RPS 703 - Measuring myocardial extracellular volume (ECV) with CT and MR

Author Block: J. Liang, Z. Sheng, W. chen, X. Chen, D. Mu; Nanjing/CN
Purpose or Learning Objective: To explore clinical feasibility of using iodine-based extracellular volume (ECV) to assess myocardium for the patients underwent percutaneous coronary intervention (PCI) in comparison with MR results.
Methods or Background: A total of 21 patients who have received PCI were prospectively enrolled for this study. All these patients underwent both cardiac dual-layer spectral detector CT (SDCT) and MR scans for PCI follow-up check. Myocardial ECVCT was calculation from iodine map and ECVMR was calculated from T1 mapping. Image quality (IQ) of both CT and MR images were firstly assessed using 4-point like scale and by two radiologists independently and any patients with a score less than 2 were excluded for final analysis. Pearson test was performed to analyze the correlation between ECVCT and ECVMR and Bland‑Altman plot was used for the consistency analysis. Intraclass correlation coefficient (ICC) was performed to evaluate the consistency between the two radiologists.
Results or Findings: A total of 19 patients completed both CT & MR cardiac scans and three patients (two patients with poor IQ of MR, one patient with discontinues coronary artery from CT) were excluded for this study. The mean image quality (IQ) score of CT and MR images were 3.81±0.40 and 3.25±0.58 respectively and interobserver agreement was good (ICC=0.93 for CT and 0.92 for MR). The average of ECVCT and ECVMR was 35.93±9.73% and 33.89±7.51% with good correlation (r=0.79, P<0.001). Bland‑Altman analysis showed that the result of ECVCT was 2.04% (95% confidence interval: 9.56%-13.64%) overestimated compared with ECVMR.
Conclusion: Iodine-based ECV derived from SDCT has high correlation with ECV calculated from MR which could be clinical feasible to evaluate myocardium recovery status for the patient underwent PCI.
Limitations: Not applicable.
Ethics committee approval: No.:2018-046-01.
Funding for this study: Not applicable.

Author Block: J. Deng, D. Han, Z. Li, W. Gao, W. Chen; Kunming/CN
Purpose or Learning Objective: To assess the potential of myocardial extracellular volume fraction (ECV) from late iodine enhancement (LIE) using dual-energy computed tomography for disease risk stratification in patients with non-ischemic heart failure (NIHF).
Methods or Background: 25 patients with NIHF (52±13 years, 7 female) underwent DECT and were divided into two groups: patients with reduced ejection fraction (HFrEF, LVEF＜40%) and patients with non-reduced ejection fraction (non-HFrEF, LVEF≥40%). 41 subjects (43±10 years, 17 female) who underwent DECT who were found to have no abnormalities were served as control groups. LIE was acquired 7 minutes after iodine administration of 0.9ml/kg of iopamidol and CCTA using a spectral CT. LIE images were reconstructed at 8mm slice thickness, 6mm slice gap to the short-axis plane of the left ventricular (LV) myocardium and then the basal, mid and apical slices were extracted. ROIs were manually drawn on LIE images using the AHA's 16-segmentation to calculate ECV. Differences of ECV between groups were compared and correlation between ECV and LVEF and NYHA classification were analyzed.
Results or Findings: The CT-ECV in patients with NIHF was significantly higher than that in HCs (34.63%±3.68 vs 28.03%±2.85, P<0.05 ). In patients with NIHF, there was an inverse correlation between CT-ECV and LVEF (r=-0.403, P<0.05), and the CT-ECV in HFrEF patients were higher than those in non-HFrEF patients (35.60%±4.15 vs 32.25%±1.68, P<0.05 ). The significant correlation between CT-ECV and NYHA classification could be observed (r=0.544, P<0.05 ). The mean radiation dose of LIE is 2.29 mSv±0.55.
Conclusion: ECV derived from Late Iodine enhancement can be used for risk stratification in patients with non-ischemic heart failure.
Limitations: Not applicable.
Ethics committee approval: Not applicable.
Funding for this study: National Natural Science Foundation of China (No.82060312). Yunnan Applied Basic Research Projects (No.2018E001(-039)) No.202101AT0702490

Author Block: J. Deng, D. Han, Z. Li, W. Gao, W. Chen; Kunming/CN
Purpose or Learning Objective: To validate the feasibility of myocardial extracellular volume fraction (ECV) derived from late iodine enhancement (LIE) via using dual-energy computed tomography, with the ECV from CMR T1 mapping as reference.
Methods or Background: 45 patients (45±14 years, 15 female) underwent both DECT and CMR. LIE was acquired 7 minutes after iodine administration of 0.9ml/kg of iopamidol and CCTA using the spectral CT. LIE images were reconstructed at 8mm slice thickness, 6mm slice gap to the short-axis plane of the left ventricular (LV) myocardium and then the basal, mid and apical slices were extracted. CMR T1 maps were obtained in short-axis at the basal, mid and apical slices of LV myocardium and consistent with the LIE images before and 10 minutes after intravenous administration of 0.1mmol/kg of gadolinium via using the MOLLI sequence. ROIs were manually drawn on the myocardium using the AHA's 16-segmentation. CT-ECV and CMR-ECV were double blindly calculated, respectively. Correlation, differences and agreement between the two groups and the reproducibility of CT-ECV were tested.
Results or Findings: Among the 45 patients, CT-ECV correlated with CMR-ECV (r= 0.926, P＜0.001) and there was no significant difference between the mean values of both (33.09%±4.21 vs 32.80%±4.89, P=0.293). Bland-Altman analysis showed CT-ECV was comparable to CMR-ECV with a small bias (95%CI: -3.97% to 3.38%, bias=-0.29%). The ICC for the inter- and intra-observer measurements were 0.963 and 0.976. Furthermore, the mean radiation dose of the LIE was 2.42 ± 0.49 mSv.
Conclusion: CT-ECV derived from LIE can serve as an excellent alternative to CMR-ECV in noninvasively quantifying diffused myocardial fibrosis and it has well reproducibility.
Limitations: Not applicable.
Ethics committee approval: Not applicable.
Funding for this study: National nature science foundation of China (No.82060312); Yunnan applied basic research projects. (No.2018E001(-039)); No.202101AT0702490