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101.
In situ hemodynamics of perforating veins in chronic venous insufficiency   总被引:2,自引:0,他引:2  
PURPOSE: The prevalence of incompetent perforators increases linearly with the clinical severity of chronic venous insufficiency (CVI) and the presence of deep vein incompetence. Putative transmission of deep vein pressure to skin may cause dermal hypoxia and ulceration. Despite extensive prospective interest in the contribution of perforators toward CVI, their hemodynamic role remains controversial. The aim of this prospective study was to determine the in situ hemodynamic performance of incompetent perforating veins across the clinical spectrum of CVI, by means of duplex ultrasonography. METHODS: A total of 265 perforating veins of 90 legs that had clinical signs and symptoms consistent with CVI in 67 patients referred consecutively to the blood flow laboratory were studied. The clinical distribution of the examined limbs was CEAP(0), 10 limbs; CEAP(1-2), 39 limbs; CEAP(3-4), 21 limbs; and CEAP(5-6), 20 limbs. With the use of gated-Doppler ultrasonography on real-time B-mode imaging, the flow velocity waveforms were obtained from the lumen of perforators on release of manual distal leg compression in the sitting position and analyzed for peak and mean velocities, time to peak velocity, volume flow, venous volume displaced outward, and flow pulsatility. The diameter and duration of outward flow (abnormal reflux > 0.5 seconds) were also measured. RESULTS: Incompetent perforators had bigger diameters, higher peak and mean velocities and volume flow, longer time to peak velocity, and bigger venous volume displaced outward (VV(outward)) than competent perforators (all, P <.0001). The diameter of incompetent perforators did not change significantly with CEAP class (all, P >.1). Incompetent thigh and lower-third calf perforators had a significantly bigger diameter than perforators in the upper and middle calf combined (both, P <.05), in incompetent perforators: reflux duration was unaffected by CEAP class or site (P >.3); peak velocity was higher in those in CEAP(3-4) than those in CEAP(1-2) (P =.024); mean velocity in those in CEAP(3-6) during the first second of reflux was twice that of those in CEAP(1-2) (P <.0001); both higher volume flow and VV(outward) were found in the thigh perforators than those in the upper and middle calf thirds (P <.03); CEAP(3-6) volume flow and VV(outward), both in the first second, were twice that in those in CEAP(1-2) (P <.002); flow pulsatility in those in CEAP(5-6) was lower than in those in CEAP(1-2) (P =.014); in deep vein incompetence, higher peak velocity, volume flow, VV(outward), and diameter occurred than in its absence (P <.01). CEAP designation correlated significantly with mean velocity and flow pulsatility, both in the first second (r = 0.3, P <.01). The flow direction pattern in perforator incompetence was uniform across the CVI spectrum: inward on distal manual limb compression, and outward on its release; competent perforators had a smaller percentage of outward flow on limb compression (P <.01). CONCLUSION: In addition to an increase in diameter, perforator incompetence is characterized by significantly higher mean and peak flow velocities, volume flow, and venous volume displaced outward, and a lower flow pulsatility. Differences in early reflux enable a better hemodynamic stratification of incompetent perforators in CVI classes. In the presence of deep reflux, incompetent perforators sustain further hemodynamic impairment. In situ hemodynamics enable quantification of the function of perforators and can be used in the identification of the clinically relevant perforators and the impact of surgery.  相似文献   
102.
