Comparison of 18F-FDG PET/MRI and MRI for pre-therapeutic tumor staging of patients with primary cancer of the uterine cervix

Primary staging with 2[18F]-FDG-PET/CT and -PET/MRI and radiotherapy response evaluation with MRI in uterine cervical cancer: an interim analysis of a prospective clinical trial

BACKGROUND

In uterine cervical cancer (UCC), tumour staging is performed according to the 2018 International Federation of Gynecology and Obstetrics (FIGO) system, where imaging is incorporated, or the more generic Tumour Node Metastasis (TNM) classification. With the technical development in diagnostic imaging, continuous prospective evaluation of the different imaging methods contributing to stage determination is warranted. The aims of this interim study were to (1) evaluate the performance of radiological FIGO (rFIGO) and T staging (rT) with 2-fluorine-18-fluoro-deoxy-glucose (2[18F]-FDG)-positron emission tomography with computed tomography (PET/CT) and with magnetic resonance imaging (PET/MRI), compared to clinical FIGO (cFIGO) and T (cT) staging based on clinical examination and conventional imaging, in treatment-naïve UCC, and to (2) identify possible MRI biomarkers for early treatment response after radiotherapy.

METHODS

Ten consecutive patients with newly diagnosed UCC from the prospective PRODIGYN (Prognostic and Diagnostic Added Value of Medical Imaging in Staging and Treatment Planning of Gynecological Cancer) study (ethical approval number 2022-04207-01; NCT05855941) were included. Study participants underwent 2[18F]FDG-PET/CT and -PET/MRI, and an additional MRI one week after radiotherapy. Agreement between rFIGO and cFIGO was analysed using Cohen's kappa. Differences in rFIGO between 2[18F]FDG-PET/CT and -PET/MRI were evaluated with Wilcoxon signed ranks test, and added value of rFIGO for metastasis assessment was demonstrated with descriptive statistics.

RESULTS

In 2/10 patients, a higher stage was obtained with rFIGO compared to cFIGO, where presence of metastases led to upstaging. In 3/10, rFIGO was lower than cFIGO, and in 5/10 rFIGO and cFIGO were similar. Degree of agreement between rFIGO and cFIGO was poor, (κ = 0.091, p < 0.005) with 2[18F]FDG-PET/CT and (κ = - 0.010, p > 0.05) with FDG/PET/MRI). There was no significant difference between 2[18F]FDG-PET/CT and -PET/MRI for rFIGO (p = 0.18), or rT stage assessment (p = 0.32). MRI-derived tumour volume and apparent diffusion coefficient (ADC) were most affected on MRI one week after radiotherapy.

CONCLUSIONS

Our results indicate that there is an added value of rFIGO staging with 2[18F]FDG-PET/CT and -PET/MRI compared to clinical examination and conventional radiology, for metastasis assessment in treatment-naïve UCC. In early treatment response evaluation with MRI, ADC and tumour volume may be predictive parameters of interest in future prognostic analyses.

TRIAL REGISTRATION

Clinical Trials, NCT05855941. Registered 02 May 2023, https://clinicaltrials.gov/study/NCT05855941?term=NCT05855941&rank=1 .

Cervical cancer: a new era

Cervical cancer is a major global health issue, ranking as the fourth most common cancer in women worldwide. Depending on stage, histology, and patient factors, the standard management of cervical cancer is a combination of treatment approaches, including (fertility- or non-fertility-sparing) surgery, radiotherapy, platinum-based chemotherapy, and novel systemic therapies such as bevacizumab, immune checkpoint inhibitors, and antibody-drug conjugates. While ambitious global initiatives seek to eliminate cervical cancer as a public health problem, the management of cervical cancer continues to evolve with major advances in imaging modalities, surgical approaches, identification of histopathological risk factors, radiotherapy techniques, and biomarker-driven personalized therapies. In particular, the introduction of immune checkpoint inhibitors has dramatically altered the treatment of cervical cancer, leading to significant survival benefits in both locally advanced and metastatic/recurrent settings. As the landscape of cervical cancer therapies continues to evolve, the aim of the present review is to provide a comprehensive discussion of the current state and the latest practice-changing updates in cervical cancer.

The Added Role of Diffusion-Weighted Magnetic Resonance Imaging in Staging Uterine Cervical Cancer

BACKGROUND

Cervical cancer is considered one of the most common gynecological malignancies with an increased incidence in developing countries. Magnetic resonance imaging (MRI) plays a valuable role in staging cervical cancer and providing valuable information necessary for selecting the appropriate treatment plan, while closely correlating with the prognosis of the patient.

OBJECTIVE

The aim of this study is to assess the diagnostic value of diffusion-weighted imaging (DWI) in the preoperative loco-regional staging of cervical carcinoma. Our purpose is to establish apparent diffusion coefficient (ADC) values of cervical carcinoma compared with normal cervical tissue and their variability based on different pathological characteristics of the lesions.

MATERIAL AND METHODS

It is a retrospective analysis of 57 patients diagnosed with cervical cancer, who underwent MRI examinations. The study evaluated the aspect of the lesions on T2-weighted imaging, DWI, ADC maps, and pre- and post-contrast T1-weighted imaging with fat saturation.

RESULTS

The ADC mean values ranged between 0.63 × 10-3 mm2/second and 0.99 × 10-3 mm2/second (mean 0.79) for tumoral tissue and 1.33 × 10-3 mm2/second and 1.74 × 10-3 mm2/second (mean 1.59) for surrounding non-affected cervical tissue. The ADC mapping showed a decreasing trend with the increased sizes of the tumors (p<0.001). The ADC mean showed lower values with increased International Federation of Gynecology and Obstetrics (FIGO) stage of the tumors. The ADC mean value for cases that had spread to other organs (IVA+IVB) was significantly lower than that of the early stages (IB1 + IB2 + IIA2), stage IIB, and stages IIIA+IIIC1+IIIC2 (p<0.001). The ADC mean value of stage III disease was significantly lower than that of stage IIB, respectively early stages (p<0.001). The ADC mean value of the stage IIB tumor was significantly lower than that of the early stages (p<0.001). The differences in ADC mean values based on the histopathological type and differentiation grade were not statistically significant. The ADC mean value of the cases with positive pelvic lymph nodes was significantly lower than in those with negative lymph nodes (p<0.001).

CONCLUSION

ADC mean values of cervical carcinoma are significantly lower than those from unaffected uterine tissue and they also correlate with the severity of the disease. The advancements and additional capabilities DWI can bring are the elements of interest in this article. Using DWI means a more accurate capability in diagnosing cervical cancer, providing a compelling argument for its integration into standard clinical practice. This study discusses the quantitative imaging parameters of DWI such as ADC values, which can provide objective measurements for tumor evaluation. These parameters can be standardized and used across different institutions, enhancing the reproducibility and reliability of imaging findings.

Current Applications of PET/MR: Part II: Clinical Applications II

Due to the major improvements in the hardware and image reconstruction algorithms, positron emission tomography/magnetic resonance imaging (PET/MR) is now a reliable state-of-the-art hybrid modality in medical practice. Currently, it can provide a broad range of advantages in preclinical and clinical imaging compared to single-modality imaging. In the second part of this review, we discussed the further clinical applications of PET/MR. In the chest, PET/MR has particular potential in the oncology setting, especially when utilizing ultrashort/zero echo time MR sequences. Furthermore, cardiac PET/MR can provide reliable information in evaluating myocardial inflammation, cardiac amyloidosis, myocardial perfusion, myocardial viability, atherosclerotic plaque, and cardiac masses. In gastrointestinal and hepato-pancreato-biliary malignancies, PET/MR is able to precisely detect metastases to the liver, being superior over the other imaging modalities. In genitourinary and gynaecology applications, PET/MR is a comprehensive diagnostic method, especially in prostate, endometrial, and cervical cancers. Its simultaneous acquisition has been shown to outperform other imaging techniques for the detection of pelvic nodal metastases and is also a reliable modality in radiation planning. Lastly, in haematologic malignancies, PET/MR can significantly enhance lymphoma diagnosis, particularly in detecting extra-nodal involvement. It can also comprehensively assess treatment-induced changes. Furthermore, PET/MR may soon become a routine in multiple myeloma management, being a one-stop shop for evaluating bone, bone marrow, and soft tissues.

