Whitney B. Pope
“Imaging-negative” TIA presents an interesting clinical condundrum because although the patient’s symptoms are assigned to an underlying ischemic cause, there is no confirmatory evidence that that is truly the case. Previously, in collaboration with stroke investigators at UCLA, we had looked at the utility of arterial spin-labeling (ASL) in comparison to DSC imaging for acute stroke (and found that they were generally comparable for these patients), so it was a natural extension of our research efforts to use our database of patients with ASL imaging and neurologic symptoms to examine the potential use of ASL data for evaluating patients with TIA. We know that patients with TIA are at increased risk for stroke, and so we figured that the ability to improve the accuracy of this diagnosis would substantially affect clinical decision making.
Pending further studies, we see the possibility of using ASL for risk stratification of patients with transient neurologic deficits that are due to an underlying ischemic cause. An additional benefit of ASL over DSC perfusion imaging is the lack of requisite gadolinium contrast injection. As this patient population has increased risk for poor renal function, this is particularly useful. Thus, we now routinely acquire ASL on patients with TIA/stroke with compromised glomerular filtration rate.
In addition to the TIA work, we have looked at the utility of ASL imaging for primary brain tumors, and are extending this line of investigation to meningioma. For patients with TIA, our next goal is to perform ASL with multiple postlabeling delays, which offers the ability to quantify arterial transit times and potentially enhance the accuracy of this imaging biomarker. Another