Reproducibility and Repeatability of MR Fingerprinting Relaxometry in the Human Brain

Abstract

ontrast-weighted images are commonly acquired in MRI, where one tissue-related parameter usually dominates the contrast, such as T1 or T2 weighting. Relative contrast differences across one image indicate different underlying tissue parameters, but this requires several sequences with different contrast weighting for a final diagnosis. These weighted contrasts provide only qualitative information, which limits the ability of qualitative MRI to depict mostly morphologic abnormalities. Pathologic conditions that alter tissue characteristics on a global or diffuse scale may be missed (1). Instead of indirectly visualizing tissue characteristics by using weighted contrasts, quantitative MRI attempts to directly measure them. Thereby, quantitative MRI could facilitate identification of physiologic changes that do not manifest themselves in morphologic changes or could help detect diffuse tissue changes (eg, in liver [2] and cardiac fibrosis [3]) that remain undetected by using qualitative MRI. It can provide more specific information than does qualitative MRI for characterizing pathologic conditions, such as multiple sclerosis (4) or brain tumors (5). Furthermore, quantitative MRI can be used to assess treatment response (6) or can aid in cases where no side comparison can be performed, such as hippocampal sclerosis (7). With quantitative MRI, diseases can be detected before gross morphologic

Acceleration of 2D-MR fingerprinting by reducing the number of echoes with increased in-plane resolution: a volunteer study

“…In this study, MRF measurements with different numbers of echoes, and consequently scan lengths, were compared to examine inter-measurement differences and correlations of absolute T1 and T2 values using a relatively large number of subjects. The mean T1 and T2 values in this study were similar to those in a multi-center MRF study [10]. The values were strongly to very strongly correlated between MRF3k and MRF1.5k.…”

“…Recently, a multi-center study that assessed the repeatability and reproducibility of 2D MRF using FISP, which is the same as MRF3k but used a 20-channel head coil, was reported [10]. Intra-scanner repeatability half-widths of the confidence intervals for relative deviations, which are calculated as 1.96 times the CVs, were in the range of 2.0-3.1% for T1 and 3.1-7.9% for T2 in solid tissue compartments.…”

“…One MRF scan of a single slice using the established method acquires 3000 echoes and takes 42 s [8], resulting in a 14-min scan for a whole-brain acquisition covering 20 slices; however, a faster and higher-resolution acquisition is favorable for clinical application. Current MRF measurements of T1 and T2 have been reported to be very stable [9,10], and an MRF scan with a higher resolution in a shorter scan time is considered feasible.…”

“…1). MRF with 3000 echoes (MRF3k) [8,10] and MRF with 1500 echoes (MRF1.5k) were conducted. The latter scan parameter was set based on a study using an NIST/ISMRM system phantom (https :// www.nist.gov/progr ams-proje cts/quant itati ve-mri).…”

Intracranial Distribution of Intravenously Administered Gadolinium-based Contrast Agent over a Period of 24 Hours: Evaluation with 3D-real IR Imaging and MR Fingerprinting

“…9 MRF can also be used to evaluate the changes of T 1 and T 2 in brain parenchyma. [10][11][12][13] There is an advantage in that the dynamic range is larger using MRF than for 3D-real IR imaging alone.…”