LiverT₁ρMRI measurement in healthy human subjects at 3 T: a preliminary study with a two-dimensional fast-field echo sequence

Abstract

Objectives: The aim of this study was to explore the technical feasibility of T 1 r MRI for the liver, and to determine the normal range of liver T 1 r in healthy subjects at clinical 3 T. Methods: There were 15 healthy volunteers. Three representative axial slices were selected to cut through the upper, middle and lower liver. A rotary echo spin-lock pulse was implemented in a two-dimensional fast-field echo sequence. Spin-lock frequency was 500 Hz, and the spin-lock times of 1, 10, 20, 30, 40 and 50 ms were used for T 1 r mapping. The images were acquired slice by slice during breath-holding. Regions of interest (ROIs; n55) were manually placed on each slice of the liver parenchyma region, excluding artefacts and vessels. The mean value of these ROIs (n515) was regarded as the liver T 1 r value for the subject. Six subjects were scanned once at fasting status; six subjects were scanned once 2 h post meal; three subjects were scanned twice at fasting status; and seven subjects were scanned twice 2 h post meal. Results: When two readers measured the same 10 data sets, the interreader reproducibility (ICC: intraclass correlation coefficient) was 0.955. With the 10 subjects scanned twice, the ICC for scan-rescan reproducibility was 0.764. There was no significant difference for the liver T 1 r value at the fasting status (43.08¡1.41 ms) and post-meal status (42.97¡2.38 ms, p50.867). Pooling together all the 32 scans in this study, the normal liver T 1 r value ranged from 38.6 to 48.3 ms (mean 43.0 ms, median 42.6 ms). Conclusion: It is feasible to obtain consistent liver T 1 r measurement for human subjects at 3 T.

MR T1ρ as an imaging biomarker for monitoring liver injury progression and regression: an experimental study in rats with carbon tetrachloride intoxication

“…Liver signal intensity decreases upon the withdrawal of CCl 4 insult, and returns to the baseline value at week 4 post CCl 4 withdrawal out healthy volunteer liver T1ρ MR measurements. We found that when two readers measured the same ten volunteers' MR images, the inter-reader reproducibility (ICC) was 0.955; and with the ten subjects imaged twice, the ICC for reproducibility of repeat MR examinations was 0.764, suggesting the clinical applicability of liver MR T1ρ technique [41].…”

Chemical exchange saturation transfer (CEST) MR technique for in-vivo liver imaging at 3.0 tesla

“…A number of MR imaging techniques have been investigated to assess early liver parenchyma fibrosis, including T 1 rho imaging [27-31], tagged MRI assessing liver strain [32], MR elastography [33, 34] and intravoxel incoherent motion (IVIM) technique [35, 36]. Our current study for the first time demonstrated the feasibility and evaluated the reproducibility of CEST imaging of in-vivo liver at the clinical field strength of 3T in both rats and human.…”

Black blood T1rho MR imaging may diagnose early stage liver fibrosis: a proof-of-principle study with rat biliary duct ligation model

“…A total of approximately 15 ROIs were obtained each liver, and the mean value of these 15 ROIs was regarded as the value of the liver T1ρ. The inter-and intra-reader reproducibility for ROI placement has been shown to be excellent in past studies (7,8) [more details of the ROI placement are shown in supplement document of reference (7)]. …”

“…Despite the biophysical mechanism has not been fully illuminated, recently Wang et al and Zhao et al described the usefulness of T1ρ MR imaging for assessment in rat liver fibrosis models, with the increase of T1ρ value correlated severity of fibrosis. Studies in human subjects, both in healthy volunteers and liver fibrosis patients, soon followed (7)(8)(9)(10)(11)(12)(13)(14)(15). In a group of 25 healthy volunteers and 35 cirrhosis patients, Allkemper et al (11) reported that T1ρ values did not correlate with necroinflammatory activity, degree of steatosis or presence of iron load, but it was significantly associated with the ChildPugh staging of the patients.…”