Regional blood flow analysis and its relationship with arterial branch lengths and lumen volume in the coronary arterial tree

The limitations of visually assessing coronary artery disease are well known. These limitations are particularly important in intermediate coronary lesions (30-70% diameter stenosis) where it is difficult to determine whether a particular lesion is the cause of ischaemia. Therefore, a functional measure of stenosis severity is needed. The purpose of this study is to determine whether the expected maximum coronary blood flow in an arterial tree is predictable from its sum of arterial branch lengths or lumen volume. Using a computer model of a porcine coronary artery tree, an analysis of blood flow distribution was conducted through a network of millions of vessels that included the entire coronary artery tree down to the first capillary branch. The flow simulation results show that there is a linear relationship between coronary blood flow and the sum of its arterial branch lengths. This relationship holds over the entire arterial tree. The flow simulation results also indicate that there is a 3/4 power relation between coronary blood flow (Q) and the sum of its arterial lumen volume (V). Moreover, there is a linear relationship between normalized Q and normalized V raised to a power of 3/4 over the entire arterial tree. These results indicate that measured arterial branch lengths or lumen volumes can be used to predict the expected maximum blood flow in an arterial tree. This theoretical maximum blood flow, in conjunction with an angiographically measured blood flow, can potentially be used to calculate fractional flow reserve based entirely on angiographic data.     

The role of MSCT angiography in early detection of lower limb arterial lesions in patients with antiphospholipid syndrome

Antiphospholipid syndrome (APS) is an autoimmune disease which is characterized by arterial and venous thromboses, fetal loss, and the presence of antiphospholipid antibodies in the serum. It is characterized by accelerated atherosclerosis. Increased tendency towards thrombosis leads to the occurrence of various vascular events. The objective of our study was to determine if there are subclinical changes on lower limb arteries in APS patients and what the best diagnostic choice for their establishment is. In this study, we analyzed 50 patients with primary antiphospholipid syndrome (PAPS) and 50 patients, who have secondary antiphospholipid syndrome (SAPS). The results were compared to 50 controls. The groups were comparable with respect to age, gender, and traditional risk factors except for the lipid status, since controls had significantly higher levels of cholesterol and triglycerides. Study was conducted on 64-multi-slice computed tomography (64-MSCT), where we analyzed quantitative and morphological characteristics of blood vessel-detected lesions. Patients from the control group had statistically very significant elevated cholesterol and triglyceride levels in regard to the patients with SAPS and PAPS (p < 0.001 and p < 0.05). Analyzing percentage of diameter stenosis, we have established that lesions from group with 0–30% diameter stenosis (DS) in patients with PAPS (n = 47) and SAPS (n = 39) are more common than that in control group (n = 3, p < 0.001). The incidence of lesions higher than 70% DS in control group (n = 74) was statistically significant than that in patients with SAPS (n = 74, p < 0.05), while very statistically significant than that in patients with PAPS (n = 48, p < 0.001). Analyzing the qualitative characteristics of plaques, we have established significant higher frequency of soft tissue (n = 32) and mixed lesions (n = 36) in patients with PAPS than the calcified one (n = 7, p < 0.001). Our study showed that the subclinical manifestation of changes on lower extremity arteries is more common in patients with APS. Because of its safety and accuracy, the method of choice is 64-MSCT angiography in monitoring disease progression.     

Removal of arterial wall calcifications in CT angiography by local subtraction

CT Angiography (CTA) is an established technique for the minimally invasive imaging of arteries. The technique of maximum intensity projection (MIP) is often used to get a comprehensive overview of the vascular anatomy. On a MIP, however, arterial wall calcifications may hinder the visualization of the arterial lumen. These calcifications are in direct contact with the contrast-enhanced blood, which makes removal difficult. We present a local subtraction method for the automatic removal of these calcifications. In our approach a second CT scan has to be made, prior to contrast injection. The calcifications in both scans are registered prior to subtraction to compensate for displacements in between the two scans. Local subtraction results are compared with results obtained by thresholding. The method was tested in a phantom and with data from four patients. The phantom represented an artery with different types of stenosis. Data were used from patients for which CTA of the renal arteries was performed. For two patients the electrocardiogram (ECG) was recorded during the CTA examination, making retrospective cardiac gated reconstructions possible. Both the phantom and the patient study showed that the local subtraction method is capable of removing calcifications and visualizing the residual lumen. In the patient study it appeared that some artifacts remained for higher pitch values. We conclude that the local subtraction method is less subjective and more accurate than thresholding. Best results are obtained by use of a small pitch, at the expense of the volume covered during a single breath hold.     

