Purpose: The present study investigated (a) the agreement between computerized tomography (CT) and 3 T magnetic resonance imaging (MRI) in the visual grading of medial temporal atrophy (MTA); and (b) whether MTA on CT differentiated patients with dementia from no dementia in memory clinics. Materials and Methods: Data were obtained from patients who underwent CT scans at the National University Hospital of Singapore, and from a subsample who subsequently underwent 3 T MRI scans in a research study. Agreements and disagreements between CT and MRI were determined. Area under the curve (AUC) analyses determined if CT-graded MTA distinguished patients with dementia from no dementia. Results: Of the 107 patients in the subsample, MTA scores of 71 agreed on both CT and MRI. The true positive rate between CT and MRI for MTA scores ≥2 was 79.7%. The true negative rate for MTA scores between 0 and 1 was 96.4%. CT underestimated MTA severity in 33 of 36 disagreements with the MRI. MTA scores ≥2 on CT distinguished dementia from no dementia in both discovery [n=263; AUC (95% confidence interval)=0.77 (0.72-0.83); sensitivity=0.69; specificity=0.74] and validation [n=264; AUC (95% confidence interval)=0.77 (0.71-0.82); sensitivity=0.72; specificity=0.72] groups. Conclusions: MTA graded on CT is a viable alternative to MRI to aid in the diagnosis of dementia in memory clinics.

CT, dementia, diagnostic validity, medial temporal atrophy, memory clinic, MRI
dx.doi.org/10.1097/WAD.0000000000000227, hdl.handle.net/1765/107433
Alzheimer Disease and Associated Disorders
Department of Epidemiology

Thiagarajan, S. (Sasinthiran), Shaik, M.A. (Muhammad A.), Venketasubramanian, N, Ting, E.Y.S. (Eric Y.S.), Hilal, S, & Chen, C. (2018). Coronal CT is Comparable to MR Imaging in Aiding Diagnosis of Dementia in a Memory Clinic in Singapore. Alzheimer Disease and Associated Disorders, 32(2), 94–100. doi:10.1097/WAD.0000000000000227