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The aim of the study was to investigate the value of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and intravoxel incoherent motion (IVIM) in differentiating TP53-mutant from wild type, low-risk from non-low-risk early-stage endometrial carcinoma (EC).

Acute kidney injury (AKI) is a frequent complication of critical illness and carries a significant risk of short‐ and long‐term mortality. The prediction of the progression of AKI to long‐term injury has been difficult for renal disease treatment. Radiologists are keen for the early detection of transition from AKI to long‐term kidney injury, which would help in the preventive measures. The lack of established methods for early detection of long‐term kidney injury underscores the pressing needs of advanced imaging technology that reveals microscopic tissue alterations during the progression of AKI. Fueled by recent advances in data acquisition and post‐processing methods of magnetic resonance imaging (MRI), multiparametric MRI is showing great potential as a diagnostic tool for many kidney diseases. Multiparametric MRI studies offer a precious opportunity for real‐time noninvasive monitoring of pathological development and progression of AKI to long‐term injury. It provides insight into renal vasculature and function (arterial spin labeling, intravoxel incoherent motion), tissue oxygenation (blood oxygen level‐dependent), tissue injury and fibrosis (diffusion tensor imaging, diffusion kurtosis imaging, T1 and T2 mapping, quantitative susceptibility mapping). The multiparametric MRI approach is highly promising but the longitudinal investigation on the transition of AKI to irreversible long‐term impairment is largely ignored. Further optimization and implementation of renal MR methods in clinical practice will enhance our comprehension of not only AKI but chronic kidney diseases. Novel imaging biomarkers for microscopic renal tissue alterations could be discovered and benefit the preventative interventions. This review explores recent MRI applications on acute and long‐term kidney injury while addressing lingering challenges, with emphasis on the potential value of the development of multiparametric MRI for renal imaging on clinical systems. Evidence Level: 1 Technical Efficacy: Stage 2 [ABSTRACT FROM AUTHOR]

Introduction: The GLP-1 receptor plays an important role in glucose homeostasis and thus is a very important target for diabetes therapy. The receptor is also overexpressed in insulinoma, a tumor of pancreatic beta-cells. We previously evaluated two fluorine-18-labeled analogs of exendin-4 prepared by conjugation with [18F]FBEM (N-[2-(4-[18F]fluorobenzamide)ethyl]maleimide). Both compounds demonstrated good tumor uptake, but the synthesis of the radiotracers was time consuming. To overcome this challenge, we developed a NOTA analog and performed radiolabeling using aluminum [18F]fluoride complexation.Methods: Cys40-exendin-4 was conjugated with NOTA mono N-ethylmaleimide. [18F]AlF conjugation was conducted and the radiolabeled product purified by preparative HPLC. Dynamic and static PET imaging scans were conducted on nude mice with established INS-1 xenografts. Uptake of tumor and other major organs in static images was quantitated (%ID/g) and comparison with blocking studies was made. PET quantification was also compared with ex vivo biodistribution results.Results: The radiosynthesis provided [18F]AlF-NOTA-MAL-cys40-exendin-4 in 23.6 ± 2.4 % radiochemical yield (uncorrected, n = 3) after HPLC; the process required about 55 min. The specific activity at time of injection ranged from 19.6 to 31.4 GBq (0.53-0.85 Ci)/µmol. Tumor uptake had reached its maximum (16.09 ± 1.18% ID/g, n = 4) by 5 min and remained nearly constant for the duration of the study. Kidney uptake continued to increase throughout the entire one hour time course. Pre-injection of exendin-4 caused a marked reduction in tissue uptake with the major exception of liver and kidneys, in which uptake was not affected. HPLC analysis of the radioactive components in extracts of the tumor and plasma showed primarily parent compound at 60 min post-injection, whereas extracts of kidney and urine contained exclusively one polar radioactive component.Conclusion: The radiotracer is prepared in a simple one-step procedure and obtained in high specific activity after HPLC purification. [18F]AlF-NOTA-MAL-exendin-4 shows high tumor uptake and highly selective GLP-1 tissue uptake (INS-1 tumor, lung, pancreas), but still suffers from high kidney uptake.

Background: Breast cancer is the most common malignant tumor in women and a quantitative contrast‐free method is highly desirable for its diagnosis. Purpose: To investigate the performance of quantitative MRI in differentiating malignant from benign breast lesions and to compare with the Breast Imaging Reporting and Data System (BI‐RADS). Study Type: Retrospective. Subjects: Eighty patients (56 with malignant lesions and 24 with benign lesions). Field Strength/Sequence: Diffusion‐weighted imaging (DWI) with a single‐shot echo planar sequence and synthetic MRI with magnetic resonance image compilation (MAGiC) were performed at 3T. Assessment: T1 relaxation time (T1), T2 relaxation time (T2), and proton density (PD) from synthetic MRI and apparent diffusion coefficient (ADC) from DWI were analyzed by two radiologists (Reader A, Reader B). Univariable and multivariable models were developed to optimize differentiation between malignant and benign lesions and their performances compared to BI‐RADS. Statistical Tests: The diagnostic performance was evaluated using multivariate logistic regression analysis and area under the receiver operating characteristic (ROC) curves (AUC). Results: T2, PD, and ADC values for malignant lesions were significantly lower than those in benign breast lesions for both radiologists (all P < 0.05). The combined T2, PD, and ADC model had the best performance for differentiating malignant and benign lesions with AUC, sensitivity, specificity, positive predictive value, and negative predictive values of 0.904, 94.6%, 87.5%, 94.6%, and 87.5%, respectively. The corresponding results for BI‐RADS were no AUC, 94.6%, 75.0%, 89.8%, and 85.7%, respectively. Data Conclusion: The approach that combined synthetic MRI and DWI outperformed BI‐RADS in the differential diagnosis of malignant and benign breast lesions and was achieved without contrast agents. This approach may serve as an alternative and effective strategy for the improvement of breast lesion differentiation. Level of Evidence: 3. Technical Efficacy Stage: 3. [ABSTRACT FROM AUTHOR]