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The effect of midline shift on survival time in dogs with structural brain disease diagnosed on MRI
Bethany Guy1, Paul Freeman1, Sam Khan1
1Department of Veterinary Medicine, Queen's Veterinary School Small Animal Hospital, University of Cambridge, Cambridge, UK.
Abstract:
The effect of midline shift identified on brain MRI on survival time in dogs with structural brain disease is relatively unknown. This retrospective single-centered cohort study reviewed medical and imaging data of 77 dogs with structural brain lesions evident on MRI. Images were reviewed for the presence of midline shift, brain edema, foramen magnum herniation, and ventriculomegaly. Kaplan-Meier method and Cox regression analysis were undertaken to compare survival between dogs with and without midline shift. Midline shift was present in 40 of 77 (52%) dogs and absent in 37 of 77 (48%). Univariate analysis revealed that dogs with midline shift had a median survival time of 34.5 days (95% CI, 4-108 days) compared with 241 days (95% CI, 133,- days) in dogs without midline shift (hazard ratio = 2.67, 95% CI, 1.5-4.49). Multivariate Cox regression analysis revealed a hazard ratio of 3.6 (95% CI, 1.7-7.6; P-value < .001) for dogs with midline shift. Shorter median survival times remained significant in all groups after segregation based on etiological diagnosis. The significantly shorter survival times observed herein for dogs with midline shifts, regardless of etiologic cause, provide further evidence that midline shift holds value as a negative prognostic factor in diagnostic imaging.
Insights
Midline shift on brain MRI significantly reduces survival time in dogs with brain disease. This imaging finding is a crucial negative prognostic indicator, regardless of the underlying cause.
Area of Science:
- Veterinary Neurology
- Diagnostic Imaging
Background:
- The prognostic value of midline shift on magnetic resonance imaging (MRI) in dogs with structural brain disease is not well-established.
- Structural brain lesions can cause significant intracranial pressure changes.
Purpose of the Study:
- To investigate the effect of midline shift identified on brain MRI on survival time in dogs with structural brain disease.
- To determine if midline shift is a negative prognostic factor in canine neurological disease.
Main Methods:
- Retrospective single-centered cohort study of 77 dogs with structural brain lesions on MRI.
- Evaluation of MRI for midline shift, brain edema, foramen magnum herniation, and ventriculomegaly.
- Kaplan-Meier and Cox regression analyses to compare survival between dogs with and without midline shift.
Main Results:
- Midline shift was present in 52% of dogs.
- Dogs with midline shift had a significantly shorter median survival time (34.5 days) compared to those without (241 days).
- Multivariate analysis confirmed midline shift as a significant negative prognostic factor (hazard ratio = 3.6, P < .001).
Conclusions:
- Midline shift on brain MRI is a significant negative prognostic indicator in dogs with structural brain disease.
- This finding holds true irrespective of the etiological diagnosis.
- Midline shift should be considered a critical factor in assessing prognosis for canine neurological conditions.
