Performance of integrated FDG-PET/contrast-enhanced CT in the diagnosis of recurrent uterine cancer: comparison with PET and enhanced CT

Evaluating the added value of concurrent contrast-enhanced diagnostic CT for PSMA-PET/CT Interpretation

RATIONALE AND OBJECTIVES

To determine whether concurrent contrast-enhanced diagnostic CT (DxCT) confers added diagnostic certainty compared to PSMA-PET/CT alone.

MATERIALS AND METHODS

This retrospective multi-reader study analyzed imaging comprising combined F-18-piflufolastat PSMA-PET/CT with diagnostic chest/abdominopelvic CT from prostate cancer patients within the first 6 months of FDA-approval of the PET agent. Six nuclear radiology readers were randomly presented with PSMA-PET/CT studies with or without DxCT and asked to report their diagnostic certainty for PSMA-avid lesions found on PET. Subsequently, readers re-reviewed the same study after an interlude (with the CT if not previously presented and vice-versa) to determine if DxCT altered their diagnostic assessment. Inter-rater concordance was assessed on a subset of images read by all readers. Diagnostic certainties for PSMA-PET/CT with and without DxCT were compared, and the variables for which DxCT may add value were examined.

RESULTS

Good inter-rater concordance across readers was noted for both PET/CT (Finn's coefficient of reliability for overall scan certainty: 0.85,p < 0.01) and combined DxCT-PET/CT (0.59,p < 0.01). Overall certainty and concordance between PET/CT and combined DxCT-PET/CT datasets were similar (overall scan certainty: 92% ± 16 vs. 92% ± 17,p = 0.43), with no significant advantage for adding DxCT across different anatomic locations or clinical parameters. A slight predilection for combined DxCT-PET/CT was noted when interpreting images acquired for the initial staging of prostate cancer (89% ± 16 vs. 93% ± 17,p = 0.08).

CONCLUSION

Good inter-reader concordance can be achieved across different training levels with PSMA-PET/CT. Furthermore, using DxCT concurrent with PSMA-PET/CT does not significantly improve diagnostic certainty for most indications but may be useful for initial staging.

Comprehensive literature review of oral and intravenous contrast-enhanced PET/CT: a step forward?

The integration of diagnostic CT scans into PET/CT facilitates a comprehensive single examination, presenting potential advantages for patients seeking a thorough one-shot check-up. The introduction of iodinated contrast media during PET scanning raises theoretical concerns about potential interference with uptake quantification, due to the modification of tissue density on CT. Nevertheless, this impact appears generally insignificant for clinical use, compared to the intrinsic variability of standardized uptake values. On the other hand, with the growing indications of PET, especially 18F-FDG PET, contrast enhancement increases the diagnostic performances of the exam, and provides additional information. This improvement in performance achieved through contrast-enhanced PET/CT must be carefully evaluated considering the associated risks and side-effects stemming from the administration of iodinated contrast media. Within this article, we present a comprehensive literature review of contrast enhanced PET/CT, examining the potential impact of iodinated contrast media on quantification, additional side-effects and the pivotal clinically demonstrated benefits of an all-encompassing examination for patients. In conclusion, the clinical benefits of iodinated contrast media are mainly validated by the large diffusion in PET protocols. Contrary to positive oral contrast, which does not appear to offer any major advantage in patient management, intravenous iodine contrast media provides clinical benefits without significant artifact on images or quantification. However, studies on the benefit-risk balance for patients are still lacking.

The value of intravenous contrast medium in PSMA PET/CT imaging in patients with biochemical recurrence of prostate cancer

PURPOSE

To investigate the added value of diagnostic abdominal contrast-enhanced computed tomography (ceCT) in Ga-68 PSMA PET/CT in prostate cancer patients with biochemical recurrence (BCR).

METHODS

Eighty-two consecutive patients (median age, 69 years; range, 45-86 years) with BCR underwent Ga-68 PSMA PET/CT with low-dose nonenhanced (ne) whole-body CT and diagnostic ceCT. Imaging results were retrospectively reviewed by two readers (R1, R2) for diagnostic certainty, local recurrence, lymph node metastasis (LNM) and bone metastasis. Interobserver agreement was assessed. Histopathology served as reference standard in 7, imaging and clinical follow-up in 65 and clinical follow-up alone in 10 patients.

RESULTS

Certain local recurrence, LNM and bone metastasis diagnoses increased substantially from ceCT (R1: 5%/18%/32%; R2: 37%/50%/82%) to nePET/CT (R1: 78%/87%/93%; R2: 81%/87%/95%) for both readers, but the difference between nePET/CT and cePET/CT (R1: 77%/96%/92%; R2: 89%/94%/96%) was marginal. Interobserver agreement was minimal with ceCT (Krippendorff's alpha: 0.04-0.26), substantial with nePET/CT (0.60-0.86) and best with cePET/CT (0.76-0.86). The areas under the receiver operating characteristic curve (AUCs) for local recurrence for R1/R2 were 0.60/0.65 for ceCT, 0.81/0.79 for nePET/CT and 0.81/0.82 for cePET/CT. AUCs for LNMs for R1/R2 were 0.67/0.77 for ceCT, 0.91/0.82 for nePET/CT and 0.92/0.87 for cePET/CT. AUCs for BMs for R1/R2 were 0.60/0.53 for ceCT, 0.93/0.84 for nePET/CT and 0.93/0.86 for cePET/CT.

CONCLUSION

Diagnostic abdominal ceCT increases the diagnostic certainty and interobserver agreement in Ga-68 PSMA PET/CT in BCR of prostate cancer. The diagnostic performance of cePET/CT is significantly better than ceCT alone but not nePET/CT.

Complementary imaging of ultrasound and PET/CT: A new opportunity?

AIM

To evaluate the effectiveness of complementary imaging of high-resolution ultrasound including CEUS with PET/CT for tissue characterization and tumor detection.

MATERIAL AND METHODS

100 patients were examined with PET/CT and US/CEUS between January 2018 until February 2020. All patients underwent PET/CT followed by selective US/CEUS within 4 weeks. Comparison regarding concordant or diverging findings in PET/CT and US. Analysis of the differences concerning the lesions number of found by PET/CT and US/CEUS or the possibility of a secured diagnosis following ultrasound causing therapeutic changes.

