Weibull parametric model for survival analysis in women with endometrial cancer using clinical and T2-weighted MRI radiomic features

BACKGROUND

Semiparametric survival analysis such as the Cox proportional hazards (CPH) regression model is commonly employed in endometrial cancer (EC) study. Although this method does not need to know the baseline hazard function, it cannot estimate event time ratio (ETR) which measures relative increase or decrease in survival time. To estimate ETR, the Weibull parametric model needs to be applied. The objective of this study is to develop and evaluate the Weibull parametric model for EC patients' survival analysis.

METHODS

Training (n = 411) and testing (n = 80) datasets from EC patients were retrospectively collected to investigate this problem. To determine the optimal CPH model from the training dataset, a bi-level model selection with minimax concave penalty was applied to select clinical and radiomic features which were obtained from T2-weighted MRI images. After the CPH model was built, model diagnostic was carried out to evaluate the proportional hazard assumption with Schoenfeld test. Survival data were fitted into a Weibull model and hazard ratio (HR) and ETR were calculated from the model. Brier score and time-dependent area under the receiver operating characteristic curve (AUC) were compared between CPH and Weibull models. Goodness of the fit was measured with Kolmogorov-Smirnov (KS) statistic.

RESULTS

Although the proportional hazard assumption holds for fitting EC survival data, the linearity of the model assumption is suspicious as there are trends in the age and cancer grade predictors. The result also showed that there was a significant relation between the EC survival data and the Weibull distribution. Finally, it showed that Weibull model has a larger AUC value than CPH model in general, and it also has smaller Brier score value for EC survival prediction using both training and testing datasets, suggesting that it is more accurate to use the Weibull model for EC survival analysis.

CONCLUSIONS

The Weibull parametric model for EC survival analysis allows simultaneous characterization of the treatment effect in terms of the hazard ratio and the event time ratio (ETR), which is likely to be better understood. This method can be extended to study progression free survival and disease specific survival.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03543215, https://clinicaltrials.gov/ , date of registration: 30th June 2017.

Machine learning and radiomics for segmentation and classification of adnexal masses on ultrasound

Ultrasound-based models exist to support the classification of adnexal masses but are subjective and rely upon ultrasound expertise. We aimed to develop an end-to-end machine learning (ML) model capable of automating the classification of adnexal masses. In this retrospective study, transvaginal ultrasound scan images with linked diagnoses (ultrasound subjective assessment or histology) were extracted and segmented from Imperial College Healthcare, UK (ICH development dataset; n = 577 masses; 1444 images) and Morgagni-Pierantoni Hospital, Italy (MPH external dataset; n = 184 masses; 476 images). A segmentation and classification model was developed using convolutional neural networks and traditional radiomics features. Dice surface coefficient (DICE) was used to measure segmentation performance and area under the ROC curve (AUC), F1-score and recall for classification performance. The ICH and MPH datasets had a median age of 45 (IQR 35-60) and 48 (IQR 38-57) years old and consisted of 23.1% and 31.5% malignant cases, respectively. The best segmentation model achieved a DICE score of 0.85 ± 0.01, 0.88 ± 0.01 and 0.85 ± 0.01 in the ICH training, ICH validation and MPH test sets. The best classification model achieved a recall of 1.00 and F1-score of 0.88 (AUC:0.93), 0.94 (AUC:0.89) and 0.83 (AUC:0.90) in the ICH training, ICH validation and MPH test sets, respectively. We have developed an end-to-end radiomics-based model capable of adnexal mass segmentation and classification, with a comparable predictive performance (AUC 0.90) to the published performance of expert subjective assessment (gold standard), and current risk models. Further prospective evaluation of the classification performance of this ML model against existing methods is required.

Development and Evaluation of Machine Learning in Whole-Body Magnetic Resonance Imaging for Detecting Metastases in Patients With Lung or Colon Cancer: A Diagnostic Test Accuracy Study

OBJECTIVES

Whole-body magnetic resonance imaging (WB-MRI) has been demonstrated to be efficient and cost-effective for cancer staging. The study aim was to develop a machine learning (ML) algorithm to improve radiologists' sensitivity and specificity for metastasis detection and reduce reading times.

MATERIALS AND METHODS

A retrospective analysis of 438 prospectively collected WB-MRI scans from multicenter Streamline studies (February 2013-September 2016) was undertaken. Disease sites were manually labeled using Streamline reference standard. Whole-body MRI scans were randomly allocated to training and testing sets. A model for malignant lesion detection was developed based on convolutional neural networks and a 2-stage training strategy. The final algorithm generated lesion probability heat maps. Using a concurrent reader paradigm, 25 radiologists (18 experienced, 7 inexperienced in WB-/MRI) were randomly allocated WB-MRI scans with or without ML support to detect malignant lesions over 2 or 3 reading rounds. Reads were undertaken in the setting of a diagnostic radiology reading room between November 2019 and March 2020. Reading times were recorded by a scribe. Prespecified analysis included sensitivity, specificity, interobserver agreement, and reading time of radiology readers to detect metastases with or without ML support. Reader performance for detection of the primary tumor was also evaluated.