自体外周血干细胞移植促进患者下肢动脉缺血性溃疡愈合

目的探讨应用自体外周血干细胞移植技术治疗患者下肢动脉缺血性溃疡和静息痛可行性及存在的问题。方法自2004年3月—2007年2月,16例下肢动脉缺血性溃疡及静息痛患者通过采用重组人粒细胞集落刺激因子(G-CSF)动员骨髓干细胞增殖并释放入血,在第5~6天应用血细胞分离机进行外周血干细胞的采集,并将采集到的浓集干细胞液作患肢小腿肌肉注射。结果16例患者经干细胞移植治疗后间歇性跛行时间及距离均延长,其中,12例患者静息痛均缓解;11例溃疡愈合。病人均随访3~24个月。4例失访。结论应用自体外周血干细胞移植技术治疗下肢动脉缺血性溃疡和静息痛是一种可行且有效的方法。     

经皮腔内血管成形术治疗糖尿病下肢动脉血管病变的临床疗效观察

目的探讨介入治疗经皮腔内血管成形术(PTA)治疗糖尿病下肢动脉血管病变的临床疗效,为糖尿病下肢动脉病变选择最佳治疗方案提供参考。方法将60例患者平均分为对照组和介入组,对照组采取传统药物治疗,介入组采取经皮腔内血管成形术(PTA)治疗。观察比较2组术后12周、24周踝肱指数(ABI)、足背动脉平均血流速度、搏动指数(PI)、无痛最大行走距离的变化情况。结果介入组在术后12周和24周的踝肱指数(ABI)、足背动脉平均血流速度、搏动指数(PI)、无痛最大行走距离均较对照组有所提高,2组间比较差异具有统计学意义(P0.05);分别与本组治疗前比较,差异具有统计学意义(P0.05);但组内24周与12周比较,各项指标变化均无统计学差异(P0.05)。结论经皮腔内血管成形术(PTA)治疗糖尿病下肢动脉病变优于传统药物治疗,是临床可行的糖尿病下肢动脉病变的治疗方式。     

Atlas of the muscle motor points for the lower limb: implications for electrical stimulation procedures and electrode positioning

The aim of the study was to investigate the uniformity of the muscle motor point location for lower limb muscles in healthy subjects. Fifty-three subjects of both genders (age range: 18–50 years) were recruited. The muscle motor points were identified for the following ten muscles of the lower limb (dominant side): vastus medialis, rectus femoris, and vastus lateralis of the quadriceps femoris, biceps femoris, semitendinosus, and semimembranosus of the hamstring muscles, tibialis anterior, peroneus longus, lateral and medial gastrocnemius. The muscle motor point was identified by scanning the skin surface with a stimulation pen electrode and corresponded to the location of the skin area above the muscle in which an electrical pulse evoked a muscle twitch with the least injected current. For each investigated muscle, 0.15 ms square pulses were delivered through the pen electrode at low current amplitude (<10 mA) and frequency (2 Hz). 16 motor points were identified in the 10 investigated muscles of almost all subjects: 3 motor points for the vastus lateralis, 2 motor points for rectus femoris, vastus medialis, biceps femoris, and tibialis anterior, 1 motor point for the remaining muscles. An important inter-individual variability was observed for the position of the following 4 out of 16 motor points: vastus lateralis (proximal), biceps femoris (short head), semimembranosus, and medial gastrocnemius. Possible implications for electrical stimulation procedures and electrode positioning different from those commonly applied for thigh and leg muscles are discussed.     

