CTA and MRA for Arterial Dissection Evaluation

Primary Recommendation: CTA as First-Line Imaging

The American College of Radiology recommends CTA as the primary imaging modality for dissection evaluation due to its superior spatial resolution, rapid acquisition time, and widespread availability, achieving 98-100% sensitivity and specificity for detecting dissection 1, 2
CTA offers superior spatial resolution compared to MRA, allowing better visualization of the intimal flap, entry tears, and branch vessel involvement 3, 4, 5
CTA has faster scan times, reducing motion artifact and making it ideal for unstable patients 3, 4
CTA has immediate availability in emergency settings, whereas MRA is often not available on an emergency basis 6
CTA has better tolerance of metal artifacts from prior surgical hardware or implanted devices 3, 4

For cervical arterial dissection, CTA is slightly preferable to MRA for identification of blunt cervical arterial injuries 7, 8
CTA has a sensitivity of 41-98% and specificity of 81-100% for cervical arterial dissection 7, 8
MRA may be superior for detecting intramural hematoma in cervical vessels using T1-weighted fat-suppressed sequences 7, 8

For acute/unstable patients with suspected dissection, the American College of Radiology recommends using CTA due to its faster acquisition time and wider availability 1
For stable patients with renal dysfunction or contrast allergy, non-contrast MRA with ECG-gating is recommended 6
For suspected intramural hematoma, MRA is considered due to its superior soft-tissue characterization 7, 8, 6