BACKGROUND: Dark-blood T2-weighted fast spin-echo (DB-FSE) is sensitive to motion, leading to signal dropout artifacts and ghosting artifacts in free-breathing pediatric cardiac imaging, which severely impairs its diagnostic quality. Here, we aimed to fulfill high-resolution motion-robust edema assessment during free-breathing by combining reverse double inversion recovery (RDIR) and single-shot DB-FSE based on artificial intelligence (AI)-assisted compressed sensing (ACS) reconstruction. METHODS: This prospective study included 20 healthy children and 47 pediatric patients. Three imaging techniques were compared: routine multi-shot DB-FSE based on double inversion recovery (MS-DIR), multi-shot DB-FSE based on RDIR (MS-RDIR), and single-shot DB-FSE based on RDIR (SS-RDIR) with ACS reconstruction. These methods were compared via quantitative metrics, including total acquisition time, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR), and qualitative metrics, including myocardial visibility, ghosting artifacts, and overall quality. RESULTS: In healthy children, the total acquisition time (seconds) of SS-RDIR (64.8±21.8) was significantly less than those of MS-DIR (222.5±69.3, P<
0.002) and MS-RDIR (234.0±64.1, P<
0.002). The SNR and CNR were comparable (P=0.094 for SNR and P=0.054 for CNR). Ghosting artifacts were significantly reduced in SS-RDIR (4.70±0.18) compared to MS-DIR (3.95±0.28, P<
0.002) and MS-RDIR (3.97±0.31, P<
0.002), whereas overall quality was improved in SS-RDIR (4.42±0.19) compared to MS-DIR (3.87±0.27, P=0.004) and MS-RDIR (3.95±0.34, P=0.010). In patients, SS-RDIR significantly reduced the total acquisition time compared to MS-DIR (62.1±24.0 CONCLUSIONS: SS-RDIR with ACS reconstruction offers substantially shorter scan time and superior image quality than traditional multi-shot techniques. This approach enhances clinical workflow and patient comfort, facilitating a broader application of DB-FSE in pediatric cardiac imaging.