The Feasibility of a Model-Based Iterative Reconstruction Technique Tuned for the Myocardium on Myocardial Computed Tomography Late Enhancement

Objectives This study evaluated the feasibility of a model-based iterative reconstruction technique (MBIR) tuned for the myocardium on myocardial computed tomography late enhancement (CT-LE). Methods Twenty-eight patients who underwent myocardial CT-LE and late gadolinium enhancement (LGE) magnetic resonance imaging (MRI) within 1 year were retrospectively enrolled. Myocardial CT-LE was performed using a 320-row CT with low tube voltage (80 kVp). Myocardial CT-LE images were scanned 7 min after CT angiography (CTA) without additional contrast medium. All myocardial CT-LE images were reconstructed with hybrid iterative reconstruction (HIR), conventional MBIR (MBIRcardiac), and new MBIR tuned for the myocardium (MBIRₘyo). Qualitative (5-grade scale) scores and quantitative parameters (signal-to-noise ratio SNR and contrast-to-noise ratio CNR) were assessed as image quality. The sensitivity, specificity, and accuracy of myocardial CT-LE were evaluated at the segment level using an American Heart Association (AHA) 16-segment model, with LGE-MRI as a reference standard. These results were compared among the different CT image reconstructions. Results In 28 patients with 448 segments, 160 segments were diagnosed with positive by LGE-MRI. In the qualitative assessment of myocardial CT-LE, the mean image quality scores were 2. 9 ± 1. 2 for HIR, 3. 0 ± 1. 1 for MBIRcardiac, and 4. 0 ± 1. 0 for MBIRₘyo. MBIRₘyo showed a significantly higher score than HIR (P < 0. 001) and MBIRcardiac (P = 0. 018). In the quantitative image quality assessment of myocardial CT-LE, the median image SNR was 10. 3 (9. 1–11. 1) for HIR, 10. 8 (9. 8–12. 1) for MBIRcardiac, and 16. 8 (15. 7–18. 4) for MBIRₘyo. The median image CNR was 3. 7 (3. 0–4. 6) for HIR, 3. 8 (3. 2–5. 1) for MBIRcardiac, and 6. 4 (5. 0–7. 7) for MBIRₘyo. MBIRₘyo significantly improved the SNR and CNR of CT-LE compared to HIR and MBIRcardiac (P < 0. 001). The sensitivity, specificity, and accuracy for the detection of myocardial CT-LE were 70%, 92%, and 84% for HIR; 71%, 92%, and 85% for MBIRcardiac; and 84%, 92%, and 89% for MBIRₘyo, respectively. MBIRₘyo showed significantly higher image quality, sensitivity, and accuracy than the others (P < 0. 05). Conclusions MBIR tuned for myocardium improved image quality and diagnostic performance for myocardial CT-LE assessment.