Novel approach to artefact detection and the definition of normal ranges of segmental strain and strain-rate values

Abstract

AimsStrain artefacts are known to hamper the correct interpretation of segmental strain and strain-rate (S/SR). Defining the normal ranges of myocardial segmental deformation is important in clinical studies and routine echocardiographic practice. In order to define artefact-free normal ranges for segmental longitudinal S/SR parameters, we investigated the extent to which different types of artefacts and their segmental localisation in the three different myocardial layers created a bias in the results of echocardiographic strain measurements.MethodsThe study included echocardiograms from men and women aged 40–69 years from two population-based studies, namely the Know Your Heart study (Russia) and the Tromsø Study (Norway). Of the 2207 individuals from these studies, 840 had normal results, defined as the absence of hypertension or indicators of any cardiovascular disease. Two-dimensional (2D) global and segmental S/SR of the three myocardial layers were analysed using speckle tracking echocardiography. Artefacts were assessed with two different methods: visual identification of image-artefacts and a novel conceptual approach of ‘curve-artefacts’ or unphysiological strain-curve formation.ResultsSegmental strain values were found to have significantly reduced in the presence of strain-curve artefacts (14.9%±5.8% towards −20.7%±4.9%), and increased with the foreshortening of the 2D image. However, the individual global strain values were not substantially altered by discarding segmental artefacts. Reduction due to artefacts was observed in all segments, layers, systolic and diastolic strain, and SR. Thus, we presented normal ranges for basal-septal, basal, medial and apical segment groups after excluding artefacts.ConclusionStrain-curve artefacts introduce systematic errors, resulting in reduced segmental S/SR values. In terms of artefact-robust global longitudinal strain, the detection of curve-artefacts is crucial for the correct interpretation of segmental S/SR patterns. Intersegmental S/SR gradients and artefacts need to be considered for the correct definition of normalcy and pathology.

Influence of hypertension on systolic and diastolic left ventricular function including segmental strain and strain rate

“…Artifact detection was used to identify distorted echocardiographic records that were to be excluded from analysis. The identification of strain‐curve artifacts was based on artifact detection by visual assessment of the strain curves and was described in detail in a previous publication 14 on the same study population. Strain curve artifacts were subjectively assessed using these previously described features and classified as 1 “blunted curves” (a reduced or even positive strain in the start of the cycle, mirrored by a similar curve‐formation at the end of systole), 2 “diastolic mismatch” (late diastolic strain curve significantly deviating towards 0 or positive values compared to the late diastolic strain‐curves of other segments), and 3 “floating” (segmental strain curves with several negative and positive peaks without correspondence with timing or configuration of other segments).…”

“…The intra‐ and inter‐observer variabilities have been previously reported 14 . For intra‐and inter‐observer variability in strain and SR measurements, the same observer repeatedly analyzed 135 randomly selected echocardiographic records comprising 1620 segments within 6−12 months from the initial analysis.…”

“…reported. 14 For intra-and inter-observer variability in strain and SR measurements, the same observer repeatedly analyzed 135 randomly selected echocardiographic records comprising 1620 segments within 6−12 months from the initial analysis. The same data were reanalyzed by a second experienced observer.…”

Relation between hypertension and systolic and diastolic left ventricular function including segmental strain and strain rate

“…Artifact detection was used to identify distorted echocardiographic records that were to be excluded from analysis. The identification of strain-curve artifacts was based on artifact detection by visual assessment of the strain curves and was described in detail in a previous publication (12) on the same study population. Strain curve artifacts were subjectively assessed using these previously described features and classified as (1) "blunted curves" (a reduced or even positive strain in the start of the cycle, mirrored by a similar curveformation at the end of systole), ( 2) "diastolic mismatch" (late diastolic strain curve significantly deviating towards 0 or positive values compared to the late diastolic strain-curves of other segments), and (3) "floating" (segmental strain curves with several negative and positive peaks without correspondence with timing or configuration of other segments).…”

“…The intra-and inter-observer variabilities have been previously reported (12). For intra-and inter-observer variability in strain and SR measurements, the same observer repeatedly analyzed 135 randomly selected echocardiographic records comprising 1620 segments within 6-12 months from the initial analysis.…”