RESULTS

Diverging findings regarding the number of liver lesions in PET/CT and CEUS were found in 35 out of 64 patients (54%). Regarding renal lesions, a more definite diagnosis following ultrasound, causing a change of therapeutic approach, was achieved in 89%. Concordant results in PET/CT and US were found in 83% of patients with splenic and nodal findings. In 78% of patients with increased musculoskeletal or soft tissue tracer uptake, US was able to make a secured diagnosis with therapeutic changes.

CONCLUSION

The present results indicate a strong benefit of complementary imaging of PET/CT and selective, high-resolution ultrasound especially in patients with liver, renal and musculoskeletal or soft tissue findings.

Endometrial Cancer, the Current International Federation of Gynecology and Obstetrics Staging System, and the Role of Imaging

Imaging plays a crucial role in the diagnosis, staging, and follow-up of endometrial cancer. Endometrial cancer is staged surgically using the International Federation of Gynecology and Obstetrics (FIGO) staging system. Preoperative imaging can complement surgical staging but is not yet considered a required component in the current FIGO staging system. Preoperative imaging can help identify some tumor characteristics and tumor spread, both locally and distally. More accurate assessment of endometrial cancers optimizes management and treatment plan, including degree of surgical intervention. In this article, we review the epidemiology, FIGO staging system, and the importance of imaging in the staging of endometrial cancer.

Clinical utility of FDG-PET/CT for post-surgery surveillance of malignant pleural mesothelioma - Comparison with contrast-enhanced CT

Objectives

To assess the diagnostic accuracy of fluorodeoxyglucose (FDG)-positron emission tomography/computed tomography (PET/CT) findings for recurrent malignant pleural mesothelioma (MPM) after a radical surgery procedure and their impact on clinical management in comparison with contrast-enhanced CT.

Results

Treatment failure was confirmed in 40 patients. The patient-based area under the receiver-operating characteristic (ROC) curves (AUC)/sensitivity/specificity/accuracy were 0.915/90.0%/80.0%/88.0% for FDG-PET/CT, and 0.805/75.0%/90.0%/78.0% for contrast-enhanced CT, respectively. AUC and sensitivity values were significantly different between the modalities (both p=0.041). Patient-based AUC values for diagnosing locoregional recurrence (ipsilateral hemithoracic recurrence) and distant metastasis, including peritoneal dissemination and lung, bone, muscle, and liver metastasis, were also significantly different (p=0.023 and p=0.035, respectively). The findings of FDG-PET/CT resulted in a change of management for 14 of the 50 patients (28%) by initiating new treatment. Of six patients judged as not having recurrence by contrast-enhanced CT but truly having recurrence based on FDG-PET/CT findings, 4 patients received new treatment due toFDG-PET/CT.

Methods

Fifty patients who underwent radical surgery for MPM received FDG-PET/CT and contrast-enhanced neck/chest/abdomen/pelvis CT examinations for surveillance or suspected recurrence within a 2-week period. Diagnostic ability was determined on a patient and lesion-site basis by 2 experienced examiners, and the modalities were compared using ROC analysis and McNemar test results. Lesion status was determined on the basis of histopathology, radiological imaging and clinical follow-up for longer than 6 months.

Conclusion

FDG-PET/CT findings were shown to be more accurate for assessing MPM recurrence and more often led to therapy change than contrast-enhanced CT.

PET/MR Imaging of the Female Pelvis

High-quality imaging diagnostics play a fundamental role in patient and therapy management of cancers of the female pelvis. Magnetic resonance imaging (MRI) and positron emission tomography (PET) represent two important imaging modalities, which are frequently applied for primary tumor evaluation, therapy monitoring, and assessment of potential tumor relapse. Based on its high soft-tissue contrast, MRI has been shown superior toward CT for the determination of the local extent of primary tumors and for the differentiation between post-therapeutic changes and tumor relapse. Molecular imaging utilizing ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) PET facilitates an insight into tumor metabolism depending on the glycolytic activity of tumorous cells. As the current gold standard of hybrid imaging, ¹⁸F-FDG-PET/CT has been demonstrated highly accurate and superior to conventional imaging modalities for the detection of tumorous tissue due to the combined analysis of metabolic and morphologic data. Therefore, ¹⁸F-FDG-PET has emerged to become a well-established imaging modality for the detection, re-/staging and therapy response monitoring of a variety of solid tumors, including gynecologic cancers. Integrated PET/MRI systems have been successfully introduced into scientific and clinical applications within the past 8 years. This new-generation hybrid imaging technology enables the simultaneous acquisition of PET- and MR Datasets, providing complementary metabolic, functional, and morphologic information of tumorous tissue. Combining the high soft-tissue contrast of MRI and the metabolic information derived from PET, PET/MRI bears the potential to be utilized as an accurate and efficient diagnostic tool for primary tumor staging, therapy monitoring and restaging of tumors of the female pelvis and plays a valuable role in the management of targeted tumor therapies in the future.

Diagnostic value of 18F-FDG PET/MRI in recurrent pelvis malignancies of female patients: a systematic review and meta-analysis

The aim of this study was to assess the diagnostic performance of fluorine-18-fluorodeoxyglucose (F-FDG) PET/MRI for suspected recurrence of pelvis malignancies of female patients using a meta-analysis. We performed a systematical literature search for relevant studies in PubMed, Cochrane Library, Google Scholar, and several Chinese databases. Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) was used to assess the quality of all included studies. Pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio were calculated per patient and per lesion. Summary receiver operating characteristic curves were also constructed. All procedures involving human participants in this study were performed in conformity with the ethical standards of the institutional research committee and with the 1964 Helsinki Declaration and its later amendments. Finally, seven articles comprising 257 patients and 695 lesions were included in this meta-analysis. On patient-based analysis, the pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio of F-FDG PET/MRI in detecting recurrence of pelvis malignancies were 0.96 [95% confidence interval (CI): 0.93-0.99], 0.95 (95% CI: 0.87-0.99), 9.85 (95% CI: 4.62-21.00), 0.07 (95% CI: 0.04-0.13), and 201.41 (95% CI: 62.89-645.03), respectively. On lesion-based analysis, the corresponding estimates were 0.99 (95% CI: 0.97-1.00), 0.94 (95% CI: 0.89-0.97), 17.11 (95% CI: 4.46-65.60), 0.02 (95% CI: 0.01-0.05), and 1125.24 (95% CI: 211.46-5987.79), respectively. The results of our meta-analysis indicate that F-FDG PET/MRI has excellent diagnostic performance in restaging female patients with suspected recurrence of gynecological pelvic malignancies.

