What is Dynamic Angio in MRI? Why is MRI Brain with Dynamic Venography with Contrast done?

What is Dynamic Angio in MRI?

Dynamic Angiography in MRI (commonly referred to as Dynamic Contrast-Enhanced MRA or Time-Resolved MRA) is a specialized MRI technique used to visualize blood vessels dynamically over time—i.e., it captures a series of images as contrast flows through the vascular system.

Why it's called "Dynamic":

• Unlike static MRA (single snapshot), dynamic MRA captures multiple time frames after contrast injection.

• This allows visualization of arterial, capillary, and venous phases of blood flow—important for evaluating vascular timing, flow patterns, and pathology.

Why is MRI Brain with Dynamic Venography with Contrast done?

This is usually ordered when the clinician suspects a vascular abnormality involving the veins or sinovenous system of the brain. Here’s why:

1. Detect Cerebral Venous Thrombosis (CVT)

• Blood clots in venous sinuses may not show on non-contrast MRI.

• Dynamic contrast-enhanced MR venography shows how blood flows through the venous system, revealing blockages or slow flow.

2. Assess Arteriovenous Malformations (AVMs) or Fistulas

• Dynamic sequences show timing of contrast filling, helping differentiate between arteries and veins.

• Helps visualize abnormal connections or early venous drainage, characteristic of AVMs.

3. Evaluate Intracranial Hypertension

• Conditions like idiopathic intracranial hypertension (IIH) may involve transverse sinus stenosis, which is better seen with dynamic venography.

4. Detailed Mapping Before Surgery or Interventions

• Provides precise anatomy and timing of blood flow, guiding neurosurgical or endovascular planning.

Summary:

Technique	Purpose
Dynamic MRI Angio	Time-resolved imaging of arteries and/or veins during contrast injection.
MRI Brain with Venography (Dynamic Contrast)	Evaluates brain veins and sinuses over time — to detect clots, AVMs, fistulas, or venous stenosis.