Characterization of tumors of jaw:Additive value of contrast enhancement and dual-energy computed tomography

BACKGROUND Currently,the differentiation of jaw tumors is mainly based on the lesion’s morphology rather than the enhancement characteristics,which are important in the differentiation of neoplasms across the body.There is a paucity of literature on the enhancement characteristics of jaw tumors.This is mainly because,even though computed tomography(CT)is used to evaluate these lesions,they are often imaged without intravenous contrast.This study hypothesised that the enhancement characteristics of the solid component of jaw tumors can aid in the differentiation of these lesions in addition to their morphology by dual-energy CT,therefore improving the ability to differentiate between various pathologies.AIM To evaluate the role of contrast enhancement and dual-energy quantitative parameters in CT in the differentiation of jaw tumors.METHODS Fifty-seven patients with jaw tumors underwent contrast-enhanced dual-energy CT.Morphological analysis of the tumor,including the enhancing solid component,was done,followed by quantitative analysis of iodine concentration(IC),water concentration(WC),HU,and normalized IC.The study population was divided into four subgroups based on histopathological analysis-central giant cell granuloma(CGCG),ameloblastoma,odontogenic keratocyst(OKC),and other jaw tumors.A one-way ANOVA test for parametric variables and the Kruskal-Wallis test for nonparametric variables were used.If significant differences were found,a series of independent t-tests or Mann-Whitney U tests were used.RESULTS Ameloblastoma was the most common pathology(n=20),followed by CGCG(n=11)and OKC.CGCG showed a higher mean concentration of all quantitative parameters than ameloblastomas(P<0.05).An IC threshold of 31.35×100μg/cm^(3) had the maximum sensitivity(81.8%)and specificity(65%).Between ameloblastomas and OKC,the former showed a higher mean concentration of all quantitative parameters(P<0.001),however when comparing unilocular ameloblastomas with OKCs,the latter showed significantly higher WC.Also,ameloblastoma had a higher IC and lower WC compared to“other jaw tumors”group.CONCLUSION Enhancement characteristics of solid components combined with dual-energy parameters offer a more precise way to differentiate between jaw tumors.

Prevalence and risk factors of osteoporosis detected by dual-energy X-ray absorptiometry among Chinese patients with primary biliary cholangitis

BACKGROUND Osteoporosis is an extrahepatic complication of primary biliary cholangitis(PBC)that increases the risk of fractures and mortality.However,Epidemiological studies of osteoporosis in patients with PBC in China and the Asia-Pacific region is lack.AIM To assess the prevalence and clinical characteristics of osteoporosis in Chinese patients with PBC.METHODS This retrospective analysis included consecutive patients with PBC from a tertiary care center in China who underwent bone mineral density(BMD)assessment using dual-energy X-ray absorptiometry between January 2013 and December 2021.We defined subjects with T-scores≤-2.5 in any sites(L1 to L4,femoral neck,or total hip)as having osteoporosis.Demographic,serological,clinical,and histological data were collected.Independent risk factors for osteoporosis were identified by multivariate logistic regression analysis.RESULTS A total of 268 patients with PBC[236 women(88.1%);mean age,56.7±10.6 years;163 liver biopsies(60.8%)]were included.The overall prevalence of osteoporosis in patients with PBC was 45.5%(122/268),with the prevalence of osteoporosis in women and men being 47.0%and 34.4%,respectively.The prevalence of osteoporosis in postmenopausal women was significantly higher than that in premenopausal women(56.3%vs 21.0%,P<0.001).Osteoporosis in patients with PBC is associated with age,fatigue,menopausal status,previous steroid therapy,body mass index(BMI),splenomegaly,gastroesophageal varices,ascites,Mayo risk score,histological stage,alanine aminotransferase,albumin,bilirubin,platelet and prothrombin activity.Multivariate regression analysis identified that older age,lower BMI,previous steroid therapy,higher Mayo risk score,and advanced histological stage as the main independent risk factors for osteoporosis in PBC.CONCLUSION Osteoporosis is very common in Chinese patients with PBC,allowing for prior screening of BMD in those PBC patients with older age,lower BMI,previous steroid therapy and advanced liver disease.

