Comparative evaluation of MR-based partial-volume correction schemes for PET.

Area of Science:

• Neuroimaging
• Medical Physics

Background:

• Quantitative Positron Emission Tomography (PET) measurements are affected by partial-volume averaging, which limits spatial resolution.
• This averaging occurs among neighboring tissues with differing tracer concentrations, impacting cerebral blood flow, glucose metabolism, and neuroreceptor binding.

Purpose of the Study:

• To compare two Magnetic Resonance (MR)-based approaches for partial-volume correction of PET images.
• To evaluate the impact of various error sources on these correction methods.
• To assess the utility of these methods in studies of aging and neurodegenerative diseases.

Main Methods:

• Simulations and a multicompartment phantom were used to compare a two-compartment and a three-compartment MR-based partial-volume correction method.
• The two-compartment method corrects for cerebrospinal fluid (CSF) effects.
• The three-compartment method corrects for CSF and gray/white matter partial-volume averaging.

Main Results:

• The three-compartment method achieved high accuracy in simulations, with 100% gray matter recovery.
• However, the three-compartment method was more sensitive to errors like misregistration, resolution mismatch, segmentation errors, and white matter heterogeneity.
• The two-compartment method demonstrated better robustness against these errors.

Conclusions:

• The two-compartment approach is recommended for comparative PET studies due to its robustness.
• The three-compartment algorithm is suitable for absolute quantitative PET measures when accuracy is paramount and errors can be minimized.