Radiomics nomogram for prediction of glypican-3 positive hepatocellular carcinoma based on hepatobiliary phase imaging

IntroductionThe hepatobiliary-specific phase can help in early detection of changes in lesion tissue density, internal structure, and microcirculatory perfusion at the microscopic level and has important clinical value in hepatocellular carcinoma (HCC). Therefore, this study aimed to construct a preoperative nomogram for predicting the positive expression of glypican-3 (GPC3) based on gadoxetic acid-enhanced (Gd-EOB-DTPA) MRI hepatobiliary phase (HBP) radiomics, imaging and clinical feature.MethodsWe retrospectively included 137 patients with HCC who underwent Gd-EOB-DTPA-enhanced MRI and subsequent liver resection or puncture biopsy at our hospital from January 2017 to December 2021 as training cohort. Subsequently collected from January 2022 to June 2023 as a validation cohort of 49 patients, Radiomic features were extracted from the entire tumor region during the HBP using 3D Slicer software and screened using a t-test and least absolute shrinkage selection operator algorithm (LASSO). Then, these features were used to construct a radiomics score (Radscore) for each patient, which was combined with clinical factors and imaging features of the HBP to construct a logistic regression model and subsequent nomogram model. The clinicoradiologic, radiomics and nomogram models performance was assessed by the area under the curve (AUC), calibration, and decision curve analysis (DCA). In the validation cohort,the nomogram performance was assessed by the area under the curve (AUC).ResultsIn the training cohort, a total of 1688 radiomics features were extracted from each patient. Next, radiomics with ICCs<0.75 were excluded, 1587 features were judged as stable using intra- and inter-class correlation coefficients (ICCs), 26 features were subsequently screened using the t-test, and 11 radiomics features were finally screened using LASSO. The nomogram combining Radscore, age, serum alpha-fetoprotein (AFP) >400ng/mL, and non-smooth tumor margin (AUC=0.888, sensitivity 77.7%, specificity 91.2%) was superior to the radiomics (AUC=0.822, sensitivity 81.6%, specificity 70.6%) and clinicoradiologic (AUC=0.746, sensitivity 76.7%, specificity 64.7%) models, with good consistency in calibration curves. DCA also showed that the nomogram had the highest net clinical benefit for predicting GPC3 expression.In the validation cohort, the ROC curve results showed predicted GPC3-positive expression nomogram model AUC, sensitivity, and specificity of 0.800, 58.5%, and 100.0%, respectively.ConclusionHBP radiomics features are closely associated with GPC3-positive expression, and combined clinicoradiologic factors and radiomics features nomogram may provide an effective way to non-invasively and individually screen patients with GPC3-positive HCC

X-ray dose reduction in abdominal computed tomography using advanced iterative reconstruction algorithms.

OBJECTIVE: This work aims to explore the effects of adaptive statistical iterative reconstruction (ASiR) and model-based iterative reconstruction (MBIR) algorithms in reducing computed tomography (CT) radiation dosages in abdominal imaging. METHODS: CT scans on a standard male phantom were performed at different tube currents. Images at the different tube currents were reconstructed with the filtered back-projection (FBP), 50% ASiR and MBIR algorithms and compared. The CT value, image noise and contrast-to-noise ratios (CNRs) of the reconstructed abdominal images were measured. Volumetric CT dose indexes (CTDIvol) were recorded. RESULTS: At different tube currents, 50% ASiR and MBIR significantly reduced image noise and increased the CNR when compared with FBP. The minimal tube current values required by FBP, 50% ASiR, and MBIR to achieve acceptable image quality using this phantom were 200, 140, and 80 mA, respectively. At the identical image quality, 50% ASiR and MBIR reduced the radiation dose by 35.9% and 59.9% respectively when compared with FBP. CONCLUSIONS: Advanced iterative reconstruction techniques are able to reduce image noise and increase image CNRs. Compared with FBP, 50% ASiR and MBIR reduced radiation doses by 35.9% and 59.9%, respectively

The cross section of the phantom.

<p>It has circular holes (arrows) to place the radiation dose meter. We evaluated the image quality about display of the circular hole (for placing a radiation dose meter) and the boundary of the image.</p

Image noise analysis based on the different reconstruction models.

<p>The schematic diagram of SD and CNR variations according to the mA values. All three reconstruction algorithms showed increased noise as the tube current decreased: FBP presented the most noticeable variations, followed by 50% ASiR and then by MBIR; the three models showed decreased CNRs as the tube current decreased, but at the same tube current, MBIR presented the highest CNR, which was followed by 50% ASiR and then by FBP.</p

The cross section of the phantom.

<p>It has circular holes (arrows) to place the radiation dose meter. We evaluated the image quality about display of the circular hole (for placing a radiation dose meter) and the boundary of the image.</p

The schematic diagram of the SD decrease and CNR increase rates by 50% ASiR and MBIR (compared with those by FBP).

<p>As the mA value decreased, MBIR brought about gradually augmented variations in the two parameters, whereas 50% ASiR did not give rise to noticeable variations.</p

The schematic diagram of CTDIvol variations according to the mA value.

<p>CTDIvol decreases as the mA value decreases.</p

Comparison study of hot deformation behavior and processing map of AZ80 magnesium alloy casted with and without ultrasonic vibration

In order to compare the workability of AZ80 magnesium alloy casted with and without variablefrequency ultrasonic field (VUF), uniaxial hot compression tests were carried out in the temperature range of 523-673 K and the strain rate range of 0.001-1 s(-1) on a Gleeble-3500D thermo-mechanical simulator. The flow stress, constitutive relation, DRX kinetic model and processing map were analyzed based on the experimental data. The results show that, the VUF samples have lower peak stress and peak strain than DC samples at low strain rates, while the opposite situation can be observed at high strain rate. The calculated activation energy Q and stress exponent n for DC samples are 192.38 kJ/mol and 7.30158, which are higher than the calculated values for VUF samples, showing the figures of 165.30 kJ/mol and 7.30158, respectively. The VUF casted samples start DRX earlier and easier, and can obtain complete DRX structure at high strain rate. The VUF samples have larger workability range but smaller instability region than DC samples. Dense and irregular bulges can be observed on side surfaces of DC samples after compression, while surfaces of VUF samples are smooth. (C) 2019 Elsevier B.V. All rights reserved