Prediction of Borderzone Infarction by CTA in Patients Undergoing Carotid Embolization for Carotid Blowout

Abstract

Background and purpose: Permanent common carotid artery and/or ICA occlusion is an effective treatment for carotid blowout syndrome. Besides postoperative thromboembolic infarction, permanent common carotid artery and/or ICA occlusion may cause borderzone infarction when the collateral flow to the deprived brain territory is inadequate. In this study, we aimed to test the predictive value of CTA for post-permanent common carotid artery and/or ICA occlusion borderzone infarction in patients with carotid blowout syndrome.

Materials and methods: In this retrospective study, we included 31 patients undergoing unilateral permanent common carotid artery and/or ICA occlusion for carotid blowout syndrome between May 2009 and December 2016. The vascular diameter of the circle of Willis was evaluated using preprocedural CTA, and the risk of borderzone infarction was graded as very high risk, high risk, intermediate risk, low risk, and very low risk.

Results: The performance of readers' consensus on CTA for predicting borderzone infarction was excellent, with an area under receiver operating characteristic curve of 0.938 (95% confidence interval, 0.85-1.00). We defined very high risk, high risk, and intermediate risk as positive for borderzone infarction, the sensitivity, specificity, positive predictive value, and negative predictive value of CTA for borderzone infarction were 100% (7/7), 62.5% (15/24), 43.8% (7/16), and 100% (15/15), respectively. The interobserver reliability was excellent (κ = 0.807). No significant difference in the receiver operating characteristic curves was found between the 2 readers (P = .114).

Conclusions: CTA can be used to predict borderzone infarction after permanent common carotid artery and/or ICA occlusion by measuring the collateral vessels of the circle of Willis.

Fig 1.

A 33-year-old man with nasopharyngeal carcinoma and left ICA blowout. A, No right A1 segment is detected on the coronal MIP (5 mm) image (white arrow). B, Only a hair-thin PcomA is detected on the axial MIP (5 mm) image. C, The narrowest portion of the anterior and posterior collateral vessels is aplastic, and the patient is grouped as very high risk. The recruited collateral flows after PCO are indicated by gray arrows. D, Diffusion-weighted imaging shows left borderzone infarction and bilateral anterior cerebral artery thromboembolic infarction on the same day after left ICA embolization.

Fig 2.

This 74-year-old man with nasopharyngeal carcinoma presented with massive hematemesis and epistaxis. A, Faint opacification of the AcomA (white arrow) is shown on the oblique MIP image (7 mm), which is hypoplastic. The target of embolization is the right ICA (black arrow) due to an ICA pseudoaneurysm (not shown). B, No right PcomA is detected on the axial MIP image (7 mm). C, This patient is interpreted as high risk because only 1 hypoplastic AcomA supplies the collateral flow (gray arrows). D, Right borderzone infarction and tiny left embolic infarctions developed 5 days after right ICA embolization (shown on diffusion-weighted imaging).

Fig 3.

Images in a 36-year-old man with massive bleeding from a protruding tumor. A, Oblique MIP image (7 mm) shows that the AcomA (white arrow) diameter is >50% of the ipsilateral A2 artery (PCO side, hollow arrow). B, The left PcomA on the axial MIP image (5 mm) is aplastic. C, The patient is interpreted as low risk. The recruited collateral flows after PCO are indicated by gray arrows. D, Intraprocedural angiography shows irregular narrowing of the diseased left ICA (black arrow). No neurologic deficit was detected after left PCO.

Fig 4.

A 52-year-old man with hypopharyngeal cancer and bleeding from the exposed left carotid artery. A, Axial MIP image (7 mm) shows a well-opacified AcomA (white arrow), which is >50% of the ipsilateral (PCO side) A2 segment (not shown). B, An axial MIP image (7 mm) reveals the left PcomA (black arrow), which is considered patent. C, The patient is considered very low risk. The recruited collateral flows after PCO are indicated by gray arrows. D, No cerebral infarction was found on brain CT 14 days after the left ICA embolization.