Diagnostic imaging using positron emission tomography for gynecological malignancy

The OCDA-Net: a 3D convolutional neural network-based system for classification and staging of ovarian cancer patients using [18F]FDG PET/CT examinations

OBJECTIVE

To create the 3D convolutional neural network (CNN)-based system that can use whole-body [18F]FDG PET for recurrence/post-therapy surveillance in ovarian cancer (OC).

METHODS

In this study, 1224 image sets from OC patients who underwent whole-body [18F]FDG PET/CT at Kowsar Hospital between April 2019 and May 2022 were investigated. For recurrence/post-therapy surveillance, diagnostic classification as cancerous, and non-cancerous and staging as stage III, and stage IV were determined by pathological diagnosis and specialists' interpretation. New deep neural network algorithms, the OCDAc-Net, and the OCDAs-Net were developed for diagnostic classification and staging of OC patients using [18F]FDG PET/CT images. Examinations were divided into independent training (75%), validation (10%), and testing (15%) subsets.

RESULTS

This study included 37 women (mean age 56.3 years; age range 36-83 years). Data augmentation techniques were applied to the images in two phases. There were 1224 image sets for diagnostic classification and staging. For the test set, 170 image sets were considered for diagnostic classification and staging. The OCDAc-Net areas under the receiver operating characteristic curve (AUCs) and overall accuracy for diagnostic classification were 0.990 and 0.92, respectively. The OCDAs-Net achieved areas under the receiver operating characteristic curve (AUCs) of 0.995 and overall accuracy of 0.94 for staging.

CONCLUSIONS

The proposed 3D CNN-based models provide potential tools for recurrence/post-therapy surveillance in OC. The OCDAc-Net and the OCDAs-Net model provide a new prognostic analysis method that can utilize PET images without pathological findings for diagnostic classification and staging.

Imaging of colon and rectal cancer

Colon and rectal cancer imaging has traditionally been performed to assess for distant disease (typically lung and liver metastases) and to assess the resectability of the primary tumor. With technological and scientific advances in imaging and the evolution of treatment options, the role of imaging has expanded. Radiologists are now expected to provide a precise description of primary tumor invasion extent, including adjacent organ invasion, involvement of the surgical resection plane, extramural vascular invasion, lymphadenopathy, and response to neoadjuvant treatment, and to monitor for recurrence after clinical complete response.

Current Update on PET/MRI in Gynecological Malignancies-A Review of the Literature

Early detection of gynecological malignancies is vital for patient management and prolonging the patient's survival. Molecular imaging, such as positron emission tomography (PET)/computed tomography, has been increasingly utilized in gynecological malignancies. PET/magnetic resonance imaging (MRI) enables the assessment of gynecological malignancies by combining the metabolic information of PET with the anatomical and functional information from MRI. This article will review the updated applications of PET/MRI in gynecological malignancies.

Diagnostic Value of 18F-FDG PET/MRI for Revised 2018 FIGO Staging in Patients with Cervical Cancer

