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Objective: To explore the value of edema ring around the ablation zone on FS-T2WI for early phase effect evaluation of radiofrequency ablation (RFA) for treatment of malignant hepatic tumors. Methods: Totally 18 patients with liver cancer and 4 with liver metastasis who underwent RFA therapy were enrolled. Plain MR images were obtained to observe the morphological features of the edema ring around the ablation zone on FS-T2WI on the third day after RFA. Plain and multiphase enhanced MRI were obtained after RFA to observe the effect, as well as tumor markers. The value of continuity of edema ring on FS-T2WI for evaluating the effect of RFA was assessed. Results: High-signal edema ring was seen around the ablation zone on FS-T2WI in all 22 cases. The edema rings were continuous in 19 cases, among them the thickness of the edema rings were uniform in 11 cases, while were uneven but with regular shape and clear boundary in the other 8 cases. No abnormal enhancement was detected on the following enhanced MRI after RFA, and the tumor markers were stable in above 19 cases, both suggesting completed ablation. The edema rings were discontinuous in 3 cases of liver cancer, with protruding slightly high signal nodule which enhanced on MRI 1 month after RFA, and the serum alpha-fetoprotein were elevated, suggesting that the ablation area did not completely cover the tumor area, and the ablations were not complete. Conclusion: The edema ring around the ablation zone on plain FS-T2WI early phase after RFA has certain value in assessing the effect of RF for malignant liver tumors, especially for short-term effect of RFA.
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Objective To investigate the effect of 3-bromopyruvate (3-BrPA) on transplanted rectal tumors in experimental rabbit models. Methods A total of 60 New Zealand white rabbits with transplanted rectal tumor were randomly and equally divided into low-dose (0.5 mmol/L), medium-dose (1.0 mmol/L), high-dose (2.0 mmol/L) treatment groups and saline control group with 15 rabbits in each group. Arterial perfusion of 10 ml 3-BrPA with concentration of 0.5 mmol/L, 1.0 mmol/L and 2.0 mmol/L via caudal mesenteric artery was respectively employed for the rabbits of the corresponding treatment group; the control group was perfused with equal amounts of saline. Four days later, rectal tumors were removed by vivisection. The necrosis degree of tumor cells was determined by microscopic examination, and the necrosis rate was calculated. The effect of different 3-BrPA concentrations on the rectal tumor was evaluated. Results The rectal tumor transplantation and transcatheter 3-BrPA or saline perfusion was successfully completed in all 60 experimental rabbits. Microscopically, tumor cells showed different degrees of damage in experimental rabbits. In low-dose (0.5 mmol/L) treatment group, gradeⅠnecrosis was observed in 3 rabbits, gradeⅡin 11 rabbits, and gradeⅢin one rabbit;the effective rate was 6.7%. In medium-dose (1.0 mmol/L) treatment group, gradeⅡnecrosis was seen in 2 rabbits, grade Ⅲ in 10 rabbits, and grade Ⅳ in 3 rabbits; the effective rate was 86.6%. In high-dose (2.0 mmol/L) treatment group, gradeⅢnecrosis was detected in 2 rabbits and gradeⅣin 13 rabbits;the effective rate was 100.0%. In the saline control group, grade I necrosis was observed in 15 rabbits. Statistically significant differences in tumor necrosis rate and effective rate existed between medium-dose (1.0 mmol/L) treatment group and high-dose (2.0 mmol/L) treatment group (P<0.05). Statistically significant differences in tumor necrosis rate also existed between each other among the four groups with necrosis of gradeⅠto gradeⅣ(P<0.05). 3-BrPA had obvious therapeutic effect, while it showed no damage to the normal intestinal tissue. Conclusion For the treatment of transplanted rectal tumor in rabbit models, arterial infusion of 3-BrPA has certain therapeutic effect. In the high-dose group, the necrosis rate and effective rate are the highest, and the therapeutic results are the most significant.
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Objective To investigate the potential of AFP-targeted ultrasmall superparamagnetic particles of iron oxide (USPIO) molecular probe in specific detection of hepatocellular carcinoma (HCC) with MRI.Methods The targeted probe was synthesized by conjugating AFP antibody with modified USPIO.Two groups treated with AFP-USPIO and USPIO were set up in the study.The HepG2 cells were incubated with AFP-USPIO or USPIO (100 μg/ml) respectively with the dosage of 50 μ1,100 μl or 150 μl for 4 hours,followed by MR imaging in vitro.The signal-noise ratio (SNR) of the cells on T2-weighted image (T2WI) was measured.The rat models with orthotopic HCC were divided into two groups with 5 rats for each group at random.Pre-and post-contrast enhanced (after 1 hour) MR imaging were performed with caudal vein injection at a dosage of 20μg/ml.The contrast noise ratio (CNR) on T2WI and the difference of CNR between pre-and post-enhancement or between both groups were calculated.The relationship of SNR or CNR with the iron particles in cells or tumors was confirmed by Prussian blue iron staining.Results Cytology experiment showed the SNR in both groups was decreased with the increase of the dosage of AFP-USPIO or USPIO,indicating statistically significantdifference in SNR among three different doseage groups (P＜0.05).Prussian blue iron staining showed that the iron particles in cells were increased with the increase of AFP-USPIO dosage,and was negatively correlated with SNR (P=0.00,r=-0.926).However,the iron particles were less in cells in USPIO group.The CNRs of liver tumors in Wistar rat of pre-and post-AFP-USPIO injection were 2.05±0.88 and 0.96±0.31 respectively,indicating a significant difference (P=0.028,t=3.380).However,the CNRs in USPIO group,2.25±1.50 and 2.57±1.49,showed no statistical difference (P=0.275,t=1.263).The CNR after enhancement also had a statistical difference between both groups(P=0.042,t=3.487).Pathological results confirmed more iron particles in tumor tissues in AFP-USPIO group,whereas less in USPIO group.Conclusion AFP-USPIO molecular probes can initiatively target to the HepG2 cells and the liver cancer of rat models expressing AFP,which may help to achieve the specificity of MR imaging in the diagnosis of HCC.