Improved Agreement between Experienced and Inexperienced Observers using a Standardized Evaluation Protocol for Cardiac Volumetry and Infarct Size Measurement

Abstract

Purpose: To study the agreement between experienced and inexperienced observers before and after training using a standardized evaluation protocol for cardiac magnetic resonance imaging (CMR) measurements of left ventricular (LV) volumes, mass and infarct size.

Materials and Methods: First, 10 CMR studies from patients with myocardial infarction were analyzed by 2 experienced and 4 inexperienced observers in respect to end-diastolic volume (EDV), end-systolic volume (ESV), ejection fraction (EF), LV mass and infarct size. Subsequently, the inexperienced observers were trained using a standardized evaluation protocol. Thereafter, all observers analyzed another 10 CMR studies.

Results: Before training the relative difference between experienced and inexperienced observers was –4.3 ± 8.2 % for EDV, –13.3 ± 14.2 % for ESV, 5.9 ± 8.2 % for EF, –12.2 ± 10.9 % for LV mass and –27.0 ± 29.0 % for infarct size in gram. After training, agreement significantly improved to 0.2 ± 8.8 % for EDV (p < 0.05), –2.1 ± 10.9 for ESV (p < 0.01), 1.5 ± 6.9 % for EF (p < 0.05), and –3.6 ± 17.1 % for infarct size (p < 0.0001), but no improvement was seen for LV mass (–11.2 ± 7.9, p = 0.64). A slice based analysis showed, that the variable inclusion of the most basal and apical slices were mainly responsible for the low agreement of the measurements before training.

Conclusion: Training using a standardized evaluation protocol significantly improved the agreement between experienced and inexperienced observers for important CMR parameters. The proposed evaluation protocol can be used for training to improve the reproducibility of CMR measurements.

Zusammenfassung

Ziel: Ziel war, die Übereinstimmung zwischen erfahrenen und unerfahrenen Untersuchern vor und nach Training unter Verwendung eines standardisierten Protokolls für die kardiale Magnetresonanztomografie (CMR) zur Auswertung der linksventrikulären (LV) Volumina, der Masse und der Infarktgröße zu untersuchen.

Material und Methoden: Zuerst wurden 10 CMRs von Infarktpatienten durch 2 erfahrene und 4 unerfahrene Untersucher in Bezug auf end-diastolisches Volumen (EDV), end-systolisches Volumen (ESV), Ejektionsfraktion (EF), LV-Masse und Infarktgröße untersucht. Anschließend wurden die unerfahrenen Untersucher unter Verwendung eines standardisierten Auswertungsprotokolls geschult. Danach werteten alle Untersucher 10 weitere CMRs aus.

Ergebnisse: Vor dem Training lagen die relativen Unterschiede zwischen den erfahrenen und unerfahrenen Untersuchern bei –4,3 ± 8,2 % für EDV, –13,3 ± 14,2 % für ESV, 5,9 ± 8,2 % für EF, –12,2 ± 10,9 % für LV-Masse und bei –27,0 ± 29,0 % für Infarktgröße in Gramm. Nach dem Training verbesserte sich die Übereinstimmung signifikant auf 0,2 ± 8,8 % für EDV (p < 0,05), –2,1 ± 10,9 für ESV (p < 0,01), 1,5 ± 6,9 % für EF (p < 0,05), und –3,6 ± 17,1 % für die Infarktgröße (p < 0,0001), aber keine Verbesserung wurde für die LV-Masse beobachtet (–11,2 ± 7,9, p = 0,64). Eine schichtbasierte Auswertung zeigte, dass der variable Einschluss der basalen und der apikalen Schicht hauptsächlich verantwortlich für die geringe Übereinstimmung vor dem Training war.

Schlussfolgerung: Training unter Anwendung eines standardisierten Auswertungsprotokolls verbesserten für wichtige LV-Parameter signifikant die Übereinstimmung zwischen erfahrenen und unerfahrenen Untersuchern. Das beschriebene Auswertungsprotokoll kann zum Training genutzt werden, um die Reproduzierbarkeit der CMR-Messungen zu erhöhen.

Key words

cardiac - MR-imaging - ischemia/infarction

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