RESULTS

Four hundred thirty-three evaluable WB-MRI scans were allocated to algorithm training (245) or radiology testing (50 patients with metastases, from primary 117 colon [n = 117] or lung [n = 71] cancer). Among a total 562 reads by experienced radiologists over 2 reading rounds, per-patient specificity was 86.2% (ML) and 87.7% (non-ML) (-1.5% difference; 95% confidence interval [CI], -6.4%, 3.5%; P = 0.39). Sensitivity was 66.0% (ML) and 70.0% (non-ML) (-4.0% difference; 95% CI, -13.5%, 5.5%; P = 0.344). Among 161 reads by inexperienced readers, per-patient specificity in both groups was 76.3% (0% difference; 95% CI, -15.0%, 15.0%; P = 0.613), with sensitivity of 73.3% (ML) and 60.0% (non-ML) (13.3% difference; 95% CI, -7.9%, 34.5%; P = 0.313). Per-site specificity was high (>90%) for all metastatic sites and experience levels. There was high sensitivity for the detection of primary tumors (lung cancer detection rate of 98.6% with and without ML [0.0% difference; 95% CI, -2.0%, 2.0%; P = 1.00], colon cancer detection rate of 89.0% with and 90.6% without ML [-1.7% difference; 95% CI, -5.6%, 2.2%; P = 0.65]). When combining all reads from rounds 1 and 2, reading times fell by 6.2% (95% CI, -22.8%, 10.0%) when using ML. Round 2 read-times fell by 32% (95% CI, 20.8%, 42.8%) compared with round 1. Within round 2, there was a significant decrease in read-time when using ML support, estimated as 286 seconds (or 11%) quicker ( P = 0.0281), using regression analysis to account for reader experience, read round, and tumor type. Interobserver variance suggests moderate agreement, Cohen κ = 0.64; 95% CI, 0.47, 0.81 (with ML), and Cohen κ = 0.66; 95% CI, 0.47, 0.81 (without ML).

CONCLUSIONS

There was no evidence of a significant difference in per-patient sensitivity and specificity for detecting metastases or the primary tumor using concurrent ML compared with standard WB-MRI. Radiology read-times with or without ML support fell for round 2 reads compared with round 1, suggesting that readers familiarized themselves with the study reading method. During the second reading round, there was a significant reduction in reading time when using ML support.

An Integrated Clinical-MR Radiomics Model to Estimate Survival Time in Patients With Endometrial Cancer

BACKGROUND

Determination of survival time in women with endometrial cancer using clinical features remains imprecise. Features from MRI may improve the survival estimation allowing improved treatment planning.

PURPOSE

To identify clinical features and imaging signatures on T2-weighted MRI that can be used in an integrated model to estimate survival time for endometrial cancer subjects.

STUDY TYPE

Retrospective.

POPULATION

Four hundred thirteen patients with endometrial cancer as training (N = 330, 66.41 ± 11.42 years) and validation (N = 83, 67.60 ± 11.89 years) data and an independent set of 82 subjects as testing data (63.26 ± 12.38 years).

FIELD STRENGTH/SEQUENCE

1.5-T and 3-T scanners with sagittal T2-weighted spin echo sequence.

ASSESSMENT

Tumor regions were manually segmented on T2-weighted images. Features were extracted from segmented masks, and clinical variables including age, cancer histologic grade and risk score were included in a Cox proportional hazards (CPH) model. A group least absolute shrinkage and selection operator method was implemented to determine the model from the training and validation datasets.

STATISTICAL TESTS

A likelihood-ratio test and decision curve analysis were applied to compare the models. Concordance index (CI) and area under the receiver operating characteristic curves (AUCs) were calculated to assess the model.

RESULTS

Three radiomic features (two image intensity and volume features) and two clinical variables (age and cancer grade) were selected as predictors in the integrated model. The CI was 0.797 for the clinical model (includes clinical variables only) and 0.818 for the integrated model using training and validation datasets, the associated mean AUC value was 0.805 and 0.853. Using the testing dataset, the CI was 0.792 and 0.882, significantly different and the mean AUC was 0.624 and 0.727 for the clinical model and integrated model, respectively.

DATA CONCLUSION

The proposed CPH model with radiomic signatures may serve as a tool to improve estimated survival time in women with endometrial cancer.

EVIDENCE LEVEL

4 TECHNICAL EFFICACY: Stage 2.

Prediction of Deep Myometrial Infiltration, Clinical Risk Category, Histological Type, and Lymphovascular Space Invasion in Women with Endometrial Cancer Based on Clinical and T2-Weighted MRI Radiomic Features

PURPOSE

To predict deep myometrial infiltration (DMI), clinical risk category, histological type, and lymphovascular space invasion (LVSI) in women with endometrial cancer using machine learning classification methods based on clinical and image signatures from T2-weighted MR images.

METHODS

A training dataset containing 413 patients and an independent testing dataset consisting of 82 cases were employed in this retrospective study. Manual segmentation of the whole tumor volume on sagittal T2-weighted MRI was performed. Clinical and radiomic features were extracted to predict: (i) DMI of endometrial cancer patients, (ii) endometrial cancer clinical high-risk level, (iii) histological subtype of tumor, and (iv) presence of LVSI. A classification model with different automatically selected hyperparameter values was created. The area under the curve (AUC) of the receiver operating characteristic (ROC) curve, F1 score, average recall, and average precision were calculated to evaluate different models.

RESULTS

Based on the independent external testing dataset, the AUCs for DMI, high-risk endometrial cancer, endometrial histological type, and LVSI classification were 0.79, 0.82, 0.91, and 0.85, respectively. The corresponding 95% confidence intervals (CI) of the AUCs were [0.69, 0.89], [0.75, 0.91], [0.83, 0.97], and [0.77, 0.93], respectively.

CONCLUSION

It is possible to classify endometrial cancer DMI, risk, histology type, and LVSI using different machine learning methods.

