RT Journal Article
SR Electronic
T1 Relationship Between Vasodilatation and Cerebral Blood Flow Increase in Impaired Hemodynamics: A PET Study with the Acetazolamide Test in Cerebrovascular Disease
JF Journal of Nuclear Medicine
JO J Nucl Med
FD Society of Nuclear Medicine
SP 1875
OP 1883
VO 44
IS 12
A1 Hidehiko Okazawa
A1 Hiroshi Yamauchi
A1 Hiroshi Toyoda
A1 Kanji Sugimoto
A1 Yasuhisa Fujibayashi
A1 Yoshiharu Yonekura
YR 2003
UL http://jnm.snmjournals.org/content/44/12/1875.abstract
AB The changes in cerebral blood flow (CBF) and arterial-to-capillary blood volume (V0) induced by acetazolamide (ACZ) are expected to be parallel each other in the normal circulation; however, it has not been proven that the same changes in those parameters are observed in patients with cerebrovascular disease. To investigate the relationship between changes in CBF, vasodilatory capacity, and other hemodynamic parameters, the ACZ test was performed after an 15O-gas PET study. Methods: Twenty-two patients with unilateral major cerebral arterial occlusive disease underwent PET scans using the H215O bolus method with the ACZ test after the 15O-gas steady-state method. CBF and V0 for each subject were calculated using the 3-weighted integral method as well as the nonlinear least-squares fitting method. After evaluation of accuracy in V0 values, a new parameter, the CBF/V0 ratio, which is expected to disclose arterial perfusion pressure, was also compared between the conditions. Results: The regional CBF (rCBF) and V0 increased significantly after ACZ administration in the hemisphere contralateral to the ischemic side. However, in a subgroup of patients who showed a significant reduction in the rCBF increase in the ipsilateral hemisphere (group A), the ACZ injection caused no change or a slight decrease in rCBF even though the V0 showed a significant increase. Thus, the increases in rCBF and V0 did not necessarily parallel each other in the ipsilateral hemispheres of patients who have impaired cerebral circulation. A parameter defined by the rCBF/V0 ratio decreased significantly in the ipsilateral hemisphere of group A after ACZ administration, although the ratio showed no change in the contralateral hemisphere or in the other subgroup (group B). Conclusion: The change in the rCBF/V0 ratio after ACZ challenge may represent an alteration in arterial perfusion pressure that is expected to indicate a critical hemodynamic status in patients with cerebrovascular disease, especially in patients who have a reduced rCBF response.