Table 1.
Recommendations from CCCDTD4 for the clinical use of imaging procedures
| X-ray computerized tomography and magnetic resonance imaging |
| • We recommend a head MRI when a radiologist/neuroradiologist and/or a cognitive specialist (neurologist, geriatrician, or geriatric psychiatrist) can interpret patterns of atrophy and other features that may provide added diagnostic and predictive value as deemed appropriate by the specialist (Grade 2B) |
| • Standardization of clinical acquisition of core MRI dementia sequences is recommended in Canadian centers that have radiologists and cognitive specialists with expertise in assessing cognitive disorders, particularly when repeat MRI scans can provide additional diagnostic, prognostic and safety information (Grade 2B) |
| • In addition to previously listed indications for structural imaging, a CT or MRI scan should be undertaken in the assessment of a person with cognitive impairment if the presence of unsuspected cerebrovascular disease would change the clinical management |
| • The practical message is that structural imaging is not required in all (although will be indicated in most) persons with cognitive impairment. Although more costly and less available, MRI is preferable to CT |
| • When available in the clinic, we recommend that cognition specialists use the computer images of the brain to educate persons with cognitive impairment about changes in the brain. This knowledge may reinforce adherence to vascular risk factors management and to life style modifications to improve brain health (Grade 3C) |
| • We recommend against the use of functional MRI for the clinical investigation of patients presenting with cognitive complaint (Grade 1B) |
| • Magnetic resonance spectroscopy is not currently recommended for clinical use to make or differentiate a diagnosis of dementia in people presenting with mild cognitive impairment (Grade 2C). |
| FDG-PET and SPECT regional cerebral blood flow imaging |
| • For a patient with a diagnosis of dementia who has undergone the recommended baseline clinical and structural brain imaging evaluation and who has been evaluated by a dementia specialist but whose underlying pathological process is still unclear, preventing adequate clinical management, we recommend that the specialist obtains an 18F-FDG PET scan for differential diagnosis purposes (Grade 1B) |
| • If such a patient cannot be practically referred for a FDG-PET scan, we recommend that a SPECT rCBF study be performed for differential diagnosis purposes (Grade 2C) |
| • There was only partial consensus for the proposition that for a patient with MCI evaluated by a dementia specialist and in whom clinical management would be influenced by evidence of an underlying neurodegenerative process, an 18F-FDG PET scan be performed or, if not available, then a SPECT rCBF study be performed |
| PET amyloid imaging |
| • Although amyloid imaging represents a promising technique in the evaluation of dementia, there are many unknowns that could impact on its diagnostic utility and we therefore recommend that its use be restricted to research at present (Level 1C) |
| Other neuroimaging modalities |
| • Imaging biomarkers of neuroinflammation or tau pathology in dementia patients are not recommended in clinical practice. Although there is a growing body of literature supporting the use of dopamine presynaptic imaging agents for differentiating dementia with Lewy bodies from Alzheimer's disease, these imaging agents are not yet recommendable for clinical practice |
CCCDTD4, Fourth Canadian Consensus Conference on the Diagnosis and Treatment of Dementia; CT, X-ray computerized tomography; 18F-fluorine-18; FDG, fluorodeoxyglucose; MRI, magnetic resonance imaging; PET, positron emission tomography; rCBF, regional cerebral blood flow; SPECT, single-photon emission computed tomography.