A standard calibration method based on a symmetric resistance network matrix for galvanic logging instruments.

An increasing number of measurement electrodes have been designed to satisfy the demand for high-resolution detection using galvanic logging technology in complex formations. The forward modeling response analysis of logging tools has important guiding significance in the design of galvanic logging tools. Based on a three-dimensional finite element numerical simulation method, we established a forward model of galvanic multi-electrodes in a complex formation. We also designed a symmetrical resistance network model of the formation with equivalent resistance between two electrodes. A symmetrical resistance network was derived using the balanced bridge method. The asymmetrical admittance matrix was extended to a symmetrical extended admittance matrix to realize a convenient calculation of the equivalent symmetrical resistance network in complex formations. Verification of the microcolumn-focused logging tool, with nine electrodes in a simulated standard well, and an evaluation of the degree of invasion in an actual oil well indicate that this calibration method can improve the measurement accuracy of galvanic logging instruments.

Multimode Ultrasound Model for Predicting the Early Treatment Response of Anti-VEGF Agents Plus Anti-PD-1 Antibody in Patients with Unresectable Hepatocellular Carcinoma.

OBJECTIVE: The purpose of the study described was to establish prediction models to initially screen the beneficiary patients with unresectable hepatocellular carcinoma (HCC) in the treatment of anti-vascular endothelial growth factor (VEGF) agents plus anti-programmed cell death-1 (PD-1) antibody. METHODS: A total of 62 patients were enrolled in this study. All patients underwent ultrasound (US), color ddoppler flowing imaging (CDFI), contrast-enhanced ultrasound (CEUS) and laboratory examinations within 2 wk before the treatment. Tumor response was assessed according to mRECIST criteria. Univariate and multivariate analyses were used to select the independent predictors. US + CDFI, CEUS and FULL models were established. Three models were displayed by nomography. Receiver operating characteristic (ROC) and calibration curves were drawn to evaluate the predictive ability of models. Decision curve analysis (DCA) was used to assess the clinical utility of models. RESULTS: On univariate and multivariate analysis, the US boundary (p = 0.037), halo (p = 0.002) and CDFI (p = 0.024) were included in the US + CDFI model. CEUS boundary (p = 0.001) and washout time (p < 0.001) were included in the CEUS model. The number of lesions (p = 0.104), halo on US (p = 0.014), CDFI (p = 0.057) and washout time on CEUS (p = 0.015) were incorporated into the FULL model. The C indices of the US + CDFI, CEUS and FULL models were 0.918, 0.920 and 0.973. CEUS and FULL models yielded a good net benefit for almost all threshold probabilities. CONCLUSION: Nomograms based on US, CDFI, CEUS and clinical characteristics could help to non-invasively predict the response to treatment with anti-PD-1 antibodies plus anti-VEGF agents.

Preoperative supine time for adrenal venous sampling: a prospective randomized controlled trial.

BACKGROUND: Primary aldosteronism (P.A.) is the most common form of secondary hypertension, accounting for 5% of hypertensive patients and 17-23% of patients with resistant hypertension. Compared to primary hypertension, P.A. is more prone to cause severe organ damage and even early death. Adrenal venous sampling (AVS) is a practical confirmatory test for subtyping aldosterone-producing adenoma and bilateral adrenal hyperplasia, helping physicians to make an accurate decision between surgery or medication. According to guidelines, supine in bed before AVS is recommended for a desirable result of AVS. However, investigations about the most optimal preoperative supine time before AVS are lacking. METHODS/DESIGN: This is a multi-center prospective randomized controlled study. One hundred twenty patients diagnosed as P.A. and willing for AVS examination will be included. Participants will be randomly allocated to a 15-min supine time group or 2-h supine time group. The primary outcome is the degree of biochemical remission (serum potassium and orthostatic ARR). The secondary outcomes are degrees of clinical remission (blood pressure, type and dose of antihypertensive drugs), the technical success rate, and the adverse event of AVS (selective index ≥ 2 is considered successful surgery without corticotropin stimulation). DISCUSSION: P.A. is an intractable public health problem, and many techniques including AVS have been developed to identify this disease correctly. This study will help to understand whether the length of preoperative supine time would affect the diagnostic efficacy of AVS and thus help to formulate a more reasonable AVS procedure. TRIAL REGISTRATION: ClinicalTrials.gov NCT05658705. Registered on 10 September 2022.