Comparison of diffusion weighted MRI parameters of mediastinal lymph nodes with PET/CT in lung cancer patients

Abstract

Objective: We have compared diffusion-weighted magnetic resonance imaging (DW-MRI) properties of mediastinal lymph nodes in lung cancer patients with positron emission tomography/computed tomography (PET/CT) findings. Patients and Methods: Twenty-one consecutive untreated patients with lung cancer were included. DW-MRI was performed on a 1,5T scanner with b values of 50, 500 and 1000. Additional MR imaging was performed for anatomical correlation. Results: A total of 47 lymph nodes were analyzed. While no correlation was found between minimum apparent diffusion coefficient (ADC) values (ADCmin) of lymph nodes and their maximum standardized uptake values (SUVmax) on PET/CT, ADCmin ratios of lymph nodes to main lesion (ADCmin Node/Lesion) (r = - 0.407; p = 0.005) and lymph node to cerebrospinal fluid (ADCmin Node/CSF) (r = - 0.364; p = 0.012) were correlated with SUVmax. Cutoff values for DW-MRI parameters were determined using ROC analysis. Six lymph nodes were histopathologically examined. Both methods correctly identified one metastatic and two metastasis negative lymph nodes, while staging one lymph node with granulomatous change as metastasis positive. Two metastasis negative lymph nodes, reported as suspicious on PET/CT, were correctly staged on DW-MRI. Conclusion: Our findings indicate that DW-MRI could be at least as valuable as PET/CT in mediastinal staging of patients with lung cancer.