Transcatheter closure of a mid-muscular ventricular septal defect with an amplatzer VSD occluder device. (1/75)

A 5 year old girl with a haemodynamically significant mid-muscular ventricular septal defect (VSD) had successful transcatheter closure using the Amplatzer VSD occluder. This device passes through a small diameter sheath and can be easily retrieved or repositioned. These properties may make it a suitable device for closure of large mid-muscular defects in small children.  (+info)

Should initial clamping for abdominal aortic aneurysm repair be proximal or distal to minimise embolisation? (2/75)

OBJECTIVES: to determine whether clamping proximally or distally on the infrarenal aorta during abdominal aortic aneurysm (AAA) repair increases the overall embolic potential. MATERIALS AND METHODS: a sheath was placed in the mid-infrarenal aorta of 16 dogs. In eight animals a cross-clamp was placed at the aortic trifurcation, and in another eight animals it was placed in the immediate subrenal position. Under fluoroscopy blood flow within the infrarenal aorta was evaluated by contrast and particle injections. Grey-scale analysis was used to calculate contrast density. Particle distribution was followed fluoroscopically and confirmed pathologically. RESULTS: fifty-seven+/-24% of injected contrast remained within the aorta with distal clamping while 97+/-7% did so with proximal clamping (p<0.01). With distal aortic clamping 6.2+/-1. 3 out of 10 injected particles remained within the aorta after 15 seconds and only 0.8+/-0.8 remained after 5 min. With proximal aortic clamping, all 10 of the particles remained within the aortic lumen for the full 5 minutes (p<0.001). CONCLUSIONS: initial distal clamping minimises distal embolisation, but may result in renal and/or visceral embolisation. Initial proximal clamping prevents proximal embolisation and does not promote distal embolisation. We recommend initial proximal clamping in aortic aneurysm surgery to minimise the overall risk of embolisation.  (+info)

A CT method to measure hemodynamics in brain tumors: validation and application of cerebral blood flow maps. (3/75)

BACKGROUND AND PURPOSE: CT is an imaging technique that is routinely used for evaluating brain tumors. Nonetheless, imaging often cannot show the distinction between radiation necrosis and neoplastic growth among patients with recurrent symptoms after radiation therapy. In such cases, a diagnostic tool that provides perfusion measurements with high anatomic detail would show the separation between necrotic areas, which are characterized by low perfusion, from neoplastic areas, which are characterized by elevated CBF. We attempted to validate a dynamic contrast-enhanced CT method for the measurement of regional CBF in brain tumors, and to apply this method by creating CBF maps. METHODS: We studied nine New Zealand White rabbits with implanted brain tumors. We obtained dynamic CT measurements of CBF, cerebral blood volume (CBV), and permeability surface (PS) from the tumor, peritumor, and contralateral normal tissue regions. In all nine rabbits (two studies per rabbit), we compared CT-derived CBF values with those simultaneously obtained by the standard of reference ex vivo microsphere technique. Using CT, we examined three rabbits to assess the variability of repeated CBF and CBV measurements; we examined the other six to evaluate regional CBF reactivity to arterial carbon dioxide tensions. Finally, CT CBF maps were obtained from a rabbit with a brain tumor during normocapnia and hypocapnia. RESULTS: We found a significant linear correlation (r = 0.847) between the regional CT-and microsphere-derived CBF values, with a slope not significantly different from unity (0.99+/-0.03, P>.01). The mean difference between regional CBF measurements obtained using both methods did not significantly deviate from zero (P>.10). During normocapnia, tumor had significantly higher CBF, CBV, and PS values (P<.05) than did peritumor and normal tissues. The variability in CT-derived CBF and CBV measurements in the repeated studies was 13% and 7%, respectively. CT revealed no significantly different CBF CO2 reactivity from that determined by the microsphere method (P>.10). The CBF map of tumor regions during normocapnia showed much higher flow than normal regions manifested, and this difference was reduced on the hypocapnia CBF map. CONCLUSION: The dynamic CT method presented herein provides absolute CBF measurements in brain tumors that are accurate and precise. Preliminary CBF maps derived with this method demonstrate their potential for depicting areas of different blood flow within tumors and surrounding tissue, indicating its possible use in the clinical setting.  (+info)

Papillary muscle shortening in the intact dog; a cinderadiographic study of tranquilized dogs in the upright position. (4/75)

Shortening of the anterior papillary muscle of the left ventricle was demonstrated in six intact, tranquilized dogs. Two small metal markers that had been surgically implanted 3-50 months earlier were cineradiographically photographed during approximately ten sequential cardiac cycles in each of two orthogonal positions. Distances between markers were plotted for successive frames. The resulting curves were used to obtain maximum velocities of papillary muscle shortening and lengthening: 1.08 plus or minus 0.29 muscle lengths/sec and 1.39 plus or minus 0.48 muscle lengths/sec, respectively. From the two orthogonal planes, the average maximum spatial distance and the average minimum spatial distance between the markers were calculated. The mean percent shortening of 22.8 plus or minus 6.5% was surprisingly large: it approximated the distance from the foot to the peak of the ascending limb of the myocardial length-tension curve derived from isolated muscle studies. Mechanical studies on isolated papillary muscle have consistently shown reduced shortening with increasing loads. Since the in vivo dog papillary muscle has been reported to be under considerable tension during systole, there appears to be some contradiction between the degree of shortening found in the present study and the shortening observed in isolated papillary muscle studies.  (+info)