Association between body mass index and body fat measured by dual-energy X-ray absorptiometry (DXA) in China: a systematic review and meta-analysis

Objective:We examined the association between body mass index(BMI)and body fat percentage(BF%)measured by dual-energy X-ray absorptiometry(DXA)among adults and children in China.Methods:We searched four databases-PubMed,China National Knowledge Infrastructure,Wanfang,and Vip for studies published in the past 22 years.Meta-analysis was conducted using random-or fixed-effect models.Results:In total of 21 studies met inclusion criteria and were included in review,and 17 ot them in meta-analysis.They were conducted across China.Their sample size ranged from 62 to 5726,and participants'age ranged from 6-80 years.Meta-analysis revealed strong associations between BMI and BF% measured by DXA in adults(pooled r=0.71,95% CI:0.66 to 0.74)and children(pooled r=0.60,95% CI:0.52 to 0.68).The association was stronger in Northern China than in East China in children(β=-0.40,95%CI:-0.65 to-0.14)and in Central China in adults(β=-0.25;95% CI:-0.51 to-0.01).Urban children's BMI was strongly associated with BF%than rural(β=0.19;95%CI:0.04 to 0.35),whereas it was stronger in adults living in rural than in urban(β=-0.35;95% CI:-0.66 to-0.05).Conclusions:BMI was strongly associated with BF%measured by DXA,and the association in children and adults in China varied by residence and region.

Prospective observational study on the prognosis of ureteral lesions caused by impacted stones via dual-energy spectral computed tomography

Objective Ureteral lesions caused by impacted ureteral stones are likely to result in postoperative ureteral stricture.On this basis,the study aimed to investigate if dual-energy spectral computed tomography can predict ureteral hardening caused by impacted stones and to explore the relationship between different types of ureteral lesions and the risk of ureteral stricture.Methods This prospective study collected data of 93 patients with impacted stones from hospital automation system during January 2018 to October 2019.They underwent an abdominal scan on a dual-energy spectral computed tomography.During surgery,the operator used ureteroscopy to identify ureteral lesions,which were classified into four categories:edema,polyps,pallor,and hardening.Seven months later,90 patients were reviewed for the degree of hydronephrosis.Results Endoscopic observations revealed 38(41%)cases of ureteral edema,20(22%)cases of polyps,13(14%)cases of pallor,and 22(24%)cases of hardening.There were significant differences in hydronephrosis,the period of impaction,the calcium concentration of the ureter,and the slope of the spectral Hounsfield unit curve between the four groups.After that,we evaluated the factors associated with ureteral hardening and found that the calcium concentration of the ureter and hydronephrosis remained independent predictors of ureteral hardening.Receiver operating characteristic curve analysis showed that 5.3 mg/cm^(3)calcium concentration of the ureter is an optimal cut-off value to predict ureteral hardening.The result of follow-up showed that 80 patients had complete remission of hydronephrosis,with a complete remission rate of 61.9%(13/21)in the hardening group and 97.1%(67/69)in the non-hardening group(p<0.001).Conclusion Calcium concentration of the ureter is an independent predictor of ureteral hardening.Patients with ureteral hardening have more severe hydronephrosis after ureteroscopic lithotripsy.When the calcium concentration of the ureter is less than 5.3 mg/cm^(3),ureteral lesions should be actively treated.

The application study of dual-energy CT nonlinearblending technique in pulmonary angiography

