Shear wave elastography of the ulnar nerve at the forearm

The study included 38 ulnar nerves in 20 healthy subjects. High-resolution ultrasound and Shear wave elastography were used to evaluate the ulnar nerve at the mid forearm. The mean cross-sectional area of the ulnar nerve was 7.1 mm². The mean shear elastic modulus of the nerve in the short axis was 27.4 kPa. The mean shear elastic modulus of the nerve in long axis was 24.7 kPa. No statistical relation could be noted between elasticity measurements in long and short axes. The ulnar nerve elastic modulus also showed no correlation with CSA neither in the long axis nor short axis. Age, height, weight, and body mass index showed no correlation with the ulnar elastic modulus in short or long axes. The elastic modulus of the ulnar nerve has been determined in healthy subjects and can serve as a reference for future assessment of compressive neuropathies of the ulnar nerve.     

Assessment of left atrial dimensions by cross sectional echocardiography in patients with mitral valve disease.

Left atrial dimensions were measured using cross sectional echocardiography in 37 patients with mitral valve disease and 30 normal subjects of similar ages. The anteroposterior (AP), superior-inferior (SI), and medial-lateral (ML) left atrial dimensions were determined at the end of ventricular systole using parasternal long and short axis and apical four chamber views (for SIa and MLa). To assess the reliability of these measurements cross sectional echocardiographic and angiographic left atrial volumes were compared in 19 patients with mitral valve disease, giving an excellent correlation. A moderate correlation was found between the anteroposterior dimension of the left atrium obtained using M mode echocardiography and that obtained using the parasternal short axis and long axis projections. In normal subjects a good correlation was found between SI and ML dimensions, while a lower correlation was found between SI and AP, and ML and AP dimensions. The SI dimension was the major axis of the left atrium and AP dimension the minor axis. In patients with mitral valve disease a good correlation was found between SI and ML dimensions, while SI and ML dimensions had a low correlation with AP dimensions. The AP dimension was the minor axis of the left atrium, while the SI and ML dimensions were not significantly different. All left atrial dimensions were significantly greater in patients with mitral valve disease than in normal subjects. Of 30 patients with at least one dimension increased, all three dimensions were abnormal in 16, two dimensions were increased in 10, and only one dimension was increased in four. AP, SI, and ML dimensions were abnormal in 25, 20, and 27 patients, respectively. Cross sectional echocardiography may provide a reliable estimate of left atrial dimensions. In patients with mitral valve disease a thorough examination of the left atrium using multiple cross sectional views is necessary to detect asymmetric left atrial enlargement and to measure the degree of left atrial dilatation.     

Assessment of left atrial dimensions by cross sectional echocardiography in patients with mitral valve disease

Left atrial dimensions were measured using cross sectional echocardiography in 37 patients with mitral valve disease and 30 normal subjects of similar ages. The anteroposterior (AP), superior-inferior (SI), and medial-lateral (ML) left atrial dimensions were determined at the end of ventricular systole using parasternal long and short axis and apical four chamber views (for SIa and MLa). To assess the reliability of these measurements cross sectional echocardiographic and angiographic left atrial volumes were compared in 19 patients with mitral valve disease, giving an excellent correlation. A moderate correlation was found between the anteroposterior dimension of the left atrium obtained using M mode echocardiography and that obtained using the parasternal short axis and long axis projections. In normal subjects a good correlation was found between SI and ML dimensions, while a lower correlation was found between SI and AP, and ML and AP dimensions. The SI dimension was the major axis of the left atrium and AP dimension the minor axis. In patients with mitral valve disease a good correlation was found between SI and ML dimensions, while SI and ML dimensions had a low correlation with AP dimensions. The AP dimension was the minor axis of the left atrium, while the SI and ML dimensions were not significantly different. All left atrial dimensions were significantly greater in patients with mitral valve disease than in normal subjects. Of 30 patients with at least one dimension increased, all three dimensions were abnormal in 16, two dimensions were increased in 10, and only one dimension was increased in four. AP, SI, and ML dimensions were abnormal in 25, 20, and 27 patients, respectively. Cross sectional echocardiography may provide a reliable estimate of left atrial dimensions. In patients with mitral valve disease a thorough examination of the left atrium using multiple cross sectional views is necessary to detect asymmetric left atrial enlargement and to measure the degree of left atrial dilatation.     

