ABSTRACT
<p><b>OBJECTIVE</b>To compare the diagnostic value of gadolinium diethylenetriaminepenta-acetic acid (Gd-DTPA)-enhanced MRI with ultrasmall superparamagnetic iron oxide (USPIO)-enhanced MRI in differentiating reactive hyperplastic lymph nodes from metastatic lymph nodes in rabbit models.</p><p><b>METHODS</b>Reactive hyperplastic cervical lymph node model was established in 18 rabbits as hyperplasia group, and tumor-bearing lymph node model was established in another 18 rabbits as tumor group. For Gd-DTPA-enhanced MRI, T1WI and T2WI were performed on 9 animals of each model, and T1WI was acquired 80 seconds after administration of Gd-DTPA. For USPIO-enhanced MRI, T1WI, T2WI and T2*WI were performed on another 9 animals of each model before and 24 hours after administration of USPIO. MRI images were analyzed and correlated with surgical specimens and pathological results.</p><p><b>RESULTS</b>In the tumor group, the sensitivity, specificity, positive predictive value, negative predictive value and accuracy of Gd-DTPA-enhanced MRI were 62.5%, 91.3%, 88.2%, 70.0% and 76.6%, respectively. The corresponding values of USPIO-enhanced MRI were 95.0%, 90.9%, 90.5%, 95.2% and 92.9%, respectively. The sensitivity and accuracy of USPIO-enhanced MRI differ significantly from those of Gd-DTPA-enhanced MRI. In the hyperplasia group, the accuracy of Gd-DTPA-enhanced MRI was 74.2%, while 87.1% for USPIO-enhanced MRI.</p><p><b>CONCLUSION</b>USPIO-enhanced MRI has higher accuracy in diagnosing metastatic lymph nodes than Gd-DTPA-enhanced MRI.</p>