Guofu Zhang

MR volumetry in predicting the aggressiveness of endometrioid adenocarcinoma: correlation with final pathological results

Background Magnetic resonance (MR) has been widely used in predicting the aggressiveness of endometrioid adenocarcinoma. However, the diagnostic value of the MR volume of the lesion has been controversial. Purpose To determine whether the whole-lesion MR volume measurement could be used as a better predictor for evaluating the aggressiveness of endometrioid adenocarcinoma. Material and Methods In this retrospective study, we include 357 patients with pathologically demonstrated endometrioid adenocarcinoma at our institution between 1 January 2013 and 31 December 2018. Whole-lesion MR volume was calculated on sagittal T2-weighted images with ITK-SNAP software on a personal computer. Results According to the receiver operating characteristics curve analysis, whole-lesion MR volume has the competitive advantage in evaluating deep myometrial invasion compared with the frozen results, generating area under the curve (AUC) values of 0.751 vs. 0.834 ( P = 0.0629, Z = 1.860). The AUC of tumor maximum diameter, simple tumor volume, and whole-lesion MR volume in predicting deep myometrial invasion was 63.8%, 67.6%, and 75.1%, respectively. Conclusion Whole-lesion MR volume is a good diagnostic tool for prediction of deep myometrial invasion, lymph node metastasis, and lymphovascular invasion. MR volumetry could reflect the aggressiveness of endometrioid adenocarcinoma more accurately than traditional lesion measurements.

MRI‐Based Machine Learning for Differentiating Borderline From Malignant Epithelial Ovarian Tumors: A Multicenter Study

BackgroundPreoperative differentiation of borderline from malignant epithelial ovarian tumors (BEOT from MEOT) can impact surgical management. MRI has improved this assessment but subjective interpretation by radiologists may lead to inconsistent results.PurposeTo develop and validate an objective MRI‐based machine‐learning (ML) assessment model for differentiating BEOT from MEOT, and compare the performance against radiologists' interpretation.Study TypeRetrospective study of eight clinical centers.PopulationIn all, 501 women with histopathologically‐confirmed BEOT (n = 165) or MEOT (n = 336) from 2010 to 2018 were enrolled. Three cohorts were constructed: a training cohort (n = 250), an internal validation cohort (n = 92), and an external validation cohort (n = 159).Field Strength/SequencePreoperative MRI within 2 weeks of surgery. Single‐ and multiparameter (MP) machine‐learning assessment models were built utilizing the following four MRI sequences: T2‐weighted imaging (T2WI), fat saturation (FS), diffusion‐weighted imaging (DWI), apparent diffusion coefficient (ADC), and contrast‐enhanced (CE)‐T1WI.AssessmentDiagnostic performance of the models was assessed for both whole tumor (WT) and solid tumor (ST) components. Assessment of the performance of the model in discriminating BEOT vs. early‐stage MEOT was made. Six radiologists of varying experience also interpreted the MR images.Statistical TestsMann–Whitney U‐test: significance of the clinical characteristics; chi‐square test: difference of label; DeLong test: difference of receiver operating characteristic (ROC).ResultsThe MP‐ST model performed better than the MP‐WT model for both the internal validation cohort (area under the curve [AUC] = 0.932 vs. 0.917) and external validation cohort (AUC = 0.902 vs. 0.767). The model showed capability in discriminating BEOT vs. early‐stage MEOT, with AUCs of 0.909 and 0.920, respectively. Radiologist performance was considerably poorer than both the internal (mean AUC = 0.792; range, 0.679–0.924) and external (mean AUC = 0.797; range, 0.744–0.867) validation cohorts.Data ConclusionPerformance of the MRI‐based ML model was robust and superior to subjective assessment of radiologists. If our approach can be implemented in clinical practice, improved preoperative prediction could potentially lead to preserved ovarian function and fertility for some women.Level of EvidenceLevel 4.Technical EfficacyStage 2. J. Magn. Reson. Imaging 2020;52:897–904.

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

BackgroundLymph node metastasis (LNM) is a critical risk factor affecting treatment strategy and prognosis in patients with early‐stage cervical cancer.PurposeTo establish a multiparametric MRI (mpMRI)‐based radiomics nomogram for preoperatively predicting LNM status.Study TypeRetrospective.PopulationAmong 233 consecutive patients, 155 patients were randomly allocated to the primary cohort and 78 patients to the validation cohort.Field StrengthRadiomic features were extracted from a 1.5T mpMRI scan (T1‐weighted imaging [T1WI], fat‐saturated T2‐weighted imaging [FS‐T2WI], contrast‐enhanced [CE], diffusion‐weighted imaging [DWI], and apparent diffusion coefficient [ADC] maps).AssessmentThe 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 TestsThe 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.ResultsThe 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 ConclusionA 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 Evidence3Technical Efficacy Stage2 J. Magn. Reson. Imaging 2020;52:885–896.

Deep Learning Nomogram for the Identification of Deep Stromal Invasion in Patients With Early‐Stage Cervical Adenocarcinoma and Adenosquamous Carcinoma: A Multicenter Study

BackgroundDeep stromal invasion (DSI) is one of the predominant risk factors that determined the types of radical hysterectomy (RH). Thus, the accurate assessment of DSI in cervical adenocarcinoma (AC)/adenosquamous carcinoma (ASC) can facilitate optimal therapy decision.PurposeTo develop a nomogram to identify DSI in cervical AC/ASC.Study TypeRetrospective.PopulationSix hundred and fifty patients (mean age of 48.2 years) were collected from center 1 (primary cohort, 536), centers 2 and 3 (external validation cohorts 1 and 2, 62 and 52).Field Strength/Sequence5‐T, T2‐weighted imaging (T2WI, SE/FSE), diffusion‐weighted imaging (DWI, EPI), and contrast‐enhanced T1‐weighted imaging (CE‐T1WI, VIBE/LAVA).AssessmentThe DSI was defined as the outer 1/3 stromal invasion on pathology. The region of interest (ROI) contained the tumor and 3 mm peritumoral area. The ROIs of T2WI, DWI, and CE‐T1WI were separately imported into Resnet18 to calculate the DL scores (TDS, DDS, and CDS). The clinical characteristics were retrieved from medical records or MRI data assessment. The clinical model and nomogram were constructed by integrating clinical independent risk factors only and further combining DL scores based on primary cohort and were validated in two external validation cohorts.Statistical TestsStudent's t‐test, Mann–Whitney U test, or Chi‐squared test were used to compare differences in continuous or categorical variables between DSI‐positive and DSI‐negative groups. DeLong test was used to compare AU‐ROC values of DL scores, clinical model, and nomogram.ResultsThe nomogram integrating menopause, disruption of cervical stromal ring (DCSRMR), DDS, and TDS achieved AU‐ROCs of 0.933, 0.807, and 0.817 in evaluating DSI in primary and external validation cohorts. The nomogram had superior diagnostic ability to clinical model and DL scores in primary cohort (all P < 0.0125 [0.05/4]) and CDS (P = 0.009) in external validation cohort 2.Data ConclusionThe nomogram achieved good performance for evaluating DSI in cervical AC/ASC.Level of Evidence3Technical EfficacyStage 2