Value of shear wave elastography combined with the Toronto clinical scoring system in diagnosis of diabetic peripheral neuropathy

To evaluate the diagnostic values of shear wave elastography (SWE) alone and in combination with the Toronto clinical scoring system (TCSS) on diabetic peripheral neuropathy (DPN) in patients with type 2 diabetes mellitus (T2DM).The study included 41 DPN patients, 42 non-DPN patients, and 21 healthy volunteers. Conventional ultrasonography and SWE were performed on the 2 sides of the tibial nerves, and cross-sectional area (CSA) and nerve stiffness were measured. TCSS was applied to all patients. A receiver operating characteristic curve analysis was performed.The stiffness of the tibial nerve, as measured as mean, minimum or maximum elasticity, was significantly higher in patients in the DPN group than the other groups (P < .05). The tibial nerve of subjects in the non-DPN group was significantly stiffer compared to the control group (P < .05). There was no significant difference of the tibial nerve CSA among the 3 groups (P > .05). Mean elasticity of the tibial nerve with a cutoff of 71.3 kPa was the most sensitive (68.3%) and had a higher area under the curve (0.712; 0.602–0.806) among the 3 shear elasticity indices for diagnosing DPN when used alone. When combining SWE with TCSS in diagnosing DPN, the most effective parameter was the EMax, which yielded a sensitivity of 100.00% and a specificity of 95.24%.SWE is a better diagnostic tool for DPN than the conventional ultrasonic parameter CSA, and a higher diagnostic value is attained when combining SWE with TCSS.     

Cross sectional echocardiographic assessment of left ventricular volume and ejection fraction in patients with tetralogy of Fallot. Comparison with biplane angiographic measurements

To evaluate the usefulness and accuracy of calculating left ventricular volume and ejection fraction from cross sectional echocardiograms in patients with tetralogy of Fallot, 28 patients were studied within 24 hours of cineangiography. Indexed end diastolic and end systolic volumes were calculated from three different paired echocardiographic projections: (a) the two and four chamber views from the apical impulse window, (b) the parasternal long axis view and the subxiphoid long axis view, and (c) the four chamber view and short axis precordial views at mitral and papillary muscle level. Volumes were calculated in five different ways using three different algorithms (area length, Simpson's rule, the Parisi formula). The results were compared with data obtained from biplane angiograms using Graham's formula. The correlation varied with the algorithm used: the best results were obtained with the area length method using the parasternal long axis view and the sub-xiphoid view. The correlation was less accurate for the ejection fraction. The second best correlation was obtained with the area length method using the two and four chamber apical views; the other correlations were less satisfactory. Thus these results show that left ventricular volumes can be accurately assessed by cross sectional echocardiography in children with tetralogy of Fallot and that the ejection fraction can be satisfactorily estimated. The results depend on careful gain setting and precise demonstration of the left ventricular endocardium, which is best seen in the sub-xiphoid and long axis views.     

Cross sectional echocardiographic assessment of left ventricular volume and ejection fraction in patients with tetralogy of Fallot. Comparison with biplane angiographic measurements.

