Added Value of Contrast-enhanced US for Evaluation of Female Pelvic Disease

Since the first application of contrast-enhanced US (CEUS) in the late 1960s, the use of US contrast agents has grown tremendously, and this examination has proved to be a valuable adjunct to diagnostic US for detection and characterization of disease. Also, CEUS has emerged as an excellent option for evaluation of indeterminate lesions that require additional imaging, given its excellent safety profile, including that in patients with end-stage renal disease or allergies to contrast material who are unable to undergo contrast-enhanced CT or MRI. US traditionally has been considered the imaging modality of choice for evaluation of the female pelvis, followed by MRI and rarely fluoroscopy, CT, PET, or angiography. CEUS has the potential to add significant value in imaging gynecologic disease, and indications for its use in the female pelvis are expected to continue evolving. It can aid in evaluation of nonvascular structures, such as assessment of tubal patency, uterine cavity morphology, and pelvic fistulas. CEUS can help characterize poorly vascularized gynecologic tumors or tissues with slow flow by using qualitative and quantitative parameters and aid in image-guided interventions or biopsies by facilitating visualization of lesions that are difficult to see with other imaging modalities. The authors provide an overview of current applications of US contrast agents in the female pelvis and discuss associated factors such as technique, interpretation, and image optimization. They also discuss the limitations of CEUS and describe its utility in the evaluation of female pelvic disease by using an organ system case-based approach. © RSNA, 2024 Test Your Knowledge questions for this article are available in the supplemental material.

Contrast-Enhanced Ultrasound Imaging of Uterine Disorders: A Systematic Review

Uterine disorders are often presented with overlapping symptoms. The microvasculature holds specific information important for diagnosing uterine disorders. Conventional sonography is an established diagnostic technique in gynecology, but is limited by its inability to image the microvasculature. Contrast-enhanced ultrasound (CEUS), is capable of imaging the microvasculature by means of intravascular contrast agents; that is, gas-filled microbubbles. We provide a literature overview on the use of CEUS in diagnosing myometrial and endometrial disorders, that is, fibroids, adenomyosis, leiomyosarcomas and endometrial carcinomas, as well as for monitoring and enhancing the effectiveness of minimally invasive therapies. A systematic literature search with quality assessment was performed until December 2020. In total 34 studies were included, published between 2007 and 2020.The results entail a description of contrast-enhancement patterns obtained from healthy tissue and from malignant and benign tissue; providing a first base for potential diagnostic differentiation in gynecology. In addition it is also possible to determine the degree of myometrial invasion in case of endometrial carcinoma using CEUS. The effectiveness of minimally invasive therapies for uterine disorders can safely and accurately be assessed with CEUS. In conclusion, the abovementioned applications of CEUS are promising and it is worth further exploring its full potential for gynecology by designing innovative and methodologically high-quality clinical studies.

Diagnostic Value of Quantitative Analysis by Contrast-Enhanced Ultrasound of Endometrial Lesions

OBJECTIVES

To explore the diagnostic value of time-intensity curve parameters from contrast-enhanced ultrasound (CEUS) examinations of endometrial lesions.

METHODS

Fifty-two patients with suspected endometrial lesions who received vaginal CEUS examinations were divided into a polyp group (n = 36), a malignant group (n = 11), and a normal control group (n = 5) based on the pathologic diagnosis. The midpoint of the myometrium at the same depth as the endometrial lesion was used as the reference point. The initial increase time, time to peak, area under the curve, and peak intensity were determined by the time-intensity curve. The relative parameters, namely, the initial increase time difference, peak time difference, area ratio, and peak intensity ratio, were also calculated and analyzed statistically.

RESULTS

The comparison results of the relative parameters among the groups showed that the differences in the time difference, intensity ratio, and area ratio were statistically significant. The differences in the intensity ratio and time difference between the malignant and normal groups were statistically significant (P < .001). The differences in the intensity ratio, area ratio, and time difference between the malignant and polyp groups were statistically significant (P < .001). The diagnostic value of the intensity ratio and area ratio was confirmed by a receiver operating characteristic curve. The sensitivity and specificity of the intensity ratio and area ratio in the groups were 100% and 77.5% and 85.7% and 85.0%, respectively.

CONCLUSIONS

The relative CEUS parameters in endometrial lesions provide more diagnostic value in differential diagnosis of benign and malignant lesions than the absolute parameters.

