Type:
Educational Exhibit
Keywords:
Not applicable, Education and training, Dilatation, Cerebrospinal fluid, History, Education, Complications, MR, CT-Angiography, CT, Management, Head and neck, Anatomy, Neuro
Authors:
A. N. Khan1, K. S. Babar1, U. S. Umer1, R. A. Shah2, M. Khan1, S. Shabir3, Z. Malik4, A. Jang1, M. Kumar5; 1Peshawar/PK, 2Islamabad/PK, 3Rawalpindi/PK, 4Islamabad /PK, 5Karachi/PK
DOI:
10.26044/ecr2020/C-15125
Findings and procedure details
This section includes key radiological findings, use of intracranial angles and spine imaging for SIH.
Key radiological findings in SIH:
The key imaging findings are due to following mechanisms;
1. Compensatory increase in venous blood volume.
2. Sagging of brain especially midbrain.
1. Imaging findings related to Compensatory increase in venous blood volume:
1. Engorgement of the venous sinuses. Rounded appearance of the venous sinuses is demonstrated on MRI. On sagittal images the convex bulging of the border of the transverse sinus is termed as the "venous distention" sign Fig. 4 .
2. Pachymeningeal enhancement. The pattern of meningeal enhancement is smooth and diffuse, involving exclusively the dura matter and sparing the leptomeninges Fig. 5, Fig. 6 and Fig. 7 .
3. Engorgement of the pituitary gland, which is due to pituitary hyperemia. Fig. 7
2. Imaging findings related to Sagging of brain especially midbrain.
1. Subdural collections. These are usually bilateral covering cerebral convexities and are likely due to rupture of bridging veins because of the descent of the brain [3] Fig. 2 and Fig. 6 .
2. Effacement of the CSF cisterns Fig. 3 .
3. Sagging of mid brain Fig. 3 .
4. Sagging of corpus callosum Fig. 3 and Fig. 8 .
5. Brain herniations, most commonly cerebellar tonsillar herniation Fig. 10 and Fig. 11 .
Use of intracranial angles for quantitative assessment of intracranial hypotension:
There are some intracranial angles which can help in accurate quantitative assessment of SIH. These include pontomesencephalic angle, mamillopontine distance, and lateral ventricular angle [4].
Lateral ventricular angle is between medial margins of right and left lateral ventricles. This angle is calculated on coronal imaging at level of fornices, third ventricle, and pituitary infundibulum. Mean value in patients with intracranial hypotension is 130.1°. Fig. 12 and Fig. 9.
Mamillopontine distance is distance between inferior aspect of mamillary bodies to superior aspect of pons. Mean value in patients with intracranial hypotension was 4.4 mm (SD, ± 1.8). Fig. 13 and Fig. 10.
Pontomesencephalic angle is angle between line drawn along anterior margin of midbrain and anterior superior margin of pons. Mean value in patients with intracranial hypotension was 41.2° (SD, ± 17.4°). Fig. 14 and Fig. 11.
Spine imaging for suspected CSF leak:
The patients of SIH with suspected CSF leaks should undergo whole spinal imaging. The spinal imaging done for CSF leaks include floroscopic, CT/MR myelography, nuclear medicine cisternography and digital subtraction myelography [5,6]. Fig. 15 , Fig. 17, Fig. 16 and Fig. 18.
Early diagnosis of CSF leak is very important for proper management which includes application of epidural patch.