Deep pelvic infiltrating endometriosis: MRI consensus lexicon and compartment-based approach from the ENDOVALIRM group

PURPOSE

The purpose of this consensus article was to develop guidelines by a focused panel of experts to elaborate a lexicon of image interpretation, and a standardized region-based reporting of deep infiltrating endometriosis (DIE) with magnetic resonance imaging (MRI).

MATERIALS AND METHODS

Evidence-based data and expert opinion were combined using the RAND-UCLA Appropriateness Method to attain consensus guidelines. Experts scoring of pelvic compartment delineation and reporting template were collected; responses were analyzed and classified as "RECOMMENDED" versus "NOT RECOMMENDED" (when ≥ 80% consensus among experts) or uncertain (when < 80% consensus among experts).

RESULTS

Consensus regarding pelvic compartment delineation and DIE reporting was attained using the RAND-UCLA Appropriateness Method. The pelvis was divided in nine compartments and extrapelvic lesions were assigned to an additional (tenth) compartment. A consensus was also reached for each structure attributed to a compartment and each reporting template item among the experts. No consensus was reached for a normal aspect of uterosacral ligament, but a consensus was reached for an unequivocal involvement leading to a positive diagnosis and an equivocal involvement leading to uncertain diagnosis. Tailored MRI lexicon and standardized region-based report were proposed.

CONCLUSION

These consensus recommendations should be used as a guide for DIE reporting and staging with MRI. Standardized MRI compartment-based structured reporting is recommended to enable consistent accuracy and help select the best therapeutic approach.

Diagnostic Accuracy of FEC-PET/CT, FDG-PET/CT, and Diffusion-Weighted MRI in Detection of Nodal Metastases in Surgically Treated Endometrial and Cervical Carcinoma

PURPOSE

Preoperative nodal staging is important for planning treatment in cervical cancer and endometrial cancer, but remains challenging. We compare nodal staging accuracy of ¹⁸F-ethyl-choline-(FEC)-PET/CT, ¹⁸F-fluoro-deoxy-glucose-(FDG)-PET/CT, and diffusion-weighted-MRI (DW-MRI) with conventional morphologic MRI.

EXPERIMENTAL DESIGN

A prospective, multicenter observational study of diagnostic accuracy for nodal metastases was undertaken in 5 gyne-oncology centers. FEC-PET/CT, FDG-PET/CT, and DW-MRI were compared with nodal size and morphology on MRI. Reference standard was strictly correlated nodal histology. Eligibility included operable cervical cancer stage ≥ 1B1 or endometrial cancer (grade 3 any stage with myometrial invasion or grade 1-2 stage ≥ II).

RESULTS

Among 162 consenting participants, 136 underwent study DW-MRI and FDG-PET/CT and 60 underwent FEC-PET/CT. In 118 patients, 267 nodal regions were strictly correlated at histology (nodal positivity rate, 25%). Sensitivity per patient (n = 118) for nodal size, morphology, DW-MRI, FDG- and FEC-PET/CT was 40%*, 53%, 53%, 63%*, and 67% for all cases (*, P = 0.016); 10%, 10%, 20%, 30%, and 25% in cervical cancer (n = 40); 65%, 75%, 70%, 80% and 88% in endometrial cancer (n = 78). FDG-PET/CT outperformed nodal size (P = 0.006) and size ratio (P = 0.04) for per-region sensitivity. False positive rates were all <10%.

CONCLUSIONS

All imaging techniques had low sensitivity for detection of nodal metastases and cannot replace surgical nodal staging. The performance of FEC-PET/CT was not statistically different from other techniques that are more widely available. FDG-PET/CT had higher sensitivity than size in detecting nodal metastases. False positive rates were low across all methods. The low false positive rate demonstrated by FDG-PET/CT may be helpful in arbitration of challenging surgical planning decisions.

Evaluating Fallopian Tube Patency: What the Radiologist Needs to Know

Impaired tubal patency accounts for up to 35% of cases of subfertility and infertility. Hysterosalpingography (HSG) or hysterosalpingo-contrast sonography (HyCoSy) represents a first-line test in evaluating fallopian tube patency. Despite the association of HSG with ionizing radiation, HSG is a reference standard in assessing fallopian tube patency and tubal conditions such as tubal occlusion, salpingitis isthmica nodosa, and hydrosalpinx. HSG is widely available and utilizes either a water-soluble contrast medium (WSCM) or an oil-soluble contrast medium (OSCM). Compared with WSCM, HSG with OSCM results in a higher incidence of non-in vitro fertilization pregnancies and, therefore, may be preferred in women younger than 38 years with unexplained subfertility. HSG may also be helpful in assessment after sterilization or before fallopian tube recanalization. US-based tubal tests are free of ionizing radiation and include HyCoSy, with either air-saline or microbubble US contrast material, and hysterosalpingo-foam sonography (HyFoSy), a tubal patency test that utilizes a gel foam. A comprehensive US infertility evaluation of the pelvis and fallopian tubes can be achieved in one setting by adding coronal three-dimensional imaging of the uterus, saline infusion sonohysterography, and HyCoSy or HyFoSy to routine pelvic US. MR HSG and virtual CT HSG also depict tubal patency and uterine and adnexal pathologic conditions and may be considered in select patients. While laparoscopic chromopertubation remains the standard for tubal patency evaluation, its disadvantages are its invasiveness and cost. Knowledge of the different fallopian tube tests and radiologic appearance of normal and abnormal fallopian tubes results in fewer pitfalls, accurate interpretation, and optimal patient care. Online supplemental material is available for this article. ^©RSNA, 2021.

