高场强MR对脊膜瘤的诊断价值

目的 通过高场强MR对脊膜瘤的表现特征进行分析 ,探讨MR对脊膜瘤的诊断价值。方法 经手术病理证实脊膜瘤 18例 ,所有病例均采用Siemens 6 3SP型 1.5T超导型磁共振扫描仪的自旋回波T1加权及T2加权序列进行扫描 ,常规行矢状位扫描 ,必要时加扫轴位和 /或冠状位。所有病例均通过MR图像对肿瘤的部位、形态、大小、边界、信号、是否发生坏死囊变、椎间孔改变及增强后强化情况各方面进行观察分析。结果 18例脊膜瘤中发生于颈椎6例、胸椎 12例 ,肿瘤位于脊髓前方 9例 ,位于脊髓后方 2例 ,偏右侧 4例 ,偏左侧 3例。肿瘤呈圆形 11例 ,病灶直径平均为 1.89cm ,病灶内信号均匀 13例 ,略不均匀 5例 ,T1加权图像呈等信号 17例 ,略短信号 1例 ,T2加权图像呈等信号 9例 ,略长信号 9例 ,明显均匀强化 14例。结论 脊膜瘤在MR图像上具有诸多的特征性表现 。

Bezoar-induced small bowel obstruction: Clinical characteristics and diagnostic value of multi-slice spiral computed tomography

AIM: To determine the possible predisposing factors of bezoar-induced small bowel obstruction(b I-Sb O) and to discuss the diagnostic value of multi-slice spiral computed tomography,particularly contrast-enhanced scanning,in this condition.METHODS: A total of 35 b I-Sb O cases treated at our hospital from January 2007 to December 2013 were retrospectively analysed.Complete clinical and computed tomography(CT) data of the patients were available and confirmed by surgery.SbO was clinically diagnosed on the basis of clinical manifestations.Of the 35 patients,18 underwent abdominal and pelvic CT planar scanning with GE 64-slice spiral CT and 17 underwent abdominal and pelvic CT planar scanning with GE 64-slice spiral CT combined with contrastenhanced examination.Original images were processed using a GE ADW4.3 workstation to obtain MPR,CPR,MIP and CTA images.The images of all patients were evaluated by two abdominal imaging experts.The main analytical contents of planar scanning included intestinal bezoar conditions,changes in the intestinal wall and changes in peri-intestinal conditions.Vascular hyperaemia and arterial blood supply conditions at a specific obstruction site and the distal end of the obstruction site were evaluated through contrastenhanced examination.RESULTS: The proportion of males to females among the 35 cases was 1:1.69(13:22); median age was 63.3 years.The following cases were observed: 29(82.8%) cases occurred in autumn and winter and showed a history of consuming high amounts of persimmon and hawthorn; 19(54.3%) cases revealed a history of gastrointestinal surgery; 19 exhibited incomplete dentition,with missing partial or whole posterior teeth; 26 suffered from obstruction at the ileum.A total of 51 bezoars were found in these patients,of whom 16(45.7%) had multiple bezoars.CT planar scanning of bezoars showed lumps with mottled gas inside the intestinal cavity.Furthermore,9 cases of bezoars had envelopes and 11 cases were accompanied with thickening of the distal wall of the obstructed bowel.Scanning of 17 cases was enhanced; the results revealed that the mesenteric blood vessels at the obstruction site and the proximal site were dilated,and a total of 7 cases were accompanied with distal vascular dilation and intestinal wall thickening.CONCLUSION: b I-Sb O exhibits regional and seasonal characteristics.CT planar and contrast-enhanced scanning can be applied to diagnose and observe vascular conditions in obstructed zones.

