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Permeability Parameters Measured with Dynamic Contrast-Enhanced MRI: Correlation with the Extravasation of Evans Blue in a Rat Model of Transient Cerebral Ischemia.

Choi HS, Ahn SS, Shin NY, Kim J, Kim JH, Lee JE, Lee HY, Heo JH, Lee SK - Korean J Radiol (2015)

Bottom Line: Sprague-Dawley rats (n = 13) with transient middle cerebral artery occlusion were imaged using a 3-tesla MRI with an 8-channel wrist coil.All permeability parameters (K(trans), ve, and vp) showed a linear correlation with extravasation of Evans blue.Among them, K(trans) showed highest values of both the correlation coefficient and the coefficient of determination (0.687 and 0.473 respectively, p < 0.001).

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology, College of Medicine, The Catholic University of Korea, Seoul 137-701, Korea.

ABSTRACT

Objective: The purpose of this study was to correlate permeability parameters measured with dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) using a clinical 3-tesla scanner with extravasation of Evans blue in a rat model with transient cerebral ischemia.

Materials and methods: Sprague-Dawley rats (n = 13) with transient middle cerebral artery occlusion were imaged using a 3-tesla MRI with an 8-channel wrist coil. DCE-MRI was performed 12 hours, 18 hours, and 36 hours after reperfusion. Permeability parameters (K(trans), ve, and vp) from DCE-MRI were calculated. Evans blue was injected after DCE-MRI and extravasation of Evans blue was correlated as a reference with the integrity of the blood-brain barrier. Correlation analysis was performed between permeability parameters and the extravasation of Evans blue.

Results: All permeability parameters (K(trans), ve, and vp) showed a linear correlation with extravasation of Evans blue. Among them, K(trans) showed highest values of both the correlation coefficient and the coefficient of determination (0.687 and 0.473 respectively, p < 0.001).

Conclusion: Permeability parameters obtained by DCE-MRI at 3-T are well-correlated with Evans blue extravasation, and K(trans) shows the strongest correlation among the tested parameters.

No MeSH data available.


Related in: MedlinePlus

Selection of arterial input function (AIF) for analysis of permeability parameters.A. Region of interest was set at region of left cervical internal carotid artery (green color). Venous flow is depicted in blue. B. Time-concentration of gadolinium curve showed rapid upslope and early peak of gadolinium concentration (GD), suggestive of appropriate selection of arterial flow.
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Figure 1: Selection of arterial input function (AIF) for analysis of permeability parameters.A. Region of interest was set at region of left cervical internal carotid artery (green color). Venous flow is depicted in blue. B. Time-concentration of gadolinium curve showed rapid upslope and early peak of gadolinium concentration (GD), suggestive of appropriate selection of arterial flow.

Mentions: Permeability parameters were calculated by off-line PRIDE tools provided by Philips Medical Systems (Best, The Netherlands), which is based on the pharmacokinetic model of Tofts et al. (31). The two compartment model of Tofts assumes intravascular and extravascular extracellular spaces, which are divided by the BBB. The degree of contrast leakage from the intravascular space to the extravascular extracellular space is referred to as Ktrans. The volume fraction of the extravascular extracellular space is referred to as ve. The volume fraction of plasma space is referred to as vp. Those permeability parameters were calculated by means of iteration between time-intensity curves of the artery and tissue in assumption of the Tofts model (2731). Arterial input function was measured at the area of left internal carotid artery (Fig. 1A) and its time-concentration curve was checked (Fig. 1B). Because extravasation of Evans blue was prominent near the slices of Bregma-1.60 mm, they were targeted for analysis. Briefly, post-processing consisted of motion correction of pixels from dynamic images, T1-mapping using different flip angles (5° and 15°), co-registration of pixels on the T1-map, arterial input function estimation, and pharmacokinetic modeling. All these processes were automatically performed by PRIDE tools. Different regions of interest (ROIs) were placed in the cortex and basal ganglia in the ipsilateral and contralateral hemispheres of transient MCA occlusion. Therefore, four different ROIs were drawn per rat. Then, the three types of permeability parameters (Ktrans, ve, and vp) were calculated on each ROI.