To evaluate the usefulness and accuracy of calculating left ventricular volume and ejection fraction from cross sectional echocardiograms in patients with tetralogy of Fallot, 28 patients were studied within 24 hours of cineangiography. Indexed end diastolic and end systolic volumes were calculated from three different paired echocardiographic projections: (a) the two and four chamber views from the apical impulse window, (b) the parasternal long axis view and the subxiphoid long axis view, and (c) the four chamber view and short axis precordial views at mitral and papillary muscle level. Volumes were calculated in five different ways using three different algorithms (area length, Simpson's rule, the Parisi formula). The results were compared with data obtained from biplane angiograms using Graham's formula. The correlation varied with the algorithm used: the best results were obtained with the area length method using the parasternal long axis view and the sub-xiphoid view. The correlation was less accurate for the ejection fraction. The second best correlation was obtained with the area length method using the two and four chamber apical views; the other correlations were less satisfactory. Thus these results show that left ventricular volumes can be accurately assessed by cross sectional echocardiography in children with tetralogy of Fallot and that the ejection fraction can be satisfactorily estimated. The results depend on careful gain setting and precise demonstration of the left ventricular endocardium, which is best seen in the sub-xiphoid and long axis views.     

Magnetic resonance velocity mapping of normal transtricuspid velocity profiles

To investigate the velocity profiles of transtricuspid inflow, we examined 20 normal subjects (17 males and 3 females, mean age 27 ± 7) by the magnetic resonance imaging (MRI). Electrocardiographic gating was performed in all anatomical and flow studies, and sequences were triggered by the R wave. Cine gradient echo images (echo time, 14 ms) were acquired in the right ventricular horizontal long axis, and from these, cine images with velocity mapping were obtained in the short axis of the right ventricle. Velocity mapping of right ventricular inflow was obtained at peak early diastolic filling. Velocity profile curves across the tricuspid inflow were obtained at each 1 cm interval from the tricuspid ring to 3 cm into the cavity. Maximum/mean velocity was 1.1 ± 0.1 at ring level, unchanged at 1 cm from the tricuspid ring, and thereafter increased to 1.4 ± 0.3 at 2 cm, and 1.5 ± 0.3 at 3 cm as peak velocity fell. The ratio of the longest and shortest jet width cross section was 1.3 ± 0.3 at ring level, and increased to 1.5 ± 0.3 at 3 cm from ring level. Jet cross sectional area was 10.4 ± 2.1 cm² at ring level, and was unchanged at 3 cm level. Thus, tricuspid inflow velocity showed a relatively flat profile at the tricuspid ring and tip level, becoming more dispersed at 2 and 3 cm from the ring. Right ventricular inflow jet cross section was elliptic, and appeared to be relatively constant in the cross- sectional area.     

Shear wave elastography of the scalene muscles in healthy adults: A preliminary study

The aim of the study is to evaluate the reliability of shear wave elastography to assess the anterior and middle scalene muscles in healthy adult subjects.The study included 60 scalene muscles in 15 healthy subjects. High-resolution ultrasound and shear wave elastography were used to evaluate the anterior scalene and the middle scalene muscles. Stiffness values were measured.The mean shear elastic modulus showed the following values, right anterior scalene muscle 18.83 ± 5.32 kPa, left anterior scalene muscle 21.71 ± 4.8 kPa, right middle scalene muscle 12.84 ± 5.2 kPa, left middle scalene muscle 19.76 ± 5.30 kPa. Positive correlation was noted between the left middle scalene muscle and body mass index (P = .004). No difference in elasticity was noted between the right and left anterior scalene muscles; however, significant difference was noted between the right and left middle scalene muscles (P = .002).The results obtained in our study could be a reference point for future research considering different scalene muscle pathologies.     

Multidetector‐row Computed Tomography Evaluation of Bilateral Bronchial Narrowing Associated with Increased Pulmonary Blood Flow in Children with Congenital Heart Disease

