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Influence of phase correction of late gadolinium enhancement images on scar signal quantification in patients with ischemic and non-ischemic cardiomyopathy.

Stirrat J, Joncas SX, Salerno M, Drangova M, White J - J Cardiovasc Magn Reson (2015)

Bottom Line: This was performed on both MIR and PSIR images and values compared using linear regression and Bland-Altman analyses.FWHM analysis demonstrated good correlation in the ischemic population (N = 40, r = 0.83, p < 0.0001).Scar quantification using phase corrected (PSIR) images achieves values highly correlated to those obtained on non-corrected (MIR) images.

View Article: PubMed Central - PubMed

Affiliation: Robarts Research Institute, University of Western Ontario, London, Ontario, Canada. jstirrat@imaging.robarts.ca.

ABSTRACT

Background: Myocardial fibrosis imaging using late gadolinium enhancement (LGE) cardiac magnetic resonance (CMR) has been validated as a quantitative predictive marker for response to medical, surgical, and device therapy. To date, all such studies have examined conventional, non-phase corrected magnitude images.  However, contemporary practice has rapdily adopted phase-corrected image reconstruction. We sought to investigate the existence of any systematic bias between threshold-based scar quantification performed on conventional magnitude inversion recovery (MIR) and matched phase sensitive inversion recovery (PSIR) images.

Methods: In 80 patients with confirmed ischemic (N = 40), or non-ischemic (n = 40) myocardial fibrosis, and also in a healthy control cohort (N = 40) without fibrosis, myocardial late enhancement was quantified using a Signal Threshold Versus Reference Myocardium technique (STRM) at ≥2, ≥3, and ≥5 SD threshold, and also using the Full Width at Half Maximal (FWHM) technique. This was performed on both MIR and PSIR images and values compared using linear regression and Bland-Altman analyses.

Results: Linear regression analysis demonstrated excellent correlation for scar volumes between MIR and PSIR images at all three STRM signal thresholds for the ischemic (N = 40, r = 0.96, 0.95, 0.88 at 2, 3, and 5 SD, p < 0.0001 for all regressions), and non ischemic (N = 40, r = 0.86, 0.89, 0.90 at 2, 3, and 5 SD, p < 0.0001 for all regressions) cohorts. FWHM analysis demonstrated good correlation in the ischemic population (N = 40, r = 0.83, p < 0.0001). Bland-Altman analysis demonstrated a systematic bias with MIR images showing higher values than PSIR for ischemic (3.3 %, 3.9 % and 4.9 % at 2, 3, and 5 SD, respectively), and non-ischemic (9.7 %, 7.4 % and 4.1 % at ≥2, ≥3, and ≥5 SD thresholds, respectively) cohorts. Background myocardial signal measured in the control population demonstrated a similar bias of 4.4 %, 2.6 % and 0.7 % of the LV volume at 2, 3 and 5 SD thresholds, respectively. The bias observed using FWHM analysis was -6.9 %.

Conclusions: Scar quantification using phase corrected (PSIR) images achieves values highly correlated to those obtained on non-corrected (MIR) images. However, a systematic bias exists that appears exaggerated in non-ischemic cohorts. Such bias should be considered when comparing or translating knowledge between MIR- and PSIR-based imaging.

No MeSH data available.


Related in: MedlinePlus

Linear regression and Bland-Altman analyses comparing myocardial late enhancement volume using MIR and PSIR for FWHM-based analysis. Late enhancement is reported as percent of total LV myocardial volume at 2, 3, and 5 SD from the mean signal intensity of normal reference myocardium. Left: Linear regression analysis. Values indicate the mean difference of MIR-based scar volume quantification relative to PSIR. Right: Bland-Altman analysis. Long dashed lines represent bias, dotted lines represent 95 % confidence intervals
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Fig4: Linear regression and Bland-Altman analyses comparing myocardial late enhancement volume using MIR and PSIR for FWHM-based analysis. Late enhancement is reported as percent of total LV myocardial volume at 2, 3, and 5 SD from the mean signal intensity of normal reference myocardium. Left: Linear regression analysis. Values indicate the mean difference of MIR-based scar volume quantification relative to PSIR. Right: Bland-Altman analysis. Long dashed lines represent bias, dotted lines represent 95 % confidence intervals

Mentions: Among those with ischemic injury, scar signal quantification was repeated using the FWHM technique, as previously described [20]. Linear regression analysis demonstrated a good correlation between MIR and PSIR derived total scar volumes (r = 0.83, p < 0.0001). Bland-Altman analysis demonstrated a systematic bias between MIR and PSIR derived measurements of total myocardial scar volume. However, in contrast to STRM-based imaging, the mean bias demonstrated a reduction in total scar volume estimates using MIR-based images versus PSIR-based images, and was estimated to be 6.9 % of the LV mass (Fig. 4).Fig. 4


Influence of phase correction of late gadolinium enhancement images on scar signal quantification in patients with ischemic and non-ischemic cardiomyopathy.

