Quantitative analysis of brain perfusion in healthy dogs by means of magnetic resonance imaging

Abstract

OBJECTIVE To determine values of perfusion parameters determined via MRI in the brains of healthy dogs. ANIMALS 10 healthy adult Beagles. PROCEDURES Each dog was anesthetized for MRI examination of the brain, including standard sequences and a perfusion-weighted sequence. Gadoteric acid (0.2 mmol/kg) was injected IV at a rate of 5 mL/s. A dedicated workstation was used to measure the times from contrast medium injection to arrival at an ROI (TO) and peak contrast enhancement (TTP), mean contrast medium transport time (MTT), and cerebral blood flow (CBF) in the caudate nucleus, thalamus, piriform lobe, hippocampus, semioval center, and temporal cerebral cortex. A simple mathematical model was used to compare parameter values among the various brain regions. RESULTS T0 and time to peak contrast enhancement had a significant linear relationship. A significant negative correlation was identified between T0 and CBF and, to a lesser extent, between MTT and CBF. Differences among brain regions were significant for MTT and CBF. The CBF was lowest in the semioval center, and the piriform lobe had almost 2-fold the CBF of that region. No significant differences were identified between hemispheres of the brain. CONCLUSIONS AND CLINICAL RELEVANCE Findings obtained in this study involving healthy dogs may serve as a reference for MRI perfusion measurements in specific brain regions and may help in the characterization of various brain diseases in dogs.

Dynamic Susceptibility Contrast Perfusion Magnetic Resonance Imaging Demonstrates Reduced Periventricular Cerebral Blood Flow in Dogs with Ventriculomegaly

“…However, a PET and perfusion-based MR techniques of CBF measurements were found to be highly consistent in studies involving both humans ( 24 , 37 , 38 ) and dogs ( 39 , 40 ). The values extracted from our study of clinically normal CKCSs come close to those measured in studies using MRI- or CT-based perfusion studies ( 39 , 40 ), but differ from others ( 17 , 22 ). However, several factors limit the comparison of the present investigation with other studies.…”

“…MR-perfusion techniques have proven to be feasible in dogs ( 22 , 23 ) but accuracy and validity of the method for its standard use must be further evaluated. Positron emission tomography (PET) is considered to be the gold standard for studying cerebral hemodynamics ( 36 ).…”

“…Missing standardization of acquisition parameters and use of variable postprocessing software constitutes another challenge for the comparison of data acquired in different studies ( 45 ). In addition, this study differs in that we have used combined and averaged measurements from the left and right forebrain in order to discount for known differences between the hemispheres ( 22 ).…”

Association between cerebrospinal fluid lactate concentration and central nervous system disease in dogs

“…Anesthesia can alter CBF and, therefore, possibly influence lactate concentrations. In a previous study, 27 CBF in dogs with idiopathic epilepsy was compared with a similar research project 28 in healthy dogs. It was found that anesthetics should only minimally affect lactate concentrations.…”

Infarct Evolution in a Large Animal Model of Middle Cerebral Artery Occlusion

“…TTP was defined as the time difference in peak intensity and the BAT [85,94]; 2.) TTP was defined as the time from bolus injection to peak intensity [53,54,76,95]; and 3.) TTP maps were generated using a normalization by subtracting a mean contralateral ROI of the unaffected hemisphere [54,[71][72][73]75].…”