Dynamic gadolinium-enhanced MRI imaging in a mouse model of traumatic brain injury

Abstract

The aim: This study aimed to use gadolinium contrast agent in assessing the integrity of BBB changes that is affected by TBI Background: Traumatic brain injury (TBI) also called intracranial injury refers to the injuries sustained by the brain as a result of an external mechanical force on the head. The assessment of the impacts resulting from TBI in a patient is the damage and disruption it causes on the bloodbrain barrier (BBB). A damaged BBB increases permeability to large molecules as well as contrast MRI agents such as gadolinium (Gd) that can be detected by the Dynamic ContrastEnhanced MRI (DCE-MRI) as it accumulates in damaged tissues. Methods: Six laboratory mice were subjected to experimental brain injuries. After the injury infliction was performed, the animals were injected with 200 µl that contained 50 µl Gadovist gadolinium and about 10MBq of 18F-PBR111, with the remaining 140 µl in the injection composed of saline. Afterwards, two simultaneous images were taken using both PET and MRI. Results: There was a greater loss in signal intensities after a 30-day period compared to a sevenday period. There was a significant difference 7 days post-injury with P value= 0.000215. When the blood-brain barrier was disrupted, the Gadovist agent was extravasated, which enhanced the signal intensity (SI) on the MRI-PET image. The overall percentage of SI for the normal brain was lower compared to that of the damaged brain. Conclusion: The experiment established that TBI is indeed a pathophysiological factor in the damage and disruption of BBB. A disrupted BBB exhibits a higher permeability and leads to quantitative changes in parameters such as microvascular permeability, interstitial volume fraction, cerebral blood flow, and cerebral blood volume fraction.