Intentionally unilateral prostatic artery embolization:Patient selection,technique and potential benefits

BACKGROUND Prostatic artery embolization(PAE)is a promising but also technically demanding interventional radiologic treatment for symptomatic benign prostatic hyperplasia.Many technical challenges in PAE are associated with the complex anatomy of prostatic arteries(PAs)and with the systematic attempts to catheterize the PAs of both pelvic sides.Long procedure times and high radiation doses are often the result of these attempts and are considered significant disadvantages of PAE.The authors hypothesized that,in selected patients,these disadvantages could be mitigated by intentionally embolizing PAs of only one pelvic side.AIM To describe the authors’approach for intentionally unilateral PAE(IU-PAE)and its potential benefits.METHODS This was a single-center retrospective study of patients treated with IU-PAE during a period of 2 years.IU-PAE was applied in patients with opacification of more than half of the contralateral prostatic lobe after angiography of the ipsilateral PA(subgroup A),or with markedly asymmetric prostatic enlargement,with the dominant prostatic lobe occupying at least two thirds of the entire gland(subgroup B).All patients treated with IU-PAE also fulfilled at least one of the following criteria:Severe tortuosity or severe atheromatosis of the pelvic arteries,non-visualization,or visualization of a tiny(<1 mm)contralateral PA on preprocedural computed tomographic angiography.Intraprocedural contrast-enhanced ultrasonography(iCEUS)was applied to monitor prostatic infarction.IU-PAE patients were compared to a control group treated with bilateral PAE.RESULTS IU-PAE was performed in a total 13 patients(subgroup A,n=7;subgroup B,n=6).Dose-area product,fluoroscopy time and operation time in the IU-PAE group(9767.8μGy∙m^(2),30.3 minutes,64.0 minutes,respectively)were significantly shorter(45.4%,35.9%,45.8%respectively,P<0.01)compared to the control group.Clinical and imaging outcomes did not differ significantly between the IU-PAE group and the control group.In the 2 clinical failures of IU-PAE(both in subgroup A),the extent of prostatic infarction(demonstrated by iCEUS)was significantly smaller compared to the rest of the IU-PAE group.CONCLUSION In selected patients,IU-PAE is associated with comparable outcomes,but with lower radiation exposure and a shorter procedure compared to bilateral PAE.iCEUS could facilitate patient selection for IU-PAE.

Tomographical evidence for Indian Plate underthrusting only beneath Tethyan Himalaya

Tomographical inversion was performed using the data recorded by 51 seismographys deployed on a profile that followed southern Xizang (Tibet) high-way through a Sino-French Joint seismic experiment. The results indicate that the underthrusting Indian Plate is limited to the south of IndusYarlung Zangbo Suture (IYS) beneath Tethyan Himalaya, extends vertically to 150 km deep with relatively high angle near Gala, and becomes horizontally northward. The seismic velocities beneath Kangmar, Gangdise and Yangbajain-Golug rift in the middle of the lithosphere show low velocity features, which may indicate the existence of high temperature and partial melting. The results from tomography strongly suggest that the continent-continent subduction occurred only beneath Himalaya and was confined to the south of IYS since the collision between India and Eurasia.

Ultra-fast 3D printing of assembly——free complex optics with sub-nanometer surface quality at mesoscale

Complex-shaped optical lenses are of great interest in the areas of laser processing,machine vision,and optical communications.Traditionally,the processing of complex optical lenses is usually achieved by precision machining combined with post-grinding or polishing,which is expensive,labor-intensive and difficult in the processing of ultra-complex optical lenses.Additive manufacturing is an emerging technology that provides significant advantages in producing highly intricate optical devices.However,the layer-by-layer method employed in such manufacturing processes has resulted in low printing speeds,as well as limitations in surface quality.To address these challenges,we apply tomographic volumetric printing(TVP)in this work,which can realize the integrated printing of complex structural models without layering.By coordinating the TVP and the meniscus equilibrium post-curing methods,ultra-fast fabrication of complex-shaped lenses with sub-nanometric roughness has been achieved.A2.5 mm high,outer diameter 9 mm spherical lens with a roughness value of RMS=0.3340 nm is printed at a speed of 3.1×10^(4)mm^(3)h^(-1).As a further demonstration,a complex-shaped fly-eye lens is fabricated without any part assembly.The designed spherical lens is mounted on a smartphone’s camera,and the precise alignments above the circuit board are captured.Upon further optimization,this new technology demonstrates the potential for rapid fabrication of ultra-smooth complex optical devices or systems.