FDG-PET Assessment of Other Gynecologic Cancers

PET and PET/computed tomography play a role in the staging, monitoring of response to therapy, and surveillance for cervical and ovarian cancers. Currently, it is also an integral part of the assessment of patients with endometrial cancer and other gynecologic malignancies, such as vaginal and vulvar cancers and uterine sarcomas. In this article, we discuss in detail and highlight the potential role of PET and PET/computed tomography in evaluating these gynecologic malignancies using illustrative cases with relevant imaging findings.

Inflammatory and Ischemic Post Liver Transplant Complications Mimic Malignancy on 18F-FDG PET/CT

A 65-year-old male patient with a one year history of liver transplantation was referred for an ¹⁸F-fluoro-2-deoxy-D-glucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) to rule out post transplant lymphoproliferative disease. Multiple foci of intense abnormal ¹⁸F-FDG uptake were seen in the transplanted liver which were concerning for malignancy. Explantation of the liver approximately 1 month following the PET/CT revealed multiple inflammatory and ischemic changes including large bile duct necrosis, acute cholangitis, bile duct obstruction changes and periportal fibrosis, with no evidence of malignancy. We present the ¹⁸F-FDG PET/CT image findings of this case.

Comparison of FDG PET metabolic tumour volume versus ADC histogram: prognostic value of tumour treatment response and survival in patients with locally advanced uterine cervical cancer

OBJECTIVE

To evaluate the prognostic utility of volume-based parameters of fluorine-18 fludeoxyglucose positron emission tomography (¹⁸F-FDG PET) and apparent diffusion coefficient (ADC) histogram analysis for tumour response to therapy and event-free survival (EFS) in patients with uterine cervical cancer receiving chemoradiotherapy.

METHODS

The study included 21 patients diagnosed with locally advanced uterine cervical cancer who underwent pre-treatment MRI and ¹⁸F-FDG PET and were treated with concurrent chemoradiotherapy. ¹⁸F-FDG parameters: maximum and mean standardized uptake value; metabolic tumour volume (MTV); total lesion glycolysis (TLG); ADC parameters: maximum, mean and minimum values; percentile ADC values (10-90%); skewness and kurtosis of ADC were measured and compared between the responder and non-responder groups using a Wilcoxon rank-sum test. The Cox regression analysis and Kaplan-Meier survival curves were performed for EFS analysis.

RESULTS

MTV and TLG of the primary tumour were significantly higher in the non-responder group than in the responder group (p = 0.04 and p = 0.01). Applying Cox regression multivariate analysis, MTV [hazard ratio (HR), 4.725; p = 0.036], TLG (HR, 4.725; p = 0.036) and 10-percentile ADC (HR, 5.207; p = 0.048) showed a statistically significant association with EFS. With the optimal cut-off value, the EFS rates above the cut-off value for MTV and TLG were significantly lower than that below the cut-off value (p = 0.002 and p = 0.002).

CONCLUSION

Pre-treatment volume-based quantitative parameters of ¹⁸F-FDG PET may have better potential than ADC histogram for predicting treatment response and EFS in patients with locally advanced cervical cancer. Advances in knowledge: In this study, pre-treatment volume-based quantitative parameters of ¹⁸F-FDG PET had better potential than ADC histogram for predicting treatment response and survival in patients with locally advanced cervical cancer.

Pelvic exenteration case series: A single surgeon's experience at one institution in Trinidad and Tobago

INTRODUCTION

Pelvic exenteration (PE) is an ultra-radical surgical procedure characterized by the en bloc resection of the pelvic organs.

METHODS

In this case series, we report retrospectively on four patients who underwent PE in Trinidad and Tobago from 2012 to 2016. One male patient had rectal cancer while one each of three women had cervical, colon, or rectal cancer.

RESULTS

Early postoperative complications (≤30days) occurred in all patients, while late complications (>30days) occurred in one patient (Grade 1 - Clavien-Dindo classification). Disease recurrence occurred in 50% of patients, and the median overall survival was 8 months (range, 4-15 months).

DISCUSSION

There are many inherent challenges to conducting such major procedures in developing countries, including inadequate blood product supplies, intensive care unit beds, and pre- and post-operative support services. With increased surgical capacity and support infrastructure, hospitals in these regions would be equipped to perform PEs with better outcomes.

CONCLUSION

This case series adds to existing data on the feasibility of performing PE in developing countries. We demonstrate that PE can be performed without major postoperative complications in a resource-limited hospital. To the best of our knowledge, this is the first case series that describes PE in the Caribbean.

Whole-body staging of female patients with recurrent pelvic malignancies: Ultra-fast 18F-FDG PET/MRI compared to 18F-FDG PET/CT and CT

Objectives

To evaluate the diagnostic feasibility of an ultra-fast ¹⁸F-FDG PET/MRI protocol, including T2-w and contrast-enhanced T1-w imaging as well as metabolic assessment (PET) in comparison to ¹⁸F-FDG PET/CT and CT for whole-body staging of female patients with suspected recurrence of pelvic malignancies.

Methods

43 female patients with suspected tumor recurrence were included in this study. Suspicion was based on clinical follow-up and abnormal findings on imaging follow-up. All patients underwent a PET/CT and a subsequent PET/MRI examination. Two readers were asked to evaluate ultra-fast PET/MRI, PET/CT as well as CT datasets of PET/CT separately for suspect lesions regarding lesion count, lesion localization and lesion characterization. Statistical analyses were performed both, on a per-patient and a per-lesion basis.