Objective This study aimed to explore the feasibility of enhancing image quality in computed tomography(CT) pulmonary angiography (CTPA) and reducing radiation dose using the nonlinear blending (NLB)technique of dual-energy CT.Methods A total of 61 patients scheduled for CTPA were enrolled, and 30 patients underwent dual-energyscanning. Nonlinear blending images (NLB group) and three groups of linear blending images (LB group,80 kV group, and 140 kV group) were reconstructed after scanning;31 patients underwent single-energyscanning (120 kV group). The CT values and standard deviations of the pulmonary trunk, left and rightpulmonary arteries, and ipsilateral back muscle at the bifurcation level of the left and right pulmonaryarteries were measured. The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of the fivegroups were calculated. The subjective image quality of the five groups was assessed. The radiation dosesof the dual- and single-energy groups were recorded and calculated.Results The CNR and SNR values of blood vessels in the NLB group were significantly higher than thosein the LB, 140 kV, and 80 kV groups (CNR of pulmonary artery trunk: t = 3.50, 4.06, 7.17, all P < 0.05;SNRof pulmonary trunk: t = 3.76, 4.71, 6.92, all P < 0.05). There were no statistical differences in the CNR andSNR values between the NLB group and 120 kV group (P > 0.05). The effective radiation dose of the dualenergygroup was lower than that of the single-energy group (t = –4.52, P < 0.05). The subjective scores ofimages in the NLB group were the highest (4.28 ± 0.74).Conclusion The NLB technique of dual-energy CT can improve the image quality of CTPA and reducethe radiation dose, providing more reliable imaging data for the clinical diagnosis of pulmonary embolism.

C型臂与G型臂激光定位透视对无神经症状腰椎骨折经皮椎弓根螺钉置入的有效性和安全性比较

目的 探讨C型臂与G型臂激光定位透视对无神经症状的腰椎骨折经皮椎弓根螺钉置入的有效性和安全性。方法 选取2020年9月—2022年10月邢台市人民医院收治的96例无神经症状的腰椎骨折患者,以随机数字表法分为研究组和对照组,每组48例。研究组给予G型臂激光定位透视下经皮椎弓根螺钉置入,对照组给予C型臂激光定位透视下经皮椎弓根螺钉置入。术后随访6个月,对比两组手术及透视情况、疼痛、腰椎功能、腰椎解剖学参数情况,统计两组并发症发生情况。结果 研究组术中出血量少于对照组,手术时间、辐射曝光时间、透视操作时间短于对照组,辐射曝光次数少于对照组(P <0.05)。研究组透视精准率高于对照组(P <0.05)。研究组螺钉植入准确度等级高于对照组(P <0.05)。两组术前、术后1 d、术后3 d、术后1个月VAS评分比较,经重复测量设计的方差分析,结果:(1)不同时间点VAS评分比较,差异有统计学意义(P <0.05);(2)两组VAS评分比较,差异无统计学意义(P>0.05);(3)两组VAS评分变化趋势比较,差异无统计学意义(P>0.05)。两组术前、术后6个月的JOA评分、ODI差值比较,差异均无统计学意义(P>0.05)。两组术前、术后6个月的伤椎前后缘高度比差值、后凸Cobb角差值、外旋活动度差值比较,差异均无统计学意义(P>0.05)。两组并发症总发生率比较,差异无统计学意义(P>0.05)。结论 无神经症状的腰椎骨折患者C型臂与G型臂激光定位透视下行经皮椎弓根螺钉置入均可获得满意疗效,但G型臂激光定位透视可减少透视次数,缩短手术时间,且透视精准率、螺钉植入准确度更高。

数字减影血管造影引导下幽门球囊扩张术治疗术后胃瘫优于内科保守治疗

目的 比较数字减影血管造影(DSA)引导下幽门球囊扩张术与内科保守治疗治疗术后胃瘫(PGS)的临床疗效。方法 对2012年1月至2021年2月在苏州大学附属第三医院介入放射科实施幽门球囊扩张术与内科保守治疗的41例术后胃瘫患者的临床资料展开回顾性分析。在中位随访时间上,对照组、试验组各是626 d、588 d。两组的平均住院天数(ALOS)进行比较。结果 试验组21例患者在DSA引导下行幽门球囊扩张术治疗后的2 d内,均恢复正常进食,1周内全部出院。试验组(10.2±1.3)d的ALOS明显短于对照组的(34.5±14.2) d,且具有统计学差异(P<0.001)。结论 与内科保守治疗相比,DSA引导下幽门球囊扩张术治疗PGS疗效显著,可以作为PGS患者的首选治疗方法。但作用机制尚不明确,有待进一步研究。

