Mohamed Abou El-Ghar MSc, MD, Presenter: Nothing to Disclose

Ahmed Adel Mansour BMedSc, Abstract Co-Author: Nothing to Disclose

Huda Refaie MD, Abstract Co-Author: Nothing to Disclose

Tarek A. El-Diasty MBBCh, MD, Abstract Co-Author: Nothing to Disclose

To assess the utility of Diffusion weighted MRI (DWI) including apparent diffusion coefficient (ADC) for distinguishing lymph nodes harboring metastatic disease in bladder cancer patients.

The study cohort included 138 patients who underwent MRI with diffusion weighted imaging prior to radical cystectomy between April 2012 and May 2013. ADC values were measured in a circular region of interest where lymph node enlargement was found. Two radiologists blinded to the pathologic outcome interpreted the DW images. All patients underwent radical cystectomy with bilateral extended lymphadenectomy extending above the bifurcation of the common iliac vessels. Anatomical mapping of the removed lymph nodes was performed intraoperatively and the nodes were sent in separate packages for pathological assessment. Qualitative analysis of lymph nodes ans the ADC values obtained from the enlarged lymph nodes  were then correlated with the final pathological assessment of the resected lymph nodes.  

One hundred and thirty eight patients were evaluated by DW-MRI. Patients with radiological lymph node enlargement were identified (n=88, 63%), ADC values were calculated in areas of lymph node enlargement in four anatomical regions on each side, namely, common iliac, external iliac, internal iliac and obturator regions. Mean(SD) ADC value was 1.06 (0.2) x10-3 mm2/s. There was a significant difference in ADC values of areas of metastatic lymph nodes and areas of negative node involvement (p=0.0012). ROC analysis identified an optimal ADC threshold of 1.25 x10-3 mm2/s for identifying the presence or absence of metastatic disease. Qualitative analysis shows no difference between metaststic and non-metastatic lymph nodes.  

Our results suggests that DW-MRI ADC values correlate with the presence of metastatic disease in patients with bladder cancer and radiologically enlarged lymph nodes. Qualitative analysis shows fluid restriction in both metastatic and non metastatic nodes.  

ADC values can differentiate enlarged  lymph nodes with tumor metastases from that without metastases in cases of bladder cancer.

El-Ghar, M, Mansour, A, Refaie, H, El-Diasty, T, Characterization of Lymph Node Metastases Using Diffusion-weighted MRI in Cases of Bladder Cancer.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14001386.html