N staging of lung cancer patients with PET/MRI using a three-segment model attenuation correction algorithm: initial...

Area of Science:

• Nuclear Medicine
• Radiology
• Oncology

Background:

• Accurate staging of lung cancer, particularly lymph node (LN) involvement, is critical for treatment planning.
• Positron emission tomography/computed tomography (PET/CT) is a standard imaging modality for lung cancer staging.
• Evaluating novel imaging techniques like PET/MRI is essential for improving diagnostic accuracy and patient management.

Purpose of the Study:

• To assess the performance of PET/MRI compared to PET/CT in detecting lymph node metastases in lung cancer patients.
• To evaluate the accuracy of standardized uptake value maximum (SUVmax) measurements using PET/MRI at tissue interfaces with varying attenuation.
• To determine the interobserver agreement and diagnostic performance of PET/MRI for N staging in lung cancer.

Main Methods:

• Eleven lung cancer patients underwent both PET/CT and PET/MRI scans.
• Four experienced readers independently determined the N stage from each imaging method in a blinded, randomized manner.
• SUVmax of FDG-avid LNs was measured, and results were analyzed for interobserver agreement, SUVmax correlation, and diagnostic performance, utilizing a three-segment model for attenuation correction.

Main Results:

• High interobserver agreement was observed for PET/CT (κ=0.86) and substantial agreement for PET/MRI (κ=0.70).
• A strong positive correlation (Spearman's ρ=0.93, P<0.001) was found in SUVmax measurements between PET/CT and PET/MRI.
• The diagnostic performance of PET/MRI was slightly inferior to PET/CT, but this difference was not statistically significant (P>0.05).

Conclusions:

• PET/MRI with a three-segment model for attenuation correction demonstrates performance comparable to PET/CT for lymph node staging in lung cancer.
• The technique shows strong parallels with PET/CT regarding SUVmax measurements, interobserver agreement, and diagnostic accuracy.
• PET/MRI is a reliable tool for assessing the mediastinum in lung cancer staging, with substantial interobserver agreement.