Perfusion CT findings in liver of patients with tumor during chemotherapy

AIM: To investigate the microcirculation changes in liver of patients with tumor during chemotherapy by perfusion computed tomography (CT). METHODS: Sixty patients with tumor and 20 controls were enrolled in this study. Perfusion CT parameters of patients and controls were compared, including hepatic perfusion index (HPI), mean transit time (MTT), and permeability-surface area product (PS). Correlation between perfusion CT parameters, treatment cycle and alanine aminotransferase (ALT) level was studied. RESULTS: No difference was found in HPI (25.68% ± 7.38% vs 26.82% ± 5.13%), MTT (19.67 ± 5.68 s vs21.70 ± 5.43 s) and PS (17.00 ± 4.56 mL/100 mL per min vs 19.92 ± 6.35 mL/100 mL per min) between pa- tients and controls. The HPI and MTT were significantly higher in patients undergoing 2 cycles of chemotherapy than in controls and those undergoing 1 cycle of che- motherapy (29.76% ± 5.87% vs 25.68% ± 7.38% and 25.35% ± 4.05%, and 25.61 ± 5.01 s vs 19.67 ± 5.68 s and 19.74 ± 4.54 s, respectively, P < 0.05). The HPI was higher in patients with hepatic steatosis than in controls and those without hepatic steatosis (30.85% ± 6.17% vs 25.68% ± 7.38% and 25.70% ± 4.24%, P < 0.05). Treatment cycle was well correlated with HPI and MTT (r = 0.40, r = 0.50, P < 0.01). ALT level was not correlated with perfusion CT parameters. CONCLUSION: HPI and MTT are significantly increased in patients with tumor during chemotherapy and well correlated with treatment cycle. Chemotherapy affects hepatic microcirculation in patients with tumor. Changes in hepatic microcirculation can be quantitatively assessed by perfusion CT.

1.0 T开放式MRI扫描设备实时引导下脑活检

目的评价1.0 T开放式MRI实时引导下脑活检的安全性、可行性及诊断价值。方法86例病人在1.0 T开放式MRI实时引导及MR透视技术下行脑穿刺活检,并回顾性分析其临床资料。

Clinicopathological characteristics and surgical outcomes of sarcomatoid hepatocellular carcinoma

BACKGROUND Hepatocellular carcinoma(HCC)is the sixth most common type of cancer and the fourth leading cause of cancer-related death worldwide.Sarcomatoid HCC,which contains poorly differentiated carcinomatous and sarcomatous components,is a rare histological subtype of HCC that differs from conventional HCC.It is highly aggressive and has a poor prognosis.Its clinicopathological characteristics,surgical outcomes and underlying mechanisms of its highly aggressive nature have not been fully elucidated.AIM To examine the clinicopathological characteristics and surgical outcomes of sarcomatoid HCC and explore the histogenesis of sarcomatoid HCC.METHODS In total,196 patients[41 sarcomatoid HCC and 155 high-grade(Edmondson-Steiner grade III or IV)HCC]who underwent surgical resection between 2007 and 2017 were retrospectively reviewed.The characteristics and surgical outcomes of sarcomatoid HCC were compared with those of patients with high-grade HCC.The histological composition of invasive and metastatic sarcomatoid HCCs was evaluated.RESULTS Sarcomatoid HCC was more frequently diagnosed at an advanced stage with a larger tumor and higher rates of nonspecific symptom,adjacent organ invasion and lymph node metastasis than high-grade HCC(all P<0.05).Compared with high-grade HCC patients,sarcomatoid HCC patients are less likely to have typical dynamic imaging features of HCC(44.4%vs 72.7%,P=0.001)and elevated serum alpha-fetoprotein levels(>20 ng/mL;36.6%vs 78.7%,P<0.001).The sarcomatoid group had a significantly shorter median recurrence-free survival(5.6 mo vs 16.4 mo,log-rank P<0.0001)and overall survival(10.5 mo vs 48.1 mo,log-rank P<0.0001)than the high-grade group.After controlling for confounding factors,the sarcomatoid subtype was identified as an independent predictor of poor prognosis.Pathological analyses indicated that invasive and metastatic lesions were mainly composed of carcinomatous components.CONCLUSION Sarcomatoid HCC was associated with a more advanced stage,atypical dynamic imaging,lower serum alpha-fetoprotein levels and a worse prognosis.The highly aggressive nature of sarcomatoid HCC is perhaps mediated by carcinomatous components.

