The value of rACC in diagnosing dementia of Alzheimer type with 11C-PIB PET

Objective Beta-amyloid (AB) plaque is one of the most important hallmarks of Alzhe-imer disease (AD). [N-methyl-11C]-[4'-methylaminophenyl]-6-hydroxybenzothiazole (11C-PIB) can have a strong binding potential (BP) of AB plaques in the brains of patients with dementia of Alzheimer type (DAT). This study was to investigate the value of rostral anterior cingnlate cortex (rACC) in diagnosing human AD with 11C-PIB PET imaging. Methods All the subjects were enrolled through ads by Washington University School of Medicine (WUSM) in USA. Clinical dementia rating (CDR) was the practical grading standard for AD. There were 129 cases of normal control (HC) with CDR =0 and 40 cases of AD patients with CDR >0 (but there were only 120 HC cases and 34 DAT patients with data of rACC PIB BP. All 169 cases had PIB BP data of other studied cerebral subregions). Brain subregions were localized with MRI. PET imaging was performed immediately after intravenous injection of11C-PIB. MRI and PET images were aligned and fused with the help of software. BP was calculated using the Logan graphical analysis and the cerebellar cortex as the reference tissue. The distribution characters of 11C-PIB BP in rACC were analyzed and compared with other brain subregions studied by other scholars with the same research cases. The corre-lation analysis, t-test or variance analysis were calculated with SPSS 11.5. Results rACC PIB BP of 120 HC and 34 AD patients was calculated, rACC PIB BP was statistically linear and positively correlated with CDR significantly (BP=0.2865±0.442,CDR=0.143±0.290,r=0.545,P 0.05), but signifi-cant difference was found between rACC PIB BPs of HC and DAT patients (0.1589±0.0219 vs 0.7370±0.1125, independent-samples t-test in both group of CDR=0 and>0,indicatedt=-7.998, P<0.01). The threshold of rACC PIB BP for differentiating DAT was 0.4592, greater than what could be thought as suffering from DAT with sensitivity 67.65 % (23/34) and specificity 88.33% (106/120). The BP values of both groups partially overlap each other. In all the studied cerebral subregions, the highest 3 subregions in mean PIB BP of DAT patients or in the difference of mean PIB BP between DAT patients and HC group were precuneus, rACC and prefrontal cortices. Conclusion rACC PIB BP can be used to differentiate DAT patients from normal persons; rACC, precuneus and prefrontal cortices are together the most sensitive brain subregions in the diagnosing DAT. Key words: Alzheimer's disease;  Dementia;  Gyrus cinguli;  Tomography, emission-computed;  PIB