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VX2 rabbit liver cancer, treated in vivo using bulk ultrasound ablation by miniaturized image-ablate arrays, was histologically analyzed using TTC vital stain and DAPI nucleic acid stain. VX2 cells were implanted into rabbit liver lobes and allowed to grow for 11-21 days. Liver lobes containing solid VX2 tumors were then treated with 4.8 MHz, 22.5-38.5 W/cm2 in situ intensity, unfocused ultrasound for exposure times of 20-120 s. After animal sacrifice, thermal lesions were bisected along the imaging/treatment plane, one face stained with TTC, and the other with DAPI. Levels of TTC uptake (no uptake, partial uptake, and complete uptake) in liver parenchyma corresponded to three discrete regions of tan, pink and red color. By processing images of DAPI-stained parenchymal tissue from these three regions, cellular damage was quantified. A viability index parameter incorporating the size and shape of DAPI-stained nuclei correlated significantly with levels of TTC uptake, and thus with local tissue viability. F...

In the studies reported here, the ability of echo decorrelation imaging to predict thermal ablation in vivo is tested. Radiofrequency ablation (RFA) was performed on a normal swine liver (N=5) and ultrasound ablation using image-ablate arrays was performed on a rabbit implanted with VX2 tumors (N=3). Echo decorrelation imaging was able to predict ablation and overtreatment with high accuracy for both RFA and ultrasound ablation. The effect of tissue motion was studied by comparing the mean cumulative decorrelation with and without treatment. The mean cumulative decorrelation with treatment was found to be significantly greater than the mean cumulative decorrelation without treatment (p=0.0347 for RFA, p=0.024 for ultrasound ablation). The accuracy of ablation predictions was tested using receiver operating characteristic curves and the area under the ROC curve (AUROC) was significant for ablation and overtreatment for RFA (N=5). However, the AUROC was significant for only detecting ablation for the ultras...