[en] Mounting evidence from a variety of research fields has drawn attention to the participation of vascular factors in the underlying pathophysiology of Alzheimer's disease (AD). To clarify the influence of vascular and genetic risk factors, we investigated the relationships between cerebral blood flow images provided by single photon emission CT (SPECT) and blood pressure, brain natriuretic peptide (BNP), and ApoE4 phenotyping in AD patients. The present study was based on 197 patients with probable AD. All patients underwent biochemistry tests, neuropsychological evaluation, magnetic resonance imaging (MRI), and ^99mTc ethyl cysteinate dimer (ECD) SPECT. The mini mental state examination (MMSE) score was correlated with the diastolic blood pressure positively, and with BNP negatively. Statistical parametric mapping (SPM) revealed significant hypoperfusion in the posterior cingulate gyri, precuneus, and parieto-temporal region in those patients having ApoE4 as compared to those without ApoE4. When compared to those patients without white matter hyperintensity (WMH) on MRI, those with mild WHM demonstrated significant hypoperfusion in the anterior cingulate gyri, right superior, middle and inferior temporal gyri, and left inferior frontal gyrus, and those with marked WMH demonstrated more expansive hypoperfusion areas on SPM. Those with greater BNP levels showed significant hypoperfusion in the anterior cingulate gyri and superior frontal gyri as compared to those with smaller BNP levels. Posterior hypoperfusion as related to the presence of ApoE4 may imply a degenerative process in AD, whereas anterior hypoperfusion as related to increased BNP levels may indicate the participation of vascular factors in AD. (author)