Huadan Xue MD, Presenter: Nothing to Disclose

Li Shuo MD, Abstract Co-Author: Nothing to Disclose

Jin Zheng Yu, Abstract Co-Author: Nothing to Disclose

To investigate the feasibility of MR diffusion-weighted imaging (DWI) on normal, inflammatory and VX2 carcinoma metastatic lymph nodes in rabbit model and its potential use for discrimination.

20 New-Zealand White rabbits were divided randomly into 2 groups. Complete Freund adjuvant was injected into the left dorsal footpads to set up ipsilateral lymphadenitis model (n=10), while the right extremities were measured as normal control. The other 10 rabbits received a subcutaneous implantation of VX2 tumor cell suspension in their right thighs in order to set a metastatic LN model. MRI scan covered bilateral popliteal fossa including STIR-EPI-DWI, T1WI and T2WI series were performed 2hrs prior to as well as 2 weeks after injection. Apparent diffusion coefficient values of the lymph nodes were evaluated in all cases. Pathological result were collected after lymph nodes resection(right after the 2nd MRI scan) and hematoxylin-eosin staining for verification.

Normal(n=10), inflammatory (n=10) and VX2 carcinoma metastatic lymph nodes (n=14) DWI image without fat contamination or significant distortion were found in the popliteal fossa verified by the corresponding pathological results. The size of inflammatory lymph nodes (8.11±0.60mm) was almost the same as VX2 carcinoma metastatic groups (9.17±0.60mm), while they were much larger than normal group (4.74±0.43mm)(T-test, p<0.01). All lymph nodes appeared isointense on T1WI and hyperintense on T2WI. The mean ADC value of inflammatory nodes (1.14±0.02×10-3mm2/s) was significantly higher (T-test, P<0.01) than that of metastatic nodes (0.78±0.07×10-3mm2/s), and normal nodes showed even higher levels of ADC value (1.35±0.15×10-3mm2/s) than the former two groups (T-test, P<0.01).

STIR-EPI-DWI is a new promising technique for differentiating normal, inflammatory and metastatic lymph nodes. The addition of DWI to routine MR sequence may provides more useful physiological and functional information for tumor diagnosis.

DWI can demonstrate lymph node property in animal models, and can be possibly put in clinical use of lymph node metastasis differentiation in human.

Xue, H, Shuo, L, Zheng Yu, J, The Experimental Study of Normal, Inflammatory and Metastatic Lymph Nodes with MR Diffusion-weighted Imaging on Animal Model.  Radiological Society of North America 2007 Scientific Assembly and Annual Meeting, November 25 - November 30, 2007 ,Chicago IL. http://archive.rsna.org/2007/5004111.html