Cervical lymphadenopathy in tularemia: the role of diffusion-weighted magnetic resonance imaging in differentiating lymphadenopathies due to metastatic tumors

Abstract

To evaluate the role of diffusion-weighted magnetic resonance imaging (DW-MRI) in differentiating enlarged cervical lymph nodes due to tularemia and metastatic tumors. Methods: We evaluated 59 patients with cervical lymphadenopathy (LAP) (32 patients with tularemia, 27 patients with metastatic tumors), retrospectively. We analyzed contrast enhancement patterns of LAP in postcontrast fat sat T1WI. We evaluated T2, DWI, and ADC signals of LAP in a 5-point scale system. Moreover, the mean ADC values of solid and necrotic LAP in both groups were quantitatively measured and compared statistically. Receiver operating characteristic curves of quantitative ADC values were obtained to determine the diagnostic performance. Results: There was no difference between solid and necrotic LAP enhancement patterns in two groups. Solid LAP and peripheral parts of necrotic LAP showed diffusion restriction, whereas central parts necrotic LAP had high ADC and low DWI signal in both tularemia and metastatic groups. Signal characteristics were similar in two groups. In solid LAP, there was no significant difference between ADC values in two groups. In necrotic LAP, total, central, and peripheral quantitative ADC measurements were higher in the metastatic group than in the tularemia group. Conclusions: Conventional MRI findings were not sufficient to differentiate metastatic LAP from tularemia. DW-MRI was not helpful in solid LAP; however, ADC values of metastatic necrotic LAP were significantly higher than tularemia. Microagglutination tests would be useful for differentiation; however, DW-MRI might also be useful for differentiation and may expedite the diagnosis.