Magnetic resonance imaging measurements and clinical changes accompanying transtentorial and foramen magnum brain herniation

摘要: Current concepts of brain herniation have depended largely on correlating clinical signs and symptoms with indirect radiographic studies the results postmortem neuropathology. This article describes measurements midsagittal magnetic resonance imaging (MRI) scans that distinctly define normal abnormal rostral-caudal relationships between diencephalic-mesencephalic junction plane tentorial incisura, herein termed incisural line. We similarly provide quantitative MRI scan relating cerebellum foramen magnum, magnum Measurements from 156 63 coronal performed 123 adults, placed iter aqueduct 0.2 +/- 0.8 mm (mean SD) below line cerebellar tonsils 0.1 2.1 Defining 2 SD these norms as abnormal, 23 patients intracranial mass or obstructive lesions showed 4 distinct patterns herniation, i.e., upward downward transtentorial shift without accompanying tonsillar herniation. Five posterior fossa masses demonstrated displacement above incisura ranging 1.6 to 6.3 mm. Eighteen supratentorial 2.0 11.0 incisura. Two-thirds one-half those had concurrent In acute illnesses, changes anticipated confirmed chronic cases, correlated less well, sometimes revealing major degrees anatomical well in advance abnormalities.