A new computational fluid dynamics based noninvasive assessment of portacaval pressure gradient.

Accurate assessment of portacaval pressure gradient (PCG) in patients with portal hypertension (PH) is of great significance both for diagnosis and treatment. This study aims to develop a noninvasive method for assessing PCG in PH patients and evaluate its accuracy and effectiveness. This study recruited 37 PH patients treated with transjugular intrahepatic portosystemic shunt (TIPS). computed tomography angiography was used to create three dimension (3D) models of each patient before and after TIPS. Doppler ultrasound examinations were conducted to obtain the patient's portal vein flow (or splenic vein and superior mesenteric vein). Using computational fluid dynamics (CFD) simulation, the patient's pre-TIPS and post-TIPS PCG was determined by the 3D models and ultrasound measurements. The accuracy of these noninvasive results was then compared to clinical invasive measurements. The results showed a strong linear correlation between the PCG simulated by CFD and the clinical invasive measurements both before and after TIPS (R2 = 0.998, P < 0.001 and R2 = 0.959, P < 0.001). The evaluation accuracy of this noninvasive method reached 94 %, and the influence of ultrasound result errors on the numerical accuracy was found to be marginal if the error was less than 20 %. Furthermore, the information about the hemodynamic environment in the portal system was obtained by this numerical method. Spiral flow patterns were observed in the portal vein of some patients. In a conclusion, this study proposes a noninvasive numerical method for assessing PCG in PH patients before and after TIPS. This method can assist doctors in accurately diagnosing patients and selecting appropriate treatment plans. Additionally, it can be used to further investigate potential biomechanical causes of complications related to TIPS in the future.

Assessment of biopsy proven liver fibrosis by two-dimensional shear wave elastography in patients with primary biliary cholangitis.

BACKGROUND: Two-dimensional shear-wave elastography (2D-SWE) is an ultrasound-based technique used to stage liver fibrosis by measuring liver stiffness (LS). The diagnostic performance of 2D-SWE for assessing liver fibrosis in patients with primary biliary cholangitis (PBC) has not been reported before. AIMS: To investigate the diagnostic performance of 2D-SWE for staging liver fibrosis in patients with PBC by using histologic analysis as a reference standard. METHODS: Patients with PBC who underwent liver biopsy and 2D-SWE were retrospectively collected. Liver fibrosis was staged according to the Scheuer scoring system. Areas under receiver operating characteristic curve (AUROC) was constructed to assess the accuracy of 2D-SWE and serum fibrosis models for staging liver fibrosis. RESULTS: The diagnostic performance characteristics were determined for 157 patients with PBC. The AUROCs of LS measured by 2D-SWE for significant fibrosis, severe fibrosis, and cirrhosis were 0.88, 0.97 and 0.99, respectively. The cutoff values of LS measured by 2D-SWE in discriminating significant fibrosis, severe fibrosis, and cirrhosis were 10.7 kPa, 12.2 kPa and 14.1 kPa, respectively. The diagnostic accuracy of 2D-SWE for staging liver fibrosis was 73.9%. CONCLUSIONS: 2D-SWE is an efficient noninvasive method for the assessment of liver fibrosis in patients with PBC.

Virtual laryngoscopy: a noninvasive tool for the assessment of laryngeal tumor extent.

OBJECTIVES: Present a clinical application of virtual laryngoscopy (VL) in the assessment of laryngeal tumor and its extent. STUDY DESIGN: CT data from two subjects are acquired for this preliminary study. One subject is a healthy volunteer and the other is a patient with laryngeal tumor. The laryngeal framework and upper airway are reconstructed using CT data, which allows for computer-aided internal and external anatomical views and interactive fly-through. METHODS: These CT data are reconstructed into 0.5 mm slice images, resulting in a total of 200-300 image slices. An advanced commercial visualization software (AMIRA) is used for 3D image segmentation, reconstruction and surface rendering of laryngeal anatomical structures. RESULTS: The 3D laryngeal framework and upper airway are reconstructed for both the tumor patient and the healthy subject. The conventional views of the reconstructed vocal folds are compared with those obtained from fiber-optic laryngoscope. Additionally, unique views of the vocal folds obtained from retrograde visualization and fly-through are presented, which are not possible to obtain using conventional endoscope imaging. The segmented anatomical model and the tumor from the patient's CT images were displayed individually to show the distribution of the tumor and its extent as well as spatial and contextual relationships to the larynx and airway anatomical structures. CONCLUSIONS: This study demonstrated the potential application of VL as a noninvasive clinical diagnostic tool for the assessment of laryngeal tumor and its extent. Our preliminary results demonstrated that the VL may provide valuable insights for the diagnosis and treatment planning for laryngeal and airway tumors. The noninvasive VL may complement the invasive laryngoscopic examinations for the staging of tumors and follow-ups on surgical interventions.