{"doi":"10.3389/fphy.2022.1033767","title":"Correction of the post-irradiation T1 relaxation effect for chemical exchange-sensitive MRI: A phantom study","abstract":"Purpose: In many pulse sequences of chemical exchange-sensitive MRI including multi-slice chemical exchange saturation transfer (CEST) or chemical exchange sensitive spin-lock (CESL), there is a finite time delay between the irradiation preparation and the imaging acquisition, during which the T 1 -relaxation reduces the chemical exchange contrast and affects the accuracy for volumetric imaging. We propose a simple post-acquisition method to correct this contamination. Methods: A simple formula was derived to evaluate the cross-slice T 1 -relaxation contamination in multi-slice echo-planar imaging (EPI) after the irradiation preparation. CEST and CESL experiments were performed on phantoms to examine the accuracy of this approach. Results: Theoretical derivation showed that the cross-slice T 1 -relaxation contamination in multi-slice EPI imaging can be corrected by the signals of each slice at a parameter that suppresses the signal, e.g., at the water frequency for CEST, or with very long spin-lock pulse for CESL. This formula was confirmed by the results of phantom experiments, for both long and short irradiation durations with and without a steady-state, respectively. To minimize the effect of B 0 inhomogeneity in the CEST experiment, a more accurate measurement of the signal at water frequency can be achieved with a higher pulse power and shorter duration. Conclusion: We proposed and validated a simple approach to correct the cross-slice T 1 -relaxation effect, which can be applied to volumetric CEST and CESL studies acquired by multi-slice EPI, or other imaging modalities with similar T 1 -relaxation contamination.","journal":"Frontiers in Physics","year":2022,"id":312469,"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":0.9601,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2022-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":841951,"name":"Tao Jin","orcid":"0000-0003-2912-3517","position":1,"is_corresponding":false},{"id":861565,"name":"Julius Juhyun Chung","orcid":"0000-0002-1513-5181","position":0,"is_corresponding":true}],"reference_count":39,"raw_metadata":null,"created_at":"2026-07-19T00:33:36.072096Z","pmid":null,"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":[]}