Accuracy of dementia diagnosis: a direct comparison between radiologists and a computerized method.
There has been recent interest in the application of machine learning techniques to neuroimaging-based diagnosis. These methods promise fully automated, standard PC-based clinical decisions, unbiased by variable radiological expertise. We recently used support vector machines (SVMs) to separate sporadic Alzheimer's disease from normal ageing and from fronto-temporal lobar degeneration (FTLD). In this study, we compare the results to those obtained by radiologists. A binary diagnostic classification was made by six radiologists with different levels of experience on the same scans and information that had been previously analysed with SVM. SVMs correctly classified 95% (sensitivity/specificity: 95/95) of sporadic Alzheimer's disease and controls into their respective groups. Radiologists correctly classified 65-95% (median 89%; sensitivity/specificity: 88/90) of scans. SVM correctly classified another set of sporadic Alzheimer's disease in 93% (sensitivity/specificity: 100/86) of cases, whereas radiologists ranged between 80% and 90% (median 83%; sensitivity/specificity: 80/85). SVMs were better at separating patients with sporadic Alzheimer's disease from those with FTLD (SVM 89%; sensitivity/specificity: 83/95; compared to radiological range from 63% to 83%; median 71%; sensitivity/specificity: 64/76). Radiologists were always accurate when they reported a high degree of diagnostic confidence. The results show that well-trained neuroradiologists classify typical Alzheimer's disease-associated scans comparable to SVMs. However, SVMs require no expert knowledge and trained SVMs can readily be exchanged between centres for use in diagnostic classification. These results are encouraging and indicate a role for computerized diagnostic methods in clinical practice.
Department of Psychiatry and Psychotherapy and Freiburg Brain Imaging, University Clinic Freiburg, Freiburg, Germany. stefan.kloeppel@uniklinik-freiburg.de
Stefan
S
Klöppel
Cynthia M
CM
Stonnington
Josephine
J
Barnes
Frederick
F
Chen
Carlton
C
Chu
Catriona D
CD
Good
Irina
I
Mader
L Anne
LA
Mitchell
Ameet C
AC
Patel
Catherine C
CC
Roberts
Nick C
NC
Fox
Clifford R
CR
Jack
John
J
Ashburner
Richard S J
RS
Frackowiak
D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000473:pathology; D000544:Alzheimer Disease / Q000175:diagnosis*; D001921:Brain / Q000473:pathology*; D002983:Clinical Competence; D003704:Dementia / Q000175:diagnosis; D003937:Diagnosis, Differential; D004812:Epidemiologic Methods; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D010363:Pattern Recognition, Automated