2. Introduction
Brain CT venogram is a diagnostic imaging technique used to visualize the
veins in the brain.
It involves injecting contrast into a vein, then taking CT scans to create dilated
images of the brain blood vessels.
3. Brain venous anatomy.
The intracranial venous system has two major components,
1. Dural venous sinuses.
2. Cerebral veins.
6. Indications.
Suspected cerebral venous thrombosis.
Assessment of Dural sinus thrombosis.
Evaluation of intracranial hypertension.
Preoperative planning particularly for posterior fossa surgery where the
sigmoid sinuses may be compressed.
Monitoring response to treatment.
7. Contraindications.
Contrast media allergy.
Impaired renal function.
Blood-clotting disorders.
Anticoagulant medication.
Unstable cardiopulmonary or neurologic status.
Non-consent by patient to procedure.
Pregnancy.
8. Patient preparation
Some common procedure for patient preparation are:
Fasting for 4-6hrs prior to examination
Kidney functional assessment
Taking proper medical history so that appropriate premedication can be
used.
Changing patient to an appropriate gown.
Signing Informed consent
Remove all radiopaque objects
9. Patient positioning.
Patient should be in a supine position.
Head first into the gantry, with the head in the head holder whenever
possible.
Center the table height such that the external auditory meatus is at the
center of the gantry.
11. Technical factors
Topogram Position/Landmark-Lateral; 2-3 cm above the vertex.
Mode of Scanning-Helical.
Scan Orientation-CaudocraniaL
Starting Location-Level of the occipital squame.
End Location-To the level of the vertex.
Gantry Tilt-As many degrees required to make the plane of scanning
parallel to the canthomeatal line.
Field of View-Just fitting the skull including the soft tissues.
Contrast Administration-Intravenous.
Volume of Contrast-80-100 mL.
Rate of Injection of Contrast-3-4 mL/sec.
Scan Delay-80-100 sec.
Slice Thickness in Reconstruction-1.0-1.5 mm.
Respiration suspended.
12. Protocol.
Take the topogram of the head,
Adjust the parameters (keep scan delay as default 2 seconds)
We will monitor the time once we start injecting.
Set the amount of contrast to be given and inform the patient that you are going to
inject.
We will scan around 50 seconds
Always keep eyes on the injector time
Since we have default scan delay of two seconds, we will press the scan button at 48
seconds.
Before scanning, instruct patient not to move his/her head.
Acquisition is done.
13. Cont.
Reconstruct images (coronal, axial, sagittal)
Adjust each view to make image symmetrical
Survey through the constructed images.
16. MIP
It is a maximum intensity projection.
It consists of taking information from a set of source images (thin slices), and
putting together information across many other slices into thicker bundles
collapsing it down into a diagrammatic fashion.
