Narrow-band tomographic radar imaging of precession cone targets

The principle and method of the narrow-band tomo-graphic radar imaging （NBTRI） of the precession cone target are studied. Firstly, the motion model and electromagnetic scattering characteristics of the precession cone target are introduced. Secondly, based on the traditional NBTRI algorithm, a novel narrow-band tomography clean radar imaging （NBTCRI） algorithm is proposed to enhance the image quality of NBTRI results. In addition, the resolution performance of the NBTRI algorithm is analyzed. Finally, based on the ideal scattering point model, this paper discusses the relationship between the precession angle and the estimated target size from NBTRI results. By using the target＇s chamber data, NBTRI and NBTCRI results of the precession cone target are further analyzed, which indicates the effectiveness of the proposed method.

Evaluation of recurrence in gastric carcinoma: Comparison of contrast-enhanced computed tomography and positron emission tomography/computed tomography

AIM To compare the value of contrast-enhanced abdominal computed tomography(CT) and fluorodeoxyglucose(FDG) positron emission tomography/computed tomography(PET/CT) for detecting gastric carcinoma recurrence.METHODS We retrospectively examined data from 2475 patients who underwent both contrast-enhanced abdominal CT and FDG PET/CT for the surveillance of gastric carcinoma curative resection. Patients had an interval of less than 1 mo between their CT and PET/CT scans. Sixty patients who had recurrence were enrolled. Among 1896 patients who did not have recurrence, 60 were selected by simple random sampling. All CT and PET/CT images were reviewed retrospectively by two reviewers blinded to all clinical and pathologic information except curative resection due to gastric carcinoma. RESULTS The pathological stage of the recurrence group was statistically significantly higher than that of the control group(P < 0.001). In the 60 patients who had recurrence, there were 79 recurrent lesions. Fortyfour patients had only one location of recurrence, 13 patients had two locations, and 3 patients had three. In the detection of patient-based overall recurrence, no statistically significant differences existed between the two modalities(P = 0.096). However, for peritoneal carcinomatosis, CT had a statistically significantly higher sensitivity compared to PET/CT(96% vs 50%, P = 0.001). Adenocarcinoma was the most common type of gastric carcinoma. On the pathology-based analysis, CT also had a statistically significantly higher sensitivity compared to PET/CT(98% vs 80%, P = 0.035).CONCLUSION Contrast-enhanced CT was superior to PET/CT in the detection of peritoneal carcinomatosis and pathologic type of adenocarcinoma.

Development of tomographic reconstruction for three-dimensional optical imaging:From the inversion of light propagation to artificial intelligence

Optical molecular tomography(OMT)is an imaging modality which uses an optical signal,especially near-infrared light,to reconstruct the three-dimensional information of the light source in biological tissue.With the advantages of being low-cost,noninvasive and having high sensitivity,OMT has been applied in preclinical and clinical research.However,due to its serious ill-posedness and illcondition,the solution of OMT requires heavy data analysis and the reconstruction quality is limited.Recently,the artificial intelligence(commonly known as AI)-based methods have been proposed to provide a different tool to solve the OMT problem.In this paper,we review the progress on OMT algorithms,from conventional methods to AI-based methods,and we also give a prospective towards future developments in this domain.

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）.

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’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.

Study on local topology model of low/high streak structures in wall-bounded turbulence by tomographic time-resolved particle image velocimetry

The relationship between the in the logarithmic law （log-law） region of bursting event and the low/high-speed streak a turbulent boundary layer is investigated. A tomographic time-resolved particle image velocimetry （TRPIV） system is used to measure the instantaneous three-dimensional-three-component （3D-3C） velocity field. The momentum thickness based Reynolds number is about 2 460. The topological information in the log-law region is obtained experimentally. It is found that the existence of the quadrupole topological structure implies a three-pair hairpin-like vortex packet, which is in connection with the low/high-speed streak. An idealized 3D topological model is then proposed to characterize the observed hairpin vortex packet and low/high-speed streak.