Ovary: MRI characterisation and O-RADS MRI

Ultrasound has a high specificity for the diagnosis of a benign lesion in cases of classic appearing simple cyst, hemorrhagic cyst, endometrioma and dermoid. However, ultrasound can sometimes be limited for definitive characterisation and risk stratification of other types of lesions, including those with echogenic content that may appear solid, with or without blood flow. Frequently, MRI can be used to further characterise these types of lesions, due to its ability to distinguish solid tissue from non-tissue solid components such as fat, blood, or debris. Incorporating the MR imaging into the evaluation of adnexal lesions can improve diagnostic certainty and guide clinical management potentially avoiding inappropriate surgery for benign lesions and expediting appropriate treatment for malignant lesions, particularly in the females with sonographically indeterminate adnexal lesions.

Adnexal Torsion: Review of Radiologic Appearances

Adnexal torsion is the twisting of the ovary, and often of the fallopian tube, on its ligamental supports, resulting in vascular compromise and ovarian infarction. The definitive management is surgical detorsion, and prompt diagnosis facilitates preservation of the ovary, which is particularly important because this condition predominantly affects premenopausal women. The majority of patients present with severe acute pain, vomiting, and a surgical abdomen, and the diagnosis is often made clinically with corroborative US. However, the symptoms of adnexal torsion can be variable and nonspecific, making an early diagnosis challenging unless this condition is clinically suspected. When adnexal torsion is not clinically suspected, CT or MRI may be performed. Imaging has an important role in identifying adnexal torsion and accelerating definitive treatment, particularly in cases in which the diagnosis is not an early consideration. Several imaging features are characteristic of adnexal torsion and can be seen to varying degrees across different modalities: a massive, edematous ovary migrated to the midline; peripherally displaced ovarian follicles resembling a string of pearls; a benign ovarian lesion acting as a lead mass; surrounding inflammatory change or free fluid; and the uterus pulled toward the side of the affected ovary. Hemorrhage and absence of internal flow or enhancement are suggestive of ovarian infarction. Pertinent conditions to consider in the differential diagnosis are a ruptured hemorrhagic ovarian cyst, massive ovarian edema, ovarian hyperstimulation, and a degenerating leiomyoma. Online supplemental material is available for this article. ^©RSNA, 2021.

2018 FIGO Staging Classification for Cervical Cancer: Added Benefits of Imaging

Cervical cancer is the fourth most common cancer in women of all ages worldwide. The disease is staged using the International Federation of Gynecology and Obstetrics (FIGO) system, which was updated in 2018. The authors explain the key changes from the 2009 version and the rationale behind them. The changes have been made to reflect common clinical practice, differentiate prognostic outcomes, and guide treatment stratification. Treatment options are dependent on the stage of disease and include fertility-sparing and non-fertility-sparing surgical options as well as chemoradiotherapy for locally advanced disease. The updated FIGO staging gives added importance to MRI as a method of accurately measuring tumor size and depicting the presence of parametrial involvement. With the inclusion of lymph node involvement in the updated 2018 FIGO staging, cross-sectional imaging-and in particular, fluorodeoxyglucose PET/CT-has an increasing role in the depiction of nodal disease. Understanding the radiologic techniques used, the literature supporting them, and common imaging pitfalls ensures accurate staging of disease and optimization of treatment. ^©RSNA, 2020 See discussion on this article by Javitt (pp 1823-1824).

Patient deprivation and perceived scan burden negatively impact the quality of whole-body MRI

AIM

To evaluate the association between the image quality of cancer staging whole-body magnetic resonance imaging (WB-MRI) and patient demographics, distress, and perceived scan burden.

MATERIALS AND METHODS

A sample of patients recruited prospectively to multicentre trials comparing WB-MRI with standard scans for staging lung and colorectal cancer were invited to complete two questionnaires. The baseline questionnaire, administered at recruitment, collated data on demographics, distress and co-morbidity. The follow-up questionnaire, completed after staging investigations, measured perceived WB-MRI scan burden (scored 1 low to 7 high). WB-MRI anatomical coverage, and technical quality was graded by a radiographic technician and grading combined to categorise the scan as "optimal", "sub-optimal" or "degraded". A radiologist categorised 30 scans to test interobserver agreement. Data were analysed using the chi-square, Fisher's exact, t-tests, and multinomial regression.

RESULTS

One hundred and fourteen patients were included in the study (53 lung, 61 colorectal; average age 65.3 years, SD=11.8; 66 men [57.9%]). Overall, 45.6% (n=52), scans were classified as "optimal" quality, 39.5% (n=45) "sub-optimal", and 14.9% (n=17) as "degraded". In adjusted analyses, greater deprivation level and higher patient-reported scan burden were both associated with a higher likelihood of having a sub-optimal versus an optimal scan (odds ratio [OR]: 4.465, 95% confidence interval [CI]: 1.454 to 13.709, p=0.009; OR: 1.987, CI: 1.153 to 3.425, p=0.013, respectively). None of the variables predicted the likelihood of having a degraded scan.

CONCLUSIONS

Deprivation and patients' perceived experience of the WB-MRI are related to image quality. Tailored protocols and individualised patient management before and during WB-MRI may improve image quality.

MRI of female genital tract congenital anomalies: European Society of Urogenital Radiology (ESUR) guidelines

Objective

To develop imaging guidelines for the MR work-up of female genital tract congenital anomalies (FGTCA).

