DOI: 10.1007/s00259-018-4111-3Pages: 1-12

Amyloid imaging for differential diagnosis of dementia: incremental value compared to clinical diagnosis and [18F]FDG PET

1. University of Freiburg, Department of Psychiatry and Psychotherapy, Medical Center – University of Freiburg, Faculty of Medicine

2. University of Freiburg, Department of Nuclear Medicine, Medical Center – University of Freiburg, Faculty of Medicine

3. University of Freiburg, Center for Geriatrics and Gerontology Freiburg, Medical Center – University of Freiburg, Faculty of Medicine

4. University of Freiburg, Department of Neurology, Medical Center – University of Freiburg, Faculty of Medicine

5. University of Freiburg, Clinical Epidemiology, Institute of Medical Biometry and Medical Informatics

6. University Hospital Basel, Department of Orthopaedics and Traumatology

7. University Hospital Hamburg Eppendorf, Department of Diagnostic and Interventional Radiology and Nuclear Medicine

Correspondence to:
Sabine Hellwig
Tel: +49-761-270.65010
Email: sabine.hellwig@uniklinik-freiburg.de

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Abstract

Purpose

Cerebral beta-amyloid and regional glucose metabolism assessed by positron emission tomography (PET) are used as diagnostic biomarkers for Alzheimer’s disease (AD). The present study validates the incremental diagnostic value of amyloid PET in addition to clinical diagnosis and [18F]FDG PET in a real-life memory clinic population.

Methods

Of 138 consecutive patients with cognitive impairment who received combined [18F]FDG and [11C]PIB PET, 84 were diagnosed with major neurocognitive disorder (DSM-5) and included. Baseline clinical and [18F]FDG PET diagnoses were independently established with and without access to amyloid PET results and were dichotomized into AD or non-AD disorders. The incremental value of amyloid PET was evaluated in terms of: (1) the change in clinical and [18F]FDG PET diagnoses, (2) the change in agreement between clinical and [18F]FDG PET diagnoses, and (3) diagnostic accuracy using an interdisciplinary consensus diagnosis after an extended follow-up (2.4 ± 1.3 years after PET) as the reference.

Results

After disclosure of the amyloid PET results, clinical and [18F]FDG PET diagnoses changed in 23% and 18% of patients, respectively, and agreement between both ratings increased from 62% to 86% (p < 0.001). The accuracy of clinical and [18F]FDG PET diagnoses improved from 71% to 89% (p < 0.01) and from 76% to 94% (p < 0.001), respectively. The additional value of amyloid PET was rather uniform in relation to age at onset and consistency with appropriate use criteria.

Conclusion

Amyloid PET provides significant incremental diagnostic value beyond clinical and [18F]FDG PET diagnoses of AD. Given the high diagnostic accuracy of combined clinical and amyloid PET assessment, further studies are needed to clarify the role of an additional [18F]FDG PET scan in these patients.

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  • Accepted: Jul 10, 2018
  • Online: Aug 10, 2018

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