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. 2025 May 26;167(1):155.
doi: 10.1007/s00701-025-06545-0.

Investigation of the hyperperfusion phenomenon following carotid artery stenting using preoperative computed tomography perfusion imaging

Hiroyuki Yamamoto  1 , Daisuke Maruyama  2 , Masataka Nanto  2 , Naoya Hashimoto  2
Affiliations

Investigation of the hyperperfusion phenomenon following carotid artery stenting using preoperative computed tomography perfusion imaging

Hiroyuki Yamamoto et al. Acta Neurochir (Wien). .

Abstract

Purpose: This study aimed to identify the most effective parameters of computed tomography perfusion imaging (CTP) using the Bayesian estimation to predict hyperperfusion phenomenon (HPP) risk after carotid artery stenting (CAS).

Methods: We retrospectively analyzed 46 patients who underwent CAS with preoperative CTP and preoperative and postoperative 123I-labeled N-isopropyl-p-iodoamphetamine (123I-IMP) single photon emission computed tomography (SPECT) at rest, between April 2019 and March 2024. Patients were categorized into the HPP and non-HPP groups based on the postoperative asymmetry index (AI) of cerebral blood flow (CBF) on 123I-IMP SPECT. Relative ratios of CBF, cerebral blood volume (CBV), mean transit time (MTT), and time-to-peak (TTP) were calculated from preoperative CTP and compared between the two groups. Correlations among each CTP parameter, preoperative AI, and postoperative AI were assessed. Receiver operating characteristic (ROC) analysis identified the most accurate CTP parameters for predicting HPP.

Results: HPP occurred in four patients, with one developing cerebral hemorrhage. Significant differences were observed between the HPP and non-HPP groups in CBV (p = 0.001), MTT (p = 0.003), and TTP ratio (p = 0.011), and preoperative AI (p = 0.021). Among the CTP parameters and preoperative AI, the CBV ratio showed a positive correlation with the postoperative AI (r = 0.63, p < 0.01). The CBV ratio demonstrated the highest area under the curve (AUC) for predicting HPP (AUC = 0.95). However, after Benjamini-Hochberg correction, statistical significance was lost (adjusted p = 0.07).

Conclusion: This study evaluated the predictive value of preoperative CTP using the Bayesian estimation method for identifying HPP risk after CAS. CBV ratio may serve as a potential parameter for predicting HPP.

Keywords: Carotid artery stenting; Computed tomography perfusion imaging; Hyperperfusion phenomenon; Hyperperfusion syndrome; Single photon emission computed topography.

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Conflict of interest statement

Declarations. Ethical approval: All procedures involving human participants performed in this study were in accordance with the ethical standards of the institutional committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards. This study was approved by the Ethics Committee of Kyoto Prefectural University of Medicine Hospital (Approval No: ERB-C- 2730). In conducting this research, we strictly adhered to the Personal Information Protection Law regarding the handling of personal information of the participants based on the Declarations of Helsinki. Informed consent: Informed consent for participation was obtained through an opt-out process due to the anonymity of data, as approved by the ethics committee. Consent to publish: The authors declare their consent for publication. Competing interests: The authors declare no competing interests.

Figures

Fig. 1
Fig. 1
Reconstructed maps of CTP and 123I-IMP SPECT brain imaging at rest (case 10: left carotid artery stenosis). Regions of interest were automatically determined using 3D-SRT software, which converts volume data of CTP and 123I-IMP SPECT at rest to 59 slices of 2-mm interval standardized images. In this figure, 4 representative slices of 59 slices in each map of CTP parameter and 123I-IMP SPECT at rest are presented. A: yellow-circled ROIs were used for calculation as ROIs in the MCA territory, B: cerebral blood flow (CBF), C: cerebral blood volume (CBV), D: mean transit time (MTT), E: time to peak (TTP), F: preoperative 123I-IMP SPECT at rest, G: postoperative 123I-IMP SPECT at rest. The patient developed HPP without cerebral hyperperfusion syndrome including cerebral hemorrhage after CAS
Fig. 2
Fig. 2
Imaging results of a 65-year-old man with a right carotid artery stenosis followed by intracerebral hemorrhage after CAS. Reconstructed maps of preoperative CTP showing a relatively decreased regional CBF (CBF ratio: 0.83) (A), increased regional CBV (CBV ratio: 1.24) (B), increased regional MTT (MTT ratio: 1.31) (C), and increased regional TTP (TTP ratio: 1.10) (D) in the right hemisphere. Preoperative 123I-IMP SPECT at rest showing decreased regional CBF (AI: 0.88) in the right hemisphere (E). Postoperative 123I-IMP SPECT at rest showing increased regional CBF (AI: 1.17) in the right hemisphere after CAS (F). The patient had cerebral hemorrhage in the ipsilateral basal ganglia on the postoperative day 3 after CAS (G)
Fig. 3
Fig. 3
Scatter plots showing the correlation between each CTP ratio and postoperative AI. Black hollow circles (○) indicate the cases without HPP. Black filled circles (●) indicate cases with HPP, and black triangles (▲) indicate cases with HPP followed by intracerebral hemorrhage after CAS. The black line in each plot shows the regression line. Dashed lines show thresholds of each CTP parameter and postoperative AI to distinguish patients with HPP from patients without HPP
Fig. 4
Fig. 4
Receiver operating characteristic curves of the CBF ratio, CBV ratio, MTT ratio, TTP ratio, and preoperative AI for the identification of patients at risk for HPP
See this image and copyright information in PMC

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