Stirrat J, Joncas SX, Salerno M, Drangova M, White J - J Cardiovasc Magn Reson (2015)

Linear regression and Bland-Altman analyses comparing myocardial late enhancement volume using MIR and PSIR for FWHM-based analysis. Late enhancement is reported as percent of total LV myocardial volume at 2, 3, and 5 SD from the mean signal intensity of normal reference myocardium. Left: Linear regression analysis. Values indicate the mean difference of MIR-based scar volume quantification relative to PSIR. Right: Bland-Altman analysis. Long dashed lines represent bias, dotted lines represent 95 % confidence intervals
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4528363&req=5

Fig4: Linear regression and Bland-Altman analyses comparing myocardial late enhancement volume using MIR and PSIR for FWHM-based analysis. Late enhancement is reported as percent of total LV myocardial volume at 2, 3, and 5 SD from the mean signal intensity of normal reference myocardium. Left: Linear regression analysis. Values indicate the mean difference of MIR-based scar volume quantification relative to PSIR. Right: Bland-Altman analysis. Long dashed lines represent bias, dotted lines represent 95 % confidence intervals
Mentions: Among those with ischemic injury, scar signal quantification was repeated using the FWHM technique, as previously described [20]. Linear regression analysis demonstrated a good correlation between MIR and PSIR derived total scar volumes (r = 0.83, p < 0.0001). Bland-Altman analysis demonstrated a systematic bias between MIR and PSIR derived measurements of total myocardial scar volume. However, in contrast to STRM-based imaging, the mean bias demonstrated a reduction in total scar volume estimates using MIR-based images versus PSIR-based images, and was estimated to be 6.9 % of the LV mass (Fig. 4).Fig. 4

Bottom Line: This was performed on both MIR and PSIR images and values compared using linear regression and Bland-Altman analyses.FWHM analysis demonstrated good correlation in the ischemic population (N = 40, r = 0.83, p < 0.0001).Scar quantification using phase corrected (PSIR) images achieves values highly correlated to those obtained on non-corrected (MIR) images.

View Article: PubMed Central - PubMed

Affiliation: Robarts Research Institute, University of Western Ontario, London, Ontario, Canada. jstirrat@imaging.robarts.ca.

ABSTRACT

Background: Myocardial fibrosis imaging using late gadolinium enhancement (LGE) cardiac magnetic resonance (CMR) has been validated as a quantitative predictive marker for response to medical, surgical, and device therapy. To date, all such studies have examined conventional, non-phase corrected magnitude images.  However, contemporary practice has rapdily adopted phase-corrected image reconstruction. We sought to investigate the existence of any systematic bias between threshold-based scar quantification performed on conventional magnitude inversion recovery (MIR) and matched phase sensitive inversion recovery (PSIR) images.

Methods: In 80 patients with confirmed ischemic (N = 40), or non-ischemic (n = 40) myocardial fibrosis, and also in a healthy control cohort (N = 40) without fibrosis, myocardial late enhancement was quantified using a Signal Threshold Versus Reference Myocardium technique (STRM) at ≥2, ≥3, and ≥5 SD threshold, and also using the Full Width at Half Maximal (FWHM) technique. This was performed on both MIR and PSIR images and values compared using linear regression and Bland-Altman analyses.

Results: Linear regression analysis demonstrated excellent correlation for scar volumes between MIR and PSIR images at all three STRM signal thresholds for the ischemic (N = 40, r = 0.96, 0.95, 0.88 at 2, 3, and 5 SD, p < 0.0001 for all regressions), and non ischemic (N = 40, r = 0.86, 0.89, 0.90 at 2, 3, and 5 SD, p < 0.0001 for all regressions) cohorts. FWHM analysis demonstrated good correlation in the ischemic population (N = 40, r = 0.83, p < 0.0001). Bland-Altman analysis demonstrated a systematic bias with MIR images showing higher values than PSIR for ischemic (3.3 %, 3.9 % and 4.9 % at 2, 3, and 5 SD, respectively), and non-ischemic (9.7 %, 7.4 % and 4.1 % at ≥2, ≥3, and ≥5 SD thresholds, respectively) cohorts. Background myocardial signal measured in the control population demonstrated a similar bias of 4.4 %, 2.6 % and 0.7 % of the LV volume at 2, 3 and 5 SD thresholds, respectively. The bias observed using FWHM analysis was -6.9 %.

Conclusions: Scar quantification using phase corrected (PSIR) images achieves values highly correlated to those obtained on non-corrected (MIR) images. However, a systematic bias exists that appears exaggerated in non-ischemic cohorts. Such bias should be considered when comparing or translating knowledge between MIR- and PSIR-based imaging.

No MeSH data available.


Related in: MedlinePlus