Regional cerebral blood flow assessed with 99mTc-ECD SPET as a marker of progression of mild cognitive impairment to Alzheimer's disease

• Published in: European journal of nuclear medicine and molecular imaging 2003-11, Vol.30 (11), p.1473-1480
• Main Authors: Encinas, Marta, De Juan, Ramón, Marcos, Alberto, Gil, Pedro, Barabash, Ana, Fernández, Cristina, De Ugarte, Carmen, Cabranes, José Antonio
• Format: Article
• Language: English
• Subjects: Aged; Alzheimer Disease - complications; Alzheimer Disease - diagnosis; Alzheimer Disease - diagnostic imaging; Brain - blood supply; Brain - diagnostic imaging; Cerebrovascular Circulation; Cognition Disorders - diagnosis; Cognition Disorders - diagnostic imaging; Cognition Disorders - etiology; Cysteine - analogs & derivatives; Disease Progression; Female; Humans; Longitudinal Ligaments; Male; Organotechnetium Compounds; Prognosis; Radiopharmaceuticals; Reproducibility of Results; Risk Assessment - methods; Risk Factors; Sensitivity and Specificity; Severity of Illness Index; Statistics as Topic; Tomography, Emission-Computed, Single-Photon - methods
• ISSN: 1619-7070; 1619-7089
• DOI: 10.1007/s00259-003-1277-z

Patients diagnosed with mild cognitive impairment (MCI) have a higher risk of developing Alzheimer's disease (AD). However, not all such patients develop this kind of dementia. The purpose of this prospective study was to assess whether regional cerebral blood flow (rCBF) patterns measured with technetium-99m ethyl cysteinate dimer single-photon emission tomography ((99m)Tc-ECD SPET) in patients suffering from MCI are useful in predicting progression to AD. The study group comprised 42 patients who fulfilled MCI criteria according to the International Psychogeriatric Association and the Alzheimer's Disease Cooperative Study. rCBF was calculated in 16 regions of interest (ROIs). All patients were clinically assessed for 1-3 years. Twenty-one developed AD (group I) while the initial diagnosis of MCI was retained in the other 21 (group II). ROC curves were designed, and sensitivity, specificity, positive and negative predictive values, and positive and negative likelihood ratios were determined for each ROI. Compared with group II (MCI), group I (AD) showed a significant reduction of relative blood flow (RBF), ranging from 7% to 10%, in the following areas: right and left prefrontal, right and left frontal, right and left parietal, right and left temporal, right and left frontoparietotemporal and left posterior lateral temporal. Left prefrontal, left frontal and left parietal areas showed sensitivities and specificities higher than 75% and areas below the ROC curve close to 80%. This study shows that RBF patterns in the right and left prefrontal, right and left frontal and left parietal areas are sensitive early markers of progression towards AD. Reduction of rCBF in the medial temporal and anterior lateral temporal cortex has no value as a predictor since it also occurs in patients with MCI who remain stable.