[Efficacy of endovascular treatment of distal aortic dissection involving abdominal visceral segment with bare-metal stents related technique].

Objective: To investigate the effect of bare-metal stent related technique on distal aortic dissection involving abdominal visceral segment. Methods: A retrospective analysis was performed on clinical data of 33 patients with distal aortic dissection involved abdominal visceral segment, who hospitalized in the Vascular Surgery Department of Shanghai Changhai Hospital from July 2012 to September 2019. The effect of the treatment was evaluated according to the clinical and preoperative, intraoperative and follow-up imaging data derived from (aorta computed tomography angiography (CTA) and digital subtraction angiography (DSA)) as well as the changes of the maximal diameter of the aorta and the thrombosis of the false lumen of the dissection. The criteria were as follows: the maximum diameter change of aortic dissection<5 mm was defined as stable; the maximum diameter decrease of aortic dissection≥5 mm was defined as effective reduction; the maximum diameter increase of aortic dissection≥5 mm was defined as expansion; the definition of diameter change of false lumen was the same as above. The hospital complications, clinical symptoms and survival were recorded. Results: There were 28 male patients in this cohort, the mean age was (57.6±4.9) years old. Twenty-one patients were treated with bare-metal stent and coils technique, of which 8 patients were jointly treated with stent grafts. Twelve patients were treated with multi-layer bare-metal stent technique, of which 4 patients were jointly treated with stent grafts. Intraoperative DSA image results showed that the visceral arteries were patent during the treatment, and the blood flow velocity of the false lumen was reduced in all 33 patients. There were no adverse events such as distal outflow tract embolism and coil displacement during the operation. During the period of hospitalization, one patient developed intimal rupture of subrenal abdominal aortic dissection on the fourth day after operation and emergency endovascular graft exclusion was performed for abdominal aortic dissection, and the patient recovered well from the emergency operation. The follow-up time was (16.7±14.0) months. One patient died 1 year after surgery due to non-disease-related factors. Follow-up CTA imaging results showed that the maximum diameter of the aorta in abdominal visceral segment tended to be smaller ((39.1±13.4) mm vs. (41.3±11.9) mm, P=0.469), and the maximum diameter of the false lumen was significantly reduced ((16.2±12.9) mm vs. (23.5±10.7) mm, P=0.014). The maximum diameter of the aortic dissection was reduced in 12 cases, stable in 19 cases, expanded in 2 cases. The maximum diameter of the false lumen was effectively reduced in 22 cases, stable in 10 cases, and expanded in 1 case. Four patients developed small endoleak in the false lumen, one of them was nearby the renal artery stent, and the remaining patients experienced complete thrombosis of the false lumen. Conclusions: Endovascular treatment of distal aortic dissection involving abdominal visceral segment with bare-metal stents related technique could promote the shrink and the thrombosis of the false lumen, and slow down the blood flow from the tear into the false lumen in the setting of patency of visceral arteries.

Development of an integrated energetic neutral particle measurement system on experimental advanced full superconducting tokamak.

Full function integrated, compact silicon photodiode based solid state neutral particle analyzers (ssNPA) have been developed for energetic particle (EP) relevant studies on the Experimental Advanced Superconducting Tokamak (EAST). The ssNPAs will be mostly operated in advanced current mode with a few channels to be operated in conventional pulse-counting mode, aiming to simultaneously achieve individually proved ultra-fast temporal, spatial, and spectral resolution capabilities. The design details together with considerations on EAST specific engineering realities and physics requirements are presented. The system, including a group of single detectors on two vertical ports and two 16-channel arrays on a horizontal port, can provide both active and passive charge exchange measurements. ssNPA detectors, with variable thickness of ultra thin tungsten dominated foils directly deposited on the front surface, are specially fabricated and utilized to achieve about 22 keV energy resolution for deuterium particle detection.

New dual gas puff imaging system with up-down symmetry on experimental advanced superconducting tokamak.

Gas puff imaging (GPI) offers a direct and effective diagnostic to measure the edge turbulence structure and velocity in the edge plasma, which closely relates to edge transport and instability in tokamaks. A dual GPI diagnostic system has been installed on the low field side on experimental advanced superconducting tokamak (EAST). The two views are up-down symmetric about the midplane and separated by a toroidal angle of 66.6°. A linear manifold with 16 holes apart by 10 mm is used to form helium gas cloud at the 130×130 mm (radial versus poloidal) objective plane. A fast camera is used to capture the light emission from the image plane with a speed up to 390,804 frames/s with 64×64 pixels and an exposure time of 2.156 µs. The spatial resolution of the system is 2 mm at the objective plane. A total amount of 200 Pa.L helium gas is puffed into the plasma edge for each GPI viewing region for about 250 ms. The new GPI diagnostic has been applied on EAST for the first time during the recent experimental campaign under various plasma conditions, including ohmic, L-mode, and type-I, and type-III ELMy H-modes. Some of these initial experimental results are also presented.