Sequential dynamic PET and dynamic MR imaging in N-staging of lung cancer patients

Purpose:

For therapy stratifications, staging of lung cancer is typically performed with FDG-PET/CT. In the context of new established integrated PET/MR-scanners, the combination of well established dynamic contrast enhanced (DCE) MRI imaging with dynamic PET might be an upcoming imaging modality. In order to evaluate potential perfusion changes between benign and malignant lymph nodes in lung cancer patients, DCE MRI was correlated to microcirculatory and sub cellular dynamic parameters in FDG-PET/CT.

Materials and Methods:

According to the clinical routine, a total number of 14 patients with lung cancer were examined sequentially with FDG-PET/CT (Siemens Biograph 6) and DCE MRI (Gadovist®, Bayer, Germany; Siemens Magnetom Aera, 1.5T) prior to surgery. Findings were correlated to the histological gold standard.

Results:

14 lymph nodes (six malignant, eight benign) could clearly be histological analyzed and were correlated with findings in MRI and PET/CT. In DCE MRI, malignant lymph nodes showed early and generally increased perfusion values compared to benign ones, with typical signs for washout 60 seconds after contrast injection. Benign lymph node reached the typically plateau phase after 60 seconds with steady state during the first 180 seconds.

This correlated well with microcirculatory and sub cellular parameters in dynamic PET according to a two compartment model, especially with changes in k3 and k4.

Conclusion:

The sub cellular parameters k3 and k4 in dynamic PET are correlating with changes in DCE MRI, indicating k3 and k4 as potential surrogate parameter for malignant lymph node infiltration in lung cancer patients.

*Presenting author