Value of preoperative staging of endometrial carcinoma with contrast-enhanced ultrasonography: A PRISMA compliant meta-analysis

INTRODUCTION

Endometrial carcinoma (EC) is the most common gynecologic carcinoma in developed countries and accounts for nearly 5% of carcinoma cases and more than 2% of deaths due to female carcinomas worldwide. Because of this reported risk, it is very important to diagnose and stage it accurately. Therefore, we investigated the staging accuracy of EC with contrast-enhanced ultrasonography (CEUS). Due to a lack of studies on the use of CEUS in staging EC, we performed a systematic review and meta-analysis.

METHOD

We searched PubMed, EMBASE, Cochrane Library, Scopus, Web of science, China National Knowledge Infrastructure (CNKI), and CBM for studies on CEUS in EC diagnosis. Our search keywords were "ultrasonic angiography," "endometrial neoplasms," and their synonyms. The studies were screened according to the inclusion and exclusion criteria, and 4 tabular data were extracted. Quality evaluation was performed with the Quality Assessment of Diagnostic Accuracy Studies (QUADAS) scale. Statistical analysis was done with Stata version 15.1. A random effect model was selected to calculate the pooled sensitivity and specificity. The summary receiver operating characteristic (SROC) curve was obtained, and the area under the curve was calculated.

RESULT

Fifteen studies with 685 patients were included in this quantitative synthesis. The pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio (OR) of CEUS in the diagnosis of EC was 0.81 (95% confidence interval, .76-.85), .90 (.87-.92), 8 (5.8-11.1), .21 (.16-.28), and 38 (22-67), respectively. The area under the curve was 0.93 (.90-.95).

CONCLUSION

CEUS has a high sensitivity and specificity in the diagnosis of EC. It can be considered as an effective and feasible method for EC staging.

Dynamic contrast-enhanced ultrasound improves diagnostic performance in endometrial cancer staging

OBJECTIVES

To compare the sensitivity and specificity of conventional two-dimensional transvaginal ultrasound/power Doppler (2D-TVU/PD) alone and 2D-TVU/PD combined with dynamic contrast-enhanced ultrasound (DCE-US) in diagnosing deep myometrial invasion (MI) and cervical stromal involvement (CSI) in women with endometrial cancer (EC), and to assess the association of DCE-US semiquantitative and qualitative variables with International Federation of Gynecology and Obstetrics (FIGO) Stage ≥ IB and 'high-risk' cancer.

METHODS

This was a prospective study of 101 consecutive women with biopsy-confirmed EC, undergoing expert ultrasound examination at Karolinska University Hospital, a tertiary referral center. All consenting women underwent DCE-US using a 1.5-2.5-mL intravenous bolus of SonoVue contrast agent, as well as conventional 2D-TVU/PD examination. DCE-US videoclips were analyzed with regard to filling (global or focal), wash-in (prior, simultaneous or after) and wash-out (global or focal) patterns of the contrast agent in the tumor compared with the surrounding tissue, as well as semiquantitative DCE-US parameters (wash-in slope, time-to-peak, peak intensity and area under the time-intensity curve (TIC)) obtained from a TIC. The study cohort was compared with a control cohort of women with EC examined at our center according to the International Endometrial Tumor Analysis protocol using 2D-TVU/PD only, matched at a ratio of 3:1 for FIGO stage and grade. The sensitivity and specificity of 2D-TVU/PD alone in the control cohort and in combination with DCE-US in the study cohort in the diagnosis of deep MI, CSI and high-risk cancer (defined as FIGO Stage ≥ IB and/or Grade 3 endometrioid and/or non-endometrioid histology) were compared, using pathological evaluation after hysterectomy as the 'gold standard'.

RESULTS

After exclusions, 93 women were included in the study cohort and were matched to 279 women in the control cohort. The prevalence of FIGO Stage IA, Grade 1-2 EC was 52% in both cohorts. The sensitivity of 2D-TVU/PD with DCE-US in the study cohort was higher than that of 2D-TVU/PD alone in the control cohort in diagnosing both deep MI (0.74 vs 0.62; P = 0.036) and CSI (0.75 vs 0.51; P < 0.001), whereas the specificity was not significantly different (0.87 vs 0.85 and 0.96 vs 0.95, respectively). Compared with 2D-TVU/PD alone, the specificity of 2D-TVU/PD with DCE-US was higher in detecting high-risk cancer (0.94 vs 0.85; P = 0.024) but the sensitivity did not differ (0.73 vs 0.71). High-risk cancer and FIGO Stage ≥ IB were characterized by a 'focal' filling pattern, with a 'prior' wash-in pattern and a 'focal' wash-out pattern on subjective assessment of DCE-US videoclips. All semiquantitative DCE-US parameters were significantly predictive of FIGO Stage ≥ IB but not of high-risk cancer, despite a clear trend.