Purpose: To evaluate the diagnostic potential of PET/MRI with ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) in cervical cancer based on the revised 2018 International Federation of Gynecology and Obstetrics (FIGO) staging system. Materials and Methods: Seventy-two patients with biopsy-proven primary cervical cancer underwent pretreatment ¹⁸F-FDG PET/MRI, CT, and pelvic MRI. The diagnostic performance of ¹⁸F-FDG PET/MRI and MRI for assessing extent of the primary tumor and ¹⁸F-FDG PET/MRI and CT for assessing nodal and distant metastases was evaluated by two experienced readers. Histopathological and follow-up imaging results were used as the gold standard. McNemar test was employed for statistical analysis. Results: Accuracy for the invasion of vagina, parametrium, side wall, and adjacent organs was 97.2%, 93.1%, 97.2%, and 100% for ¹⁸F-FDG PET/MRI; and 97.2%, 91.7%, 97.2%, and 100% for pelvic MRI, respectively (p > 0.05). Patient-based accuracy for metastasis to pelvic and paraaortic lymph nodes and distant organs was 95.8%, 98.6%, and 100% for ¹⁸F-FDG PET/MRI; and 83.3%, 95.8%, and 97.2% for CT, respectively; metastasis to pelvic lymph nodes was statistically significant (p < 0.01). Lesion-based sensitivity, specificity, and accuracy for lymph nodes were 83.3%, 95.9%, and 94.8% for ¹⁸F-FDG PET/MRI; and 29.2%, 98.9% and 93.1% for CT, respectively; sensitivity was statistically significant (p < 0.001). After excluding patients diagnosed by conization, accuracy for revised FIGO staging 2018 was significantly better for ¹⁸F-FDG PET/MRI (82.1%) than for CT and MRI (60.7%) (p < 0.01). Conclusions: ¹⁸F-FDG PET/MRI offers higher diagnostic value for revised 2018 FIGO staging, suggesting that ¹⁸F-FDG PET/MRI might provide an optimal diagnostic strategy for preoperative staging.

Diagnostic value of 18F-FDG PET/MRI for staging in patients with endometrial cancer

Background

Preoperative accurate assessment of endometrial cancer can assist in the planning of additional surgical options, and in predicting the prognosis. The aim of the present study was to evaluate the diagnostic potential of non-contrast PET/MRI with ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) for assessment in preoperative staging of endometrial cancer.

Methods

Thirty-six patients with biopsy-proven endometrial cancer underwent preoperative ¹⁸F-FDG PET/MRI, contrast-enhanced CT (ceCT) and pelvic dynamic contrast-enhanced MRI (ceMRI) for initial staging. The diagnostic performance of ¹⁸F-FDG PET/MRI and ceMRI for assessing the extent of the primary tumor (T stage), and ¹⁸F-FDG PET/MRI and ceCT for assessing nodal (N stage) and distant (M stage) metastasis, was evaluated by two experienced readers. Histopathological and follow-up imaging results were used as the gold standard. The McNemar test was employed for statistical analysis.

Results

Accuracy for T status was 77.8 and 75.0% for ¹⁸F-FDG PET/MRI and ceMRI, respectively. Patient-based accuracy for detecting regional nodal and distant metastasis was 91.3 and 81.8% for ¹⁸F-FDG PET/MRI, and 87.0 and 81.8% for ceCT. None of these parameters was statistically significant (p > 0.05). Lesion-based sensitivity, specificity and accuracy for detecting regional nodal metastasis were 100, 96.9 and 97.0% for ¹⁸F-FDG PET/MRI, and 14.3, 97.6 and 93.3% for ceCT; sensitivity was statistically significant (p < 0.05).

Conclusions

Non-contrast ¹⁸F-FDG PET/MRI, which combines the individual advantages of PET and MRI, offers a high diagnostic value equivalent to that of ceMRI for assessment of the primary tumor, and equivalent to that of ceCT for the assessment of nodal and distant metastatic staging, in patients with endometrial cancer. These findings suggest that ¹⁸F-FDG PET/MRI might provide an alternative diagnostic strategy to conventional imaging modalities in the preoperative staging of endometrial cancer.

Supplementary information

Supplementary information accompanies this paper at 10.1186/s40644-020-00357-4.

Diagnostic value of [18F]FDG PET/MRI for staging in patients with ovarian cancer

Purpose

To evaluate the diagnostic potential of PET/MRI with 2-[¹⁸F]fluoro-2-deoxy-d-glucose ([¹⁸F]FDG) in ovarian cancer.

Materials and methods

Participants comprised 103 patients with suspected ovarian cancer underwent pretreatment [¹⁸F]FDG PET/MRI, contrast-enhanced CT (ceCT) and pelvic dynamic contrast-enhanced MRI (ceMRI). Diagnostic performance of [¹⁸F]FDG PET/MRI and ceMRI for assessing the characterization and the extent of the primary tumor (T stage) and [¹⁸F]FDG PET/MRI and ceCT for assessing nodal (N stage) and distant (M stage) metastases was evaluated by two experienced readers. Histopathological and follow-up imaging results were used as the gold standard. The McNemar test was employed for statistical analysis.

