Intra- and Inter-operator Reproducibility Analysis of Automated Cloud-based Carotid Intima Media Thickness Ultrasound Measurement

Abstract

Introduction: Manual carotid intima media thickness (cIMT) measurements are tedious and prone to errors. Further, these measurements are subject to intra and inter-observer variability. Several studies affirm the requirement for an automated system for cIMT computation, but they still suffer from low reproducibility and lack standardisation towards clinical trials. The novelty of this study is to demonstrate the intra and interoperator reproducibility for a cloud-based automated cIMT measurement system. Aim: To demonstrate the reproducibility analysis and validation of cloud-based automated cIMT measurement systems. Materials and Methods: The reproducibility analysis was performed by two operators at three separate times (six auto readings: 1a, 1b, 1c, 2a, 2b, 2c). For validation of cloud-based cIMT measurement system, we compared the automated readings against the manual readings by the expert. The expert readings were provided by two observers who manually traced the LI/ MA borders at two separate times (four manual readings: 1a, 1b, 2a, 2b). Further, we also performed the variability analysis of the manual readings. Results: The mean Correlation Coefficients (CC) for six intra and nine inter-operator reproducibilities between the auto readings pairs were: 0.99 (p<0.001) and 0.96 (p<0.001), respectively. The mean CCs for two intra and four inter-observer variabilities between the manual readings pairs were 0.94 (p<0.001) and 0.95 (p<0.001), respectively. The accuracy computed between the mean of the six auto readings against each of the four manual readings were: 96.88%, 97.26%, 99.04%, and 98.95%, respectively. While keeping the threshold at 0.9 mm, the ROC using eight combinations give a mean AUC of 0.97±0.01. Conclusion: The proposed cloud-based automated cIMT measurement software system showed high reproducibility. The system can be adapted for routine or clinical (pharmaceutical) trial modes.

Keywords

• atherocloud
• atherosclerosis
• stroke
• trial mode