To quantitatively analyze the changes of microcirculation perfusion in the remnant liver of rats with different types of portal vein stenosis (PVS) after 70% hepatectomy (PH) by contrast-enhanced ultrasound (CEUS).

Seventy-five Sprague-Dawley rats were randomly divided into a PH group (n=15) and two PVS groups with moderate or severe PVS following PH (PVS_M and PVS_S groups, n=30 each). According to the stenosis site, the PVS groups were further divided into either a hilar group or a non-hilar group (n=15 each). Each group was divided into 5 subgroups at different postoperative times (1, 2, 3, 7, and 14 d), with 3 rats in each group. PH was induced in all rats by 70% hepatectomy, and PVS was induced by different degrees of partial ligation at different sites of the portal vein following PH. At postoperative 1, 2, 3, 7, and 14 d, CEUS was performed to quantitatively analyze the hepatic microcirculation perfusion of the residual right lobe and papillary lobe based on the arrival time (AT), time to peak (TP), peak intensity (PI), and area under the curve (AUC). Single factor analysis of variance was used to compare the residual hepatic microcirculation perfusion parameters (AT, TP, PI, and AUC) among different groups. For groups with PVS of the same severity at different sites, independent sample t-tests were used to compare the above parameters to explore the microcirculation perfusion changes of the residual liver in different types of PVS.

The AUC of the residual right lobe in the PVS groups increased with time. The AUC in the PVS_M group was significantly higher at postoperative 7 d than at 1 d and 3 d [(4918.54±384.46) dB/s vs (2631.53±120.80) dB/s and (3117.22±434.33) dB/s, P=0.014 and 0.043, respectively], and the AUC in the PVS_S group was significantly higher at postoperative 7 d than at 1 d [(3892.09±266.81) dB/s vs (2394.68±408.53) dB/s, P=0.017]. The AT of the papillary lobe at postoperative 7 d was longer than that at 1, 2, and 3 d [(5.18±0.56) s vs (3.33±0.24) s, (3.10±0.52) s, and (3.55±0.35) s, P=0.007, 0.003, and 0.015, respectively]. At postoperative 1 d, the right-lobe PI in the PVS_M group was significantly higher than that of the PH group [(35.62±2.42) dB vs (25.11±1.60) dB, P=0.016], and at postoperative 7 d, the right-lobe PI and AUC in the PVS_S group were significantly lower than those of the PH and PVS_M groups [PI: (30.89±0.81) dB vs (39.48±1.22) dB and (37.03±2.84) dB, P=0.025 and 0.045, respectively; AUC: (3892.09±266.81) dB/s vs (5383.19±295.45) dB/s and (4918.54±384.46) dB/s, P=0.018 and 0.039, respectively]. There was no significant difference in papillary-lobe AT, TP, PI, or AUC among the PVS groups (P>0.05). At postoperative 7 d, the papillary-lobe PI in the hilar group was significantly higher than that of the non-hilar group [(35.85±1.26) dB vs (30.26±0.87) dB, t=3.655, P=0.022].

CEUS could quantitatively evaluate the hepatic microcirculation perfusion changes induced by different types of PVS following 70% PH in rats, and the right-lobe perfusion in severe PVS is significantly reduced. The microcirculation perfusion of hepatic lobes in rats with PVS of the same severity at different stenosis sites may be different.