CONCLUSIONS

Compared with 2D-TVU/PD alone, combining 2D-TVU/PD with DCE-US can significantly improve the detection of deep MI and CSI in women with EC, without increasing the false-positive rate. It can also improve the correct classification of high-risk disease, mainly by increasing specificity, thereby possibly reducing the number of unnecessarily extensive surgeries by almost 10%. Semiquantitative DCE-US parameters, as well as a 'focal' filling pattern, endometrial wash-in prior to the myometrium and a 'focal' wash-out pattern, are all associated with more advanced disease. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Application of contrast-enhanced ultrasound for scar pregnancy cases misdiagnosed as other diseases

OBJECTIVE

To demonstrate the feasibility of utilizing contrast-enhanced ultrasound (CEUS) in scar pregnancies misdiagnosed by transvaginal ultrasound (TVS).

METHODS

CEUS was performed in three patients with clinically suspected abnormal pregnancy, and the diagnosis were inconclusive by TVS. Clinical manifestations and features of TVS and CEUS in these cases were analyzed.

RESULTS

Three cases included an intramural pregnancy (IMP) after hysteromyomectomy, and two mass-based cesarean scar pregnancy (CSP), the mass was caused by curettage and spontaneous abortion, respectively. In all these cases, early enhancement with high intensity was observed by CEUS at the site of implantation. Moreover, prominently enhanced signal was detected inside the mass, with or without peritrophoblastic ring. No enhancement was detected in clots or masses after effective treatment.

CONCLUSION

CEUS can be used as a supplementary method to diagnose scar pregnancy and evaluate the treatment efficacy, especially in cases with ambiguous results by TVS.

Prognostic Value of Quantitative Perfusion Parameters by Enhanced Ultrasound in Endometrial Cancer

Background

Tumor perfusion is significantly associated with the development and aggressiveness of endometrial cancer. The aim of this study was to assess the prognostic value of quantitative perfusion parameters measured by contrast-enhanced ultrasonography (CEUS) in endometrial cancer before surgery.

Material/Methods

A total of 223 patients with endometrial cancer were included between 1 May 1 2013 and 1 May 1 2017 for preoperative CEUS. The mean enhancement rate (ER) was calculated as enhancement intensity (EI)/rise time (RT) results from time-intensity curve (TIC) during CEUS. After a mean follow-up of 33.5±9.9 months, the correlation of ER and postoperative overall survival (OS) and disease-free survival (DFS) was analyzed using univariate and multivariate analysis.

Results

The optimal cutoff ER value predicting survival based on the ROC curve was 1.8 dB/s. Kaplan-Meier univariate analysis demonstrated that a patient with a high ER level had worse DFS and OS than those with a low ER (DFS, P<0.01; OS, P<0.05). In multivariate analysis, ER was confirmed as an independent predictor for both recurrence (HR, 1.68; 95% CI: 1.01–7.73) and OS (HR, 1.98; 95%CI: 1.01–7.83) for patients with endometrial cancer (both P<0.05).

Conclusions

Perfusion variables measured by CEUS are significantly useful predictive factor for postoperative survival in endometrial cancer.

Contrast-enhanced ultrasound in the diagnosis of endometrial carcinoma: A meta-analysis