Tomographic inversion of near-surface Q factor by combining surface and cross-hole seismic surveys

The estimation of the quality factor Q plays a fundamental role in enhancing seismic resolution via absorption compensation in the near-surface layer.We present a new geometry that can be used to acquire field data by combining surface and cross-hole surveys to decrease the effect of geophone coupling on Q estimation.In this study,we drilled number of receiver holes around the source hole,each hole has different depth and each geophone is placed geophones into the bottom of each receiver hole to avoid the effect of geophone coupling with the borehole wall on Q estimation in conventional cross-hole seismic surveys.We also propose a novel tomographic inversion of the Q factor without the effect of the source signature,and examine its stability and reliability using synthetic data.We estimate the Q factors of the near-surface layer in two different frequency bands using field data acquired in the Dagang Oilfield.The results show that seismic absorption in the nearsurface layer is much greater than that in the subsurface strata.Thus,it is of critical practical importance to enhance the seismic solution by compensating for near-surface absorption.In addition,we derive different Q factors from two frequency bands,which can be treated,to some extent,as evidence of a frequency-dependent Q.

Tomographic inversion for microseismic source parameters in mining

We propose a new method for inverting source function of microseismic event induced in mining. The observed data from microseismic monitoring during mining are represented by a wave equation in a spherical coordinate system and then the data are transformed from the time-space domain to the time-slowness domain based on tomographic principle, from whichwe can obtain the signals related to the source in the time-slowness domain. Through analyzing the relationship between the signal located at the maximum energy and the source function, we derive the tomographic equations to compute the source function from the signals and to calculate the effective radiated energy based on the source function. Moreover, we fit the real amplitude spectrum of the source function computed from the observed data into the co-2 model based on the least squares principle and determine the zero-frequency level spectrum and the corner frequency, finally, the source rupture radius of the event is calculated and The synthetic and field examples demonstrate that the proposed tomographic inversion methods are reliable and efficient

Wave equation tomographic velocity inversion method based on the Born/Rytov approximation

This paper discusses Born/Rytov approximation tomographic velocity inversion methods constrained by the Fresnel zone. Calculations of the sensitivity kernel function and traveltime residuals are critical in tomographic velocity inversion. Based on the Bom/Rytov approximation of the frequency-domain wave equation, we derive the traveltime sensitivity kemels of the wave equation on the band-limited wave field and simultaneously obtain the traveltime residuals based on the Rytov approximation. In contrast to single-ray tomography, the modified velocity inversion method improves the inversion stability. Tests of the near- surface velocity model and field data prove that the proposed method has higher accuracy and Computational efficiency than ray theory tomography and full waveform inversion methods.

Tomographic velocity inversion for ADCIGs in areas with a rugged surface

Pre-stack depth migration velocity analysis is one of the key techniques influencing image quality. As for areas with a rugged surface and complex subsurface, conventional prestack depth migration velocity analysis corrects the rugged surface to a known datum or designed surface velocity model on which to perform migration and update the velocity. We propose a rugged surface tomographic velocity inversion method based on angle-domain common image gathers by which the velocity field can be updated directly from the rugged surface without static correction for pre-stack data and improve inversion precision and efficiency. First, we introduce a method to acquire angle-domain common image gathers （ADCIGs） in rugged surface areas and then perform rugged surface tornographic velocity inversion. Tests with model and field data prove the method to be correct and effective.

Tomographic Principle of Multiconjugate Correction in Adaptive Optics

A wavefront sensing and correction correction is proposed that would allow the field of view (FOV) of an adaptive optics spstem to be increased in size by a factor of several tens. This concept is based on the idea of placing multiple deformable mirrors (DMs) at locations that are conjugate to corresponding. layers of atmospheric turbulence. In order to control properly each DM, a tomographic method for determining the phase distortion contributed by each atmospheric layer has been developed and used in dealing with the circumstance of two layers.

Treatment of Non-Small Cell Lung Cancer (NSCLC) Using CT in Combination with a PET Examination to Minimize the Clinical Target Volume of the Mediastinum