Abnormal resting-state functional network centrality in patients with high myopia： evidence from a voxel-wise degree centrality analysis

AIM： To investigate the functional networks underlying the brain-activity changes of patients with high myopia using the voxel-wise degree centrality（DC） method.METHODS： In total, 38 patients with high myopia（HM）（17 males and 21 females）, whose binocular refractive diopter were-6.00 to-7.00 D, and 38 healthy controls（17 males and 21 females）, closely matched in age, sex, and education levels, participated in the study. Spontaneous brain activities were evaluated using the voxel-wise DC method. The receiver operating characteristic curve was measured to distinguish patients with HM from healthy controls. Correlation analysis was used to explore the relationship between the observed mean DC values of the different brain areas and the behavioral performance.RESULTS： Compared with healthy controls, HM patients had significantly decreased DC values in the right inferior frontal gyrus/insula, right middle frontal gyrus, and right supramarginal/inferior parietal lobule（P〈0.05）. In contrast, HM patients had significantly increased DC values in the right cerebellum posterior lobe, left precentral gyrus/postcentral gyrus, and right middle cingulate gyrus（P〈0.05）. However, no relationship was found between the observed mean DC values of the different brain areas and the behavioral performance（P〉0.05）.CONCLUSION： HM is associated with abnormalities in many brain regions, which may indicate the neural mechanisms of HM. The altered DC values may be used as a useful biomarker for the brain activity changes in HM patients.

Epithelioid angiomyolipoma of the pancreas:A case report and review of the literature

BACKGROUND Angiomyolipomas(AMLs),belonging to the family of mesenchymal tumors,are considered benign lesions that occur mostly in the kidney or as a part of tuberous sclerosis.Epithelioid AML(EAML)is a rare type of AML that appears to have malignant potential.Extrarenal AMLs usually occur in the liver according to the retrieved literature reports.There have been only two previous reports of monofocal primary AML of the pancreas;however,no cases of primary monotypic EAML of the pancreas have been reported.CASE SUMMARY An asymptomatic 59-year-old woman incidentally revealed a tumor during abdominal ultrasound examination.Routine blood tests and physical examination were within normal limits.Abdominal ultrasound revealed a 1.9-cm hypoechogenic mass in the tail of the pancreas,clearly visualized by endoscopic ultrasound.However,contrast-enhanced abdominal computed tomography scans did not demonstrate the lesion.A subsequent gadolinium-enhanced magnetic resonance imaging scan showed that the lesion had some characteristic manifestations.The lesion was initially thought to be a neuroendocrine tumor(asymptomatic PanNET).After surgical resection,histopathology and immunohistochemistry confirmed the diagnosis of EAML.At the 6-mo follow-up,no recurrence,spread,or metastasis was identified on computed tomography or magnetic resonance imaging.CONCLUSION The preoperative diagnosis of pancreatic AML is extremely difficult.Imaging techniques are essential for providing valuable morphological features for differential diagnosis.

Early- and intermediate-term outcome of transarterial embolization for symptomatic hepatic focal nodular hyperplasia

Purpose: To evaluate the early-and intermediate-term outcome in patients with symptomatic hepatic focal nodular hyperplasia(FNH) treated with transarterial embolization using bleomycin-iodinated oil and polyvinyl alcohol(PVA) particles. Materials and methods: In this two-center retrospective study between January 2005 and December 2013, 27 consecutive patients with symptomatic hepatic FNH underwent superselective catheterization by microcatheter techniques and embolization using bleomycin-iodinated oil combined with PVA. Early-term(3–41 months) follow-up of TAE was performed in terms of symptom control, changes in lesion size, and complications. Intermediate-term(45–112 months) follow-up was carried out to assess symptom control and reinterventions for recurrence. Results: Embolization was performed in 27 patients with 31 lesions. Technical success was achieved in all cases. The follow-up period ranged from three to 112 months. At early-term follow-up, mean lesion diameters were decreased significantly from 6.4±2.7 cm pre-intervention to 3.6±1.8 cm at 3-9 months after embolization(P<0.001). A total of 7 lesions had complete resolution during the whole follow-up period. At intermediate-term follow-up, local recurrence was found in 1 treated lesion at 54-months. Contrast-enhanced scans showed complete lack of residual arterial blood supply in the majority of lesions during the follow-up period. There was no major complication associated with the procedure. Conclusion: Transarterial embolization using bleomycin-iodinated oil and PVA is a feasible, safe and effective alternative in both early-and intermediate-terms for the treatment of symptomatic hepatic FNH.

