[Peculiar computed tomographic images after intracranial use of microfibrillar collagen hemostat: report of three cases].

After the intracranial application of microfibrillar collagen hemostat (Avitene), CT revealed contrast enhancement suggestive of brain abscess or residual or recurrent tumor in three patients. The first case was a 22-year-old male with left ventricular oligodendroglioma. At operation Avitene was applied to the ventricular wall and incised frontal lobe. Two months after the operation CT revealed ring enhancement at the left frontal lobe and ventricular enlargement. Craniotomy was performed again. Histological examination, however, revealed no recurrent tumor but residual Avitene and granulation. The second case was a 57-year-old female with left parietal glioblastoma multiforme. At operation Avitene was applied to the tumor cavity. Two months after the operation CT showed ring enhancement and craniotomy was performed again. Histological examination revealed residual Avitene and necrotic tissue. Five months after the first operation, craniotomy was performed for the third time, because recurrence was suspected after a CT scan. Histological examination revealed recurrent tumor and residual Avitene. The third case was a 19-year-old male with left frontal astrocytoma. Two months after the operation when Avitene was used for hemostasis, marked ring enhancement was observed. Five months after the operation, however, enhancement in CT was weak. The CT findings in these patients were characterized by the abnormally long duration of enhancement (five months) and by enhancement more marked two to three months after the operation than immediately after it. Based on these findings brain abscess or residual or recurrent tumor rather than normal healing was more suspect as the cause of this phenomenon. Brain abscess was ruled out, because the peripheral leukocyte count, erythrocyte sedimentation rate, CRP, etc. were normal.(ABSTRACT TRUNCATED AT 250 WORDS)