Caracterização de linfadenopatia mediastinal por por meio de ressonância nuclear magnética

Abstract

Introduction: Several pathological conditions affect the lymph nodes, such as presence of infection, inflammation, or neoplasia. Differentiating benign diseases from malignant neoplasms is crucial. The aim of this study is to evaluate the use of nuclear magnetic resonance imaging for the characterization of thoracic lymphadenopathy. Methods: First, a systematic review was conducted evaluating the studies that used diffusion-weighted MRI to differentiate benign from malignant diseases in mediastinal lymph nodes. A meta-analysis was conducted with the inclusion of six studies. In addition, an original study was conducted with the inclusion of 47 patients, differentiating the findings of nuclear magnetic resonance between two common causes of mediastinal lymphadenopathy - sarcoidosis and lymphoma. Results: The meta-analysis included 356 lymph nodes studied from 214 patients. With the use of diffusion-weighted imaging – a nuclear magnetic resonance imaging technique - the pooled sensitivity and specificity in differentiating benign and malignant lymph nodes was 92% (95% CI: 71%, 98%) and 93% (95% CI: 79%, 98%), respectively. In the study of lymphoma and sarcoidosis differentiation, among the 47 patients included, 47% (23/47) were diagnosed with sarcoidosis and 53% (24/47) with lymphoma. There was no significant difference between signal intensity in T1, T2 sequences, location or size of nodules between sarcoidosis and lymphoma. The T2 ratio of lymph nodes in sarcoidosis [5.0 (3.7-5.3)] was significantly (P = 0.009) lower than that of lymph nodes in the lymphoma group [8.3 (4.9-11, 9)]. The diffusion of lymph nodes in lymphoma [22 (19-54)] was significantly (P = 0.003) less than that of lymph nodes in sarcoidosis [58 (24-96)]. The ADC of lymphoma lymph nodes [993 ± 508] was significantly (P = 0.002) lower than that of lymph nodes with sarcoidosis [1668 ± 732]. Conclusion: Magnetic resonance imaging is a useful tool in the characterization of mediastinal lymph nodes and its use in differentiating between benign and malignant lymphadenopathies is justified.