Evaluating traumatic brain injury using conventional magnetic resonance imaging and susceptibility-weighted imaging in dogs

Abstract

Susceptibility-weighted imaging (SWI) is a magnetic resonance imaging (MRI) sequence used for evaluating traumatic brain injury (TBI). Although SWI is being increasingly used in veterinary medicine, there are no systematic studies regarding its use. We aimed to evaluate TBI lesions by using conventional MRI and SWI in 11 dogs and determine the correlation between clinical status and conventional MRI or SWI findings. The modified Glasgow coma scale (MGCS) at presentation and a previously used MRI grading system (MRGr; grades 1–6) were used to evaluate the brain lesions, and correlations between MGCS score and each MRGr were assessed. Conventional MRI revealed 23 lesions in 11 dogs with variable MGCS scores (range: 11–17). SWI showed comparable findings for all of the lesions except for subdural hemorrhage, and it revealed additional lesions in four dogs. The median MRGr was 2 on both conventional MRI and SWI. The MRGr of the conventional MRI assessments and the MGCS scores showed a significant negative correlation ( r = −0.685). In conclusion, SWI had better TBI lesion-detection ability, but conventional MRI had a better correlation with early clinical status and subdural hemorrhage. Thus, a combination of conventional MRI and SWI examinations can improve TBI diagnosis in dogs.

Susceptibility weighted imaging at 1.5 Tesla magnetic resonance imaging in dogs: Comparison with T2*‐weighted gradient echo sequence and its clinical indications

“…5,6 In one of the trauma cases included in this study, temporal subdural hemorrhage was identified on T1-weighted precontrast and on SWI sequences, but not seen in T2*-weighted GE. This is not reflective of the findings of Noh et al 21 where subdural hemorrhage was not identified by SWI in one case due to susceptibility artifacts at the skull base-air interface. The discrepancy between their study and our findings may be due to the location of the subdural hemorrhage, and differences in acquisition protocols between the two studies.…”

“…11,[18][19][20] Recently, Noh et al assessed the performance of SWI for assessment of canine brain trauma, however, no comparison with T2*-weighted GE sequence was attempted. 21 Published clinical studies comparing the utility of SWI to T2*weighted GE sequences in dogs are currently lacking.…”

Intracranial Lesion Detection and Artifact Characterization: Comparative Study of Susceptibility and T2*-Weighted Imaging in Dogs and Cats

“…This phenomenon is proportional to the field strength ( 18 ). Although the feasibility of the sequence has been reported in veterinary medicine ( 1 , 3 ), evaluation of SWI phase images and artifact characterization are currently lacking.…”

“…Absent or minuscule air-filled frontal sinuses are known in some small-breed dogs, including many brachycephalic breeds ( 22 ). The current literature describing the use of SWI in veterinary medicine reports field strength of 1.5 Tesla (T) ( 1 , 3 ). In human medicine, lesion contrast and venous vessel contrast are increased in 3 compared with 1.5 T; however, susceptibility artifacts caused by anatomical structures are also more prominent ( 17 ).…”

“…In human neuroimaging, SWI is used predominantly for the evaluation of intracranial hemorrhage, vascular malformations, traumatic brain injury, brain tumors, congenital, infections, and neurodegenerative disorders ( 6 , 7 , 15 ). In veterinary medicine, the utility of SWI sequence has been proven in dogs affected by traumatic brain injury and for detecting hemorrhage and identifying intracranial venous abnormalities ( 1 , 3 ). A recently published study demonstrated that venous structures and hemorrhagic lesions are more conspicuous in SWI than in T2 * WI in dogs ( 3 ), but studies in cats as well as the influence of unwanted artifacts on the image evaluation are currently lacking.…”