A modified wire-loop snare technique for the retrieval of a large cardiac cement embolus caused by cement leakage after percutaneous vertebroplasty

Percutaneous vertebroplasty(PVP) is an interventional radiological procedure involving the injection of bone cement(polymethylmethacrylate) into a fractured vertebral body to remodel the vertebral body and relieve lumbar pain.

Recombinant adeno-associated virus delivered human thioredoxin-PR39 prevents hypoxia-induced apoptosis of ECV304 cells

Human thioredoxin and antibacterial peptide, PR39, have been shown to have potent antioxidant effects that may prolong survival of cells during hypoxia. The pSSCMV/human thioredoxin-PR39 vector was successfully constructed in this study and used to infect ECV304 cells. Transfected ECV304 cells were incubated at 1%, 5% hypoxic, and normal oxygen conditions. We found that the number of apoptotic cells after transfection with recombinant adeno-associated virus-human thioredoxin -PR39 was significantly lower than controls, suggesting a protective effect of the recombinant human thioredoxin-PR39 protein on hypoxic cells.

Development of an Ultrasonic Nomogram for Preoperative Prediction of Castleman Disease Pathological Type

An ultrasonic nomogram was developed for preoperative prediction of Castleman disease(CD)pathological type(hyaline vascular(HV)or plasma cell(PC)variant)to improve the understanding and diagnostic accuracy of ultrasound for this disease.Fifty cases of CD confirmed by pathology were gathered from January 2012 to October 2018 from three hospitals.A grayscale ultrasound image of each patient was collected and processed.First,the region of interest of each gray ultrasound image was manually segmented using a process that was guided and calibrated by radiologists who have been engaged in imaging diagnosis for more than 5 years.In addition,the clinical characteristics and other ultrasonic features extracted from the color Doppler and spectral Doppler ultrasound images were also selected.Second,the chi-square test was used to select and reduce features.Third,a naïve Bayesian model was used as a classifier.Last,clinical cases with gray ultrasound image datasets from the hospital were used to test the performance of our proposed method.Among these patients,31 patients(18 patients with HV and 13 patients with PC)were used to build a training set for the predictive model and 19(11 patients with HV and 8 patients with PC)were used for the test set.From the set,584 high-throughput and quantitative image features,such as mass shape size,intensity,texture characteristics,and wavelet characteristics,were extracted,and then 152 images features were selected.Comparing the radiomics classification results with the pathological results,the accuracy rate,sensitivity,and specificity were 84.2%,90.1%,and 87.5%,respectively.The experimental results show that radiomics was valuable for the differentiation of CD pathological type.

Voxel Placement Precision for GABA-Edited Magnetic Resonance Spectroscopy

The purpose of the present study was to assess the reproducibility of voxel placement for GABA-edited MRS. GABA-edited MRS data were acquired in 13 healthy volunteers from (3 cm)3 voxel;and within the same session a second acquisition was independently prescribed. A three-dimensional voxel mask image was reconstructed in T1-image-space using the SVMask tool (in house software). Reproducibility of voxel placement was assessed using the Dice overlap coefficient, both within-subject and between-subject following co-registration of T1 images and transformation of voxel mask images to standard space. Within-subject overlap coefficients were 86% ± 5%. Between-subject overlap coefficients were 75% ± 10%. For the two voxel locations considered (occipital and sensorimotor), voxel overlap was very similar. Between-subject values are higher due to between-session effects, anatomical variability and volume mismatch in standard space. While surprisingly low in terms of volume overlap, the overlap coefficients correspond to acceptable linear displacements.

