Contrast-enhanced US to Improve Diagnostic Performance of O-RADS US Risk Stratification System for Malignancy.

Background The Ovarian-Adnexal Reporting and Data System (O-RADS) has limited specificity for malignancy. Contrast-enhanced US can help distinguish malignant from benign lesions, but its added value to O-RADS has not yet been assessed. Purpose To establish a diagnostic model combining O-RADS and contrast-enhanced US and to validate whether O-RADS plus contrast-enhanced US has a better diagnostic performance than O-RADS alone. Materials and Methods This prospective study included participants from May 2018 to March 2021 who underwent contrast-enhanced US before surgery and had lesions categorized as O-RADS 3, 4, or 5 by US, with a histopathologic reference standard. From April 2021 to July 2022, participants with pathologically confirmed ovarian-adnexal lesions were recruited for the validation group. In the pilot group, the initial enhancement time and enhancement intensity in comparison with the uterine myometrium, contrast agent distribution pattern, and dynamic changes in enhancement of lesions were assessed. Contrast-enhanced US features were used to calculate contrast-enhanced US scores for benign (score ≤2) and malignant (score ≥4) lesions. Lesions were then re-rated according to O-RADS category plus contrast-enhanced US scores. Receiver operating characteristic curves were constructed and compared using the DeLong method. The combined system was validated in an independent group. Results The pilot group included 76 women (mean age, 44 years ± 13 [SD]), and the validation group included 46 women (mean age, 42 years ± 14). Differences in initial enhancement time (P < .001), enhancement intensity (P < .001), and dynamic changes in enhancement (P < .001) between benign and malignant lesions were observed in the pilot group. Contrast-enhanced US scores were calculated using these features. The O-RADS risk stratification was upgraded one level for contrast-enhanced US scores of 4 or more and downgraded one level for contrast-enhanced US scores of 2 or less. In the validation group, the diagnostic performance of O-RADS plus contrast-enhanced US score was higher (area under the receiver operating characteristic curve [AUC] = 0.93) than O-RADS (AUC = 0.71, P < .001). Conclusion Contrast-enhanced US improved the diagnostic performance for malignancy of the O-RADS categories 3-5. © RSNA, 2023 Supplemental material is available for this article. See also the editorial by Grant in this issue.

Feasibility of Transabdominal Real-time CDFI and HDFI Techniques for Fetal Pulmonary Vein Display in the First Trimester.

OBJECTIVE: This study aimed to assess the feasibility and usefulness of transabdominal color Doppler flow imaging (CDFI) technology and the high-definition flow imaging (HDFI) technique in detecting fetal pulmonary veins (PVs) in the first trimester (11-13+6 weeks). METHODS: From December 2018 to October 2019, 328 pregnant women with 328 normal singleton fetuses (crown-rump length: 45-84 mm) who had undergone CDFI and HDFI scans for fetal heart and vessel examination were enrolled in this study. The cases were divided into three groups according to the gestational age: group A, 11+0 -11+6 weeks; group B, 12+0 -12+6 weeks; and group C, 13+0 -13+6 weeks. Baseline sonograms and CDFI and HDFI images were analyzed by two senior radiologists independently and blindly. The abilities of CDFI and HDFI to display PVs were compared. RESULTS: Successful PV display rates via CDFI and HDFI were 2.3% and 68.2% (P<0.01), 22.4% and 82.4% (P<0.01), 41.5% and 91.2% (P<0.01) for group A, group B, and group C, respectively. The total successful display rates for the two methods were 28.9% (CDFI) and 84.8% (HDFI) (P<0.01). CONCLUSIONS: The HDFI technique is more valuable than CDFI for detecting PVs in early pregnancy (11-13+6 weeks). HDFI can detect at least one PV in all cases and may be used to detect pulmonary venous anomalies early.

Verifier-based anonymous password-authenticated key exchange protocol in the standard model.

Anonymous password-authenticated key exchange (APAKE) allows a client to authenticate herself and to establish a secure session key with a remote server via only a low-entropy password, while keeping her actual identity anonymous to the third party as well as to the server. Since that APAKE protocol enjoys both the convenience of password authentication and the advantage of privacy protection, researchers have paid much attention to them. However, most of the existing APAKE protocols are designed in the symmetric setting which does not take into consideration the threat of password file leakage. To mitigate the damage of server compromise, we propose a verifier-based anonymous password-authenticated key exchange protocol, in which the server holds a verifier corresponding to each client instead of the clear password. The construction of our protocol is built on standard cryptographic primitives such public key encryption, smooth projective hash functions and password hashing schemes. The resulting protocol is proved secure in the standard model, i.e., without resorting to random oracles. Comparisons with other similar schemes show that our protocol guarantees stronger security while enjoys considerable efficiency in terms of computational cost.