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Magnetic Resonance Materials in Physics, Biology and Medicine

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01.02.2013 | Research Article

Evaluation of an attenuation correction method for PET/MR imaging of the head based on substitute CT images

verfasst von: Anne Larsson, Adam Johansson, Jan Axelsson, Tufve Nyholm, Thomas Asklund, Katrine Riklund, Mikael Karlsson

Erschienen in: Magnetic Resonance Materials in Physics, Biology and Medicine | Ausgabe 1/2013

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Abstract

Object

The aim of this study was to evaluate MR-based attenuation correction of PET emission data of the head, based on a previously described technique that calculates substitute CT (sCT) images from a set of MR images.

Materials and methods

Images from eight patients, examined with ¹⁸F-FLT PET/CT and MRI, were included. sCT images were calculated and co-registered to the corresponding CT images, and transferred to the PET/CT scanner for reconstruction. The new reconstructions were then compared with the originals. The effect of replacing bone with soft tissue in the sCT-images was also evaluated.

Results

The average relative difference between the sCT-corrected PET images and the CT-corrected PET images was 1.6 % for the head and 1.9 % for the brain. The average standard deviations of the relative differences within the head were relatively high, at 13.2 %, primarily because of large differences in the nasal septa region. For the brain, the average standard deviation was lower, 4.1 %. The global average difference in the head when replacing bone with soft tissue was 11 %.

Conclusion

The method presented here has a high rate of accuracy, but high-precision quantitative imaging of the nasal septa region is not possible at the moment.

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Titel: Evaluation of an attenuation correction method for PET/MR imaging of the head based on substitute CT images
verfasst von: Anne Larsson
Adam Johansson
Jan Axelsson
Tufve Nyholm
Thomas Asklund
Katrine Riklund
Mikael Karlsson
Publikationsdatum: 01.02.2013
Verlag: Springer-Verlag
Erschienen in: Magnetic Resonance Materials in Physics, Biology and Medicine / Ausgabe 1/2013
Print ISSN: 0968-5243
Elektronische ISSN: 1352-8661
DOI: https://doi.org/10.1007/s10334-012-0339-2

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Evaluation of an attenuation correction method for PET/MR imaging of the head based on substitute CT images