Background. Quantitative assessment of bilateral bronchial narrowing in children with congenital heart disease (CHD) with a left‐to‐right shunt has not yet been reported. Objective. In the present study, main bronchial size was evaluated bilaterally in normal subjects using multidetector‐row computed tomography (MDCT), and the feasibility for diagnosis of bronchial narrowing in children with CHD associated with increased pulmonary blood flow was investigated. Material and Methods. The short‐axis diameter, long‐axis diameter, and the cross‐sectional area of the bilateral bronchi were measured immediately proximal to the origin of the superior lobar branch in 86 children aged 1–52 months. Subjects were divided into three groups as follows: group 1 (normal subjects; n = 52), group 2 (asymptomatic left‐to‐right shunt group; n = 25), and group 3 (symptomatic left‐to‐right shunt group with respiratory insufficiency; n = 9). Results. Age, height, weight, and body surface area were significantly correlated with short‐ and long‐axis bronchial diameters, and bronchial cross‐sectional area in group 1. In group 2, the left bronchial cross‐sectional area was significantly lower than group 1 (P < .001), whereas the right bronchial area was not significantly different. In group 3, the right bronchial area was significantly lower than that in groups 1 and 2 (P < .05). Although the left bronchial area in group 3 was significantly lower than in group 1 (P < .001), it was not significantly different from that in group 2. Conclusion. Our study suggests that MDCT can be used to quantify bilateral bronchial narrowing. Left main bronchial obstruction develops during the early stage of heart failure, followed by the development of right bronchial narrowing.     

Influence of age and end-stage renal disease on the stiffness of carotid wall material in hypertension

BACKGROUND: Incremental elastic modulus, which is the slope of the relationship between stress and strain of arterial vessels, is a marker of wall material stiffness. The radial artery incremental elastic modulus, which is not influenced by age, is normal or reduced in patients with essential hypertension but increased in patients with end-stage renal disease. Authors of studies on hypertension largely ignore the question of whether the incremental elastic modulus, measured in the common carotid artery as typical of a central artery site, differs according to age or to the presence of end-stage renal disease or both. SUBJECTS AND METHODS: The carotid incremental elastic modulus was measured in 208 hypertensive patients divided into four groups according to age (< or = or > 55 years) and the presence or absence of end-stage renal disease. The incremental elastic modulus was calculated from transcutaneous measurements of arterial internal diameter and wall thickness (echo-tracking device) and carotid pulse pressure (tonometry). Because the four groups of subjects had the same mean arterial pressure, the static incremental elastic modulus was calculated both in isobaric conditions and for the same wall stress. RESULTS: In nonuremic subjects, lumen diameter, wall thickness and the incremental elastic modulus were significantly (P < 0.001) increased in older subjects whereas compliance and distensibility were decreased. The mean (+/- SD) elastic modulus was 0.41 +/- 0.14 x 10(3) kPa in younger and 0.71 +/- 0.28 x 10(3) kPa in older subjects. In uremic subjects, the corresponding values were 0.48 +/- 0.30 and 0.90 +/- 0.49 x 10(3) kPa, and therefore higher than in nonuremic subjects, irrespective of age. Multiple regression analysis showed that age, mean arterial pressure and the presence of end-stage renal disease independently influenced carotid diameter, distensibility and the incremental elastic modulus. CONCLUSIONS: In hypertensive patients, the carotid incremental elastic modulus is increased independently in aging men and women and in the presence of uremia. This increase is not dependent on mechanical factors such as the level of mean blood pressure.     

原发性高血压患者是否伴有心房颤动左心重塑对比

探讨伴发心房颤动 (简称房颤 )的高血压患者左室肥厚性重塑 ,左室、左房几何形状重塑与未发生房颤的高血压病患者之间的异同。顺序门诊或住院的原发性高血压患者 ,排除对心脏几何结构有影响的疾病及其他原因导致的房颤。将患者分为两组 :原发性高血压无房颤组 (EH组 )和原发性高血压伴房颤组 (EHAF组 )。行超声心动图检测左室舒张末期长径、心尖四腔横径、左房横径和左房面积、左室室间隔厚度 (IVST)、左室后壁厚度 (PWT)、左室舒张末期内径 (EDD)、左房前后径和左房长径。计算 :IVST/PWT比值、左室横 /长径比值、左房平均横 /长径比、左房室平均横径比和左房室长径比。同时测量身高和体重 ,计算体重指数和左室质量指数 (LVMI)。结果 :EH组入选患者 4 4 6例 ,EHAF组 78例 ,EHAF组比EH组年龄大 (P <0 .0 1)。EHAF组IVST、LVMI明显大于EH组(P <0 .0 5和 0 .0 1) ,EHAF组左室心尖四腔横径大于EH组 (P <0 .0 5 ) ,左室长径和EDD两组间无明显差异 ,E HAF组左室横 /长径比值大于EH组 (P <0 .0 5 )。EHAF组左房各内径和面积均明显大于EH组 (P <0 .0 1) ,左房平均横 /长径比EHAF组小于EH组 (P <0 .0 1)。左房室平均横径比及左房室长径比EHAF组均明显大于EH组(P <0 .0 1)。结论 :高血压伴房颤者左室肥厚性重塑严?     

