Publications
Take a look

by Sirisha Tadimalla PhD, Daniel J. Wilson PhD, David Shelley BSc, Gavin Bainbridge BSc, Margaret Saysell BSc, Iosif A. Mendichovszky MD, Martin J. Graves PhD, J. Ashley Guthrie MB, John C. Waterton PhD, Geoffrey J.M. Parker PhD, Steven P. Sourbron PhD

JMRI 2022, 56(4), 1042-1052. doi: 10.1002/jmri.28127

Abstract

Background
Three-dimensional variable flip angle (VFA) methods are commonly used for T1 mapping of the liver, but there is no data on the accuracy, repeatability, and reproducibility of this technique in this organ in a multivendor setting.

Purpose
To measure bias, repeatability, and reproducibility of VFA T1 mapping in the liver.

Study Type
Prospective observational.

Population
Eight healthy volunteers, four women, with no known liver disease.

Field Strength/Sequence
1.5-T and 3.0-T; three-dimensional steady-state spoiled gradient echo with VFAs; Look-Locker.

Assessment
Traveling volunteers were scanned twice each (30 minutes to 3 months apart) on six MRI scanners from three vendors (GE Healthcare, Philips Medical Systems, and Siemens Healthineers) at two field strengths. The maximum period between the first and last scans among all volunteers was 9 months. Volunteers were instructed to abstain from alcohol intake for at least 72 hours prior to each scan and avoid high cholesterol foods on the day of the scan.

Statistical Tests
Repeated measures ANOVA, Student t-test, Levene's test of variances, and 95% significance level. The percent error relative to literature liver T1 in healthy volunteers was used to assess bias. The relative error (RE) due to intrascanner and interscanner variation in T1 measurements was used to assess repeatability and reproducibility.

Results
The 95% confidence interval (CI) on the mean bias and mean repeatability RE of VFA T1 in the healthy liver was 34 ± 6% and 10 ± 3%, respectively. The 95% CI on the mean reproducibility RE at 1.5 T and 3.0 T was 29 ± 7% and 25 ± 4%, respectively.

Data Conclusion
Bias, repeatability, and reproducibility of VFA T1 mapping in the liver in a multivendor setting are similar to those reported for breast, prostate, and brain.