Cingulate island sign
The cingulate island sign is a highly specific radiological sign described in dementia with Lewy bodies.
It refers to the pattern of metabolism seen on FDG-PET in patients with dementia with Lewy bodies 1-3. On FDG-PET, there is occipital hypometabolism with relative sparing of the posterior cingulate cortex, thus creating the appearance of an 'island' of normal metabolism in the posterior cingulate region 1-3. The same pattern can also be appreciated in SPECT, whereby the posterior cingulate region has relatively normal perfusion while there is surrounding occipital hypoperfusion 2,3.
The cingulate island sign has been described as a useful radiological differentiator between dementia with Lewy bodies, which has the sign, and Alzheimer disease, in which the sign is not present 1-3. However, it has been found that as dementia with Lewy bodies progresses over time, the sign disappears, likely due to concomitant Alzheimer disease 3.
- 1. McKeith IG, Boeve BF, Dickson DW, Halliday G, Taylor JP, Weintraub D, Aarsland D, Galvin J, Attems J, Ballard CG, Bayston A, Beach TG, Blanc F, Bohnen N, Bonanni L, Bras J, Brundin P, Burn D, Chen-Plotkin A, Duda JE, El-Agnaf O, Feldman H, Ferman TJ, Ffytche D, Fujishiro H, Galasko D, Goldman JG, Gomperts SN, Graff-Radford NR, Honig LS, Iranzo A, Kantarci K, Kaufer D, Kukull W, Lee VMY, Leverenz JB, Lewis S, Lippa C, Lunde A, Masellis M, Masliah E, McLean P, Mollenhauer B, Montine TJ, Moreno E, Mori E, Murray M, O'Brien JT, Orimo S, Postuma RB, Ramaswamy S, Ross OA, Salmon DP, Singleton A, Taylor A, Thomas A, Tiraboschi P, Toledo JB, Trojanowski JQ, Tsuang D, Walker Z, Yamada M, Kosaka K. Diagnosis and management of dementia with Lewy bodies: Fourth consensus report of the DLB Consortium. (2017) Neurology. 89 (1): 88-100. doi:10.1212/WNL.0000000000004058 - Pubmed
- 2. Lim SM, Katsifis A, Villemagne VL, Best R, Jones G, Saling M, Bradshaw J, Merory J, Woodward M, Hopwood M, Rowe CC. The 18F-FDG PET cingulate island sign and comparison to 123I-beta-CIT SPECT for diagnosis of dementia with Lewy bodies. (2009) Journal of nuclear medicine : official publication, Society of Nuclear Medicine. 50 (10): 1638-45. doi:10.2967/jnumed.109.065870 - Pubmed
- 3. Iizuka T, Iizuka R, Kameyama M. Cingulate island sign temporally changes in dementia with Lewy bodies. Scientific Reports. 7 (1): 1. doi:10.1038/s41598-017-15263-2