Correlation between markers of peripheral nerve function and structure in type 1 diabetes

Background

Clinical and experimental studies in patients with type 1 and type 2 diabetes have demonstrated changes in ion channel function and nerve structure. In this study, we investigated the relationship between axonal dysfunction and morphological change in diabetic polyneuropathy by using neuromuscular ultrasound and nerve excitability techniques. We also explored possible differences in this relationship between type 1 and type 2 diabetes.

Methods

Nerve ultrasound and corresponding motor excitability studies were undertaken in 110 diabetes patients (50 type 1; 60 type 2) and 60 age‐matched controls (30 for each group). Neuropathy severity was assessed by using total neuropathy score. Median and tibial nerve cross‐sectional areas were measured at nonentrapment sites by using high‐resolution linear probe.

Results

Median and tibial nerve cross‐sectional areas were significantly higher in diabetes patients compared with controls: type 1 (median = 7.6 ± 0.2 mm² vs 6.3 ± 0.1 mm²; tibial = 14.5 ± 0.7 mm² vs 10.8 ± 0.3 mm², P < .05) and type 2 (median = 9.1 ± 0.3 mm² vs 7.2 ± 0.1 mm²; tibial = 18.5 ± 1.0 mm² vs 12.8 ± 0.5 mm², P < .05). In the type 1 cohort, significant correlations were found between nerve cross‐sectional area and excitability parameters including resting current‐threshold slope (median: r = 0.523, P < .0001; tibial: r = ?0.571, P = .004) and depolarizing threshold electrotonus at 90 to 100 ms (median: 0.424, P < .01; tibial: r = 0.435, P = .030). In contrast, there was no relationship between excitability values and nerve cross‐sectional area in the type 2 cohort.

Conclusions

This study has identified correlation between markers of axonal membrane function and structural abnormalities in peripheral nerves of type 1 diabetes patients. The differential relationship in nerve function and structure between type 1 and type 2 diabetes provides clinical evidence that different pathophysiological mechanisms underlie the development of neuropathy in these patient groups.     

Comparison of aortic elasticity determined by cardiovascular magnetic resonance imaging in obese versus lean adults

The vascular properties of large vessels in the obese have not been adequately studied. We used cardiovascular magnetic resonance imaging to quantify the cross-sectional area and elastic properties of the ascending thoracic and abdominal aorta in 21 clinically healthy obese young adult men and 25 men who were age-matched lean controls. Obese subjects had greater maximal cross-sectional area of the ascending thoracic aorta (984 +/- 252 vs 786 +/- 109 mm(2), p <0.01) and of the abdominal aorta (415 +/- 71 vs 374 +/- 51 mm(2), p <0.05). When indexed for height the differences persisted, but when indexed for body surface area, a significant difference between groups was found only for the maximal abdominal aortic cross-sectional area. The obese subjects also had decreased abdominal aortic elasticity, characterized by 24% lower compliance (0.0017 +/- 0.0004 vs 0.0021 +/- 0.0005 mm(2)/kPa/mm, p <0.01), 22% higher stiffness index beta (6.0 +/- 1.5 vs 4.9 +/- 0.7, p <0.005), and 41% greater pressure-strain elastic modulus (72 +/- 25 vs 51 +/- 9, p <0.005). At the ascending thoracic aorta, only the pressure-strain elastic modulus was different between obese and lean subjects (85 +/- 42 vs 65 +/- 26 kPa, respectively; p <0.05), corresponding to a 31% difference-but arterial compliance and stiffness index were not significantly different between groups. In clinically healthy young adult obese men, obesity is associated with increased cross-sectional aortic area and decreased aortic elasticity.     