The present study evaluated the diagnostic value of contrast-enhanced ultrasound (CEUS) in endometrial carcinoma (EC). Articles published until 31 January 2017 were retrieved from PubMed, EMBASE, Elsevier, Springer and Google scholar, with the following inclusion criteria: i) The accuracy (sensitivity and specificity) of CEUS in the diagnosis of EC was evaluated; ii) a gold standard was adopted to treat and confirm EC, including surgery, histopathology and appropriate follow-up (as included in the meta-analysis); iii) the data allowed for construction of a 2×2 table of positives, false-positives, negatives and false-negatives. Pooled estimates of sensitivity, specificity, risk ratios and diagnostic odds ratios (DOR) were calculated in the present meta-analysis of the accuracy of CEUS in diagnosing EC. The summary receiver-operating characteristics (sROC) curve was also constructed. Among the 93 relevant articles, 7 studies were finally selected according to the inclusion criteria with a sample size of n=275. The pooled sensitivity of CEUS in the diagnosis of EC was 84% [95% confidence interval (CI), 0.78-0.88], while the pooled specificity was 90% (95% CI, 0.86-0.92). The positive likelihood ratio (+LR) of CEUS was 8.0 (95% CI, 5.9-10.8) and the negative likelihood ratio (-LR) was 0.18 (95% CI, 0.13-0.25). The DOR was 44 (95% CI, 26-77). The area under the sROC curve was 0.93 with specificity of 0.90 (0.86-0.92) and sensitivity of 0.84 (0.78-0.88) for the summary operating point. Moderate heterogeneity was observed for sensitivity, specificity and DOR with I² values of 32.56, 34.68 and 41.2%, respectively. No significant publication bias was observed for the DOR of CEUS. In conclusion, the present meta-analysis indicates that CEUS is valuable in the diagnosis of EC. Additional clinical data and studies are still required to confirm these results and to further develop the diagnostic application of CEUS in EC.

Use of Contrast-Enhanced Ultrasound in the Assessment of Uterine Fibroids: A Feasibility Study

Contrast-enhanced ultrasound (CEUS) is an innovative ultrasound technique capable of visualizing both the macro- and microvasculature of tissues. In this prospective pilot study, we evaluated the feasibility of using CEUS to visualize the microvasculature of uterine fibroids and compared CEUS with conventional ultrasound. Four women with fibroids underwent gray-scale ultrasound, sonoelastography and power/color Doppler scans followed by CEUS examination. Analysis of CEUS images revealed initial perfusion of the peripheral rim, that is, a pseudo-capsule, followed by enhancement of the entire lesion through vessels traveling from the exterior to the interior of the fibroid. The pseudo-capsules exhibited slight hyper-enhancement, making a clear delineation of the fibroids possible. The centers of three fibroids exhibited areas lacking vascularization, information not obtainable with the other imaging techniques. CEUS is a feasible technique for imaging and quantifying the microvasculature of fibroids. In comparison with conventional ultrasound imaging modalities, CEUS can provide additional diagnostic information based on the microvasculature.

The diagnostic value of endoscopic ultrasonography and contrast-enhanced harmonic endoscopic ultrasonography in gastrointestinal stromal tumors

Objective:

To evaluate the diagnostic value of endoscopic ultrasonography (EUS) and contrast-enhanced harmonic (CEH) EUS in patients with gastrointestinal stromal tumors (GISTs).

Patients and Methods:

About 19 patients with suspected GISTs underwent EUS and CEH-EUS before tumor resection. The malignant potential was assessed according to the modified Fletcher classification system. Patients were divided into lower (Group I) and higher (Group II) malignant potential group. The clinical characteristics and EUS/CEH-EUS features were compared between two groups.

Results:

The tumor size in Group II was significantly larger than that in Group I (14.6 ± 5.8 mm vs. 32.1 ± 8.4 mm, P < 0.05). Heterogeneous echogenicity was observed in 4 (4/8) cases in Group II and none in Group I (P < 0.05). Irregular intratumoral vessels were detected in 6 cases in Group II and none in Group I (P < 0.05). The sensitivity and specificity of irregular vessel detection for discriminating higher from lower malignant potential GISTs were 75% and 100%, respectively. The positive predictive value and negative predictive value of detection of irregular vessels to high malignant potential GISTs were 33% and 100%, respectively.

Conclusion:

Detection of irregular intratumoral vessels can predict higher malignant potential before tumor resection. The tumor size and echogenicity are assistant factors for malignant potential assessment. Endoscopic resection is an efficacious treatment with good security for appropriate patients.

Comparison of Uterine Receptivity between Fertile and Unexplained Infertile Women by Assessment of Endometrial and Subendometrial Perfusion Using Contrast-Enhanced Ultrasound: Which Index is Better--Peak Intensity or Area under the Curve?

