Biomedical subjects

R Maksimovic

Publications and source records attributed to R Maksimovic.

6 recordsLinked to original sources

PubMed2000

Flexible percutaneous pericardioscopy: inherent drawbacks and recent advances.

Pericardioscopy enables endoscopic inspection and aimed biopsy of the parietal and visceral pericardium. To elucidate possible technical modifications contributing to the feasibility, diagnostic value and safety of the procedure, pericardioscopy with an Olympus HYF-1T flexible endoscope was performed in 32 patients (53.1% males, mean age 46.2 +/- 13.1 years) with pericardial effusions. In all patients, the initial step of the procedure was subxiphoid fluoroscopically controlled pericardiocentesis and drainage of the pericardial effusion. An Olympus FB-41ST biopsy forceps was applied for endoscopically guided pericardial biopsies. Standard sampling was used in 22/32 patients (3 to 6 samples/patient) and extensive sampling in 10/32 patients (18 to 20 samples/patient). In additional 12 patients pericardial biopsy was performed without pericardioscopy, under fluoroscopic control. Endoscopic visualization was clearly superior when pericardial effusion was partially replaced with 100 to 300 ml of air (29/32 procedures) in comparison to 3/32 procedures in which the pericardial effusion was replaced with warm normal saline (37 degrees C). In patients with hemorrhagic effusion (12/32), we either repeatedly injected and removed 100 to 150 ml volumes of normal saline (37 degrees C), or postponed pericardioscopy for 2 to 3 days of active drainage. The specificity of endoscopic findings is low and not decisive for the diagnosis. However, pericardioscopy is significantly contributing to the diagnostic value of pericardial biopsy, especially regarding establishing the new diagnosis and etiology of the pericardial disease. Sampling efficiency was also significantly higher for procedures using aimed pericardial biopsy with standard and extensive sampling compared to procedures performed under fluoroscopy: 86.2%, 87.3%, and 43.7%, respectively. No major complications directly related to the procedure were encountered. Minor complications included: short-run ventricular tachycardia (6.3%), pain at the sheath entry site (75%) and transient fever (37.5%). In conclusion, pericardioscopy with Olympus HYF-1T, after air instillation, is a technically complex, but safe procedure that enables excellent visualization and extensive pericardial sampling with improved diagnostic value of pericardial biopsies.

Adult↗

PubMed2000

Computed tomography image analyzer: 3D reconstruction and segmentation applying active contour models--'snakes'.

Many diagnostic and therapeutic procedures depend on medical images. In order to overcome imperfections of the obtained images, which are due to the acquisition process, and to extract new information from the available images, many techniques have been developed. In this study, a new method of image segmentation and 3D reconstruction based on active contour models ('snakes') was applied in analyzing computed tomography (CT) images in patients with acute head trauma. Using this method, lesion to brain (LBR) and ventricle to brain ratio (VBR) parameters, as well as 3D reconstruction of traumatic lesion, was obtained accurately. In our study group, 215 patients (mean age 42.4+/-23.5 years, 138/215 (64.2%) males) were included. Among them, 72 (33.5%) did not survive during hospitalisation in the Emergency Department. LBR correlated with the Glasgow Coma Score and the intrahospital outcome (r=-0.457 and r=0.515, respectively). Besides, non-survivors had greater LTB values (0.042+/-0.034) than survivors (0.005+/-0.011). However, VBR did not correlate with these clinical parameters. In addition, LBR was significantly higher in the patients with other pathologic CT findings. The proposed methodology, based on extracting maximum information from available CT scans, could be a basis for further medical decision making in patients with acute head trauma.

Adult↗

PubMed1999

Initial clinical experience with PerDUCER device: promising new tool in the diagnosis and treatment of pericardial disease.

