Figure 5.

The application of M-Gd-NL in discriminating mild and severe AP.

Notes: After mild or severe AP models were established, the rats bearing AP were injected with M-Gd-NL via the tail veins (0.1 mmol/kg Gd-DTPA, 5 rats per group). (A) The rats were imaged five times by MRI (before treatment: pre-contrast; 5 min after injection: post 5 min; 60 min after injection: post 60 min; 120 min after injection: post 120 min; 180 min after injection: post 180 min). T₁WI MRI scans (in the same plane) of the pancreases of rats in each group were performed using the 3.0T Siemens Healthcare MRI system by wrist coil. The T₁WI images of rat model in each group were obtained. (B) For quantitative analysis, the T₁WI SNR of the ROIs (which were manually drawn on the pancreas images; as shown with red and white dotted lines), and (C) ΔSNR of the ROIs were presented as the change of SNR from baseline as equation: ΔSNR = (post-contrast SNR – pre-contrast SNR)/pre-contrast SNR. In order to determine whether T₁ relaxation times of ROIs can predict the status of pancreas, (D) the corresponding map images were obtained by quantitative T₁ mapping based on a respiratory-gated variable-flip-angle technique. (D) Maps of T₁ were created with custom Matlab scripts (TheMathworks, Natick, MA, USA). (E) The data were presented as the change in T₁ from baseline, ΔT₁, caused by the presence of the contrast agent M-Gd-NL within the ROIs at time as outlined in equations: ΔT₁ = (pre-contrast T₁ – post-contrast T₁)/pre-contrast T₁. All comparisons were performed between the two groups by one-way analysis of variance with Newman–Keuls posttest. Data are expressed as mean ± standard deviation (n=5). *P<0.05; **P<0.01; ***P<0.001.

Abbreviations: AP, acute pancreatitis; Gd-DTPA, gadolinium-diethylenetriaminepentaacetic; Gd-NL, Gd-DTPA-loaded liposomes; M-Gd-NL, gadolinium-diethylenetriaminepentaacetic-loaded mannosylated liposomes; MRI, magnetic resonance imaging; ROIs, regions of interests; SNR, signal-to-noise ratio; T₁WI, T₁-weighted.