Follow-Up MRI for Small Brain AVMs Treated by Radiosurgery: Is Gadolinium Really Necessary?

Area of Science:

• Neuroradiology
• Medical Imaging
• Neurosurgery

Background:

• Current follow-up for brain arteriovenous malformations (AVMs) after radiosurgery primarily uses contrast-enhanced Magnetic Resonance (MR) imaging.
• Noncontrast MR techniques, specifically arterial spin-labeling (ASL) and Time-of-Flight (TOF), show potential for detecting residual AVM nidus post-treatment.

Purpose of the Study:

• To compare the efficacy of noncontrast (ASL/TOF) versus contrast-enhanced MR imaging in differentiating residual from obliterated brain AVMs.
• To evaluate the diagnostic performance of different MR imaging sequences in patients who have undergone radiosurgery for brain AVMs.

Main Methods:

• Twenty-eight patients with small brain AVMs (<20 mm) treated with radiosurgery were included.
• MR imaging protocols included postcontrast sequences, ASL/TOF sequences, and combined sequences.
• Three neuroradiologists independently assessed images for residual AVMs, with Digital Subtraction Angiography (DSA) as the reference standard.

Main Results:

• Arterial spin-labeling/TOF demonstrated the highest interobserver agreement (κ = 0.81).
• ASL/TOF showed significantly higher sensitivity (85%) compared to contrast-enhanced MR imaging (55%) for detecting residual AVMs (P = .008).
• Six residual AVMs identified on DSA were detected only with ASL/TOF, with three detected solely on ASL images.

Conclusions:

• Noncontrast arterial spin-labeling/TOF MR imaging is superior to gadolinium-enhanced MR imaging for detecting residual brain AVMs after radiosurgery.
• ASL/TOF offers improved sensitivity for identifying residual AVM nidus, potentially enhancing patient management and follow-up strategies.