{"doi":"10.1002/mrm.70196","title":"Overlap‐Kernel <scp>EPI</scp> : Estimating <scp>MRI</scp> Shot‐to‐Shot Phase Variations by Shifted‐Kernel Extraction From Overlap Regions at Arbitrary k‐Space Locations","abstract":"PURPOSE: In multi-shot EPI, shot-dependent phase fluctuations can introduce ghost artifacts, undermining advantages for enhancing resolution or reducing distortion, particularly in diffusion scans. Here, a novel self-navigation strategy based on shift-invariant kernel extraction is proposed, enabling robust estimation of phase inconsistencies from overlap bands at any k-space locations. It is inspired by RF sensitivity auto-calibration in parallel imaging, and extends traditional self-navigation trajectories beyond oversampled k-space center. THEORY AND METHODS: Our shot-to-shot correction method only requires shot-to-shot sampling trajectories to slightly overlap at arbitrary k-space locations. Such k-space overlaps can be defined as shot-dependent auto-calibrating-signal regions, where a GRAPPA/ESPIRiT-type operation can be applied to explicitly extract shot-to-shot signal variation maps in one step. This inherits GRAPPA/ESPIRiT's robustness, and offers much greater flexibility in designing self-navigated multi-shot sequences. RESULTS: maps. Given sufficient SNR, self-navigation EPI can reach identical/better reconstruction quality compared to navigator corrections, applicable to various trajectories. Additionally, it is particularly suitable for the two-shot and four-shot mosaic EPI, where stronger shot-dependent eddy currents can also be removed, and the self-navigated ACS has higher SNR than the refocused navigator echoes. CONCLUSION: This paper rigorously analyzes subspace algorithms for phase-stabilized multi-shot MRI, significantly broadens the self-navigation concept, and provides a more complete picture of the connections between signal fluctuations calibration in EPI and RF sensitivity calibration in parallel imaging.","journal":"Magnetic Resonance in Medicine","year":2025,"id":537558,"datarank":0.0,"base_score":0.0,"endowment":0.0,"self_citation_contribution":0.0,"citation_network_contribution":0.0,"self_endowment_contribution":0.0,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":1,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9514,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2025-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":478981,"name":"Martin Uecker","orcid":"0000-0002-8850-809X","position":1,"is_corresponding":false},{"id":516415,"name":"Maxim Zaitsev","orcid":"0000-0001-7530-1228","position":2,"is_corresponding":false},{"id":384838,"name":"Klaus Scheffler","orcid":"0000-0001-6316-8773","position":3,"is_corresponding":false},{"id":1423360,"name":"Rui Tian","orcid":"0000-0003-0587-1406","position":0,"is_corresponding":true}],"reference_count":75,"raw_metadata":null,"created_at":"2026-07-19T02:52:12.997494Z","pmid":"41399144","pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}