Variant 1: Asymptomatic. Structural lesion on physical examination (cervical bruit) and/or risk factors.
Variant 2: Carotid territory or vertebrobasilar TIA, initial screening survey.
Variant 3: New focal neurologic defect, fixed or worsening. Less than 6 hours. Suspected stroke.
Variant 4: New focal neurologic defect, fixed or worsening. Longer than 6 hours. Suspected stroke.
Variant 5: Risk of unruptured aneurysm, including patients with polycystic kidney disease, patients who have at least two first-degree relatives with history of subarachnoid hemorrhage (SAH), and those with previously ruptured and treated aneurysms.
Variant 6: Clinically suspected acute SAH, not yet confirmed.
Variant 7: Proven SAH by lumbar puncture or imaging.
Variant 8: Proven SAH, negative angiogram, follow-up.
Variant 9: Asymptomatic or no new symptoms. Follow-up imaging of previously treated cerebral aneurysms.
Variant 10: Asymptomatic or no new symptoms. Follow-up imaging of untreated cerebral aneurysms.
Variant 11: Evaluation for cerebral vasospasm after aneurysmal SAH.
Variant 12: Clinically suspected parenchymal hemorrhage (hematoma), not yet confirmed.
Variant 13: Proven parenchymal hemorrhage (hematoma).
Variant 14: Evaluation of high-flow vascular malformations.
Variant 15: Suspected dural venous sinus thrombosis.
Variant 16: Central nervous system vasculitis.
Appendix Key

A more complete discussion of the items presented below can be found by accessing the supporting documents at the designated hyperlinks.

Appropriateness Category:The panel’s recommendation for a procedure based on the assessment of the risks and benefits of performing the procedure for the specified clinical scenario.

SOE: Strength of Evidence. The assessment of the amount and quality of evidence found in the peer reviewed medical literature for an appropriateness recommendation.

  • References: The citation number and PMID for the reference(s) associated with the recommendation.
  • Study Quality: The assessment of the quality of an individual reference based on the number of study quality elements described in the reference.

RRL: Relative Radiation Level. A population based assessment of the amount of radiation a typical patient may be exposed to during the specified procedure.

Rating: The final rating (1-9 scale) for the procedure as determined by the panel during rating rounds.

Median: The median rating (1-9 scale) for the procedure as determined by the panel during rating rounds.

Final tabulations: A histogram showing the number of panel members who rated the procedure as noted in the column heading (ie, 1, 2, 3, etc.).

Additional supporting documents about the AC methodology and processes can be found at www.acr.org/ac.