Methods

These guidelines were prepared based on a questionnaire sent to all members of the European Society of Urogenital Radiology (ESUR) Female Pelvic Imaging Working Group (FPI-WG), critical review of the literature and expert consensus decision.

Results

The returned questionnaires from 17 different institutions have shown reasonable homogeneity of practice. Recommendations with focus on patient preparation and MR protocol are proposed, as these are key to optimised examinations. Details on MR sequences and planning of uterus-orientated sequences are provided.

Conclusions

The multiplanar capabilities and soft tissue resolution of MRI provide superb characterisation of the wide spectrum of findings in FGTCA. A standardised imaging protocol and method of reporting ensures that the salient features are recognised, contributing to a correct diagnosis and classification of FGTCA, associated anomalies and complications. These imaging guidelines are based on current practice among expert radiologists in the field and incorporate up to date information regarding MR protocols and essentials of recently published classification systems.

Key Points

• MRI allows comprehensive evaluation of female genital tract congenital anomalies, in a single examination.

• A dedicated MRI protocol comprises uterus-orientated sequences and vaginal and renal evaluation.

• Integration of classification systems and structured reporting helps in successful communication of the imaging findings.

Electronic supplementary material

The online version of this article (10.1007/s00330-020-06750-8) contains supplementary material, which is available to authorized users.

Ovarian-Adnexal Reporting Data System Magnetic Resonance Imaging (O-RADS MRI) Score for Risk Stratification of Sonographically Indeterminate Adnexal Masses

IMPORTANCE

Approximately one-quarter of adnexal masses detected at ultrasonography are indeterminate for benignity or malignancy, posing a substantial clinical dilemma.

OBJECTIVE

To validate the accuracy of a 5-point Ovarian-Adnexal Reporting Data System Magnetic Resonance Imaging (O-RADS MRI) score for risk stratification of adnexal masses.

DESIGN, SETTING, AND PARTICIPANTS

This multicenter cohort study was conducted between March 1, 2013, and March 31, 2016. Among patients undergoing expectant management, 2-year follow-up data were completed by March 31, 2018. A routine pelvic MRI was performed among consecutive patients referred to characterize a sonographically indeterminate adnexal mass according to routine diagnostic practice at 15 referral centers. The MRI score was prospectively applied by 2 onsite readers and by 1 reader masked to clinical and ultrasonographic data. Data analysis was conducted between April and November 2018.

MAIN OUTCOMES AND MEASURES

The primary end point was the joint analysis of true-negative and false-negative rates according to the MRI score compared with the reference standard (ie, histology or 2-year follow-up).

RESULTS

A total of 1340 women (mean [range] age, 49 [18-96] years) were enrolled. Of 1194 evaluable women, 1130 (94.6%) had a pelvic mass on MRI with a reference standard (surgery, 768 [67.9%]; 2-year follow-up, 362 [32.1%]). A total of 203 patients (18.0%) had at least 1 malignant adnexal or nonadnexal pelvic mass. No invasive cancer was assigned a score of 2. Positive likelihood ratios were 0.01 for score 2, 0.27 for score 3, 4.42 for score 4, and 38.81 for score 5. Area under the receiver operating characteristic curve was 0.961 (95% CI, 0.948-0.971) among experienced readers, with a sensitivity of 0.93 (95% CI, 0.89-0.96; 189 of 203 patients) and a specificity of 0.91 (95% CI, 0.89-0.93; 848 of 927 patients). There was good interrater agreement among both experienced and junior readers (κ = 0.784; 95% CI, 0.743-0824). Of 580 of 1130 women (51.3%) with a mass on MRI and no specific gynecological symptoms, 362 (62.4%) underwent surgery. Of them, 244 (67.4%) had benign lesions and a score of 3 or less. The MRI score correctly reclassified the mass origin as nonadnexal with a sensitivity of 0.99 (95% CI, 0.98-0.99; 1360 of 1372 patients) and a specificity of 0.78 (95% CI, 0.71-0.85; 102 of 130 patients).

CONCLUSIONS AND RELEVANCE

In this study, the O-RADS MRI score was accurate when stratifying the risk of malignancy in adnexal masses.

Superficial myofibroblastoma of the genital tract: a case report of the imaging findings

Superficial angiomyofibroblastomas are mesenchymal tumours that occur in the genital tract and are well described pathologically. This case report reviews the imaging appearances and highlights the MRI findings, which have not been previously described. We describe the occurrence of this lesion in a vaginal cyst, which to the authors’ knowledge, has also not been previously described. The histological findings are also presented here.

Role of Imaging in Fertility-sparing Treatment of Gynecologic Malignancies

Treatments for gynecologic cancer usually result in loss of fertility due to surgery or radical radiation therapy in the pelvis. In countries with an established screening program for cervical cancer, the majority of gynecologic malignancies occur in postmenopausal women. However, a substantial number of affected women are of childbearing age and have not completed their families. In these younger women, consideration of fertility preservation may be important. This article describes the fertility-sparing treatment options that are currently available and outlines the role of imaging in the selection of eligible patients on the basis of a review of the literature. In the setting of cervical cancer, magnetic resonance (MR) imaging is used to delineate the size, position, and stage of the tumor for selection of patients who are suitable for radical trachelectomy. In patients with solitary complex adnexal masses, diffusion- and perfusion-weighted MR imaging sequences are used to categorize the likelihood of invasive or borderline malignancy for consideration of unilateral ovarian resection, with fertility preservation when possible. In patients with endometrial cancer, MR imaging is used to rule out signs of invasive disease before hormone therapy is considered. Imaging is also used at patient follow-up to detect recurrent disease; however, evidence to support this application is limited. In conclusion, imaging is an essential tool in the care of patients with gynecologic malignancies who are considering fertility-preserving treatment options. ^©RSNA, 2016.

