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Updated: Aug 1, 2025
In Vivo Quantitative Assessment of Myocardial Structure, Function, Perfusion and Viability Using Cardiac Micro-computed Tomography
Published on: February 16, 2016
Cardiac MRI-derived Extracellular Volume Fraction versus Myocardium-to-Lumen R1 Ratio at Postcontrast T1 Mapping for
Masafumi Kidoh1, Seitaro Oda1, Seiji Takashio1
1Department of Diagnostic Radiology (M.K., S.O., H.H., F.Y., T.N., Y.N., T.H.), Department of Cardiovascular Medicine (S.T., K.T.), Department of Hematology, Rheumatology, and Infectious Disease (Y.K., M.M.), and Department of Neurology (M.U.), Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Chuo-ku, Kumamoto 860-8556, Japan; and Department of Central Radiology, Kumamoto University Hospital, Kumamoto, Japan (K.M., T.E., S.S.).
Purpose:
To evaluate the diagnostic performance of myocardium-to-lumen R1 (1/T1) ratio on postcontrast T1 maps for the detection of cardiac amyloidosis in a large patient sample.
Materials And Methods:
This retrospective study included consecutive patients who underwent MRI-derived extracellular volume fraction (MRI ECV) analysis between March 2017 and July 2021 because of known or suspected heart failure or cardiomyopathy. Pre- and postcontrast T1 maps were generated using the modified Look-Locker inversion recovery sequence. Diagnostic performances of MRI ECV and myocardium-to-lumen R1 ratio on postcontrast T1 maps (a simplified index not requiring a native T1 map and hematocrit level data) for detecting cardiac amyloidosis were evaluated using the area under the receiver operating characteristic curve (AUC), sensitivity, and specificity.
Results:
Of 352 patients (mean age, 63 years ± 16 [SD]; 235 men), 136 had cardiac amyloidosis. MRI ECV showed 89.0% (121 of 136; 95% CI: 82%, 94%) sensitivity and 98.6% (213 of 216; 95% CI: 96%, 100%) specificity for helping detect cardiac amyloidosis (cutoff value of 40% [AUC, 0.99 {95% CI: 0.97, 1.00}; P < .001]). Postcontrast myocardium-to-lumen R1 ratio showed 92.6% (126 of 136; 95% CI: 89%, 96%) sensitivity and 93.1% (201 of 216; 95% CI: 89%, 96%) specificity (cutoff value of 0.84 [AUC, 0.98 {95% CI: 0.95, 0.99}; P < .001]). There was no evidence of a difference in AUCs for each parameter (P = .10).
Conclusion:
Postcontrast myocardium-to-lumen R1 ratio showed excellent diagnostic performance comparable to that of MRI ECV in the detection of cardiac amyloidosis.Keywords: MR Imaging, Cardiac, Heart, Cardiomyopathies Supplemental material is available for this article. © RSNA, 2023.
Insights
The postcontrast myocardium-to-lumen R1 ratio effectively detects cardiac amyloidosis, offering diagnostic performance comparable to MRI ECV. This simplified index aids in diagnosing this heart condition.
Area of Science:
- Cardiovascular Imaging
- Radiology
- Medical Diagnostics
Background:
- Cardiac amyloidosis is a progressive disease affecting heart function.
- Accurate diagnosis is crucial for timely intervention and management.
- Magnetic Resonance Imaging (MRI) plays a vital role in evaluating cardiac conditions.
Purpose of the Study:
- To assess the diagnostic accuracy of the myocardium-to-lumen R1 ratio on postcontrast T1 maps for detecting cardiac amyloidosis.
- To compare the performance of this simplified R1 ratio with the established MRI-derived extracellular volume fraction (MRI ECV) method.
Main Methods:
- Retrospective analysis of 352 patients undergoing MRI ECV analysis for suspected heart failure or cardiomyopathy.
- Generation of pre- and postcontrast T1 maps using the modified Look-Locker inversion recovery sequence.
- Evaluation of diagnostic performance using Area Under the Curve (AUC), sensitivity, and specificity for both MRI ECV and the myocardium-to-lumen R1 ratio.
Main Results:
- Cardiac amyloidosis was present in 136 of 352 patients.
- MRI ECV demonstrated 89.0% sensitivity and 98.6% specificity (AUC, 0.99).
- The myocardium-to-lumen R1 ratio showed 92.6% sensitivity and 93.1% specificity (AUC, 0.98), with no significant difference in AUCs compared to MRI ECV (P = .10).
Conclusions:
- The postcontrast myocardium-to-lumen R1 ratio is a highly effective and comparable alternative to MRI ECV for diagnosing cardiac amyloidosis.
- This simplified R1 ratio offers excellent diagnostic performance without requiring native T1 maps or hematocrit data.
- The findings support the utility of the R1 ratio as a valuable tool in cardiac amyloidosis detection via MRI.
