Establishment And Application Of Superconducting MRI Examination Program For Canine Intervertebral Disc Disease

Magnetic resonance imaging(MRI)has received increasing attention in recent years with the development of veterinary treatment techniques.The emergence of MRI can improve the accuracy of the diagnosis of intervertebral disc disease,which is usually caused by mild paralysis or paralysis in dogs.The domestic application of high field strength superconducting MRI in intervertebral disc disease is still in the exploration stage.Therefore,the purpose of this study was to acquire images of the spinal nervous system of healthy dogs using superconducting MRI at 1.5 T,to establish an anatomical atlas of MRI images of major sections of the normal canine spine and appropriate scan protocols and parameters,and to apply them clinically in pets.MRI scans were performed on six healthy pastoral dogs,and 52 cases of dogs diagnosed with intervertebral disc disease after neurological examination and MRI scans were collected from a hospital in Beijing from January 2019 to March 2021,and the MRI images of these cases were analyzed to obtain the appropriate scan protocol and sequence parameters for scanning the spinal nervous system of dogs.Three of these cases with different types of intervertebral disc disease were selected for analysis in combination with neurological examination and MRI images.The experiment obtained 25 MRI images of the cervical and thoracolumbar spine with anatomical annotation of the main MRI sections.The analytical study of the experimental canine examinations and clinical cases led to the selection of the fast spin echo(FSH)technique for canine MRI spinal nervous system sweeps with T2 WI,T1WI,and fat-suppressed T2-weighted(T2WI-FS)scan sequences.FSH T2 WI sequence parameters: repetition time(TR)=1800 ms,echo time(TE)=104.8 ms,echo train length(ETL)=11.FSH T1WI: TR=450 ms,TE=12.9 ms,ETL=3.T2WI-FS: TR=2000 ms,TE=88.9 ms,ETL=13.ETL=13.Number of excitation(NEX)is 3-5,slice thickness=2.0 mm,slice gap=0.2 mm,field of view(FOV): 180-220.Adjust the parameters appropriately according to the clinic.Increasing NEX can increase the image signal-to-noise ratio,but it will increase the scan time.Increasing the FOV can increase the signal-to-noise ratio,but will reduce the resolution and increase the scan time.We can reduce the scan time by reducing the phase encoding range after we have determined the lesion range,which narrows the sweeping range.We retrospectively analyzed three clinical cases of canine intervertebral disc disease,including Hansen Ⅰ intervertebral disc extrusion of canine thoracolumbar,Hansen Ⅱ intervertebral disc protrusion of canine lumbar vertebra,and Hansen Ⅰ intervertebral disc extrusion of canine cervical vertebra,and explained the characteristics on the respective MRI images.The anatomical labeling of the main MRI sections and the scan protocols and parameters obtained from the image analysis of MRI of canine intervertebral disc diseases and the scanning of experimental dogs can lay the theoretical foundation and provide research data for the application of superconducting MRI for the diagnosis of canine intervertebral disc diseases.