Automatic correction of dental artifacts in PET/MRI

Area of Science:

• Medical Imaging
• Image Processing
• Radiological Physics

Background:

• Magnetic resonance (MR)-based attenuation correction in positron emission tomography/MR imaging (PET/MRI) is crucial for accurate quantitative analysis.
• Signal voids in MRIs due to dental fillings are erroneously segmented as air, leading to significant artifacts in the attenuation map.
• These artifacts compromise the accuracy of PET quantification in the head and neck region.

Purpose of the Study:

• To develop and validate a novel method for correcting artificial air regions caused by dental fillings in PET/MRI attenuation maps.
• To improve the accuracy of attenuation correction in PET/MRI by differentiating between true air cavities and artifactual regions.

Main Methods:

• An extension to an active contour algorithm was developed to delineate artifact contours using non-attenuation corrected PET and the original attenuation map.
• A combined approach using artifact region templates, active shape models, and k-nearest-neighbors was employed to differentiate artifacts from anatomical air.
• The method was evaluated on 25 [Formula: see text]-fluorodeoxyglucose PET/MR patient datasets.

Main Results:

• The proposed method successfully delineated the outer contour of artifacts connected to the background.
• The combined artifact differentiation approach effectively distinguished between dental filling artifacts and anatomical air regions.
• An average of [Formula: see text] of artifact areas were corrected, demonstrating significant improvement.

Conclusions:

• The developed method provides an effective solution for correcting dental filling-induced artifacts in PET/MRI attenuation correction.
• Accurate attenuation correction is vital for reliable quantitative PET imaging, especially in the presence of metallic implants.
• This technique has the potential to enhance diagnostic accuracy and reduce quantification errors in PET/MRI studies involving patients with dental work.