Histopathological correlation to MRI findings during and after laser-induced thermotherapy in a pig pancreas model.

Abstract

To investigate whether percutaneous laser-induced thermotherapy (LITT) with continuous magnetic resonance (MR) monitoring of thermal effects within the pancreas is feasible in a porcine model. Laser applicators were placed in the pancreas of 15 female pigs. A temperature-sensitive (thermo--fast low-angle shot) sequence was used for continuous monitoring of thermal effects during LITT at 1.5 T. Follow-up MR images were acquired, the pigs were observed for 7 days, and then a pathological examination was performed after sacrifice. Continuous MR monitoring visualized thermal effects in pancreatic tissue and thermal damage of the spleen (n = 1), the left kidney (n = 1), and peripancreatic fat (n = 4) but missed the thermal damage of the duodenum (n = 2). Thermal-induced lesions (10--32-mm diameter) were clearly visualized on contrast-enhanced T1-weighted images. Laser-induced thermotherapy of pancreatic tissue was feasible in this porcine model, and online monitoring was practicable. Further studies are necessary to increase the accuracy of online MR imaging of thermal effects.