Precision matters: the value of PET/CT and PET/MRI in the clinical management of cervical cancer

The incidence of cervical cancer has been increasing recently, becoming an essential factor threatening patients' health. Positron emission computed tomography (PET/CT) and positron emission tomography/magnetic resonance imaging (PET/MRI) are multimodal molecular imaging methods that combine functional imaging (PET) and anatomical imaging (CT) with MRI fusion technology. They play an important role in the clinical management of patients with cervical cancer. Precision radiotherapy refers to the use of advanced intensive modulated radiotherapy (IMRT) to give different doses of radiation to different treatment areas to achieve the purpose of killing tumors and protecting normal tissues to the greatest extent. At present, pelvic target delineation is mostly based on CT and MRI, but these mostly provide anatomical morphological information, which is difficult to show the internal metabolism of tumors. PET/CT and PET/MRI combine information on biological function, metabolism and anatomical structure, thereby more accurately distinguishing the boundaries between tumor and non-tumor tissues and playing a positive guiding role in improving radiotherapy planning (RTP) for cervical cancer and evaluating treatment effect.

ACR Appropriateness Criteria® Pretreatment Evaluation and Follow-Up of Invasive Cancer of the Cervix: 2023 Update

Cervical cancer is a common gynecological malignancy worldwide. Cervical cancer is staged based on the International Federation of Gynecology and Obstetrics (FIGO) classification system, which was revised in 2018 to incorporate radiologic and pathologic data. Imaging plays an important role in pretreatment assessment including initial staging and treatment response assessment of cervical cancer. Accurate determination of tumor size, local extension, and nodal and distant metastases is important for treatment selection and for prognostication. Although local recurrence can be diagnosed by physical examination, imaging plays a critical role in detection and follow-up of local and distant recurrence and subsequent treatment selection. 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 process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

The Role of Imaging in Cervical Cancer Staging: ESGO/ESTRO/ESP Guidelines (Update 2023)

Following the European Society of Gynaecological Oncology (ESGO), the European Society for Radiotherapy and Oncology (ESTRO), and the European Society of Pathology (ESP) joint guidelines (2018) for the management of patients with cervical cancer, treatment decisions should be guided by modern imaging techniques. After five years (2023), an update of the ESGO-ESTRO-ESP recommendations was performed, further confirming this statement. Transvaginal/transrectal ultrasound (TRS/TVS) or pelvic magnetic resonance (MRI) enables tumor delineation and precise assessment of its local extent, including the evaluation of the depth of infiltration in the bladder- or rectal wall. Additionally, both techniques have very high specificity to confirm the presence of metastatic pelvic lymph nodes but fail to exclude them due to insufficient sensitivity to detect small-volume metastases, as in any other currently available imaging modality. In early-stage disease (T1a to T2a1, except T1b3) with negative lymph nodes on TVS/TRS or MRI, surgicopathological staging should be performed. In all other situations, contrast-enhanced computed tomography (CECT) or 18F-fluorodeoxyglucose positron emission tomography combined with CT (PET-CT) is recommended to assess extrapelvic spread. This paper aims to review the evidence supporting the implementation of diagnostic imaging with a focus on ultrasound at primary diagnostic workup of cervical cancer.

Diagnostic performance of whole-body [18F]FDG PET/MR in cancer M staging: A systematic review and meta-analysis

OBJECTIVES

To calculate the pooled diagnostic performances of whole-body [18F]FDG PET/MR in M staging of [18F]FDG-avid cancer entities.

METHODS

A diagnostic meta-analysis was conducted on the [18F]FDG PET/MR in M staging, including studies: (1) evaluated [18F]FDG PET/MR in detecting distant metastasis; (2) compared[ 18F]FDG PET/MR with histopathology, follow-up, or asynchronous multimodality imaging as the reference standard; (3) provided data for the whole-body evaluation; (4) provided adequate data to calculate the meta-analytic performances. Pooled performances were calculated with their confidence interval. In addition, forest plots, SROC curves, and likelihood ratio scatterplots were drawn. All analyses were performed using STATA 16.

RESULTS

From 52 eligible studies, 2289 patients and 2072 metastases were entered in the meta-analysis. The whole-body pooled sensitivities were 0.95 (95%CI: 0.91-0.97) and 0.97 (95%CI: 0.91-0.99) at the patient and lesion levels, respectively. The pooled specificities were 0.99 (95%CI: 0.97-1.00) and 0.97 (95%CI: 0.90-0.99), respectively. Additionally, subgroup analyses were performed. The calculated pooled sensitivities for lung, gastrointestinal, breast, and gynecological cancers were 0.90, 0.93, 1.00, and 0.97, respectively. The pooled specificities were 1.00, 0.98, 0.97, and 1.00, respectively. Furthermore, the pooled sensitivities for non-small cell lung, colorectal, and cervical cancers were 0.92, 0.96, and 0.86, respectively. The pooled specificities were 1.00, 0.95, and 1.00, respectively.

CONCLUSION

[18F]FDG PET/MR was a highly accurate modality in M staging in the reported [18F]FDG-avid malignancies. The results showed high sensitivity and specificity in each reviewed malignancy type. Thus, our findings may help clinicians and patients to be confident about the performance of [18F]FDG PET/MR in the clinic.

CLINICAL RELEVANCE STATEMENT

Although [18F]FDG PET/MR is not a routine imaging technique in current guidelines, mostly due to its availability and logistic issues, our findings might add to the limited evidence regarding its performance, showing a sensitivity of 0.95 and specificity of 0.97.

KEY POINTS

• The whole-body [18F]FDG PET/MR showed high accuracy in detecting distant metastases at both patient and lesion levels. • The pooled sensitivities were 95% and 97% and pooled specificities were 99% and 97% at patient and lesion levels, respectively. • The results suggested that 18F-FDG PET/MR was a strong modality in the exclusion and confirmation of distant metastases.

Enhancing the Accuracy of Lymph-Node-Metastasis Prediction in Gynecologic Malignancies Using Multimodal Federated Learning: Integrating CT, MRI, and PET/CT

Gynecological malignancies, particularly lymph node metastasis, have presented a diagnostic challenge, even with traditional imaging techniques such as CT, MRI, and PET/CT. This study was conceived to explore and, subsequently, to bridge this diagnostic gap through a more holistic and innovative approach. By developing a comprehensive framework that integrates both non-image data and detailed MRI image analyses, this study harnessed the capabilities of a multimodal federated-learning model. Employing a composite neural network within a federated-learning environment, this study adeptly merged diverse data sources to enhance prediction accuracy. This was further complemented by a sophisticated deep convolutional neural network with an enhanced U-NET architecture for meticulous MRI image processing. Traditional imaging yielded sensitivities ranging from 32.63% to 57.69%. In contrast, the federated-learning model, without incorporating image data, achieved an impressive sensitivity of approximately 0.9231, which soared to 0.9412 with the integration of MRI data. Such advancements underscore the significant potential of this approach, suggesting that federated learning, especially when combined with MRI assessment data, can revolutionize lymph-node-metastasis detection in gynecological malignancies. This paves the way for more precise patient care, potentially transforming the current diagnostic paradigm and resulting in improved patient outcomes.

Prognostic value of 18F-FDG PET in uterine cervical cancer patients with stage IIICr allocated by imaging

The effect on survival of radiographic lymph node metastasis in uterine cervical cancer patients is more important than before, even though its prognostic value not been well investigated. The aim of our study is to evaluate the prognostic potential of 18F-fluorodeoxyglucose Positron Emission Tomography (18F-FDG PET) compared with Computed Tomography (CT) in uterine cervical cancer patients with stage IIICr allocated by imaging. Fifty-five patients with biopsy-proven primary cervical cancer underwent definitive radiation therapy for stages IIB-IVB of The International Federation of Gynecology and Obstetrics (FIGO) 2018 classifications. The prognostic performance of pretreatment 18F-FDG PET and CT for assessing lymph node metastasis was evaluated by two experienced readers. The PET and CT findings were correlated with the risk of progression-free survival (PFS) and overall survival (OS). Kaplan-Meier survival curves showed that PFS was significantly worse in patients with positive lymph nodes on 18F-FDG PET than in those patients with negative lymph nodes on 18F-FDG PET (p = 0.003), whereas there was no significant difference in PFS between patients with lymph nodes sized ≥ 1 cm and those sized < 1 cm (p = 0.140). Univariate analysis showed that positive lymph nodes on 18F-FDG PET was significantly associated with poor PFS (p = 0.006), whereas lymph node size was not significantly associated with poor PFS (p = 0.145). In multivariate analysis, positive lymph nodes on 18F-FDG PET was significantly associated with poor PFS (p = 0.006) and was an independent prognostic factor for PFS. 18F-FDG PET offers high prognostic value for patients with stage IIICr allocated by imaging compared with CT, suggesting that 18F-FDG PET might be useful in clinical staging decisions and thus promote optimal diagnostic and therapeutic strategies.