Permeability Parameters Measured with Dynamic Contrast-Enhanced MRI: Correlation with the Extravasation of Evans Blue in a Rat Model of Transient Cerebral Ischemia.

Choi HS, Ahn SS, Shin NY, Kim J, Kim JH, Lee JE, Lee HY, Heo JH, Lee SK - Korean J Radiol (2015)

Selection of arterial input function (AIF) for analysis of permeability parameters.A. Region of interest was set at region of left cervical internal carotid artery (green color). Venous flow is depicted in blue. B. Time-concentration of gadolinium curve showed rapid upslope and early peak of gadolinium concentration (GD), suggestive of appropriate selection of arterial flow.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4499543&req=5

Figure 1: Selection of arterial input function (AIF) for analysis of permeability parameters.A. Region of interest was set at region of left cervical internal carotid artery (green color). Venous flow is depicted in blue. B. Time-concentration of gadolinium curve showed rapid upslope and early peak of gadolinium concentration (GD), suggestive of appropriate selection of arterial flow.
Mentions: Permeability parameters were calculated by off-line PRIDE tools provided by Philips Medical Systems (Best, The Netherlands), which is based on the pharmacokinetic model of Tofts et al. (31). The two compartment model of Tofts assumes intravascular and extravascular extracellular spaces, which are divided by the BBB. The degree of contrast leakage from the intravascular space to the extravascular extracellular space is referred to as Ktrans. The volume fraction of the extravascular extracellular space is referred to as ve. The volume fraction of plasma space is referred to as vp. Those permeability parameters were calculated by means of iteration between time-intensity curves of the artery and tissue in assumption of the Tofts model (2731). Arterial input function was measured at the area of left internal carotid artery (Fig. 1A) and its time-concentration curve was checked (Fig. 1B). Because extravasation of Evans blue was prominent near the slices of Bregma-1.60 mm, they were targeted for analysis. Briefly, post-processing consisted of motion correction of pixels from dynamic images, T1-mapping using different flip angles (5° and 15°), co-registration of pixels on the T1-map, arterial input function estimation, and pharmacokinetic modeling. All these processes were automatically performed by PRIDE tools. Different regions of interest (ROIs) were placed in the cortex and basal ganglia in the ipsilateral and contralateral hemispheres of transient MCA occlusion. Therefore, four different ROIs were drawn per rat. Then, the three types of permeability parameters (Ktrans, ve, and vp) were calculated on each ROI.

Bottom Line: Sprague-Dawley rats (n = 13) with transient middle cerebral artery occlusion were imaged using a 3-tesla MRI with an 8-channel wrist coil.All permeability parameters (K(trans), ve, and vp) showed a linear correlation with extravasation of Evans blue.Among them, K(trans) showed highest values of both the correlation coefficient and the coefficient of determination (0.687 and 0.473 respectively, p < 0.001).

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology, College of Medicine, The Catholic University of Korea, Seoul 137-701, Korea.

ABSTRACT

Objective: The purpose of this study was to correlate permeability parameters measured with dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) using a clinical 3-tesla scanner with extravasation of Evans blue in a rat model with transient cerebral ischemia.

Materials and methods: Sprague-Dawley rats (n = 13) with transient middle cerebral artery occlusion were imaged using a 3-tesla MRI with an 8-channel wrist coil. DCE-MRI was performed 12 hours, 18 hours, and 36 hours after reperfusion. Permeability parameters (K(trans), ve, and vp) from DCE-MRI were calculated. Evans blue was injected after DCE-MRI and extravasation of Evans blue was correlated as a reference with the integrity of the blood-brain barrier. Correlation analysis was performed between permeability parameters and the extravasation of Evans blue.

Results: All permeability parameters (K(trans), ve, and vp) showed a linear correlation with extravasation of Evans blue. Among them, K(trans) showed highest values of both the correlation coefficient and the coefficient of determination (0.687 and 0.473 respectively, p < 0.001).

Conclusion: Permeability parameters obtained by DCE-MRI at 3-T are well-correlated with Evans blue extravasation, and K(trans) shows the strongest correlation among the tested parameters.

No MeSH data available.


Related in: MedlinePlus