Qualitative and quantitative analysis of diffusion-weighted imaging of gestational trophoblastic disease: Can it predict progression of molar pregnancy to persistent form of disease?

Gestational trophoblastic disease: an update

Gestational trophoblastic diseases (GTD) encompass a spectrum of rare pre-malignant and malignant entities originating from trophoblastic tissue. This updated review will highlight important radiological features, pathology and classification, and provide insight into the clinical management of these uncommon disorders. There is a wide geographic variation with the incidence of hydatidiform mole varying between 0.57 and 2 per 1000 pregnancies. The use of ultrasound (US) in the management of early pregnancy symptoms and complications has positively impacted the earlier detection of these diseases and resulted in diminished morbidity. Additional imaging modalities are reserved for problem solving or assessment of pulmonary manifestations of molar pregnancy. Having an awareness of their pleomorphic sonographic presentation and additional pathology that can mimic GTD is critical to avoiding pitfalls. Histologic and molecular analysis further aids in differential diagnosis. Gestational trophoblastic neoplasia (GTN) is inclusive of all malignant GTDs, and arises after 20% of molar pregnancies but can also be seen with non-molar gestations. Biochemical monitoring with human chorionic gonadotrophin is imperative for ongoing monitoring and surveillance and allows early detection of this entity. Doppler US is used for confirmation of diagnosis with magnetic resonance imaging (MRI) reserved for problem solving or assessment of myometrial invasion. This is of heightened relevance in patients undergoing surgical management. Cross sectional imaging is reserved for patients in the setting of GTN for the purposes of staging, prognostication and in the setting of recurrent disease. This may require a combination of computed tomography, MRI and positron emission tomography. Doppler US can provide insight into chemotherapeutic response/predict resistance in patients with GTN. As our understanding of these disorders evolves, there has been maturation in management options with a shift from traditional chemotherapy to innovative immunotherapy, particularly in the setting of resistant or high-risk disease.

Does diffusion weighted imaging have a prognostic value in differentiating gynecological diseases?

INTRODUCTION

Apparent diffusion coefficient (ADC) values are effective in the diagnosis of different gynecological lesions.

METHODS

A retrospective evaluation was made of 12 patients with uterine cervix carcinoma and 151 patients with uterine lesions, comprising endometrial cancer, endometrial polyps, carcinosarcoma, submucous myoma, adenomyosis, endometrial hyperplasia, gestational trophoblastic neoplasm (GTN), and leiomyomas. As a control group, 20 healthy volunteers with normal endometrium and normal cervix were also evaluated. In three series, one-shot, spin echo, echo planar, b = 1000 s/mm² value and diffusion-weighted imaging (DWI) were applied to all subjects and ADC values were obtained.

RESULTS

The mean ADC values of Group 1 (Endometrial carcinoma) were lower than those of all the other groups (P < 0.001) and the mean ADC value of group 6 (GTN) was higher than that all other groups (P < 0.001). A statistically significant difference was found between the groups in terms of the lesion-myometrium ADC ratios (P < 0.001).

CONCLUSION

There are few studies in literature related to ADC measurements in GTN. The ADC values of GTN were found to be significantly higher than the other uterine lesions. These results will aid in the design of future studies and might be used to guide management of patients with GTN.

IMPLICATIONS FOR PRACTICE

Diffusion-weighted MRI seems to be a promising imaging technique in differentiating different uterine lesions.

Clinical presentation and diagnosis of Gestational Trophoblastic Disease

Gestational trophoblastic disease (GTD) is a heterogeneous group of pregnancy-related disorders characterized by abnormal proliferation of trophoblastic tissue. It encompasses the premalignant partial and complete hydatidiform mole but also the malignant invasive mole, choriocarcinoma, placental-site trophoblastic tumor, and epithelioid trophoblastic tumor. The clinical presentation changed to earlier detection after the introduction of first trimester ultrasounds. Patients are often asymptomatic, but vaginal bleeding continues to be the most common presenting symptom. Other symptoms can develop in the case of metastatic disease. Ultrasound, serum human chorionic gonadotrophin, and sometimes additional imaging such as CT, MRI, or PET can confirm the diagnosis and stage of disease. Familiarity with the pathogenesis, classification, imaging features, and treatment of GTD facilitates diagnosis and appropriate management.

ACR Appropriateness Criteria® Gestational Trophoblastic Disease

Gestational trophoblastic disease (GTD), a rare complication of pregnancy, includes both benign and malignant forms, the latter collectively referred to as gestational trophoblastic neoplasia (GTN). When metastatic, the lungs are the most common site of initial spread. Beta-human chorionic gonadotropin, elaborated to some extent by all forms of GTD, is useful in facilitating disease detection, diagnosis, monitoring treatment response, and follow-up. Imaging evaluation depends on whether GTD manifests in one of its benign forms or whether it has progressed to GTN. Transabdominal and transvaginal ultrasound with duplex Doppler evaluation of the pelvis are usually appropriate diagnostic procedures in either of these circumstances, and in posttreatment surveillance. The appropriateness of more extensive imaging remains dependent on a diagnosis of GTN and on other factors. The use of imaging to assess complications, typically hemorrhagic, should be guided by the location of clinical signs and symptoms. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Role of hysteroscopy and ultrasound in early identification of post-molar gestational trophoblastic neoplasia

OBJECTIVE

To evaluate the role of hysteroscopy and ultrasound in early identification of gestational trophoblastic neoplasia (GTN) after molar evacuation.

METHODS

This was a prospective study involving 52 women with an ultrasound diagnosis of complete hydatidiform mole, attending a tertiary centre in south India between August 2016 and August 2019. Baseline characteristics such as age, serum beta-human chorionic gonadotropin(β-hCG) level, gestational age, and uterine size were noted. After the evacuation of molar pregnancy, weekly follow-up with β-hCG was performed, until three consecutive values were normal and then monthly for six months. Findings of transvaginal ultrasound and diagnostic hysteroscopy, performed on follow up at three weeks, were noted. Primary outcome was the development of GTN. Area under the curve(AUC) was calculated to assess the usefulness of these methods in early identification of GTN.

RESULTS

Thirteen women (25 %) developed GTN during follow up, within 6 months. Twenty six(50 %) cases had high-risk molar pregnancy. Positive findings on hysteroscopy and ultrasonography were noted in 44.2 % and 19.2 % respectively. AUC was 0.83(95 % CI, 0.70-0.97) for ultrasound and 0.82(95 % CI, 0.72-.92) for hysteroscopy. Sensitivity and specificity were 69.2 % and 97.4 % for ultrasound and it was 92.3 % and 71.8 % respectively for hysteroscopy in identifying those who developed GTN on follow-up.

CONCLUSIONS

Transvaginal ultrasound as well as hysteroscopy may help in early identification of women at risk of developing GTN following a molar evacuation. Being a non-invasive method with similar discriminative value, ultrasonographic evaluation may be used for early identification of women with GTN after validation in future studies.