Cross sectional echocardiographic demonstration of the mechanisms of abnormal interventricular septal motion in congenital total absence of the left pericardium.

OBJECTIVE: To investigate the influence of the absence of the pericardium on the left ventricular wall, particularly on interventricular septal motion, using M mode and cross sectional short axis echocardiography in patients with congenital total absence of the left pericardium. METHODS: 21 patients with, congenital total absence of the left pericardium were divided into three groups according to the interventricular septal motion; systolic type (n = 6) with paradoxical motion during systole, diastolic type (n = 11) with abnormal posterior motion during mid to late diastole, and mixed type (n = 4) with paradoxical motion during systole and abnormal posterior motion during diastole. RESULTS: On cross sectional short axis echocardiograms of the left ventricle, in the diastolic type the degree of angular displacement of the papillary muscles during end diastole to end systole showed excessive anticlockwise rotation about the long axis of the left ventricle without marked anteroposterior displacement. In the systolic type, there was shift of the left ventricle towards the anteromedial portion in systole and towards the posterolateral portion in diastole without significant rotation. There was a significantly positive correlation between the degree of angular displacement and the amplitude of diastolic interventricular septal motion during mid to late diastole in all patients. CONCLUSIONS: There was abnormal interventricular septal motion during systole and diastole in patients with total absence of the left pericardium. Abnormal systolic motion was induced by anteroposterior displacement of the left ventricle, and abnormal diastolic motion by left ventricular rotation about the long axis of the heart during the cardiac cycle. Analysis using cross sectional echocardiography was useful for elucidating the mechanisms of abnormal interventricular septal motion.     

Pulsed Doppler echocardiographic indices for assessing mitral regurgitation.

Pulsed Doppler indices were devised in order to grade the severity of mitral regurgitation on a quantitative basis. Indices were obtained by mapping the regurgitant jet by recording abnormal systolic Doppler signals detected on a "yes/no" basis using a 3 MHz pulsed Doppler velocimeter associated with a cross sectional real time ultrasonic scanner. Combined information from two echographic planes was used to take into account the geometrical three dimensional configuration of the jet. The following dimensions of the jet were measured: (a) the length and the height in the long axis view of the left atrium (long axis regurgitant index (LARI), 0.5 X length X height); (b) the width at the annulus in the short axis view (short axis regurgitant index (SARI); (c) the total regurgitant index (TRI) calculated as the product of LARI multiplied by SARI. Sixteen normal subjects and 94 patients including 46 cases of mitral regurgitation confirmed by angiography (32 of whom proceeded to surgery) were investigated. The diagnostic sensitivity was 91% and the specificity 94%. The jet was detected in 76% of cases. Indices were correlated with independently performed angiographic grading on a three point scale. The best linear correlation was obtained for the TRI; mean values were significantly increased for each grade of severity. Correlations with invasive procedures showed an 87% success rate for the Doppler prediction of the involved regurgitant leaflet(s) and of the anatomical site of the lesion at the annulus. In addition, an abnormal diastolic signal was found in five of the eight patients with ruptured chordae and also a decreased percentage of systolic shortening of the annulus diameter in patients with mitral regurgitation compared with those without.     

Mitral valve hypoplasia in children with isolated coarctation of the aorta.

