High-resolution T2WI Research Articles

Association Analysis Between Intratumoral and Peritumoral MRI Radiomics Features and Overall Survival of Neoadjuvant Therapy in Rectal Cancer.

The use of peritumoral features to determine the survival time of patients with rectal cancer (RC) is still imprecise. To explore the correlation between intratumoral, peritumoral and combined features, and overall survival (OS). Retrospective. One hundred sixty-six RC patients (53 women, 113 men; average age: 55 ± 12 years) who underwent radical resection after neoadjuvant therapy. 3 T; T2WI sagittal, T1WI axial, T2WI axial with fat suppression, and high-resolution T2WI axial sequences, enhanced T1WI axial and sagittal sequences with fat suppression. Radiologist A segmented 166 patients, and radiologist B randomly segmented 30 patients. Intratumoral and peritumoral features were extracted, and features with good stability (ICC ≥0.75) were retained through intra-observer analysis. Seven classifiers, including Logistic Regression (LR), Support Vector Machine (SVM), K-Nearest Neighbors (KNN), Random Forest (RF), Extremely randomized trees (ET), eXtreme Gradient Boosting (XGBoost), and LightGBM (LGBM), were applied to select the classifier with the best performance. Next, the Rad-score of best classifier and the clinical features were selected to establish the models, thus, nomogram was built to identify the association with 1-, 3-, and 5-year OS. LASSO, regression analysis, ROC, DeLong method, Kaplan-Meier curve. P < 0.05 indicated a significant difference. Only Node (irregular tumor nodules in the surrounding mesentery) and ExtraMRF (lymph nodes outside the perirectal mesentery) were significantly different in 20 clinical features. Twelve intratumoral, 3 peritumoral, and 14 combined features related to OS were selected. LR, SVM, and RF classier showed the best efficacy in the intratumoral, peritumoral, and combined model, respectively. The combined model (AUC = 0.954 and 0.821) had better survival association than the intratumoral model (AUC = 0.833 and 0.813) and the peritumoral model (AUC = 0.824 and 0.687). The proposed peritumoral model with radiomics features may serve as a tool to improve estimated survival time. 3 TECHNICAL EFFICACY: Stage 4.

The value of multimodality MR in T staging evaluation after neoadjuvant therapy for rectal cancer.

Surgery is the preferred treatment for rectal cancer, but surgical treatment alone sometimes does not achieve satisfactory results. To explore the value of multimodal Magnetic Resonance (MR) images in evaluating T staging of rectal cancer after neoadjuvant therapy and to compare and analyze with pathological results. This study retrospectively analyzed 232 patients with stage T3, T4 rectal cancer between January 1, 2017 and October 31, 2022. MR examination was performed within 3 days before surgery. Different MR sequences were used for mrT staging of rectal cancer after neoadjuvant therapy and compared with pathological pT staging. The accuracy of different MR sequences in evaluating T staging of rectal cancer was calculated, and the consistency between the two was analyzed by kappa test. The sensitivity, specificity, negative predictive value and positive predictive value of different MR sequences in evaluating rectal cancer invading mesorectal fascia after neoadjuvant therapy were calculated. A total of 232 patients with rectal cancer were included in the study. The accuracy of high-resolution T2 WI in evaluating T staging of rectal cancer after neoadjuvant therapy was 49.57%, and the Kappa value was 0.261. The accuracy of high-resolution T2WI combined with diffusion weighted imaging (DWI) in evaluating T staging of rectal cancer after neoadjuvant therapy was 61.64%, and the Kappa value was 0.411. The accuracy of high-resolution combined with DCE-MR images in evaluating T staging of rectal cancer after neoadjuvant therapy was 80.60%, and the Kappa value was 0.706. The sensitivity and specificity of high-resolution t2-weighted imaging (HR-T2WI) combined with dynamic contrast-enhancement magnetic resonance (DCE-MR) in evaluating the invasion of mesorectal fascia were 83.46% and 95.33%, respectively. Compared with HR-T2WI combined with DWI images for mrT staging of rectal cancer after neoadjuvant chemoradiotherapy (N-CRT), HR-T2WI combined with DCE-M has the highest accuracy in evaluating mrT staging of rectal cancer after neoadjuvant therapy (80.60%), and has a high consistency with pathological pT staging. It is the best sequence for T staging of rectal cancer after neoadjuvant therapy. At the same time, the sequence has high sensitivity and specificity in evaluating mesorectal fascia invasion, which can provide accurate perioperative information for the formulation of surgical plan.

