Direct Multi-Material Reconstruction via Iterative Proximal Adaptive Descent for Spectral CT Imaging.

Spectral computed tomography (spectral CT) is a promising medical imaging technology because of its ability to provide information on material characterization and quantification. However, with an increasing number of basis materials, the nonlinearity of measurements causes difficulty in decomposition. In addition, noise amplification and beam hardening further reduce image quality. Thus, improving the accuracy of material decomposition while suppressing noise is pivotal for spectral CT imaging. This paper proposes a one-step multi-material reconstruction model as well as an iterative proximal adaptive decent method. In this approach, a proximal step and a descent step with adaptive step size are designed under the forward-backward splitting framework. The convergence analysis of the algorithm is further discussed according to the convexity of the optimization objective function. For simulation experiments with different noise levels, the peak signal-to-noise ratio (PSNR) obtained by the proposed method increases approximately 23 dB, 14 dB, and 4 dB compared to those of other algorithms. Magnified areas of thorax data further demonstrated that the proposed method has a better ability to preserve details in tissues, bones, and lungs. Numerical experiments verify that the proposed method efficiently reconstructed the material maps, and reduced noise and beam hardening artifacts compared with the state-of-the-art methods.

The diagnosis and management of psoriasis patients under the outbreak of the new coronavirus pneumonia epidemic

The novel coronavirus pneumonia outbreak was seriously and showed a rapid spread of the transmission on December 2019. All parts of the country have been actively raising medical resources and methodically preventing and controlling the epidemic. In this particular situation, the control and follow-up of patients with chronic skin conditions, especially psoriasis patients need constant guidance and treatment. In addition, most patients have impaired skin barrier function, and the improper protection may increase susceptibility to the virus. Due to the need of prevention and control, travel restrictions initiative increased the mental tension, and the anxiety, depression and other psychological reactions from the psoriasis may further produce emotional tension and thus aggravate the disease. Therefore, guidance of uninterrupted effective treatment, establishing a good state of mind, maintaining patients' personal health and treatment, and improving the quality of life are important under the special occasion.