Results

Accuracy for the characterization of suspected ovarian cancer was significantly better for [¹⁸F]FDG PET/MRI (92.5%) [95% confidence interval (CI) 0.84–0.95] than for ceMRI (80.6%) (95% CI 0.72–0.83) (p < 0.05). Accuracy for T status was 96.4% (95% CI 0.96–0.96) and 92.9% (95% CI 0.93–0.93) for [¹⁸F]FDG PET/MRI and ceMRI/ceCT, respectively. Patient-based accuracies for N and M status were 100% (95% CI 0.88–1.00) and 100% (95% CI 0.88–1.00) for [¹⁸F]FDG PET/MRI and 85.2% (95% CI 0.76–0.85) and 30.8% (95% CI 0.19–0.31) for ceCT and M staging representing significant differences (p < 0.01). Lesion-based sensitivity, specificity and accuracy for N status were 78.6% (95% CI 0.57–0.91), 95.7% (95% CI 0.93–0.97) and 93.9% (95% CI 0.89–0.97) for [¹⁸F]FDG PET/MRI and 42.9% (95% CI 0.24–0.58), 96.6% (95% CI 0.94–0.98) and 90.8% (95% CI 0.87–0.94) for ceCT.

Conclusions

[¹⁸F]FDG PET/MRI offers better sensitivity and specificity for the characterization and M staging than ceMRI and ceCT, and diagnostic value for T and N staging equivalent to ceMRI and ceCT, suggesting that [¹⁸F]FDG PET/MRI might represent a useful diagnostic alternative to conventional imaging modalities in ovarian cancer.

Prognostic Value of 16α-18F-Fluoro-17β-Estradiol PET as a Predictor of Disease Outcome in Endometrial Cancer: A Prospective Study

The purpose of this study was to evaluate the potential of 16α-¹⁸F-fluoro-17β-estradiol (¹⁸F-FES) PET to predict prognosis in patients with endometrial cancer (EC). Methods: In total, 67 patients with International Federation of Gynecology and Obstetrics (FIGO) stage I-IV EC underwent ¹⁸F-FES and ¹⁸F-FDG PET/CT before treatment. The SUV_mean of the primary tumor was compared with the clinical characteristics, and the relationships between SUV and progression-free survival (PFS) or overall survival were analyzed. Results: ¹⁸F-FES SUV was significantly associated with stage, histology, lymphovascular space involvement (LVSI), and lymph node metastasis, and ¹⁸F-FDG SUV was significantly associated with stage, myometrial invasion, tumor size, and lymph node metastasis. Receiver-operating characteristic curve analysis revealed that ¹⁸F-FES SUV could significantly detect tumor progression and survival, with areas under the curve of 0.813 and 0.790, respectively, whereas ¹⁸F-FDG SUV could detect them with areas under the curve of 0.557 and 0.635, respectively. The Kaplan-Meier survival curve showed that patients with a low ¹⁸F-FES SUV had significantly poor PFS (P < 0.001) and overall survival (P = 0.001) compared with patients with a high SUV, whereas ¹⁸F-FDG showed no significant differences. In a subanalysis of 27 patients with a low risk of recurrence (FIGO stage IA endometrioid carcinoma [grade 1 or 2] without LVSI), those with a low ¹⁸F-FES SUV also had poorer PFS than those with a high SUV (P = 0.002). In multivariate analysis, an ¹⁸F-FES SUV of less than 2.63 (P = 0.037; hazard ratio, 10.727; 95% CI, 1.16-99.35) and FIGO stages III and IV (P = 0.042; hazard ratio, 8.838; 95% CI, 1.09-71.84) were significantly associated with PFS. Conclusion: A low ¹⁸F-FES for the primary tumor was strongly associated with prognostic factors of EC such as LVSI and lymph node metastasis, and a low ¹⁸F-FES SUV was an independent prognostic factor for PFS in patients with EC. These data suggest that pretreatment ¹⁸F-FES PET might be useful in determining the appropriate treatment for patients with EC.

