Z Qiao

Liver fibrosis: an intravoxel incoherent motion (IVIM) study.

To characterize longitudinal changes in molecular water diffusion, blood microcirculation, and their contributions to the apparent diffusion changes using intravoxel incoherent motion (IVIM) analysis in an experimental mouse model of liver fibrosis.

Measurement of liver T1 and T2 relaxation times in an experimental mouse model of liver fibrosis

To characterize changes in relaxation times of liver using quantitative magnetic resonance imaging (MRI) in an experimental mouse model of liver fibrosis. Quantitative MRI is a potentially robust method to characterize liver fibrosis. However, correlation between relaxation times and fibrosis stage has been controversial.

Molecular MRI of liver fibrosis by a peptide-targeted contrast agent in an experimental mouse model.

ObjectivesCyclic decapeptide CGLIIQKNEC (CLT1) has been demonstrated to target fibronectin-fibrin complexes in the extracellular matrix of different tumors and tissue lesions. Although liver fibrosis is characterized by an increased amount of extracellular matrix consisting of fibril-forming collagens and matrix glycoconjugates such as fibronectin, we aimed to investigate the feasibility of detecting and characterizing liver fibrosis using CLT1 peptide-targeted nanoglobular contrast agent (Gd-P) with dynamic contrast-enhanced magnetic resonance imaging in an experimental mouse model of liver fibrosis at 7 T. Materials and MethodsGd-P, control peptide KAREC conjugated nanoglobular contrast agent (Gd-CP), and control nontargeting nanoglobular contrast agent (Gd-C) were synthesized. Male adult C57BL/6N mice (22–25 g; N = 54) were prepared and were divided into fibrosis (n = 36) and normal (n = 18) groups. Liver fibrosis was induced in the fibrosis group through subcutaneous injection of 1:3 mixture of carbon tetrachloride (CCl4) in olive oil at a dose of 4 &mgr;L/g of body weight twice a week for 8 weeks. Dynamic contrast-enhanced MRI was performed in all animals. Dynamic contrast-enhanced magnetic resonance imaging was analyzed to yield postinjection &Dgr;R1(t) maps for quantitative measurements. Histological analysis was also performed. ResultsDifferential enhancements were observed and characterized between the normal and fibrotic livers using Gd-P at 0.03 mmol/kg, when compared with nontargeted controls (Gd-CP and Gd-C). For Gd-P injection, both the peak and steady-state &Dgr;R1 of the normal livers were significantly lower than those after 4 and 8 weeks of CCl4 dosing. Liver fibrogenesis with increased amount of fibronectin in the extracellular space in insulted livers were confirmed by histological observations. ConclusionsThese results indicated that dynamic contrast-enhanced magnetic resonance imaging with CLT1 peptide-targeted nanoglobular contrast agent can detect and stage liver fibrosis by probing the accumulation of fibronectin in fibrotic livers.

Diffusion magnetic resonance monitors intramyocellular lipid droplet size in vivo

Intramyocellular lipid (IMCL) droplets are dynamic organelles whose morphology reflects their vital roles in lipid synthesis, usage, and storage in muscle energy metabolism. To develop noninvasive means to measure droplet microstructure in vivo, we investigated the molecular diffusion behavior of IMCL with diffusion magnetic resonance spectroscopy.