根据首诊影像学表现构建模型预测低级别膝关节软骨下功能不全性骨折进展

目的根据膝关节软骨下功能不全性骨折(SIFK)首诊影像学因素构建模型,预测其进展。方法回顾性分析60例低级别(1级或2级)SIFK患者,根据1年后SIFK分级将其分为进展组(进展为3级或4级,n=30)及无进展组(仍为1级或2级,n=30);比较2组首诊临床及影像学资料。根据组间差异有统计学意义的首诊影像学表现建立多因素logistic回归模型,预测低级别SIFK进展;绘制受试者工作特征曲线,计算曲线下面积(AUC),评价模型预测价值,并与单一预测因素进行比较。结果组间胫骨内翻角、胫骨后倾角(PTS)、病变髁软骨损伤分级、内侧半月板挤压距离、内侧半月板后角根部损伤及撕裂类型差异均有统计学意义(P均<0.05)。根据首诊影像学所见PTS、病变髁软骨损伤分级和内侧半月板挤压距离构建的预测低级别SIFK进展的回归模型为Logit(P)=-0.561+0.300×PTS(°)+1.702×病变髁软骨损伤分级+0.874×内侧半月板挤压距离(mm),其AUC为0.962,高于任意单一预测因素(P均<0.05)。结论根据首诊影像学所见PTS、病变髁软骨损伤分级和内侧半月板挤压距离构建的回归模型预测低级别SIFK进展的价值良好。

X线透视指导下猪心房间隔穿刺方法的探讨

目的探讨X线透视指导下猪心房间隔穿刺的标准化流程和方法,提高房间隔穿刺的安全性和有效性。方法在X线透视指导下对48只浦东白猪进行房间隔穿刺,房间隔穿刺点的定位条件:(1)穿刺点高度为后前位透视下沿脊柱中线冠状静脉窦(CS)口上1个椎体高度;(2)以10°为间隔,按照右前斜10°~60°和左前斜10°~60°完成对CS导管的透视,可以判断CS 5-6和7-8电极的连线为垂直于卵圆窝的关系,确认CS 5-6和7-8电极在同一直线上的透视角度;(3)在此透视角度下,调整房间隔穿刺针及鞘管远段弧度消失呈直线状或接近直线状。结果成功对48只浦东白猪进行房间隔穿刺,无并发症发生,术后超声心动图证实房间隔有左向右分流,房间隔穿刺平均手术用时(25.7±11.5)min,平均X线曝光时间(14.0±3.4)min,平均辐射剂量(47.6±20.2)mGy。结论以CS电极为参考,X线透视指导下行猪心房间隔穿刺安全可靠。

Safety of endoscopic retrograde cholangiopancreatography in pregnancy: Fluoroscopy time and fetal exposure, does it matter?

AIM: To estimate the fetal radiation exposure using thermoluminescent dosimeters (TLD's) in pregnant patients undergoing endoscopic retrograde cholangiopancreatography (ERCP) and assess its relevance. METHODS: Data on thirty-five therapeutic ERCPs conducted in pregnant patients from 2001 to 2009 were retrieved from a prospective database. Techniques to minimize fluoroscopy time were implemented and the fluoroscopy times captured. TLD's were placed on the mother to estimate the fetal radiation exposure and the results were compared to the maximum allowed dose of radiation to the fetus [0.005 gray (Gy)]. Obstetrics consultations were obtained and the fetus was monitored before and after the ERCP. Fluoroscopy wasperformed at 75 kVp. ERCP was performed with the patients supine by dedicated biliary endoscopists performing more than 500 cases a year. RESULTS: A total of 35 pregnant patients underwent ERCP and biliary sphincterotomy (14 in first trimester, 11 in second trimester, and 10 in third trimester). Mean maternal age was 25 years (range 16-37 years) and mean gestational age was 18.9 wk (range 4-35 wk). Mean fluoroscopy time was 0.15 min (range 0-1 min). For 23 women, the estimated fetal radiation exposure was almost negligible (< 0.0001 Gy) while for 8 women, it was within the 0.0001-0.0002 Gy range. Three women had an estimated fetal radiation exposure between 0.0002 and 0.0005 Gy and 1 woman had an estimated fetal radiation exposure greater than 0.0005 Gy. Complications included 2 post-sphincterotomy bleeds, 2 post-ERCP pancreatitis, and 1 fatal acute respiratory distress syndrome. One patient developed cholecystitis 2 d after ERCP. CONCLUSION: ERCP with modified techniques is safe during pregnancy, and estimating the fetal radiation exposure from the fluoroscopy time or measuring it via TLD's is unnecessary.

