Mechanical thrombectomy has become the standard of care for patients with acute ischemic stroke secondary to a large vessel occlusion, but despite the continuous improvements in materials and techniques, posttreatment hemorrhage still represents a potentially devastating complication. The reason for this resides in the fact that besides bleedings secondary to intraprocedural vessel rupture, whose prevalence has significantly dropped off (thanks to improvements in materials), in most cases, hemorrhagic complications represent the consequence of a combination of increased vessel wall fragility within the ischemic territory and a postrevascularization increase of arterial pressure in the above-mentioned vessels.
We were aware that, thanks to its 3-material decomposition capability, dual-energy CT enables accurate characterization of the parenchymal hyperdensities that often can be observed on postprocedural CT, differentiating iodine extravasation from blood. Iodine extravasation represents the direct consequence of BBB disruption, secondary to inflammatory and necrotic changes in the ischemic territory. We postulated that the greater the BBB damage, the higher the hemorrhagic risk.
Therefore, we decided to consider maximum iodine concentration, which can be easily estimated on dual-energy CT images using commercially available software, as a biomarker for vessel wall damage. The results of the study confirmed our hypothesis; the prevalence of hemorrhagic complications is significantly correlated with the presence and the maximum concentration of iodine extravasation. In our series, a cutoff value of 1.35 mg/mL enabled us to identify patients developing hemorrhagic complications with 100% sensitivity and 67.5% specificity.
Our publication and its potential clinical implications raised a lot of interest and curiosity among the neurologists of our institution and among the colleagues encountered at radiologic meetings. The results of our study can be easily used in everyday practice for better tailoring postthrombectomy care.
In particular, arterial pressure should be more strictly monitored in patients with a high concentration of iodine extravasation and the potential benefit of antiplatelet drug administration should be accurately evaluated in this group of patients, given the increased hemorrhagic risk.