{"doi":"10.1002/mrm.30413","title":"In vivo simultaneous proton resonance frequency shift thermometry and single reference variable flip angle <scp>T<sub>1</sub></scp> measurements","abstract":"Abstract Purpose The single reference variable flip angle sequence with a multi‐echo stack of stars acquisition (SR‐VFA‐SoS) simultaneously measures temperature change using proton resonance frequency (PRF) shift and T 1 ‐based thermometry methods. This work evaluates SR‐VFA‐SoS thermometry in MR‐guided focused ultrasound in an in vivo rabbit model. Methods Simultaneous PRF shift thermometry and T 1 ‐based thermometry were obtained in a New Zealand white rabbit model ( n = 7) during MR‐guided focused ultrasound surgery using the SR‐VFA‐SoS sequence at 3 T. Distinct locations in muscle ( n = 16), fat ( n = 12), or the interface of both tissues ( n = 23) were heated. The T 1 ‐temperature coefficient of fat was determined using least‐squares fitting of inversion recovery‐based T 1 maps of untreated fat harvested from the animal and was applied to the in vivo measured heat‐induced T 1 changes to create temperature maps. Results Using k‐space weighted image contrast reconstruction, temporal resolution of 1.71 s was achieved for simultaneous thermometry at 1.5 × 1.5 × 2 mm voxel resolution. PRF shift thermometry was not sensitive to heating in fat. T 1 changes were observed in fat at the ultrasound focus. The mean T 1 ‐temperature coefficient for fat was determined to be 1.9%/°C ± 0.2%/°C. Precision was 0.76°C ± 0.18°C for PRF shift thermometry in muscle and 1.93°C ± 0.60°C for T 1 ‐based thermometry in fat. Sonications in muscle showed an increase in T 1 of 2.4%/°C ± 0.9%/°C. Conclusion The SR‐VFA‐SoS sequence was shown to simultaneously measure temperature change using PRF shift and T 1 ‐based methods in an in vivo model, providing thermometry for both aqueous and fat tissues.","journal":"Magnetic Resonance in Medicine","year":2025,"id":522588,"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":4,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9579,"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":1394753,"name":"Michael Malmberg","orcid":null,"position":1,"is_corresponding":false},{"id":388327,"name":"Henrik Odéen","orcid":"0000-0003-2055-9795","position":2,"is_corresponding":false},{"id":389948,"name":"Sara Johnson","orcid":"0000-0001-8796-1549","position":3,"is_corresponding":false},{"id":1241452,"name":"Michelle A. Kline","orcid":"0000-0002-1998-6928","position":4,"is_corresponding":false},{"id":466168,"name":"Robb Merrill","orcid":"0000-0002-7982-2028","position":5,"is_corresponding":false},{"id":1394754,"name":"Rock Hadley","orcid":null,"position":6,"is_corresponding":false},{"id":388330,"name":"Dennis L. Parker","orcid":"0000-0003-2557-8952","position":7,"is_corresponding":false},{"id":388329,"name":"Allison Payne","orcid":"0000-0002-7724-5001","position":8,"is_corresponding":false},{"id":1241451,"name":"Nicholas Richards","orcid":"0009-0008-4832-1651","position":0,"is_corresponding":true}],"reference_count":84,"raw_metadata":null,"created_at":"2026-07-19T02:49:54.058858Z","pmid":"39831523","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":[]}