Abstract T P105: Decrease in Noninvasive Fractional Flow on MRA Is a Useful Marker of Misery Perfusion on SPECT
Background: Cerebrovascular reactivity to acetazolamide on 123I-IMP SPECT is used to detect misery perfusion due to intracranial atherosclerosis. Noninvasive fractional flow reserve (FFR) on time-of-flight magnetic resonance angiography (TOF-MRA) can provide a feasible alternative to identify high-risk intracranial atherosclerosis. We here demonstrate the association between FFR on TOF-MRA and cerebral blood flow pattern on 123I-IMP SPECT. Methods: Patients with a unilateral middle cerebral artery (MCA) stenosis who underwent both TOF-MRA and 123I-IMP SPECT with acetazolamide administration were retrospectively recruited from our radiology database. Signal intensity (SI) was measured in the background, proximal and distal to the stenotic lesion in the MCA on TOF-MRA. Adjusted FFR was calculated: FFR = [distal SI - background SI] / [proximal SI - background SI]. Mean cerebral blood flow (CBF) at rest, CBF after acetazolamide administration, and cerebrovascular reactivity (CVR) were measured in the target MCA territory. CBF patterns of MCA were divided into three: Stage II, CBF at rest of < 80% in that of normal subject and CVR below 10%; Stage 0, CVR over 30% regardless of CBF at rest, and Stage I, any other CBF patterns. We sought the optimum cut-off point for FFR to identify MCA territories with Stage II CBF on 123I-IMP SPECT. Results: A total of 41 sets of diagnostic imaging in 23 patients (mean age 57 y; 14 men, 9 women) was assessed. Four (9.8%) MCA territories demonstrated Stage II, 21 (51.2%) stage I, and 16 (39.0%) stage 0. Mean FFR of MCA with Stage II pattern was 0.59 (IQR 0.38 - 0.69), Stage I was 0.78 (IQR 0.70- 0.92), and Stage 0 was 0.90 (IQR 0.81 - 0.93). The optimal cut-off point for FFR to predict Stage II was ≤ 0.7 (sensitivity 100%; specificity 86%). Conclusion: In patients with unilateral MCA lesions, an FFR decrease was correlated with misery perfusion on 123I-IMP SPECT with acetazolamide, which may be a more feasible predictor of high-risk intracranial stenosis.
Author Disclosures: M. Miura: None. M. Nakajima: None. M. Watanabe: None. S. Shiraishi: None. Y. Ando: None.
- © 2015 by American Heart Association, Inc.