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.

Methods: 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.

Keywords: cervical cancer; contrast-enhanced ultrasonography; magnetic resonance imaging.

Figure 1

CEUS. Graphical representation of TIC in the arterial phase in a 70-year-old ME patient diagnosed with stage IIIB squamous carcinoma of the cervix. Yellow is the TIC curve in the tumor area of maximum intensity. Green shows the TIC curve in apparently tumour-free tissue.

Figure 2

A. CEUS in patient KS, 76 years old, stage IVA cervical cancer. Sagittal grayscale image (left) and CEUS image 3 minutes after SonoVue injection. Loss of bladder-cervical and cervico-uterine space contour with tumor infiltration of the entire bladder wall is seen. B. Sagittal MRI image in T2 sequence - tumour invasion into the vesico-uterine space with loss of bladder wall contour is observed. C. Axial T2-slice MRI image showing full bladder wall invasion.

Figure 3

ROC curve of CEUS parameters for uterine invasion (IP - intensity peak, TTPK - time to peak, AUC - area under the curve, Gradient - wash in gradient, wash out gradient).