BACKGROUND: The idea to enter the normal pericardial sac safely was unrealistic until recently. The development of a novel instrument (PerDUCER pericardial access device) for percutaneous access to the pericardium could potentially have a significant impact, not only on patients with pericardial diseases but even more, or primarily, on diagnosis and treatment of myocardial and coronary disease and arrhythmias. HYPOTHESIS: The overall objective of the present study was to evaluate the feasibility and safety of the percutaneous pericardial access with PerDUCER in patients with pericardial disease, and to analyze our initial experience with this new technique, with particular emphasis on sequential procedural steps. METHODS: The device was studied in five patients with pericardial disease (two men, mean age 50.4 years, range 30-68, four with normal body mass index). The procedure consists of two distinct techniques: (1) access to the mediastinal space, and (2) pericardial capture, puncture, and insertion of the guidewire. Access to the mediastinal space includes the introduction of a blunt cannula, a 0.038 guidewire, a dilator-introducer sheath set, and insertion of the PerDUCER device. Key points of the PerDUCER procedure are as follows: introduction of the blunt cannula without resistance, placement of the dilator-introducer sheath at the upper third of the heart, systolic movements of the PerDUCER device, successful vacuum and capture of pericardium, puncture and introduction of the intrapericardial guidewire. RESULTS: Access to the mediastinal space was accomplished in four of five patients, as were pericardial capture and probably puncture. However, despite numerous successful captures and probably punctures of pericardium, we were not able to confirm introduction of the intrapericardial guidewire into the pericardial cavity in any of our patients (0/5). The procedure was very well tolerated in all patients (5/5). No major complications developed during the procedure, bearing in mind that the intrapericardial placement of the guidewire was not achieved. Minor complications included pain at the dilator-introducer sheath entry site (5/5) and mild transient fever (2/5). CONCLUSIONS: According to the present experience, we believe that, with minor modifications, the PerDUCER device could be successfully implemented for pericardial entry in patients with pericardial disease. Further studies are needed to evaluate the feasibility and safety of this new instrument in patients with a normal pericardium. This could open a most exciting spectrum of possible implementations of the device in the future.

Adult↗

PubMed1999

Classification of tetraplegics through automatic movement evaluation.

The general problem of classification of functional movements in humans with spinal cord injuries requires the following questions to be answered: what are the essential kinematic parameters that we have to observe during the movement? Is it possible to estimate preserved motor skills based on kinematics? Which computational method for identification is suited to geometric feature analysis? To answer these questions we have developed the methodology which has two phases: (1) recordings of a series of specified arm movements; and (2) custom made software for graphical presentation of arm movements and the design of wavelet and neural networks for movement classification. The proposed protocol is automated and both graphical presentation and neural networks allow easy interpretation of the instrumented assessment to accomplish automatic classification of arm movements in tetraplegics. The protocol was evaluated on 16 spinal cord injury (SCI) patients and seven healthy control subjects for three different arm movements. The classification rate yielded results in the range 46-100% for movement trials that were tested. The application of neural networks for classification of arm movements is completed with results using different neural networks: backpropagation, radial basis, recurrent (Elman), self-organizing and Learning Vector Quantization (LVQ).

Adolescent↗

PubMed1999

Computed tomography image analyzer: segmentation applying active contour models--"snakes".

Many diagnostic and therapeutic procedures depend on medical images. In order to overcome imperfections of obtained images which are due to acquisition process and to obtain new information from available images, many techniques have been developed. In this study relatively new method of image segmentation, active contour model--"snakes" was applied in analyzing computed tomography (CT) images in patients with acute head trauma. Using this method, lesion to brain (LBR) and ventricle to brain ratio (VBR) were obtained accurately. Quantitative variable LBR, is significantly higher in patients with other pathologic CT findings and who do not survive during hospitalization. Thus, by applying segmentation "snakes" model it is possible to extract maximum information from available CT scans. These variables could be basis for medical decision making in patients with acute head trauma.

Artifacts↗

PubMed1997

The main epidemiological, clinical and morphological features of moyamoya disease in Yugoslavia.

Over a period of 22 years, 31 Moyamoya cases have been recorded in Yugoslavia. In this group of the patients comprising four children and 27 adults, peak age incidence is in the third and fourth decades of life. Males and females have been almost equally affected. Familial cases or territorial clustering of the patients have not been noted. In most cases leading symptoms on admission were motor disturbances. In four patients unilateral involvement was observed while in 27 patients bilateral changes of the internal carotid artery were seen.

Adolescent↗