Fetal central nervous system anomalies: comparison of magnetic resonance imaging and ultrasonography for diagnosis

Background Evaluation of fetal central nervous system （CNS） agenesis by ultrasonography （US） is frequently limited, but magnetic resonance imaging （MRI） has its own advantages and is gaining popularity in displaying suspected fetal anomalies. The purpose of this study was to explore the value of MRI in detecting fetal CNS agenesls. Methods Thirty-four women （aged from 22 to 35 years, average 27 years） with complicated pregnancies （16-- 39 weeks of gestation, average 30 weeks） were examined with a 1.5 T superconductive MR unit within 24 hours after ultrasonography. Half-Fourier acquisition single-shot turbo spin-echo （HASTE） T2-weighted imaging （T2WI） sequence were performed in all patients, and fast low angle shot （FLASH） T1-weighted imaging （T1WI） sequence were applied sequentially in seven of them. Comparison of the results was made between the MRI and US findings as well as autopsy or postnatal follow-up MRI findings. Results The gyms, sulcus, corpus callosum, thalamus, cerebellum, brainstem, and spinal cord of fetus were shown more clearly on T2-weighted MR images than on T1-weighted MR images. MRI corrected the diagnosis of US in 10 cases （10/34, 29.41%） and the diagnosis was missed only in 1 case （1/34, 2.94%）. Conclusion MRI has advantages to US in detecting fetal CNS anomalies and is a supplement to US in complicated pregnancies.

Initial study of biexponential model of intravoxel incoherent motion magnetic resonance imaging in evaluation of the liver fibrosis

Background The diagnosis of liver fibrosis is a difficult task at any time using conventional clinical imaging.Intravoxel incoherent motion （IVIM） can be used to investigate both diffusion and perfusion changes in tissues.This study was designed to determine the value of IVIM in the diagnosis and staging of liver fibrosis.Methods IVIM examinations were performed on a GE 3.0T MR scanner in 25 patients with liver fibrosis and 25 healthy volunteers as the control group.Patients with liver fibrosis diagnosis were confirmed by pathology and staged on a scale of F0-4.The standard ADC values and the values of a biexponential model （slow ADC （Dslow）,fast ADC （Dfast） and fraction of fast ADC （FF）） were measured in three liver regions per person.The mean standard ADC values,Dslow values,Dfast values and FF values from the study group were compared among the right posterior hepatic lobe,right anterior hepatic lobe and medial segment of the left lobe.Receiver Operating Characteristic （ROC） curves and independent-samples t-tests were used to calculate the mean standard ADC values,Dslow values,Dfast values and FF values from the study group and the control group.Spearman rho correlation analysis was used for the stage of liver fibrosis.The liver fibrosis stages between the groups F0-1 and F2-4,the groups F0-2 and F3-4 were compared.Results Among the liver fibrosis,there was no significant difference in the mean standard ADC values,Dslow values,Dfast values,and FF values obtained from the right posterior hepatic lobe,right anterior hepatic lobe and medial segment of the left lobe.Using ROC analysis,the Area Under the Curve （AUC） values of standard ADC,Dslow,Dfast,FF were all between 0.7 to 0.9.The mean standard ADC values,Dslow values,Dfast values and FF values of the liver in the study group were significantly lower than the values in the control group （P ＜0.05）.As the stage of the fibrosis increased,the values decreased by Spearman rho correlation analysis.The mean values （standard ADC,Dslow,Dfast,and FF） of liver fibrosis stages between the groups F0-1 and F2-4,the groups F0-2 and F3-4 showed significant differences （P＜0.05）.Conclusions IVIM can reflect the conditions of perfusion and diffusion in liver fibrosis and thus distinguish between normal liver and liver fibrosis.The IVIM technique may serve as a valuable tool for detecting and characterizing liver fibrosis,and monitoring its progression in a noninvasive manner.