Prognostic impact of Dynamin related protein 1 (Drp1) in epithelial ovarian cancer

BACKGROUND

The mitochondrial fission protein, Dynamin related protein 1 (Drp1), and its upstream protein calcium/calmodulin-dependent protein kinase I (CaMKI) play a critical role in chemoresistance in ovarian cancer (OVCA). Thus, we examined the expression of Drp1, CaMKI and their phosphorylated forms and their prognostic impact in epithelial OVCA patients.

METHODS

Expression analysis was performed by immunohistochemistry (IHC) of paraffin-embedded tumor samples from 49 patients with epithelial OVCA. Staining intensity and the percentage of positively stained tumor cells were used to calculate an immunoreactive score (IRS) of 0-12. The expression scores calculated were correlated with clinicopathological parameters and patient survival.

RESULTS

High immunoreactivity of phospho-Drp1Ser637 was significantly correlated with high-grade serous carcinoma (HGSC) (p = 0.034), residual postoperative tumor of > 1 cm (p = 0.006), and non-responders to adjuvant chemotherapy (p = 0.007), whereas high expression of CaMKI was significantly correlated with stage III/IV [International Federation of Gynecologists and Obstetricians (FIGO)] (p = 0.011) and platinum-resistant recurrence (p = 0.030). ROC curve analysis showed that Drp1, phospho-Drp1Ser637 and CaMKI could significantly detect tumor progression with 0.710, 0.779, and 0.686 of area under the curve (AUC), respectively. The Kaplan-Meier survival curve showed that patients with high Drp1, phospho-Drp1Ser637 and CaMKI levels had significantly poorer progression free survival (PFS) (p = 0.003, p < 0.001 and p = 0.017, respectively). Using multivariate analyses, phospho-Drp1Ser637 was significantly associated with PFS [p = 0.043, hazard ratio (HR) 3.151, 95% confidence interval (CI) 1.039-9.561].

CONCLUSIONS

Drp1 and CaMKI are novel potential candidates for the detection and prognosis of epithelial OVCA and as such further studies should be performed to exploit their therapeutic significance.

Pretreatment tumor-related leukocytosis misleads positron emission tomography-computed tomography during lymph node staging in gynecological malignancies

The accuracy of fluorine-18-fluorodeoxyglucose positron emission tomography-computed tomography (18F-FDG-PET/CT) can be influenced by the increased glycolytic activity of inflammatory lesions. Here, using clinical data obtained from gynecological cancer patients, tumor samples and animal models, we investigate the impact of pretreatment tumor-related leukocytosis (TRL) on the diagnostic performance of 18F-FDG-PET/CT in detecting pelvic and paraaortic lymph node metastasis. We demonstrate that pretreatment TRL misleads 18F-FDG-PET/CT during lymph node staging in gynecological malignancies. In the mechanistic investigations, we show that the false-positive 18F-FDG-PET/CT result for detecting nodal metastasis can be reproduced in animal models of TRL-positive cancer bearing G-CSF expressing cervical cancer cells. We also show that increased 18F-FDG uptake in non-metastatic nodes can be explained by the MDSC-mediated premetastatic niche formation in which proinflammatory factors, such as S100A8 or S100A9, are abundantly expressed. Together, our results suggest that the MDSC-mediated premetastatic niche created in the lymph node of TRL-positive patients misleads 18F-FDG-PET/CT for detecting nodal metastasis.

