The value of color doppler ultrasonography combined with computed tomography angiography and magnetic resonance angiography in the preoperative quantification and classification of carotid body tumors: a retrospective analysis.

BACKGROUND: Computed tomography angiography (CTA) and magnetic resonance angiography (MRA) provide accurate vascular imaging information, but their use may be contraindicated. Color Doppler ultrasonography (CDU) provides simple, safe, noninvasive, and reproducible imaging. We therefore investigated the role of preoperative CDU combined with CTA and MRA in the quantification, typing, and diagnosis of carotid body tumors (CBTs). METHODS: We retrospectively analyzed patients with CBTs categorized into group A (type I [n = 1] and type II [n = 10]) or group B (type III [n = 56]) per the intraoperative Shamblin classification. CDU, CTA, and MRA characteristics of CBTs were observed, surgical results were correlated, and the diagnostic threshold of the CBT classification was calculated. RESULTS: CBTs were usually located at the common carotid artery bifurcation, encircling the carotid artery. An increased angle was found between the internal and external carotid arteries. On CDU, CBTs primarily presented as homogeneous hypoechoic masses with clear boundaries, rich flow signals, and a high-speed, low-resistance artery-like flow spectrum. CTA showed uniform or heterogeneous marked enhancement. MRA showed mixed T1 and slightly longer T2 signals and uniform or uneven obvious enhancement. With increases in the lesion size, amount of blood transfused, and operation time, the intraoperative classification level and possibility of skull-base invasion increased. When the maximum diameter of the lesion, the volume of the tumor, the distance between the upper margin of the tumor to the mastoid and the mandibular angle were 3.10 cm, 10.15 cm3, - 3.26 cm, and 0.57 cm, respectively, the largest Youden index was the best diagnostic boundary value for Shamblin type III tumors. CONCLUSIONS: CDU combined with CTA and MRA can accurately evaluate the size and classification of CBTs.

Elastic Net based sparse feature learning and classification for Alzheimer's disease identification.

Magnetic resonance imaging (MRI) has been successfully applied to investigate neuron pathological changes. Since the high dimension of observation data, sparse feature learning plays an important role in overcoming the challenge of high variable dimension and low sample size problem among the disease identification. In this paper, sparse Elastic Net (EN) was used to extract low dimension features and to identify the Alzheimer's disease (AD). Compare with principal component analysis (PCA) method, the EN method can solve the problems of less samples and high correlations between variables. For those variables sharing the same biological phenomenon, it selected whole groups into the model automatically once one variable among them was selected. Unlike other subspace learning methods, the proposed method used less man-made feature setting. The problems of dimension reduction and classification were conducted into a similar formulation. Experimental results illustrated the effectiveness of the proposed method.

Compartmental sparse feature selection method for Alzheimer's disease identification.

For high-dimensional magnetic resonance imaging (MRI) data, many feature selection methods have been proposed to reduce feature dimension in the study of computer-aided Alzheimer's disease (AD) diagnosis. This paper presents a compartmental sparse feature selection method used for AD identification. Based on the derived atlas-based regions-of-interest (ROIs) of brain, the proposed method partitioned the T1-weighted MRI data into several compartments. It performs feature selection and classification compartmentally according to the local feature dimension estimation and local feature selection using sparse principal component analysis (SPCA) method followed with elastic-net logistic regression (ENLR) classifier. Experimental results showed that the proposed method improves the classification performance for small ROIs with high computational efficiency.

Characteristics of Cerebral Blood Flow and Cerebral Gray Matter in Patients with Mild Alzheimer's Disease Using Voxel-based Method / 中国医学影像学杂志