Initial study of magnetic resonance diffusion tensor imaging in brain white matter of early AIDS patients

Background HIV is a neurotropic virus which can cause brain white matter demyelination, gliosis, and other pathological changes that appear as HIV encephalitis or AIDS dementia. The purpose of this study was to investigate the change of the diffused condition of water molecules in brain white matter in early acquired immune deficiency syndrome （AIDS） patients using MR diffusion tensor imaging （DTI）. Methods DTI examinations were performed on a Siemens 3.0T MR scanner in 23 AIDS patients with normal brain appearance by conventional MRI and 20 healthy volunteers as the control group. Fractional anisotropy （FA） and apparent diffusion coefficient （ADC） values were measured in nine regions; corpus callosum （CC） knee, CC body, CC splenium, periventricular white matter, frontal lobe white matter, parietal lobe white matter, occipital lobe white matter, and the anterior and posterior limbs of the internal capsule. The mean FA and ADC values from each region were compared in three groups： the symptomatic, asymptomatic and the control. Results The mean FA values were significantly lower and the mean ADC values were significantly higher in all nine regions in patients in the symptomatic group than in the asymptomatic and control group patients. In the asymptomatic group, the mean FA values were significantly lower and the mean ADC values were significantly higher at the CC knee, CC body, CC splenium, periventricular white matter, frontal lobe white matter and parietal lobe white matter, than in the control group. There were no significant differences at other regions between the two groups. Conclusions The diffused changes of water molecules in brain white matter in AIDS patients are related to brain white matter regions. DTI examination can detect the brain white matter lesions early in AIDS patients.

Relationship Between Clinical and Immunological Features with Magnetic Resonance Imaging Abnormalities in Female Patients with Neuropsychiatric Systemic Lupus Erythematosus

Background：Conventional magnetic resonance imaging （MRI） is the preferred neuroimaging method in the evaluation ofneuropsychiatric systemic lupus erythematosus （NPSLE）.The purpose of this study was to investigate the association between clinical and immunological features with MRI abnormalities in female patients with NPSLE,to screen for the value of conventional MRI in NPSLE.Methods：A total of 59 female NPSLE patients with conventional MRI examinations were enrolled in this retrospective study.All patients were classified into different groups according to MRI abnormalities.Both clinical and immunological features were compared between MRI abnormal and normal groups.One-way analysis of variance was used to compare the systemic lupus erythematosus disease activity index （SLEDAI） score for MRI abnormalities.Multivariate logistic regression analysis investigated the correlation between immunological features,neuropsychiatric manifestations,and MRI abnormalities.Results：Thirty-six NPSLE patients （61%） showed a variety of MRI abnormalities.There were statistically significant differences in SLEDAI scores （P 〈 0.001）,incidence of neurologic disorders （P =0.001）,levels of 24-h proteinuria （P =0.001） and immunoglobulin M （P =0.004）,and incidence of acute confusional state （P =0.002）,cerebrovascular disease （P =0.004）,and seizure disorder （P =0.028） between MRI abnormal and normal groups.In the MRI abnormal group,SLEDAI scores for cerebral atrophy （CA）,cortex involvement,and restricted diffusion （RD） were much higher than in the MRI normal group （P 〈 0.001,P =0.002,P =0.038,respectively）.Statistically significant positive correlations between seizure disorder and cortex involvement （odds ratio [OR] =14.90;95% confidence interval [CI],1.50-151.70;P =0.023） and cerebrovascular disease and infratentorial involvement （OR =10.00;95% CI,1.70-60.00;P =0.012） were found.Conclusions：MRI abnormalities in NPSLE,especially CA,cortex involvement,and RD might be markers of high systemic lupus erythematosus activity.Some MRI abnormalities might correspond to neuropsychiatric manifestations and might be helpful in understanding the pathophysiology of NPSLE.

Comparison of Elastic Properties of Bilateral Carotid Arteries in Relation to Site of Acute Ischemic Stroke Using Velocity Vector Imaging

INTRODUCTIONlschemic stroke accounts for 70% of all the cerebrovascular diseases. Severe stenosis and occlusions ofextracranial and intracranial artery are all important risk factors causing ischemic stroke. Based on the widespread observation worldwide, intracranial atherosclerosis is the most common vascular lesions in Asians, Hispanics, and Africans. Therefore, accurate and noninvasive methods fbr early diagnosis of stroke in individuals without significant stenosis of the extracranial carotid artery is of considerable clinical interest.

