Condition Specific Radiology: Cerebral Arteriovenous Malformation

OVERVIEW

This page is dedicated to covering how the condition cerebral arteriovenous malformation will appear on different types of imaging studies.

BASIC CHARACTERISTICS

Fundamentally, a cerebral arteriovenous malformation refers to an abnormal tangle of vessels in the brain, where arteries are connected directly to veins. This creates a shunt where arterial blood bypasses the brain parenchyma and goes straight to the venous system. Typically this malformation will have feeding arteries, a nidus (nest of vessels comprised of both shunting arterioles and interconnected venous loops), and draining veins.

Here are some general features of this condition that might be appreciated across modalities:

• Tangled nest of vessels (nidus): this is the central location of the malformation. Its appearance can look like a “bag of worms” across imaging studies.
• Enlarged feeding vessels may be appreciated across varies studies (dilated arteries).
• Dilated draining vessels may be appreciated across varies studies. A venous varix may be present as well.
• Calcifications may be present in the nidus

COMPUTERIZED TOMOGRAPHY: NON-CONTRAST HEAD CT-SCAN

Key features of the appearance of cerebral cavernous malformation on this imaging modality are:

• Hyperdense appearance (relative to normal brain) on a non-contrast study (may be difficult to appreciate)
• Calcifications are best appreciated in the absence of contrast
• Signs of hemorrhage may be present and can be appreciated best on a non-contrast head CT.

Example 1

Example 2.1

Example 2.2

Example 2.3

COMPUTERIZED TOMOGRAPHY: IV CONTRAST HEAD CT-SCAN

Key features of the appearance of cerebral cavernous malformation on this imaging modality are:

• Contrast enhancing “bag of worms” appearance when IV contrast is used
• Enlarged feeding vessels/dilated draining vessels more clearly visualized due to the usage of contrast.

Example 1.1

Example 1.2

CT ANGIOGRAPHY (CTA)

Key features of the appearance of cerebral cavernous malformation on this imaging modality are:

• Contrast enhancing “bag of worms” appearance when IV contrast is used
• Enlarged feeding vessels/dilated draining vessels more clearly visualized due to the usage of contrast and also the ability to process the data and create vessel maps from the CTA.

Example 1.1

Example 1.2

MAGNETIC RESONANCE IMAGING: SUSCEPTIBILITY SEQUENCE HEAD MRI (GRE/SWI)

Key features of the appearance of cerebral cavernous malformation on this imaging modality are:

• No susceptibility artifact: there will not be an area of lost signal in the entire area of the malformation on GRE/SWI studies

Example 1

MAGNETIC RESONANCE IMAGING: T1 WEIGHTED HEAD MRI

Key features of the appearance of cerebral cavernous malformation on this imaging modality are:

• Fast flow voids seen in the nidus: this can be appreciated on T1 imaging. Blood can move so quickly through the malformation that it does not return a signal to the MRI scanner (and will appear black).
• Incomplete contrast enhancement: some portions of the nidus may enhance partially, however much of the nidus will not enhance with contrast due to the speed of blood flow.

Example 1.1

Example 1.2

MAGNETIC RESONANCE IMAGING: T2 WEIGHTED HEAD MRI

Key features of the appearance of cerebral cavernous malformation on this imaging modality are:

• Fast flow voids seen in the nidus: this can be appreciated on various sequences, especially T2 weighted imaging. Blood can move so quickly through the malformation that it does not return a signal to the MRI scanner (and will appear black).

Example 1

Page Updated: 08.09.2017