A nomogram based on MRI radiomics features of mesorectal fat for diagnosing T2- and T3-stage rectal cancer.

To develop and validate a nomogram for the preoperative diagnosis of T2 and T3 stage rectal cancer using MRI radiomics features of mesorectal fat. The data of 288 patients with T2 and T3 stage rectal cancer were retrospectively collected. Radiomics features were extracted from the lesion region of interest (ROI) in the MRI high-resolution T2WI, apparent diffusion coefficient (ADC), and diffusion-weighted imaging (DWI) sequences. After using ICC inter-group consistency analysis and Pearson correlation analysis to reduce dimensions, LASSO regression analysis was performed to select features and calculate Rad-score for each sequence. Then, Combined_Radscore and nomogram were constructed based on the LASSO-selected features and clinical data for each sequence. Receiver operating characteristic curve (ROC) area under the curve (AUC) was used to evaluate the performance of the Rad-score model and nomogram. Decision curve analysis (DCA) was performed to evaluate the clinical usability of the radiomics nomogram, which were combined with calibration curves to evaluate the prediction accuracy. The nomogram based on MRI-report T status and Combined_Radscore achieved AUCs of 0.921 and 0.889 in the training and validation cohorts, respectively. The nomogram can be stated that the radiomics nomogram based on multi-sequence MRI imaging of the mesorectal fat has excellent diagnosing performance for preoperative differentiation of T2 and T3 stage rectal cancer.

Prognostic prediction value of the clinical-radiomics tumour-stroma ratio in locally advanced rectal cancer

PurposeTo develop and validate a radiomics model based on high-resolution T2WI and a clinical-radiomics model for tumour-stroma ratio (TSR) evaluation with a gold standard of TSR evaluated by rectal specimens without therapeutic interference and further apply them in prognosis prediction of locally advanced rectal cancer (LARC) patients who received neoadjuvant chemoradiotherapy. MethodsA total of 178 patients (mean age: 59.35, range 20–85 years; 65 women and 113 men) with rectal cancer who received surgery alone from January 2016 to October 2020 were enrolled and randomly separated at a ratio of 7:3 into training and validation sets. A senior radiologist reviewed after 2 readers manually delineated the whole tumour in consensus on preoperative high-resolution T2WI in the training set. A total of 1046 features were then extracted, and recursive feature elimination embedded with leave-one-out cross validation was applied to select features, with which an MR-TSR evaluation model was built containing 6 filtered features via a support vector machine classifier trained by comparing patients’ pathological TSR. Stepwise logistic regression was employed to integrate clinical factors with the radiomics model (Fusion-TSR) in the training set. Later, the MR-TSR and Fusion-TSR models were replicated in the validation set for diagnostic effectiveness evaluation. Subsequently, 243 patients (mean age: 53.74, range 23–74 years; 63 women and 180 men) with LARC from October 2012 to September 2017 who were treated with NCRT prior to surgery and underwent standard pretreatment rectal MR examination were enrolled. The MR-TSR and Fusion-TSR were applied, and the Kaplan–Meier method and log-rank test were used to compare the survival of patients with different MR-TSR and Fusion-TSR. Cox proportional hazards regression was used to calculate the hazard ratio (HR). ResultsBoth the MR-TSR and Fusion-TSR models were validated with favourable diagnostic power: the AUC of the MR-TSR was 0.77 (p = 0.01; accuracy = 69.8 %, sensitivity = 88.9 %, specificity = 65.9 %, PPV = 34.8 %, NPV = 96.7 %), while the AUC of the Fusion-TSR was 0.76 (p = 0.014; accuracy = 67.9 %, sensitivity = 88.9 %, specificity = 63.6 %, PPV = 33.3 %, NPV = 96.6 %), outperforming their effectiveness in the training set: the AUC of the MR-TSR was 0.65 (p = 0.035; accuracy = 66.4 %, sensitivity = 61.9 %, specificity = 67.3 %, PPV = 27.7 %, NPV = 90.0 %), while the AUC of the Fusion-TSR was 0.73 (p = 0.001; accuracy = 73.6 %, sensitivity = 71.4 %, specificity = 74.0 %, PPV = 35.73 %, NPV = 92.8 %). With further prognostic analysis, the MR-TSR was validated as a significant prognostic factor for DFS in LARC patients treated with NCRT (p = 0.020, HR = 1.662, 95 % CI = 1.077–2.565), while the Fusion-TSR was a significant prognostic factor for OS (p = 0.005, HR = 2.373, 95 % CI = 1.281–4.396). ConclusionsWe developed and validated a radiomics TSR and a clinical-radiomics TSR model and successfully applied them to better risk stratification for LARC patients receiving NCRT and for better decision making.