短跑运动中下肢环节间互动动力学分析

目的从动作控制角度出发,探讨运动控制对提高短跑运动成绩以及预防运动损伤的可能影响。方法研究对象为8名国家级优秀短跑运动员(最好成绩:10.27s～10.80s),利用8台红外高速摄像系统(采样频率300Hz)与测力台系统(1200Hz)同步记录受试者在短跑最大速度阶段的运动学与动力学地面反作用力资料。根据逆动力学理论建立下肢多环节互动动力学模型,对短跑一个步幅的各种力矩进行量化分析。结果短跑支撑阶段地面反作用力矩是下肢各关节处的主要被动力矩,它在着地初期对膝关节产生一个较大的伸膝作用,腿后肌为抵抗此力矩的     

Doppler flow velocity in assessment of peripheral arterial disease in the lower limbs

In 74 patients with the chronic obliterative arterial disease of the lower limbs, the systolic perfusion pressure and the ankle systolic pressure index were measured using CW-Doppler ultrasound on the dorsalis pedis and posterior tibial arteries. At the same time Doppler flow velocity recordings were made at the femoral, popliteal and pedal levels. Peak foreward velocity and peak reverse velocity were measured directly from the tracing, while blood acceleration and deceleration as well as the acceleration/deceleration index were calculated using simple arithmetics. Patients with obliterative arterial disease had a significantly lower systolic pressure and ankle systolic pressure index in both pedal arteries than healthy volunteers constituting the control group. Peak forward velocity, acceleration and deceleration had a great accuracy in evaluating the peripheral circulatory status in affected persons, while peak reverse velocity and the acceleration/deceleration index were reproducible only at the high femoral level. Doppler velocity tracings appeared to be as useful in evaluating the peripheral arterial circulation as the previously used systolic perfusion pressure and ankle systolic pressure index.     

Endothelial dysfunction in obstructive sleep apnea measured by peripheral arterial tone response in the finger to reactive hyperemia

STUDY OBJECTIVE: The aim of this study was to investigate endothelial functioning in sleep apnea patients using a novel plethysmographic device that monitors peripheral arterial tone response in the finger to reactive hyperemia induced by forearm ischemia. PARTICIPANTS: Forty-six sleep apnea patients, 74.0% men, mean age 46.8 +/- 9.3 years, and 17 control subjects without sleep apnea, 64.7% men, mean age 47.1 +/- 6.7 years. SETTING: Eight-bed Technion Sleep Medicine Center in Haifa, Israel. DESIGN: Endothelial functioning assessed by the reactive hyperemia peripheral arterial tone index was measured twice, before sleep and after waking from sleep monitored by polysomnography in the laboratory. The reactive hyperemia peripheral arterial tone index was calculated as the average amplitude of the peripheral arterial tone signal after the cuff deflation divided by the average amplitude before the cuff inflation. RESULTS: Morning index of endothelial functioning was significantly lower in patients with moderate to severe sleep apnea (apnea-hypopnea index > or = 30) than in patients with mild sleep apnea (30 < apnea-hypopnea index < or = 10) and in the control group without sleep apnea (apnea-hypopnea index < 10). The morning index was significantly inversely correlated with apnea-hypopnea index. Patients with a history of hypertension or cardiovascular disease had significantly lower morning and evening indexes of endothelial functioning than patients without such a history. Multivariate analysis revealed that apnea-hypopnea index and sleep efficiency were significant predictors of the morning index. CONCLUSION: Measurements of the response of the peripheral arterial tone in the finger to reactive hyperemia can be used as a substitute for the brachial artery ultrasound technique to measure endothelial functioning in patients with sleep apnea.     

Dimensions of central venous structures in humans measured in vivo using magnetic resonance imaging: implications for central-vein catheter dimensions

The tip of a central vein catheter for hemodialysis should be located in the upper right atrium for the best performance. Hemodialysis catheters do have internal diameters unadjusted to the catheter length; however, the longer the catheter the slower the flow at the same pressure difference. On the other hand, the catheter diameter cannot be so large as to fill the vein too tightly as it predisposes to damage of the vein wall, thrombosis and stenosis. Therefore, the catheter length and diameter should be appropriate for the patient. For this purpose, the exact dimensions of the venous system in vivo should be known. In this study we correlated the anthropometric measurements and the dimensions of the large upper body veins in 31 adult volunteers. After deep inspiration, magnetic resonance imaging of the chest was performed in three planes; the positions of specific points in the three-dimensional coordinate system were measured, and the distance to adjacent points was calculated according to the analytic geometry formula. The total length from the catheter entry point to the right atrium was the sum of distances between the adjacent points. The lengths of the veins were correlated with the body anthropometric measurements (height, weight, body surface area, bi-acromion span, and height plus bi-acromion span). The best overall correlations of the lengths and diameters of the large upper body veins are with the body surface area. A table is included to guide the selection of the total catheter length and diameter in relation to the body surface area and insertion site.     

