Structural radiography. Magnetic resonance imaging can reveal brain tissue loss patterns characteristic of Alzheimer’s, and is seen as a useful adjunct to standard methods. MRI can help to differentiate AD cases from other types of dementia, particularly frontal lobe dementia. Recent MRI studies confirm postmortem findings of marked neuronal loss in specific areas of the entorhinal cortex at the earliest stages of AD (see Juottonen et al., 1998). It seems likely that this type of MRI diagnostics will become an important tool for identifying individuals who can benefit from therapies to delay or prevent the progression of the disease. Such tests should become available at any large hospital with high-resolution MRI capabilities.

Functional radiography: Radiological tools that detect focal hypometabolism in the brain have shown promising results, and are increasingly seen as useful adjuncts in the differential diagnosis of AD. These tests involve somewhat invasive techniques(such as injecting a low-level radioisotope into the blood) that are also expensive, although not more so than full-battery neuropsychological testing. PET (positron emission tomography) and SPECT (single photon emission computed tomography) are available at any hospital with a nuclear medicine division (see Read, S.L. et al., 1995; and Small, G.W., 1996). Functional MRI has the advantage of being noninvasive, but is still a research tool and not widely available.

See the Alzheimer's Association working group's Consensus Report on MRI and PET imaging for diagnosis of dementias. (.pdf)