Convection and correlation of coherent structure in turbulent boundary layer using tomographic particle image velocimetry

The present experimental work focuses on a new model for space-time correlation and the scale-dependencies of convection velocity and sweep velocity in turbulent boundary layer over a flat wail. A turbulent boundary layer flow at Reo = 2460 is measured by tomographic particle image velocimetry （tomographic PIV）. It is demonstrated that arch, cane, and hairpin vortices are dominant in the logarithmic layer. Hairpins and hairpin packets are responsible for the elongated low-momentum zones observed in the instantaneous flow field. The conditionally-averaged coherent structures systemically illustrate the key roles of hairpin vortice in the turbulence dynamic events, such as ejection and sweep events and energy transport. The space-time correlations of instantaneous streamwise fluctuation velocity are calculated and confirm the new elliptic model for the space-time correlation instead of Taylor hypothesis. The convection velocities derived from the space-time correlation and conditionally-averaged method both suggest the scaling with the local mean velocity in the logarithmic layer. Convection velocity result based on Fourier decomposition （FD） shows stronger scale- dependency in the spanwise direction than in streamwise direction. Compared with FD, the proper orthogonal decomposition （POD） has a distinct distribution of convection velocity for the large- and small-scales which are separated in light of their contributions of turbulent kinetic energy.

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.

Computed tomographic colonography:Hope or hype?

Computed tomographic colonography (CTC) is a promising emerging technology for imaging of the colon. This concise review discusses the currently available data on CTC technique,test characteristics,acceptance,safety,cost-effectiveness,follow-up strategy,and extracolonic findings. In summary,CTC technique is still evolving,and further research is needed to clarify the role of automated colonic insufflation,smooth-muscle relaxants,intravenous and oral contrast,soft-ware rendering,and patient positioning. Currently,full bowel preparation is still required to achieve optimal results. The sensitivity for detecting large polyps (> 1 cm) can be as high as 85%,with specificity of up to 97%. These test characteristics are almost comparable to those of conventional colonoscopy. Patient acceptance of CTC is generally higher than that for colonoscopy,especially in patients who have never undergone either procedure. CTC is generally safe,although uncommon instances of colonic perforation have been documented. In terms of cost-effectiveness,most decision analyses have concluded that CTC would only be cost-effective if it were considerably cheaper than conventional colonoscopy. The proper follow-up strategy for small polyps or incidental extracolonic findings discovered during CTC is still under debate. At present,the exact clinical role of virtual colonoscopy still awaits determination. Even though widespread CTC screening is not available today,in the future there may eventually be a role for this technology. Technological advances in this area will undoubtedly continue,with multi-detector row CT scanners allowing thinner collimation and higher reso-lution images. Stool-tagging techniques are likely to evolve and may eventually allow for low-preparation CTC. Perceptual and fatigue-related reading errors can potentially be minimized with the help of computer-aided detection software. Further research will define the exact role of this promising technology in our diagnostic armamentarium.

THE HIGH RESOLUTION SEISMIC TOMOGRAPHIC IMAGE IN QINGHAI—TIBET PLATEAU AND ITS DYNAMIC IMPLICATIONS

The Qinghai—Tibet plateau and its surrounding areas including Indian subcontinent, Xinjiang, Mongolia, is a largest lithosphere convergence place in the world, which characterized by continent\|continent collision with a thick crust and lithosphere. The high resolution seismic surface wave tomographic inversion has been conducted for studying the 3D velocity structure of crust and upper mantle in those areas. The seismic surface waveform data are from the archives of the CDSN, GSN and GEOSCOPE. About 2400 long period surface waveform recordings are available for both dispersion and waveform tomographic inversion. The block inversion by grid 1°×1°in Qinghai—Tibet plateau and 2°×2°in the surrounding areas were adapted. The resulting maps show the high resolution 3D shear wave velocity variation from earth’s surface to 400km depth.