European society of urogenital radiology (ESUR) guidelines: MR imaging of pelvic endometriosis

Abstract

Endometriosis is a common gynaecological condition of unknown aetiology that primarily affects women of reproductive age. The accepted first-line imaging modality is pelvic ultrasound. However, magnetic resonance imaging (MRI) is increasingly performed as an additional investigation in complex cases and for surgical planning. There is currently no international consensus regarding patient preparation, MRI protocols or reporting criteria. Our aim was to develop clinical guidelines for MRI evaluation of pelvic endometriosis based on literature evidence and consensus expert opinion. This work was performed by a group of radiologists from the European Society of Urogenital Radiology (ESUR), experts in gynaecological imaging and a gynaecologist expert in methodology. The group discussed indications for MRI, technical requirements, patient preparation, MRI protocols and criteria for the diagnosis of pelvic endometriosis on MRI. The expert panel proposed a final recommendation for each criterion using Oxford Centre for Evidence Based Medicine (OCEBM) 2011 levels of evidence.

Key Points

• This report provides guidelines for MRI in endometriosis.

• Minimal and optimal MRI acquisition protocols are provided.

• Recommendations are proposed for patient preparation, best MRI sequences and reporting criteria.

Electronic supplementary material

The online version of this article (doi:10.1007/s00330-016-4673-z) contains supplementary material, which is available to authorized users.

Trauma whole-body MDCT: an assessment of image quality in conventional dual-phase and modified biphasic injection

OBJECTIVE

To compare the image quality of conventional arterial and portal venous (PV) phase multidetector CT (MDCT) with two biphasic injection protocols in polytrauma patients.

METHODS

60 consecutive patients with polytrauma underwent body 256-slice MDCT with a conventional protocol or 1 of 2 single-pass biphasic protocols: Group A, arterial (30 s) and PV (60 s) phase acquisitions; Group B, "biphasic" contrast injection with a single acquisition at 60 s; and Group C, "modified biphasic" injection with a single acquisition at a 70-s delay. Images were analyzed for arterial, venous and parenchymal attenuation profiles with regions of interest in the major arteries, veins and solid abdominal organs. A 5-point scoring system was used to assess the image quality, with 5 representing excellent arterial, venous and parenchymal opacification and <3 representing non-diagnostic opacification. In addition, the effective dose (millisieverts) was compared between the groups.

RESULTS

In 93% of patients, image quality was scored as good or excellent (≥4). All studies were of satisfactory diagnostic quality. Overall, venous and arterial attenuation profiles were comparable. Attenuation profiles in the solid abdominal viscera were significantly higher (p < 0.01) using both biphasic protocols than with arterial or PV phase of conventional protocols. Effective doses were higher in Group A.

CONCLUSION

Comparable image quality can be achieved using a biphasic i.v. contrast injection protocol with single MDCT acquisition with less radiation and reduction in acquisition time.

ADVANCES IN KNOWLEDGE

For these particular biphasic injection protocols, we have shown that image quality is comparable with a conventional protocol. This has been achieved by comparing enhanced densities of specific structures, as well as gestalt scoring by assessors, on a 256-slice MDCT.

MRI reporting standard for chronic pelvic pain: consensus development

AIM

To identify radiological parameters that should be reported on gynaecological MRI in order to create a standardized assessment pro forma for reporting CPP, which may be used in clinical practice.

METHODS

Chronic pelvic pain (CPP) in females is a common problem presenting a major challenge to healthcare providers. The complex multifactorial aetiology requires a multidisciplinary approach and often necessitates diagnostic laparoscopy for assessment. MRI is emerging as a potential non-invasive alternative for evaluation of CPP; however, standardization of reporting is required for it to be used in routine clinical practice. A two-generational Delphi survey with an expert panel of 28 radiologists specializing in gynaecological MRI from across the UK was used to refine a proposed reporting template for CPP.

RESULTS

75% response rate for the first round and 79% for the second. Following the second round, agreement was reached on the structure of the pro forma and the way in which information was sought, with overall consistency of agreement between experts deemed as fair (intraclass correlation coefficient = 0.394). This was accepted as the final version by consensus.

CONCLUSION

The standardized pro forma developed in this study will form the basis for future prospective evaluation of MRI in CPP. This template could be modified for the assessment of other benign gynaecological conditions.

ADVANCES IN KNOWLEDGE

Female CPP is a significant problem presenting challenges for clinicians. MRI is often used for evaluation and standardization of techniques, and reporting is required. The pro forma developed in this study will form the basis for future prospective MRI evaluation.

Radiological predictors of cytoreductive outcomes in patients with advanced ovarian cancer

OBJECTIVE

To assess site of disease on preoperative computed tomography (CT) to predict surgical debulking in patients with ovarian cancer.

DESIGN

Two-phase retrospective cohort study.

SETTING

West London Gynaecological Cancer Centre, UK.

POPULATION

Women with stage 3 or 4, ovarian, fallopian or primary peritoneal cancer undergoing cytoreductive surgery.

METHODS

Preoperative CT images were reviewed by experienced radiologists to assess the presence or absence of disease at predetermined sites. Multivariable stepwise logistic regression models determined sites of disease which were significantly associated with surgical outcomes in the test (n = 111) and validation (n = 70) sets.

