Minimum apparent diffusion coefficient for predicting lymphovascular invasion in invasive cervical cancer

Abstract

Purpose: To investigate the diagnostic performance of minimum apparent diffusion coefficient (mini-ADC) for predicting lymphovascular invasion (LVI) in invasive cervical cancer. Materials and Methods: Ninety-six patients with pathologically confirmed invasive cervical cancer (CC) underwent conventional preoperative magnetic resonance imaging (MRI) and diffusion-weighted imaging (DWI) on a 3.0T MRI system. Tumor ADC, mini-ADC and mini-ADC ratio (mini-ADC value / tumor ADC value) were obtained and compared between LVI-positive and LVI-negative invasive CC, and correlation between LVI status and Ki-67, p16, p63, and clinical prognostic factors were analyzed. ADC thresholds and diagnostic performance were determined by receiver operating characteristic (ROC) analysis. Results: Tumor ADC showed no significant difference (P = 0.300) between LVI-positive invasive CC (n = 27) and LVI-negative invasive CC (n = 69); the mini-ADC and mini-ADC ratio were significantly lower in LVI-positive invasive CC than in LVI-negative invasive CC ([0.712 ± 0.078 × 10−3 mm2/s] vs. [0.867 ± 0.099 × 10−3 mm2/s], P < 0.001; and [0.772 ± 0.062] vs. [0.917 ± 0.052], P < 0.001, respectively). ROC curve analysis yielded a cutoff mini-ADC value of 0.837 in the differentiation of LVI-positive and LVI-negative invasive CC, with a sensitivity of 65%, specificity of 100%, and area under the curve (AUC) of 0.885; a cutoff mini-ADC ratio of 0.875 with a sensitivity of 78%, specificity of 100%, AUC of 0.970, positive predictive value of 100%, and negative predictive value of 64%. There was a positive correlation between LVI status and Ki-67 (r = 0.241, P = 0.014) and a negative correlation between mini-ADC and LVI status (r = –0.582, P < 0.001); mini-ADC and Ki-67 (r = –0.587, P < 0.001). Conclusion: Mini-ADC value appears to be a simple and effective tool for the prediction of LVI status in invasive CC, and the mini-ADC ratio may be the best parameter in discriminating between LVI-positive and LVI-negative invasive CC. Level of Evidence: 1. Technical Efficacy: Stage 4. J. MAGN. RESON. IMAGING 2017;45:1771–1779.