Abstract TMP12: MR Diffusion and CT ASPECTS Disparities as a Function of Time From Presentation: Analysis and Implications for Acute Stroke Triage
Introduction: In April of 2010, the Cleveland Clinic switched to an MR based triage for candidates for intra-arterial thrombolysis and thrombectomy, yielding a patient cohort that was imaged with both MRI and CT allowing comparison of imaging characteristics and an analysis of current triage algorithms employed. The investigators sought to ascertain what differences in DWI and MRI ASPECTS scores might be present in this cohort as a function of time from symptom onset, hypothesizing that the degree of mismatch may increase and/or decrease given that the imaging findings of ischemia become apparent on CT and MRI at different rates. Such a difference may have implications for designing imaging triage regimes for stroke centers.
Methods: The Cleveland Clinic Acute Stroke Database was queried, excluding patients with incomplete data, yielding 291 patients. Time of the latest pre-treatment CT exam, MR exam and CTA exam was recorded as a function of time vs. the time the patient was last known well. ASPECTS score was assessed for each CT, CTA and MR exam. CT and CTA were used to determine a representative CT ASPECTS Score, using whichever was obtained closer to the time of the MRI.
Secondary Analysis: Using an ASPECTS score of 7 as a discriminator for IA treatment, we assessed whether a given image would or would not have been selected for IA therapy, and assessed whether the DWI information would have resulted in a change in therapy.
Results: Figure 1 shows a scatter plot of the time between onset and MRI imaging, and the disparity between CT ASPECTS and MRI ASPECTS.
Conclusion: The mismatch between DWI and CT/CTA appears to be greatest between 180-420 minutes between onset to MRI, suggesting that MRI DWI regimes may be most valuable in patients during this period. Further analysis is needed in order to further refine acute stroke triage paradigms.
- © 2012 by American Heart Association, Inc.