MAIN OUTCOME MEASURES

Sensitivity and specificity of CT in predicting surgical outcome.

RESULTS

Stepwise logistic regression identified that the presence of lung metastasis, pleural effusion, deposits on the large-bowel mesentery and small-bowel mesentery, and infrarenal para-aortic nodes were associated with debulking status. Logistic regression determined a surgical predictive score which was able to significantly predict suboptimal debulking (n = 94, P = 0.0001) with an area under the curve (AUC) of 0.749 (95% confidence interval [95% CI]: 0.652, 0.846) and a sensitivity of 69.2%, specificity of 71.4%, positive predictive value of 75.0% and negative predictive value of 65.2%. These results remained significant in a recent validation set. There was a significant difference in residual disease volume in the test and validation sets (P < 0.001) in keeping with improved optimal debulking rates.

CONCLUSIONS

The presence of disease at some sites on preoperative CT scan is significantly associated with suboptimal debulking and may be an indication for a change in surgical planning.

Diffusion-weighted and multiphase contrast-enhanced MRI as surrogate markers of response to neoadjuvant sunitinib in metastatic renal cell carcinoma

BACKGROUND

Current imaging criteria for categorising disease response in metastatic renal cell carcinoma (mRCC) correlate poorly with overall survival (OS) in patients on anti-angiogenic therapies. We prospectively assess diffusion-weighted and multiphase contrast-enhanced (MCE) MR imaging (MRI) as markers of outcome.

METHODS

Treatment-naive mRCC patients on a phase II trial using sunitinib completed an MRI substudy. Whole-tumour apparent diffusion coefficient (ADC) maps and histograms were generated, and mean ADC and AUC(low) (proportion of the tumour with ADC values lying below the 25th percentile of the ADC histogram) recorded. On MCE-MRI, regions of interest were drawn around the most avidly enhancing components to analyse enhancement parameters. Baseline (n=26) and treatment-related changes in surviving patients (n=20) were correlated with OS. Imaged metastases were also analysed.

RESULTS

Forty-seven per cent of the patients showed significant changes in whole-tumour mean ADC following therapy, but there was no correlation with outcome. Patients with a high baseline AUC(low) and greater-than-median AUC(low) increase had reduced OS (HR=3.67 (95% confidence interval (CI)=1.23-10.9), P=0.012 and HR=3.72 (95% CI=0.98-14.21), P=0.038, respectively). There was no correlation between MCE-MRI parameters and OS. Twenty-eight metastases were analysed and showed positive correlation with primary tumour mean ADC for individual patients (r=0.607; P<0.001).

CONCLUSION

Primary RCC ADC histogram analysis shows dynamic changes with sunitinib. Patients in whom the tumour ADC histogram demonstrated high baseline AUC(low) or a greater-than-median increase in AUC(low) with treatment had reduced OS.

Diffusion-weighted imaging of the liver: an update

Diffusion-weighted magnetic resonance imaging (DW-MRI) is now widely used as a standard imaging sequence for evaluation of the liver. The technique is easy to implement across different MRI platforms, and results in enhanced disease detection and characterization. With careful implementation, the quantitative apparent diffusion coefficient derived shows good measurement reproducibility, which can be applied for tissue characterization, the assessment of tumour response and disease prognostication. There is now a body of evidence that highlights the relative strengths and limitations of the technique for the assessment of liver diseases. The potential for more sophisticated analysis of DW-MRI data is currently being widely investigated.

In vitro and in vivo repeatability of abdominal diffusion-weighted MRI

OBJECTIVE

To study the in vitro and in vivo (abdomen) variability of apparent diffusion coefficient (ADC) measurements at 1.5 T using a free-breathing multislice diffusion-weighted (DW) MRI sequence.

METHODS

DW MRI images were obtained using a multislice spin-echo echo-planar imaging sequence with b-values=0, 100, 200, 500, 750 and 1000 s mm(-2). A flood-field phantom was imaged at regular intervals over 100 days, and 10 times on the same day on 2 occasions. 10 healthy volunteers were imaged on two separate occasions. Mono-exponential ADC maps were fitted excluding b=0. Paired analysis was carried out on the liver, spleen, kidney and gallbladder using multiple regions of interest (ROIs) and volumes of interest (VOIs).

RESULTS

The in vitro coefficient of variation was 1.3% over 100 days, and 0.5% and 1.0% for both the daily experiments. In vivo, there was no statistical difference in the group mean ADC value between visits for any organ. Using ROIs, the coefficient of reproducibility was 20.0% for the kidney, 21.0% for the gallbladder, 24.7% for the liver and 28.0% for the spleen. For VOIs, values fall to 7.7%, 6.4%, 8.6% and 9.6%, respectively.

CONCLUSION

Good in vitro repeatability of ADC measurements provided a sound basis for in vivo measurement. In vivo variability is higher and when considering single measurements in the abdomen as a whole, only changes in ADC value greater than 23.1% would be statistically significant using a two-dimensional ROI. This value is substantially lower (7.9%) if large three-dimensional VOIs are considered.

Diffusion-weighted imaging in the assessment of tumour grade in endometrial cancer

OBJECTIVE

Endometrial cancer is the most common gynaecological malignancy in developed countries. Histological grade and subtype are important prognostic factors obtained by pipelle biopsy. However, pipelle biopsy "samples" tissue and a high-grade component that requires more aggressive treatment may be missed. The purpose of the study was to assess the use of diffusion-weighted MRI (DW-MRI) in the assessment of tumour grade in endometrial lesions.

