Diagnostic Application Of Magnetic Resonance Imaging In Canine Experimental Brain Injury And Bacterial Meningitis

With the continuous development and progress of the chinese small animal diagnosis and treatment,the clinical application of magnetic resonance imaging diagnostic technology in small animals has gradually entered the popularization stage in china.More and more pet clinics have established animal medicine centers in cities.And equipped with magnetic resonance and CT.In this paper,magnetic resonance technology is used to study the diseases of canine traumatic brain injury and bacterial meningitis,aiming to further promote the application and development of magnetic resonance technology in small animal clinical diseases,and provide help for more professionals engaged in related fields.Experiment one:Using superconducting magnetic resonance to scan the normal beagle dogs brain,providing imaging basis for the structure anatomy of the normal canines’ brain,and studying the anatomical structure and magnetic resonance imaging anatomical structure of normal dogs.In this research,2 healthy young beagle dogs(1 for male,1 for female)were subjected to T1WI、T2WI、FLAIR、T1+C、DWI and MRA multiple sequence scans using 1.5T superconducting magnetic resonance,to obtain normal magnetic resonance brain images of dogs.After the MR scan,the experimental dogs were euthanized.The canine brain was removed and soaked in formalin for three weeks.Then using a slicer blade to slice the canine brain.Taking pictures to normal canine brain specimens,using Photoshop CC to process the magnetic resonance images and tomographic images of canine brain,obtained normal brain magnetic resonance atlas and cerebral tomographic anatomy atlas,which provides a basis for the subsequent study of canine brain neuropathy.Experiment two:In order to establish a model of diffuse traumatic brain injury in dogs,and to study the diagnostic value of magnetic resonance in different degrees of traumatic brain injury in dogs,and to provide imaging reference for clinical diagnosis and treatment.Eighteen 1 year old Beagles were randomly divided into control group(3 dogs)and traumatic brain injury model group(5 dogs in each subgroup).The self-made vertical falling body striking model device was used to drop the 100g weight from 50cm、75cm and 100cm respectively to hit the right frontal lobe after the skull fenestration,resulting in varying degrees of diffuse traumatic brain injury.MRI was used to perform T1WI、T2WI and FLAIR scans on canine wounds.The MRI features of different lesions,Glasgow Coma Scale(MGCS)and prognosis were analyzed.There were no abnormalities in MRI images in the control group.Mild edema of the cerebral cortex was observed in the mild injury group.The prognosis of MGCS was good.MRI of the moderate injury group showed moderate edema of the gray matter and the white matter,slight deviation of the midline,and the prognosis of MGCS was cautious.MRI showed severe edema of the cerebral hemisphere at the wound,cortical hematoma,ventricular dilatation,severe midline shift,and poor prognosis of MGCS.The self-made vertical falling body attack model can simulate diffuse traumatic brain injury in dogs.MRI has important diagnostic value for canine traumatic brain injury.MGCS has important prognostic evaluation in traumatic brain injury.Experiment three:To establish a model of bacterial meningitis in canine and evaluate the diagnostic value of Gd-DTPA enhanced magnetic resonance imaging in canine infected with different concertration of bacterial meningitis,18 native dogs were randomly divided into a saline control group with 3 dogs and 3 bacterial meningitis model group with 5 dogs in each.A model of canine bacterial meningitis was established by cerebellar medullary puncture using different concentrations(4×106,4×107,4×108 cfu/mL)of Escherichia coli in each group,while an equal volume of saline was substituted for Escherichia coli in the control group.The clinical symptoms of the animals after modeling were observed,body temperature,whole blood leukocytes and leukocytes in the cerebrospinal fluid were recorded before and after modeling.Head-enhanced scan was performed pre-modeling and 1 day and 3days modeling,and the imaging differences of MRI contrast enhancement in different concentration groups.After the end of the experiment,the anatomical fixation was performed to observe the anatomical changes of the canine brain.The result showed significantly differences in body temperature,whole blood leukocytes,and cerebrospinal fluid leukocytes count.MRI images showed no abnormality in the saline control group.No abnormalities were observed in the the 4×106 cfu/mL group except for slight enhance in the pia mater in the upper part of the corpus callosum.In the 4×107 cfu/mL group,the brain parenchyma sulcus was deepened and the pia mater was obviously enhanced while other abnormalities were not observed.The 4×108 cfu/mL group results showed thickened dura and significantly enhanced pia mater.The brain parenchyma sulcus was deepened,and the lateral ventricle was moderately dilated.The anatomical results were consistent with the MRI image results.In conclusion,bacterial meningitis models were successfully induced by puncture of Escherichia coli in the cisterna magna,and that the degrees of meningitis were controlled by the concentration of bacteria injected.Enhanced magnetic resonance imaging were great significance for the diagnosis of bacterial meningitis of different degrees.