18F-FDG PET/MRI and 18F-FDG PET/CT for the Management of Gynecological Malignancies: A Comprehensive Review of the Literature

OBJECTIVE

Positron emission tomography with 2-deoxy-2-[fluorine-18] fluoro- D-glucose integrated with computed tomography (18F-FDG PET/CT) or magnetic resonance imaging (18F-FDG PET/MRI) has emerged as a promising tool for managing various types of cancer. This review study was conducted to investigate the role of 18F- FDG PET/CT and FDG PET/MRI in the management of gynecological malignancies.

SEARCH STRATEGY

We searched for relevant articles in the three databases PubMed/MEDLINE, Scopus, and Web of Science.

SELECTION CRITERIA

All studies reporting data on the FDG PET/CT and FDG PET MRI in the management of gynecological cancer, performed anywhere in the world and published exclusively in the English language, were included in the present study.

DATA COLLECTION AND ANALYSIS

We used the EndNote software (EndNote X8.1, Thomson Reuters) to list the studies and screen them on the basis of the inclusion criteria. Data, including first author, publication year, sample size, clinical application, imaging type, and main result, were extracted and tabulated in Excel. The sensitivity, specificity, and diagnostic accuracy of the modalities were extracted and summarized.

MAIN RESULTS

After screening 988 records, 166 studies published between 2004 and 2022 were included, covering various methodologies. Studies were divided into the following five categories: the role of FDG PET/CT and FDG-PET/MRI in the management of: (a) endometrial cancer (n = 30); (b) ovarian cancer (n = 60); (c) cervical cancer (n = 50); (d) vulvar and vagina cancers (n = 12); and (e) gynecological cancers (n = 14).

CONCLUSIONS

FDG PET/CT and FDG PET/MRI have demonstrated potential as non-invasive imaging tools for enhancing the management of gynecological malignancies. Nevertheless, certain associated challenges warrant attention.

Added Value of FDG PET/MRI in Gynecologic Oncology: A Pictorial Review

Fluorine 18-fluorodeoxyglucose (FDG) PET and MRI independently play a valuable role in the management of patients with gynecologic malignancies, particularly endometrial and cervical cancer. The PET/MRI hybrid imaging technique combines the metabolic information obtained from PET with the excellent soft-tissue resolution and anatomic details provided by MRI in a single examination. MRI is the modality of choice for assessment of local tumor extent in the pelvis, whereas PET is used to assess for local-regional spread and distant metastases. The authors discuss the added value of FDG PET/MRI in imaging gynecologic malignancies of the pelvis, with a focus on the role of FDG PET/MRI in diagnosis, staging, assessing treatment response, and characterizing complications. PET/MRI allows better localization and demarcation of the extent of disease, characterization of lesions and involvement of adjacent organs and lymph nodes, and improved differentiation of benign from malignant tissues, as well as detection of the presence of distant metastasis. It also has the advantages of decreased radiation dose and a higher signal-to-noise ratio of a prolonged PET examination of the pelvis contemporaneous with MRI. The authors provide a brief technical overview of PET/MRI, highlight how simultaneously performed PET/MRI can improve stand-alone MRI and PET/CT in gynecologic malignancies, provide an image-rich review to illustrate practical and clinically relevant applications of this imaging technique, and review common pitfalls encountered in clinical practice. ©RSNA, 2023 Quiz questions for this article are available in the supplemental material.

PET/MRI in Gynecologic Malignancy

Patients with gynecologic malignancies often require a multimodality imaging approach for initial staging, treatment response assessment, and surveillance. MRI imaging and PET are two well-established and widely accepted modalities in this setting. Although PET and MRI imaging are often acquired separately on two platforms (a PET/computed tomography [CT] and an MRI imaging scanner), hybrid PET/MRI scanners offer the potential for comprehensive disease assessment in one visit. Gynecologic malignancies have been one of the most successful areas for implementation of PET/MRI. This article provides an overview of the role of this platform in the care of patients with gynecologic malignancies.

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.

Post treatment imaging in patients with local advanced cervical carcinoma

Cervical cancer (CC) is the fourth leading cause of death in women worldwide and despite the introduction of screening programs about 30% of patients presents advanced disease at diagnosis and 30-50% of them relapse in the first 5-years after treatment. According to FIGO staging system 2018, stage IB3-IVA are classified as locally advanced cervical cancer (LACC); its correct therapeutic choice remains still controversial and includes neoadjuvant chemo-radiotherapy, external beam radiotherapy, brachytherapy, hysterectomy or a combination of these modalities. In this review we focus on the most appropriated therapeutic options for LACC and imaging protocols used for its correct follow-up. We explore the imaging findings after radiotherapy and surgery and discuss the role of imaging in evaluating the response rate to treatment, selecting patients for salvage surgery and evaluating recurrence of disease. We also introduce and evaluate the advances of the emerging imaging techniques mainly represented by spectroscopy, PET-MRI, and radiomics which have improved diagnostic accuracy and are approaching to future direction.

Multiparametric Dual-Time-Point [18F]FDG PET/MRI for Lymph Node Staging in Patients with Untreated FIGO I/II Cervical Carcinoma

[¹⁸F]FDG PET/MRI was shown to have limited sensitivity for N-staging in FIGO I/II cervical carcinoma. Therefore, this prospective study aimed to investigate the additional value of multiparametric dual-time-point PET/MRI and to assess potential influencing factors for lymph node metastasis (LNM) detection. A total of 63 patients underwent whole-body dual-time-point [¹⁸F]FDG PET/MRI 60 + 90 min p.i., and 251 LN were evaluated visually, quantified multiparametrically, and correlated with histology. Grading of the primary tumor (G2/G3) had a significant impact on visual detection (sens: 8.3%/31%). The best single parameter for LNM detection was SUVavg, however, with a significant loss of discriminatory power in G2 vs. G3 tumors (AUC: 0.673/0.901). The independent predictors SUVavg, ∆SUVpeak, LN sphericity, ADC, and histologic grade were included in the logistic-regression-based malignancy score (MS) for multiparametric analysis. Application of MS enhanced AUCs, especially in G2 tumors (AUC: G2:0.769; G3:0.877) and improved the accuracy for single LNM from 34.5% to 55.5% compared with the best univariate parameter SUVavg. Compared with visual analysis, the use of the malignancy score increased the overall sensitivity from 31.0% to 79.3% (Youden optimum) with a moderate decrease in specificity from 98.3% to 75.6%. These findings indicate that multiparametric evaluation of dual-time-point PET/MRI has the potential to improve accuracy compared with visual interpretation and enables sufficient N-staging also in G2 cervical carcinoma.

Application of a nomogram to radiomics labels in the treatment prediction scheme for lumbar disc herniation

Objective

To investigate and verify the efficiency and effectiveness of a nomogram based on radiomics labels in predicting the treatment of lumbar disc herniation (LDH).

Methods

By reviewing medical records that were analysed over the past three years, clinical and imaging data of 200 lumbar disc patients at the Affiliated Hospital of Jiangxi University of Traditional Chinese Medicine were obtained. The collected cases were randomly divided into a training group (n = 140) and a testing group (n = 60) at a ratio of 7:3. Two radiologists with experience in reading orthopaedics images independently segmented the ROIs. The whole intervertebral disc with the most obvious protrusion in the sagittal plane T2WI lumbar MRI as a mask (ROI) is sketched. The LASSO (Least Absolute Shrinkage And Selection Operator) algorithm was used to filter the features after extracting the radiomics features. The multivariate logistic regression model was used to construct a quantitative imaging Rad‑Score for the selected features with nonzero coefficients. The radiomics labels and nomogram were evaluated using the receiver operating characteristic curve (ROC) and the area under the curve (AUC). The calibration curve was used to evaluate the consistency between the nomogram prediction and the actual treatment plan. The DCA decision curve was used to evaluate the clinical applicability of the nomogram.

