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Cardiovascular system
Published in A Stewart Whitley, Jan Dodgeon, Angela Meadows, Jane Cullingworth, Ken Holmes, Marcus Jackson, Graham Hoadley, Randeep Kumar Kulshrestha, Clark’s Procedures in Diagnostic Imaging: A System-Based Approach, 2020
A Stewart Whitley, Jan Dodgeon, Angela Meadows, Jane Cullingworth, Ken Holmes, Marcus Jackson, Graham Hoadley, Randeep Kumar Kulshrestha
As mentioned above, the primary imaging modalities for the assessment of the lower limb venous system are ultrasound and MR venography. Formal venography is generally performed to answer specific questions raised by these former investigations or if they are not available: Diagnosis and assessment of DVT.Assess patency of deep veins prior to varicose vein surgery.Assessment of varicose veins for the detection of incompetent perforating veins and incompetent venous valves.Congenital vascular malformations involving the venous system.
Numerical investigation of multi-pulsed cryogen spray cooling for skin cold protection in laser lipolysis
Published in Numerical Heat Transfer, Part A: Applications, 2020
Hui Xin, Bin Chen, Zhifu Zhou, Dong Li, Jiameng Tian
Existing simulations on MCS in laser surgery have focused on the treatment of port wine stain (PWS), which is a congenital vascular malformation existing in the dermis [23]. During laser PWS simulation, the skin can be simplified as a multilayer homogeneous model [18], discrete blood vessel model [24], or porous medium model [23]. To overcome the insufficient cold protection of a single cryogen spray for darkly pigmented skin type (e.g., V–VI types [25]), Aguilar et al. [26] developed a four-layer homogenous model to calculate the heat diffusion and light distribution. The findings showed that multiple cryogen spurts and multiple laser pulses (MCS-MLP) can produce expected destruction to PWS and provide sufficient epidermal cold protection of the types V–VI skin. Large diameter vessels can be partially coagulated and subsequently recanalized because laser energy may be absorbed by melanin. Jia et al. [27] presented a novel therapy of intermittent multiple cryogen spurts with multiple two-wavelength laser pulses (MCS-MTWLP). The numerical simulation indicated that MCS-MTWLP can achieve the photocoagulation of large-diameter vessels and provide sufficient epidermal cold protection compared with single cryogen spurt and single laser pulse. Chen et al. [28] simulated energy deposition and temperature distribution of 1064 nm (1210 nm) laser in biological tissues and observed that 1064 nm (1210 nm) laser radiation can effectively destroy adipocytes.