OBJECTIVE To decrease radiation injury of the esophagus and lungs by utilizing a CT scan in combination with PET tumor imaging in order to minimize the clinical target area of locally advanced non-small cell lung can-cer, without preventive radiation on the lymphatic drainage area. METHODS Of 76 patients with locally advanced non-small cell lung cancer (NSCLC), 32 received a PET examination before radiotherapy. Preventive radiation was not conducted in the mediastinum area without lymphatic metastasis, which was confirmed by CT and PET. For the other 44 patients, preventive radiation was performed in the lymphatic drainage area. PET examinations showed that the clinical target volume of the patients was decreased on average to about one third. The radiation therapy for patients of the two groups was the same, i.e. the dose for accelerated fractionated irradiation was 3 Gy/time and 5 time/week. The preventive dose was 42 to 45 Gy/time, 14 to 15 time/week, with 3-week treatment, and the therapeu- tic dose was 60 to 63 Gy/time, 20 to 21 time/week, with a period of 4 to 5 weeks. RESULTS The rate of missed lymph nodes beyond the irradiation field was 6.3% and 4.5% respectively in the group with and without PET exami- nation (P = 0.831). The incidence of acute radioactive esophagitis was 15.6 % and 45.5% in the two groups respectively (P = 0.006). The incidence of acute radiation pneumonia and long-term pulmonary fibrosis in the two groups was 6.3% and 9.1%, and 68.8% and 75.0%, respectively (P = 0.982 and P = 0.547). CONCLUSION The recurrence rate in the lymph nodes beyond the tar-get area was not increased after minimizing the clinical target volume (CTV), whereas radioactive injury to the lungs and esophageal injury was reduced, and especially with a significant decrease in the rate of acute radioactive esophagitis. The method of CT in combination with PET for minimizing the mediastinal CTV is superior to the conventional preventive radiation of the mediastinum.

Automatically positioning microseismic sources in mining by the stereo tomographic method using full wavefields

For microseisimic monitoring it is difficult to determine wave modes and their propagation velocity. In this paper, we propose a new method for automatically inverting in real time the source characteristics of microseismic events in mine engineering without wave mode identification and velocities. Based on the wave equation in a spherical coordinate system, we derive a tomographic imaging equation and formulate a scanning parameter selection criterion by which the microseisimic event maximum energy and corresponding parameters can be determined. By determining the maximum energy positions inside a given risk district, we can indentify microseismic events inside or outside the risk districts. The synthetic and field examples demonstrate that the proposed tomographic imaging method can automatically position microseismic events by only knowing the risk district dimensions and range of velocities without identifying the wavefield modes and accurate velocities. Therefore, the new method utilizes the full wavefields to automatically monitor microseismic events.

Differentiating Crohn's disease from intestinal tuberculosis

Differentiating Crohn's disease(CD) and intestinal tuberculosis(ITB) has remained a dilemma for most of the clinicians in the developing world, which are endemic for ITB, and where the disease burden of inflammatory bowel disease is on the rise. Although, there are certain clinical(diarrhea/hematochezia/perianal disease common in CD; fever/night sweats common in ITB), endoscopic(longitudinal/aphthous ulcers common in CD; transverse ulcers/patulous ileocaecal valve common in ITB), histologic(caseating/confluent/large granuloma common in ITB; microgranuloma common in CD), microbiologic(positive stain/culture for acid fast-bacillus in ITB), radiologic(long segment involvement/comb sign/skip lesions common in CD; necrotic lymph node/contiguous ileocaecal involvement common in ITB), and serologic differences between CD and ITB, the only exclusive features are caseation necrosis on biopsy, positive smear for acid-fast bacillus(AFB) and/or AFB culture, and necrotic lymph node on cross-sectional imaging in ITB. However,these exclusive features are limited by poor sensitivity, and this has led to the development of multiple multi-parametric predictive models. These models are also limited by complex formulae, small sample size and lack of validation across other populations. Several new parameters have come up including the latest Bayesian meta-analysis, enumeration of peripheral blood T-regulatory cells, and updated computed tomography based predictive score. However, therapeutic anti-tubercular therapy(ATT) trial, and subsequent clinical and endoscopic response to ATT is still required in a significant proportion of patients to establish the diagnosis. Therapeutic ATT trial is associated with a delay in the diagnosis of CD, and there is a need for better modalities for improved differentiation and reduction in the need for ATT trial.

