It has been noted that a low degree of ectopia of the cerebellar tonsils on MR is of questionable significance. We measured the position of the cerebellar tonsils with respect to the inferior aspect of the foramen magnum in 200 normal patients and in 25 patients with a firm diagnosis of Chiari I malformation. In the normal group, the mean position of the tonsils was 1 mm above the foramen magnu...

The treatment of dural arteriovenous fistulas (DAVFs) at the foramen magnum remains controversial by reason that DAVFs appearing from the foramen magnum represent only a minority of spinal DAVFs. We present our treatment for an asymptomatic patient suffering from a foramen magnum DAVF. A 53-year-old man presented to our hospital with the complaint of a floating sensation. Although there was no ...

The anterior position of the human foramen magnum is often explained as an adaptation for maintaining balance of the head atop the cervical vertebral column during bipedalism and the assumption of orthograde trunk postures. Accordingly, the relative placement of the foramen magnum on the basicranium has been used to infer bipedal locomotion and hominin status for a number of Mio-Pliocene fossil...

BACKGROUND AND PURPOSE Previous studies have quantified CSF flow in patients with Chiari I at the foramen magnum with single-axial or single-sagittal PCMR. The goal of this study was to measure CSF velocities at multiple cervical spinal levels in patients with Chiari I malformation. MATERIALS AND METHODS In a patient registry, consecutive patients without surgery who had PCMR flow images in 5...

Histologic classification of 120 meningiomas was correlated with their proliferative fraction and DNA ploidy using immunohistochemistry and flow cytometry to differentiate histologically atypical meningiomas from benign ones. Histologically, the 120 meningiomas included 101 benign (43 meningotheliomatous, 40 transitional, 11 fibroblastic, 2 secretory, 2 microcystic, 2 angiomatous, and 1 psammom...

UNLABELLED Meningiomas are the most common non-glial tumour of the central nervous system (CNS). There are a number of characteristic imaging features of meningiomas on magnetic resonance imaging (MRI) that allow an accurate diagnosis, however there are a number of atypical features that may be diagnostically challenging. Furthermore, a number of other neoplastic and non-neoplastic conditions m...

Usually considered benign tumors, meningiomas can display aggressive behavior characterized by multiple recurrences and invasion of the brain, dura, and adjacent bone. The aggressive or malignant phenotype is difficult to characterize due to the broad spectrum of behaviors exhibited by meningiomas. Recent classification schemes based on features of anaplasia rather than histopathology have been...

Meningiomas are classified into three groups (benign, atypical, and anaplastic) based on morphologic characteristics. Atypical meningiomas, which are WHO grade 2 tumors, and anaplastic meningiomas, which are WHO grade 3 tumors, exhibit an increased risk of recurrence and premature death compared with benign WHO grade 1 tumors. Although atypical and anaplastic meningiomas account for <10% of all...

OBJECTIVE The female preponderance of meningiomas may reflect hormonal influences on meningioma growth. We hypothesized that because obesity affects male steroid hormone synthesis, male patients with meningiomas might exhibit a high obesity rate, which, in turn, might increase their frequency of postoperative complications. METHODS We retrospectively reviewed male patients who underwent crani...

OBJECTIVE To evaluate progesterone and estrogen receptor expression in meningiomas of the CNS in dogs and cats. ANIMAL 8 dogs (1 of which was treated with gestrinone) and 5 cats with intracranial meningiomas and 2 dogs with spinal cord meningiomas; tissue samples were also obtained from 1 clinically normal dog and 1 clinically normal cat. PROCEDURE Meningioma tissue was obtained during surg...