Deep Learning-Driven Transformation: A Novel Approach for Mitigating Batch Effects in Diffusion MRI Beyond Traditional Harmonization.

"Batch effect" in MR images, due to vendor-specific features, MR machine generations, and imaging parameters, challenges image quality and hinders deep learning (DL) model generalizability. We aim to develop a DL model using contrast adjustment and super-resolution to reduce diffusion-weighted images (DWIs) diversity across magnetic field strengths and imaging parameters. Retrospective. The DL model was built using an open dataset from one individual. The MR machine identification model was trained and validated on a dataset of 1134 adults (54% females, 46% males), with 1050 subjects showing no DWI abnormalities and 84 with conditions like stroke and tumors. The 21,000 images were divided into 80% for training, 20% for validation, and 3500 for testing. Seven MR scanners from four manufacturers with 1.5 T and 3 T magnetic field strengths. DWIs were acquired using spin-echo sequences and high-resolution T2WIs using the T2-SPACE sequence. An experienced, board-certified radiologist evaluated the effectiveness of restoring high-resolution T2WI and harmonizing diverse DWI with metrics such as PSNR and SSIM, and the texture and frequency attributes were further analyzed using gray-level co-occurrence matrix and 1-dimensional power spectral density. The model's impact on machine-specific characteristics was gauged through the performance metrics of a ResNet-50 model. Comprehensive statistical tests were employed for statistical robustness, including McNemar's test and the Dice index. Our DL protocol reduced DWI contrast and resolution variation. ResNet-50 model's accuracy decreased from 0.9443 to 0.5786, precision from 0.9442 to 0.6494, recall from 0.9443 to 0.5786, and F1 score from 0.9438 to 0.5587. The t-SNE visualization indicated more consistent image features across multiple MR devices. Autoencoder halved learning iterations; Dice coefficient >0.74 confirmed signal reproducibility in 84 lesions. This study presents a DL strategy to mitigate batch effects in diffusion MR images, improving their quality and generalizability. 3 TECHNICAL EFFICACY: Stage 1.

Identifying Tumor Deposits in Patients with Locally Advanced Rectal Cancer: Using Multiplanar High-Resolution T2WI.