Results

Tumor relapse was present in 38 of the 43 patients. Based on CT readings 25/38 tumor relapses were correctly identified. PET/CT enabled correct identification of 37/38 patients, PET/MRI correctly identified 36 of the 38 patients with recurrent cancer. On a lesion-based analysis PET/MRI enabled the correct detection of more lesions, comprising a lesion-based sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy of 50%, 58%, 76%, 31%, and 53% for CT, 97%, 83%, 93%, 94%, and 92% for PET/CT and 98%, 83%, 94%, 94%, and 94% for PET/MRI, respectively. Mean scan duration of ultra-fast PET/MRI, PET/CT and whole-body CT amounted to 18.5 ± 1 minutes, 18.2 ± 1 minutes and 3.5 minutes, respectively.

Conclusion

Ultra-fast PET/MRI provides equivalent diagnostic performance and examination time when compared to PET/CT and superior diagnostic performance to CT in restaging female patients suspected to have recurrent pelvic cancer.

State-of-the-Art Treatment and Novel Agents in Local and Distant Recurrences of Cervical Cancer

Depending on the stage at initial presentation, cervical cancer will recur in 25-61% of women. Typical manifestations of recurrent cervical cancer include the central pelvis and the pelvic side walls as well as retroperitoneal lymph node basins in the pelvis and the para-aortic region, and - more rarely - supraclavicular lymph nodes. There are no typical symptoms of recurrent cervical cancer. Women with suspected recurrence after cervical cancer based on gynecological examination or organ-specific symptoms must undergo imaging studies and - if technically feasible - biopsy with histological verification, especially in cases of distant metastases, in order to rule out a second primary. Radiotherapy-naïve women should be treated with salvage radiochemotherapy with curative intention. For women with previous radiotherapy, surgery in the form of hysterectomy, local resection, or pelvic exenteration is the treatment of choice. Pelvic exenteration can lead to cure in selected patients, but at the price of a high rate of complications and significant morbidity and mortality. If complete surgical resection is not feasible or if the woman is not a candidate for surgery, chemotherapy with palliative intent should be offered. Patients with recurrent disease outside the pelvis are candidates for systemic chemotherapy. Several agents have shown to be active in this situation, either in single-agent or combination regimens. Platinum-containing regimens have a superior efficacy over non-platinum regimens and bevacizumab may be added to chemotherapy.

Implementation of FAST-PET/MRI for whole-body staging of female patients with recurrent pelvic malignancies: A comparison to PET/CT

OBJECTIVES

To compare the diagnostic competence of FAST-PET/MRI and PET/CT for whole-body staging of female patients suspect for a recurrence of a pelvic malignancy.

METHODS

24 female patients with a suspected tumor recurrence underwent a PET/CT and subsequent PET/MRI examination. For PET/MRI readings a whole-body FAST-protocol was implemented. Two readers separately evaluated the PET/CT and FAST PET/MRI datasets regarding identification of all tumor lesions and qualitative assessment of visual lesion-to-background contrast (4-point ordinal scale).

RESULTS

Tumor relapse was present in 21 of the 24 patients. Both, PET/CT and PET/MRI allowed for correct identification of tumor recurrence in 20 of 21 cases. Lesion-based sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy for the detection of malignant lesions were 82%, 91%, 97%, 58% and 84% for PET/CT and 85%, 87%, 96%, 63% and 86% for PET/MRI, lacking significant differences. Furthermore, no significant difference for lesion-to-background contrast of malignant and benign lesions was found.

CONCLUSION

FAST-PET/MRI provides a comparably high diagnostic performance for restaging gynecological cancer patients compared to PET/CT with slightly prolonged scan duration, yet enabling a markedly reduced radiation exposure.

Integrated PET/MRI for whole-body staging of patients with primary cervical cancer: preliminary results

PURPOSE

To assess the diagnostic value of integrated PET/MRI for whole-body staging of cervical cancer patients, as well as to investigate a potential association between PET/MRI derived functional parameters and prognostic factors of cervical cancer.

METHODS

The present study was approved by the local institutional review board. Twenty-seven patients with histopathologically confirmed cervical cancer were prospectively enrolled in our study. All patients underwent a whole-body PET/MRI examination after written informed consent was obtained. Two radiologists separately evaluated the PET/MRI data sets regarding the determination of local tumor extent of primary cervical cancer lesions, as well as detection of nodal and distant metastases. Furthermore, SUV and ADC values of primary tumor lesions were analyzed and correlated with dedicated prognostic factors of cervical cancer. Results based on histopathology and cross-sectional imaging follow-up served as the reference standard.

RESULTS

PET/MRI enabled the detection of all 27 primary tumor lesions of the uterine cervix and allowed for the correct determination of the T-stage in 23 (85 %) out of the 27 patients. Furthermore, the calculated sensitivity, specificity and diagnostic accuracy for the detection of nodal positive patients (n = 11) were 91 %, 94 % and 93 %, respectively. PET/MRI correctly identified regional metastatic disease (N1-stage) in 8/10 (80 %) patients and non-regional lymph node metastases in 5/5 (100 %) patients. In addition, quantitative analysis of PET and MRI derived functional parameters (SUV; ADC values) revealed a significant correlation with pathological grade and tumor size (p < 0.05).

CONCLUSIONS

The present study demonstrates the high potential of integrated PET/MRI for the assessment of primary tumor and the detection of lymph node metastases in patients with cervical cancer. Providing additional prognostic information, PET/MRI may serve as a valuable diagnostic tool for cervical cancer patients in a pretreatment setting.

Simultaneous positron emission tomography/magnetic resonance imaging for whole-body staging in patients with recurrent gynecological malignancies of the pelvis: a comparison to whole-body magnetic resonance imaging alone

OBJECTIVES

The objective of this study was to assess the diagnostic value of integrated positron emission tomography/magnetic resonance imaging (PET/MRI) for whole-body staging of patients with recurrent gynecological pelvic malignancies, in comparison to whole-body MRI alone.

