Detection of liver fibrosis with magnetic cross‐relaxation

Abstract

The utility of MRI using magnetization transfer (MT) enhanced pulse sequences to diagnose hepatic cirrhosis in a rat model was investigated. Hepatic T1 was measured with and without MT off-resonance RF pulses in 17 treated and six control rats. The livers were evaluated histologically, and the hydroxyproline content quantitatively measured. We did not find a statistically significant linear correlation between the MR relaxation times and the degree of tissue injury. However, the MR measurements performed with MT were superior to those without differentiating the treated and control groups. Specifically, the T1 times were 695 +/- 76 ms for the treated group, versus 748 +/- 61 ms in the controls; P = 0.095. The T1sat times were also lower in the treated group, with statistical significance: 367 +/- 51 ms versus 421 +/- 38 ms, P = 0.016. Finally, the change in the relaxation rates (the inverse of the relaxation times) with and without saturation were 1.31 +/- 0.22 s-1 (treated group) versus 1.05 +/- 0.12 s-1 (controls), which differed significantly, P = 0.001.

Diagnosis and Measurement of Liver Fibrosis by MRI in Bile Duct Ligated Rats

“…This emphasizes the difficulty of finding an animal model of pure fibrosis, with no significant associated lesions. To our knowledge, only one study has demonstrated the expected decrease in rT in an animal model of fibrosis [4]. In this study, the model was unusual since CCl 4 administration was longer (14 weeks) than usual (6 to 8 weeks).…”

“…Moreover, the area of fibrosis did not vary significantly among the three liver fragments from different lobes. Several studies have tried to visualize hepatic fibrosis using the modification of the MRI parameters [2,3,[4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. But only two [7,8] have shown a significant correlation between these parameters and the degree of hepatic fibrosis.…”

“…Moreover, as in liver iron quantification [1], it has been suggested that MRI might be used to quantify liver fibrosis [2,3]. However, previous studies on the measurement of liver fibrosis by MRI [2,3,[4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] have shown an increase in relaxation times (rTs), whereas a decrease in these parameters was expected.…”

Induced Hepatic Fibrosis in Rats: Hepatic Steatosis, Macromolecule Content, Perfusion Parameters, and Their Correlations—Preliminary MR Imaging in Rats

“…The initial decrease of MTR until 6 -8 weeks of CCl 4 treatment and its rise back to baseline values suggest that the MTR variations observed are not specific to the extracellular matrix components. Aisen et al (9) reported a lack of sensitivity of magnetization transfer contrast to the amount of fibrosis. In another animal study (11), end-stage Niemann-Pick type C mice had more than 100% (2.4 vs 1.1) higher hydroxyproline content but only 17% higher MTR than control animals.…”

Evaluation of liver diseases via MTC and contrast agent

“…The only report in the literature on MTC study of cirrhosis and fibrosis is on rats (31). In theory, cirrhosis should have a strong MT effect due to the abundance of collagen.…”