2024年7月19日 · Arachnoid granulations, also known as Pacchionian granulations, are projections of the arachnoid membrane (villi) into the dural sinuses that allow CSF to pass from the subarachnoid space into the venous system. They increase in size and number with age and are seen in approximately two-thirds of patients.

2024年11月8日 · Aberrant arachnoid granulations, also known as arachnoid pits, are arachnoid granulations that penetrated the dura but failed to migrate normally in the venous sinus. They are most often located in the greater wing of the sphenoid bone and may be seen in idiopathic intracranial hypertension.

Arachnoid granulations produce well-defined focal filling defects within the dural venous sinuses. They are isoattenuating (one-third) or hypoattenuating (two-thirds) relative to brain parenchyma on unenhanced CT 1.

Normal appearance of arachnoid granulations on contrast-enhanced CT and MR of the brain: differentiation from dural sinus disease. appearance, distribution, and frequency of oc-currence of these normal structures is needed to prevent the erroneous diagnosis of venous sinus disease.

Arachnoid granulations (AGs, Pacchionian bodies or granulations) are protrusions of subarachnoid space into the cerebral venous sinus lumen. On dedicated imaging, AGs may be found in 60–90% of individuals, most commonly adjacent and/or within the superior sagittal, transverse, and straight sinuses.

Discrete filling defects, consistent with arachnoid granulations, may be seen in the dural sinuses on 24% of contrast-enhanced CT scans and on 13% of MR studies. They are focal, well-defined, and typically located within the lateral transverse sinuses adjacent to venous entrance sites.

SUMMARY: Arachnoid granulations are rarely seen on high-resolution CT (HRCT) at the posterior temporal bone wall, where they appear as erosions, without bone spicules and often with a lobulated surface. Differential diagnosis includes endolymphatic sac tumor, paraganglioma, chordoma, and chondromatous and metastatic tumors.

1996年9月1日 · Normal appearance of arachnoid granulations on contrast-enhanced CT and MR of the brain: differentiation from dural sinus disease. PURPOSE To determine the imaging appearance and frequency with which arachnoid granulations are seen on contrast-enhanced CT and MR studies of the brain.

2011年11月21日 · Normal drainage of CSF occurs from subarachnoid space into venous system via microscopic Arachnoid villi, measure a few millimetres, are growths of arachnoid membrane into the dural sinuses. When these villi are distended and visible to the naked eye are termed as Giant Arachnoid granulations, are noted and passed off as an incidental finding.

CT shows a filling defect in the left transversal sinus. A radiologist suspected transversal sinus thrombosis, so an MRI brain was advised. There is an oval filling defect in the left transversal sinus with signal intensity of the CSF in all sequences, with …