Related Experiment Video
Updated: Apr 3, 2026
Author Spotlight: Advancing Cardiovascular Imaging - Introducing the Spatially Weighted Calcium Score for Early Disease Detection
Published on: September 22, 2023
Coronary Artery Aneurysm Measurement and Z Score Variability in Kawasaki Disease
Christina Ronai1, Akiko Hamaoka-Okamoto2, Annette L Baker2
1Department of Cardiology, Boston Children's Hospital, Boston, Massachusetts; Department of Pediatrics, Harvard Medical School, Boston, Massachusetts.
Insights
Coronary artery Z scores for Kawasaki disease show high measurement agreement but significant formula variability, impacting clinical decisions, especially in larger vessel dimensions.
Area of Science:
- Pediatric Cardiology
- Medical Imaging Analysis
- Kawasaki Disease Research
Background:
- Coronary artery (CA) Z scores are crucial for managing Kawasaki disease, guiding treatment and follow-up.
- Variability in Z score calculations can influence clinical decisions.
Purpose of the Study:
- To assess the reproducibility of CA measurements.
- To evaluate the variability of Z score calculations using different formulas.
- To determine the impact of this variability on clinical management.
Main Methods:
- Two echocardiographers measured CA dimensions in 41 Kawasaki disease patients.
- Inter- and intraobserver reliability of measurements were calculated.
- CA Z scores were derived using three common formulas and compared.
Main Results:
- High inter- and intraobserver reliability for LAD and RCA measurements (ICC >93%).
- Lower reliability for left main CA measurements (ICC 73-80%).
- Z score calculations varied significantly with different formulas, particularly for larger CA dimensions, altering management in up to 50% of patients.
Conclusions:
- While CA measurements are reliable, Z score formula choice significantly impacts results, especially for larger dimensions.
- Discrepancies in Z score calculators can lead to different clinical management strategies in Kawasaki disease.
Background:
Coronary artery (CA) Z scores are commonly used for clinical decisions in Kawasaki disease, including treatment, anticoagulation, and duration and frequency of follow-up. The aim of this study was to evaluate CA measurement reproducibility, Z score calculation variability, and the impact of variability on management.
Methods:
Twenty-one patients with Kawasaki disease with right CA (RCA) or left anterior descending CA (LAD) Z scores of 1.5 to 3 (group 1) were randomly selected, and all patients with Kawasaki disease with Z scores of 7 to 14 for either the RCA or LAD (n = 20; group 2) were included from March 2008 to May 2014. Two echocardiographers measured left main CA, LAD, and RCA dimensions. The inter- and intraobserver reliability of absolute measurements was calculated, and the CA Z scores derived from three commonly used formulas were compared.
Results:
Median age at echocardiography was 1.2 years (range, 0.2-11.5 years), and 68% of subjects (n = 28) were male. Interobserver reliability was high for the LAD (intraclass correlation coefficient [ICC], 96.79%) and RCA (ICC, 93.31%) and lower for the left main CA (ICC, 73.54%). Intraobserver reliability was also high for the LAD and RCA (ICC, 99.08% and 97.74%) and lower for the left main CA (ICC, 80.88%). Calculated Z scores were similar among the three formulas for group 1 but varied markedly in group 2. Calculated Z scores using the same CA measurement in each of the three formulas resulted in different clinical management in up to seven of 21 group 1 patients (22%) and in up to 10 of 20 group 2 patients (50%).
Conclusions:
Although CA measurements have high inter- and intraobserver agreement, CA Z scores vary dramatically on the basis of the Z score formula at larger CA dimensions. Discrepancies in CA Z score calculators may affect clinical decision making.
Related Concept Videos
01:25Imaging Studies for Cardiovascular System VI: Calcium -Scoring CT
01:21Aneurysm II: Clinical Manifestations and Diagnostic Studies
01:30Acute Coronary Syndrome III: Diagnostic Studies
01:27Atherosclerosis II: Clinical Manifestations and Diagnostic Tests
01:20Imaging Studies for Cardiovascular System III: X-Ray
Definition and Purpose
An X-ray, or radiograph, is a non-invasive method that uses ionizing radiation to take images of internal structures. It is mainly used in cardiac imaging to examine the heart, lungs, and major blood vessels, aiming to identify abnormalities in the heart's size, shape, and position, such as heart failure, congenital defects, and vascular...
01:26Coronary Artery Disease II: Pathophysiology