Comparison of a single perfusion device and an internally cooled cluster device: laboratory experience in ex vivo liver tissue with longer duration of energy application.

PURPOSE: To determine with comparison of two different monopolar radiofrequency (RF) devices whether a longer duration of energy application has an effect on coagulation necrosis in ex vivo bovine liver tissue. MATERIALS AND METHODS: The volume and short- and long-axis diameters of the coagulation were assessed in ex vivo bovine livers after RF application for 5-60 minutes. A power of 60 W was used for the single perfusion applicator (n = 48), and a power of 200 W was used for the internally cooled cluster applicator (n = 48). Reproducibility and coagulation shape were assessed and compared. For statistical evaluation, the mean values of the dimensions were compared by using analysis of variance with the following factors: applicator, RF duration, and their interaction. RESULTS: RF application up to 60 minutes produced a mean maximum volume of coagulation of 116.8 cm(3)(95% confidence interval [CI]: 98.4 cm(3), 138.8 cm(3)) for the single perfusion device and 89.5 cm(3)(95% CI: 75.4 cm(3), 106.3 cm(3)) for the internally cooled cluster applicator. For both devices, duration of energy application up to 60 minutes showed a significant interaction for the volume and the short- and long-axis diameters of coagulation (P < .0001). The volumes of coagulation necrosis induced with the internally cooled cluster applicator were more reproducible than those induced with the single perfusion applicator (P < .0001). The shape of the lesion was closer to a sphere (mean shape ratio, 0.98) for the internally cooled cluster than for the single perfusion applicator (mean shape ratio, 1.21) (P < .0001). CONCLUSIONS: There is a significant interaction between RF duration and both RF devices influencing the dimensions of coagulation. Longer durations of energy application expand the volume of coagulation with a better reproducibility and more spherical shape of coagulation for the internally cooled cluster device.

Multifocal dysembryoplastic neuroepithelial tumor with signs of atypia after regrowth.

We report the case of a multifocal dysembryoplastic neuroepithelial tumor (DNT) in a 7-year-old girl with local tumor regrowth 6 years later. The tumor was localized in the right parietal lobe extending from the cortex into the periventricular white matter. After subtotal resection of a histopathologically confirmed DNT we observed unexpected tumor progression in long-term follow-up. Therefore, a second surgery was performed when the patient was 14 years of age. In neuropathological examination of the second specimen the tumor showed an increased cellularity and pleomorphism, microvascular proliferations, an elevated proliferative activity (MIB1-index focally up to 10%) and cellular atypia not typical for WHO grade I DNT. Furthermore, MRI studies showed additional supratentorial and infratentorial lesions which remained stable over years and are also well consistent with DNTs. Thus, an unusual form of a DNT with multifocal lesions, local regrowth and morphological transformation is supposed.

Application of poly-lactide-co-glycolide-microspheres in the transarterial chemoembolization in an animal model of hepatocellular carcinoma.

AIM: To introduce an animal model of hepatocellular carcinoma (HCC) in ACI-rats, and to evaluate the therapeutic effects of Poly-lactide-co-glycolide (Plcg) -microspheres in the transarterial chemoembolization (TACE) in this model, as well the value of this model in the experiments of interventional therapy. METHODS: Subcapsular implantation of a solid Morris Hepatoma 3 924A (1 mm(3)) in the livers was carried out in 11 male ACI-rats. The tumor volume (V1) was measured by magnetic resonance imaging (MRI) (13 days after implantation). After laparotomy and retrograde placement of catheter into the gastroduodenal artery (14 days after implantation), the following protocols of interventional treatment were performed: (A) mitomycin C+Poly-lactide-co-glycolide (Plcg)-microspheres (n=4); (B) 0.9 % NaCl (control group, n=7). 13 days after these therapies the change of the tumor volume (V2) was determined by MRI again. RESULTS: The success rate of tumor implantation reached to 100 %. The mean tumor volume before TACE (V1) were 0.082 cm(3) in group A and 0.096 cm(3) in group B respectively. The mean tumor volume after TACE (V2) were 0.230 cm(3) in group A and 1.347 cm(3) in group B respectively. The mean V2/V1 were 2.860 in group A and 27.120 in group B respectively. Compared to the control group (group B), groups A showed a significant reduction of tumor growth (P=0.004) in the period of observation. CONCLUSION: The growth of liver tumor could be obviously prevented by utilizing Plcg-mitomycin-microspheres in TACE in animal model. This rat model of HCC is suitable for the experimental studies of interventional therapy.