Internal Structure of Cambrian Fossil Embryo Markuelia Revealed in the Light of Synchrotron Radiation X-ray Tomographic Microscopy

In the light of Synchrotron Radiation X-ray Tomographic Microscopy （SRXTM）, the internal structure of Markuelia hunanensis is revealed. In one example, vitrification and peeling show the annuli hidden under the chorion. Sectioning and 3-D reconstruction display an intact digestive tract from the inverted introvert to the terminal anus. The inverted introvert forms a rugby cavum. The following digestive tract is rope-like coiling, parallel to the body axis, about 650 μm in length, and uniform in diameter （-80 μm）. An exquisitely preserved pipe-like structure is hidden in the middle of the rope-like structure, diameter 20--40 lam, with a length of -120 μm. We interpret this pipe-like structure as the possible epidermis of the gut and its surroundings as the possible residue of musculature, similar to that in Priapulans. The two symmetrical rod-shape structures connecting the body wall and digestive tract are interpreted as the possible retractor muscles. After comparing the well preserved Left-form and Right-form Body of Markuelia, we suggest that they may represent a dimorphism. Counted directly, one sample of Markuelia hunanensis possesses 62 annulations and the other 68.

Magnetic resonance imaging and multi-detector computed tomography assessment of extracellular compartment in ischemic and non-ischemic myocardial pathologies

Myocardial pathologies are major causes of morbidity and mortality worldwide. Early detection of loss of cellular integrity and expansion in extracellular volume(ECV) in myocardium is critical to initiate effective treatment. The three compartments in healthy myocardium are: intravascular(approximately 10% of tissue volume), interstitium(approximately 15%) and intracellular(approximately 75%). Myocardial cells, fibroblasts and vascular endothelial/smooth muscle cells represent intracellular compartment and the main proteins in the interstitium are types Ⅰ/Ⅲ collagens. Microscopic studies have shown that expansion of ECV is an important feature of diffuse physiologic fibrosis(e.g., aging and obesity) and pathologic fibrosis [heart failure, aortic valve disease, hypertrophic cardiomyopathy, myocarditis, dilated cardiomyopathy, amyloidosis, congenital heart disease, aortic stenosis, restrictive cardiomyopathy(hypereosinophilic and idiopathic types), arrythmogenic right ventricular dysplasia and hypertension]. This review addresses recent advances in measuring of ECV in ischemic and non-ischemic myocardial pathologies. Magnetic resonance imaging(MRI) has the ability to characterize tissue proton relaxation times(T1, T2, and T2*). Proton relaxation times reflect the physical and chemical environments of water protons in myocardium. Delayed contrast enhanced-MRI(DE-MRI) and multi-detector computed tomography(DE-MDCT) demonstrated hyper-enhanced infarct, hypo-enhanced microvascular obstruction zone and moderately enhanced peri-infarct zone, but are limited for visualizing diffuse fibrosis and patchy microinfarct despite the increase in ECV. ECV can be measured on equilibrium contrast enhanced MRI/MDCT and MRI longitudinal relaxation time mapping. Equilibrium contrast enhanced MRI/MDCT and MRI T1 mapping is currently used, but at a lower scale, as an alternative to invasive sub-endomyocardial biopsies to eliminate the need for anesthesia, coronary catheterization and possibility of tissue sampling error. Similar to delayed contrast enhancement, equilibrium contrast enhanced MRI/MDCT and T1 mapping is completely noninvasive and may play a specialized role in diagnosis of subclinical and other myocardial pathologies. DE-MRI and when T1-mapping demonstrated sub-epicardium, sub-endocardial and patchy mid-myocardial enhancement in myocarditis, Behcet's disease and sarcoidosis, respectively. Furthermore, recent studies showed that the combined technique of cine, T2-weighted and DE-MRI technique has high diagnostic accuracy for detecting myocarditis. When the tomographic techniques are coupled with myocardial perfusion and left ventricular function they can provide valuable information on the progression of myocardial pathologies and effectiveness of new therapies.