自体骨髓单个核细胞移植治疗糖尿病下肢周围神经病变

背景：有研究表明移植骨髓单个核细胞治疗糖尿病下肢神经病变动物模型,通过在组织内能促进血管再生和增加血管生成因子及神经营养因子能改善临床症状。                             目的：观察自体骨髓单个核细胞移植治疗糖尿病下肢周围神经病变的临床效果。 方法：30例糖尿病下肢闭塞症患者60条下肢,按治疗方式的不同分为2组：自体骨髓单个核细胞移植的治疗组和对侧下肢非自体骨髓单个核细胞移植的对照组,各30条下肢。 结果与结论：移植4周后,治疗组总有效率高于对照组(P < 0.05)。两组治疗后神经病变自主症状问卷神经病变主觉症状问卷评分均较治疗前明显降低,治疗组评分降低更明显(P < 0.01),治疗组胫神经和腓总神经感觉和运动神经传导速度均较对照组快(P < 0.01),患者未出现并发症和不良反应。说明自体骨髓单个核细胞移植治疗糖尿病下肢周围神经病变的临床效果较好。     

Validity of the transfer function model of the human arterial system of the lower limb in man

A transfer function model of the human arterial system has been examined and tested on a group of 21 patients undergoing reconstructive arterial surgery in the leg. It was found that use of the model to estimate parameters relating to proximal (above femoral artery) arterial wall stiffness and radius is not reliable, the model being affected by the peripheral resistance. The value of the model parameters relating to the peripheral arterial radius is more consistent with the theory although there are still contradictions. It is concluded that the application of transfer function modelling to the diagnosis of arterial disease should be approached with caution.     

阻塞性睡眠呼吸暂停低通气患者舌动脉CT成像测量及其意义

目的探讨阻塞性睡眠呼吸暂停低通气综合征(OSAHS)患者间舌动脉CT血管成像(CTA)特点,为临床中线舌部分切除手术提供参考。方法对93例OSAHS患者进行舌咽区上呼吸道CT扫描和舌动脉CTA成像测量,比较不同舌腭关系分型的OSAHS患者组各项测量参数的差异。结果 4组不同舌腭关系分型的OSAHS患者间年龄、AHI、LSaO2和舌宽无明显差别,但BMI、舌后区呼吸道截面积、舌宽、舌长和舌厚度存在明显差别。4组间舌动脉长度(mm)分别为93.6±15.84、95.9±16.39、99.6±15.19、110.0±12.16;舌盲孔区舌动脉深度(mm)分别为27.4±5.81、27.3±4.28、28.0±4.43、31.2±6.38;舌动脉间距(mm)分别为21.7±3.57、23.1±4.90、22.8±5.53、25.6±4.60,组间差异均显著。舌动脉深度和间距分别与舌厚和舌宽显著相关。结论不同舌腭关系分型的OSAHS患者间舌动脉走行和测量参数存在明显差别,差别的原因与舌体肥厚等解剖改变有关。     

The lengths of the fibres of Henle in the retina of macaque monkeys: implications for vision

In Golgi preparations of retinae from macaque monkeys the lengths of the fibres of Henle from photoreceptors, and Müller's fibres were measured. It was shown that the lengths of Müller's fibres provide a good estimate of the lengths of adjacent fibres of Henle of photoreceptors. The fibres form a radiate pattern with respect to the fovea. They are longest at the fovea and their length decreases in a systematic way with distance from the fovea. The implications of the fibre length are considered with respect to the relationship between the ganglion cell distribution and central magnification factors. We show that even when the functional offset introduced by the fibres of Henle and by bipolar and ganglion cells is taken into account there is not a constant proportional relationship between ganglion cells and central magnification factors. The representation of the central few degrees of the visual field on the striate cortex is greater than would be predicted on the basis of the ganglion cell density for the central retina.     

