Truncation and exponential + constant decay models for calculating myocardial R2* values yielded similar results with strong agreement (R-squared >0.997 and coefficient of variation of 3% to 4%).
Observational
Yes
Does the choice of decay model (truncation vs Exp-C) affect myocardial R2* values in cardiac MRI?
Cardiac R2* values are independent of the signal model used for calculation over clinically relevant ranges, allowing confident comparison of results among centers using disparate approaches.
Effect estimate: R-squared >0.997
PURPOSE: To determine whether systematic differences were present between myocardial R2* values obtained with two different decay models: truncation and exponential + constant (Exp-C). METHODS: Single-center cohorts were used to compare black and bright blood sequences separately, and a multicenter cohort of mixed bright and black blood studies was used to assess the generalizability. Truncated exponential estimates were calculated with CMRtools, which uses a single region of interest (ROI) method. Exp-C estimates were calculated using a pixelwise approach. RESULTS: No differences could be distinguished based upon whether a white or black blood sequence was examined. The two fitting algorithms yielded similar R2* values, with R-squared values exceeding 0.997 and a coefficient of variation of 3% to 4%. Results using the pixelwise method yielded a small systematic bias (∼3%) that became apparent in patients with severe iron deposition. This disparity disappeared when Exp-C fitting was used on a single ROI, suggesting that the use of pixelwise mapping was responsible for the bias. In the multicenter cohort, the strong agreement between the two fitting approaches was reconfirmed. CONCLUSION: Cardiac R2* values are independent of the signal model used for its calculation over clinically relevant ranges. Clinicians can compare results among centers using these disparate approaches with confidence.
Meloni et al. (Tue,) conducted a observational in Myocardial iron deposition. Truncation decay model vs. Exponential + constant (Exp-C) decay model was evaluated on Systematic differences between myocardial R2* values (R-squared >0.997). Truncation and exponential + constant decay models for calculating myocardial R2* values yielded similar results with strong agreement (R-squared >0.997 and coefficient of variation of 3% to 4%).