Purpose Early diagnosis of Alzheimer's disease is lack of objective imaging marker.This study evaluates characteristics of cerebral blood flow (CBF) and gray matter atrophy in patients with mild Alzheimer's disease (AD) by using 3D arterial spin labeling (3D ASL) and thin slice 3D T1 weighted images of voxel-based method (VBM).Materials and Methods Sixteen mild AD patients (mild AD group) and sixteen normal control subjects (control group) were recruited.3D ASL and T1WI SPGR sequences were performed.By using voxel-based method,the whole brain CBF and T1WI images were analyzed.CBF and volume of gray matter were compared between two groups,and correlation analysis was done.Results Compared with control group,CBF hypoperfusion was detected in bilateral precuneus,cunei,middle temporal cortex,superior temporalcortex,left parahippocampal gyrus,left superior temporal pole and right superioroccipital gyrus in mild AD group (t=3.84,Pcorrected＜0.05).Compared with control group,gray matter atrophy was found in bilateral hippocampi,amygdalae,superior temporal pole,left parahippocampal gyrus,left inferior temporal cortex in mild AD group (t=4.12,Pcorrected＜0.05).There was a correlation in left parahippocampal gyrus and left upper pole of the temporal between changes of CBF and volume of gray matter in mild AD patients (r=0.50,P＜0.05).Conclusion Voxel-based VBM and ASL can evaluate AD patients' cerebral atrophy and CBF change in early stage,and there is a correlation between changes of CBF and gray matter atrophy in some overlap areas.

Prognostic value of coronary artery calcium score in patients with stable an-gina pectoris after percutaneous coronary intervention / 老年心脏病学杂志（英文版）

Objectives To evaluate the prognostic value of the coronary artery calcium (CAC) score in patients with stable angina pectoris (SAP) who underwent percutaneous coronary intervention (PCI). Methods A total of 334 consecutive patients with SAP who underwent first PCI following multi-slice computer tomography (MSCT) were enrolled from our institution between January 2007 and June 2012. The CAC score was calculated according to the standard Agatston calcium scoring algorithm. Complex PCI was defined as use of high pressure bal-loon, kissing balloon and/or rotablator. Procedure-related complications included dissection, occlusion, perforation, no/slow flow and emer-gency coronary artery bypass grafting. Main adverse cardiac events (MACE) were defined as a combined end point of death, non-fatal myo-cardial infarction, target lesion revascularization and rehospitalization for cardiac ischemic events. Results Patients with a CAC score>300 (n=145) had significantly higher PCI complexity (13.1%vs. 5.8%, P=0.017) and rate of procedure-related complications (17.2%vs. 7.4%, P=0.005) than patients with a CAC score≤300 (n=189). After a median follow-up of 22.5 months (4-72 months), patients with a CAC score≤300 differ greatly than those patients with CAC score>300 in cumulative non-events survival rates (88.9 vs. 79.0%, Log rank 4.577, P=0.032). After adjusted for other factors, the risk of MACE was significantly higher [hazard ratio (HR):4.3, 95%confidence inter-val (95%CI):2.4-8.2, P=0.038] in patients with a CAC score>300 compared to patients with a lower CAC score. Conclusions The CAC score is an independent predictor for MACE in SAP patients who underwent PCI and indicates complexity of PCI and proce-dure-related complications.

