Information and observer disagreement in histopathology

1994 ◽  
Vol 25 (2) ◽  
pp. 123-128 ◽  
Author(s):  
J.A. MORRIS
Keyword(s):  
Observer Disagreement

Abstract 96: CTP-Mismatch Maps Improve Interobserver Agreement

Stroke ◽  
2012 ◽  
Vol 43 (suppl_1) ◽  
Author(s):  
Waimei A Tai ◽  
Archana Purushotham ◽  
Matus Straka ◽  
Rebecca M Sugg ◽  
Naveed Akhtar ◽  
...  
Keyword(s):  
Acute Stroke ◽  
Ct Perfusion ◽  
Interobserver Reliability ◽  
Observer Agreement ◽  
Absolute Difference ◽  
Stroke Therapy ◽  
Adequate Quality ◽  
Ischemic Core ◽  
Observer Disagreement ◽  
Acute Stroke Therapy

Introduction: The use of mismatch between the ischemic core and penumbra to select patients who are likely to benefit from acute stroke therapy has gained popularity. Interpretation of the ischemic core and penumbra on standard CT-perfusion (CTP) maps is subjective. This may lead to variability among physicians in the decision if a patient is a good candidate for acute stroke therapy. A CTP-Mismatch map with outlines of the ischemic core and penumbra could limit this variability. The goal of this study was to determine if inter-observer agreement regarding a patient’s suitability for acute stroke therapy improves with the use of a CTP-Mismatch map. The figure shows a typical CTP-Mismatch map. Methods: Ninety-six consecutive patients evaluated with CTP prior to intra-arterial therapy at St. Lukes Hospital in 2008-09 were included. 79 patients had adequate quality CTP for this analysis. Standard CTP maps (CBV, CBF, MTT, and Tmax) and a CTP-Mismatch map were generated with a fully automated program for processing of CTP source images (RAPID). RAPID assessed the ischemic core using a CBF threshold <30% of the contralateral hemisphere (rCBF<30%). The ischemic penumbra was defined by a Tmax threshold of >6 sec (Tmax>6s). The standard CTP maps and the CTP-Mismatch map were independently analyzed by two vascular neurologists in a blinded fashion. The raters assessed a patient's suitability for intra-arterial therapy based on the following mismatch criteria: (1) a ratio between (Tmax>6s) and (rCBF<30%) volumes >1.8 and (2) an absolute difference between (Tmax>6s) and (CBF<30%) volumes >15ml. Interobserver reliability was assessed with Cohen’s kappa. Results: When assessment of suitability for intra-arterial therapy was based on interpretation of standard CTP maps, the two raters agreed in 58 of 79 patients (kappa=0.46; 95% CI=0.24-0.60). The agreement between observers improved when suitability was determined using CTP-Mismatch maps (agreement in 76 of 79 cases; kappa=0.92; 95% CI=0.75-0.92; p<0.001 for difference between kappa values). The 3 cases with inter-observer disagreement had artifact on the CTP-Mismatch map. Following concensus adjudication of these 3 cases, 40 of the 79 patients (51%) were deemed suitable candidates for acute stroke therapy. Conclusion: CTP-Mismatch maps with estimates of ischemic core and penumbra volumes markedly improve inter-observer agreement regarding assessment of suitability for acute stroke therapy. Such maps, which can be generated automatically, may help standardize decision making algorithms for evaluation of potential intra-arterial therapy candidates.

