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A quantitative MRI method for imaging blood-brain barrier leakage in experimental traumatic brain injury.

Li W, Long JA, Watts LT, Jiang Z, Shen Q, Li Y, Duong TQ - PLoS ONE (2014)

Bottom Line: A series of T1-weighted gradient echo images were acquired and fitted to the extended Kety model with reversible or irreversible leakage, and the best model was selected using F-statistics.We applied this method to study the rat brain one hour following controlled cortical impact (mild to moderate TBI), and observed clear depiction of the BBB damage around the impact regions, which matched that outlined by Evans Blue extravasation.Unlike the relatively uniform T2 contrast showing cerebral edema, Ktrans shows a pronounced heterogeneous spatial profile in and around the impact regions, displaying a nonlinear relationship with T2.

View Article: PubMed Central - PubMed

Affiliation: Research Imaging Institute, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America; Department of Ophthalmology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America.

ABSTRACT
Blood-brain barrier (BBB) disruption is common following traumatic brain injury (TBI). Dynamic contrast enhanced (DCE) MRI can longitudinally measure the transport coefficient Ktrans which reflects BBB permeability. Ktrans measurements however are not widely used in TBI research because it is generally considered to be noisy and possesses low spatial resolution. We improved spatiotemporal resolution and signal sensitivity of Ktrans MRI in rats by using a high-sensitivity surface transceiver coil. To overcome the signal drop off profile of the surface coil, a pre-scan module was used to map the flip angle (B1 field) and magnetization (M0) distributions. A series of T1-weighted gradient echo images were acquired and fitted to the extended Kety model with reversible or irreversible leakage, and the best model was selected using F-statistics. We applied this method to study the rat brain one hour following controlled cortical impact (mild to moderate TBI), and observed clear depiction of the BBB damage around the impact regions, which matched that outlined by Evans Blue extravasation. Unlike the relatively uniform T2 contrast showing cerebral edema, Ktrans shows a pronounced heterogeneous spatial profile in and around the impact regions, displaying a nonlinear relationship with T2. This improved Ktrans MRI method is also compatible with the use of high-sensitivity surface coil and the high-contrast two-coil arterial spin-labeling method for cerebral blood flow measurement, enabling more comprehensive investigation of the pathophysiology in TBI.

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Ktrans values using different models in a representative TBI brain.A: The location for the selected voxels for the voxel-wise intensity comparison in panel B. C: Label of ROIs. D: The Ktrans values in these ROIs using different approaches. Data were presented as mean ± standard error of each ROI.
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pone-0114173-g006: Ktrans values using different models in a representative TBI brain.A: The location for the selected voxels for the voxel-wise intensity comparison in panel B. C: Label of ROIs. D: The Ktrans values in these ROIs using different approaches. Data were presented as mean ± standard error of each ROI.

Mentions: Fig. 6 illustrated the impact of model selection on the Ktrans determination in this TBI brain. Along the red dotted line (Fig. 6A), Model 3 was selected more in the impact region, and was selected less in the remote region (Fig. 6B), when compared to Model 2. For further comparison, three different ROIs were drawn in the focal lesion, perifocal, and remote regions. The focal lesion region (Fig. 6C, ROI #1) showed the strongest BBB leakage, in which 100% of the voxels were better fit by Model 3 with reversible leakage. If reversible flux was neglected, the Ktrans value was significantly underestimated (P<0.01, Fig. 6D). In the perifocal region (Fig. 6C, ROI #2), 19% voxels were better fit by Model 3. Ktrans values determined by Model 2 and Model 3 were similar (P = 0.5). In the healthy region remote from the impact site (Fig. 6C, ROI #3), only 6% of voxels were better fit by Model 3. If reversible leakage was applied to all voxels (Model 3), the Ktrans was much nosier and significantly overestimated (P<0.01).


A quantitative MRI method for imaging blood-brain barrier leakage in experimental traumatic brain injury.

Li W, Long JA, Watts LT, Jiang Z, Shen Q, Li Y, Duong TQ - PLoS ONE (2014)

Ktrans values using different models in a representative TBI brain.A: The location for the selected voxels for the voxel-wise intensity comparison in panel B. C: Label of ROIs. D: The Ktrans values in these ROIs using different approaches. Data were presented as mean ± standard error of each ROI.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4257611&req=5

pone-0114173-g006: Ktrans values using different models in a representative TBI brain.A: The location for the selected voxels for the voxel-wise intensity comparison in panel B. C: Label of ROIs. D: The Ktrans values in these ROIs using different approaches. Data were presented as mean ± standard error of each ROI.
Mentions: Fig. 6 illustrated the impact of model selection on the Ktrans determination in this TBI brain. Along the red dotted line (Fig. 6A), Model 3 was selected more in the impact region, and was selected less in the remote region (Fig. 6B), when compared to Model 2. For further comparison, three different ROIs were drawn in the focal lesion, perifocal, and remote regions. The focal lesion region (Fig. 6C, ROI #1) showed the strongest BBB leakage, in which 100% of the voxels were better fit by Model 3 with reversible leakage. If reversible flux was neglected, the Ktrans value was significantly underestimated (P<0.01, Fig. 6D). In the perifocal region (Fig. 6C, ROI #2), 19% voxels were better fit by Model 3. Ktrans values determined by Model 2 and Model 3 were similar (P = 0.5). In the healthy region remote from the impact site (Fig. 6C, ROI #3), only 6% of voxels were better fit by Model 3. If reversible leakage was applied to all voxels (Model 3), the Ktrans was much nosier and significantly overestimated (P<0.01).

Bottom Line: A series of T1-weighted gradient echo images were acquired and fitted to the extended Kety model with reversible or irreversible leakage, and the best model was selected using F-statistics.We applied this method to study the rat brain one hour following controlled cortical impact (mild to moderate TBI), and observed clear depiction of the BBB damage around the impact regions, which matched that outlined by Evans Blue extravasation.Unlike the relatively uniform T2 contrast showing cerebral edema, Ktrans shows a pronounced heterogeneous spatial profile in and around the impact regions, displaying a nonlinear relationship with T2.

View Article: PubMed Central - PubMed

Affiliation: Research Imaging Institute, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America; Department of Ophthalmology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America.

ABSTRACT
Blood-brain barrier (BBB) disruption is common following traumatic brain injury (TBI). Dynamic contrast enhanced (DCE) MRI can longitudinally measure the transport coefficient Ktrans which reflects BBB permeability. Ktrans measurements however are not widely used in TBI research because it is generally considered to be noisy and possesses low spatial resolution. We improved spatiotemporal resolution and signal sensitivity of Ktrans MRI in rats by using a high-sensitivity surface transceiver coil. To overcome the signal drop off profile of the surface coil, a pre-scan module was used to map the flip angle (B1 field) and magnetization (M0) distributions. A series of T1-weighted gradient echo images were acquired and fitted to the extended Kety model with reversible or irreversible leakage, and the best model was selected using F-statistics. We applied this method to study the rat brain one hour following controlled cortical impact (mild to moderate TBI), and observed clear depiction of the BBB damage around the impact regions, which matched that outlined by Evans Blue extravasation. Unlike the relatively uniform T2 contrast showing cerebral edema, Ktrans shows a pronounced heterogeneous spatial profile in and around the impact regions, displaying a nonlinear relationship with T2. This improved Ktrans MRI method is also compatible with the use of high-sensitivity surface coil and the high-contrast two-coil arterial spin-labeling method for cerebral blood flow measurement, enabling more comprehensive investigation of the pathophysiology in TBI.

Show MeSH
Related in: MedlinePlus