What is Evans ratio?
Evans’ index is the ratio of the maximum width of the frontal horns of the lateral ventricles and the maximal internal diameter of the skull at the same level employed in axial CT and MRI images.
What is the best imaging modality for hydrocephalus?
MR imaging is the premier imaging modality for diagnosing the various forms and causes of hydrocephalus. Although CT is satisfactory for imaging in the axial plane, MR imaging is capable of imaging in any plane to better demonstrate any cause of observation.
What is ventricular index?
The ventricular index (VI), or width, is widely used as a tool for monitoring ventricular size. It is a measurement of the distance from the falx to the lateral border of the lateral ventricle in a coronal view taken at the level of the Foramen of Monro.
How is Evans index calculated?
The Evans index is determined by the largest diameter of the frontal horns divided by the diameter of the internal skull, on the same plane. A value greater than 0.3 for the Evans index is the only essential morphologic criterion of probable INPH as reported in the journal Neurosurgery and ‘ the Japanese guidelines ‘ .
When hydrocephalus is suspected what diagnostic procedures are likely performed?
Ultrasound. This test is often used for an initial assessment for infants because it’s a relatively simple, low-risk procedure. The ultrasound device is placed over the soft spot (fontanel) on the top of a baby’s head. Ultrasound might also detect hydrocephalus before birth during routine prenatal examinations.
Can a lumbar puncture diagnose hydrocephalus?
When a large volume lumbar puncture is used to assess normal pressure hydrocephalus, your doctor will assess your gait and balance both before and after the procedure to see if removal of CSF results in a significant improvement. These tests will help guide treatment decisions.
What are the two major types of hydrocephalus?
The two major types of hydrocephalus are called communicating hydrocephalus and non-communicating hydrocephalus.
- Communicating hydrocephalus occurs when the flow of CSF is blocked after it exits the ventricles.
- Congenital hydrocephalus.
- Acquired hydrocephalus.
What does hydrocephalus look like on CT?
CT/MRI criteria for acute hydrocephalus include the following: Size of both temporal horns is greater than 2 mm, clearly visible. In the absence of hydrocephalus, the temporal horns should be barely visible.
Can hydrocephalus be diagnosed with a CT scan?
Treatment with penicillin significantly diminished the size of these high signal intensity on T2-weighted images with general paresis. Conclusion: These results suggest that MR and CT images have some characteristic manifestations in patients of neurosyphilis.
What are the CT/MRI criteria for acute hydrocephalus?
CT/MRI criteria for acute hydrocephalus include the following: Size of both temporal horns is greater than 2 mm, clearly visible. In the absence of hydrocephalus, the temporal horns should be barely visible. Ratio of the largest width of the frontal horns to maximal biparietal diameter (ie, Evans ratio) is greater than 30% in hydrocephalus.
How is hydrocephalus diagnosed radiographically?
e-Figure 32-4 Various methods of radiographically diagnosing hydrocephalus. A, The ventricular index is the ratio of the ventricular diameter at the level of the frontal horns to the diameter of the brain measured at the same level.
What are the classical clinical findings of normal pressure hydrocephalus?
The classical clinical findings of normal pressure hydrocephalus are 1-3. urinary incontinence. deterioration in cognition (dementia) gait disturbances.
What is the primary treatment for hydrocephalus?
The primary treatment of hydrocephalus caused by obstruction beyond the level of the fourth ventricular outlet is ventricular shunting. The most common complications of shunting are obstruction and infection.