Result

Following feature extraction, 11 radiomics features were used to construct the radiomics label for predicting the treatment plan of LDH. A nomogram was then constructed. The AUC was 0.93 (95% CI: 0.90–0.97), with a sensitivity of 89%, a specificity of 91%, a positive predictive value of 92.7%, a negative predictive value of 89.4%, and an accuracy of 91%. The calibration curve showed that there was good consistency between the prediction and the actual observation. The DCA decision curve analysis showed that the nomogram of the imaging group has great potential for clinical application when the risk threshold is between 5 and 72%.

Conclusion

A nomogram based on radiomics labels has good predictive value for the treatment of LDH and can be used as a reference for clinical decision-making.

Advanced Tumor Imaging Approaches in Human Tumors

The management of cancer has always relied heavily on the imaging modalities used to detect and monitor it. While many of these modalities have been around for decades, the technology surrounding them is always improving, and much has been discovered in recent years about the nature of tumors because of this. There have been several areas that have aided those discoveries. The use of artificial intelligence has already helped immensely in the quality of images taken but has not yet been widely implemented in clinical settings. Molecular imaging has proven to be useful in diagnosing different types of cancers based on the specificity of the probes/contrast agents used. Intravital imaging has already uncovered new information regarding the heterogeneity of the tumor vasculature. These three areas have provided a lot of useful information for the diagnosis and treatment of cancer, but further research and development in human trials is necessary to allow these techniques to fully utilize the information obtained thus far.

A decade of multi-modality PET and MR imaging in abdominal oncology

OBJECTIVES

To investigate trends observed in a decade of published research on multimodality PET(/CT)+MR imaging in abdominal oncology, and to explore how these trends are reflected by the use of multimodality imaging performed at our institution.

METHODS

First, we performed a literature search (2009-2018) including all papers published on the multimodality combination of PET(/CT) and MRI in abdominal oncology. Retrieved papers were categorized according to a structured labelling system, including study design and outcome, cancer and lesion type under investigation and PET-tracer type. Results were analysed using descriptive statistics and evolutions over time were plotted graphically. Second, we performed a descriptive analysis of the numbers of MRI, PET/CT and multimodality PET/CT+MRI combinations (performed within a ≤14 days interval) performed during a similar time span at our institution.

RESULTS

Published research papers involving multimodality PET(/CT)+MRI combinations showed an impressive increase in numbers, both for retrospective combinations of PET/CT and MRI, as well as hybrid PET/MRI. Main areas of research included new PET-tracers, visual PET(/CT)+MRI assessment for staging, and (semi-)quantitative analysis of PET-parameters compared to or combined with MRI-parameters as predictive biomarkers. In line with literature, we also observed a vast increase in numbers of multimodality PET/CT+MRI imaging in our institutional data.

CONCLUSIONS

The tremendous increase in published literature on multimodality imaging, reflected by our institutional data, shows the continuously growing interest in comprehensive multivariable imaging evaluations to guide oncological practice.

ADVANCES IN KNOWLEDGE

The role of multimodality imaging in oncology is rapidly evolving. This paper summarizes the main applications and recent developments in multimodality imaging, with a specific focus on the combination of PET+MRI in abdominal oncology.

Lymph Node Staging with a Combined Protocol of 18F-FDG PET/MRI and Sentinel Node SPECT/CT: A Prospective Study in Patients with FIGO I/II Cervical Carcinoma

Lymph node metastasis (LNM) is present in a minority of patients with early stages of cervical carcinomas. As conventional imaging including PET/CT has shown limited sensitivity, systematic lymphadenectomies are often conducted for staging purposes. Therefore, the aim of this prospective study was to analyze the impact of 18F-FDG PET/MRI in addition to sentinel lymph node (SLN) biopsy on lymph node (LN) status. Methods: Forty-two women with an initial diagnosis of Fédération Internationale de Gynécologie et d'Obstétrique (FIGO) IA-IIB cervical carcinoma were included between March 2016 and April 2019. Each patient underwent preoperative whole-body 18F-FDG PET/MRI and SLN imaging with SPECT/CT after intracervical injection of 99mTc-labeled nanocolloid. Systematic lymphadenectomy and SLN biopsy served as the reference standard. Staging using PET/MRI was performed by nuclear medicine and radiology experts working in consensus. Results: One patient was excluded from surgical staging because of liver metastases newly diagnosed on PET/MRI. The overall prevalence of LNM in the remaining 41 patients was 29.3% (12/41). Five of 12 patients with LNM had solely small metastases with a maximum diameter of 5 mm. The consensus interpretation showed PET/MRI to have a specificity of 100% (29/29; 95% CI, 88.3%-100%) for LNM staging but a low sensitivity, 33.3% (4/12; 95% CI, 12.8%-60.9%). LN size was the most important factor for the detectability of metastases, since only LNMs larger than 5 mm could be identified by PET/MRI (sensitivity, 57.1% for >5 mm and 0% for ≤5 mm). Paraaortic LNM was evaluated accurately in 3 of the 4 patients with paraaortic LN metastasis. SLNs were detectable by SPECT/CT in 82.9% of the patients or 69.0% of the hemipelves. In cases with an undetectable SLN on SPECT/CT, the malignancy rate was considerably higher (31.2% vs. 19.3%). The combination of PET/MRI and SLN SPECT/CT improved the detection of pelvic LNM from 33.3% to 75%. Conclusion:18F-FDG PET/MRI is a highly specific N-staging method and improves LNM detection. Because of the limited sensitivity in frequently occurring small LNMs, PET/MRI should be combined with SLN mapping. The proposed combined protocol helps to decide whether extensive surgical staging is necessary in patients with FIGO I/II cervical cancer.

Definitive Chemoradiotherapy versus Radical Hysterectomy Followed by Tailored Adjuvant Therapy in Women with Early-Stage Cervical Cancer Presenting with Pelvic Lymph Node Metastasis on Pretreatment Evaluation: A Propensity Score Matching Analysis

Simple Summary

Pelvic nodal involvement is frequently present in early-stage cervical cancer patients on pretreatment imaging studies. However, it is unclear whether radical chemoradiotherapy (CRT) or radical hysterectomy RH followed by tailored adjuvant radiotherapy is more appropriate in these patients. We compared oncological outcomes of up-front surgery followed by tailored adjuvant radiotherapy and definitive CRT in these patients. We found no differences in outcomes existed between definitive CRT and hysterectomy with tailored adjuvant radiotherapy. However, after surgery, 88.7% of patients required adjuvant radiotherapy. These findings suggest that definitive CRT can avoid unplanned tri-modality therapy without compromising oncologic outcomes.

Abstract

To compare the oncologic outcomes between chemoradiotherapy (CRT) and radical hysterectomy followed by tailored adjuvant therapy in patients with early cervical cancer presenting with pelvic lymph node metastasis. We retrospectively analyzed the medical records of women with early cervical cancer presenting with positive pelvic nodes identified on pretreatment imaging assessment. Propensity score matching was employed to control for the heterogeneity between two groups according to confounding factors. Overall survival, disease-free survival, and pattern of failure were compared between the two groups. A total of 262 patients were identified; among them, 67 received definitive CRT (group A), and 195 received hysterectomy (group B). Adjuvant therapy was administered to 88.7% of group B. There were no significant differences between group A and group B regarding the 5-year overall survival rates (89.2% vs. 89.0%) as well as disease-free survival rates (80.6% vs. 82.7%), and patterns of failure. Distant metastasis was the major failure pattern identified in both groups. In multivariate analysis, non-squamous histology was significantly associated with poorer overall survival. As there are no significant differences in 5-year OS, DFS, and patterns of failure, definitive CRT could avoid the combined modality therapy without compromising oncologic outcomes.

Preoperative Prediction of Lymphovascular Space Invasion in Cervical Cancer With Radiomics -Based Nomogram

PURPOSE

To build and evaluate a radiomics-based nomogram that improves the predictive performance of the LVSI in cervical cancer non-invasively before the operation.