复合手术治疗颈内动脉C1远段巨大动脉瘤1例

患者,女性,70岁。因＂反复头晕10余年,加重1周＂于2015年8月10日入院。查体：右侧乳突部位可见局部皮肤隆起,可触及搏动,边界不清,活动性差。既往有高血压病史,无冠心病、糖尿病病史。头颈CT血管造影（computed tomographic angiography,CTA）检查：右侧颈内动脉间发现一个4 cm×5 cm瘤样扩张,位于C1远段,近段迂曲成角约90°（见图1）。术前造影检查：颅内Wills环完整,

Computed tomography colonography in 2014:An update on technique and indications

Twenty years after its introduction, computed tomographic colonography (CTC) has reached its maturity, and it can reasonably be considered the best radiological diagnostic test for imaging colorectal cancer (CRC) and polyps. This examination technique is less invasive than colonoscopy (CS), easy to perform, and standardized. Reduced bowel preparation and colonic distention using carbon dioxide favor patient compliance. Widespread implementation of a new image reconstruction algorithm has minimized radiation exposure, and the use of dedicated software with enhanced views has enabled easier image interpretation. Integration in the routine workflow of a computer-aided detection algorithm reduces perceptual errors, particularly for small polyps. Consolidated evidence from the literature shows that the diagnostic performances for the detection of CRC and large polyps in symptomatic and asymptomatic individuals are similar to CS and are largely superior to barium enema, the latter of which should be strongly discouraged. Favorable data regarding CTC performance open the possibility for many different indications, some of which are already supported by evidence-based data: incomplete, failed, or unfeasible CS; symptomatic, elderly, and frail patients; and investigation of diverticular disease. Other indications are still being debated and, thus, are recommended only if CS is unfeasible: the use of CTC in CRC screening and in surveillance after surgery for CRC or polypectomy. In order for CTC to be used appropriately, contraindications such as acute abdominal conditions (diverticulitis or the acute phase of inflammatory bowel diseases) and surveillance in patients with a long-standing history of ulcerative colitis or Crohn&#x02019;s disease and in those with hereditary colonic syndromes should not be overlooked. This will maximize the benefits of the technique and minimize potential sources of frustration or disappointment for both referring clinicians and patients.

Tomographic PIV investigation of coherent structures in a turbulent boundary layer flow

Tomographic particle image velocimetry was used to quantitatively visualize the three-dimensional co- herent structures in the logarithmic region of the turbulent boundary layer in a water tunnel. The Reynolds number based on momentum thickness is Reo = 2 460. The in- stantaneous velocity fields give evidence of hairpin vortices aligned in the streamwise direction forming very long zones of low speed fluid, which is flanked on either side by high- speed ones. Statistical support for the existence of hairpins is given by conditional averaged eddy within an increasing spanwise width as the distance from the wall increases, and the main vortex characteristic in different wall-normal re- gions can be reflected by comparing the proportion of ejec- tion and its contribution to Reynolds stress with that of sweep event. The pre-multiplied power spectra and two-point cor- relations indicate the presence of large-scale motions in the boundary layer, which are consistent with what have been termed very large scale motions （VLSMs）. The three dimen-sional spatial correlations of three components of veloc- ity further indicate that the elongated low-speed and high- speed regions will be accompanied by a counter-rotating roll modes, as the statistical imprint of hairpin packet structures, all of which together make up the characteristic of coherent structures in the logarithmic region of the turbulent boundary layer （TBL）.

Relationship between Mesozoic Magmatism and Subduction in the Da Hinggan-Yanshan Area

High-resolution tomographic images of the belt crossing the Japan Trench-Changbai Mountains-Dong Ujimqin Qi are represented in this paper, revealing the shape of a subducted slab in the western Pacific region and characteristics of the lithospheric structures under the Changbai Mountains and the Da Hinggan Mountains. Studies of the spatial distribution, subduction time and the time-lag between the subduction and magmatism, combined with petrology and isotope geochemistry of the Late Mesozoic volcano-plutonic rocks from the Da Hinggan Mountains-Yanshan Mountains have further proved the independence of magmatic activities from the subduction of the Pacific plate. The Mesozoic tectono-thermal evolutionary history and structural characteristics of the lithosphere in the Da Hinggan Mountains and North China suggest that the formation and evolution of magma have probably a close relationship with the delamination and thinning of the continental lithosphere and the underplating resulting from the consequent upwelling of the asthenosphere. On the other hand, the large-scale strike-slip fault system, resulting from sinistral shearing of the Pacific plate relative to the Asian continent in the Mesozoic, is responsible for the formation and emplacement of magma on the continental margin. It was the intense crust-mantle interaction, together with structural deformation at the shallower levels that led to the large tectono-magmatic belt in the East Asian continental margin.

