In Alzheimer disease, CSF biomarkers and nuclear imaging are of particular interest. Many studies investigated only one technique, limiting comparison. Here, in 76 patients blinded 99mTc-SPECT was compared to CSF. Sensitivity of CSF was 92%; and 51% for SPECT. Specificity favored SPECT (90 vs. 80%). Both techniques showed no coherence (p = 0.17-0.47). Our results confirm that CSF biomarkers show higher sensitivity. SPECT has higher specificity and can also be used for other dementias without established CSF biomarkers.