The prognosis of postoperative tumor deposits (TDs) is worse than positive lymph node metastases alone. To detect TDs by using multiplanar high-resolution T2-weighted imaging (HRT2WI). This retrospective study enrolled 130 patients with locally advanced rectal cancer (LARC). Using pathology-proven tumor deposits (pTDs) as the gold standard, all patients were divided into the pTDs-negative and pTDs-positive groups, the correlation of clinicopathological factors and image features [such as MRI-detected tumor deposits (mTDs), MRI-detected metastatic lymph node (mLN), MRI-detected extramural vascular invasion (mEMVI), maximal extramural depth (EMD), etc.] with pTDs were analyzed by univariate analysis and multivariate binary logistic regression analysis, and the nomogram was established based on the latter. The diagnostic efficiency was evaluated by the receiver operating characteristic curve (ROC) analysis and area under curve (AUC). mTDs, mLN, mEMVI, and EMD were significantly different between the pTDs-positive and pTDs-negative groups (P < 0.05), with the AUC of 0.767, 0.746, 0.664 and 0.644, respectively. mTDs and mLN were independent risk factors for pTDs (odds ratio: 5.74 and 3.90, P < 0.05). The AUC, sensitivity, specificity, negative predictive value, and accuracy of the nomogram were 0.814 (95% CI: 0.720 ~ 0.908), 73.9%, 79.4%, 93.4%, and 78.5%, respectively. Seventeen of 23 patients with pTDs were identified as mTDs, with a moderate agreement between pTDs and mTDs (Kappa=0.419). Multiplanar HRT2WI can be used as a preoperative diagnostic tool to identify TDs in LARC. The combined model constructed by mTDs and mLN shows a good diagnostic performance for TDs.

Development and Validation of a Radiomics Model Based on Lymph-Node Regression Grading After Neoadjuvant Chemoradiotherapy in Locally Advanced Rectal Cancer

The response to neoadjuvant chemoradiotherapy (nCRT) varies among patients with locally advanced rectal cancer (LARC), and the treatment response of lymph nodes (LNs) to nCRT is critical in implementing a watch-and-wait strategy. A robust predictive model may help personalize treatment plans to increase the chance that patients achieve a complete response. This study investigated whether radiomics features based on prenCRT magnetic resonance imaging nodes could predict treatment response in preoperative LARC LNs. The study included 78 patients with clinical stage T3-T4, N1-2, and M0 rectal adenocarcinoma who received long-course neoadjuvant radiotherapy before surgery. Pathologists evaluated 243 LNs, of which 173 and 70 were assigned to training and validation cohorts, respectively. For each LN, 3641 radiomics features were extracted from the region of interest in high-resolution T2WI magnetic resonance imaging before nCRT. The least absolute shrinkage and selection operator regression model was used for feature selection and radiomics signature building. A prediction model based on multivariate logistic analysis, combining radiomics signature and selected LN morphologic characteristics, was developed and visualized by drawing a nomogram. The model's performance was assessed by receiver operating characteristic curve analysis and calibration curves. The radiomics signature consists of 5 selected features that were effectively discriminated within the training cohort (area under the curve [AUC], 0.908; 95% CI, 0.857%-0.958%) and the validation cohort (AUC, 0.865; 95% CI, 0.757%-0.973%). The nomogram, which consisted of radiomics signature and LN morphologic characteristics (short-axis diameter and border contours), showed better calibration and discrimination in the training and validation cohorts (AUC, 0.925; 95% CI, 0.880%-0.969% and AUC, 0.918; 95% CI, 0.854%-0.983%, respectively). The decision curve analysis confirmed that the nomogram had the highest clinical utility. The nodal-based radiomics model effectively predicts LNs treatment response in patients with LARC after nCRT, which could help personalize treatment plans and guide the implementation of the watch-and-wait approach in these patients.

High-Resolution T2-Weighted Imaging for Surveillance in Postoperative Vestibular Schwannoma: Equivalence with Contrast-Enhanced T1WI for Measurement and Surveillance of Residual Tumor.

