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[en] Antagonistic muscle pairs pulling on a joint are in general able to modulate stiffness through co-activation. Closer analysis of the stiffness, however, shows that, depending on the muscle and joint parameters, domains might occur in joint angle space for which stiffness variation is limited (low stiffness variability) or even impossible (stiffness nodes). As a consequence, stiffness control utilizing pure co-activation might fail. This work presents novel strategies for simultaneous control of torque and stiffness in a hinge joint actuated by two antagonistic muscle pairs. One strategy handles stiffness nodes by shifting them away from the current joint position and thus regaining stiffness controllability. To prevent domains of low stiffness variation, an optimal muscle configuration is sought and finally defined which allows for a maximal stiffness variation across a wide joint angle range. Based on this optimal configuration, four additional control strategies are proposed and tested which deliver stiffnesses and torques comparable to those obtained in the optimal case. The strategies combine torque control and stiffness control by co-activation with novel ideas like activation overflow and an inverse model approach. All strategies are tested in simulation and the results are compared with those of the optimal setup.
[en] The 'Two-chambered right ventricle' is a rare, but unique congenital cardiac anomaly characterized by subdivision of the right ventricle into proximal high pressure chamber and distal low pressure chamber by hypertrophied aberrant muscle bundles. The aberrant muscle bundles traverse the right ventricle from the region of crista supraventricular is to the lower part of the anterior wall of the right ventricle. The ' Two-chambered right ventricle' is usually associated with other congenital cardiac anomalies such as ventricular septal defect, pulmonary valvular stenosis, etc. Therefore this anomaly could be mistakenly diagnosed as Tetralogy of Fallot or isolated interventricular septal defect. The need to separate this entity from other types of infundibular stenosis is emphasized because of the important surgical implications. Authors recently experienced a case of the Two-chambered right ventricle' resulting from aberrant muscle bundles, that are associated with other cardiac anomalies i.e., pulmonary valvular stenosis, aysplastic tricuspid valve with regurgitation and partial anomalous pulmonary venous return to the right atrium. Here we present the findings of E.K.G., cardiac catheterization, simple chest pa, cine-right ventriculography, and autopsy together with a review of related articles.
[en] Objectives: To evaluate the clinic value of ultrasound (US) in the diagnosis of muscle herniation. Methods: This retrospective study was performed on 26 patients with muscle herniation confirmed by surgery. All patients were examined by US and magnetic resonance imaging (MRI) preoperatively. The final histopathologic findings were retrospectively compared with the results of US and MRI. Results: The accuracy of ultrasonography and MRI were 92.3%(24/26) and 84.6%(22/26) respectively. There was no significant difference between two methods (χ2 = 0.25, P > 0.05). Conclusions: US can be used to observe the shape, size, location, internal echo and fascial defect of the mass of muscle herniation in a dynamical way. Ultrasound is a convenient method with high accuracy, it can be used as the first choice of imaging modality for the diagnosis of muscle herniation.
[en] Objective: The purpose of our study was to demonstrate that ultrasonography may allow a precise assessment of the course and relationships of the spinal accessory nerve (SAN). Material and methods: This study, initially undertaken in 7 cadavers, was followed by high-resolution ultrasonographic study in 15 volunteers (30 nerves) by two radiologists in consensus. The location, course and relations to the adjacent anatomic structures of the SAN were analyzed. Results: The precise course of the SAN between the lateroposterior border of the sternocleidomastoid muscle and the anterior border of the trapezius muscle could be identified by high-resolution ultrasonography. In contrast, clinical bone landmarks were not found helpful for the identification of the nerve. Conclusion: The SAN can be clearly depicted by means of ultrasonography. Knowledge of the nerve's precise location, which may evidence individual variations, may have useful clinical applications
[en] Poland's syndrome is a rare congenital anomaly characterized by partial or complete absence of the pectoralis major muscle. We report a case of Poland's syndrome in which the pectoralis major muscle was not visualized on mammography and absence of it was confirmed by ultrasonography.
[en] Background: Bladder cancer is the second most common genitourinary malignancy, Non-muscle invasive bladder cancer (NMIBC) accounts for about 75% to 80% of all bladder cancer cases; transurethral resection of bladder tumors (TURBT) is the first and gold standard treatment option for NMIBC. The most common used follow-up strategy includes cystoscopy and uriiiecytology every 3 months For 2 years, then every 6 months for the second 2 years, then yearly thereafter Aim: The aim of the present prospective study is to evaluate and analyse the efficacy of CT virtual cystoscopy in follow up of the patients with non-muscle invasive bladder cancer and this is achieved by comparison between results of virtual cystoscopy and conventional cystoscopy in these patients as regard sensitivity and specificity and correlation of these results to the size, site and shape of the tumors. Patients and Methods: The study was done over 3 years from 4/2010 to 6/2013,thirty patients were selected from inpatients of El- Demerdash Hospital Ain Shams University and the examination was performed at Misr Radiology center and massara radiology center. All the patients underwent both conventional and virtual cystoscopy .Results were compared together as regard the sensitivity and the specificity in correlation with the site, size and shape of the tumour. Results: CT virtual cystoscopy is a promising technique to use in bladder tumour detection and some other bladder lesions. However, the detection rate for recurrent NMIBC is not adequate to replace conventional cystoscopy. Conclusion: It is a promising tool that may be incorporated into the follow up scheme of non-muscle invasive bladder cancers, especially in low stage low-grade tumours (TaGl), where there is low risk of progression, where missed recurrent masses will not endanger the patient's life
[en] To evaluate the long-term results following eccentric calf-muscle training in patients with chronic Achilles tendinopathy. A total of 24 patients with chronic Achilles tendinopathy were included in a study evaluating MRI findings and clinical symptoms before and after 3 months of daily eccentric calf-muscle strength training. Median duration of symptoms was 18 months (range 6-120). Four of the patients did not perform the prescribed treatment for different reasons and were followed for 14 months. The resulting 20 treated patients completed 4.2-year (range 29-58 months) follow up. Tendon volume was evaluated by using 3D seed growing technique and signal abnormalities were visually semi-quantitatively graded. Level of pain and performance was categorized using a questionnaire completed by the patient. In the symptomatic treated patients, median intensity level of pain decreased from moderate/severe at time of inclusion to mild at follow up (p < 0.05). Median level of performance increased from severe impairment at time of inclusion to normal at follow up (p < 0.05). 12 out of 20 patients had raised intratendinous signal at time of inclusion compared to 2 out of 20 patients at follow up (p < 0.001). Mean tendon-volume measured 6.7 cm3 (SD 2.0) at time of inclusion and 6.4 cm3 (SD 2.0) at follow up (p = 0.18). The four symptomatic non-treated tendons did not improve regarding pain, performance, intratendinous signal or tendon volume. We found decreased pain, improved performance and decreased intratendinous signal both compared to index examination and immediately after the 3 months training regimen in a 4.2-year clinical and MRI follow up, in a group of patients treated with heavy loaded eccentric calf-muscle training for chronic Achilles tendinopathy. The improvements were greater at 4.2-year follow up, despite no further active treatment, than immediately after the treatment. This may indicate a good long-term prognosis for Achilles tendinosis patients. (orig.)
[en] 6 cases of rectus sheath hematoma were correctly diagnosed by ultrasound. 2 cases had bilateral rectus sheath hematoma and 4 cases were unilateral. On ultrasound finding, relatively well defined oval or spindle like cystic mass situated in the area of rectus muscle on all cases. Ultrasound examination may give more definite diagnosis and extension rectus sheath hematoma and also helpful to follow up study of hematoma