Static CSI Extraction and Application in the Tomographic Channel Model

In this paper, the statistical properties of parameters of each path in wireless channel models are analyzed to prove that there is the static part in channel state information(CSI) which can be extracted from huge amounts of CSI data. Based on the analysis, the concept of the Tomographic Channel Model(TCM) is presented. With cluster algorithms, the static CSI database can be built in an off-line manner. The static CSI database can provide prior information to help pilot design to reduce overhead and improve accuracy in channel estimation. A new CSI prediction method and a new channel estimation method between different frequency bands are introduced based on the static CSI database. Using measurement data, the performance of the new channel prediction method is compared with that of the Auto Regression(AR) predictor. The results indicate that the prediction range of the new method is better than that of the AR method and the new method can predict with fewer pilot symbols. Using measurement data, the new channel estimation method between different frequency bands can estimate the CSI of one frequency band based on known CSI of another frequency band without any feedback.

Granulocyte colony-stimulating factor-producing squamous cell carcinoma of the tongue exhibiting characteristic fluorine-18 deoxyglucose accumulation on positron emission tomography–computed tomography: A case report

BACKGROUND Granulocyte colony-stimulating factor(G-CSF)is a cytokine produced in inflammatory environments that induces differentiation and proliferation of neutrophils in bone marrow.We report a rare case of aggressive G-CSFproducing squamous cell carcinoma of the tongue exhibiting fluorine-18 deoxyglucose(FDG)accumulation in primary lesion,metastatic lymph nodes,spleen,and bone marrow on positron emission tomography–computed tomography(PET/CT).CASE SUMMARY We report a 58-year-old female with a rapid enlarged lingual mass with partial necrosis.Blood test results from the initial examination revealed a leukocyte count of 21380/μL.On PET/CT,extensive FDG accumulation was observed in the tongue and bilateral cervical lymph nodes,with elevated FDG accumulation in the spleen and bone marrow although no distant metastases were observed.We performed partial glossectomy and bilateral neck dissection.Immunohistochemical staining with G-CSF antibodies on biopsy specimen and resected samples revealed that both specimens were G-CSF positive.This is a rare case of G-CSF producing tongue carcinoma with elevated FDG accumulation in the spleen and bone marrow.CONCLUSION In patients with the tongue cancer and hyperleukocytosis,where FDG accumulations in the spleen and bone marrow are observed using PET/CT and when these accumulations are not caused by metastasis,G-CSF-producing tumors,with associated poor prognosis,should be considered.

Tomographic PIV investigation on coherent vortex structures over shark-skin-inspired drag-reducing riblets

Nature has shown us that the microstructure of the skin of fast-swimming sharks in the ocean can reduce the skin friction drag due to the well-known shark-skin effect.In the present study,the effect of shark-skin-inspired riblets on coherent vortex structures in a turbulent boundary layer（TBL） is investigated.This is done by means of tomographic particle image velocimetry（TPIV） measurements in channel fl ws over an acrylic plate of drag-reducing riblets at a friction Reynolds number of 190.The turbulent fl ws over drag-reducing riblets are verifie by a planar time-resolved particle image velocimetry（TRPIV） system initially,and then the TPIV measurements are performed.Two-dimensional（2D） experimental results with a dragreduction rate of around 4.81% are clearly visible over triangle riblets with a peak-to-peak spacing s＋of 14,indicating from the drag-reducing performance that the buffer layer within the TBL has thickened;the logarithmic law region has shifted upward and the Reynolds shear stress decreased.A comparison of the spatial topological distributions of the spanwise vorticity of coherent vortex structures extracted at different wall-normal heights through the improved quadrant splitting method shows that riblets weaken the amplitudesof the spanwise vorticity when ejection（Q2） and sweep（Q4） events occur at the near wall,having the greatest effect on Q4 events in particular.The so-called quadrupole statistical model for coherent structures in the whole TBL is verified Meanwhile,their spatial conditional-averaged topological shapes and the spatial scales of quadrupole coherent vortex structures as a whole in the overlying turbulent fl w over riblets are changed,suggesting that the riblets dampen the momentum and energy exchange between the regions of near-wall and outer portion of the TBL by depressing the bursting events（Q2 and Q4）,thereby reducing the skin friction drag.

