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Precise Characterization of the Penumbra Revealed by MRI: A Modified Photothrombotic Stroke Model Study.

Qian C, Li PC, Jiao Y, Yao HH, Chen YC, Yang J, Ding J, Yang XY, Teng GJ - PLoS ONE (2016)

Bottom Line: One hour after occlusion, the low perfusion areas on the perfusion-weighted imaging interlaced with the hypointense areas on the apparent diffusion coefficient map, demonstrating that the penumbra was located both surrounding and inside the lesions.This phenomenon was subsequently confirmed by the c-fos and heart shock protein 90 staining.At early stages, the lesions were clearly identified on the apparent diffusion coefficient map; the volumes of the lesions on the diffusion-weighted imaging and T2-weighted imaging did not reach a maximum until 12 hours.

View Article: PubMed Central - PubMed

Affiliation: Jiangsu Key Laboratory of Molecular and Functional Imaging, Department of Radiology, Zhongda Hospital, Medical School, Southeast University, Nanjing, China.

ABSTRACT

Aims: To precisely characterize the penumbra by MRI based on a modified photothrombotic stroke mouse model.

Methods: The proximal middle cerebral artery was occluded by a convenient laser system in conjunction with an intravenous injection of Rose Bengal in mice. And the suture MCAO model was performed in seven mice as a comparison of the reproducibility. One hour after occlusion, the penumbra was defined in six random photothrombotic stroke mice by mismatch between perfusion-weighted imaging and the apparent diffusion coefficient map on a home-made workstation. After imaging, three random mice of them were chosen to perform the reperfusion surgery. And the other three mice were sacrificed to stain for several potential penumbra markers, such as c-fos and heart shock protein 90. In the remaining mice, the evolution of the lesions was detected on the apparent diffusion coefficient map, diffusion-weighted imaging and T2-weighted imaging at 1, 3, 6, 12 and 24 hours. After evaluating the neurological deficit scores, the brains were sectioned and stained by triphenyltetrazolium chloride and Nissl.

Results: The mice subjected to photothrombosis showed significant behavioral deficits. One hour after occlusion, the low perfusion areas on the perfusion-weighted imaging interlaced with the hypointense areas on the apparent diffusion coefficient map, demonstrating that the penumbra was located both surrounding and inside the lesions. This phenomenon was subsequently confirmed by the c-fos and heart shock protein 90 staining. The final T2-weighted images of the mice subjected to the reperfusion surgery were also consistent with the penumbra images at one hour. At early stages, the lesions were clearly identified on the apparent diffusion coefficient map; the volumes of the lesions on the diffusion-weighted imaging and T2-weighted imaging did not reach a maximum until 12 hours. The coefficient of variation (CV) of the final lesions in the photothrombotic stroke mice was 21.7% (0.08 of 0.37) on T2-weighted imaging and 27.8% (0.10 of 0.35) on triphenyltetrazolium chloride, representing a high reproducibility (n = 7). While the CV of the lesions in the MCAO stroke mice was only 70% (0.24 of 0.34, n = 4).

Conclusions: This study has provided a precise imaging definition of the penumbra based on a reproducible photothrombotic stroke mouse model.

No MeSH data available.


Related in: MedlinePlus

The evolution of the infarct volume on MRI.A) The brain lesions were detected by T2WI, ADC map and DWI at different time points. The curving midlines (white arrows) indicate a severe brain edema. B) The ADC map showed relatively larger lesion volumes at 1 hour (*p<0.05) versus DWI, 3 hours and 6 hours (*p<0.05), and versus T2WI. The relative lesion volumes on DWI and T2WI reached a maximum and matched well with those on ADC map at 12 hours (p>0.05), On T2WI, the lesion volumes at 12 and 24 hours were larger (#p<0.05) versus that at 3 hours; while on DWI the volumes at 12 and 24 hours were larger (#p<0.05) versus that at 1 hour.
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pone.0153756.g002: The evolution of the infarct volume on MRI.A) The brain lesions were detected by T2WI, ADC map and DWI at different time points. The curving midlines (white arrows) indicate a severe brain edema. B) The ADC map showed relatively larger lesion volumes at 1 hour (*p<0.05) versus DWI, 3 hours and 6 hours (*p<0.05), and versus T2WI. The relative lesion volumes on DWI and T2WI reached a maximum and matched well with those on ADC map at 12 hours (p>0.05), On T2WI, the lesion volumes at 12 and 24 hours were larger (#p<0.05) versus that at 3 hours; while on DWI the volumes at 12 and 24 hours were larger (#p<0.05) versus that at 1 hour.

Mentions: The ischemic lesions in the photothrombotic stroke group depicted on different MRI sequences spread from the ventral part of the basal ganglia to the entire basal ganglia and ipsilateral cortex with time. The degree of brain edema became more and more severe, reflected by a shift of the midline (white arrows, Fig 2A). At one hour after MCA occlusion, only the ADC map could display distinct lesions. Indeed, the T2WI detected few significant abnormal signals at that time. At 3 and 6 hours, the ADC map still showed larger relative lesion volumes than T2WI (p<0.05). Meanwhile, although there was no significant statistical differences, the rVL on DWI was somewhat smaller than that on the ADC map. The rVL on DWI and T2WI reached a maximum and matched well with that on the ADC map at 12 hours. As shown in Fig 2B, the rVL on DWI at 12 and 24 hours were significantly larger than that at 1 hour, and the rVL on T2WI at 12 and 24 hours were also significantly larger than that at 3 hours (p< 0.05). However, the rVL on ADC map at different time points remained consistent (0.42±0.07, 0.37±0.05, 0.40±0.08, 0.41±0.08, 0.41±0.06 at 1,3,6,12,24 hours, respectively, p> 0.05).