OBJECTIVE--To test the hypothesis that isolated coarctation of the aorta is associated with relative hypoplasia of the mitral valve, even when the valve is morphologically normal. DESIGN--Cross sectional and Doppler echocardiography were used in a prospective, paired, case control study to compare mitral valve dimensions and diastolic transmitral flow characteristics as indices of left heart development. 40 children with isolated coarctation and 40 size matched controls were examined. Within the coarctation group 14 children with apical diastolic murmurs were compared with 14 size matched patients without murmurs. SETTING--A supraregional tertiary referral centre for paediatric cardiology. OUTCOME MEASURES--Mitral valve diameters, measured from the parasternal long axis, short axis, and apical four chamber views; mitral valve cross sectional area measured from the parasternal short axis view; peak early (E) and peak atrial (A) phase diastolic transmitral flow velocities measured by pulsed wave Doppler from the apical four chamber view; derived E/A ratio and pressure half time of decay from peak E. RESULTS--Mitral valve dimensions were significantly smaller in children with coarctation than in controls for long axis diameter (median 1.74 v 1.90cm, p = 0.0001), short axis diameter (2.21 v 2.28 cm, p = 0.027), and cross sectional area (2.37 v 3.15 cm2, p = 0.001). Peak E and A velocities were significantly higher in patients than in controls (0.9 v 0.82 ms-1, p = 0.013 and 0.61 v 0.51 ms-1, p = 0.007). The only difference between children with coarctation plus murmurs and those without murmurs was a marginally longer pressure half time. CONCLUSIONS--Smaller mitral valve dimensions and increased diastolic transmitral flow velocities in children with isolated coarctation compared with normal children suggests that coarctation may be part of a generalised hypoplasia of left heart structures.     

Computer analysis of cross sectional echocardiogram for quantitative evaluation of left ventricular asynergy in myocardial infarction

Left ventricular asynergy in myocardial infarction was assessed quantitatively by computer analysis of the cross sectional echocardiogram. Short axis cross sectional images of the left ventricle at the levels of the mitral valve, papillary muscle, and apex were recorded by a phased array sector scanner in 30 patients with healed myocardial infarction and 15 normal controls. Endocardial and epicardial short axis images of the left ventricle were transferred from video tape to a minicomputer through the interface circuits, then digitised and processed automatically by a minicomputer. Automatic edge detection of the endocardial and epicardial wall was performed by applying sequential steps including smoothing, second derivative technique, dynamic thresholding, and approximation of boundaries by a spline curve. To quantify regional wall motion, the short axis cross sectional left ventricular wall of each level was divided into eight octants with eight axes at 45 degrees angles from the initial standard axis which was constructed from the geometric centre of the end diastolic left ventricular cavity to the posterior end of the right side of the interventricular septum. Segmental hemiaxis, segmental area, segmental wall thickness, and those changes during cardiac cycle were measured and calculated in each segment automatically by a computer. Regional contractility of the left ventricle was evaluated by percentage systolic changes of the segmental hemiaxis, area, and wall thickness. These values were significantly reduced in the infarcted left ventricular wall as defined by left ventriculography and electrocardiography. Moreover, percentage hemiaxis changes obtained by quantitative left ventriculography described by Herman and colleagues correlated well with those using our analytical method of cross sectional echocardiography in the corresponding segments. The geometric centre of the left ventricular cavity determined by the computer moved slightly towards the anterior wall during systole in normal subjects, possibly reflecting the anterior swinging motion of the heart. The geometric centre of the left ventricular cavity in myocardial infarction moved towards the infarcted wall, showing that the floating reference system was inferior to the fixed reference system for the quantification of abnormal wall motion in myocardial infarction. In conclusion, a computer analysis of the short axis cross sectional echocardiogram of the left ventricle using the fixed reference system has shown its ability to evaluate left ventricular contraction abnormalities, especially systolic wall thickening, which is relatively free of arbitrary interpretation of the wall motion caused by the anterior swinging motion of the heart.     

Computer analysis of cross sectional echocardiogram for quantitative evaluation of left ventricular asynergy in myocardial infarction.

