Experimental Protocols for MRI Mapping of Renal T1

Abstract

The water proton longitudinal relaxation time, T1, is a common and useful MR parameter in nephrology research. Here we provide three step-by-step T1-mapping protocols suitable for different types of nephrology research. Firstly, we provide a single-slice 2D saturation recovery protocol suitable for studies of global pathology, where whole-kidney coverage is unnecessary. Secondly, we provide an inversion recovery type imaging protocol that may be optimized for specific kidney disease applications. Finally, we also provide imaging protocol for small animal kidney imaging in a clinical scanner.This chapter is based upon work from the COST Action PARENCHIMA, a community-driven network funded by the European Cooperation in Science and Technology (COST) program of the European Union, which aims to improve the reproducibility and standardization of renal MRI biomarkers. This analysis protocol chapter is complemented by two separate chapters describing the basic concept and experimental procedure.

Multiparametric MRI of Solid Renal Masses: Principles and Applications of Advanced Quantitative and Functional Methods for Tumor Diagnosis and Characterization

“…The reference standard inversion recovery (IR) method is highly accurate but has long acquisition times that make it impractical for clinical use 52 . Other methods have been developed for more rapid T 1 measurement, including the Look‐Locker sequence and variants such as the modified Look‐Locker inversion recovery (MOLLI), and the variable flip angle (VFA) technique 53,54 . Each of these techniques has different strengths and limitations.…”

“…52 Other methods have been developed for more rapid T 1 measurement, including the Look-Locker sequence and variants such as the modified Look-Locker inversion recovery (MOLLI), and the variable flip angle (VFA) technique. 53,54 Each of these techniques has different strengths and limitations. For example, MOLLI, developed for use in cardiac T 1 mapping, is widely available on commercial scanners and has fast acquisition times, but can be limited with respect to spatial resolution.…”

“…53 Meanwhile, the VFA approach allows for both twodimensional (2D) and three-dimensional (3D) acquisition and is useful for DCE-MRI 52 but is sensitive to B 1 + field inhomogeneity, which can result in poor precision for the absolute assessment of native T 1. 54 In addition, contrastenhanced (CE-)T 1 mapping allows for the calculation of extracellular volume fraction (ECV), which quantifies the size of the extracellular space as a percentage. 49 RESULTS IN HUMAN SUBJECTS.…”

“…It is also recommended that imaging is performed during fasting to minimize motion from bowel gas. 54 CONCLUSION. In summary, T 1 mapping is a quantitative MRI technique that can provide a quantitative assessment of tissue microstructure and is performed either without or with GBCA.…”

“…The Look‐Locker IR technique, commonly used in cardiac and abdominal applications, systematically under‐estimates T 1 , although it has been shown to have good test–retest repeatability 64 . The commonly used VFA technique is sensitive to B 1 + field inhomogeneity which can result in poor precision for the absolute assessment of native T 1 measurement, 54 and in poor repeatability 64 . B 1 correction may be employed as strategy to address this challenge.…”