Characterization of Adnexal Masses Using Contrast-Enhanced Subharmonic Imaging: A Pilot Study

Clinical value of quantitative analysis of contrast-enhanced ultrasonography in the differential diagnosis of benign and malignant pelvic tumors

Background

Cervical cancer, endometrial cancer, and ovarian cancer are among the top 10 most common cancers in women, with ovarian cancer in particular being considered a "silent killer". Therefore, early detection, diagnosis, and treatment constitute important means of care for women's health. This study investigated the clinical value of the quantitative analysis of contrast-enhanced ultrasonography (CEUS) in the differential diagnosis of benign and malignant pelvic tumors.

Methods

CEUS was performed on 151 patients with pelvic masses. Subsequently, a qualitative diagnosis was completed using the image enhancement features and tumor parameters. A multiparametric analysis of CEUS images was performed, which included the following parameters: arrival time (AT), time to peak (TTP), peak intensity (PI), and ascent slope (AS). In addition, the qualitative diagnostic efficiency of CEUS was assessed in a multiparametric analysis, and the results were compared with pathological findings.

Results

The patients in the malignant group were older (P=0.001) and had larger lesion PI values (P<0.01) than those in the benign group. The PI difference (PId) and the AS difference (ASd) showed statistical differences (P<0.01) between the myometrium and lesion tissues in the same patient. Moreover, the PId and ASd showed the largest receiver operating characteristic (ROC) curve and area under the ROC curve (AUC), with sensitivities of 90.9% and 91.7% and specificities of 86.4% and 72.5%, respectively.

Conclusions

The quantitative analysis of CEUS provides a new, simpler, and more accurate method for the differential diagnosis of benign and malignant pelvic masses in clinical practice. The sensitivities and specificities of PId and ASd were higher compared to other parameters from the same patient.

O-RADS combined with contrast-enhanced ultrasound in risk stratification of adnexal masses

BACKGROUND

Ovarian-Adnexal Reporting and Data System (O-RADS) for ultrasound is a lexicon and risk stratification system that includes all risk categories and relevant management recommendation. It has high sensitivity in diagnosing malignant adnexal tumors, but the specificity is lower.

OBJECTIVE

To explore the value of O-RADS combined with contrast-enhanced ultrasound (CEUS) in risk stratification of adnexal masses.

METHODS

A retrospective study was performed on 85 patients with 100 adnexal masses that preoperatively underwent conventional ultrasound as well as CEUS examination and obtained the postoperative pathological results. The masses were classified into O-RADS2, 3, 4, and 5 by conventional ultrasound. After contrast enhancement, the classification of O-RADS was adjusted according to CEUS imaging features. The O-RADS 2 and 3 lesions with suspected malignant features like irregular blood vessels or internal inhomogeneous hyperenhancement were upgraded to O-RADS 4, and the O-RADS 4 lesions with the above features were upgraded to O-RADS 5. The O-RADS 4 lesions with suspicious benign angiographic features like a regular vessel, interior hypoenhancement or non-enhancement were downgraded to O-RADS 3; the O-RADS 5 lesions with rim ring-enhancement and interior non-enhancement were downgraded to O-RADS 3. The sensitivity, specificity, accuracy, PPV, NPV, and AUC of the two methods were compared, taking pathological results as the gold standard.

RESULTS

The sensitivity, specificity, accuracy, PPV, NPV, and AUC of O-RADS and O-RADS combined with CEUS in the diagnosis of malignant adnexal tumors were 96.6%, 66.2%, 75.0%, 53.8%, 97.9%, 0.910 and 96.6%, 91.5%, 93.0%, 82.4%, 98.5%, 0.962, respectively. The specificity, accuracy, PPV, and AUC of O-RADS combined with CEUS were considerably higher than those of O-RADS (P < 0.01). Furthermore, both methods had excellent sensitivity and NPV but there were no significant differences between them(P > 0.05).

CONCLUSION

Combination of O-RADS and CEUS can significantly improve the specificity and PPV in diagnosing malignant adnexal tumors. It seems promising in the clinical application of risk stratification of adnexal masses.

Value of Contrast-Enhanced Ultrasound Parameters in the Evaluation of Adnexal Masses with Ovarian-Adnexal Reporting and Data System Ultrasound

OBJECTIVE

The aim of this study was to determine whether incorporating qualitative parameters of contrast-enhanced ultrasound (CEUS) can increase the accuracy of adnexal lesion assessments with Ovarian-Adnexal Reporting and Data System (O-RADS) ultrasound category 4 or 5.

METHODS

Retrospective analysis of patients with adnexal masses who underwent conventional ultrasound (US) and contrast-enhanced ultrasound (CEUS) examinations between January and August of 2020. The study investigators reviewed and analyzed the morphological features of each mass before categorizing the US images independently according to the O-RADS system published by the American College of Radiology. In the CEUS analysis, the initial time and intensity of enhancement involving the wall and/or septation of the mass were compared with the uterine myometrium. Internal components of each mass were observed for signs of enhancement. The sensitivity, specificity, and Youden's index were calculated as the contrast variables and O-RADS.

RESULTS

Receiver operating characteristic curve analysis revealed that the best cutoff value was higher than O-RADS 4. When information on the extent of enhancement was applied to selectively upgrade O-RADS category 4 and selectively downgrade O-RADS category 5, the overall sensitivity increased to 90.2%, while the level of specificity (91.3%) remained the same.

CONCLUSION

Incorporating additional information from CEUS with respect to the extent of enhancement helped to improve the sensitivity of O-RADS category 4 and 5 masses without loss of specificity.

