MRI and 11C Acetate PET/CT for prediction of regional lymph node metastasis in newly diagnosed prostate cancer.

Abstract

Objective: To examine the value of quantitative and qualitative MRI and ¹¹C Acetate PET/CT parameters,, in predicting regional lymph node (LN) metastasis in newly diagnosed prostate cancer (PCa).

Methods: Patients with intermediate (n=6) and high risk (n=47) PCa underwent 3T MRI (40 patients) and ¹¹C Acetate PET/CT (53 patients) before extended pelvic LN dissection.  For each patient the visually most suspicious LN was assessed for ADCmean, SUVmax, size and shape and the primary tumour for T stage on MRI and ADCmean and SUVmax in the index lesion. The variables were analysed in simple and multiple logistic regression analysis.

Results: All variables, except ADCmean and SUVmax of the primary tumor, were independent predictors of LN metastasis. In multiple logistic regression analysis the best model was ADCmean in combination with MRI T-stage where both were independent predictors of LN metastasis, this combination had an AUC of 0.81 which was higher than the AUC of 0.65 for LN ADCmean alone and the AUC of 0.69 for MRI T-stage alone.

Conclusion: Several quantitative and qualitative imaging parameters are predictive of regional LN metastasis in PCa. By combining lymph node ADCmean and MRI T-stage the predictive value was increased compared to that of each parameter alone.