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Usefulness of 99mTc-ECD brain SPECT with voxel-based analysis in evaluation of perfusion changes early after carotid endarterectomy.

Nocuń A, Wilczyński M, Wroński J, Chrapko B - Med. Sci. Monit. (2011)

Bottom Line: In patients with preoperative ipsilateral hypoperfusion and perfusion increase after CEA, AI correlated significantly with RD (r=0.48, p=0.04).Our results suggest that perfusion increase 3-5 days after CEA is higher in patients with greater ipsilateral asymmetry index.Evaluation of preoperative AI may help to identify patients in whom rapid reperfusion is more likely.

View Article: PubMed Central - PubMed

Affiliation: Department of Nuclear Medicine, Medical University of Lublin, Lublin, Poland. ampolak@o2

ABSTRACT

Background: Association between preoperative perfusion pattern and reperfusion after carotid endarterectomy (CEA) is an important yet unexplored topic. Therefore, the aim of our study was to determine whether 99mTc-ECD single-photon emission computed tomography (SPECT) performed before carotid endarterectomy in patients with internal carotid artery (ICA) stenosis may be helpful in predicting early perfusion changes after revascularization.

Material/methods: The examined group consisted of 30 patients (mean age 67.4±9.6 years) with ICA stenosis who underwent CEA. Infarction was demonstrated on computed tomography (CT) in 12 cases. Brain perfusion SPECT was performed 1-3 days before CEA and 3-5 days after the surgery. Voxel-based analysis was carried out with Brain SPECT Quantification software. For evaluation of preoperative interhemispheric asymmetry of perfusion, the percentage asymmetry index (AI) was calculated. For comparison of perfusion before and after CEA, the percentage relative difference (RD) was computed.

Results: Before CEA, cerebral hypoperfusion was seen in 26 cases, including 15 participants with normal CT. After CEA, the following changes of perfusion were observed: perfusion increase n=18 (ipsilateral and bilateral), deterioration n=1, mixed patterns n=2, no change n=9. In patients with preoperative ipsilateral hypoperfusion and perfusion increase after CEA, AI correlated significantly with RD (r=0.48, p=0.04).

Conclusions: Our results suggest that perfusion increase 3-5 days after CEA is higher in patients with greater ipsilateral asymmetry index. Evaluation of preoperative AI may help to identify patients in whom rapid reperfusion is more likely.

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Related in: MedlinePlus

Example of voxel-based analysis of preoperative ipsilateral hypoperfusion (right hemisphere) and perfusion increase after carotid endarterectomy in patient no 9: (A) preoperative SPECT, (B) postoperative SPECT, (C) cluster analysis of preoperative SPECT (asymmetry index=23.7%, cluster volume=233 ml), (D) cluster analysis of postoperative SPECT (relative difference=18.5%:, cluster volume=175 ml).
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f2-medscimonit-17-5-cr297: Example of voxel-based analysis of preoperative ipsilateral hypoperfusion (right hemisphere) and perfusion increase after carotid endarterectomy in patient no 9: (A) preoperative SPECT, (B) postoperative SPECT, (C) cluster analysis of preoperative SPECT (asymmetry index=23.7%, cluster volume=233 ml), (D) cluster analysis of postoperative SPECT (relative difference=18.5%:, cluster volume=175 ml).

Mentions: where C and I represent counts in the contralateral and ipsilateral symmetrical voxels, respectively. This step was followed by cluster analysis. Abnormalities were discerned by a 3D region-growing algorithm which compares voxels in the image to the corresponding limits (cut-off values). These values can be set by the user in a program configuration. Contiguous regions are identified for which these conditions are met. Clusters of abnormal regions are listed and reported with respect to the absolute cluster size in ml-cluster volume (CV), severity (the mean percentage of AI in the cluster region) and location. The cut-off values were set as follows: AI higher than 10% in a cluster volume greater than 10 ml. In the present study, AI is always a positive number, expressing the severity of ipsilateral or contralateral hypoperfusion in relation to the opposite hemisphere. Cluster analysis of hypoperfused regions in both hemispheres is presented in Figure 1 (B, D) and in the ipsilateral hemisphere in Figure 2 (C).


