The value of contrast-enhanced ultrasound in cervical cancer assessed in comparison with magnetic resonance imaging

Abstract

Introduction. Currently, magnetic resonance imaging (MRI) is the most commonly used imaging method in the assessment of the loco-regional extension in cervical cancer. Contrast-enhanced ultrasound (abbreviated CEUS) is being investigated as an alternative or complement to the MRI investigation. Objectives. To evaluate the performance of CEUS in identifying loco-regional invasion of cervical cancer compared to MRI, considered the accepted reference standard. Method. Sixty-one patients with histopathologically confirmed cervical cancer were investigated as part of the pre-treatment workup by CEUS and MRI. We calculated the accuracy and concordance of CEUS versus MRI for tumor invasion in the vagina, bladder, rectum, parametrium, and uterus. For the time-intensity curve associated parameters analyzed (TTPK, AUC, peak intensity, wash in and wash out gradient) we calculated sensitivity, specificity and threshold value of positivity, for tumor invasion at the above-mentioned sites, with graphical representation of the ROC (receiver operating characteristic) curve. Results. CEUS was highly accurate in detecting bladder (93.4%, 95% CI: 87.2- 99.6) and uterine invasion (88.5%, 95% CI: 80.5-96.5). Substantial agreement between CEUS and MRI was observed for invasion in the uterine body (k=0.77, 95% CI: 0.56-0.98) and bladder (k=0.56, 95% CI: 0.35-0.77). ROC curve analysis for loco-regional invasions showed that the wash in gradient at a cut-off value of 2.23 had a sensitivity of 76% and a specificity of 67% in predicting uterine invasion. Conclusions. Our results demonstrate high accuracy and good agreement between CEUS and MRI regarding especially uterine and bladder invasion. This imaging method could help select patients in early stages for fertility sparing surgery, and also be of use in cases in which early bladder invasion is suspected.