Myocardial bridging analysis by coronary computed tomographic angiography in a Saudi population

AIM: To assess the incidence, location, morphology and clinical association of myocardial bridging in a Saudi population using coronary computed tomographic angiography(CCTA). METHODS: A total of 350 CCTA of Saudi patients were included in this study(236 men, 114 women) with a mean age of 56.3 years. All patients were examined for appropriateness criteria of CCTA indications(typical chest pain, recent onset cardiomyopathy, left bundle branch block, etc.). The scans were retrospectively reviewed for the presence of myocardial bridging and any other pathological association. RESULTS: Myocardial bridging was found in 89 of 350(22.5%) patients. Most of the intramuscular segments were of the superficial type and found in the mid left anterior descending(LAD)(24.6%), followed by distal LAD(3.7%), diagonal branches(2%), ramus intermedius artery(1.4%) and obtuse marginal artery(0.8%). No myocardial bridging was detected in the right coronary or circumflex arteries. No significant differences were found between males and females(P = 0.14). Coronary artery atherosclerosis was found in 51 of 89(57.3%) patients with MB. Atherosclerotic plaques were not detected in the intramuscular or distal segment of bridging arteries. Dynamic compression was observed in 35(94.5%) patients with full encasement. No evidence of myocardial hypoperfusion was found in the territories supplied by the bridging arteries. CONCLUSION: CCTA is excellent in analyzing myocardial bridging in a Saudi population and the results are comparable to other populations. However, finding the real incidence may need a large multicenter study.

Assessment of sub-milli-sievert abdominal computed tomography with iterative reconstruction techniques of different vendors

AIM: To assess diagnostic image quality of reduced dose(RD) abdominal computed tomography(CT) with 9 iterative reconstruction techniques(IRTs) from 4 different vendors to the standard of care(SD) CT.METHODS: In an Institutional Review Board approved study, 66 patients(mean age 60 ± 13 years, 44 men, and 22 women) undergoing routine abdomen CT on multi-detector CT(MDCT) scanners from vendors A, B, and C(≥ 64 row CT scanners)(22 patients each) gave written informed consent for acquisition of an additional RD CT series. Sinogram data of RD CT was reconstructed with two vendor-specific and a vendor-neutral IRTs(A-1, A-2, A-3; B-1, B-2, B-3; and C-1, C-2, C-3) and SD CT series with filtered back projection. Subjective image evaluation was performed by two radiologists for each SD and RD CT series blinded and independently. All RD CT series(198) were assessed first followed by SD CT series(66). Objective image noise was measured for SD and RD CT series. Data were analyzed by Wilcoxon signed rank, kappa, and analysis of variance tests.RESULTS: There were 13/50, 18/57 and 9/40 missed lesions(size 2-7 mm) on RD CT for vendor A, B, and C, respectively. Missed lesions includes liver cysts, kidney cysts and stone, gall stone, fatty liver, and pancreatitis. There were also 5, 4, and 4 pseudo lesions(size 2-3 mm) on RD CT for vendor A, B, and C, respectively. Lesions conspicuity was sufficient for clinical diagnostic performance for 6/24(RD-A-1), 10/24(RD-A-2), and 7/24(RD-A-3) lesions for vendor A; 5/26(RD-B-1), 6/26(RD-B-2), and 7/26(RD-B-3) lesions for vendor B; and 4/20(RD-C-1) 6/20(RD-C-2), and 10/20(RD-C-3) lesions for vendor C(P = 0.9). Mean objective image noise in liver was significantly lower for RD A-1 compared to both RD A-2 and RD A-3 images(P < 0.001). Similarly, mean objective image noise lower for RD B-2(compared to RD B-1, RD B-3) and RD C-3(compared to RD C-1 and C-2)(P = 0.016).CONCLUSION: Regardless of IRTs and MDCT vendors, abdominal CT acquired at mean CT dose index volume 1.3 m Gy is not sufficient to retain clinical diagnostic performance.