METHOD

This study involved 149 patients who underwent surgery with cervical cancer from February 2017 to October 2019. Radiomics features were extracted from T2 weighted imaging (T2WI). The radiomic features were selected by logistic regression with the least absolute shrinkage and selection operator (LASSO) penalty in the training cohort. Based on the selected features, support vector machine (SVM) algorithm was used to build the radiomics signature on the training cohort. Incorporating radiomics signature and clinical risk factors, the radiomics-based nomogram was developed. The sensitivity, specificity, accuracy, and area under the curve (AUC) and Receiver operating characteristic (ROC) curve were calculated to assess these models.

RESULT

The radiomics model performed much better than the clinical model in both training (AUCs 0.925 vs. 0.786, accuracies 87.5% vs. 70.5%, sensitivities 83.6% vs. 41.7% and specificities 90.9% vs. 94.7%) and testing (AUCs 0.911 vs. 0.706, accuracies 84.0% vs. 71.3%, sensitivities 81.1% vs. 43.4% and specificities 86.4% vs. 95.0%). The combined model based on the radiomics signature and tumor stage, tumor infiltration depth and tumor pathology yielded the best performance (training cohort, AUC = 0.943, accuracies 89.5%, sensitivities 85.4% and specificities 92.9%; testing cohort, AUC = 0.923, accuracies 84.6%, sensitivities 84.0% and specificities 85.1%).

CONCLUSION

Radiomics-based nomogram was a useful tool for predicting LVSI of cervical cancer. This would aid the selection of the optimal therapeutic strategy and clinical decision-making for individuals.

Diagnosis and staging of hepatobiliary malignancies: Potential incremental value of (18)F-FDG-PET/MRI compared to MRI of the liver

OBJECTIVE

 The purpose of the study was to investigate the potential added value of ¹⁸F-FDG-PET/MRI (functional information derived from PET) over standard diagnostic liver MRI (excellent soft tissue characterization) in diagnosing and staging suspected primary hepatobiliary malignancies including extrahepatic cholangiocarcinoma (ECC), intrahepatic cholangiocellular carcinoma (ICC) and gallbladder cancer (GBCA).

METHODS

 Twenty consecutive patients with suspected hepatobiliary malignancy were included in this retrospective study. All patients underwent combined whole-body (WB) ¹⁸F-FDG-PET/MRI including contrast-enhanced MRI of the liver, contrast-enhanced WB-MRI and WB ¹⁸F-FDG-PET. Two experienced readers staged hepatobiliary disease using TNM criteria: first based on MRI alone and then based on combined ¹⁸F-FDG-PET/MRI. Subsequently, the impact of FDG-PET/MRI on clinical management compared to MRI alone was recorded. Histopathologic proof served as the reference standard.

RESULTS

 Hepatobiliary neoplasms were present in 16/20 patients (ECC n = 3, ICC n = 8, GBCA n = 5), two patients revealed benign disease, two were excluded. TNM staging with ¹⁸F-FDG-PET/MRI was identical to MRI alone in 11/18 (61.1 %) patients and correctly changed the stage in 4/18 (22.2 %), resulting in a change in management for 2/4 patients (11.1 %). ¹⁸F-FDG-PET/MRI was false-positive in 3/18 cases (16.7 %). Both MRI and ¹⁸F-FDG-PET/MRI were falsely positive in 1 case without malignancy.

CONCLUSIONS

 A small incremental benefit of ¹⁸F-FDG-PET/MRI over standard MRI of the liver was observed. However, in some cases ¹⁸F-FDG-PET/MRI may lead to false-positive findings. Overall there is seemingly limited role of ¹⁸F-FDG-PET/MRI in patients with suspected hepatobiliary malignancy.

Staging, recurrence and follow-up of uterine cervical cancer using MRI: Updated Guidelines of the European Society of Urogenital Radiology after revised FIGO staging 2018

OBJECTIVES

The recommendations cover indications for MRI examination including acquisition planes, patient preparation, imaging protocol including multi-parametric approaches such as diffusion-weighted imaging (DWI-MR),  dynamic contrast-enhanced imaging (DCE-MR) and standardised reporting. The document also underscores the value of whole-body 18-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography (FDG-PET/CT) and highlights potential future methods.

METHODS

In 2019, the ESUR female pelvic imaging working group reviewed the revised 2018 FIGO staging system, the up-to-date clinical management guidelines, and the recent imaging literature. The RAND-UCLA Appropriateness Method (RAM) was followed to develop the current ESUR consensus guidelines following methodological steps: literature research, questionnaire developments, panel selection, survey, data extraction and analysis.

RESULTS

The updated ESUR guidelines are recommendations based on ≥ 80% consensus among experts. If ≥ 80% agreement was not reached, the action was indicated as optional.

CONCLUSIONS

The present ESUR guidelines focus on the main role of MRI in the initial staging, response monitoring and evaluation of disease recurrence. Whole-body FDG-PET plays an important role in the detection of lymph nodes (LNs) and distant metastases.

KEY POINTS

• T2WI and DWI-MR are now recommended for initial staging, monitoring of response and evaluation of recurrence. • DCE-MR is optional; its primary role remains in the research setting. • T2WI, DWI-MRI and whole-body FDG-PET/CT enable comprehensive assessment of treatment response and recurrence.

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.

Value of integrated PET-IVIM MRI in predicting lymphovascular space invasion in cervical cancer without lymphatic metastasis

PURPOSE

To evaluate the contributory value of positron emission tomography (PET)-intravoxel incoherent motion (IVIM) magnetic resonance imaging (MRI) in the prediction of lymphovascular space invasion (LVSI) in patients with cervical cancer without lymphatic metastasis.

MATERIALS AND METHODS

A total of 90 patients with cervical cancer without signs of lymph node metastasis on PET/MRI were enrolled in this study. The tumours were classified into LVSI-positive (n = 25) and LVSI-negative (n = 65) groups according to postoperative pathology. The PET-derived parameters (SUV_max, SUV_mean, metabolic tumour volume (MTV) and total lesion glycolysis (TLG)) and IVIM-derived parameters (ADC_mean, ADC_min, D_mean, D_min, f, D* and gross tumour volume (GTV)) between the two groups were evaluated using a Student's t test (Mann-Whitney U test for variables with a nonnormal distribution) and receiver operating characteristic (ROC) curves. The optimal combination of PET/MR parameters for predicting LVSI was investigated using univariate and multivariate logistic regression models and evaluated by ROC curves. The optimal cutoff threshold values corresponded to the maximal values of the Youden index. A control model was established using 1000 bootstrapped samples, for which the performance was validated using calibration curves and ROC curves.

RESULTS

PET-derived parameters (SUV_max, SUV_mean, MTV, TLG) and IVIM MRI-derived parameters (D_min, ADC_min, GTV) were significantly different between patients with and without LVSI (P < 0.05). Logistic analyses showed that a combination of TLG and D_min had the strongest predictive value for LVSI diagnosis (area under the curve (AUC), 0.861; sensitivity, 80.00; specificity, 86.15; P < 0.001). The optimal cutoff threshold values for D_min and TLG were 0.58 × 10^-3 mm²/s and 66.68 g/cm³, respectively. The verification model showed the combination of TLG and D_min had the strongest predictive value, and its ROC curve and calibration curve showed good accuracy (AUC, 0.878) and consistency.

CONCLUSIONS

The combination of TLG and D_min may be the best indicator for predicting LVSI in cervical cancer without lymphatic metastasis.

Diagnostic efficiency of whole-body 18F-FDG PET/MRI, MRI alone, and SUV and ADC values in staging of primary uterine cervical cancer

Background

The use of PET/MRI for gynecological cancers is emerging. The purpose of this study was to assess the additional diagnostic value of PET over MRI alone in local and whole-body staging of cervical cancer, and to evaluate the benefit of standardized uptake value (SUV) and apparent diffusion coefficient (ADC) in staging.

Methods

Patients with histopathologically-proven cervical cancer and whole-body ¹⁸F-FDG PET/MRI obtained before definitive treatment were retrospectively registered. Local tumor spread, nodal involvement, and distant metastases were evaluated using PET/MRI or MRI dataset alone. Histopathology or clinical consensus with follow-up imaging were used as reference standard. Tumor SUVmax and ADC were measured and SUVmax/ADC ratio calculated. Area under the curve (AUC) was determined to predict diagnostic performance and Mann-Whitney U test was applied for group comparisons.