Usefulness of 99mTc-ECD brain SPECT with voxel-based analysis in evaluation of perfusion changes early after carotid endarterectomy.

Nocuń A, Wilczyński M, Wroński J, Chrapko B - Med. Sci. Monit. (2011)

Example of voxel-based analysis of preoperative ipsilateral hypoperfusion (right hemisphere) and perfusion increase after carotid endarterectomy in patient no 9: (A) preoperative SPECT, (B) postoperative SPECT, (C) cluster analysis of preoperative SPECT (asymmetry index=23.7%, cluster volume=233 ml), (D) cluster analysis of postoperative SPECT (relative difference=18.5%:, cluster volume=175 ml).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3539580&req=5

f2-medscimonit-17-5-cr297: Example of voxel-based analysis of preoperative ipsilateral hypoperfusion (right hemisphere) and perfusion increase after carotid endarterectomy in patient no 9: (A) preoperative SPECT, (B) postoperative SPECT, (C) cluster analysis of preoperative SPECT (asymmetry index=23.7%, cluster volume=233 ml), (D) cluster analysis of postoperative SPECT (relative difference=18.5%:, cluster volume=175 ml).
Mentions: where C and I represent counts in the contralateral and ipsilateral symmetrical voxels, respectively. This step was followed by cluster analysis. Abnormalities were discerned by a 3D region-growing algorithm which compares voxels in the image to the corresponding limits (cut-off values). These values can be set by the user in a program configuration. Contiguous regions are identified for which these conditions are met. Clusters of abnormal regions are listed and reported with respect to the absolute cluster size in ml-cluster volume (CV), severity (the mean percentage of AI in the cluster region) and location. The cut-off values were set as follows: AI higher than 10% in a cluster volume greater than 10 ml. In the present study, AI is always a positive number, expressing the severity of ipsilateral or contralateral hypoperfusion in relation to the opposite hemisphere. Cluster analysis of hypoperfused regions in both hemispheres is presented in Figure 1 (B, D) and in the ipsilateral hemisphere in Figure 2 (C).

Bottom Line: In patients with preoperative ipsilateral hypoperfusion and perfusion increase after CEA, AI correlated significantly with RD (r=0.48, p=0.04).Our results suggest that perfusion increase 3-5 days after CEA is higher in patients with greater ipsilateral asymmetry index.Evaluation of preoperative AI may help to identify patients in whom rapid reperfusion is more likely.

View Article: PubMed Central - PubMed

Affiliation: Department of Nuclear Medicine, Medical University of Lublin, Lublin, Poland. ampolak@o2

ABSTRACT

Background: Association between preoperative perfusion pattern and reperfusion after carotid endarterectomy (CEA) is an important yet unexplored topic. Therefore, the aim of our study was to determine whether 99mTc-ECD single-photon emission computed tomography (SPECT) performed before carotid endarterectomy in patients with internal carotid artery (ICA) stenosis may be helpful in predicting early perfusion changes after revascularization.

Material/methods: The examined group consisted of 30 patients (mean age 67.4±9.6 years) with ICA stenosis who underwent CEA. Infarction was demonstrated on computed tomography (CT) in 12 cases. Brain perfusion SPECT was performed 1-3 days before CEA and 3-5 days after the surgery. Voxel-based analysis was carried out with Brain SPECT Quantification software. For evaluation of preoperative interhemispheric asymmetry of perfusion, the percentage asymmetry index (AI) was calculated. For comparison of perfusion before and after CEA, the percentage relative difference (RD) was computed.

Results: Before CEA, cerebral hypoperfusion was seen in 26 cases, including 15 participants with normal CT. After CEA, the following changes of perfusion were observed: perfusion increase n=18 (ipsilateral and bilateral), deterioration n=1, mixed patterns n=2, no change n=9. In patients with preoperative ipsilateral hypoperfusion and perfusion increase after CEA, AI correlated significantly with RD (r=0.48, p=0.04).

Conclusions: Our results suggest that perfusion increase 3-5 days after CEA is higher in patients with greater ipsilateral asymmetry index. Evaluation of preoperative AI may help to identify patients in whom rapid reperfusion is more likely.

Show MeSH
Related in: MedlinePlus