Precise Characterization of the Penumbra Revealed by MRI: A Modified Photothrombotic Stroke Model Study.

Qian C, Li PC, Jiao Y, Yao HH, Chen YC, Yang J, Ding J, Yang XY, Teng GJ - PLoS ONE (2016)

The evolution of the infarct volume on MRI.A) The brain lesions were detected by T2WI, ADC map and DWI at different time points. The curving midlines (white arrows) indicate a severe brain edema. B) The ADC map showed relatively larger lesion volumes at 1 hour (*p<0.05) versus DWI, 3 hours and 6 hours (*p<0.05), and versus T2WI. The relative lesion volumes on DWI and T2WI reached a maximum and matched well with those on ADC map at 12 hours (p>0.05), On T2WI, the lesion volumes at 12 and 24 hours were larger (#p<0.05) versus that at 3 hours; while on DWI the volumes at 12 and 24 hours were larger (#p<0.05) versus that at 1 hour.
© Copyright Policy
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4836676&req=5

pone.0153756.g002: The evolution of the infarct volume on MRI.A) The brain lesions were detected by T2WI, ADC map and DWI at different time points. The curving midlines (white arrows) indicate a severe brain edema. B) The ADC map showed relatively larger lesion volumes at 1 hour (*p<0.05) versus DWI, 3 hours and 6 hours (*p<0.05), and versus T2WI. The relative lesion volumes on DWI and T2WI reached a maximum and matched well with those on ADC map at 12 hours (p>0.05), On T2WI, the lesion volumes at 12 and 24 hours were larger (#p<0.05) versus that at 3 hours; while on DWI the volumes at 12 and 24 hours were larger (#p<0.05) versus that at 1 hour.
Mentions: The ischemic lesions in the photothrombotic stroke group depicted on different MRI sequences spread from the ventral part of the basal ganglia to the entire basal ganglia and ipsilateral cortex with time. The degree of brain edema became more and more severe, reflected by a shift of the midline (white arrows, Fig 2A). At one hour after MCA occlusion, only the ADC map could display distinct lesions. Indeed, the T2WI detected few significant abnormal signals at that time. At 3 and 6 hours, the ADC map still showed larger relative lesion volumes than T2WI (p<0.05). Meanwhile, although there was no significant statistical differences, the rVL on DWI was somewhat smaller than that on the ADC map. The rVL on DWI and T2WI reached a maximum and matched well with that on the ADC map at 12 hours. As shown in Fig 2B, the rVL on DWI at 12 and 24 hours were significantly larger than that at 1 hour, and the rVL on T2WI at 12 and 24 hours were also significantly larger than that at 3 hours (p< 0.05). However, the rVL on ADC map at different time points remained consistent (0.42±0.07, 0.37±0.05, 0.40±0.08, 0.41±0.08, 0.41±0.06 at 1,3,6,12,24 hours, respectively, p> 0.05).

Bottom Line: One hour after occlusion, the low perfusion areas on the perfusion-weighted imaging interlaced with the hypointense areas on the apparent diffusion coefficient map, demonstrating that the penumbra was located both surrounding and inside the lesions.This phenomenon was subsequently confirmed by the c-fos and heart shock protein 90 staining.At early stages, the lesions were clearly identified on the apparent diffusion coefficient map; the volumes of the lesions on the diffusion-weighted imaging and T2-weighted imaging did not reach a maximum until 12 hours.

View Article: PubMed Central - PubMed

Affiliation: Jiangsu Key Laboratory of Molecular and Functional Imaging, Department of Radiology, Zhongda Hospital, Medical School, Southeast University, Nanjing, China.

ABSTRACT

Aims: To precisely characterize the penumbra by MRI based on a modified photothrombotic stroke mouse model.

Methods: The proximal middle cerebral artery was occluded by a convenient laser system in conjunction with an intravenous injection of Rose Bengal in mice. And the suture MCAO model was performed in seven mice as a comparison of the reproducibility. One hour after occlusion, the penumbra was defined in six random photothrombotic stroke mice by mismatch between perfusion-weighted imaging and the apparent diffusion coefficient map on a home-made workstation. After imaging, three random mice of them were chosen to perform the reperfusion surgery. And the other three mice were sacrificed to stain for several potential penumbra markers, such as c-fos and heart shock protein 90. In the remaining mice, the evolution of the lesions was detected on the apparent diffusion coefficient map, diffusion-weighted imaging and T2-weighted imaging at 1, 3, 6, 12 and 24 hours. After evaluating the neurological deficit scores, the brains were sectioned and stained by triphenyltetrazolium chloride and Nissl.

Results: The mice subjected to photothrombosis showed significant behavioral deficits. One hour after occlusion, the low perfusion areas on the perfusion-weighted imaging interlaced with the hypointense areas on the apparent diffusion coefficient map, demonstrating that the penumbra was located both surrounding and inside the lesions. This phenomenon was subsequently confirmed by the c-fos and heart shock protein 90 staining. The final T2-weighted images of the mice subjected to the reperfusion surgery were also consistent with the penumbra images at one hour. At early stages, the lesions were clearly identified on the apparent diffusion coefficient map; the volumes of the lesions on the diffusion-weighted imaging and T2-weighted imaging did not reach a maximum until 12 hours. The coefficient of variation (CV) of the final lesions in the photothrombotic stroke mice was 21.7% (0.08 of 0.37) on T2-weighted imaging and 27.8% (0.10 of 0.35) on triphenyltetrazolium chloride, representing a high reproducibility (n = 7). While the CV of the lesions in the MCAO stroke mice was only 70% (0.24 of 0.34, n = 4).

Conclusions: This study has provided a precise imaging definition of the penumbra based on a reproducible photothrombotic stroke mouse model.

No MeSH data available.


Related in: MedlinePlus