{"doi":"10.1002/nbm.5324","title":"Quantification of NAD<sup>+</sup><i>T</i><sub>1</sub> and <i>T</i><sub>2</sub> Relaxation Times Using Downfield <sup>1</sup>H MRS at 7 T in Human Brain In Vivo","abstract":"ABSTRACT The purpose of this study was to measure T 1 and T 2 relaxation times of NAD + proton resonances in the downfield 1 H MRS spectrum in human brain at 7 T in vivo and to assess the propagation of relaxation time uncertainty in NAD + quantification. Downfield spectra from eight healthy volunteers were acquired at multiple echo times to measure T 2 relaxation times, and saturation recovery data were acquired to measure T 1 relaxation times. The downfield acquisition used a spectrally selective 90° sinc pulse for excitation centered at 9.1 ppm with a bandwidth of 2 ppm, followed by a 180° spatially selective Shinnar–Le Roux refocusing pulse for localization. Uncertainty propagation analysis on metabolite quantification was performed analytically and with Monte Carlo simulation. [NAD + ] was quantified in five participants. The mean ± standard deviation of T 1 relaxation times of the H2, H6, and H4 NAD + protons were 205.6 ± 25.7, 211.6 ± 33.5, and 237.3 ± 42.4 ms, respectively. The mean ± standard deviation of T 2 relaxation times of the H2, H6, and H4 protons were 33.6 ± 7.4, 29.1 ± 4.7, and 42.3 ± 11.6 ms, respectively. The relative uncertainty in NAD + concentration due to relaxation time uncertainty was 8.4%–11.4%, and measured brain [NAD + ] ( N = 5) was 0.324 ± 0.050 mM. Using downfield spectrally selective spectroscopy with single‐slice localization, we found T 1 and T 2 relaxation times averaged across all NAD + resonances to be approximately 218 and 35 ms, respectively, in the human brain in vivo at 7 T.","journal":"NMR in Biomedicine","year":2025,"id":531854,"datarank":0.20794415416798362,"base_score":1.3862943611198906,"endowment":1.3862943611198906,"self_citation_contribution":0.20794415416798362,"citation_network_contribution":0.0,"self_endowment_contribution":0.20794415416798362,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":3,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9463,"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":891953,"name":"Neil Wilson","orcid":"0009-0002-7766-2929","position":1,"is_corresponding":false},{"id":1282386,"name":"Mark A. Elliott","orcid":"0000-0003-2560-8760","position":2,"is_corresponding":false},{"id":469610,"name":"Ravi Prakash Reddy Nanga","orcid":"0000-0002-3644-5656","position":3,"is_corresponding":false},{"id":227867,"name":"Ravinder Reddy","orcid":"0000-0003-4580-2392","position":4,"is_corresponding":false},{"id":329911,"name":"Walter R. Witschey","orcid":"0000-0003-1669-2120","position":5,"is_corresponding":false},{"id":686831,"name":"Sophia Swago","orcid":"0000-0001-8334-4746","position":0,"is_corresponding":true}],"reference_count":60,"raw_metadata":{"citation_network_status":"fetched"},"created_at":"2026-07-19T02:51:18.928280Z","pmid":"39844458","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":[]}