HMPAO SPECT or SPECT/CT Brain Tc-99m HMPAO SPECT has been found to be useful in distinguishing FTD from AD and VaD with a pattern of bilateral anterior hypoperfusion. Tc-99m HMPAO SPECT may be used as an adjunct to clinical evaluation and CT but it is not a first-line test [50]. Variant 3: Suspected dementia with Lewy bodies. Initial imaging. Dementia with Lewy bodies (DLB) has been recognized as the second most prevalent neurodegenerative dementia in the elderly, causing up to 15% of cases [51]. It is a synucleinopathy with accumulation of insoluble alpha- Synuclein that aggregates to form Lewy bodies, which are the major pathological feature of the disease. To increase the accuracy of diagnosis of DLB, the latest diagnostic criteria incorporate findings from neuroimaging such as CT, MRI, SPECT, and PET [52]. Some authors have suggested a multimodality approach combining MRI and SPECT modalities as a useful and practical approach for differentiating DLB from AD [51]. CT Head Noncontrast CT head is a good first-line examination to exclude mimics like brain tumor or subdural hematoma. Relative preservation of the medial temporal lobe structures is also a supportive imaging biomarker according to the fourth consensus report of the DLB consortium [52]. CT with IV contrast or dual-phase CT imaging is not needed for initial evaluation. Dementia Amyloid PET/CT Brain DLB is also accompanied by amyloid deposition like AD, but overall, there is decreased uptake compared when with AD patients on amyloid imaging. Compared to Parkinson disease, DLB patients show a higher level of amyloid deposition [53]. At this time, amyloid PET/CT has very limited usefulness for diagnosis of DLB. Ioflupane SPECT or SPECT/CT Brain In the present guidelines, decreased dopamine transporter uptake is of the greatest importance among various neuroimaging findings and is listed as one of the suggestive features.
Dementia. HMPAO SPECT or SPECT/CT Brain Tc-99m HMPAO SPECT has been found to be useful in distinguishing FTD from AD and VaD with a pattern of bilateral anterior hypoperfusion. Tc-99m HMPAO SPECT may be used as an adjunct to clinical evaluation and CT but it is not a first-line test [50]. Variant 3: Suspected dementia with Lewy bodies. Initial imaging. Dementia with Lewy bodies (DLB) has been recognized as the second most prevalent neurodegenerative dementia in the elderly, causing up to 15% of cases [51]. It is a synucleinopathy with accumulation of insoluble alpha- Synuclein that aggregates to form Lewy bodies, which are the major pathological feature of the disease. To increase the accuracy of diagnosis of DLB, the latest diagnostic criteria incorporate findings from neuroimaging such as CT, MRI, SPECT, and PET [52]. Some authors have suggested a multimodality approach combining MRI and SPECT modalities as a useful and practical approach for differentiating DLB from AD [51]. CT Head Noncontrast CT head is a good first-line examination to exclude mimics like brain tumor or subdural hematoma. Relative preservation of the medial temporal lobe structures is also a supportive imaging biomarker according to the fourth consensus report of the DLB consortium [52]. CT with IV contrast or dual-phase CT imaging is not needed for initial evaluation. Dementia Amyloid PET/CT Brain DLB is also accompanied by amyloid deposition like AD, but overall, there is decreased uptake compared when with AD patients on amyloid imaging. Compared to Parkinson disease, DLB patients show a higher level of amyloid deposition [53]. At this time, amyloid PET/CT has very limited usefulness for diagnosis of DLB. Ioflupane SPECT or SPECT/CT Brain In the present guidelines, decreased dopamine transporter uptake is of the greatest importance among various neuroimaging findings and is listed as one of the suggestive features.