Abstract
Abstract
Objective
To determine the variability, and preferred values, for normal liver longitudinal water proton relaxation rate R1 in the published literature.
Methods
Values of mean R1 and between-subject variance were obtained from literature searching. Weighted means were fitted to a heuristic and to a model.
Results
After exclusions, 116 publications (143 studies) remained, representing apparently normal liver in 3392 humans, 99 mice and 249 rats. Seventeen field strengths were included between 0.04 T and 9.4 T. Older studies tended to report higher between-subject coefficients of variation (CoV), but for studies published since 1992, the median between-subject CoV was 7.4%, and in half of those studies, measured R1 deviated from model by 8.0% or less.
Discussion
The within-study between-subject CoV incorporates repeatability error and true between-subject variation. Between-study variation also incorporates between-population variation, together with bias from interactions between methodology and physiology. While quantitative relaxometry ultimately requires validation with phantoms and analysis of propagation of errors, this survey allows investigators to compare their own R1 and variability values with the range of existing literature.
Funder
Innovative Medicines Initiatives 2 Joint Undertaking
Publisher
Springer Science and Business Media LLC
Subject
Radiology, Nuclear Medicine and imaging,Radiological and Ultrasound Technology,Biophysics
Cited by
3 articles.
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