Impact of tissue photon attenuation in small animal cardiac PET imaging

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• 作者：Nobuyuki Hayakawa^a ; ^b ; Tomohiko Yamane^a ; ^b ; Anahi-Paula Arias-Loza^b ; ^c ; Tetsuya Shinaji^a ; ^b ; Hiroshi Wakabayashi^a ; ^b ; Constantin Lapa^a ; Rudolf A. Werner^a ; ^b ; Mehrbod S. Javadi^d ; Theo Pelzer^c ; Takahiro Higuchi^a ; ^b ; ^{thiguchi@me.com}
• 关键词：Tissue photon attenuation ; Attenuation correction ; Small animal ; Cardiac PET
• 刊名：International Journal of Cardiology
• 出版年：2017
• 出版时间：15 January 2017
• 年：2017
• 卷：227
• 期：Complete
• 页码：257-260
• 全文大小：666 K
• 卷排序：227

文摘

Tissue photon attenuation is one of the essential artifacts requiring correction in clinical cardiac positron emission tomography (PET) imaging. However, due to small body size its impact on diagnostic accuracy in small rodents is considered to be limited or even ignorable. The present cardiac PET study compares lean and obese rats to determine the influence of tissue attenuation on quantitative assessment as well as regional tracer distribution.MethodsA dedicated small animal PET system equipped with a 57Co rotating source for transmission was used. To assess the impact of tissue attenuation in rats with different body sizes, cardiac 18F­FDG -PET studies for Zucker diabetic fatty rats (obese rats) and Zucker lean rats (lean rats) were performed. The radiotracer activity reduction by attenuation was compared between the two groups. Regional tracer distribution calculated with and without attenuation correction was also assessed.ResultsThe chest diameter was significantly longer in obese than in lean rats (5.6 ± 0.3 cm in obese and 4.5 ± 0.2 cm in lean rats, p < 0.0001). Whereas the activity reduction by attenuation was significantly greater in obese than in lean rats (44.1 ± 2.5% and 5.1 ± 3.1%, p < 0.0001), the regional variation of tissue attenuation among the ventricular walls was minimal in both lean (p = 0.73) and obese rats (p = 0.65).ConclusionAttenuation correction is indispensable for accurate comparison of cardiac tracer activity between animals with different body size, whereas it can be omitted for evaluation of regional tracer distribution.