Correlation of MRI and histopathology after partial resection of normal brain: an experimental study in rabbits / 中华放射学杂志

ABSTRACT

Objective To investigate the manifestations of MR imaging and histopathology of early postoperative normal brain, and to define the correlation between MRI and histopathology. Methods Thirty six New Zealand rabbits weighing 2.0 to 3.0 kg were divided into 10 groups according to the different postoperative days 1 to 10 day. Six animals were in groups 3, 5, 7, 10, and 2 were in the other groups. A partial resection of the parietooccipital region was performed under the usual aseptic conditions after the animals were anesthetized intravenously with 3% pentobarbital (30 mg/kg). MR imaging procedures consisted of pre and postcontrast scanning were carried out on postoperative 1 to 10 day respectively. Brain tissue samples were obtained to be prepared for examinations immediately after MR scanning. Histopathological study was made under microscope and electron microscope. The findings of MRI were compared with pathology findings. Results (1) Surgical margin contrast enhancement on MR images could be seen 24 hours after surgery. (2) The degree of contrast enhancement increased gradually before 5 days postoperatively, and no remarkable changes were present from 5 to 10 days. (3) The disruption of blood brain barrier(BBB) is the main cause of contrast enhancement during the postoperative 3 days. After that period, mechanism responsible for contrast enhancement is the formation of neovascularity and broken BBB, an increase in the number of neovascularity play a predominant role in the contrast enhancement in normal postoperative brain tissue. Conclusion The characteristics of enhanced MRI present at the surgical margin followed a typical time course during the early postoperative period. The role of neovascularity and BBB disruption in the formation of contrast enhancement at surgical margin vary with time. Knowledge of the characteristics on postoperative MR images of the normal brain can help in differentiating benign changes from malignant gliomas residual.