Accuracy of MR Angiography and Transcranial Doppler for cerebral collateral flow: a comparison with iaDSA in 97 patients with carotid occlusion.
Hendrikse J, Mali W, Van der Grond J
The presence of functional collaterals is associated with relatively low stroke risk. Still it remains undetermined whether non-invasive methods can replace iaDSA for cerebral collateral flow measurements. In the present study we show that MRA and TCD collateral flow measurements should be interpreted with caution, for the presence of collateral flow via the anterior circle of Willis MRA and TCD are equally and highly accurate. For the posterior communicating artery, TCD tends to overestimate and MRA tends to underestimate the presence of collateral flow compared to iaDSA. Combined assessment with MRA and TCD did not result in substantial diagnostic gain.