Abstract 60: Multiphase versus Single Phase CT Angiography for Detection of Distal Intracranial Occlusion
Introduction: Detecting distal intracranial arterial occlusion is of increasing importance as current studies begin to evaluate the potential benefit of tPA in minor acute stroke. Multiphase CTA (mCTA) is a technique used routinely at our centre in the setting of suspected acute ischemic stroke (AIS).
Hypothesis: We hypothesized that mCTA is diagnostically superior to CTA for detection of distal intracranial arterial occlusion in suspected AIS.
Methods: Population comprised of patients with suspected AIS who had mCTA, followed by MR brain with DWI within 24 hours. mCTA involves 3 phases of enhanced CT from skull base to vertex following administration of a single iodinated contrast bolus. Prospective interpretation of unenhanced CT followed by single phase CTA was performed by a radiology resident, a stroke fellow, or a neuroradiologist. Unenhanced CT followed by mCTA was interpreted > 1 week after single phase CTA interpretation using the same dataset. MR exams were separately adjudicated to establish each case as positive or negative according to pre-specified criteria that suggests a high likelihood for the presence of an arterial occlusion on CTA (DWI lesion > 2mm diameter, not multiple small infarcts consistent with microembolic shower, not exclusively white matter lesion, not small deep gray matter lesion consistent with lacunar type infarct.
Results and Conclusion: Of 322 patients, single phase CTA detected 69 occlusions (sensitivity 52.5%, specificity 98.1%) and mCTA detected 113 (sens = 81.8%, spec = 99.5%). mCTA detected a greater number of proximal occlusions (76 vs. 66), and a greater number of distal occlusions (37 vs. 3) than CTA. mCTA demonstrated a greater rate of detection for distal occlusions (relative rate = 9.67, 95% CI 3.76 - 24.84). CTA/MR agreement was moderate (kappa = 0.59) while mCTA/MR agreement was substantial (kappa = 0.81). Mean interpretation time for CTA was 239.8 seconds (95% CI 221.3 - 258.4) and 195.0 seconds (95% CI 176.9 - 213.1) for mCTA.
In conclusion, our data suggest mCTA is superior to single phase for detection of distal intracranial occlusion.
Author Disclosures: B. Diederichs: None. B. Menon: None. P. Jo: None. C. Wallace: None. M. Willson: None. M. Joshi: None. M. Eesa: None. M. Goyal: None.
- © 2016 by American Heart Association, Inc.