Objective <p>Cardiac T2-weighted short-tau inversion recovery (T2w-STIR) is highly susceptible to myocardial motion, and acquisition at inappropriate cardiac phases can cause myocardial signal loss and inhomogeneity. This study investigated whether cardiac phase selection based on motion-sensitive (MoSe) cine imaging improves T2w-STIR image quality compared with conventional ECG-synchronized acquisition at the longest trigger delay corresponding to end-diastole.</p> Materials and methods <p>Twelve healthy volunteers underwent 1.5T cardiac MRI. MoSe cine imaging with ECG and peripheral pulse unit (PPU) synchronization was used to visually identify phases with minimal myocardial motion. Short-axis T2w-STIR images were acquired at Conv[ECG-l] (longest ECG trigger delay at end-diastole), MoSe[ECG-S] (MoSe-determined systolic phase with ECG), and MoSe[PPU-D] (MoSe-determined diastolic phase with PPU). Quantitative assessments were myocardium-to-spleen ratio (MSR) and inter- and intra-slice MSR coefficient of variation (CV). Overall image quality was scored on a 4-point scale.</p> Results <p>MoSe[PPU-D] yielded higher MSR and lower inter- and intra-slice CVs than Conv[ECG-l] (p &lt; 0.05), and higher MSR and lower intra-slice CV than MoSe[ECG-S] (p &lt; 0.05). Qualitative scores were higher for MoSe[PPU-D] than for Conv[ECG-l] and MoSe[ECG-S] (p &lt; 0.05).</p> Conclusion <p>Cardiac T2w-STIR images acquired at the MoSe-identified optimal diastolic phase with PPU synchronization provide superior image quality compared with conventional ECG-synchronized approach.</p>