Comparison of contrast-enhanced ultrasound, IOTA simple rules and O-RADS for assessing the malignant risk of sonographically appearing solid ovarian masses

PURPOSE

To explore the diagnostic accuracy of ovarian solid tumors by 2D ultrasound and contrast-enhanced ultrasound (CEUS).

MATERIALS AND METHODS

We retrospectively evaluated the CEUS characteristics of prospectively enrolled 16 benign and 19 malignant ovarian solid tumors. We performed International Ovarian Tumor Analysis (IOTA) simple rules and Ovarian-Adnexal Reporting and Data System (O-RADS) for all lesions, and evaluated their characteristics on CEUS. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of IOTA simple rules, O-RADS and CEUS in the diagnosis of ovarian solid malignancies were calculated.

RESULTS

The combination of time to wash-in earlier than or equal to the myometrium, time to PI earlier than or equal to the myometrium and the intensity at peak were higher than or equal to myometrium with sensibility of 0.947, specificity of 0.938, and PPV of 0.947, NPV of 0.938 which were higher than IOTA simple rules and O-RADS. According to the definition of ovarian solid tumor, the diagnostic accuracy of O-RADS 3 and CEUS were both 100%, CEUS improved the accuracy of O-RADS 4 from 47.4% to 87.5%, the accuracy of solid smooth CS 4 in O-RADS 5 and CEUS were both 100%, CEUS improved the accuracy of solid irregular in O-RADS 5 from 70% to 87.5%.

CONCLUSION

For ovarian solid tumors that are difficult to distinguish between benign and malignant, the introduction of CEUS on the basis of 2D classification criteria can significantly improve the diagnostic accuracy.

Contrast-enhanced ultrasonography for differential diagnosis of adnexal masses

Background

Quantitative contrast-enhanced ultrasonography parameters are affected by various factors. We evaluated corrected quantitative contrast enhanced ultrasonography in differentiating benign adnexal tumors from malignant tumors.

Methods

Patients with adnexal masses who underwent conventional and contrast-enhanced ultrasonography were included. Contrast-enhanced ultrasonography parameters such as base intensity, arrival time, peak intensity, time to peak intensity, ascending slope, and descending slope were measured. Corrected (time to peak intensity − arrival time) _mass/(time to peak intensity − arrival time) _uterus and (peak intensity − base intensity) _mass/(peak intensity − base intensity) _uterus were calculated. Lesions were confirmed by pathologic examination of surgical specimens.

Results

This study included 31 patients with 35 adnexal lesions including 20 (57.10%) benign and 15 (42.90%) malignant lesions. The corrected contrast-enhanced ultrasonography quantitative parameters in lesions were statistically different between malignant and benign groups (P<0.05). The optimal cut-off value for (time to peak intensity − arrival time) _mass/(time to peak intensity − arrival time) _uterus, ascending slope, and (peak intensity − base intensity) _mass/(peak intensity − base intensity) _uterus, and descending slope for differentiating malignant adnexal masses from benign tumors were 1.05 (area under curve: 0.93, P<0.05), 1.11 (area under curve: 0.83, P<0.05), 0.82 (area under curve: 0.73, P<0.05), and −0.27 (area under curve: 0.66, P=0.16), with sensitivity and specificity of 93.33% and 85.00%, 86.67% and 75.00%, 86.67% and 60.00%, and 54.55% and 66.67%, respectively.

Conclusions

Corrected contrast-enhanced ultrasonography parameters provide practical differential diagnosis value of adnexal lesions with high reliability for sonologists.

On the threshold of 1/2 order subharmonic emissions in the oscillations of ultrasonically excited bubbles

The pressure threshold for 1/2 order subharmonic (SH) emissions and period doubling during the oscillations of ultrasonically excited bubbles is thought to be minimum when the bubble is sonicated with twice its resonance frequency (f_r). This estimate is based on studies that simplified or neglected the effects of thermal damping. In this work, the nonlinear dynamics of ultrasonically excited bubbles is investigated accounting for the thermal dissipation. Results are visualized using bifurcation diagrams as a function of pressure. Here we show that, and depending on the gas, the pressure threshold for 1/2 order SHs can be minimum at a frequency between 0.5f_r≤f≤0.6f_r. In this frequency range, the generation of 1/2 order SHs are due to the occurrence of 5/2 order ultra-harmonic resonance. The stability of such oscillations is size dependent. For an air bubble immersed in water, only bubbles bigger than 1 μm in diameter are able to emit non-destructive SHs in these frequency ranges.

Contrast-Enhanced Subharmonic Aided Pressure Estimation (SHAPE) using Ultrasound Imaging with a Focus on Identifying Portal Hypertension

Noninvasive, accurate measurement of pressures within the human body has long been an important but elusive clinical goal. Contrast agents for ultrasound imaging are gas-filled, encapsulated microbubbles (diameter < 10 μm) that traverse the entire vasculature and enhance signals by up to 30 dB. These microbubbles also produce nonlinear oscillations at frequencies ranging from the subharmonic (half of the transmit frequency) to higher harmonics. The subharmonic amplitude has an inverse linear relationship with the ambient hydrostatic pressure. Here an ultrasound system capable of performing real-time, subharmonic aided pressure estimation (SHAPE) is presented. During ultrasound contrast agent infusion, an algorithm for optimizing acoustic outputs is activated. Following this calibration, subharmonic microbubble signals (i.e., SHAPE) have the highest sensitivity to pressure changes and can be used to noninvasively quantify pressure. The utility of the SHAPE procedure for identifying portal hypertension in the liver is the emphasis here, but the technique has applicability across many clinical scenarios.