Reliable estimation of microvascular flow patterns in patients with disrupted blood–brain barrier using dynamic susceptibility contrast MRI

Abstract

3 Technical Efficacy: Stage 2 J. MAGN. RESON. IMAGING 2017;46:537-549.

ABCD1 dysfunction alters white matter microvascular perfusion

“…Our study has several limitations including that contrast-based magnetic resonance perfusion imaging has limited spatial resolution and derived fitted residue functions for each voxel represent an average retention across hundreds of capillary beds. The contrast agent leakage term K app is supposed to describe the flux of contrast agent from the intravascular space into the extravascular, extracellular space ( Hansen et al , 2017 ). However, the signal from each voxel consists of a combination of T 1 -weighted and T 2 *-weighted effects and intra- as well as extra-vascular compartments, which are not separable from a single gradient echo planar imaging DSC measurement ( Hansen et al , 2017 ).…”

“…Capillary transit time heterogeneity (CTH) was estimated as the standard deviation of a model transit time distribution obtained as a part of voxel-wise fitting of a vascular model to individual concentration-time curves obtained from the DSC MRI data: where, in the first term, CBF is the cerebral blood flow, C a (t) the arterial input function, h(t) the residue function. The second term represents possible tracer extravasation quantified by the apparent leakage parameter K app ( Hansen et al , 2017 ). κ is a constant dependent on the haematocrit in the arterioles and capillaries, and the density of brain tissue, but is assumed constant and set to unity.…”

“…Extravasation of contrast agent was quantified to generate the blood–brain barrier permeability maps from the tissue residue function in DSC MR Perfusion data as previously described ( Bjornerud et al , 2011 ). We note that the leakage correction part of the vascular model was slightly modified compared to Bjornerud et al (2011) to obtain an operational model for describing CTH, OEC, and CMRO 2 max in the potential presence of contrast agent leakage ( Hansen et al , 2017 ).…”

“…In this study, we apply a vascular model to dynamic susceptibility contrast (DSC) magnetic resonance perfusion acquired in an ALD patient cohort followed at our academic medical centre over a period of 10 years ( Supplementary Table 1 ) to estimate capillary transit time heterogeneity (CTH), a marker of microvascular flow dynamics; and the apparent contrast leakage constant (K app ) as an indicator of blood–brain barrier permeability ( Fig. 1 B) ( Mouridsen et al , 2006 , 2014 ; Bjornerud et al , 2011 ; Jespersen and Østergaard, 2012 ; Hansen et al , 2017 ). Given that regulation of flow across a capillary bed steers oxygen availability to match metabolic demands, our model also allowed us to examine metabolic parameters including oxygen extraction capacity (OEC) and the upper limits of metabolic rates of oxygen (CMRO 2 max ) ( Jespersen and Østergaard, 2012 ).…”

The Usefulness of Quantitative Analysis of Blood-Brain Barrier Disruption Measured Using Contrast-Enhanced Magnetic Resonance Imaging to Predict Neurological Prognosis in Out-of-Hospital Cardiac Arrest Survivors: A Preliminary Study

“…The cerebrospinal fluid (CSF)-serum albumin quotient (Q A ), calculated using CSF/serum-albumin is a gold standard numerical indicator used to determine the functional assessment of BBB disruption [ 12 ]. Contrast-enhanced magnetic resonance imaging (CE-MRI) has also been confirmed as a useful imaging test to determine the degree of BBB disruption, and this indicator can be visually confirmed [ 13 ].…”