ZTE MR-based attenuation correction in brain FDG-PET/MR: performance in patients with cognitive impairment

• Published in: European radiology Vol. 30; no. 3; pp. 1770 - 1779
• Main Authors: Sgard, Brian, Khalifé, Maya, Bouchut, Arthur, Fernandez, Brice, Soret, Marine, Giron, Alain, Zaslavsky, Clara, Delso, Gaspar, Habert, Marie-Odile, Kas, Aurélie
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.03.2020; Springer Nature B.V; Springer Verlag
• Subjects: Adult; Aged; Aged, 80 and over; Alzheimer's disease; Attenuation; Bias; Brain; Brain - diagnostic imaging; Cerebellum; Cognitive ability; Cognitive Dysfunction - diagnosis; Computed tomography; Dementia; Dementia disorders; Diagnostic Radiology; Female; Fluorodeoxyglucose F18 - pharmacology; Humans; Image segmentation; Imaging; Impact analysis; Impairment; Internal Medicine; Interventional Radiology; Life Sciences; Magnetic resonance imaging; Magnetic Resonance Imaging - methods; Male; Medical imaging; Medicine; Medicine & Public Health; Metabolism; Middle Aged; Multimodal Imaging - methods; Neurodegenerative diseases; Neuroradiology; Nuclear Medicine; Occipital lobe; Positron emission; Positron emission tomography; Positron-Emission Tomography - methods; Radiology; Subgroups; Tomography; Ultrasound; glucose (FDG); Fluoro-2-deoxy; PET/MR; Neurodegenerative dementia; ZTE MRI; Attenuation correction; Fluoro-2-deoxy-D-glucose (FDG)
• ISSN: 0938-7994; 1432-1084; 1432-1084
• DOI: 10.1007/s00330-019-06514-z

Objective One of the main challenges of integrated PET/MR is to achieve an accurate PET attenuation correction (AC), especially in brain acquisition. Here, we evaluated an AC method based on zero echo time (ZTE) MRI, comparing it with the single-atlas AC method and CT-based AC, set as reference. Methods Fifty patients (70 ± 11 years old, 28 men) underwent FDG-PET/MR examination (SIGNA PET/MR 3.0 T, GE Healthcare) as part of the investigation of suspected dementia. They all had brain computed tomography (CT), 2-point LAVA-flex MRI (for atlas-based AC), and ZTE-MRI. Two AC methods were compared with CT-based AC (CTAC): one based on a single atlas, one based on ZTE segmentation. Impact on brain metabolism was evaluated using voxel and volumes of interest–based analyses. The impact of AC was also evaluated through comparisons between two subgroups of patients extracted from the whole population: 15 patients with mild cognitive impairment and normal metabolic pattern, and 22 others with metabolic pattern suggestive of Alzheimer disease, using SPM12 software. Results ZTE-AC yielded a lower bias (3.6 ± 3.2%) than the atlas method (4.5 ± 6.1%) and lowest interindividual (4.6% versus 6.8%) and inter-regional (1.4% versus 2.6%) variabilities. Atlas-AC resulted in metabolism overestimation in cortical regions near the vertex and cerebellum underestimation. ZTE-AC yielded a moderate metabolic underestimation mainly in the occipital cortex and cerebellum. Voxel-wise comparison between the two subgroups of patients showed that significant difference clusters had a slightly smaller size but similar locations with PET images corrected with ZTE-AC compared with those corrected with CT , whereas atlas-AC images showed a notable reduction of significant voxels. Conclusion ZTE-AC performed better than atlas-AC in detecting pathologic areas in suspected neurodegenerative dementia. Key Points • The ZTE-based AC improved the accuracy of the metabolism quantification in PET compared with the atlas-AC method. • The overall uptake bias was 21% lower when using ZTE-based AC compared with the atlas-AC method. • ZTE-AC performed better than atlas-AC in detecting pathologic areas in suspected neurodegenerative dementia.