Article
Size variability of the perihemorrhagic zone in patients undergoing surgical evacuation of lobar intracerebral hemorrhage – A perfusion-CT study
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Published: | May 21, 2013 |
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Objective: The perihemorrhagic zone in patients with spontaneous putaminal or thalamic intracerebral hemorrhage (SICH) is usually assumed to be size steady, i.e. 1 cm. However, in a cohort of patients suffering from lobar SICH, we previously reported a new definition of the PHZ using a mathematically, Perfusion-CT (PCT) derived approach. Therefore, we investigated the size variability of the PHZ in relation to hematoma volume and treatment using the PCT imaging in a previously reported cohort of patients suffering from lobar SICH.
Method: 20 patients who underwent surgery to remove a lobar SICH were scanned before and after surgery using PCT mapping. Mean transit time (MTT), time to peak of the residue function (Tmax), cerebral blood volume (CBV) and cerebral blood flow (CBF) were measured based on the 360 degree cortical banding method and singular-value decomposition. The PHZ was defined as such: Tmax deviation of more than twice the standard deviation of mean Tmax values in a healthy contralateral mirrored zone. In the cortical band the arc length, i.e. the PHZ, was calculated around the hematoma before and after surgery.
Results: Mean Hematoma volume was 67.81 ml (± 36.87) and correlated positively with the size of the PHZ (p = 0.011, R2 = 0.310). Mean hematoma volume was reduced to 8.04 ml (± 13.13) by surgical evacuation. A paired t-test showed a significant reduction of the PHZ from 6.51 cm (± 2.0) to 0.85 cm (± 1.25) (p < 0.001) after surgery.
Conclusions: Our findings illustrate that the size of the PHZ in patients with lobar SICH was distinctly greater than in previous reports on putaminal or thalamic SICH and related to surgical evacuation. This difference between lobar and putaminal SICH is most likely originated in the increased microcirculatory impairment in the presence of larger hematomas and their improvement following surgical treatment. If validated in a larger patient collective, these findings may have new implications on future perfusion studies on the PHZ in lobar SICH, especially in the context of the course of cerebral perfusion following treatment and throughout time.