PURPOSE

Differential diagnosis between dementia with Lewy bodies (DLB) and other neurodegenerative diseases with cognitive impairment represents a clinical challenge. Due to the overlapping of symptoms, the clinical diagnosis can be modified during the prolonged follow-up of these diseases. The purpose of this study was to assess the ability of cardiac metaiodobenzylguanidine (MIBG) imaging for early identification of DLB.

MATERIALS AND METHODS

Since January 2003, all patients with neurodegenerative diseases with cognitive impairment at their first visit at the Memory Unit and clinical criteria of DLB were consecutively recruited and underwent a cardiac (123)I-MIBG study. The heart-to-mediastinum ratio (HMR) and the washout rate (WR) of cardiac MIBG uptake were obtained.

RESULTS

Sixty-five patients were included. After a clinical follow-up of 4 years, the progress of the disease procured a definite diagnosis in 44 (68%) patients: 19 DLB, 12 Alzheimer disease (AD), and 13 other neurodegenerative diseases with cognitive impairment. HMR was significantly decreased in DLB with respect to the other neurodegenerative diseases. WR was only significantly different between DLB and AD. The HMR cut off point of 1.36 differentiated DLB from the other dementias with a sensitivity of 94% and a specificity of 96% with an accuracy of 95%.

CONCLUSIONS

Cardiac MIBG imaging performed at the time of the first clinical diagnosis of DLB can help early clinical identification or exclusion of this disease.