Contrast Venography, the Gold Standard for the Diagnosis of Deep-Vein Thrombosis: lmprovement in Observer Agreement

1992 ◽  
Vol 67 (01) ◽  
pp. 08-12 ◽  
Author(s):  
Anthonie W A Lensing ◽  
Harry R Büller ◽  
Paolo prandoni ◽  
David Batchelor ◽  
Andre H M Molenaar ◽  
...  
Keyword(s):  
Deep Vein Thrombosis ◽  
Contrast Material ◽  
Observer Agreement ◽  
Test Results ◽  
Main Study ◽  
Vein Thrombosis ◽  
Diagnostic Management ◽  
Deep Vein ◽  
Observer Disagreement ◽  
Test Result

SummaryTo determine whether the Rabinov-Paulin or the long-leg venography technique should be preferred in the diagnostic management of patients with clinically suspected deep-vein thrombosis, two independent experienced radiologists blindly assessed two different series of venograms of consecutive outpatients with clinically suspected deep-vein thrombosis. Venograms were obtained from two outpatient clinics of primary referral centres. In one centre the venograms were performed according to the technique of Rabinov and Paulin with the use of 100 ml of radiographic material and spot films of the calf, popliteal and more proximal veins. In the other centre, long-leg films were obtained after the administration of 150 ml of contrast material. The percentage venograms adjudicated as inadequate by at least one radiologist and inter-observer disagreement for both series were used as the main study outcome measures. Prior to the study, both radiologists agreed on the standardized criteria for a normal, abnormal and inadequate test result using a separate set of films.An inadequacy rate of 20% was found for the Rabinov-Paulin venography series (n = 123), whereas only 2% of the L26long-leg films were inadequate for interpretation (p <0.001). The interobserver disagreement for inadequacy, presence or absence of deep-vein thrombosis was 2I% for the Rabinov and Paulin venograms and 4o/" for the long-leg films (kappa, 0.65 and 0.92; 95% confidence intervals: 0.53 to 0.77 and 0.84 to 0.99, respectively; p <0.002).We conclude that the long-leg method is superior to the Rabinov-Paulin method in the venographic diagnosis of deep-vein thrombosis in symptomatic outpatients since noninterpretable test results are rarely observed and it reduces both unnecessary treatment of patients without deep-vein thrombosis and limits the undertreatment of patients with the disease.

Observer Disagreement in Rating Neurologic Impairment in Multiple Sclerosis: Facts and Consequences

1991 ◽  
Vol 31 (2) ◽  
pp. 117-119 ◽  
Author(s):  
M.H. Verdier-Taillefer ◽  
M. Zuber ◽  
O. Lyon-Caen ◽  
M. Clanet ◽  
O. Gout ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
Neurologic Impairment ◽  
Observer Disagreement

scholarly journals Balancing Speed and Accuracy in Cardiac Magnetic Resonance Function Post-Processing: Comparing 2 Levels of Automation in 3 Vendors to Manual Assessment

Diagnostics ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1758
Author(s):  
Gert J.H. Snel ◽  
Sharon Poort ◽  
Birgitta K. Velthuis ◽  
Vincent M. van Deursen ◽  
Christopher T. Nguyen ◽  
...  
Keyword(s):  
Cardiac Magnetic Resonance ◽  
Magnetic Resonance ◽  
Software Package ◽  
Post Processing ◽  
End Diastolic Volume ◽  
Manual Contour ◽  
Level 1 ◽  
Observer Disagreement ◽  
Speed And Accuracy ◽  
Level 2

Automating cardiac function assessment on cardiac magnetic resonance short-axis cines is faster and more reproducible than manual contour-tracing; however, accurately tracing basal contours remains challenging. Three automated post-processing software packages (Level 1) were compared to manual assessment. Subsequently, automated basal tracings were manually adjusted using a standardized protocol combined with software package-specific relative-to-manual standard error correction (Level 2). All post-processing was performed in 65 healthy subjects. Manual contour-tracing was performed separately from Level 1 and 2 automated analysis. Automated measurements were considered accurate when the difference was equal or less than the maximum manual inter-observer disagreement percentage. Level 1 (2.1 ± 1.0 min) and Level 2 automated (5.2 ± 1.3 min) were faster and more reproducible than manual (21.1 ± 2.9 min) post-processing, the maximum inter-observer disagreement was 6%. Compared to manual, Level 1 automation had wide limits of agreement. The most reliable software package obtained more accurate measurements in Level 2 compared to Level 1 automation: left ventricular end-diastolic volume, 98% and 53%; ejection fraction, 98% and 60%; mass, 70% and 3%; right ventricular end-diastolic volume, 98% and 28%; ejection fraction, 80% and 40%, respectively. Level 1 automated cardiac function post-processing is fast and highly reproducible with varying accuracy. Level 2 automation balances speed and accuracy.

