positive and negative predictive values (PPV and NPV), 58.8% and 68.6%, with positive and negative probability coefficients (PPC and NPC), 2.10 and 0.67. When readings with greater patient alarm reaction (first day and first reading, morning-night) were removed, greater values of S (61.9%) were obtained, albeit at expense of an excessive loss in Sp (64.5%) and without improvement in PPC (1.74). CONCLUSIONS: The diagnostic performance of hBPSM in WCH was low and failed to improve with the use of different systems to calculate mean BP.

Blood Pressure Monitoring, Ambulatory↗

PubMed1999

[The tilt-table test in assessing syncope of unknown origin: do differences exist between children and adults?].

BACKGROUND AND OBJECTIVES: Little is known about the differences between children and adults in the results of head-up tilt test. This study sought to investigate the potential differences concerning: a) the clinical profile and circumstances of spontaneous syncope; b) the overall diagnostic performance of the test, and c) the type of positive response obtained. MATERIAL AND METHODS: We studied 31 children and 123 adults with unexplained syncope. If baseline test (tilting at 70 degrees for 30 min) resulted negative, it was repeated under isoprenaline low-dose infusion. RESULTS: There were no differences in either clinical profile, except for severe traumatism more frequent in adults (25% vs. 3% in children; p < 0.05), or overall diagnostic performance (39% in children vs. 33% in adults; p = NS). However, the way the test rendered positive (via basal tilting in 92% of children vs. 50% in adults; p < 0.05) and the rate of cardioinhibitory response (42% in children vs 8% in adults; p < 0.01) were significantly different. CONCLUSIONS: In this study children, in contrast to adults, rarely have a positive response in tilting under isoprenaline infusion. They also present a much higher rate of cardio-inhibitory response than adults.

Adolescent↗

PubMed1997

Liver T2-weighted MR imaging: comparison of fast and conventional half-Fourier single-shot turbo spin-echo, breath-hold turbo spin-echo, and respiratory-triggered turbo spin-echo sequences.

PURPOSE: T2-weighted spin-echo (SE) magnetic resonance imaging in the liver was compared with four sequences: fast and conventional half-Fourier single-shot turbo SE (HASTE) and breath-hold and respiratory-triggered turbo SE. MATERIALS AND METHODS: In 58 patients with focal liver lesions, imaging was performed with a 1.5-T magnet and a phased-array coil. Images obtained with fast HASTE conventional HASTE, breath-hold turbo SE, and respiratory-triggered turbo SE were compared. Results of quantitative, qualitative, and receiver operating characteristic analyses were compared. RESULTS: Lesion-to-liver contrast for solid tumors was significantly higher with the fast HASTE and respiratory-triggered turbo SE sequences than with the conventional HASTE and breath-hold turbo SE sequences (P < .01) and for cystic lesions was significantly higher with the conventional and fast HASTE sequences than with the breath-hold or respiratory-triggered turbo SE sequences (P < .01). Artifacts were negligible on all fast and conventional HASTE images. In receiver operating characteristic analyses, diagnostic performance was significantly higher with the fast HASTE and respiratory-triggered turbo SE sequences than with the conventional HASTE and breath-hold turbo SE sequences (P < .01). CONCLUSION: Images obtained with the fast HASTE sequence were free from motion artifacts, and observer diagnostic performance was similar to that with the respiratory-triggered turbo SE sequence.

Adolescent↗

PubMed1998

Rapid screening test evaluation for microalbuminuria in diabetes mellitus.

Microalbuminuria predicts clinical nephropathy and cardiovascular disease in diabetes mellitus. This study was undertaken to evaluate a screening microalbuminuria test with the Micral test II dipstick in a general practice setting and compare whether, if three urine samples are tested, any advantage is offered over a testing single sample. Two hundred and eighty diabetic patients attending a primary health care centre were studied. The first morning urine albumin concentration was determined by dipstick over 3 consecutive days. We studied two valuation methods: Method 1. Three-sample method: the test was considered positive if albumin was equal to or above 20 mg/l in at least two of three tests; Method 2. Single-sample method: we selected the third test, i.e. the most recent urine sample; if albumin was equal to or above 20 mg/l it was considered positive. The gold standard was the albumin excretion rate measured by a nephelometric method in a 24-h urine collection. Sensitivity, specificity, predictive values and Kappa coefficient were calculated. The diagnostic performance was assessed by a receiver operating characteristic curve. Microalbuminuria was defined for different thresholds of albumin excretion rate, 15, 20, 25 and 30 microg/min: their frequency was 38, 29, 23 and 18%, respectively. For method 1, the sensitivity of Micral test II oscillated between 70-94% and the specificity between 93-83%. For method 2, the sensitivity oscillated between 64-86%, and the specificity between 88-80%. Both methods had a high diagnostic performance. The Kappa coefficient was 84 and 60% for method 1 and 2, respectively. The Micral test II is a rapid, valid and reliable method for microalbuminuria screening in diabetic patients. It constitutes an important tool for diabetic surveillance in general practice. Although the use of three samples provides better results, the use of a single sample produces acceptable results at a low cost.

