Combination of a Mean Transit Time Measurement with an Acetazolamide Test Increases Predictive Power to Identify Elevated Oxygen Extraction Fraction in Occlusive Carotid Artery Diseases

Abstract

Reduced cerebral blood flow and cerebrovascular reactivity to acetazolamide have been used as predictors for subsequent ischemic stroke in patients with occlusive carotid artery diseases, called type 3 ischemia. However, recent studies have shown that reduced cerebrovascular reactivity to acetazolamide does not always represent elevated oxygen extraction fraction (OEF). The aim of this study was to establish the methodology to improve the validity of an acetazolamide test identifying elevated OEF. Methods: This study included 65 patients who developed transient ischemic attack or minor completed stroke attributable to occlusive carotid artery diseases. Hemodynamic and metabolic parameters in the bilateral middle cerebral artery territories were determined in all patients by 15 O-gas PET. Results: Type 3 ischemia alone had 100% sensitivity and 83.2% specificity for identifying elevated OEF, but its positive predictive value and accuracy were low, 47.2% and 0.85, respectively. However, type 3 ischemia and delayed mean transit time combined had an 83.3% positive predictive value and 0.96 accuracy. Conclusion: The results strongly suggest that type 3 ischemia and delayed mean transit time together may be powerful predictors in identifying elevated OEF with high sensitivity and specificity, predictive values, and accuracy. SPECT may be able to define the patients with elevated OEF more easily and at lower costs than PET, although further study would be necessary to compare the results by using SPECT.

Accuracy of Central Benzodiazepine Receptor Binding Potential/Cerebral Blood Flow SPECT Imaging for Detecting Misery Perfusion in Patients With Unilateral Major Cerebral Artery Occlusive Diseases

“…Although using the combination of CBF and CVR also improves the accuracy in detecting an elevated OEF, this effect is not sufficient. 9 Our data obtained using the 123 I-IMP-autoradiography method with SPECT corresponded to previous findings obtained using PET.…”

“…[7][8][9]30 Although most patients without reduced CBF or CVR have a normal OEF, only half of the patients with reduced CBF or CVR have an elevated OEF. Although using the combination of CBF and CVR also improves the accuracy in detecting an elevated OEF, this effect is not sufficient.…”

Detecting Misery Perfusion in Unilateral Steno-Occlusive Disease of the Internal Carotid Artery or Middle Cerebral Artery by MR Imaging

“…We found that OEF was significantly elevated in the hemisphere ipsilateral to the stenotic or occluded artery compared with the contralateral hemisphere, consistent with previous studies. 4,5,[17][18][19] This finding suggested the hemodynamic impairment in the hemisphere ipsilateral to the vascular lesion.…”

Apparent Diffusion Coefficient and Transient Neurological Deficit after Revascularization Surgery in Moyamoya Disease

“…They suggested that increased cerebral blood volume could indicate autoregulatory vasodilatation in response to cerebral perfusion pressure reduction and predict an increased oxygen ejection fraction in patients with adult MMD, on the basis of previous studies in patients with carotid occlusive disease. [22][23][24] Several parameters have been suggested to predict postoperative hyperperfusion, which includes as yet unexplained postoperative transient neurological deterioration associated with normalized or unchanged CBF on postoperative SPECT compared to preoperatively. In the present study, postoperative transient neurological deterioration was accurately predicted using Youden index.…”