OBSERVER DISAGREEMENT IN PHYSICAL SIGNS OF THE RESPIRATORY SYSTEM

The Lancet ◽  
1965 ◽  
Vol 286 (7409) ◽  
pp. 412-413 ◽  
Author(s):  
H.C. Smyllie ◽  
L.M. Blendis ◽  
P. Armitage
Keyword(s):  
Respiratory System ◽  
Observer Disagreement

MR Imaging of Large Multinodular Goiters:Observer Agreement on Volume Versus Observer Disagreement on Dimensions of the Involved Trachea

2002 ◽  
Vol 179 (1) ◽  
pp. 259-266 ◽  
Author(s):  
Steen J. Bonnema ◽  
Peter B. Andersen ◽  
Dorthe U. Knudsen ◽  
Laszlo Hegedüs
Keyword(s):  
Mr Imaging ◽  
Volume Versus ◽  
Observer Disagreement

Ventilation-Perfusion Lung Scanning and the Diagnosis of Pulmonary Embolism: Improvement of Observer Agreement by the Use of a Lung Segment Reference Chart

1992 ◽  
Vol 68 (03) ◽  
pp. 245-249 ◽  
Author(s):  
Anthonie W A Lensing ◽  
Edwin J R van Beek ◽  
Christine Demers ◽  
Monique M C Tiel-van Buul ◽  
Valerie Yakemchuk ◽  
...  
Keyword(s):  
Pulmonary Embolism ◽  
Nuclear Medicine ◽  
High Probability ◽  
Observer Agreement ◽  
Diagnostic Approach ◽  
Suspected Pulmonary Embolism ◽  
Nuclear Medicine Physician ◽  
Medicine Physician ◽  
Lung Segment ◽  
Observer Disagreement

Summary Objective. To test the hypothesis that the systematic use of a lung segment reference chart can improve the inter- and intra-observer agreement for the interpretation of ventilation-perfusion lung scans. Design. A randomized trial. Study population. Ventilation-perfusion lung scans were obtained in a series of 220 consecutive patients with clinically suspected pulmonary embolism. Intervention. Ventilation-perfusion scans were randomly allocated to one of two series each consisting of 110 ventilation-perfusion lung scans. The first series of lung scans was interpreted according to the routine diagnostic approach, and the second series was interpreted with the mandatory use of a lung segment reference chart on which observed ventilation and perfusion defects were drawn. The two nuclear medicine physicians agreed a priori on the diagnostic criteria of the classification scheme. Measurements. Lung scans were classified as normal, non-high probability, or high probability for pulmonary embolism. The extent of disagreement between the nuclear medicine physicians (inter-observer disagreement) and the lack of internal consistency of each nuclear medicine physician (intra-observer disagreement) was assessed by the percentage disagreement and by kappa statistic. Results. Inter-observer disagreement which was 20% in the first series, decreased significantly in the second series to 7%; P = 0.003. Intra-observer disagreement for the first series was 10% and 22% for the nuclear medicine physicians, respectively. Intra-observer disagreement for the second series of lung scans decreased significantly for one nuclear medicine physician (intra-observer disagreement, 0%; P <0.01), whereas intra-observer disagreement was reduced to 10% for the other nuclear medicine physician (P = 0.09). Conclusion. Inter- and intra-observer disagreement were significantly reduced when two nuclear medicine specialists interpreted ventilation-perfusion lung scans according to the routine diagnostic approach plus the use of a lung segment reference chart. The use of the lung segment reference chart for the interpretation of lung scans is likely to improve the management of patients with clinically suspected pulmonary embolism.

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