Cricopharyngeal myotomy: treatment of dysphagia. (5/75)

Six patients are presented who underwent cricopharyngeus myotomy for dysphagia. The clinical history and cine studies appear to be the most useful assessments in defining patients with dysphagia who may improve after a myotomy. Etiological factors which may precipitate poor coordination of the swallowing mechanism and a relative cricopharyngeus muscle obstruction include neuromuscular disorders, radical oral surgery, central nervous disease, and idiopathic disorders, although the exact physiology of the cricopharyngeus muscle in health and disease is not as yet delineated, the muscle is being implicated in many problems as the inciting factor of upper esophageal dysphagia. The operation of cricopharyngeus myotomy is a relatively simple procedure and should be done with little morbidity and mortality in properly selected cases.  (+info)

Basic limb kinematics of small therian mammals. (6/75)

A comparative study of quantitative kinematic data of fore- and hindlimb movements of eight different mammalian species leads to the recognition of basic principles in the locomotion of small therians. The description of kinematics comprises fore- and hindlimb movements as well as sagittal spine movements including displacement patterns of limb segments, their contribution to step length, and joint movements. The comparison of the contributions of different segments to step length clearly shows the proximal parts (scapula, femur) to produce more than half of the propulsive movement of the whole limb at symmetrical gaits. Basically, a three-segmented limb with zigzag configuration of segments is mainly displaced at the scapular pivot or hip joint, both of which have the same vertical distance to the ground. Two segments operate in matched motion during retraction of the limb. While kinematic parameters of forelimbs are independent of speed and gait (with the scapula as the dominant element), fundamental changes occur in hindlimb kinematics with the change from symmetrical to in-phase gaits. Forward motion of the hindlimbs is now mainly due to sagittal lumbar spine movements contributing to half of the step length. Kinematics of small therian mammals are independent of their systematic position, their natural habitat, and also of specific anatomical dispositions (e.g. reduction of fingers, toes, or clavicle). In contrast, the possession of a tail influences 'pelvic movements'.  (+info)

Torque patterns of the limbs of small therian mammals during locomotion on flat ground. (7/75)

In three species of small therian mammals (Scandentia: Tupaia glis, Rodentia: Galea musteloides and Lagomorpha: Ochotona rufescens) the net joint forces and torques acting during stance phase in the four kinematically relevant joints of the forelimbs (scapular pivot, shoulder joint, elbow joint, wrist joint) and the hindlimbs (hip joint, knee joint, ankle joint, intratarsal joint) were determined by inverse dynamic analysis. Kinematics were measured by cineradiography (150 frames s(-1)). Synchronously ground reaction forces were acquired by forceplates. Morphometry of the extremities was performed by a scanning method using structured illumination. The vector sum of ground reaction forces and weight accounts for most of the joint force vector. Inertial effects can be neglected since errors of net joint forces amount at most to 10 %. The general time course of joint torques is comparable for all species in all joints of the forelimb and in the ankle joint. Torques in the intratarsal joints differ between tailed and tail-less species. The torque patterns in the knee and hip joint are unique to each species. For the first time torque patterns are described completely for the forelimb including the scapula as the dominant propulsive segment. The results are compared with the few torque data available for various joints of cats (Felis catus), dogs (Canis lupus f. familiaris), goats (Capra sp.) and horses (Equus przewalskii f. caballus).  (+info)

Clinical significance of coronary calcification. (8/75)

Coronary artery calcification (CAC) was assessed by cinefluoroscopy and its extent was scored (CAC score) in 2,163 consecutive patients undergoing coronary angiography, based on the angiographic and clinical data, the patients were categorized into 8 types of coronary artery disease (CAD). The CAC score was lowest in angiographically normal subjects (0.12+/-0.60) and highest in patients with silent myocardial ischemia (14.31+/-8.61). Risk factors for CAC were advanced age, male sex (at age <80 years), hypertension, diabetes mellitus, and a high grade of organic coronary stenosis. The CAC score in patients with acute coronary syndrome (unstable angina+acute myocardial infarction; 5.48+/-7.42) was significantly lower than that in those with chronic CAD (silent ischemia+stable angina; 9.72+/-8.73; p<0.0001), but was still higher than that in normal subjects or those with vasospastic angina (0.92+/-2.88; p<0.0001). The results indicate that CAC is a manifestation of coronary atherosclerosis and its appearance depends on the pathological type of ischemic heart disease. Fixed stenosis with a slow and chronic process tends to be associated with CAC. The clinical implication of extensive CAC in acute coronary syndrome compared with normal subjects should be further investigated.  (+info)

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