Albuminuria↗

PubMed2003

Magnetic resonance cholangiopancreatography: a meta-analysis of test performance in suspected biliary disease.

BACKGROUND: Magnetic resonance cholangiopancreatography (MRCP) is one of many newer noninvasive tests that can image the biliary tree. PURPOSE: To precisely estimate the overall sensitivity and specificity of MRCP in suspected biliary obstruction and to evaluate clinically important subgroups. DATA SOURCES: MEDLINE search (January 1987 to March 2003) for studies in English or French, bibliographies, and subject matter experts. STUDY SELECTION: Studies were included if they allowed construction of 2x2 contingency tables of MRCP compared with a reasonable gold standard for at least 1 of the following: the presence, level, or cause of biliary obstruction. DATA EXTRACTION: Two independent observers graded study quality, which included consecutive enrollment, blinding, use of a single (versus composite) gold standard, and nonselective use of the gold standard. Logistic regression was used to examine the influence of publication year, quality score, proportion of patients having a "direct" gold standard, and clinical context on diagnostic performance. DATA SYNTHESIS: Of 498 studies identified, 67 were included (4711 patients). Mixed-effect models were used to estimate the sensitivity and specificity, and quantitative receiver-operating characteristic analysis was performed. Magnetic resonance cholangiopancreatography had a high overall pooled sensitivity (95% [+/-1.96 SD: spread of SD, 75% to 99%]) and specificity (97% [spread of SD, 86% to 99%]). The procedure was less sensitive for stones (92%; odds ratio, 0.51 [CI, 0.35 to 0.75]) and malignant conditions (88%; odds ratio, 0.28 [CI, 0.18 to 0.44]) than for the presence of obstruction. In addition, diagnostic performance was higher in studies that were larger, did not use consecutive enrollment, and did not use gold standard assessment for some patients. CONCLUSIONS: Magentic resonance cholangiopancreatography is a noninvasive imaging test with excellent overall sensitivity and specificity for demonstrating the level and presence of biliary obstruction; however, it seems less sensitive for detecting stones or differentiating malignant from benign obstruction.

Bile Duct Neoplasms↗

PubMed1993

Comparison of periapical and detailed narrow-beam radiography for diagnosis of periapical bone lesions.

The diagnostic performance of the detailed narrow-beam (DNB) technique of the Scanora multimodal radiography system was compared for periapical radiography for the detection of periapical bone lesions at 262 dental sites in 144 patients. Receiver operating characteristics (ROC) of both imaging modalities were analysed in relation to the ratings of five observers for the whole dentition, three dental regions, and two types of periapical lesions. ROC analysis demonstrated no overall or regional significant differences in the diagnostic performance of the two imaging modalities. The sensitivity for periapical radiography was 72% and for DNB radiography 90%, and the specificities 89% and 88%, respectively. It is concluded that DNB radiography performs as well as periapical radiography for detecting periapical bone lesions.

Adult↗

PubMed1998

[Discrepancies between the results of phlebography and Doppler ultrasonography in the diagnosis of asymptotic venous thrombosis after total hip prosthesis. False negatives of phlebography or false positives of Doppler ultrasonography].

OBJECTIVES: Assess the diagnostic performance of phlebography and discrepancies with duplex ultrasonography in screening for asymptomatic deep vein thrombosis after total hip arthroplasty. Search for arguments which would favor contributing false-negatives or false-positives to one of the two exploration methods. PATIENTS AND METHODS: The study included 24 patients who underwent the 2 explorations independently between day 7 and day 14 in a multicentric therapeutic trial of a new heparin. Discrepancies between the two techniques were recorded. Diagnostic performance of phlebography was calculated from contingency tables. The phlebograms were then reviewed with knowledge of the duplex ultrasonographic findings. The course of the venous thrombus after treatment was monitored with duplex ultrasonography. RESULTS: Phlebography allowed the diagnosis of thrombus formation in 9 patients. Ultrasonography provided the diagnosis in 14 cases out of 24. Sensitivity of phlebography compared with duplex ultrasonography was 64% (95% CI = 35.1-87.2) (9/14) and specificity was 100% (95% CI = 69.1-100) (10/10). Several localizations were not visualized with phlebography: 3 partially obstructive thrombi near the femoral junction, and 38 distal thrombi including 31 soleus thrombi (fig. 5). When the phlebograms were reviewed again, defects compatible with a partial thrombus were found for the 3 proximal localizations and for 2 of the distal localizations (fig. 1, 2, 4). None of the soleus localizations were visualized. Duplex ultrasonographic follow-up concerned 12 of the 14 patients with a thrombus identified by duplex ultrasonography involving 44 localizations. In five case, the operator was different from the operator for the initial duplex ultrasonography. Follow-up revealed: 1 new localization, 37 narrowings and 6 repermeabilizations. DISCUSSION: The coherence of the duplex ultrasonographic follow-up and the presence of images compatible with partial thrombus on the revised phlebograms which had been initially interpreted as wash out flow constitute a group of arguments suggesting that the discrepancies observed should be considered as phlebography false-negatives. This defect in the sensitivity of phlebography has been reported by others in the literature both for distal and proximal localizations.