METHOD

42 endometrial lesions including 23 endometrial cancers and 19 benign lesions were evaluated with DW-MRI (1.5T with multiple b-values between 0 and 750 s mm(-2)). Visual evaluation and the calculation of mean and minimum apparent diffusion coefficient (ADC) value were performed and correlated with histology.

RESULTS

The mean and minimum ADC values for each histological grade were 1.02 ± 0.29×10(-3) mm(2) s(-1) and 0.74 ± 0.24×10(-3) mm(2) s(-1) (grade 1), 0.88 ± 0.39×10(-3) mm(2) s(-1) and 0.64 ± 0.36×10(-3) mm(2) s(-1) (grade 2), and 0.94 ± 0.32×10(-3) mm(2) s(-1) and 0.72 ± 0.36×10(-3) mm(2) s(-1) (grade 3), respectively. There was no statistically significant difference between tumour grades. However, the mean ADC value for endometrial carcinoma was 0.97 ± 0.31, which was significantly lower (p<0.0001) than that of benign endometrial pathology (1.50 ± 0.14). Applying a cut-off mean ADC value of less than 1.28 × 10(-3) mm(2) s(-1)we obtained a sensitivity, specificity, positive predictive value and negative predictive value for malignancy of 87%, 100%, 100% and 85.7%, respectively.

CONCLUSION

Tumour mean and minimum ADC values are not useful in differentiating histological tumour grade in endometrial carcinoma. However, mean ADC measurement can provide useful information in differentiating benign from malignant endometrial lesions. This information could be clinically relevant in those patients where pre-operative endometrial sampling is not possible.

Androgen- and estrogen-secreting adrenal cancers

Androgen-secreting adrenal cancers are extremely rare malignancies, accounting for only a tiny proportion of the total number of women presenting with signs of androgen excess. Estrogen-secreting adrenal cancers are rarer still. Understanding how these tumors work benefits from an appreciation of adrenal steroid biosynthesis, as it is said that secretion in cancers is an anarchic version of normal adrenal function. Selection of patients in whom we should have a high suspicion of a malignancy is vital, so that biochemical investigation and imaging is deployed appropriately. When an adrenal tumor is found to secrete androgens or estrogens to excess, it can be difficult to confirm that it is a cancer, as there is significant overlap in the secretory patterns and imaging appearances of benign and malignant disease. The most reliable indicator of malignancy in these tumors remains the presence of metastases. Treatment is essentially surgical, although the role of mitotane is one undergoing evaluation.

Acute pancreatitis: the role of imaging in diagnosis and management

Acute pancreatitis is one of the more commonly encountered aetiologies in the emergency setting and its incidence is rising. Presentations range from a mild-self limiting condition which usually responds to conservative management to one with significant morbidity and mortality in its most severe forms. While clinical criteria are necessary to make the initial diagnosis, contrast-enhanced CT is the mainstay of imaging and has a vital role in assessing the extent and evolution of the disease and its associated complications. The purpose of this article is to summarise the natural course of acute severe pancreatitis, clarify confusing nomenclature, demonstrate the morphological stages in conjunction with radiological scoring systems and illustrate the complications. We will review and illustrate the increasing and significant role interventional radiology has in the management of these patients, which are often life-saving and surgery-sparing.

Intra-abdominal fibrosis in a recent cohort of patients with neuroendocrine ('carcinoid') tumours of the small bowel

BACKGROUND

Fibrosis is a hallmark of neuroendocrine tumours (NETs) arising in the jejunum and ileum and may manifest in the mesentery and elsewhere. It is clinically important and once-established, there are few effective therapies.

AIM

To examine the frequency, radiological manifestations and clinical significance of intra-abdominal fibrosis in a patient cohort using modern cross-sectional imaging. Current prevalence is compared to historical series and correlation with cardiac fibrosis evaluated.

DESIGN

Cross-sectional, retrospective survey of a cohort of patients with mid-gut NETs from a single centre.

METHODS

Review of clinical features, biochemistry and imaging of patients with sporadic mid-gut NET and available imaging between 2002 and 2008.

RESULTS

Thirty-one patients were included: 26 (83.9%) had liver metastases and 11 (35.4%) had small-bowel wall thickening; 17 patients (55%) had mesenteric involvement, with a mass, which contained coarse calcification in seven patients and fine calcification in a further two. There was soft-tissue stranding in 13 patients (plus in a further patient with no mass) and 'indrawing' of tissues in 11 patients. Two patients had a 'misty' mesentery and two had early retroperitoneal fibrosis. Mesenteric involvement was unrelated to gender and urinary 5HIAA excretion.

CONCLUSION

Intra-abdominal fibrosis can be detected radiologically in around half of patients with mid-gut NET using contemporary cross-sectional imaging. Although not statistically significant, small-bowel obstruction was seen more frequently in the group with fibrosis. There was no relationship with cardiac fibrosis. Prospective studies are needed to evaluate predictors of fibrosis onset and clinical course and determine optimal methods of prevention and treatment.

Epithelioid angiomyolipoma: imaging appearances

Epithelioid angiomyolipoma is a recently described rare variant of renal angiomyolipoma. It can occur in patients with or without tuberous sclerosis, and may potentially be malignant. We report the imaging findings from two cases of epithelioid angiomyolipoma: the first in a patient with tuberous sclerosis complex, arising in a horse-shoe kidney and growing into the inferior vena cava and right atrium; the second in a 62-year-old hypertensive man.