Importance of attenuation correction in PET/MR image quantification: Methods and applications

Area of Science:

• Medical Imaging
• Nuclear Medicine
• Radiology

Background:

• Accurate attenuation correction (AC) maps are essential for quantitative positron emission tomography/magnetic resonance (PET/MR) imaging.
• Unlike CT, MR signal intensity does not directly correlate with PET attenuation coefficients (μ), posing a challenge for MR-based AC map generation.
• Ignoring bone in MR-based AC maps leads to biased standardized uptake value (SUV) calculations.

Purpose of the Study:

• To review existing MR-based AC methods for PET/MR imaging.
• To discuss the challenges encountered in translating these methods into full-body applications.
• To highlight the need for standardization and clinical validation of AC methods for widespread clinical adoption.

Main Methods:

• Review of literature on MR-based attenuation correction techniques for PET/MR.
• Analysis of challenges in implementing these methods in clinical practice.
• Discussion of the role of the PET/MR community and vendors in standardization.

Main Results:

• MR-based AC methods have advanced significantly, with accuracy no longer a primary limitation in research settings.
• Many current methods face hurdles in clinical validation and practical implementation.
• Standardization and vendor accessibility are critical for integrating advanced AC methods into clinical workflows.

Conclusions:

• While research settings have overcome AC accuracy limitations, clinical translation of MR-based AC methods remains challenging.
• Insufficient clinical validation and implementation difficulties hinder widespread adoption.
• Collaboration within the PET/MR community and vendor support are vital for standardizing and implementing effective AC methods in clinical practice.