Fluoroscopy guided percutaneous renal access in prone position

Percutaneous nephrolithotomy is a very commonly done procedure for management of renal calculus disease. Establishing a good access is the first and probably themost crucial step of this procedure. A proper access is the gateway to success. However, this crucial step has the steepest learning curve for, in a fluoroscopy guided access, it involves visualizing a three dimensional anatomy on a two dimensional fluoroscopy screen. This review describes the anatomical basis of the renal access. It provides a literature review of all aspects of percutaneous renal access along with the advances that have taken place in this field over the years. The article describes a technique to determine the site of skin puncture, the angle and depth of puncture using a simple mathematical principle. It also reviews the common problems faced during the process of puncture and dilatation and describes the ways to overcome them. The aim of this article is to provide the reader a step by step guide for percutaneous renal access.

Augmented reality: The use of the PicoLinker smart glasses improves wire insertion under fluoroscopy

AIM To demonstrate the feasibility of the wearable smart glasses, Pico Linker, in guide wire insertion under fluoroscopic guidance. METHODS Under a fluoroscope, a surgeon inserted 3 mm guide wires into plastic femurs from the lateral cortex to the femoral head center while the surgeon did or did not wear Pico Linker, which are wearable smart glasses where the fluoroscopic video was displayed(10 guide wires each). RESULTS The tip apex distance, radiation exposure time and total insertion time were significantly shorter while wearing the Pico Linker smart glasses. CONCLUSION This study indicated that the Pico Linker smart glasses can improve accuracy, reduce radiation exposure time, and reduce total insertion time. This is due to the fact that the Pico Linker smart glasses enable surgeons to keep their eyes on the operation field.

Impaired swallowing mechanics of post radiation therapy head and neck cancer patients: A retrospective videofluoroscopic study

AIM: To determine swallowing outcomes and hyolaryngeal mechanics associated with post radiation therapy head and neck cancer(rt HNC) patients using videofluoroscopic swallow studies. METHODS: In this retrospective cohort study, video-fluoroscopic images of rt HNC patients(n = 21) were compared with age and gender matched controls(n = 21). Penetration-aspiration of the bolus and bolus residue were measured as swallowing outcome variables. Timing and displacement measurements of the anterior and posterior muscular slings elevating the hyolaryngeal complex were acquired. Coordinate data of anatomical landmarks mapping the action of the anterior muscles(suprahyoid muscles) and posterior muscles(long pharyngeal muscles) were used to calculate the distance measurements, and slice numbers were used to calculate time intervals. Canonical variate analysis with post-hoc discriminant function analysis was performed on coordinate data to determine multivariate mechanics of swallowing associated with treatment. Pharyngeal constriction ratio(PCR) was also measured to determine if weak pharyngeal constriction is associated with post radiation therapy.RESULTS: The rt HNC group was characterized by poor swallowing outcomes compared to the control group in regards to: Penetration-aspiration scale(P < 0.0001), normalized residue ratio scale(NRRS) for the valleculae(P = 0.002) and NRRS for the piriform sinuses(P = 0.003). Timing and distance measurements of the anterior muscular sling were not significantly different in the two groups, whereas for the PMS time of displacement was abbreviated(P = 0.002) and distance of excursion was reduced(P = 0.02) in the rt HNC group. A canonical variate analysis shows a significant reduction in pharyngeal mechanics in the rt HNC group(P < 0.0001). The PCR was significantly higher in the test group than the control group(P = 0.0001) indicating reduced efficiency in pharyngeal clearance. CONCLUSION: Using videofluoroscopy, this study shows rt HNC patients have worse swallowing outcomes associated with reduced hyolaryngeal mechanics and pharyngeal constriction compared with controls.