Patients with surgically resected vestibular schwannoma will undergo multiple postoperative surveillance examinations, typically including postcontrast sequences. The purpose of this study was to compare high-resolution T2WI with gadolinium T1WI in the postoperative assessment of vestibular schwannoma. This was a retrospective study of patients with a history of resected vestibular schwannoma at a single institution. High-resolution T2WI and gadolinium T1WI were independently evaluated for residual disease. In addition, 3D and 2D measurements were performed in the group of patients with residual tumor. Statistical analysis was performed to evaluate the agreement between sequences on the binary assessment (presence/absence of tumor on initial postoperative examination) and to evaluate the equivalence of measurements for the 2 sequences on 3D and 2D quantitative assessment in individuals with residual disease. One hundred forty-eight patients with retrosigmoid-approach resection of vestibular schwannomas were included in the final analysis. There was moderate-to-substantial agreement between the 2 sequences for the evaluation of the presence versus absence of tumor (Cohen κ coefficient = 0.78; 95% CI, 0.68-0.88). The 2 sequences were significantly equivalent for 2D and 3D quantitative assessments (short-axis P value = .021; long-axis P value = .015; 3D P value = .039). In this retrospective study, we demonstrate moderate-to-substantial agreement in the categoric assessment for the presence versus absence of tumor and equivalence between the 2 sequences for both 2D and volumetric tumor measurements as performed in the subset of patients with measurable residual. On the basis of these results, high-resolution T2WI alone may be sufficient for early postoperative imaging surveillance in this patient population.

High-resolution MRI demonstrates signal abnormalities of the 3rd cranial nerve in giant cell arteritis patients with 3rd cranial nerve impairment.

To determine the sensitivity and specificity of high-resolution (HR) MRI for detecting signal abnormalities of cranial nerves (CN) in giant cell arteritis (GCA) patients presenting with diplopia. This IRB-approved retrospective single-center study included GCA patients who underwent 3-T HR MRI from December 2014 to January 2020. Two radiologists, blinded to all data, individually assessed for the presence of enhancement of the 3rd, 4th, and/or 6th CN on post-contrast HR imaging and high signal intensity on HR T2-WI, for signal abnormalities of extraocular muscles and the brainstem, and for inflammatory changes of the ophthalmic and extracranial arteries. A Fisher's exact test was used to compare patients with or without diplopia. In total, 64 patients (42/64 (66%) women and 22/64 (34%) men, mean age 76.3 ± 8years) were included. Of the 64 patients, 14 (21.9%) presented with diplopia. Third CN enhancement was detected in 7/8 (87.5%) patients with 3rd CN impairment, as compared to no patients with 4th or 6th CN impairment or to patients without diplopia (p < 0.001). Third CN abnormal high signal intensity on HR T2-WI was detected in 4/5 patients (80%) with 3rd CN impairment versus none of other patients (p < 0.001). Sensitivity, specificity, positive predictive value, and negative predictive value for detecting 3rd CN signal abnormalities were of 0.88, 1, 1, and 0.99 and 0.8, 1, 1, and 0.98 for post-contrast HR imaging and HR T2-WI, respectively. HR MRI had excellent diagnostic sensitivity and specificity when detecting signal abnormalities of the 3rd CN in GCA patients presenting with 3rd CN impairment. • Third cranial nerve enhancement was detected in all patients with 3rd cranial nerve impairment except for one with transient diplopia. • The "check mark sign" might be useful to identify 3rd cranial nerve signal abnormalities in the orbital apex. • No signal abnormalities of the 4th or 6th cranial nerves could be detected on high-resolution MRI.

MRI-based radiomics nomogram to predict synchronous liver metastasis in primary rectal cancer patients.

At the time of diagnosis, approximately 15%‐20% of patients with rectal cancer (RC) presented synchronous liver metastasis (SLM), which is the most common cause of death in patients with RC. Therefore, preoperative, noninvasive, and accurate prediction of SLM is crucial for personalized treatment strategies. Recently, radiomics has been considered as an advanced image analysis method to evaluate the neoplastic heterogeneity with respect to diagnosis of the tumor and prediction of prognosis. In this study, a total of 1409 radiomics features were extracted for each volume of interest (VOI) from high‐resolution T2WI images of the primary RC. Subsequently, five optimal radiomics features were selected based on the training set using the least absolute shrinkage and selection operator (LASSO) method to construct the radiomics signature. In addition, radiomics signature combined with carcinoembryonic antigen (CEA) and carbohydrate antigen 19‐9 (CA19‐9) was included in the multifactor logistic regression to construct the nomogram model. It showed an optimal predictive performance in the validation set as compared to that in the radiomics model. The favorable calibration of the radiomics nomogram showed a nonsignificant Hosmer‐Lemeshow test statistic (P > .05). The decision curve analysis (DCA) showed that the radiomics nomogram is clinically superior to the radiomics model. Therefore, the nomogram amalgamating the radiomics signature and clinical risk factors serve as an effective quantitative approach to predict the SLM of primary RC.