MATERIALS AND METHODS

The study was approved by the local institutional ethics committee. Written informed consent was obtained before each examination. Thirty-four consecutive patients with a suspected recurrence of cervical (n = 18) or ovarian (n = 16) cancer were prospectively enrolled for an integrated PET/MRI examination, which comprised a diagnostic, contrast-enhanced whole-body MRI protocol including dedicated sagittal dynamic imaging of the pelvis. Two radiologists separately evaluated the data sets regarding lesion count, lesion detection, lesion characterization, and diagnostic confidence. Mean and median values were calculated for each rating. Statistical analyses were performed both per-patient and per-lesion bases using a Wilcoxon signed-rank test to indicate potential significant differences among PET/MRI and MRI (alone) data sets.

RESULTS

Malignant lesions were present in 25 of the 34 patients. Positron emission tomography/magnetic resonance imaging offered correct and superior identification of all 25 patients with cancer recurrence, compared with MRI alone (23/25). A total of 118 lesions (malignant, 89; benign, 29) were detected. Positron emission tomography/magnetic resonance imaging correctly identified 88 (98.9%) of 89 malignant lesions, whereas MRI alone allowed for correct identification of 79 (88.8%) of the 89 malignant lesions. In addition, PET/MRI provided significantly higher lesion contrast and diagnostic confidence in the detection of malignant lesions (P < 0.001) compared with MRI alone.

CONCLUSIONS

These first results demonstrate the high diagnostic potential of integrated PET/MRI for the assessment of recurrence of female pelvic malignancies compared with MRI alone.

Imaging in endometrial carcinoma

Endometrial carcinoma (EC) is the most common gynecologic malignancy in the United States. Prognosis depends on patient age, histological grade, depth of myometrial invasion and/or cervical invasion, and the presence of lymph node metastases. Although EC is staged surgically according to the International Federation of Gynecology and Obstetrics (FIGO) system, preoperative imaging can assist in optimal treatment planning. Several imaging techniques such as transvaginal ultrasonography (TVUS), computed tomography (CT), and magnetic resonance imaging (MRI) have been used as diagnostic tools for preoperative staging of EC. Recently, positron emission tomography (PET), PET/CT, and PET/MRI have also been used in staging these patients. In this article, we review the value of imaging in diagnosis, staging, treatment planning, and detection of recurrent disease in patients with EC.

Diagnostic value of diffusion-weighted imaging in simultaneous 18F-FDG PET/MR imaging for whole-body staging of women with pelvic malignancies

The aim of this study was to assess the diagnostic benefit of diffusion-weighted imaging (DWI) in an (18)F-FDG PET/MR imaging protocol for whole-body staging of women with primary or recurrent malignancies of the pelvis.

METHODS

Forty-eight patients with a primary pelvic malignancy or suspected recurrence of a pelvic malignancy were included in our study. All patients underwent a whole-body (18)F-FDG PET/MR imaging examination that included DWI. Two radiologists separately evaluated the PET/MR imaging datasets without DWI followed by a second interpretation with DWI. First, both readers identified all primary tumors, as well as lymph node and distant metastases. In a second session, PET and DWI data were assessed qualitatively. Image interpretation comprised lesion conspicuity defined as visual lesion-to-background contrast (4-point ordinal scale) and diagnostic confidence (3-point ordinal scale) for all tumors. The results from histopathologic examination and cross-sectional imaging follow-up (≥6 mo) were used as the reference standard. Statistical analysis was performed to assess the significance of differences between obtained values.

RESULTS

Among the 122 suspected lesions seen, 98 (80.3%) were considered malignant. PET/MR imaging without DWI had a sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy of 92.9%, 87.5%, 96.8%, 75.0%, and 91.8%, respectively, for the detection of malignant lesions. PET/MR imaging with DWI had slightly higher values (94.9%, 83.3%, 95.9%, 80.0%, and 92.6%, respectively), but the difference was not significant (P > 0.05). In the qualitative assessment of lesion-to-background contrast, PET had significantly (P < 0.05) higher values (3.79 ± 0.58) than DWI (3.63 ± 0.77). Furthermore, significantly (P < 0.05) higher scores were found for diagnostic confidence using PET (2.68 ± 0.64) for the determination of malignant lesions, when compared with DWI (2.53 ± 0.69).

CONCLUSION

DWI in PET/MR imaging has no diagnostic benefit for whole-body staging of women with pelvic malignancies. The omission of DWI for staging or restaging gynecologic cancer may significantly reduce examination times, thus increasing patient comfort without a relevant decrease in diagnostic competence.

Correlation of standardized uptake value and apparent diffusion coefficient in integrated whole-body PET/MRI of primary and recurrent cervical cancer

Background

To evaluate a potential correlation of the maximum standard uptake value (SUV_max) and the minimum apparent diffusion coefficient (ADC_min) in primary and recurrent cervical cancer based on integrated PET/MRI examinations.

Methods

19 consecutive patients (mean age 51.6 years; range 30–72 years) with histopathologically confirmed primary cervical cancer (n = 9) or suspected tumor recurrence (n = 10) were prospectively enrolled for an integrated PET/MRI examination. Two radiologists performed a consensus reading in random order, using a dedicated post-processing software. Polygonal regions of interest (ROI) covering the entire tumor lesions were drawn into PET/MR images to assess SUV_max and into ADC parameter maps to determine ADC_min values. Pearson’s correlation coefficients were calculated to assess a potential correlation between the mean values of ADC_min and SUV_max.

Results

In 15 out of 19 patients cervical cancer lesions (n = 12) or lymph node metastases (n = 42) were detected. Mean SUV_max (12.5±6.5) and ADC_min (644.5±179.7×10⁻⁵ mm²/s) values for all assessed tumor lesions showed a significant but weak inverse correlation (R = −0.342, p<0.05). When subdivided in primary and recurrent tumors, primary tumors and associated primary lymph node metastases revealed a significant and strong inverse correlation between SUV_max and ADC_min (R = −0.692, p<0.001), whereas recurrent cancer lesions did not show a significant correlation.

Conclusions

These initial results of this emerging hybrid imaging technique demonstrate the high diagnostic potential of simultaneous PET/MR imaging for the assessment of functional biomarkers, revealing a significant and strong correlation of tumor metabolism and higher cellularity in cervical cancer lesions.

Which imaging technique should we use in the follow up of gynaecological cancer?

