Variability of automated carotid intima-media thickness measurements by novice operators

Carotid intima-media thickness (C-IMT) measurements provide a non-invasive assessment of sub-clinical atherosclerosis. The aim of the study was to assess the inter- and intra-observer variability of automated C-IMT measurements undertaken by two novice operators using the Panasonic CardioHealth Station. Participants were free from cardio-metabolic disease and each underwent serial bilateral C-IMT ultrasound measurements. Immediate inter operator measurement variability was calculated by comparing initial measurements taken by two operators. Immediate retest variability was calculated from two consecutive measurements and longer-term variability was assessed by conducting a further scan one week later. 50 apparently healthy participants (n=20 females), aged 26.2 ± 5.0 years were recruited. Operator 1 recorded a median (inter-quartile range) right and left-sided C-IMT of 0.471mm (0.072mm) and 0.462mm (0.047mm). Female’s right and left C-IMT was 0.442mm (0.049mm) and 0.451mm (0.063mm) respectively. The limits of agreement (LoA) for immediate inter-operator variability were -0.063 to 0.056mm (mean bias -0.003mm). Operator 1’s immediate retest intra-operator LoA were -0.057 to 0.046mm (mean bias was -0.005mm). One week LoA were -0.057 to 0.050mm (mean bias -0.003mm).Operator 2 recorded median right and left sided C-IMT of 0.467mm (0.089mm) and 0.458mm (0.046mm) for males respectively whilst female measurements were 0.441mm (0.052mm) and 0.444mm (0.054mm) respectively. Operator 2’s intra-operator immediate retest LoA were -0.056 to 0.056 (mean bia