Correlation analysis of dual-energy CT iodine maps with quantitative pulmonary perfusion MRI

AIM:To correlate dual-energy computed tomography(DECT) pulmonary angiography derived iodine maps with parameter maps of quantitative pulmonary perfusion magnetic resonance imaging(MRI).METHODS:Eighteen patients with pulmonary perfusion defects detected on DECT derived iodine maps were included in this prospective study and additionally underwent time-resolved contrast-enhanced pulmonary MRI [dynamic contrast enhanced(DCE)-MRI].DCE-MRI data were quantitatively analyzed using a pixel-by-pixel deconvolution analysis calculating regional pulmonary blood flow(PBF),pulmonary blood volume(PBV) and mean transit time(MTT) in visually normal lung parenchyma and perfusion defects.Perfusion parameterswere correlated to mean attenuation values of normal lung and perfusion defects on DECT iodine maps.Two readers rated the concordance of perfusion defects in a visual analysis using a 5-point Likert-scale(1 = no correlation,5 = excellent correlation).RESULTS:In visually normal pulmonary tissue mean DECT and MRI values were:22.6 ± 8.3 Hounsfield units(HU);PBF:58.8 ± 36.0 mL/100 mL per minute;PBV:16.6 ± 8.5 mL;MTT:17.1 ± 10.3 s.In areas with restricted perfusion mean DECT and MRI values were:4.0 ± 3.9 HU;PBF:10.3 ± 5.5 mL/100 mL per minute,PBV:5 ± 4 mL,MTT:21.6 ± 14.0 s.The differences between visually normal parenchyma and areas of restricted perfusion were statistically significant for PBF,PBV and DECT(P < 0.0001).No linear correlation was found between MRI perfusion parameters and attenuation values of DECT iodine maps(PBF:r = 0.35,P = 0.15;PBV:r = 0.34,P = 0.16;MTT:r = 0.41,P = 0.08).Visual analysis revealed a moderate correlation between perfusion defects on DECT iodine maps and the parameter maps of DCE-MRI(mean score 3.6,k 0.45).CONCLUSION:There is a moderate visual but not statistically significant correlation between DECT iodine maps and perfusion parameter maps of DCE-MRI.

Comparative Analysis of the Multi-Frequency Bio-impedance and Dual-energy X-ray Absorptiometry on Body Composition in Obese Subjects

To examine accuracy of body composition predicted by the Multi-Frequency Bioelectric Impedance Analysis （MF-BIA） compared with the Dual-energy X-ray Absorptiometry （DXA） in adults with obese. We measured body composition of 749 adults with obese both by the MF-BIA and DXA. The Lin＇s concordance correlation and the Bland-Altman plots were used to examine the consistency. The concordance correlation coefficient of %BF between the MF-BIA and DXA in men and women was 0.560, and 0.669, respectively. Compared with the DXA, the MF-BIA significantly underestimated %BF by 4.33% in men （P 〈 0.001）, however overestimated %BF by 0.50% in women （P 〈 0.001）. After corrected by the correction equations established in this study, the differences were significantly decreased. Therefore, the MF-BIA （TANITA MC-180） may need to be corrected in estimating body composition for adults with obese.

Determinants of Detection of Stones and Calcifications in the Hepatobiliary System on Virtual Nonenhanced Dual-energy CT

