MRI Brain Plain Venogram (Non-Contrast MRV)

1. MRI Brain Plain Venogram (Non-Contrast MRV)

➤ Technique:

• Typically done using Time-of-Flight (TOF) or Phase Contrast (PC) sequences.

• No contrast agent is used.

➤ Advantages:

• Non-invasive: No need for IV contrast.

• Useful for screening or follow-up of known conditions.

• Safe for patients with renal impairment or allergies to contrast.

➤ Limitations:

• May miss slow-flowing blood, especially in distal sinuses or small veins.

• Can be prone to artifacts (especially TOF in-plane flow saturation).

• Difficult in patients with motion or metallic implants.

2. Contrast-Enhanced MR Venogram (CE-MRV)

➤ Technique:

• Uses Gadolinium-based contrast agent.

• 3D T1-weighted imaging post-contrast injection (timed to venous phase).

➤ Advantages:

• More accurate visualization of venous structures, especially small veins.

• Less prone to flow-related artifacts.

• Can evaluate both anatomy and pathology like thrombosis or malformations better.

➤ Limitations:

• Requires IV access and contrast agent, which is contraindicated in:

  • Patients with GFR <30 (renal failure)

  • Known gadolinium allergy

• Slightly more expensive and time-consuming.

🎯 Clinical Indications for MR Venography:

• Suspected Cerebral Venous Sinus Thrombosis (CVST)

• Vascular malformations

• Evaluation of intracranial hypertension

• Follow-up of known venous pathology