DaTscan and brain perfusion SPECT in dementia with Lewy bodies

Objectives Dementia with Lewy Bodies (DLB) is the second most frequent neuropathology after Alzheimer’s disease. Its diagnosis is based on clinical specific symptoms (Mc Keith’s criteria) including fluctuating cognition, recurrent visual hallucinations and motor Parkinson’s features. However, extrapyramidal syndrome is not constant at the early diagnosis. The aim was to study the benefit of brain perfusion (BP) SPECT and DatScan association in suspected DLB patients.

Methods Thirty-three patients with suspected DLB (17M/16F) were included, mean age was 76 ys (range:60-87). Four patients were excluded after a 2-year follow-up, because of no matched clinical DLB criteria. After iv injection of 99m-Tc-ECD (750 MBq), BP SPECT imaging was performed in all patients. Thirty patients had DatScan after iv injection of 123-I-ioflupane (110 MBq). All studies were performed on Symbia T2 (Siemens) SPECT/CT gamma camera. In BP SPECT, occipital hypoperfusion was studied, as well as the correlation with clinical symptoms (visual hallucinations and extrapyramidal syndrome).

Results All included patients (29/33) showed clinical symptomatology (DLB criteria). Occipital hypoperfusion was found in 26/29 (89%) subjects in BP SPECT, whereas only 9/29 (31%) patients suffered from visual hallucinations. Eight of them (89%) had an occipital hypoperfusion in BP SPECT. DatScan was performed in 26/29 (89%) patients and all had positive findings. Ten of 26 (38%) DatScan patients showed no extrapyramidal syndrome. Three patients without DatScan exam presented clinically extrapyramidal syndrome.

Conclusions DatScan imaging is positive in all clinically diagnosed DLB patients and thus normal findings exclude suspected disease. Furthermore, while extrapyramidal symptomatology and visual hallucinations are not always presented, association of brain perfusion SPECT and DatScan could help early DLB detection