title: Increased density of tentorium and falx: a false positive CT sign of subarachnoid hemorrhage.
abstract: Noncontrast computed tomographic (CT) findings in 10 patients with profound brain swelling or a mass effect revealed a high density of the falx and tentorium and thus suggested subarachnoid hemorrhage. Postmortem examinations performed shortly after the CT scans demonstrated no subarachnoid blood. A review of 100 CT scans drawn at random was carried out to assess the frequency of a hyperdense, noncalcified falx in the same population and failed to demonstrate this finding. Therefore, in the presence of profound brain swelling or a mass effect, factors other than subarachnoid hemorrhage may be responsible for increased density of the falx and tentorium on cranial CT head scans.
mesh_terms: D000328:Adult; D000368:Aged; D001344:Autopsy; D001929:Brain Edema / Q000000981:diagnostic imaging; D001932:Brain Neoplasms / Q000000981:diagnostic imaging; D002531:Cerebellum / Q000000981:diagnostic imaging*; D002544:Cerebral Infarction / Q000000981:diagnostic imaging; D003937:Diagnosis, Differential; D004388:Dura Mater / Q000000981:diagnostic imaging*; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D007427:Intracranial Pressure; D008297:Male; D008875:Middle Aged; D013345:Subarachnoid Hemorrhage / Q000000981:diagnostic imaging* / Q000473:pathology; D014057:Tomography, X-Ray Computed