Towards quantitative PET/MRI: a review of MR-based attenuation correction techniques

Area of Science:

• Medical Imaging
• Nuclear Medicine
• Biophysics

Background:

• Positron Emission Tomography (PET) is a quantitative imaging technique requiring attenuation correction for accurate data.
• Traditional PET/CT systems use CT transmission scans for attenuation correction.
• Combined PET/MRI offers an alternative but lacks CT-like transmission sources.

Purpose of the Study:

• To review existing methods for MR-based attenuation correction (MR-AC) in PET/MRI.
• To discuss the challenges and potential of MR-AC for clinical implementation.
• To explore MR-AC strategies for both brain and torso PET/MRI.

Main Methods:

• Review of current MR-AC algorithms and strategies.
• Discussion of approaches utilizing complementary MR and transmission images.
• Exploration of template-based MR-AC methods.

Main Results:

• MR-AC is an evolving field with promising template-based strategies.
• MR-AC algorithms have been developed for both brain and torso PET/MRI.
• Current MR-AC methods often require complementary MR and transmission data or templates.

Conclusions:

• MR-AC is a developing technology with potential for quantitative PET/MRI.
• Template-based MR-AC shows promise for broad applicability.
• Further research is needed to achieve fully automatic and clinically viable MR-AC, including motion and partial volume correction.