CT of hydrocephalus
Author:
Mikael Häggström [notes 1]
Contents
Evaluation
Diagnosis
File:CT of Evan's index.jpg
Evan's index
Evan's index is the ratio of maximum width of the frontal horns to the maximum width of the inner table of the cranium. An Evan's index more than 0.31 indicates hydrocephalus.[1]
Causes
Attempt to indicate either of the main causes: Normal pressure hydrocephalus (NPH) versus cerebral atrophy (as part of CT in dementia):
| ||
| Preferable projection | Coronal plane at the level of the posterior commissure of the brain. | |
| Condition | Normal pressure hydrocephalus | Brain atrophy |
| Modality | CT | MRI |
| CSF spaces over the convexity near the vertex (red ellipse 20px) | Narrowed convexity ("tight convexity") as well as medial cisterns | Widened vertex (red arrow) and medial cisterns (green arrow) |
| Callosal angle (blue V) | Acute angle | Obtuse angle is typical of brain atrophy |
| Leucoaraiosis (periventricular signal alterations, blue arrows 25px) | May well represent transependymal CSF diapedesis due to NPH | Probably due to vascular encephalopathy, suggested by unilateral occurrence |
Notes
- ↑ For a full list of contributors, see article history. Creators of images are attributed at the image description pages, seen by clicking on the images. See Radlines:Authorship for details.
References
- ↑ Ishii, Mitsuaki; Kawamata, Toshio; Akiguchi, Ichiro; Yagi, Hideo; Watanabe, Yuko; Watanabe, Toshiyuki; Mashimo, Hideaki (2010). "Parkinsonian Symptomatology May Correlate with CT Findings before and after Shunting in Idiopathic Normal Pressure Hydrocephalus ". Parkinson's Disease 2010: 1–7. doi:. ISSN 2042-0080.
- ↑ Damasceno, Benito Pereira (2015). "Neuroimaging in normal pressure hydrocephalus ". Dementia & Neuropsychologia 9 (4): 350–355. doi:. ISSN 1980-5764.
