The ¹⁸F-FDG PET Cingulate Island Sign and Comparison to ¹²³I-β-CIT SPECT for Diagnosis of Dementia with Lewy Bodies

Abstract

Neuroimaging is increasingly used to supplement the clinical diagnosis of dementia with Lewy bodies (DLB) by showing reduced occipital metabolism and perfusion and reduced striatal dopaminergic innervation. We aimed to optimize the interpretation of 18 F-FDG PET images for differentiating DLB from Alzheimer disease (AD) and to compare the results with dopamine transporter imaging using 123 I-b-carbomethoxy-3ß-(4-iodophenyl)-tropane ( 123 I-b-CIT) SPECT. Methods: Fourteen subjects with a clinical diagnosis of DLB and 10 with AD underwent both 18 F-FDG PET and 123 I-b-CIT SPECT. Four DLB and 1 AD diagnoses were subsequently confirmed at autopsy. Diagnostic accuracy was calculated for visual interpretation by 3 readers of standard 3-plane and stereotactic surface projection 18 F-FDG PET images, receiver-operating-characteristic analysis of regional 18 F-FDG uptake, and a cutoff value for the striatal-to-occipital binding ratio of b-CIT defined by receiver-operating-characteristic analysis. Results: Visual interpretation of 3-plane 18 F-FDG PET images had a sensitivity of 83% and specificity of 93% for DLB, slightly higher than the results with the stereotactic surface projection images. Regionally, hypometabolism in the lateral occipital cortex had the highest sensitivity (88%), but relative preservation of the mid or posterior cingulate gyrus (cingulate island sign) had the highest specificity (100%). Region-of-interest analysis revealed that occipital hypometabolism and relative preservation of the posterior cingulate both had a sensitivity of 77% and specificity of 80%. b-CIT achieved 100% accuracy and greater effect size than did 18 F-FDG PET (Cohen d 5 4.1 vs. 1.9). Conclusion: Both 18 F-FDG PET and 123 I-b-CIT SPECT appear useful for the diagnosis of DLB, although the latter provides more robust results. The cingulate island sign may enhance the specificity of 18 F-FDG PET.

Dementia with Lewy bodies

“…12 The cingulate island sign (CIS), a term referring to sparing of the posterior cingulate relative to the precuneus and cuneus, has been proposed as an FDG-PET imaging feature of DLB. 13,14 Although the CIS performed well in differentiating clinically diagnosed cases of AD from DLB, few cases underwent autopsy. 14 Our objective was to investigate the clinical and pathologic associations of the CIS using PiB-PET for the assessment of Ab pathology and Braak staging of the NFT pathology at autopsy.…”

“…13,14 Although the CIS performed well in differentiating clinically diagnosed cases of AD from DLB, few cases underwent autopsy. 14 Our objective was to investigate the clinical and pathologic associations of the CIS using PiB-PET for the assessment of Ab pathology and Braak staging of the NFT pathology at autopsy.…”

Brain 18F-FDG, 18F-Florbetaben PET/CT, 123I-FP-CIT SPECT and Cardiac 123I-MIBG Imaging for Diagnosis of a "Cerebral Type" of Lewy Body Disease

“…Indeed, DLB is probable here because the patient showed two of the three core features of DLB: fluctuating cognition and alertness, recurrent visual hallucinations, but no parkinsonism [2]. The preservation of metabolic activity in the cingulate gyrus (cingulate island sign) has been described as being characteristic for DLB (100 % specific; sensitivity 62-82 %) [4].…”

“…18 F-FDG PET/CT ( Fig. 1-a, b) showed hypometabolism in the posterior associative cortex including the occipital cortex (white arrows), while amygdalo-hippocampal complexes and posterior cingulate cortex were preserved (black arrows), a pattern suggesting DLB [3,4]. AD was ruled out by a normal 18 F-florbetaben PET/CT, showing no ß-amyloid deposition in the grey-matter (Fig.…”

Nuclear Medicine Applications in Movement Disorders

“…LCD ile AH'nın ayırıcı tanısında beyin FDG PET görüntüleme bulgularından yararlanılabilir (56,59,60,61,62). LCD'da AH'nda gözlenen temporoparietal hipometabolizmaya ek olarak oksipital de hipometabolizma bulgusu olması (56,59,62) ve posterior singulat korteks metabolizmasının kuneus ile prekuneus metabolizmasına göre daha çok korunmuş olmasından kaynaklanan "singulat adası bulgusu" LCD'nin AH'sinden ayırt edilmesini sağlayan özelliklerdir (62).…”