Results

In total, 33 patients who underwent surgery (n = 23) or first-line chemoradiation (n = 10) were included. PET/MRI resulted in higher AUC compared with MRI alone in detecting parametrial (0.89 versus 0.73), vaginal (0.85 versus 0.74), and deep cervical stromal invasion (0.96 versus 0.74), respectively. PET/MRI had higher diagnostic confidence than MRI in identifying patients with radical cone biopsy and no residual at hysterectomy (sensitivity 89% versus 44%). PET/MRI and MRI showed equal AUC for pelvic nodal staging (both 0.73), whereas AUC for distant metastases was higher using PET/MRI (0.80 versus 0.67). Tumor SUVmax/ADC ratio, but not SUVmax or ADC alone, was significantly higher in the presence of metastatic pelvic lymph nodes (P < 0.05).

Conclusions

PET/MRI shows higher accuracy than MRI alone for determining local tumor spread and distant metastasis emphasizing the added value of PET over MRI alone in staging of cervical cancer. Tumor SUVmax/ADC ratio may predict pelvic nodal involvement.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40644-020-00372-5.

Impact of PET/MRI in the Treatment of Pancreatic Adenocarcinoma: a Retrospective Cohort Study

PURPOSE

Imaging is central to the diagnosis and management of Pancreatic Ductal Adenocarcinoma (PDAC). This study evaluated if positron emission tomography (PET)/magnetic resonance imaging (MRI) elicited treatment modifications in PDAC when compared to standard of care imaging (SCI).

PROCEDURES

This retrospective study included consecutive patients with PDAC who underwent 2-deoxy-2-[¹⁸F]fluoro-D-glucose ([¹⁸F]F-FDG) PET/MRI and SCI from May 2017 to January 2019. SCI included abdominal computed tomography (CT), MRI, and/or PET/CT. For patients who had more than one pair of PET/MRI and SCI, each management decision was independently evaluated. Treatment strategies based on each modality were extracted from electronic medical records. Follow-up was evaluated until January 2020.

RESULTS

Twenty-five patients underwent 37 PET/MRI's, mean age was 65 ± 9 years and 13 (13/25, 52 %) were men. 49 % (18/37, 95 % CI 33-64 %) of the PET/MRI scans changed clinical management. Whether the SCI included a PET/CT or not did not significantly modify the probability of management change (OR = 0.9, 95 % CI 0.2-4, p = 1). One hundred percent (33/33) of the available follow-up data confirmed PET/MRI findings.

CONCLUSIONS

PET/MRI significantly changed PDAC management, consistently across the different SCI modalities it was compared to. These findings suggest a role for PET/MRI in the management of PDAC.

Impact of diffusion weighted magnetic resonance imaging in diagnosis of cervical cancer

Background

Cervical cancer is a widespread cancer among women worldwide. In this study, we evaluated the role of diffusion weighted magnetic resonance imaging (DWI-MRI) in diagnosis of cervical carcinoma with pathological diagnosis taken as the reference. The study included 70 patients in whom cancer cervix had been suspected clinically or by transvaginal U/S and confirmed by biopsy. The control group consisted of 40 patients with a normal cervix who performed MRI for other pelvic disorders. Pelvic MR with DWI and dynamic contrast enhanced MRI (DCE-MR) were done for all patients.

Results

Both DW-MRI and DCE-MRI revealed the same sensitivity, specificity, PPV, and accuracy; 100%, 50%, 97%, and 97%, respectively. The mean ADC value for malignant lesions was (0.82 × 10−3 ± 0.1 SD mm2/s). While the mean ADC value in the control group is (1.56 × 10–3 mm2/s). ADC value of (1.07 × 10−3 mm2/s) is a cut-off between normal cervical tissue& malignant cervical lesion with a sensitivity 97% and specificity 95.5%

Conclusion

Each of the (DW-MRI) and (DCE-MRI) sequences when added to the non-contrast MRI sequences in the estimation of cancer cervix had elicited the same sensitivity, specificity, and accuracy. DW–MRI was significantly beneficial in terms of diagnostic performance. For patients who cannot receive contrast medium, dynamic contrast-enhanced imaging can be replaced by DWI. The ADC value in case of cervical cancer was significantly lower than in the non-affected cervical tissue.

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.

Fluorodeoxyglucose positron-emission tomography-magnetic resonance hybrid imaging: An emerging tool for staging of cancer of the uterine cervix

Positron-emission tomography-magnetic resonance imaging (PET-MRI) is an emerging hybrid imaging modality that utilizes the superior soft tissue resolution of MR with the metabolic data from PET. In this study, we sought to assess the clinical value of fluorodeoxyglucose (FDG) PET-MRI with dedicated pelvic PET-MR in the initial staging of cervical cancer. In this institutional-approved study, we identified 23 adult females who underwent FDG PET-MRI on hybrid camera for staging of primary uterine cervical cancer that included a dedicated PET-MR of the pelvis. A nuclear medicine physician and a radiologist reviewed the PET, MRI, and fusion-body and pelvis images alone and then with consensus read characterizing PET and MR abnormal findings. There were 23 patients who underwent FDG PET-MRI for initial staging of cervical cancer with an average age of 52.2 ± 14.0 years. A total of 23 suspected lymph nodes in eight different patients were detected within the pelvis with increased metabolic activity on PET. Both the dedicated pelvis and whole-body PET imaging detected the same corresponding pelvic lymph nodes, although the pelvic PET imaging had better lymph node uptake delineation due to longer acquisition time. Using a 10-mm short-axis criterion, MRI identified only 43.5% of the FDG avid lymph nodes. The average SUVmax on the pelvis PET sequences was higher with SUV 8.9 ± 5.2 compared to the whole-body PET with SUV 7.8 ± 5.4 but was not statistically significant (P > 0.05). Primary cervical cancer was identified in 18 patients on both PET imaging and MRI with dedicated MR pelvis providing better characterization. Based on our results of the patients with cervical cancer evaluated for initial staging, combining dedicated pelvic PET-MRI with whole-body PET/MR provides the most complete status of malignant disease in reference to delineation of primary tumor, involvement of surrounding tissues, and regional lymph nodes.

PET/MRI in Cervical Cancer: Associations Between Imaging Biomarkers and Tumor Stage, Disease Progression, and Overall Survival

BACKGROUND

Positron emission tomography (PET)/MRI biomarkers have been shown to have prognostic significance in patients with cervical cancer. Their associations with progression-free survival (PFS) and overall survival (OS) merit further investigation.

PURPOSE

To evaluate the association between PET/MRI biomarkers and tumor stage, PFS, and OS in patients with cervical cancer.

STUDY TYPE

Prospective cohort study.

POPULATION

In all, 54 patients with newly diagnosed cervical cancer and measurable tumors (>1 cm) were included in the image analysis.

FIELD STRENGTH/SEQUENCE

3.0T integrated PET/MRI including diffusion-weighted echo-planar imaging (b = 50 and 1000 s/mm² ) and [18F]fluorodeoxyglucose PET.

ASSESSMENT

Two radiologists measured the minimum and mean apparent diffusion coefficient (ADC_min and ADC_mean ), maximum standardized uptake value (SUV_max ), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) of the primary tumors.

STATISTICAL TESTS

A Mann-Whitney U-test was used to evaluate the association between the imaging biomarkers and tumor stage. A Cox proportional hazards model was used to assess the relationships between the imaging biomarkers and survival.

RESULTS

In advanced tumors (T ≥ 1b2, M1, stage ≥ IB3), ADC_min was significantly lower and MTV, TLG, MTV/ADC_min , and TLG/ADC_min were significantly higher (P values between <0.001 and 0.036). In N1 tumors, ADC_min was significantly lower and MTV and MTV/ADC_min were significantly higher (P values between 0.005 and 0.016). In survival analysis, SUV_max was an independent predictor of PFS (hazard ratio [HR] = 4.57, P < 0.05), and ADC_min was an independent predictor of OS (HR = 0.02, P < 0.05). In subgroup analysis of patients with different stages, MTV/ADC_min was a predictor of PFS in stage I disease (P = 0.003), ADC_min (P = 0.038), and MTV (P = 0.020) in stage II, SUV_max (P = 0.006), and TLG (P = 0.006) in stage IV; and ADC_min was a predictor of OS in stage III disease (P = 0.008).

DATA CONCLUSION

PET/MRI biomarkers of cervical cancer are associated with tumor stage and survival. SUV_max and ADC_min are independent predictors of PFS and OS, respectively.