Follow-up routines after gynaecological cancer vary. The optimal approach is unknown, and no randomised-controlled trials comparing surveillance protocols have been published. In this chapter, we summarise the diagnostic performance of ultrasound, computed tomography, and magnetic resonance imaging in the follow up of women treated for ovarian or uterine cancers. Computed tomography is today the standard imaging method for the follow up of women treated for endometrial, cervical, or ovarian cancer. Six-monthly or annual follow-up examinations have not been shown to positively affect survival. Instead, a combination of transvaginal and transabdominal ultrasound examination with clinical examination might be a more cost-effective strategy for early detection of recurrence. Positron-emission tomography might play a role in women with clinical or serological suspicion of recurrence but without evidence of disease at conventional diagnostic imaging. To create guidelines, more studies, preferably randomised-controlled trials, on follow-up strategies are needed.

Value of fusion of PET and MRI in the detection of intra-pelvic recurrence of gynecological tumor: comparison with 18F-FDG contrast-enhanced PET/CT and pelvic MRI

Background

To evaluate the diagnostic value of retrospective image fusion from pelvic magnetic resonance imaging (MRI) and ¹⁸F-fluorodeoxyglucose positron emission tomography (PET) in detecting intra-pelvic recurrence of gynecological tumor.

Methods

Thirty patients with a suspicion of recurrence of gynecological malignancy underwent inline contrast-enhanced PET/computed tomography (CT) and pelvic contrast-enhanced MRI for restaging. Diagnostic performance about the local recurrence, pelvic lymph node and bone metastasis and peritoneal lesion of PET/low-dose non-enhanced CT (PET/ldCT), PET/full-dose contrast-enhanced CT (PET/ceCT), contrast-enhanced MRI, and retrospective image fusion from PET and MRI (fused PET/MRI) were evaluated by two experienced readers. Final diagnoses were obtained by histopathological examinations, radiological imaging and clinical follow-up for at least 6 months. McNemar test was employed for statistical analysis.

Results

Documented positive locally recurrent disease, pelvic lymph node and bone metastases, and peritoneal dissemination were present in 53.3, 26.7, 10.0, and 16.7 %, respectively. Patient-based sensitivity for detecting local recurrence, pelvic lymph node and bone metastasis and peritoneal lesion were 87.5, 87.5, 100 and 80.0 %, respectively, for fused PET/MRI, 87.5, 62.5, 66.7 and 60.0 %, respectively, for contrast-enhanced MRI, 62.5, 87.5, 66.7 and 80.0 %, respectively, for PET/ceCT, and 50.0, 87.5, 66.7 and 60.0 %, respectively, for PET/ldCT. The sensitivity of diagnosing local recurrence by fused PET/MRI was significantly better than that of PET/ldCT (p = 0.041). The patient-based sensitivity, specificity and accuracy for the detection of intra-pelvic recurrence/metastasis were 91.3, 100 and 93.3 % for fused PET/MRI, 82.6, 100 and 86.7 % for contrast-enhanced MRI, 82.6, 100 and 86.7 % for PET/ceCT and 78.3, 85.7 and 80.0 % for PET/ldCT.

Conclusion

Fused PET/MRI combines the individual advantages of MRI and PET, and is a valuable technique for assessment of intra-pelvic recurrence of gynecological cancers.

The added role of MR imaging in treatment stratification of patients with gynecologic malignancies: what the radiologist needs to know

Many treatment options are available to patients with endometrial, cervical, or ovarian cancer. Magnetic resonance (MR) imaging plays an important role in the patient journey from the initial evaluation of the extent of the disease to appropriate treatment selection and follow-up. The purpose of this review is to highlight the added role of MR imaging in the treatment stratification and overall care of patients with endometrial, cervical, or ovarian cancer. Several MR imaging techniques used in evaluation of patients with gynecologic malignancies are described, including both anatomic MR imaging sequences (T1- and T2-weighted sequences) and pulse sequences that characterize tissue on the basis of physiologic features (diffusion-weighted MR imaging), dynamic contrast agent-enhanced MR imaging, and MR spectroscopy. MR imaging findings corresponding to the 2009 revised International Federation of Gynecology and Obstetrics staging of gynecologic malignancies are also described in detail, highlighting possible pearls and pitfalls of staging. With the growing role of the radiologist as a core member of the multidisciplinary treatment planning team, it is crucial for imagers to recognize that MR imaging has become central in tailoring treatment options and therapy in patients with gynecologic malignancies.

Impact of 18F-FDG PET/CT on target volume delineation in recurrent or residual gynaecologic carcinoma

Background

To evaluate the impact of ¹⁸F-FDG PET/CT on target volume delineation in gynaecological cancer.

Methods

F-FDG PET/CT based RT treatment planning was performed in 10 patients with locally recurrent (n = 5) or post-surgical residual gynaecological cancer (n = 5). The gross tumor volume (GTV) was defined by 4 experienced radiation oncologists first using contrast enhanced CT (GTV_CT) and secondly using the fused ¹⁸F-FDG PET/CT datasets (GTV_PET/CT). In addition, the GTV was delineated using the signal-to-background (SBR) ratio-based adaptive thresholding technique (GTV_SBR). Overlap analysis were conducted to assess geographic mismatches between the GTVs delineated using the different techniques. Inter- and intra-observer variability were also assessed.

Results

The mean GTV_CT (43.65 cm³) was larger than the mean GTV_PET/CT (33.06 cm³), p = 0.02. In 6 patients, GTV_PET/CT added substantial tumor extension outside the GTV_CT even though 90.4% of the GTV_PET/CT was included in the GTV_CT and 30.2% of the GTV_CT was found outside the GTV_PET/CT. The inter- and intra-observer variability was not significantly reduced with the inclusion of ¹⁸F-FDG PET imaging (p = 0.23 and p = 0.18, respectively). The GTV_SBR was smaller than GTV_CT p ≤ 0.005 and GTV_PET/CT p ≤ 0.005.

Conclusions

The use of ¹⁸F-FDG PET/CT images for target volume delineation of recurrent or post-surgical residual gynaecological cancer alters the GTV in the majority of patients compared to standard CT-definition. The use of SBR-based auto-delineation showed significantly smaller GTVs. The use of PET/CT based target volume delineation may improve the accuracy of RT treatment planning in gynaecologic cancer.