Usefulness of High Resolution T2-Weighted Images in the Evaluation and Surveillance of Vestibular Schwannomas? Is Gadolinium Needed?

First aim of study was to compare the diagnostic accuracy of high resolution T2-WI (HRT2-WI) and gadolinium-enhanced T1-weighted image (Gd T1-WI) sequences in quantitative evaluation of vestibular schwannomas (VS). The second one was to determine through qualitative evaluation when Gd-injection should be recommended. Two observers in consensus retrospectively reviewed 137 magnetic resonance imaging (MRI) scans of patients with histological diagnosis of VS (33 women, 26 men), 116 with both HRT2-WI and Gd T1-WI. The examinations were subdivided in: surveillance (10), pretreatment (30), posttreatment (43), and posttreatment follow-up (33) studies. Quantitative evaluation was based on size measurement of the lesion. Structural details of the lesion, facial nerve course, and involvement of the fundus of the internal auditory canal were assessed for the qualitative evaluation in both sequences. No statistically significant changes were demonstrated between size measurement in the HRT2-WI and Gd T1-WI (p = 0.329). Sensitivity, specificity, and accuracy of HRT2-WI in the detection of lesional size were 90.4, 98.9, 92.5%, respectively. HRT2-WI was worse for characterization of structural details in pretreatment, posttreatment, and posttreatment follow-up examinations. HRT2-WI showed better or equal capability for all the groups in the demonstration of the facial nerve course. In the evaluation of the involvement of the fundus of the internal auditory canal, HRT2-WI showed worse results or had a complementary role for the posttreatment and posttreatment follow-up groups, while in the other groups was considered mainly equal or complementary. Only in the surveillance group, HRT2-WI was never worse for all the criteria. Results for quantitative evaluation were similar in both the sequences. Gadolinium injection can be avoided only in surveillance studies.

The value of diffusion kurtosis imaging in assessing mismatch repair gene expression of rectal carcinoma: Preliminary findings.

PurposeTo determine the correlation between the parameters of MR diffusion kurtosis imaging (MR-DKI) and mismatch repair gene expression (MMR) for rectal carcinomas.Materials and methodsData from 80 patients with rectal carcinoma were analyzed in this prospective study. High-resolution T2WI and DKI (b = 0, 800 and 1600 s/mm2, respectively) were performed. Mean kurtosis (MK) and mean diffusivity (MD) from DKI were measured. MMR-positive expression and HER-2 expression were classified into two groups. For comparison between different grades, the Mann-Whitney U test, receiver operating characteristic curve, and Spearman’s correlation analysis were used for statistical analyses.ResultsThe MK values in identifying positive MMR expressions (MLH1, MSH2, and MSH6) were more reliable than the MD values (rs value: 0.772 vs. 0.448, 0.733 vs. 0.499, and 0.828 vs. 0.633 respectively, P<0.01). Receiver operating curve analysis showed that the performances of the MK values were better than those of the MD values (z = 2.835, 2.000, and 2.827, respectively, P<0.05), while the performances of the MK and MD-MK values were not statistically significant (z = 0.808, 1.557, and 0.596, respectively, P>0.05). Similarly, MK values were better than MD values in identifying HER2 expression (z = 2.795, P<0.05).ConclusionsMK derived from DKI demonstrated a greater correlation than MD with MMR expression. It also showed better performance in differentiating between high- and low-grade positive MMR expression and HER2 expression. Thus, DKI may be valuable for the prognoses and evaluation of non-invasive therapies.

Added value of diffusion-weighted imaging for evaluation of extramural venous invasion in patients with primary rectal cancer.