Development of a novel and rapid measurement system for growth differentiation factor-15, progranulin, and osteopontin in uterine sarcoma

Uterine sarcomas are rare and aggressive gynecologic tumors with poor prognosis; therefore, early diagnosis is crucial for therapy. However, it is very difficult to distinguish uterine sarcomas from leiomyomas which are common benign uterine tumors. Therefore, the development of a diagnostic method that utilizes reliable biomarkers to distinguish uterine sarcomas from leiomyomas is important so as to identify the rare tumors. The candidate factors as novel biomarkers were searched for in public databases and a pilot study was performed for confirmation. Growth differentiation factor-15 (GDF15), progranulin, and osteopontin were identified as candidate biomarkers for diagnosing uterine sarcoma. Thus, developing a rapid and easy method to measure these factors could help establish a screening system for uterine sarcomas. In this study, we developed a novel measurement system for these factors using a compact chemical luminescence immunological automatic analyzer POCube^TM. This assay system, which is based on the flow-through membrane immunoassay, completes the whole process and generates results within 15 min. Serum concentrations of these factors measured via POCube^TM correlated well with those measured using enzyme-linked immunosorbent assay (r = 0.994 for GDF15, r = 0.992 for progranulin, and r = 0.976 for osteopontin). The POCube^TM system provides rapid and easy measurement of these factors, thereby facilitating uterine sarcoma diagnosis.

Predictive Value of 16α-[18F]-Fluoro-17β-Estradiol PET as a Biomarker of Progestin Therapy Resistance in Patients With Atypical Endometrial Hyperplasia and Low-Grade Endometrial Cancer

For early-stage endometrial cancer patients who wish to preserve fertility, progestin treatment is effective. However, repeated endometrial curettage to evaluate treatment response may cause infertility. The clinical courses of 3 patients who were treated with fertility-sparing progestin treatment and underwent serial F-FES PET before and after treatment are presented. The SUVmean decreased greatly in patients with pathologically complete response (44.2%, 46.2%), whereas there was only a small change (22.5%) in the patient with pathologically stable disease who finally underwent hysterectomy. F-FES PET can be a noninvasive method to evaluate response to fertility-sparing progestin treatment.

Imaging for Peritoneal Metastases

MRI provides considerable advantages for imaging of patients with peritoneal tumor. Its inherently superior contrast resolution compared with computed tomography allows MRI to more accurately depict small peritoneal tumors that are often missed on other imaging tests. Combining different contrast mechanisms, including diffusion-weighted MRI and gadolinium-enhanced MRI, provides a powerful tool for preoperative and surveillance imaging in patients being considered for cytoreductive surgery and heated intraperitoneal chemotherapy.

Precise preoperative diagnosis of struma ovarii with pseudo-Meigs' syndrome mimicking ovarian cancer with the combination of 131I scintigraphy and 18F-FDG PET: case report and review of the literature

Background

Struma ovarii is a rare ovarian neoplasm that often appears malignant on conventional imaging. Pseudo-Meigs’ syndrome with ascites, pleural effusion, and elevated serum CA 125 levels is much rarer and leads to misdiagnosis of ovarian cancer and unnecessary extended surgery.

Case presentation

A 50-year-old woman with abdominal distention and dyspnoea was referred to our hospital. Ultrasound, computed tomography (CT), and magnetic resonance imaging (MRI) showed a polycystic ovarian tumor with a solid component, pleural effusion, and massive ascites with negative cytology. Her serum CA 125 level was 1237 U/ml, indicating the presence of ovarian cancer. Based on increased uptake of ¹³¹I but no uptake of ¹⁸F–FDG in the tumor, the preoperative diagnosis was struma ovarii with pseudo-Meigs’ syndrome, which was confirmed histologically. She had no evidence of ascites and pleural effusion six months after surgery.

Conclusions

To date, there have been no systematic reviews focused on preoperative diagnosis with imaging modalities. The combination of ¹³¹I scintigraphy and ¹⁸F–FDG PET/CT in addition to conventional imaging modalities can provide the precise preoperative diagnosis of struma ovarii with pseudo-Meigs’ syndrome mimicking ovarian cancer, leading to the appropriate treatment strategy.