LEVEL OF EVIDENCE

1 TECHNICAL EFFICACY: 3.

Revised FIGO Staging for Cervical Cancer - A New Role for MRI

Cervical cancer is still the fourth most common malignancy in women worldwide and has a high mortality rate. The prognosis as well as the therapy depends largely on the extent of the tumor at the time of initial diagnosis. This shows the importance of correct staging of cervical cancer. In order to promote a globally uniform approach, staging of cervical cancer in the past was based on widespread examinations such as exam under anesthesia, histology from cervical conization or biopsy, systematic lymphadenectomy, cystoscopy, proctoscopy, i. v.-pyelogram and chest X-ray. However, as the primary tumor stage was often underestimated, the 2018 revised FIGO classification now permits cross-sectional imaging techniques and pathological findings to be incorporated into disease staging or an already existing stage to be adapted based on radiological findings. Thanks to its excellent soft tissue contrast, magnetic resonance imaging (MRI) is the method of choice for local-regional staging of cervical cancer, evaluating the response to treatment, detecting tumor recurrence and for follow-up examinations. It is important that radiologists interpreting pelvic MRI in case of suspected cervical cancer are familiar with the current FIGO staging system. This is the only way to determine the tumor stage as precisely as possible and thus lay the foundation for the success of therapy for patients. The aim of this review is to present the changes of the revised FIGO classification as well as to show the importance of MRI as the method of choice for local-regional tumor staging as a complement to clinical examination. KEY POINTS::   · Cervical cancer is still the world's fourth most common female cancer and has a high mortality rate.. · The FIGO classification for staging cervical cancer in the past was based on clinical and widespread examinations.. · The primary tumor stage has often been underestimated with the FIGO staging system since 2018.. · Since 2018, cross-sectional imaging techniques have been incorporated into disease staging.. · MRI is the method of choice for local-regional tumor staging, evaluation of the response to treatment, detection of tumor recurrence and possible complications.. CITATION FORMAT: · Merz J, Bossart M, Bamberg F et al. Revised FIGO Staging for Cervical Cancer - A New Role for MRI. Fortschr Röntgenstr 2020; 192: 937 - 944.

Measurement of tumor size in early cervical cancer: an ever-evolving paradigm

The major tenets in accurately assessing tumor size in patients with early stage cervical cancer currently include physical examination, imaging studies, and pathologic evaluation. It is estimated that when comparing clinical stage based on physical examination and final pathology, the concordance diminishes as stage increases: 85.4%, 77.4%, 35.3%, and 20.5% for stage IB1, IB2, IIA, and IIB, respectively. Vaginal involvement and larger tumor diameter are considered the main causes of stage inaccuracy. When considering imaging studies, magnetic resonance imaging (MRI) provides the highest level of accuracy in the assessment of cervical tumor size. Its accuracy in determining tumor location within the cervix is approximately 91% and in predicting tumor size 93%. MRI imaging is also significantly more accurate in measuring tumor size, delineating cervical tumor boundaries, and local tumor extension when compared with computed tomography (CT) scan. When comparing with pelvic ultrasound, the accuracy of both imaging techniques (MRI and pelvic ultrasound) in the assessment of tumor size in small versus large tumors is comparable. Pertaining to pathology, the depth of invasion should be measured by convention from the nearest surface epithelium, which equates to tumor thickness. In the setting where tumor is found both in the conization and hysterectomy specimen, the horizontal extent should be measured by summing the maximum horizontal measurement in the different specimens and the depth of invasion measured as the maximum depth in either specimen. A new pattern-based classification for endocervical adenocarcinomas recommends the description of patterns of invasion for human papillomavirus (HPV)-related adenocarcinomas as this is associated with differing risks of lymph node involvement.

Diagnostic performance of conventional and advanced imaging modalities for assessing newly diagnosed cervical cancer: systematic review and meta-analysis

OBJECTIVES

To review the diagnostic performance of contemporary imaging modalities for determining local disease extent and nodal metastasis in patients with newly diagnosed cervical cancer.

METHODS

Pubmed and Embase databases were searched for studies published from 2000 to 2019 that used ultrasound (US), CT, MRI, and/or PET for evaluating various aspects of local extent and nodal metastasis in patients with newly diagnosed cervical cancer. Sensitivities and specificities from the studies were meta-analytically pooled using bivariate and hierarchical modeling.

RESULTS

Of 1311 studies identified in the search, 115 studies with 13,999 patients were included. MRI was the most extensively studied modality (MRI, CT, US, and PET were evaluated in 78, 12, 9, and 43 studies, respectively). Pooled sensitivities and specificities of MRI for assessing all aspects of local extent ranged between 0.71-0.88 and 0.86-0.95, respectively. In assessing parametrial invasion (PMI), US demonstrated pooled sensitivity and specificity of 0.67 and 0.94, respectively-performance levels comparable with those found for MRI. MRI, CT, and PET performed comparably for assessing nodal metastasis, with low sensitivity (0.29-0.69) but high specificity (0.88-0.98), even when stratified to anatomical location (pelvic or paraaortic) and level of analysis (per patient vs. per site).

CONCLUSIONS

MRI is the method of choice for assessing any aspect of local extent, but where not available, US could be of value, particularly for assessing PMI. CT, MRI, and PET all have high specificity but poor sensitivity for the detection of lymph node metastases.

KEY POINTS

• Magnetic resonance imaging is the method of choice for assessing local extent. • Ultrasound may be helpful in determining parametrial invasion, especially in lower-resourced countries. • Computed tomography, magnetic resonance imaging, and positron emission tomography perform similarly for assessing lymph node metastasis, with high specificity but low sensitivity.

Multiparametric MRI-Based Radiomics Nomogram for Predicting Lymph Node Metastasis in Early-Stage Cervical Cancer

BACKGROUND

Lymph node metastasis (LNM) is a critical risk factor affecting treatment strategy and prognosis in patients with early-stage cervical cancer.

PURPOSE

To establish a multiparametric MRI (mpMRI)-based radiomics nomogram for preoperatively predicting LNM status.

STUDY TYPE

Retrospective.

POPULATION

Among 233 consecutive patients, 155 patients were randomly allocated to the primary cohort and 78 patients to the validation cohort.

FIELD STRENGTH

Radiomic features were extracted from a 1.5T mpMRI scan (T₁ -weighted imaging [T₁ WI], fat-saturated T₂ -weighted imaging [FS-T₂ WI], contrast-enhanced [CE], diffusion-weighted imaging [DWI], and apparent diffusion coefficient [ADC] maps).

ASSESSMENT

The performance of the nomogram was assessed with respect to its calibration, discrimination, and clinical usefulness. The area under the receiver operating characteristics curve (ROC AUC), accuracy, sensitivity, and specificity were also calculated.

STATISTICAL TESTS

The least absolute shrinkage and selection operator (LASSO) method was used for dimension reduction, feature selection, and radiomics signature building. Multivariable logistic regression analysis was used to develop the radiomics nomogram. An independent sample t-test and chi-squared test were used to compare the differences in continuous and categorical variables, respectively.

RESULTS

The radiomic signature allowed a good discrimination between the LNM and non-LNM groups, with a C-index of 0.856 (95% confidence interval [CI], 0.794-0.918) in the primary cohort and 0.883 (95% CI, 0.809-0.957) in the validation cohort. Additionally, the radiomics nomogram also had a good discriminating performance and yielded good calibration both in the primary and validation cohorts (C-index, 0.882 [95% CI, 0.827-0.937], C-index, 0.893 [95% CI, 0.822-0.964], respectively). Decision curve analysis demonstrated that the radiomics nomogram was clinically useful.

DATA CONCLUSION

A radiomics nomogram was developed by incorporating the radiomics signature with the MRI-reported LN status and FIGO stage. This nomogram might be used to facilitate the individualized prediction of LNM in patients with early-stage cervical cancer.

LEVEL OF EVIDENCE

3 TECHNICAL EFFICACY STAGE: 2 J. Magn. Reson. Imaging 2020;52:885-896.

The Role of Positron Emission Tomography/Magnetic Resonance Imaging in Gynecological Malignancies

Accurate oncological staging for early detection is of utmost importance in patient care and increasing the overall patient survival outcome. Hybrid imaging in the form of positron emission tomography (PET)/computed tomography has been successfully implemented in oncological imaging and, where available, has been used consistently in patients with gynecologic malignancies. The implementation of PET/magnetic resonance imaging (MRI) enables high-quality assessment of gynecological malignancies by combining the diagnostic advantages of metabolic information of PET along with the high-resolution anatomical and functional information from the MRI to provide precise information about staging, recurrence, and metastases. This article will review the various applications of PET/MRI in gynecological cancer.

