Abstract
ObjectiveTo determine whether occipital and cingulate hypometabolism is being under-reported or missed on 18-fluorodeoxyglucose positron emission tomography (FDG-PET) CT scans in patients with Dementia with Lewy Bodies (DLB).BackgroundRecent studies have reported higher sensitivity and specificity for occipital and cingulate hypometabolism on FDG-PET of DLB patients.MethodsThis retrospective chart review looked at regions of interest (ROI’s) in FDG-PET CT scan reports in 35 consecutive patients with a clinical diagnosis of probable, possible, or definite DLB as defined by the latest DLB Consortium Report. ROI’s consisting of glucose hypometabolism in frontal, parietal, temporal, occipital, and cingulate areas were tabulated and charted separately by the authors from the reports. A blinded Nuclear medicine physician read the images independently and marked ROI’s separately. A Cohen’s Kappa coefficient statistic was calculated to determine agreement between the reports and the blinded reads.ResultsOn the radiology reports, 25.71% and 17.14% of patients reported occipital and cingulate hypometabolism respectively. Independent reads demonstrated significant disagreement with the proportion of occipital and cingulate hypometabolism being reported on initial reads: 91.43% and 85.71% respectively. Cohen’s Kappa statistic determinations demonstrated significant agreement only with parietal hypometabolism (p<0.05).ConclusionOccipital and cingulate hypometabolism is under-reported and missed frequently on clinical interpretations of FDG-PET scans of patients with DLB, but the frequency of hypometabolism is even higher than previously reported. Further studies with more statistical power and receiver operating characteristic analyses are needed to delineate the sensitivity and specificity of these in vivo biomarkers.
Highlights
Dementia with Lewy Bodies (DLB) is the second-most common cause of dementia in North America behind Alzheimer’s disease, and is characterized by cognitive, motor, and neuropsychiatric disturbances that usually follow a fluctuating, progressive course [1]
Independent reads demonstrated significant disagreement with the proportion of occipital and cingulate hypometabolism being reported on initial reads: 91.43% and 85.71% respectively
Seventeen (17) patients, comprising 48.57% of our patient population, carried a diagnosis of definite DLB, while 16 (45.71%) patients carried a diagnosis of probable DLB
Summary
Dementia with Lewy Bodies (DLB) is the second-most common cause of dementia in North America behind Alzheimer’s disease, and is characterized by cognitive, motor, and neuropsychiatric disturbances that usually follow a fluctuating, progressive course [1]. Albin et al [4] looked at 6 patients with pathologically-confirmed DLB and found significant occipital and primary visual cortex hypometabolism. The largest multi-center trial to date, one led by Mosconi et al [7] looked at a total of 548 patients including both healthy controls and dementia patients, 27 of them carrying a definite DLB diagnosis as defined by the McKeith Consensus Criteria, and found that occipital hypometabolism had a 71% specificity for DLB. Fujishiro et al [9] studied patients with occipital hypometabolism regardless of comorbid dementia and found that FDG-PET findings in the primary visual cortex can be associated with conditions other than DLB such as REM-sleep behavioral disorder and Parkinson’s Disease. Recent studies have reported higher sensitivity and specificity for occipital and cingulate hypometabolism on FDG-PET of DLB patients
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