Magnetic resonance imaging apparent diffusion coefficient in lymphomas and its dependence on a number of technical and clinical factors

Abstract

The purpose of this study was to determine the value of apparent diffusion coefficient (ADC) in various morphological variants of lymphomas, to study dependence of ADC on the anatomical location of lesions and technical scanning parameters to establish the usefulness in differentiating normal and involved lymph nodes (LN).Whole body MRI with diffusion-weighted imaging (DWI) was performed in 209 patients with lymphoma before treatment. A target LN was selected and ADC determined in each patient.The ADC value does not depend on the use of the parallel imaging technique (p= 0.56), higher when using built-in compared to superficial coil (p< 0.0001), higher when using respiratory triggering than free breathing (p< 0.02). The highest ADC values (х10-3mm2/s) were obtained in the involved LN of the lung hilar (1.429 ± 0.396) and mediastinum (1.338 ± 0.313), lower values (p< 0.01) - in the LN of the abdomen (1.011 ± 0.298), axillary (0.840 ± 0.196), neck (0.834 ± 0.259), inguinal (0.753 ± 0.128) and iliac (0.738 ± 0.129). Depending on the morphological variant of lymphoma, the highest ADC value was obtained in Hodgkin lymphoma - 1.168 ± 0.372 (p< 0.0002). ADC in diffuse large B-cell non-Hodgkin lymphoma was 0.951 ± 0.320, indolent non-Hodgkin lymphomas - 0.756 ± 0.246, mantle zone non-Hodgkin lymphoma - 0.759 ± 0.211.In conclusion, DWI in lymphoma should be performed using surface coil, parallel imaging, and free breathing. Statistically significant differences in ADC were found depending on the anatomical location of the lesions and the morphological variant of lymphoma. Given the dependence of ADC on various technical and clinical factors, it is not possible to establish a single threshold value for differentiating involved and normal LN. The use of the LN size criterion for this purpose is the most optimal in lymphoma.