Left ventricular asynergy in myocardial infarction was assessed quantitatively by computer analysis of the cross sectional echocardiogram. Short axis cross sectional images of the left ventricle at the levels of the mitral valve, papillary muscle, and apex were recorded by a phased array sector scanner in 30 patients with healed myocardial infarction and 15 normal controls. Endocardial and epicardial short axis images of the left ventricle were transferred from video tape to a minicomputer through the interface circuits, then digitised and processed automatically by a minicomputer. Automatic edge detection of the endocardial and epicardial wall was performed by applying sequential steps including smoothing, second derivative technique, dynamic thresholding, and approximation of boundaries by a spline curve. To quantify regional wall motion, the short axis cross sectional left ventricular wall of each level was divided into eight octants with eight axes at 45 degrees angles from the initial standard axis which was constructed from the geometric centre of the end diastolic left ventricular cavity to the posterior end of the right side of the interventricular septum. Segmental hemiaxis, segmental area, segmental wall thickness, and those changes during cardiac cycle were measured and calculated in each segment automatically by a computer. Regional contractility of the left ventricle was evaluated by percentage systolic changes of the segmental hemiaxis, area, and wall thickness. These values were significantly reduced in the infarcted left ventricular wall as defined by left ventriculography and electrocardiography. Moreover, percentage hemiaxis changes obtained by quantitative left ventriculography described by Herman and colleagues correlated well with those using our analytical method of cross sectional echocardiography in the corresponding segments. The geometric centre of the left ventricular cavity determined by the computer moved slightly towards the anterior wall during systole in normal subjects, possibly reflecting the anterior swinging motion of the heart. The geometric centre of the left ventricular cavity in myocardial infarction moved towards the infarcted wall, showing that the floating reference system was inferior to the fixed reference system for the quantification of abnormal wall motion in myocardial infarction. In conclusion, a computer analysis of the short axis cross sectional echocardiogram of the left ventricle using the fixed reference system has shown its ability to evaluate left ventricular contraction abnormalities, especially systolic wall thickening, which is relatively free of arbitrary interpretation of the wall motion caused by the anterior swinging motion of the heart.     

Deformability of the erythrocyte membrane in patients with myelodysplastic syndromes.

One of the major determinants of erythrocyte survival is membrane deformability, and an important intrinsic parameter of membrane deformability is the shear elastic modulus (mu) with higher mu values corresponding to increased membrane rigidity. Using a micropipette technique, we determined the shear elastic modulus of erythrocytes from 21 patients with myelodysplastic syndromes (MDS). Ten thalassemic patients and 15 healthy subjects served as controls. The shear elastic modulus of MDS erythrocytes was very significantly increased in all the patients studied, reflecting the rigidity of the membrane; the value of mu was also significantly higher in comparison with thalassemic cells. These data point to a fundamental change in the mechanical properties of the erythrocyte membrane in MDS. Biochemical studies of the membrane composition are clearly needed.     

Quantitative two dimensional echocardiography during bicycle exercise in normal subjects

A quantitative two dimensional echocardiographic study was conducted in 10 normal subjects performing bicycle exercise in a supine position. Standardized two dimensional echocardiographic short axis and apical views of the left ventricle were analyzed to derive left ventricular sectional areas and length. Over a range of exercise heart rates from 108 to 152 beats/min, satisfactory two dimensional echocardiographic views and measurements were obtained for quantitative assessment of sectional and global left ventricular function. Variability of left ventricular short axis area measurements ranged from 2.9 to 8.3 percent. Left ventricular volume reconstruction employed a simplified formula ($\text{volume}\text{=}\text{5}\text{6}\text{area x length}$) X length) with a single papillary muscle level short axis area and left ventricular length. Changes in left ventricular function from rest to exercise quantitated by two dimensional echocardiography indicated a significant reduction in end-systolic volume (from 28.1 ± 5.6 to 20.8 ± 4.3 cc/m², p < 0.001) and increased left ventricular ejection fraction (from 63.4 ± 6.3 to 72.1 ± 5.7 percent, p < 0.001). The change in end-diastolic volume was not significant.It is concluded that standardized two dimensional echocardiographic study during supine bicycle exercise in normal subjects provides good reproducibility of measurements of sectional and global left ventricular function. Quantitative two dimensional echocardiographic exercise study of global as well as segmental left ventricular performance in patients may be feasible using standardized procedure and analysis.