A case series of low dose bevacizumab and chemotherapy in heavily pretreated patients with epithelial ovarian cancer

BACKGROUND

The addition of bevacizumab to standard chemotherapy prolongs progression free survival in the first line treatment of epithelial ovarian cancer (EOC), but its cost/effectiveness is debated. We assessed the safety and activity of a lower dose of bevacizumab in pretreated advanced stage EOC.

METHODS

We treated 15 patients, mostly with platinum resistant EOC, who had received a median of four prior cytotoxic regimens, with bevacizumab 5-7.5 mg/kg q21 days in combination with either carboplatin (n = 8), oral cyclofosfamide (n = 5) or weekly paclitaxel (n = 2). Bevacizumab was administered until disease progression. Tumor response was assessed by CA125 and fusion 18 F-FDG PET/contrast enhanced CT.

RESULTS

The median number of bevacizumab cycles was 21 (range 3-59). The median baseline CA125 was 272 U/ml and decreased to 15.2 U/ml at nadir. Tumor response was 4 complete response (CR) (26.7%) and 7 partial response (PR) (46.7%) by chemotherapy (CT), with an overall response rate of 73.4% (95% CI, 51.0 - 95.8) according to Response Evaluation Criteria In Solid Tumors (RECIST), and 6 CR (40%) and 4 PR (26.7%) by PET, for an overall metabolic response rate of 67% (95%CI, 42.8 - 90.6) according to PET Response Criteria in Solid Tumors (PERCIST). Median progression free survival (PFS) was 21 months and median overall survival (OS) was 24 months. Grade 3 adverse events related to bevacizumab were hypertension (n = 2), proteinuria (n = 1) and epistaxis (n = 5). Treatment was delayed in five patients for nasal bleeding or uncontrolled hypertension.

CONCLUSIONS

Low-dose bevacizumab and chemotherapy was well tolerated and active in a heavily pretreated population of advanced EOC. Further studies should assess the activity of low dose bevacizumab in EOC.

Role of FDG PET-CT in detecting recurrence in patients with uterine sarcoma: comparison with conventional imaging

PURPOSE

The purpose of the present study was to evaluate the role of 18F-fluorodeoxyglucose (FDG) PET-CT in detecting recurrent disease in posttherapy patients of uterine sarcoma and compare the same with conventional imaging (CI).

METHODS

A total of 15 FDG PET-CT studies were acquired in 12 posttherapy uterine sarcoma patients. The images were evaluated by two experienced nuclear medicine physicians in consensus. Clinical/imaging follow-up (minimum 6 months) and histopathology were taken as the reference standard. All the patients had also undergone CI (CT or MRI or ultrasonography) of the chest, abdomen, and pelvis. The diagnostic accuracy of FDG PET-CT was calculated and compared with that of CI.

RESULTS

The median age of the patients was 51.5 years (interquartile range: 47.5-53). Histopathology was leiomyosarcoma in six, carcinosarcoma in five, and endometrial stromal sarcoma in one patient. Six FDG PET-CT studies were carried out for suspected recurrence and nine for posttherapy surveillance. Six FDG PET-CTs were positive and nine were negative for recurrence. The sensitivity, specificity, and accuracy of FDG PET-CT were 85.7, 100, and 93.3%, respectively, on per study-based analysis, and 80, 100, and 83.3% on per lesion-based analysis. PET-CT showed higher sensitivity and specificity compared with CI for both study-based and lesion-based analysis. However, no significant difference was found between FDG PET-CT and CI either in the study-based or in the lesion-based analysis (P not significant).

CONCLUSION

FDG PET-CT is a highly sensitive and specific modality for detecting recurrence in posttherapy patients with uterine sarcoma. However, it provides no significant advantage over CI for this purpose.

PET/CT imaging in gynecologic malignancies: a critical overview of its clinical impact and our retrospective single center analysis

Gynecologic cancers represent a major global healthcare problem since they are associated with a significant mortality and morbidity. Over the last decade, considerable efforts have been spent in the development and optimization of novel diagnostic modalities to achieve an early diagnosis, aid in choosing appropriate treatment, improving long term surveillance, with the ultimate goal of increasing survival of gynecologic cancer patients. A growing body of evidence defines PET/CT as one of the most powerful tools for tumor, nodal and metastasis (TNM) cancer staging both in pre-treatment and in post treatment follow-up settings. At any phase of cancer evaluation, detection of metastasis represents one of the most critical impediments to the cure of tumor; traditional diagnostic imaging modalities, such as computed tomography (CT), are frequently found to inadequately stage the tumor, based on subsequent outcomes. As a consequence, patients may undergo pointless surgery for disease that could be treated with local medical therapies. In the setting of restaging, the ability to describe primary lesion, lymph nodes, possible metastases to peritoneum, bone, liver, lungs and brain renders PET/CT a potential alternative for a series of tests, including bone scanning, MRI or ultrasound, diagnostic CT, lymph node surgical sampling, that need to be used in combination in order to obtain a level of clinical confidence. In this review, we describe, the theoretical advantage and prognostic implications of PET/CT in the management of gynecologic cancer patients.

[FDG-PET and endometrial cancer]

FDG-PET is widely used for the diagnosis, the staging and the search for recurrence of many tumors. However, there are currently no recommendations for its use in endometrial cancer. This article is an update of the literature data to enable everyone to form an opinion on the subject. Future prospects are considered.

Advancements in the use of blood tests for cancer screening in women at high risk for endometrial and breast cancer

Several years ago, it was argued that the identification of serum biomarkers is one of the most promising approaches for the detection of early-stage malignant or even premalignant lesions. In this review, the need to establish better monitoring protocols is described for obese women who are at higher risk for the development of malignancies commonly associated with excess weight; specifically endometrial and postmenopausal breast cancer. These cancers have been chosen for this review article as our aim was to focus on female cancers that have been linked with obesity. Cancer screening is essential in detecting disease in its earliest stage in order to reduce morbidity and mortality; however, effective screening is not available for many cancer types. Even for cancers that have effective screening protocols available, there are barriers to screening in obese individuals, such as reduced mobility and embarrassment. These barriers often delay screening in these vulnerable population groups, leading to detection of the disease at a more advanced stage and ultimately leading to a poorer prognosis. As of today, biomarkers do not replace but augment imaging and other existing screening approaches. Future development of blood- or urine-based biomarkers as a way to screen individuals at high risk for certain cancers may prove to be an excellent method for overcoming the barriers that individuals at high risk are facing today. The overall purpose of this manuscript is to provide an overview of screening techniques and to identified barriers and alternate biomarker-based approaches for improvement of endometrial and breast cancer screening in obese women.