Objective To retrospectively determine the features of stones and calcifications in hepatobiliary system on virtual nonenhanced(VNE) dual-energy computed tomography(CT), and to evaluate the possibility of VNE images in diagnosis for those lesions. Methods A total of 128 gall stones and calcifications of the liver found in 110 patients were examined with triple phase abdominal CT scan from July 2007 to December 2011, in which true nonenhanced(TNE) phase and arterial phase were performed with single-energy CT(120 kVp) and portal venous phase was performed with dual-energy CT(100 kVp and 140 kVp). VNE images were generated from the portal venous phase dual-energy CT data sets by using commercially VNC software. The mean CT values for the stone, liver, bile and paraspinal muscle, mean lesion density and size in area dimension, contrast-to-noise ratio(CNR) of lesion to the liver or bile, and image noise were assessed and compared between VNE and TNE images. The effective dose and size-specific dose estimate(SSDE) were also calculated. Results The mean CT values of the lesions measured on VNE images declined significantly compared with those measured on TNE images(164.51±102.13 vs. 290.72±197.80 HU, P<0.001), so did the lesion-to-liver CNR(10.80±11.82 vs.18.81±17.06, P<0.001) and the lesion-to-bile CNR(17.24±14.41 vs. 21.32±17.31, P<0.001). There was no significant difference in size of lesions area between VNE and TNE images(0.69±0.88 vs. 0.72±0.85 cm2, P=0.062). Compared to the 128 lesions found in TNE images, VNE images showed the same density in 30(23.4%) lesions, lighter density in 88(68.8%) lesions, while failed to show 10(7.8%) lesions, and showed the same size in 61(47.7%) lesions and smaller size in 57(44.5%)lesions. The CT cutoff values of lesion and size were 229.21 HU and 0.15 cm2, respectively. The total effective dose for triple phase scan protocol with TNE images was 19.51±7.03 mS v, and the SSDE was 39.84±11.10 mGy. The effective dose for dual phase scan protocol with VNE images instead of TNE images was 13.29±4.89 m Sv, and the SSDE was 27.83±9.99 mGy. Compared with TNE images, the effective dose and SSDE of VNE images were down by 32.05%±3.69 % and 30.63%±2.34 %, respectively. Conclusions Although the CT values and CNR of the lesions decreased in VNE images, the lesions of which attenuation greater than 229.21 HU and size larger than 0.15 cm^2 could be detected with good reliability and obvious dose reduction. There was good consistency in the size of stones and calcifications in hepatobiliary system between VNE images and TNE images, which ensured the possibility of the clinical application of VNE images.

Characterization of ureteral stents by dual-energy computed tomography: Clinical implications

Dual-energy computed-tomography(DECT) has been suggested as the method of choice for imaging urinary calculi due to the modality's high sensitivity for detect-ing stones and its capability of accurately differentiat-ing between uric-acid(UA) and non-UA(predominantly calcium) stones. The clinical significance of the latter feature relates to the differences in management of UA vs non-UA calculi. Like calculi, ureteral stents are assigned color by the dual-energy post-processing algorithm, which may lead to improved or worsened stone visualization based on the resulting stent/stone contrast. Herein we depict the case of a nephrolithiasis patient with bilateral stents, each with different color, clearly displaying the effect of stent color on stone vi-sualization. Further, three-dimensional reconstruction of the DECT images illustrates advantages of this enhancement compared to conventional two-dimensional computed tomography. The resulting stent/stone contrast produces an unanticipated potential advantage of DECT in patients with urolithiasis and stents and may promote improved management decision-making.

Immediate detection of endoscopic retrograde cholangiopancreatographyrelated periampullary perforation: Fluoroscopy or endoscopy?

AIM:To investigate the causes and intraoperative detection of endoscopic retrograde cholangiopancreatography(ERCP)-related perforations to support immediate or early diagnosis.METHODS:Consecutive patients who underwent ERCP procedures at our hospital between January2008 and June 2013 were retrospectively enrolled in the study(n=2674).All procedures had been carried out using digital fluoroscopic assistance with the patient under conscious sedation.For patients showing alterations in the gastrointestinal anatomy,a short-type double balloon enteroscope had been applied.Cases of perforation had been identified by the presence of air in or leakage of contrast medium into the retroperitonealspace,or upon endoscopic detection of an abdominal cavity related to the perforated lumen.For patients with ERCP-related perforations,the data on medical history,endoscopic findings,radiologic findings,diagnostic methods,management,and clinical outcomes were used for descriptive analysis.RESULTS:Of the 2674 ERCP procedures performed during the 71-mo study period,only six(0.22%)resulted in perforations(male/female,2/4;median age:84 years;age range:57-97 years).The cases included an endoscope-related duodenal perforation,two periampullary perforations related to endoscopic sphincterotomy,two periampullary perforations related to endoscopic papillary balloon dilation,and a periampullary or bile duct perforation secondary to endoscopic instrument trauma.No cases of guidewire-related perforation occurred.The video endoscope system employed in all procedures was only able to immediately detect the endoscope-related perforation;the other five perforation cases were all detected by subsequent digital fluoroscope applied intraoperatively(at a median post-ERCP intervention time of 15 min).Three out of the six total perforation cases,including the single case of endoscope-related duodenal injury,were surgically treated;the remaining three cases were treated with conservative management,including trans-arterial embolization to control the bleeding in one of the cases.All patients recovered without further incident.CONCLUSION:ERCP-related perforations may be difficult to diagnose by video endoscope and digital fluoroscope detection of retroperitoneal free air or contrast medium leakage can facilitate diagnosis.