The goal of this study was to compare uterine receptivity between women with normal fertility and those with unexplained infertility during natural cycles by assessment of endometrial and subendometrial perfusion using contrast-enhanced ultrasound (CEUS). We wanted to determine the better index: peak intensity (PI) or area under the curve (AUC). Thirty women with unexplained infertility were recruited into the study group, and 30 women with normal fertility were recruited into the control group. All women underwent CEUS during the late proliferative phase, ovulation phase, and implantation window of a menstrual cycle. Endometrial PI, endometrial AUC, subendometrial PI and subendometrial AUC were analyzed. In the late proliferative phase, the control group had a significantly higher endometrial PI (p < 0.001) as well as subendometrial PI (p < 0.001) and AUC (p = 0.004) than the study group. In the ovulation phase, the control group had a significantly higher endometrial PI (p < 0.001) and AUC (p = 0.021), as well as subendometrial PI (p < 0.001) and AUC (p = 0.003). During the implantation window, there were no significant differences between the two groups. Only subendometrial PI underwent a significant periodic change during the menstrual cycle in both groups. This finding was further confirmed by evaluation of the microvessel density of endometria. In conclusion, CEUS can be used to assess endometrial and subendometrial perfusion to evaluate uterine receptivity. Subendometrial PI was the most sensitive index compared with endometrial PI, endometrial AUC and subendometrial AUC.

Role of contrast-enhanced ultrasound (CEUS) in the diagnosis of endometrial pathology

Ultrasound is the reference imaging procedure used for the exploration of endometrial pathology. As medical procedures improve and the requirements of modern medicine become more demanding, gray-scale ultrasound is insufficient in establishing gynecological diagnosis. Thus, more complex examination techniques are required: Doppler ultrasound, contrast-enhanced ultrasound (CEUS), 3D ultrasound, etc. Contrast-enhanced ultrasound is a special examination technique that gains more and more ground. This allows a detailed real-time evaluation of microcirculation in a certain territory, which is impossible to perform by Doppler ultrasound. The aim of this review is to synthesize current knowledge regarding CEUS applications in endometrial pathology, to detail the technical aspects of endometrial CEUS and the physical properties of the equipment and contrast agents used, as well as to identify the limitations of the method.

Imaging of endometrial carcinoma using contrast-enhanced sonography

OBJECTIVES

The purpose of this study was to evaluate the utility of contrast-enhanced sonography as an adjunct to conventional transvaginal sonography for detecting endometrial carcinoma and defining the depth of myometrial invasion.

METHODS

A total of 35 patients with endometrial carcinoma diagnosed by endometrial sampling were examined with transvaginal sonography followed by contrast-enhanced sonography before treatment. The contrast enhancement phases (ie, early wash-in/out and late wash-in/out) were visually observed before comparison of tumors grouped by average diameter and histopathologic grade. We evaluated the effectiveness of contrast-enhanced sonography as an adjunct to transvaginal sonography in tumor imaging. We calculated the accuracy of contrast-enhanced sonography for diagnosing the depth of tumor invasion into the myometrium by using arcuate vascular plexus involvement as the sonographic standard for diagnosis of deep myometrial infiltration.

RESULTS

Of the 34 tumors identified by contrast-enhanced sonography, 28 (82.4%) showed early wash-in, and 6 (17.6%) showed late wash-in. Similar numbers of cases showed early and late wash-out. The enhancement phases did not differ significantly across groups with different average tumor diameters or histologic grades (P > .05). Contrast-enhanced sonography contributed the most to tumor imaging in patients with a thin endometrium after endometrial biopsy because it enhanced the contrast between the tumor and tissue. The diagnostic accuracy of contrast-enhanced sonography for determining the myometrium infiltration depth was 85.3%.

CONCLUSIONS

This study revealed diagnostically useful characteristics of the enhancement phase of endometrial carcinoma. The ability to enhance tumor-to-tissue contrast makes contrast-enhanced sonography a valuable adjunct to conventional sonography of endometrial carcinoma, especially for the thin endometrium found after endometrial biopsy. Contrast-enhanced sonography performed well in the diagnosis of the myometrial infiltration depth when using arcuate vascular plexus involvement as a marker of deep myometrial infiltration.

Radiological assessment of gynecologic malignancies

Patients with gynecologic malignancies are evaluated with a combination of imaging modalities including ultrasonography (US), computed tomography (CT), and magnetic resonance (MR) imaging. US has a primary role in detecting and characterizing endometrial and adnexal pathology. CT is one of the primary modalities in staging malignancy and detecting recurrence. MR imaging is characterized by superior contrast resolution and specificity. This article reviews the role of radiologic imaging for the characterization of gynecologic masses and for staging, planning, and monitoring treatment, as well as for the assessment of tumor recurrence of the most common gynecologic malignancies.