To evaluate the added value of diffusion-weighted imaging (DWI) to T 2 weighted imaging (T 2WI) for detection of extramural venous invasion (EMVI) in patients with primary rectal cancer. 79 patients (50 men, 29 females, mean age 67.4 years, range 37-87 years) who had undergone rectal MRI and subsequently received surgical resection were included. The rectal MRI consisted of T 2WI in three planes and axial DWI (b-values, 0, 1000 s mm-2). Two radiologists blinded to the pathologic results independently reviewed the T 2WI first, and then the combined T 2WI and DWI 4 weeks later. They recorded their confidence scores for EMVI on a 5-point scale (0: definitely negative and 4: definitely positive). The diagnostic performance of each reading session for each reader was compared by pairwise comparison of receiver operating characteristic curves. The area under the ROC curve (AUC) was considered as the diagnostic performance. The result of a histopathological examination served as the reference standard for EMVI. For both readers, the diagnostic performance was not significantly different between the two image sets (for reader 1, AUC, 0.828 and 0.825, p = 0.9426 and for reader 2, AUC, 0.723 and 0.726, p = 0.9244, respectively). There was no added value of DWI to T2WI for detection of EMVI in patients with primary rectal cancer. High-resolution T2WI alone is sufficient to assess EMVI and a supplementary DWI has no added value in patients with primary rectal cancer.

Potential Clinical Benefits and Limitation of Foetal Virtuopsy Using a High-Field MRI of 7 Tesla to Assess First Trimester Foetuses Versus Stereomicroscopic Autopsy

Background: Performing accurate autopsies on small foetuses is a difficult process to achieve, especially when a certain degree of autolysis is involved. High-field MRI of 7 T has proven to be a useful tool to describe small foetuses anatomy, therefore the purpose of our study was to establish its diagnostic usefulness assessing first trimester foetuses compared to stereomicroscopic autopsy or microscopic evaluation. Methods Nine consecutive cases of first trimester foetuses were divided in two groups according to gestational age and crown-rump length (Embryo Group cases of 9-10 gestational weeks and Foetal Group cases of 13 gestational weeks) and scanned using a 3D Fast Imaging with Steady Procession 3D (FISP 3D) respectively 2D Turbo High Resolution T2 WI protocol. Images were interpreted by a radiologist, and two embryologists. All cases were submitted to invasive autopsy, blinded to the imagistic results. Findings Virtuopsy brought important additional information in all cases from the Embryo Group and had similar diagnostic capacity as the conventional method in evaluating the cases from the Foetal Group. The Cohen's kappa coefficient of agreement was k=0.92 (95% CI 82-97), highlighting a very good concordance between foetal virtuopsy and stereomicroscopic autopsy, also supported by the McNemar test p =1.00. The imagistic method presented a better capacity in visualising embryonic structure especially embryonic brain with lesser method disadvantages (p=0,005.) and similar capacity for visualising foetal structures in the second group. Interpretation Virtual autopsy using high field MRI at 7T is emerging as a promising alternative approach to stereomicroscopic autopsy in the assessment of malformed first trimester human foetuses. Funding: Not applicable. Declaration of Interest: The authors report no declarations of interest. Ethical Approval: The study protocol was approved by the “Iuliu Hatieganu” University of Medicine and Pharmacy Ethics Committee and written informed parental consent was obtained before the imagistic and conventional autopsy procedures.

Radiomic features of pretreatment MRI could identify T stage in patients with rectal cancer: Preliminary findings.

