Comparison of semi-automated methods to quantify infarct size and area at risk by cardiovascular magnetic resonance imaging at 1.5T and 3.0T field strengths

Abstract

BackgroundThere is currently no gold standard technique for quantifying infarct size (IS) and ischaemic area-at-risk (AAR [oedema]) on late gadolinium enhancement imaging (LGE) and T2-weighted short tau inversion recovery imaging (T2w-STIR) respectively. This study aimed to compare the accuracy and reproducibility of IS and AAR quantification on LGE and T2w-STIR imaging using Otsu’s Automated Technique (OAT) with currently used methods at 1.5T and 3.0T post acute ST-segment elevation myocardial infarction (STEMI).MethodsTen patients were assessed at 1.5T and 10 at 3.0T. IS was assessed on LGE using 5–8 standard-deviation thresholding (5-8SD), full-width half-maximum (FWHM) quantification and OAT. AAR was assessed on T2w-STIR using 2SD and OAT. Accuracy was assessed by comparison with manual quantification. Interobserver and intraobserver variabilities were assessed using Intraclass Correlation Coefficients and Bland-Altman analysis. IS using each technique was correlated with left ventricular ejection fraction (LVEF).ResultsFWHM and 8SD-derived IS closely correlated with manual assessment at both field strengths (1.5T: 18.3 ± 10.7% LV Mass [LVM] with FWHM, 17.7 ± 14.4% LVM with 8SD, 16.5 ± 10.3% LVM with manual quantification; 3.0T: 10.8 ± 8.2% LVM with FWHM, 11.4 ± 9.0% LVM with 8SD, 11.5 ± 9.0% LVM with manual quantification). 5SD and OAT overestimated IS at both field strengths. OAT, 2SD and manually quantified AAR closely correlated at 1.5T, but OAT overestimated AAR compared with manual assessment at 3.0T. IS and AAR derived by FWHM and OAT respectively had better reproducibility compared with manual and SD-based quantification. FWHM IS correlated strongest with LVEF.ConclusionsFWHM quantification of IS is accurate, reproducible and correlates strongly with LVEF, whereas 5SD and OAT overestimate IS. OAT accurately assesses AAR at 1.5T and with excellent reproducibility. OAT overestimated AAR at 3.0T and thus cannot be recommended as the preferred method for AAR quantification at 3.0T.Electronic supplementary materialThe online version of this article (doi:10.1186/s13104-015-1007-1) contains supplementary material, which is available to authorized users.

The randomised Complete versus Lesion-only PRimary percutaneous coronary Intervention Trial: Cardiovascular Magnetic Resonance imaging substudy (CvLPRIT-CMR)

“…This is most likely because of the use of the FWHM technique to quantify IS, which gives lower ISs than commonly used thresholding techniques. 85,86 These findings confirm that the non-IRA intervention at the time of the PPCI does not lead to increased total IS. In the main CvLPRIT, 80 CR resulted in a significantly reduced HR for the 12-month combined MACEs, despite the greater prevalence of CMR imaging-detected type 4a MI shown in the current results.…”

Relationship of Myocardial Strain and Markers of Myocardial Injury to Predict Segmental Recovery After Acute ST-Segment–Elevation Myocardial Infarction

“…[10][11][12]16 Infarct Characterization Edema (area-at-risk [AAR]) and infarct were quantified using cvi42 v4.1 on T2w-STIR and LGE imaging, using Otsu's Automated Method and full-width half-maximum thresholding, respectively, as previously described by our group. 25 Hypointense regions within enhancement on LGE and T2w-STIR imaging were included, corresponding to MVO and IMH, respectively, and expressed as present or absent for each of the 16 segments. SEE was calculated as percentage enhanced area for each myocardial segment (SEE=100 × [segmental enhanced area/segmental area]).…”

“…25 Hypointense regions within enhancement on LGE and T2w-STIR imaging were included, corresponding to MVO and IMH, respectively, and expressed as present or absent for each of the 16 segments. SEE was calculated as percentage enhanced area for each myocardial segment (SEE=100 × [segmental enhanced area/segmental area]).…”

Impact of microvascular obstruction on semiautomated techniques for quantifying acute and chronic myocardial infarction by cardiovascular magnetic resonance

“…Several different techniques have been proposed for quantifying MI size including manual contouring7 and semiautomated thresholding techniques such as a signal intensity threshold of 5-SD8 or 6-SD9 above the normal remote myocardium, the Otsu technique,10 and the full width half maximum (FWHM)11 12 technique. The consensus document from the Society for Cardiovascular Magnetic Resonance Board of Trustees Task Force on Standardised Post Processing recommends the semiautomated threshold technique of 5-SD for MI size quantification as it may improve reproducibility.…”

“…The consensus document from the Society for Cardiovascular Magnetic Resonance Board of Trustees Task Force on Standardised Post Processing recommends the semiautomated threshold technique of 5-SD for MI size quantification as it may improve reproducibility. Manual contouring is considered the gold standard7 13 but may be time-consuming12 14 and subjective. FWHM has emerged as the technique having the lowest variability11 12 but others have shown FWHM to underestimate acute and chronic MI size 10…”