The Delis-Kaplan Executive Function System (D-KEFS) Trail Making Test (TMT), a modification of the original TMT, was created to isolate set-shifting (Letter-Number Switching) from other component skills. This was accomplished by including four baseline conditions (Visual Scanning, Number Sequencing, Letter Sequencing, and Motor Speed) and by placing equal numbers of stimuli in the three sequencing conditions. Given that some studies with the original TMT demonstrated a significant effect of education and intellectual functioning on performance, we utilized the D-KEFS national standardization sample to examine the effects of education and vocabulary level-i.e., Vocabulary subtest from the Wechsler Abbreviated Scale of Intelligence (WASI)-on the D-KEFS TMT. The results indicate a significant effect of these variables on each D-KEFS TMT condition. Normative tables for education- and vocabulary-adjusted scaled scores based on the database from the D-KEFS national normative study were generated.  相似文献   
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Magnification mammography is a special technique used in the cases where breast complaints are noted by a woman or when an abnormality is found in a screening mammogram. The carcinogenic risk in mammography is related to the dose deposited in the glandular tissue of the breast rather than the adipose, and average glandular dose (AGD) is the quantity taken into consideration during a mammographic examination. Direct measurement of the AGD is not feasible during clinical practice and thus, the incident air KERMA on the breast surface is used to estimate the glandular dose, with the help of proper conversion factors. Additional conversion factors adapted for magnification and tube voltage are calculated, using Monte Carlo simulation. The effect of magnification degree, tube voltage, various anode/filter material combinations and glandularity on AGD is also studied, considering partial breast irradiation. Results demonstrate that the estimation of AGD utilizing conversion factors depends on these parameters, while the omission of correction factors for magnification and tube voltage can lead to significant underestimation or overestimation of AGD. AGD was found to increase with filter material's k-absorption edge, anode material's k-emission edge, tube voltage and magnification. Decrease of the glandularity of the breast leads to higher AGD due to the increased penetrating ability of the photon beam in thick breasts with low glandularity.  相似文献   
107.
BACKGROUNDChronic heart failure (CHF) is a complex syndrome characterized by a progressive reduction of the left ventricular (LV) contractility, low exercise tolerance, and increased mortality and morbidity. Diastolic dysfunction (DD) of the LV, is a keystone in the pathophysiology of CHF and plays a major role in the progression of most cardiac diseases. Also, it is well estimated that exercise training induces several beneficial effects on patients with CHF. AIMTo evaluate the impact of a cardiac rehabilitation program on the DD and LV ejection fraction (EF) in patients with CHF.METHODSThirty-two stable patients with CHF (age: 56 ± 10 years, EF: 32% ± 8%, 88% men) participated in an exercise rehabilitation program. They were randomly assigned to aerobic exercise (AER) or combined aerobic and strength training (COM), based on age and peak oxygen uptake, as stratified randomization criteria. Before and after the program, they underwent a symptom-limited maximal cardiopulmonary exercise testing (CPET) and serial echocardiography evaluation to evaluate peak oxygen uptake (VO2peak), peak workload (Wpeak), DD grade, right ventricular systolic pressure (RVSP), and EF.RESULTSThe whole cohort improved VO2peak, and Wpeak, as well as DD grade (P < 0.05). Overall, 9 patients (28.1%) improved DD grade, while 23 (71.9%) remained at the same DD grade; this was a significant difference, considering DD grade at baseline (P < 0.05). In addition, the whole cohort improved RVSP and EF (P < 0.05). Not any between-group differences were observed in the variables assessed (P > 0.05).CONCLUSIONExercise rehabilitation improves indices of diastolic and systolic dysfunction. Exercise protocol was not observed to affect outcomes. These results need to be further investigated in larger samples.  相似文献   
108.
Magnetic resonance imaging was utilized to determine the nature and rate of subcortical abnormalities in bipolar affective disorder. Nine of 19 bipolar patients and no controls demonstrated subcortical signal hyperintensities on blind evaluation of the images. There was no apparent change in the appearance of the hyperintensities in 7 of 7 subjects with abnormal magnetic resonance images who underwent repeated imaging at 1 year. Bipolar patients with abnormalities had a history of more hospitalizations and appeared more impaired on tests of fluency and recall when compared with bipolar patients without abnormalities or with controls. The possible etiology and significance of signal hyperintensities in bipolar affective disorder is discussed.  相似文献   
109.
For left-handers, cognitive functions are organized in the brain similarly to right-handers or they are more diffusely represented. In this study, we report a left-handed patient with a focal right temporal-parietal lesion who evidenced a lasting Wernicke's aphasia and visual-spatial functioning typical of a right-hander with left-hemisphere involvement. The patient's performance on other tasks (e.g. praxis, singing) as well as observed behavioral changes also resembled those of a right-hander with left-hemisphere compromise. This case suggests that it is possible for cognitive functions to be inversely represented in the two hemispheres.  相似文献   
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