Advances in the application of optical coherence tomography in the assessment of ischemic stroke

Ischemic stroke has high morbidity,mortality,disability rate and recurrence.It is the one of the main diseases that threaten people's health in China.Its etiology,pathogenesis,and reaction mechanism has been the research hotspot and difficulty of related studies have shown that the optical coherence tomography technology is an effective measure to evaluate ischemic cerebral apoplexy.Optical coherence tomography(OCT)is a gradually developed and mature imaging technology in recent years,and there are related studies on internal carotid artery,retina and coronary artery.Based on the above background,this paper reviews the research progress of optical coherence tomography in the assessment of the etiology,pathogenesis and response mechanism of ischemic stroke.

Study of crustal seismic velocity in the Weihe fault depression basin by seismic tomographic imaging

This paper gives a study of 3 D crustal seismic velocity changes in the Weihe fault depression basin, in which the overlapping sphere iterative reconstruction method of tomographic image was used in connection with the two point fast ray tracing technique. By means of theoretical modeling, the monitoring function of the observatory network system of Shaanxi Province was tested. Using the seismic data of the network, seismic tomographic inversion imaging of the crustal seismic velocity in the Weihe fault basin was studied. The results are as follows: In the Tongchuan Yaoxian area to the north of Jingyang, there is a high velocity region extending nearly in NS direction, the highest velocity value is around Tongchuan. To the southwest of Shangxian and Lantian, there is a low velocity zone about 100 km long and about 50 km wide, inside which there are two regions of the lowest velocity 50 km apart. The epicenters of historical strong earthquakes are mainly on the boundary of high velocity regions or in regions of fairly high velocity. In the eastern and western parts of the south margin of the Qinling Mountains, there is an obvious lateral nonhomogeneity of seismic velocity.

Findings on intraprocedural non-contrast computed tomographic imaging following hepatic artery embolization are associated with development of contrast-induced nephropathy

BACKGROUND Contrast-induced nephropathy(CIN)is a reversible form of acute kidney injury that occurs within 48-72 h of exposure to intravascular contrast material.CIN is the third leading cause of hospital-acquired acute kidney injury and accounts for 12%of such cases.Risk factors for CIN development can be divided into patientand procedure-related.The former includes pre-existing chronic renal insufficiency and diabetes mellitus.The latter includes high contrast volume and repeated exposure over 72 h.The incidence of CIN is relatively low(up to 5%)in patients with intact renal function.However,in patients with known chronic renal insufficiency,the incidence can reach up to 27%.AIM To examine the association between renal enhancement pattern on non-contrast enhanced computed tomographic(CT)images obtained immediately following hepatic artery embolization with development of CIN.METHODS Retrospective review of all patients who underwent hepatic artery embolization between 01/2010 and 01/2011(n=162)was performed.Patients without intraprocedural CT imaging(n=51),combined embolization/ablation(n=6)and those with chronic kidney disease(n=21)were excluded.The study group comprised of 84 patients with 106 procedures.CIN was defined as 25%increase above baseline serum creatinine or absolute increase≥0.5 mg/dL within 72 h post-embolization.Post-embolization CT was reviewed for renal enhancement patterns and presence of renal artery calcifications.The association between noncontrast CT findings and CIN development was examined by Fisher’s Exact Test.RESULTS CIN occurred in 11/106(10.3%)procedures(Group A,n=10).The renal enhancement pattern in patients who did not experience CIN(Group B,n=74 with 95/106 procedures)was late excretory in 93/95(98%)and early excretory(EE)in 2/95(2%).However,in Group A,there was a significantly higher rate of EE pattern(6/11,55%)compared to late excretory pattern(5/11)(P<0.001).A significantly higher percentage of patients that developed CIN had renal artery calcifications(6/11 vs 20/95,55%vs 21%,P=0.02).CONCLUSION A hyperdense renal parenchyma relative to surrounding skeletal muscle(EE pattern)and presence of renal artery calcifications on immediate post-HAE noncontrast CT images in patients with low risk for CIN are independently associated with CIN development.