Intimal fibrosis (phlebosclerosis) in the saphenous vein of the lower limb: A quantitative analysis

Summary The influence of pre-existing phlebosclerosis on the patency rate of aorto-coronary bypasses is uncertain. To examine this influence, extensive quantitative histological investigations of the intimal thickness of the left saphenous vein were made in 30 cases. In almost all veins the intima was thickened by collagen and elastic fibres as well as by fusiform cells which were assumed to be smooth muscle cells. The innermost layers also contained increased collagen adding to the intimal thickening. Three different methods to measure the intimal thickness were tested morphometrically: planimetric, a four-point method and a so-called method of estimate. The latter is the most time-saving and effective method. The average intimal thickness showed considerable deviations, but the intimal thickness in individual veins did not deviate greatly. As a rule, a specimen with an intimal thickness of less than 100 m belonged to a vein with mild or moderate intimal thickening, but specimens with an average intimal thickness of 100–250 m usually derived from a vein with moderate or pronounced intimal fibrosis. However, extreme values allowed a more precise statement to be made. A specimen with a non-sclerotic intima suggested at best a mild intimal fibrosis of the vein in the lower limb, whereas a specimen with marked intimal thickening derived from a vein with severe phlebosclerosis.     

测量并分析上楼梯过程中下肢关节角变化

目的获取上楼梯运动过程中国人下肢关节活动范围的统计学数据,从而为大屈曲度人工关节设计提供依据。方法设计常规楼梯实验装置,利用运动捕捉系统(Optotrak Certus,NDI)和三维测力台(AMTI,Bertec),建立系统地测量上楼梯过程中下肢运动的方法,并应用此方法对40例样本进行测量。结果计算获得了40例样本在上楼梯过程中,髋关节、膝关节及踝关节在1个运动周期内沿各方向上关节角的变化规律及活动范围,其中髋、膝、踝关节在矢状面上活动范围分别是-1.6°～66.7°,0°～91.4°,-20.8°～22.4°。结论上楼梯运动过程中,髋、膝、踝关节在矢状面上活动度最大,且髋关节和膝关节屈曲度最大。与水平路面上正常行走和慢跑运动中关节运动范围比较,上楼梯运动中,髋关节和膝关节在矢状面上运动范围均较大。     

Anatomical study to the vessels of the lower limb by using CT scan and 3D reconstructions of the injected material

Purpose  

To find out the advantages and insufficiency of the 3D reconstruction and traditional anatomy by comparing them with each other.     

Prevalence of frailty in patients with lower extremity peripheral arterial disease: A systematic review and meta-analysis

BackgroundIncreasing studies have reported on the prevalence of frailty in patients with peripheral artery disease (PAD). The aim of this systematic review and meta-analysis was to estimate the pooled prevalence of frailty in patients with lower extremity PAD.MethodsTwo authors systematically searched PubMed and Embase databases from their inception to August 8, 2022. Original articles that reported the prevalence of frailty in patients with lower extremity PAD were included. The prevalence of frailty in patients with lower extremity PAD was pooled using a random-effect model. Meta-regression, subgroup, and sensitivity analyses were conducted to explore the heterogeneity.ResultsEighteen studies reported on 17 articles involving 1,726,343 patients with lower extremity PAD were identified. The pooled prevalence of frailty in patients with lower extremity PAD was 49 % (95 % confidence interval [CI] 37–61 %), with significant heterogeneity between studies (I ² = 100 %, p < 0.001). Multivariable meta-regression showed that only the severity of PAD (coefficient 0.270; 95 % CI 0.017–0.523, p = 0.039) was significantly associated with the heterogeneity. In subgroup analysis, the pooled prevalence of frailty was higher in critical limb ischemia or chronic limb-threatening ischemia (54 %) than all PAD (48 %); the pooled prevalence of frailty was 64 %, 51 %, and 54 % for Modified Frailty Index-5, Modified Frailty Index-11, and Clinical Frailty Scale, respectively. The pooled prevalence of frailty appeared to be lower in male (39 %) than the female patients (47 %).ConclusionsThe prevalence of frailty was higher in patients with lower extremity PAD, suggesting frailty is a common condition. This finding highlights the significance of assessing frailty in patients with lower extremity PAD.