Recent studies have shown that magnetic resonance (MR) radiomic analysis is feasible and has some value in identifying tumor characteristics, but there are few data regarding the role of MR-based radiomic features in rectal cancer. The aim of this study was to determine whether radiomic features extracted from T2 -weighted imaging (T2 WI) can identify pathological features in rectal cancer. Retrospective study. A cohort comprising 119 rectal cancer patients who underwent surgery between January 2015 and November 2016. 3.0T, axial high-resolution T2 -weighted turbo spin echo (TSE) sequence. Patients were classified according to pathological features such as T stage, N stage, perineural invasion, histological grade, lymph-vascular invasion, tumor deposits, and circumferential resection margin (CRM). The whole tumor volume (WTV) was distinguished, and segments were quantified on axial high-resolution T2 WI by a radiologist. A total of 256 radiomic features were extracted. To achieve reliable results, cluster analysis and least absolute shrinkage and selection operator (LASSO) were implemented. In the cluster analysis, the patients were divided into two groups, and chi-square tests were performed to investigate the relationship between the pathological features and the radiomic-based clusters. The area under the curve (AUC) was calculated to evaluate the predictability of the model in the LASSO analysis. The cluster results revealed that patients could be stratified into two groups, and the chi-square test results indicated that the pT stage was correlated with the radiomic feature cluster results (P = 0.002). The prediction model AUC for the diagnostic T stage was 0.852 (95% confidence interval: 0.677-1; sensitivity: 79.0%, specificity: 82.0%). The use of MRI-derived radiomic features to identify the T stage is feasible in rectal cancer. 3 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018.

Preoperative staging and planning for sphincter sparing surgery in rectal carcinoma using high resolution T2WI following endorectal gel administration

PurposeTo assess the accuracy of high resolution T2WI with the addition of DWI in the preoperative staging, prediction of negative circumferential resection margin and planning of surgical management of rectal carcinoma. Patients and methodsSeventy-five patients (30 men and 45 women) with pathologically proven rectal carcinoma underwent high resolution MRI study with trans-rectal gel administration. The MRI staging was compared with the postoperative pathological staging. ResultsThe MRI Sensitivity was 98.63%, Specificity 97.3% and accuracy 97.96% in evaluation of T staging. For the assessment of lymph node involvement, the sensitivity was 98.18%, specificity 85.00%, and accuracy 94.67% in correlation with histopathological study. ConclusionHigh resolution MRI is accurate for preoperative staging, prediction of negative circumferential resection margin, lymph nodes involvement and planning the feasibility of sphincter-sparing surgery.

Gadoxetic acid-enhanced 3.0 T MRI for the evaluation of hepatic metastasis from colorectal cancer: Metastasis is not always seen as a “defect” on the hepatobiliary phase

PurposeTo determine specific imaging features of hepatic metastasis from colorectal cancer, focusing on the hepatobiliary phase (HBP) of gadoxetic acid-enhanced MRI. Materials and methodsOver a 2-year period, 79 hepatic metastatic lesions were identified from 32 patients (22 men and 10 women) who proven colorectal cancer and underwent gadoxetic acid-enhanced 3.0T MRI. Hepatic metastases were proven pathologically in 16 patients: by surgical liver resection (n=14) and by US-guided biopsy (n=2). The remaining 16 patients were considered to have hepatic metastasis based on imaging studies and clinical information. Two radiologists evaluated the imaging features of each MRI sequence, including high resolution T2WI, dynamic contrast enhancement study with hepatobiliary phase, and diffusion weighted image. We also compared SI of the lesions on T2WI and HBP. ResultsT2WI showed homogeneous high SI (n=25; 31.7%), target appearance (n=3; 3.8%), reversed target appearance (n=2; 2.6%), and heterogeneously high SI (n=49; 62%). On HBP, homogeneous defect were seen in 22 lesions (27.9%), target appearance in five lesions (6.4%), reversed target appearance in two lesions (2.5%), and heterogeneous defect in 50 lesions (63.3%); including reticular (70%), partially globular (26%), and diffuse GGO-like (4%) patterns. According to the imaging features on HBP, the homogeneous defect and heterogeneous defect groups had a mean ADC value of 0.99×10−3 and 1.07×10−3mm2/s, respectively, without statistically significant difference. ConclusionHepatic metastasis from colorectal cancer usually showed as a heterogeneous defect on HBP and a heterogeneous high SI on T2WI. The generally accepted “true defect” was not a common finding in hepatic metastasis from colorectal cancer.