Year: 2025
Type: article
Abstract: ABSTRACT Background T 2 ‐mapping has promise to evaluate kidney pathophysiology. Prior studies show a large variance in kidney T 2 , likely due to the differing acquisition sequences. Purpose To compare four T 2 ‐mapping sequences to investigate kidney T 2 . Study Type Phantom and prospective in vivo assessments. Participants ISMRM/NIST and QASPER phantoms; 8 healthy volunteers (4 female, 30 ± 8 years). Field Strength/Sequence 3 T, spin echo‐echo planar imaging (SE‐EPI), multi‐echo‐spin echo (ME‐SE), Gradient and Spin Echo (GraSE) vendor‐provided sequences, and custom T 2 ‐prepared EPI, Dual‐echo B 0 ‐mapping and DREAM B 1 ‐mapping. Assessment T 2 ‐mapping accuracy in the ISMRM/NIST phantom in the presence of B 0 frequency offset and B 1 + by scaling of flip angles, and in the QASPER phantom in the presence of diffusion by altering pump rate compared to being turned off. Participants underwent a single 45‐min exam to collect four T 2 ‐mapping sequences, B 0 and B 1 maps. In vivo T 2 values compared across sequences and the influence of B 0 and B 1 + was evaluated. Statistical Tests Shapiro–Wilk, Wilcoxon signed‐rank, Student's t ‐test, Coefficient of Variation, Pearson's correlation coefficient, linear mixed effect model. p < 0.05 considered statistically significant. Results SE‐EPI, ME‐SE, GraSE, and T 2 ‐prepared EPI had a mean absolute scaled error of 0.52, 0.52, 0.36, and 0.27 over the kidney T 2 range of the ISMRM/NIST phantom. GraSE was most robust to perturbations in B 0 /B 1 + . In the QASPER phantom, SE‐EPI was highly sensitive to diffusion leading to T 2 shortening (66%), while multi‐echo sequences had lower diffusion sensitivity ordered by shortest echo spacing (ME‐SE 81%, T 2 ‐prepared EPI 90%, GraSE 95% reduction in T 2 ). In vivo, SE‐EPI measured T 2 was significantly lower than multi‐echo sequences, and SE‐EPI and T 2 ‐preparation had a −0.52 ± 0.08 and −0.57 ± 0.06 ms/% dependence on B 1 + . Data Conclusion To reduce B 0 , B 1 + , and diffusion sensitivity for kidney T 2 ‐mapping, a multi‐echo sequence spanning echo times up to the kidney T 2 (~140 ms at 3 T) is recommended. Collecting data with different echo spacings can isolate the diffusion‐related T 2 component. Evidence Level 2. Technical Efficacy Stage 1.
DOI: 10.1002/jmri.70127
Authors: Alexander J. Daniel, Susan T. Francis
Language: English
Subfield: Radiology, Nuclear Medicine and Imaging
Field: Medicine
Domain: Health Sciences
Open Access status: hybrid
Estimated APC paid: $3,680
OpenAlex ID: W4414533210