Differential diagnosis of axillary inflammatory and metastatic lymph nodes in rabbit models by using diffusion-weighted imaging: compared with conventional magnetic resonance imaging.
OBJECTIVE
This experiment aims to determine the diagnostic value of diffusion-weighted imaging (DWI) in the differentiation of axillary inflammatory lymph nodes from metastatic lymph nodes in rabbit models in comparison with conventional magnetic resonance imaging (MRI).


METHODS
Conventional MRI and DWI were performed at 4 weeks after successful inoculation into the forty female New Zealand white rabbits' mammary glands. The size-based and signal-intensity-based criteria and the relative apparent diffusion coefficient (rADC) value were compared between the axillary inflammatory lymph nodes and metastatic lymph nodes, with histopathological findings as the reference standard. Receiver operating characteristic (ROC) curve analysis was performed to evaluate the diagnostic performance of the aforementioned criteria and rADC value in differentiating the axillary inflammatory lymph nodes from metastatic lymph nodes.


RESULTS
Thirty-two axillary inflammatory lymph nodes and 46 metastatic ones were successfully isolated and taken into pathological analysis. The differences of the aforementioned criteria between the two groups were not statistically significant (p > 0.05). However, the rADC value of the inflammatory lymph nodes (0.9 ± 0.14) was higher than that of metastatic ones (0.7 ± 0.18), with significant difference (p = 0.016). When the rADC value was chosen as 0.80, the area under the ROC curve is greater than all other criteria, and the sensitivity, specificity, accuracy, positive predictive value, and negative predictive value for differentiating two groups were 86.2%, 79.3%, 81.2%, 84.2%, and 85.6%, respectively.


CONCLUSIONS
Diffusion-weighted imaging is a promising new technique for differentiating axillary inflammatory lymph nodes from metastatic lymph nodes. Compared with routine magnetic resonance sequences, DWI could provide more useful physiological and functional information for diagnosis.
Department of Radiology, Tianjin Medical University General Hospital, Tianjin 300052, China. wangjunping_tj@163.com
Junping
J
Wang
Qian
Q
Liao
Yunting
Y
Zhang
Chunshui
C
Yu
Renju
R
Bai
Haoran
H
Sun
D000818:Animals; D001365:Axilla; D003937:Diagnosis, Differential; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D007249:Inflammation / Q000473:pathology; D008207:Lymphatic Metastasis / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008325:Mammary Neoplasms, Experimental / Q000473:pathology*; D012372:ROC Curve; D011817:Rabbits; D012680:Sensitivity and Specificity