A review on reflection-waveform inversion

Full-waveform inversion(FWI)utilizes optimization methods to recover an optimal Earth model to best fit the observed seismic record in a sense of a predefined norm.Since FWI combines mathematic inversion and full-wave equations,it has been recognized as one of the key methods for seismic data imaging and Earth model building in the fields of global/regional and exploration seismology.Unfortunately,conventional FWI fixes background velocity mainly relying on refraction and turning waves that are commonly rich in large offsets.By contrast,reflections in the short offsets mainly contribute to the reconstruction of the high-resolution interfaces.Restricted by acquisition geometries,refractions and turning waves in the record usually have limited penetration depth,which may not reach oil/gas reservoirs.Thus,reflections in the record are the only source that carries the information of these reservoirs.Consequently,it is meaningful to develop reflection-waveform inversion(RWI)that utilizes reflections to recover background velocity including the deep part of the model.This review paper includes:analyzing the weaknesses of FWI when inverting reflections;overviewing the principles of RWI,including separation of the tomography and migration components,the objective functions,constraints;summarizing the current status of the technique of RWI;outlooking the future of RWI.

Splanchnic vein thrombosis in necrotizing acute pancreatitis: Detection by computed tomographic venography

AIM: To assess the diagnostic accuracy of computed tomographic venography(CTV) for splanchnic vein thrombosis(SVT) detection in necrotizing acute pancreatitis(AP) patients.METHODS:Forty-three patients with necrotizing AP who underwent both CTV and digital subtraction angiography(DSA)within 3 d were analyzed in this retrospective comparative study.All CTV procedures were performed with a dual-source CT scanner.The presence and location of SVT were determined via blinded imaging data analyses.RESULTS:According to the DSA results,17(39.5%)of the total 43 patients had SVT.The sensitivity,specificity,positive and negative predictive values of CTV for SVT detection were 100%(95%CI:77.1%-100%),92.3%(95%CI:73.4%-98.7%),89.5%(95%CI:65.5%-98.2%)and 100%(95%CI:82.8%-100%),respectively.CONCLUSION:CTV is an effective examination for SVT detection in patients with necrotizing AP with high positive and negative predictive values.

New era of colorectal cancer screening

Colorectal cancer(CRC) is the 2^(nd) most common cancer in women and 3^(rd) most common cancer in men worldwide. Most CRCs develop from adenomatous polyps arising from glandular epithelium. Tumor growth is initiated by mutation of the tumor suppressor gene APC and involves other genetic mutations in a stepwise process over years. Both hereditary and environmental factors contribute to the development of CRC. Screening has been proven to reduce the incidence of CRC. Screening has also contributed to the decrease in CRC mortality in the United States. However,CRC incidence and/or mortality remain on the rise in some parts of the world(Eastern Europe,Asia,and South America),likely due to factors including westernized diet,lifestyle,and lack of healthcare infrastructure. Multiple screening options are available,ranging from direct radiologic or endoscopic visualization tests that primarily detect premalignant or malignant lesions such as flexible sigmoidoscopy,optical colonoscopy,colon capsule endoscopy,computed tomographic colonography,and double contrast barium enema- to stool based tests which primarily detect cancers,including fecal DNA,fecal immunochemical test,and fecal occult blood test. The availability of some of these tests is limited to areas with high economic resources. This article will discuss CRC epidemiology,pathogenesis,risk factors,and screening modalities with a particular focus on new technologies.

Quantitative Investigation of Tomographic Effects in Abnormal Regions of Complex Structures

The detection of abnormal regions in complex structures is one of the most challenging targets for underground space engineering.Natural or artificial geologic variations reduce the effectiveness of conventional exploration methods.With the emergence of real-time monitoring,seismic wave velocity tomography allows the detection and imaging of abnormal regions to be accurate,intuitive,and quantitative.Since tomographic results are affected by multiple factors in practical small-scale applications,it is necessary to quantitatively investigate those influences.We adopted an improved three-dimensional(3D)tomography method combining passive acoustic emission acquisition and active ultrasonic measurements.By varying individual parameters(i.e.,prior model,sensor configuration,ray coverage,event distributions,and event location errors),37 comparative tests were conducted.The quantitative impact of different factors was obtained.Synthetic experiments showed that the method could effectively adapt to complex structures.The optimal input parameters based on quantization results can significantly improve the detection reliability in abnormal regions.

Structures of the Bohai Petroliferous Area,Bohai Bay Basin

This paper, for the first time, deals with a more systematic study of the structures in the Bohai petroliferous area that covers nearly one third of the Bohai Bay basin. The study mainly involves the effects of preexisting basement faults on the basin formation, the characteristics of basin geometry and kinetics, the modelling of the tectonic-thermal history, the polycyclicity and heterogeneity in the structural evolution and the natural seismic tomographic images of the crust and upper mantle. The authors analyze the features of the dynamic evolution of the basin in the paper and point out that the basin in the Bohai petroliferous area is an extensional pull-apart basin.