Magnetic resonance imaging guided bone biopsies in the iPath-200 system

Objective To study the clinical value of a new MRI compatible percutaneous bone biopsy system.Methods Twenty-six patients with bone lesions MRI-guided biopsies underwent using a 0. 23-T open MR system combined with an iPath-200 optical leading system.Results Of the 26 biopsies, 23 samples were sufficient for histological examination and the histopathologic diagnoses were confirmed. In the high-risk areas like spine, the biopsies were successfully done in 11 patients. No procedural complications occurred.Conclusion Percutaneous biopsy of bone lesions performed under MRI-guidance in an iPath system was proved to be accurate and safe.

Cerebral artery evaluation of dual energy CT angiography with dual source CT

Background Conventional computed tomography angiography （CTA） is time consuming, user-dependent and has poor image quality in skull base region. This study assessed the feasibility of a new method, dual energy CTA for depicting the cerebral artery.Methods Phantom scan was done with head CTA sequences on dual source CT and 64 spiral CT for radiation dose calculation. Dual energy CTA was done with dual source CT on 36 patients who were suspected of having cerebral vascular disease. Three series axial images in 0.75 mm thick, 0.4 mm increment were acquired, which were named with 80 kV, 140 kV and merged images; 80 kV and 140 kV images were transferred into dual energy software, and maximum intensity projection （MIP） image was generated quickly by dual energy bone remove （DEBR group）; merged images were transferred into In Space software to acquire MIP image through manual conventional bone remove （CoBR group）. Post processing time and reading time were compared. Image qualities of the two groups were compared, mainly focusing on skull base segments of internal carotid artery and bone subtraction. ANOVA and SNK tests were applied for radiation dose comparison. Student＇s t test and Wilcoxon rank sum test were applied for assessing differences between data for significance. Cohen＇s kappa was used for interobserver agreement. Results Radiation dose of phantom scan showed dual energy CTA was between digital bone subtraction and conventional CTA. The post processing time and reading time were much shorter in DEBR than CoBR, and image quality in skull base was much higher in DEBR than CoBR （P〈0.01）. There was no significant difference for suprasellar vessels between two groups （P〉0.5）. Interobserver agreement for all vessel segments was excellent （kappa=0.97）. Conclusions Dual energy CTA is a reliable, new modality for depicting cerebral artery, overcoming the limitation of conventional CTA in the skull base region. It can save much time in post processing and reading than conventional CTA.

A new classification of duplex kidney based on kidney morphology and management

Background The initial classic classification of duplex kidney into complete （two ureters） and incomplete （＂Y＂ shaped ureter） types are based on the ureter status. At the meantime, the features of the upper and lower moieties of duplex kidney were very crucial for appropriate procedure of hemi-nephrectomy, which was most commonly used for addressing the issues caused by a duplex kidney; and recently more applications of laparoscopy were used. In this study, we aimed prudently to propose a new classification based on the features of the upper and lower moieties of duplex kidney. Methods Sixty-five children with 83 duplex kidneys were reviewed retrospectively. Based on kidney morphology found in CT urography and surgical findings, duplex kidney was classified into five types. Results The first was the appendant type （36/83） and its feature was that the mini upper moiety was located on top of the lower one, with a visualized shallow groove between them. The ureter was dilated with an ectopic orifice or ureterocele. The second was the embedded type （13/83）, the feature of which was that mini upper moiety located in the interior top of the lower one within the same capsule. The upper ureter was dilated with an ectopic orifice or ureterocele. The third was the hydronephrosis type （12/83）. The severe hydronephrotic upper moiety was almost as big as the lower moiety. The upper ureter was severely dilated and circuitous with an ectopic orifice. The forth was the dual-poor type （2/83）. The two moieties were all very small with ＂Y＂ shaped ureters and ectopic orifices. The last was the dual-well type （20/83）. The upper moiety was almost the same size as the lower one, without apparent dilation of ＂Y＂ shaped or double ureters. Conclusion Based on kidney morphology, duplex kidney can be mainly classified into five types which can be depicted by CT urography prior to management and can provide an aid in selecting a successful course of surgical correction.