Sci—Fri AM: Imaging — 06: The role of body mass and gender in atlas construction for attenuation correction in PET/MRI

J. Patrick, H. Marshall, E. Sabondjian, J. Butler, I. Rachinsky, T. Thompson, J. Théberge, F. Prato, R. Stodilka

Research output: Contribution to journalArticlepeer-review

Abstract

Attenuation correction (AC) in PET/MRI is difficult as there is no clear relationship between MR signal and 511 keV attenuation coefficients (μ) as there is with CT. One approach is to register a pre‐defined atlas of μ to the PET/MRI for AC. However, the design of the atlas may strongly influence the quantitative accuracy of the AC. Here we compare 3 different atlas design approaches and evaluate their performance in an oncology patient population. The 3 strategies were: use of BMI‐dependent atlases; use of gender‐dependent atlases, and use of a gender‐ and sex‐independent atlas. Seventeen patients were imaged with FDG PET/CT and subsequently scanned with 3T MRI. MR and PET/CT images were coregistered, CT scans converted to μ‐maps, and the resulting MRI/μ‐map paired data were used to construct 6 atlases: averaged male and female atlases, averaged BMI‐specific atlases (obese >30, overweight 25–29.9, Normal 18.5–24.9), and a single atlas comprised of all patients averaged together. The atlases were then used for PET AC for patients not included in the construction of the atlas in a leave‐one‐out manner. Resulting PET images were compared to each other and to the gold‐standard CT‐based PET reconstructions across all voxels and tissue‐specific regions (soft‐tissue, bone, lung). Sex‐specific atlases yielded best results (average relative percent error over the 3 VOIs = 0.4509) & BMI‐based atlases yielded highest average relative percent error at 0.9340. In all cases, highest errors were in the VOIs located in the livers.

Original languageEnglish
Pages (from-to)4641
Number of pages1
JournalMedical Physics
Volume39
Issue number7
DOIs
StatePublished - 1 Jan 2012
Externally publishedYes

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