Visual detection of regional brain hypometabolism in cognitively impaired patients is independent of positron emission tomography-magnetic resonance attenuation correction method

Ana Franceschi; Valentino Abballe; Roy Raad; Aaron Nelson; Kimberly Jackson; James Babb; Thomas Vahle; Matthias Fenchel; Yiqiang Zhan; Gerardo Valadez; Timothy Shepherd; Kent Friedman

doi:10.4103/wjnm.WJNM_61_17

World Journal of Nuclear Medicine, Table of Contents

CC BY-NC-ND 4.0 · World J Nucl Med 2018; 17(03): 188-194
DOI: 10.4103/wjnm.WJNM_61_17

Original article

Visual detection of regional brain hypometabolism in cognitively impaired patients is independent of positron emission tomography-magnetic resonance attenuation correction method

Ana Franceschi

¹Department of Radiology, New York University Medical Center, New York, NY

,

Valentino Abballe

¹Department of Radiology, New York University Medical Center, New York, NY

,

Roy Raad

¹Department of Radiology, New York University Medical Center, New York, NY

,

Aaron Nelson

²MIM Software Inc., Cleveland, OH

,

Kimberly Jackson

¹Department of Radiology, New York University Medical Center, New York, NY

,

James Babb

¹Department of Radiology, New York University Medical Center, New York, NY

,

Thomas Vahle

³Siemens Healthcare Gmbh, Erlangen, Germany

,

Matthias Fenchel

³Siemens Healthcare Gmbh, Erlangen, Germany

,

Yiqiang Zhan

⁴Siemens Medical Solutions, Malvern, PA, USA

,

Gerardo Valadez

⁴Siemens Medical Solutions, Malvern, PA, USA

,

Timothy Shepherd

¹Department of Radiology, New York University Medical Center, New York, NY

⁵Center for Advanced Imaging Innovation and Research, New York, NY

,

Kent Friedman

¹Department of Radiology, New York University Medical Center, New York, NY

› Author Affiliations

Abstract

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Fluorodeoxyglucose (FDG) positron emission tomography-magnetic resonance (PET/MR) is useful for the evaluation of cognitively-impaired patients. This study aims to assess two different attenuation correction (AC) methods (Dixon-MR and atlas-based) versus index-standard computed tomography (CT) AC for the visual interpretation of regional hypometabolism in patients with cognitive impairment. Two board-certified nuclear medicine physicians blindly scored brain region FDG hypometabolism as normal versus hypometabolic using two-dimensional (2D) and 3D FDG PET/MR images generated by MIM software. Regions were quantitatively assessed as normal versus mildly, moderately, or severely hypometabolic. Hypometabolism scores obtained using the different methods of AC were compared, and interreader, as well as intra-reader agreement, was assessed. Regional hypometabolism versus normal metabolism was correctly classified in 16 patients on atlas-based and Dixon-based AC map PET reconstructions (vs. CT reference AC) for 94% (90%–96% confidence interval [CI]) and 93% (89%–96% CI) of scored regions, respectively. The averaged sensitivity/specificity for detection of any regional hypometabolism was 95%/94% (P = 0.669) and 90%/91% (P = 0.937) for atlas-based and Dixon-based AC maps. Interreader agreement for detection of regional hypometabolism was high, with similar outcome assessments when using atlas- and Dixon-corrected PET data in 93% (Κ =0.82) and 93% (Κ =0.84) of regions, respectively. Intrareader agreement for detection of regional hypometabolism was high, with concordant outcome assessments when using atlas- and Dixon-corrected data in 93%/92% (Κ =0.79) and 92/93% (Κ =0.78). Despite the quantitative advantages of atlas-based AC in brain PET/MR, routine clinical Dixon AC yields comparable visual ratings of regional hypometabolism in the evaluation of cognitively impaired patients undergoing brain PET/MR and is similar in performance to CT-based AC. Therefore, Dixon AC is acceptable for the routine clinical evaluation of dementia syndromes.

Keywords

Attenuation correction - brain - dementia - Dixon - positron emission tomography-magnetic resonance

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