Hyperattenuated intracerebral lesions after mechanical recanalization in acute stroke

Abstract

Background and purpose: Following mechanical recanalization of an acute intracranial vessel occlusion, hyperattenuated lesions are frequently found on postinterventional cranial CT. They represent either blood or-more frequently-enhancement of contrast agent. Here, we aimed to evaluate the prognostic value of these hyperattenuated intracerebral lesions.

Materials and methods: One hundred one consecutive patients with acute stroke in the anterior circulation who underwent mechanical recanalization were included. Risk factors for hyperattenuated intracerebral lesions were assessed, and lesion volume was compared with the volume of final infarction. Clinical outcome and relative risk of secondary hemorrhage were determined in patients with and without any hyperattenuated lesions and compared.

Results: The frequency of hyperattenuated lesions was 84.2%. Risk factors for hyperattenuated lesions were female sex, higher NIHSS score on admission, and higher amount of contrast agent applied. On follow-up, 3 patients showed no infarction; 53 patients, an ischemic infarction; and 45 patients, a hemorrhagic infarction. In all except 1 case, final volume of infarction (median = 92.4 mL) exceeded the volume of hyperattenuated intracerebral lesions (median = 5.6 mL). Patients with hyperattenuated lesions were at a 4 times higher relative risk for hemorrhagic transformation but had no significantly worse clinical outcome.

Conclusions: Our data show that the extent of postinterventional hyperattenuated intracerebral lesions underestimates the volume of final infarction. Although hyperattenuated lesions indicate a higher risk of secondary hemorrhagic transformation, their presence seems not to be of any prognostic value regarding clinical outcome.

Fig 1.

Postinterventional CCT of 3 different patients with hyperattenuated lesions in the basal ganglia (A, arrows), cortex (B, arrows), and cortical sulci (C, arrows).

Fig 2.

Flow diagram of patient identification and imaging findings. HCLs indicate hyperattenuating intracerebral lesions; pCCT, postinterventional cranial CT; CE, contrast enhancement; HT, hemorrhagic transformation.

Fig 3.

A 47-year-old man with acute occlusion of the right MCA and mechanical recanalization. Postinterventional CCT (A) shows a hyperattenuated intracerebral lesion in the right putamen (thin arrow) and early signs of ischemic infarction in the right anterior insula (thick arrow). MR imaging (FLAIR in B, and T2* in C) 2 days following the event shows pure ischemic infarction in both localizations (right putamen and anterior insula; thin and thick arrows in B and C). Furthermore, MR imaging shows an intracerebral hematoma (PH1) in the right parieto-occipital lobe (arrowheads on B and C), where no hyperattenuated lesion was evident on postinterventional CCT. Clinical outcome of this patient was good (mRS 1).