Aged↗

PubMedDate not supplied

[ROC (receiver operating characteristics) curve: principles and application in biology].

Laboratory test's diagnostic performances are generally estimated by means of their sensibility, specificity and positive and negative predictive values. Unfortunately, these indices reflect only imperfectly the capacity of a test to correctly classify subjects into clinically relevant subgroups. The appeal to ROC (receiver operating characteristic) curve appears as a tool of choice for this evaluation. Used in the medical domain since the 60s, ROC curve is a graphic representation of the relation existing between the sensibility and the specificity of a test, calculated for all possible cut-off. It allows the determination and the comparison of the diagnostic performances of several tests. It is also used to consider the optimal cut-off of a test, by taking into account epidemiological and medical - economic data of the disease. Used in numerous medical domains, this statistical tool is easily accessible thanks to the development of computer softwares. This article exposes the principles of construction and exploitation of a ROC curve.

Adenocarcinoma↗

PubMed1998

Reliability and inter-observer agreement of dermoscopic diagnosis of melanoma and melanocytic naevi. Dermoscopy Panel.

The aim of this study was to analyse the reliability and the inter-observer agreement of dermoscopy in the diagnosis of melanocytic skin lesions. Nine dermatologists, with a different training experience and who routinely used dermoscopy in different hospitals in Italy, evaluated clinical and dermoscopy photographs of 15 melanocytic lesions (four invasive melanomas, four histologically common naevi, and seven naevi with histological atypia). A further series of dermoscopic photographs of 40 melanocytic lesions was evaluated to quantify inter-observer concordance in recognizing dermoscopic criteria. Compared to the true (histological) diagnosis, clinical diagnosis (categories: melanoma, common naevus, atypical naevus) was correct in 40% of cases (range, 27-53%). The percentage raised to 55% (40-73%) by the use of dermoscopy, with an average improvement of 15.6%. Concerning melanoma, clinical diagnosis resulted in a sensitivity of 41.9%, specificity of 77.8%, positive predictive value (PPV) of 36.1%, negative predictive value (NPV) of 81.8%. By using dermoscopy, an improvement of diagnostic performance was found (sensitivity 75%, specificity 88.8%, VPP 71.0%, VPN 90.7%). The inter-observer agreement in melanoma diagnosis, by using dermoscopy, was similar to that obtained by clinical examination (k statistics = 0.54 and 0.52, respectively). Concerning dermoscopic criteria, the best agreement among observers was found for pseudopods, a dermoscopic parameter related to the radial growth phase of melanoma. We conclude that dermoscopy is an useful tool for a non-invasive diagnosis of melanocytic skin lesions, improving the diagnostic performance compared to clinical examination.

Adult↗

PubMed2004

Frequency and characteristics of melanomas missed at a pigmented lesion clinic: a registry-based study.

To ensure the removal of all melanomas at an early phase, a number of benign lesions are currently excised for diagnostic evaluation. Nevertheless, little is known about the frequency of melanomas missed (neither recognized nor excised for diagnostic verification) by early detection practices. This study aimed to investigate the diagnostic performance of a specialized pigmented lesion clinic (PLC) through linkage with a local cancer registry. In 1997, 1741 individuals resident in the area of Florence and Prato, Italy, the catchment area of the Tuscany Cancer Registry (RTT), were consecutively examined at a specialized PLC that has been running since 1992 at the Department of Dermatology of Florence. The outcomes of dermatological consultations retrieved from PLC case notes were compared with all the diagnoses of both in situ and invasive melanoma recorded by the RTT until 31 December 1999. The performance of the PLC in detecting cutaneous melanoma was evaluated in terms of sensitivity, specificity and predictive values, with the RTT data as the gold standard. In the population examined at the PLC, 15 newly incident melanomas, all histologically demonstrated, were recorded by the RTT. In 13 of the 15 cases, excision of the lesion had been recommended by PLC staff, while two melanomas, one in situ and one level II 0.60 mm thick invasive, were missed and were subsequently excised 586 and 824 days, respectively, after the first PLC examination. The clinical and dermoscopic features of the invasive lesion were in agreement with a 'featureless' melanoma, and lacked the well-established parameters of malignancy. A total of 67 benign pigmented skin lesions were excised for diagnostic evaluation. Thus the PLC showed a sensitivity in detecting cutaneous melanoma of 86.7% (95% confidence interval [CI] 85.1-88.3%), a specificity of 95.4% (95% CI 94.3-96.3%), a positive predictive value of 13.7% (95% CI 12.1-15.3%) and a negative predictive value of 99.9% (95% CI 99.7-100.0%). The ratio of melanomas to benign skin lesions excised was 1:5.1. In conclusion, specialized examination of pigmented skin lesions at the PLC offered good level of diagnostic performance, with an acceptable cost in terms of benign lesions removed and overall a low risk of missing melanomas.

Adult↗