Quantitative dual-energy computed tomography texture analysis predicts the response of primary small hepatocellular carcinoma to radiofrequency ablation

Background:Radiofrequency ablation(RFA)is one of the effective therapeutic modalities in patients with hepatocellular carcinoma(HCC).However,there is no proper method to evaluate the HCC response to RFA.This study aimed to establish and validate a clinical prediction model based on dual-energy com-puted tomography(DECT)quantitative-imaging parameters,clinical variables,and CT texture parameters.Methods:We enrolled 63 patients with small HCC.Two to four weeks after RFA,we performed DECT scanning to obtain DECT-quantitative parameters and to record the patients’clinical baseline variables.DECT images were manually segmented,and 56 CT texture features were extracted.We used LASSO al-gorithm for feature selection and data dimensionality reduction;logistic regression analysis was used to build a clinical model with clinical variables and DECT-quantitative parameters;we then added texture features to build a clinical-texture model based on clinical model.Results:A total of six optimal CT texture analysis(CTTA)features were selected,which were statis-tically different between patients with or without tumor progression(P<0.05).When clinical vari-ables and DECT-quantitative parameters were included,the clinical models showed that albumin-bilirubin grade(ALBI)[odds ratio(OR)=2.77,95%confidence interval(CI):1.35-6.65,P=0.010],λAP(40-100 keV)(OR=3.21,95%CI:3.16-5.65,P=0.045)and IC AP(OR=1.25,95%CI:1.01-1.62,P=0.028)were asso-ciated with tumor progression,while the clinical-texture models showed that ALBI(OR=2.40,95%CI:1.19-5.68,P=0.024),λAP(40-100 keV)(OR=1.43,95%CI:1.10-2.07,P=0.019),and CTTA-score(OR=2.98,95%CI:1.68-6.66,P=0.001)were independent risk factors for tumor progression.The clinical model,clinical-texture model,and CTTA-score all performed well in predicting tumor progression within 12 months after RFA(AUC=0.917,0.962,and 0.906,respectively),and the C-indexes of the clinical and clinical-texture models were 0.917 and 0.957,respectively.Conclusions:DECT-quantitative parameters,CTTA,and clinical variables were helpful in predicting HCC progression after RFA.The constructed clinical prediction model can provide early warning of potential tumor progression risk for patients after RFA.

Diagnostic Value of Dual-Energy CT in Differentiating Malignant and Benign Thyroid Nodules: A Systematic Review and Meta-Analysis

Objectives: To evaluate the diagnostic performance of the quantitative iodine parameters, including Iodine Concentration (IC), Normalized Iodine Concentration (NIC), and λHU, in distinguishing malignant and benign thyroid nodules. Methods: Relevant studies were searched from Web of Science, PubMed, Embase, Cochrane Library, China National Knowledge Infrastructure database and other complementary sources from inception to May 20, 2020. Study selection, data extraction, quality assessment, and data analyses were performed following the Cochrane standards and the PRISMA-DTA guideline. Results: Eight studies were included (595 patients with 737 thyroid nodules). The pooled sensitivity, specificity and summary diagnostic odds ratio of IC were 79% (95% CI: 69% - 86%), 76% (95% CI: 65% - 84%) and 11 (95% CI: 5 - 27) respectively;those of NIC were 78% (95% CI: 70% - 85%), 80% (95% CI: 74% - 85%) and 15 (95% CI: 9 - 24) respectively;those of λHU were 80% (95% CI: 71% - 87%), 77% (95% CI: 70% - 83%) and 14 (95% CI: 8 - 24) respectively. Conclusion: DECT can be a potential evaluation tool for thyroid nodules. The NIC may be the most sensitive iodine parameter and could be comparable between different DECT machines in thyroid nodule assessment.