Characterization of mediastinal lymphadenopathy with diffusion-weighted imaging.
OBJECTIVE
To predict malignancy of mediastinal lymphadenopathy with diffusion-weighted imaging.


METHODS
A prospective study was conducted on 35 patients with mediastinal lymphadenopathy (28 malignant and seven benign nodes). They underwent echoplanar diffusion-weighted magnetic resonance imaging of the mediastinum with b-factors of 0, 300 and 600 s/mm(2). The apparent diffusion coefficient (ADC) values of the mediastinal lymph nodes were calculated. The ADC values were correlated with the biopsy results and statistical analysis was done. A value of P<.05 was considered significant.


RESULTS
The mean ADC value of malignant mediastinal lymphadenopathy (1.06±0.3×10(-3) mm(2)/s) was significantly lower (P=.001) than that of benign lymphadenopathy (2.39±0.7×10(-3) mm(2)/s). There was an insignificant difference in the ADC values between metastatic and lymphomatous mediastinal lymph nodes (P=.32) as well as within benign nodes (P=.07). When an ADC value of 1.85×10(-3) mm(2)/s was used as a threshold value for differentiating malignant mediastinal nodes from benign nodes, the best results were obtained with an accuracy of 83.9%, a sensitivity of 96.4%, a specificity of 71.4%, a negative predictive value of 95.2% and a positive predictive value of 77.1%. The area under the curve was 0.98.


CONCLUSIONS
Diffusion weighted magnetic resonance imaging is a promising noninvasive imaging modality that can be used for characterization of mediastinal lymphadenopathy and differentiation of malignant from benign mediastinal lymph nodes.
Abdel Razek
Ahmed Abdel Khalek
AA
Department of Diagnostic Radiology, Mansoura Faculty of Medicine, 3551 Mansoura, Egypt. arazek@mans.eun.eg
Elkammary
Sahar
S
Elmorsy
Ahmed Saad
AS
Elshafey
Mohsen
M
Elhadedy
Tamer
T
D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology*; D008206:Lymphatic Diseases / Q000175:diagnosis*; D008297:Male; D008477:Mediastinal Diseases / Q000175:diagnosis*; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D055815:Young Adult