{"doi":"10.1002/mrm.70508","title":"Fast Localized Calibration for Spatial‐Spectral Excitation Without Fly‐Back Gradients","abstract":"PURPOSE: Standard spatial-spectral excitation pulses apply a fly-back gradient between sub-pulses, limiting, for example, how thin the slices can be (> 4 mm). Without fly-back gradients, slices can be as thin as 1.7 mm but require a phase calibration for the sub-pulses with inverted gradients due to system imperfections. Here we propose and test a fast (< 1 s), localized pre-scan enabling thin-slice frequency-selective excitation. METHODS: The calibration pre-scan determines the correction phase between even and odd sub-pulses by measuring the phase difference of two FIDs excited with either the last or second-to-last RF sub-pulse of the spatial-spectral pulse. Non-localized and localized versions of the calibration pre-scan are tested and validated for water-only excitation in phantoms and the human heart. As an example, breath-held coronary MR angiography is performed with a spiral multi-slice sequence employing the proposed pulses with a slice thickness of 1.7 mm. RESULTS: The proposed calibration pre-scan takes 11.1 ms per slice, whether it is localized or not. Localized calibration phases are validated with an image-based calibration map. Slice profiles are visualized for pulses with different time-bandwidth products. Fat is suppressed to below 20% and 25% of the surrounding water signal in both phantoms and the human heart, respectively. High-quality coronary angiograms are demonstrated in all test subjects. CONCLUSION: Spatial-spectral pulses without fly-back gradients can be calibrated quickly (up to 90 slices in 1 s), enabling thinner slices, higher excitation angles, or pulses with sharper slice profiles using waveforms with higher time-bandwidth products.","journal":"Magnetic Resonance in Medicine","year":2024,"id":502074,"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":0,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9532,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2024-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":1351572,"name":"Robert Weiss","orcid":"0000-0002-7168-5401","position":1,"is_corresponding":false},{"id":497800,"name":"Allison G. Hays","orcid":"0000-0003-2138-1589","position":3,"is_corresponding":false},{"id":271391,"name":"Michael Schär","orcid":"0000-0002-7044-9941","position":0,"is_corresponding":true}],"reference_count":22,"raw_metadata":null,"created_at":"2026-07-19T02:10:19.647285Z","pmid":"42424098","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":[]}