Evaluation and measurement of the normal ventricular and subarachnoid spaces by CT

✍ Scribed by L. Sabattini

• Book ID: 104757634
• Publisher: Springer
• Year: 1982
• Tongue: English
• Weight: 521 KB
• Volume: 23
• Category: Article
• ISSN: 0028-3940
• DOI: 10.1007/bf00399698

✦ Synopsis

The aim of this work is to analyze current literature with a view to define if and how the ventricles and subarachnoid spaces may be measured radiologically.

Before the advent of computed tomography (CT) measurements were made on pneumoencephalographic (PEG) pictures, mainly on AP views [2,5,6,7,8,9,18,21,30].

PEG methods present many sources of error: 1. The results can be influenced by the amount and location of air, brain swelling, or dilatation of the ventricles and cisterns which may occur some time after introduction of the air. It is therefore difficult to define the anatomical structures precisely. 2. There is some deformation due to the X-ray beams.

The classic measurement, obtained from the AP view of the PEG, is that of Evans, the ratio between the greatest width of the frontal horns and the inner table of the skull. This method has been widely used and is considered more reliable than direct measurements of the ventricles (Evans 1942). However, Zatz (1979) found an error in Evans' calculation, which applies equally to its use in CT.

CT should be prefered to PEG for many reasons: 1. the difficulties related to the contrast medium (air) do not exist;