Evaluation of lymph node metastases in gastric cancer using magnetic resonance imaging with ultrasmall superparamagnetic iron oxide (USPIO): diagnostic performance in post-contrast images using new diagnostic criteria
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- Tokuhara, T., Tanigawa, N., Matsuki, M. et al. Gastric Cancer (2008) 11: 194. doi:10.1007/s10120-008-0480-9
We assessed the value of magnetic resonance imaging (MRI), using ultrasmall superparamagnetic iron oxide (USPIO) with new diagnostic criteria, in the evaluation of regional lymph node metastases in gastric cancer.
Thirty-one patients with gastric cancer were enrolled. 1000 lymph nodes were dissected during surgery, and of these, 519 nodes (51.9 %) were identified by currently used MRI imaging analysis. We evaluated lymph nodes on USPIO-post-contrast T2*-weighted images using the following two criteria: (1) we diagnosed the nodes on T2*-weighted images according to conventional criteria, where a node having an overall low signal intensity (pattern A) was nonmetastatic, while a node having partial (pattern B) or overall (pattern C) high signal intensity was metastatic; (2) we subdivided pattern B nodes on T1-weighted images using the new criteria, in which a node for which the high-intensity area on T2*-weighted images was not defined as adipose tissue on T1-weighted images (pattern B1) was metastatic, while a node for which the high-intensity area was defined as adipose tissue (pattern B2) was nonmetastatic.
(1) The results using the conventional criteria were 96.2% sensitivity, 92.5% specificity, 76.3% positive predictive value (PPV), 99.0% negative predictive value (NPV), and 93.3% accuracy. (2) The results using the new criteria were 96.2% sensitivity, 98.3% specificity, 90.1% PPV, 99.0% NPV, and 97.1% accuracy.
The assessment of lymph node metastases from USPIO-post-contrast MRI alone using the new criteria was useful in the diagnosis of regional lymph node metastases in gastric cancer.