What Is the Role of Imaging at Primary Diagnostic Work-Up in Uterine Cervical Cancer?

PURPOSE OF REVIEW

For uterine cervical cancer, the recently revised International Federation of Gynecology and Obstetrics (FIGO) staging system (2018) incorporates imaging and pathology assessments in its staging. In this review we summarize the reported staging performances of conventional and novel imaging methods and provide an overview of promising novel imaging methods relevant for cervical cancer patient care.

RECENT FINDINGS

Diagnostic imaging during the primary diagnostic work-up is recommended to better assess tumor extent and metastatic disease and is now reflected in the 2018 FIGO stages 3C1 and 3C2 (positive pelvic and/or paraaortic lymph nodes). For pretreatment local staging, imaging by transvaginal or transrectal ultrasound (TVS, TRS) and/or magnetic resonance imaging (MRI) is instrumental to define pelvic tumor extent, including a more accurate assessment of tumor size, stromal invasion depth, and parametrial invasion. In locally advanced cervical cancer, positron emission tomography-computed tomography (PET-CT) or computed tomography (CT) is recommended, since the identification of metastatic lymph nodes and distant metastases has therapeutic consequences. Furthermore, novel imaging techniques offer visualization of microstructural and functional tumor characteristics, reportedly linked to clinical phenotype, thus with a potential for further improving risk stratification and individualization of treatment. Diagnostic imaging by MRI/TVS/TRS and PET-CT/CT is instrumental for pretreatment staging in uterine cervical cancer and guides optimal treatment strategy. Novel imaging techniques may also provide functional biomarkers with potential relevance for developing more targeted treatment strategies in cervical cancer.

Measurement Repeatability of 18F-FDG PET/CT Versus 18F-FDG PET/MRI in Solid Tumors of the Pelvis

Knowledge of the within-subject variability of ¹⁸F-FDG PET/MRI measurements is necessary for proper interpretation of quantitative PET or MRI metrics in the context of therapeutic efficacy assessments with integrated PET/MRI scanners. The goal of this study was to determine the test–retest repeatability of these metrics on PET/MRI, with comparison to similar metrics acquired by PET/CT. Methods: This prospective study enrolled subjects with pathology-proven pelvic malignancies. Baseline imaging consisted of PET/CT immediately followed by PET/MRI, using a single 370-MBq ¹⁸F-FDG dose. Repeat imaging was performed within 7 d using an identical imaging protocol, with no oncologic therapy between sessions. PET imaging on both scanners consisted of a list-mode acquisition at a single pelvic station. The MRI consisted of 2-point Dixon imaging for attenuation correction, standard sequences for anatomic correlation, and diffusion-weighted imaging. PET data were statically reconstructed using various frame durations and minimizing uptake time differences between sessions. SUV metrics were extracted for both PET/CT and PET/MRI in each imaging session. Apparent diffusion coefficient (ADC) metrics were extracted for both PET/MRI sessions. Results: The study cohort consisted of 14 subjects (13 female, 1 male) with various pelvic cancers (11 cervical, 2 rectal, 1 endometrial). For SUV_max, the within-subject coefficient of variation (wCV) appeared higher for PET/CT (8.5%–12.8%) than PET/MRI (6.6%–8.7%) across all PET reconstructions, though with no significant repeatability differences (all P values ≥ 0.08) between modalities. For lean body mass-adjusted SUV_peak, the wCVs appeared similar for PET/CT (9.9%–11.5%) and PET/MRI (9.2%–11.3%) across all PET reconstructions, again with no significant repeatability differences (all P values ≥ 0.14) between modalities. For PET/MRI, the wCV for ADC_median of 3.5% appeared lower than the wCVs for SUV_max (6.6%–8.7%) and SUL_peak (9.2%–11.3%), though without significant repeatability differences (all P values ≥ 0.23). Conclusion: For solid tumors of the pelvis, the repeatability of the evaluated SUV and ADC metrics on ¹⁸F-FDG PET/MRI is both acceptably high and similar to previously published values for ¹⁸F-FDG PET/CT and MRI, supporting the use of ¹⁸F-FDG PET/MRI for quantitative oncologic treatment response assessments.

Cervical Cancer: Associations between Metabolic Parameters and Whole Lesion Histogram Analysis Derived from Simultaneous 18F-FDG-PET/MRI

Multimodal imaging has been increasingly used in oncology, especially in cervical cancer. By using a simultaneous positron emission (PET) and magnetic resonance imaging (MRI, PET/MRI) approach, PET and MRI can be obtained at the same time which minimizes motion artefacts and allows an exact imaging fusion, which is especially important in anatomically complex regions like the pelvis. The associations between functional parameters from MRI and ¹⁸F-FDG-PET reflecting different tumor aspects are complex with inconclusive results in cervical cancer. The present study correlates histogram analysis and ¹⁸F-FDG-PET parameters derived from simultaneous FDG-PET/MRI in cervical cancer. Overall, 18 female patients (age range: 32–79 years) with histopathologically confirmed squamous cell cervical carcinoma were retrospectively enrolled. All 18 patients underwent a whole-body simultaneous ¹⁸F-FDG-PET/MRI, including diffusion-weighted imaging (DWI) using b-values 0 and 1000 s/mm². Apparent diffusion coefficient (ADC) histogram parameters included several percentiles, mean, min, max, mode, median, skewness, kurtosis, and entropy. Furthermore, mean and maximum standardized uptake values (SUV_mean and SUV_max), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) were estimated. No statistically significant correlations were observed between SUV_max or SUV_mean and ADC histogram parameters. TLG correlated inversely with p25 (r=−0.486, P=0.041), p75 (r=−0.490, P=0.039), p90 (r=−0.513, P=0.029), ADC median (r=−0.497, P=0.036), and ADC mode (r=−0.546, P=0.019). MTV also showed significant correlations with several ADC parameters: mean (r=−0.546, P=0.019), p10 (r=−0.473, P=0.047), p25 (r=−0.569, P=0.014), p75 (r=−0.576, P=0.012), p90 (r=−0.585, P=0.011), ADC median (r=−0.577, P=0.012), and ADC mode (r=−0.597, P=0.009). ADC histogram analysis and volume-based metabolic 18F-FDG-PET parameters are related to each other in cervical cancer.

18F-FDG-PET/CT guided external beam radiotherapy volumes in inoperable uterine cervical cancer

BACKGROUND

In patients with advanced stage cancer of the uterine cervix who undergo irradiation with curative intent, there is the necessity to treat all suspicious nodes on imaging. Our hypothesis was that adding fluorodeoxyglucose positron emission computer tomography/computer tomography (FDG-PET/CT) to the imaging workup would alter the external beam radiotherapy (EBRT) treatment plan, either resulting in an extended external beam radiotherapy (EBRT) field to the para-aortal region or an additional boost to suspicious nodes. Since extended field radiotherapy or additional boost can cause toxicity, our secondary aim was to assess the incidence of severe late bowel toxicity in patients treated with extended para-aortal EBRT-field and boost compared to elective pelvic radiotherapy.

METHODS

Eighty-eight patients were enrolled. First, the optimal radiation treatment plan (EBRT and boost) was retrospectively determined based on magnetic resonance imaging (MRI) or FDG-PET/CT. Second, the severe bowel toxicity caused by the extended para-aortal field was assessed, based on the executed radiotherapy.

RESULTS

Based on MRI 8/88 patients would receive EBRT with para-aortic extension, this was 21/88 for FDG-PET/CT. Based on MRI 47/704 lymph node regions would receive additional boost, while based on PET/CT 91/704. Late severe bowel toxicity was seen in 12/84 patients, 6/65 in the group who received elective pelvic irradiation and 6/19 with para-aortal EBRT and boost at common iliac and/or para-aortal lymph nodes. Significant worse overall survival was seen of patients who needed para-aortal irradiation.

CONCLUSIONS

Addition of FDG-PET/CT leads to an extension of the elective EBRT volume and more suspicious lymph nodes receive a boost. However, when deciding to intensify radiation therapy, late severe bowel toxicity has to be taken into account.