The value of FDG-PET/CT in the post-treatment evaluation of endometrial carcinoma: a comparison of PET/CT findings with conventional imaging and CA 125 as a tumour marker

OBJECTIVES

This retrospective study was designed to assess the value of positron emission tomography/computed tomography imaging (PET/CT) in the post-treatment evaluation of the patients with endometrial carcinoma and to compare PET/CT scan with conventional imaging (CI) including computed tomography (CT), ultrasonography (US) and magnetic resonance imaging (MRI) and CA 125 with both 20U/ml and 35U/ml cut-off values.

MATERIALS AND METHODS

A total of 31 patients who were treated for histopathologically proven endometrial adenocarcinoma, underwent PET/CT examination for restaging and suspected recurrence. Thirty five PET/CT studies were performed in 31 patients. Lesion status was determined on the basis of clinical follow-up including radiological imaging (follow-up CT scan) at least 6 months and response to therapy.

RESULTS

Of the 35 PET/CT studies, 13 (37%) studies were positive, whereas 22 (63%) of them were negative. On study-based analysis the overall sensitivity, specificity, accuracy for PET/CT imaging were 100%, 96% and 97%, respectively. The corresponding information for CI were 46%, 87% and 74%, for CA 125 (cut off=20U/ml) measurement were 45%, 88% and 74%, and for CA 125 (cut off=35U/ml) measurement were 27%, 100% and 78%, respectively. On lesion-based analysis, PET/CT revealed only one false positive case. In none of 21 patients with negative 22 PET/CT studies, no subsequent clinical or radiological recurrences were observed with a follow-up of at least 6 months.

CONCLUSION

FDG-PET/CT is found more useful modality than CI and CA 125 in the evaluation of post-treatment endometrial carcinoma patients, for suspected recurrence.

PET/CT in gynecologic cancer: present applications and future prospects--a clinician's perspective

This article briefly reviews the epidemiology, diagnosis, and treatment of the common gynecologic malignancies, with an emphasis on the shortcomings of current clinical practice. The persistent need to achieve early diagnosis, adjust proper treatment, enhance surveillance, and improve the outcome of these patients has led to the development of new diagnostic modalities. Novel tools such as 18F-fluorodeoxyglucose PET/CT should aim at enhancing the clinician's ability to make critical decisions in treating difficult scenarios.

Additional value of integrated PET/CT over PET alone in the initial staging and follow up of head and neck malignancy

OBJECTIVE

Clinical application of FDG-PET in head and neck cancer includes identification of metastases, unknown primary head and neck malignancy, or second primary carcinoma, and also recurrent tumor after treatment. In this study, the additional value of PET/CT fusion images over PET images alone was evaluated in patients with initial staging and follow up of head and neck malignancy.

METHODS

Forty patients with suspected primary head and neck malignancy and 129 patients with suspected relapse after treatment of head and neck malignancy were included. FDG-PET/CT study was performed after the intravenous administration of FDG (5 MBq/kg). Target of evaluation was set at primary tumor, cervical lymph node, and whole body. PET images and PET with CT fusion images were compared. Sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV) were calculated. Results of PET and PET/CT were compared with postoperative histopathological examination, and case by case comparison of PET and PET/CT results for each region was performed. The additional value of CT images over PET only images was assessed. Statistical differences in sensitivity and specificity were evaluated.

RESULTS

In the comparative evaluation of 507 targets by PET alone and PET/CT, 401 targets showed agreement of the results. Of the 106 discordant targets, 103 showed a positive result on PET alone and negative result on PET/CT. These results showed a significant difference (p< 0.01). Sensitivity of PET/CT was slightly higher than that of PET without statistical significance, while specificity of PET/CT was significantly higher than that of PET alone (Initial staging: 90.5% vs. 62.2%, p < 0.01; Follow up: 97.2% vs. 74.4%, p < 0.01). In Fisher's direct probability test, a significant difference was noted in the sensitivity (Initial staging: 91.3% vs. 87.0%, p < 0.01; Follow up: 93.9% vs. 91.4%, p <0.01).

CONCLUSIONS

Combined PET/CT showed improved diagnostic performance than PET alone by decreasing the number of false positive findings in patients with initial staging and follow up of head and neck malignancy.

Efficacy of 18F-FDG PET/CT in the evaluation of patients with recurrent cervical carcinoma

PURPOSE

Only a limited number of studies have evaluated the efficacy of 18F-FDG PET/CT for recurrent cervical carcinoma, which this study seeks to expand upon.

METHODS

This is a retrospective study of 30 women with cervical carcinoma who had a surveillance PET/CT after initial therapy. Sensitivity, specificity, accuracy, positive predictive value, and negative predictive value were calculated using a 2 × 2 contingency table with pathology results (76%) or clinical follow-up (24%) as the gold standard. The Wilson score method was used to perform 95% confidence interval estimations.

RESULTS

The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of PET/CT for the detection of local recurrence at the primary site were 93, 93, 93, 86, and 96%, respectively. The same values for the detection of distant metastases were 96, 95, 95, 96, and 95%, respectively. Seventy-one percent of the scans performed in symptomatic patients showed true-positive findings. In comparison, 44% of scans performed in asymptomatic patients showed true-positive findings. But, all patients subsequently had a change in their management based on the PET/CT findings such that the effect was notable. The maximum standardized uptake value ranged from 5 to 28 (average: 13 ± 7) in the primary site and 3 to 23 (average: 8 ± 4) in metastases which were significantly different (p = 0.04).

CONCLUSION

This study demonstrates favorable efficacy of 18F-FDG PET/CT for identification of residual/recurrent cervical cancer, as well as for localization of distant metastases.