Arachnoid Granulations: Frequency and Distribution in Multi-Detector Row CT of Dural Sinuses

ABSTRACT

Arachnoid granulations are normal variants that protrude into the cerebral venous sinus lumen and produce focal defects in cerebral venography, contrast enhanced CT, and MRI. It should be differentiated from other lesions within the dural sinus lumen that produce focal defects. In the present study, we investigated the frequency and positional distribution of arachnoid granulations with multi-detector row CT. Simple post processing procedures on thin slice multi-detector row CT were performed. We found arachnoid granulations in nearly half of our participants. We observed that presence of arachnoid granulations showed no tendency in two sexes. No relationship between age and multiplicity, and an inverse relationship between age and the variants' size existed. We concluded that as imaging technology continues to develop, the frequency with which normal variants are identified will also increase. Arachnoid granulations are a normal variant that all radiologists should be aware of and which should not be mistaken for pathological intra-sinus lesions. The relationship between characteristics of the variant (presence, number, size) and of the human subjects (gender, age) should be reviewed with larger samples.

Keywords:

• arachnoid granulation
• dural sinus
• MDCT
• CT-venography