Table 1 Diagnostic criteria for cervicocephalic arterial dissection

Major criteria

1. “Double lumen” or “intimal flap” demonstrated on either DSA, MRI, MRA, CTA, or duplex ultrasonography

2. “Pearl and string sign” or “string sign” demonstrated on DSA

3. Pathological confirmation of arterial dissection

Minor criteria

4. “Pearl sign” or “tapered occlusion” demonstrated on DSA

5. “Pearl and string sign,” “string sign,” or “tapered occlusion” demonstrated on MRA

6. “Hyperintense intramural signal” (corresponding to intramural hematoma) demonstrated on T1-weighted MRI

Additional criteria

7. Change in arterial shape demonstrated on either DSA, MRI, MRA, CTA, or duplex ultrasonography

8. No other causes of arterial abnormalities

Definite dissection

Presence of one or more major criteria, or presence of one or more minor criteria and both of 2 additional criteria

Probable dissection

Presence of one or more minor criteria