Diffusion tensor imaging study of hind-limb ischemia model on rabbit / 中华放射学杂志

Objective To explore the application of diffusion tensor imaging in the assessment of ischemic muscle in hind-limb ischemia model of rabbit. Methods Excision of femoral artery in unilateral hind limb was done in 14 New Zealand white rabbits and ischemic model were established in 12 rabbits. Three (12 rabbits),10(10 rabbits) ,28(7 rabbits),56(5 rabbits) days after the model establishment, DTI scan was performed on bilateral hind limbs in each of the models, respectively and, λ_1,λ_2,λ_3, ADC and FA values were measured. Histological analysis was also performed at these time points. Pared t test was used to compare the differences of these indexes in bilateral hind limbs. Results Following femoral artery excision, a rapid ascending of ADC,λ_2,λ_3 values with sharply reduced FA value was observed in ligated hind-limb, which reached maximal on 3 days post-excision (ADC_(ligated)= 1.72±0.16, ADC_(unligated)= 1.53±0.16, t = 6.48, P < 0.01 ; λ_(2 ligated)= 1.70±0.15, λ_(2 unligated)= 1.51±0.06, t=10.87, P < 0.01 ; λ_(3 ligated_ =1.17±0.12, λ_(3 unligated)= 0.88±0.12, t=6.67, P < 0.01 ; FA_(ligated)= 0.24±0.04, FA_(unligated) =0.39±0.03, t = -10.61 ,P <0.01) and histologic analysis revealed the severest muscle damag at that time. Ischemic muscle recovered very slowly during the first 10 day post-excision accompanied with reduction of ADC , λ_2, λ_3 values, however there was also difference of ADC,λ_2, λ_3 values between ligated and nonligated limbs except λ_1 ( ADC_(ligated) = 1.65±0. 16, ADC_(unligated)= 1.50±0.12, t =6.42, P <0.01 ; λ_(2 ligated) = 1.62±0.32, λ_(2 unligated) =1.48±0.31, t=5.09, P < 0.01) ; λ_(3 ligated)= 1.11±0.13, λ_(3 unligated)= 0.85±0.09, t=6.26, P <0. 01;λ_(1 ligated)=2.20±0.21, λ_(1 unligated) =2.18+0.20, t=0.87, P=0.40). After 28 days, ADC and λ_3 returned to normal (ADC_(ligated)= 1.51±0. 16, ADC_(unligated)= 1.55±0.14, t=-1.35, P=0.23 ; λ_(3 ligated) =0.95±0. 10, λ_(3 unligated)= 0.92±0.06, t=1.70, P=0.14), but λ_2 and FA of ligated limb were still different from those of nonligated limb (λ_(2 ligated)= 1.45±0.23, λ_(2 unligated)= 1.52±0. 95, t=-3.56, P=0.012; FA_(ligated)=0.35±0.02, FA_(unligated)=0.40±0.03, t=-3.83, P<0.01). After 56 days, all parameters retuned to normal(ADC_(ligated) =1.57±0.18, ADC_(unligated)=1.58±0.23, t=-0.71, P=0.52; λ_(1 ligated) =2.18±0.18, λ_(1 unligated)=2.24±0.14, t=-0.22, P=0.10; λ_(2 ligated)=1.64±0.13, λ_(2 unligated)=1.59±0.15, t=0.89, P=0.42; λ_(3 ligated)=0.89±0.1,λ_(3 unligated)=0.91±0.07, t=- 1.64,P= 0.18; FA_(ligated)= 0.39±0. 03, FA_(unligated)= 0.41±0.02, t=-0.83, P=0.47). Conclusion DTI is a quantitative and relatively accurate technique to assess time-dependent changes of ischemic muscle in hindlimb ischemia model of rabbit.

Relation between enlarged volume of medial wall and degree of enophthalmos after orbital fracture / 中华医学美学美容杂志

Objective To explore the relation between the enlargement of orbital volume and the degree of enophthalmos, and that between the enlarged volume of floor together with that of medial wall and the degree of enophthalmos. Methods A total of 17 patients of unilarteral orbital fracture were scanned by MSCT (slice width 0.625mm), who suffered late enophthalmos as a results of combination fracture of the medial wall and floor. The clinical data were collected, and input into a software named MIMICS in order to measure orbital volume, the degree of enophthalmos, the enlarged volume of medial wall, and that of orbital floor. Simple linear correlation and regression were carried out between the enlargement of orbital volume and the degree of enophthalmos. Mutiple linear correlation and regression were carried out between the enlarging volume of floor together with that of medial wall and the degree of enophthalmos. Results The equation of the enlargement of orbital volume (V) and the degree of enophthalmos (E) was E= 0.851 V-0.197 (Pearson r=0.969, P＜0.01, the 95% confidence intervals of 0.732-0.970). The standardized equation between the enlarged volume of floor together with that of medial wall and the degree of enophthalmos was E= 0.690 VF+0.413 VM-0. 086 (setpwise, entry =0.5, removal= 0. 11,P＜0.01 ); Comparing the standardized coefficients of independent variables, the outcome was bF (0.690) ＞ bM(0.413). Conclusion Significant linear correlation between the increment of the orbital volume and the degree of enophthalmos is found that 1.0 ml enlargeement in bony volume causes approximately 0.9 mm of enophthalmos; enlarged volume of floor has more powerful influence on the degree of enophthalmos than enlarged volume of medial wall, the former is 1.56 times of the latter.

Application of functional magnetic resonance imaging(fMRI) in the study of visceral hypersensitivity of the gut / 北京大学学报(医学版)

Functional magnetic resonance imaging(fMRI) has been widely applied in many fields,such as neurology,psychology,etc.Recently it has also been used to study the visceral hypersensitivity of the gut.This review gives an overview of the basic principle of fMRI and its application in the visceral sensitivity of esophagus and rectum.