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ABSTRACT: C-arm based surgical navigation system is a kind of computer assisted surgery (CAS) system. In this paper, key techniques concerning this kind of system are presented. The key techniques mainly include XRII image distortion correction and C-arm imaging system calibration. On this basis, we designed relevant tools and made them fabricated, and developed a software system. Experimental results of human fresh spine sample showed that with the surgical navigation system, screw insertion accuracy was much higher than that without the surgical navigation system.
Sheng wu yi xue gong cheng xue za zhi = Journal of biomedical engineering = Shengwu yixue gongchengxue zazhi 04/2011; 28(2):280-3.
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ABSTRACT: XRII image distortion correction is a key technique in a C-arm-based surgical navigation system. In this paper, we present a new correction method, which integrates the method of moving least squares(MLS) and the method of multilevel B-spline approximation (MBA). Experiments show that the proposed method leads to good outcome of image correction and it is more accurate than the exsiting correction methods.
Sheng wu yi xue gong cheng xue za zhi = Journal of biomedical engineering = Shengwu yixue gongchengxue zazhi 06/2010; 27(3):548-51.
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ABSTRACT: A surgical navigation system based on X-rays of C-arm with a calibration target has been studied and developed. Extracting images of markers in the two templates on the calibration target, the system is able to establish the relationship between different markers coordinates in different coordinate systems using the algorithm based on the layout of specific markers. The correction of X-ray image distortion and C-arm camera calibration are performed using the images of calibration target as bases. After the parameters of the C-arm projection model being determined, an X-ray image of surgical site will be acquired preoperatively; the surgical instruments will be tracked by the optical position system, and then virtual projections of instruments can be formed on preoperative images. Surgeons will perform operations with the guidance of the system. The C-arm can be used less frequently and the X-ray radiation can be reduced. Cadaveric spine specimen experiments and error analysis have underpinned the clinical feasibility of the system.
Sheng wu yi xue gong cheng xue za zhi = Journal of biomedical engineering = Shengwu yixue gongchengxue zazhi 10/2009; 26(5):1106-10.
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ABSTRACT: Extracting landmark geometric data in C-arm X-ray images is a key technique of camera calibration process in a fluoroscopic-image-based surgical navigation system. The geometric data is the basis of X-ray image distortion correction and C-arm camera calibration. In this paper we present an integrated clustering algorithm for landmark geometric data extraction. This proposed alorithm, with the advantages of an adaptive thresholding method as well as of a fast quasi connected-component labeling method, needs only one pass to extract the needed geometric data in a gray scale image. It is of high executive efficiency and good robustness as well.
Sheng wu yi xue gong cheng xue za zhi = Journal of biomedical engineering = Shengwu yixue gongchengxue zazhi 11/2008; 25(5):1039-43.
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ABSTRACT: Seeing that there are several defects in the calibration target currently used in C-arm-based surgical navigation system, we propose an improved design of calibration target based on the theory of generalized mapping. The method of design is introduced, the analysis is made, and the results are reported. The newly designed calibration target is of low manufacturing difficulty and cost; with the new calibration target, the running efficiency and the image quality of the whole navigation system could be improved. The new calibration target is found to be of several advantages over the currently used ones; it is feasible and is under manufacturing already.
Sheng wu yi xue gong cheng xue za zhi = Journal of biomedical engineering = Shengwu yixue gongchengxue zazhi 09/2008; 25(4):930-3.
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ABSTRACT: To study the direct correlation between gastric dysrhythmias and in vivo gastric muscle tone.
Five healthy dogs were implanted with 4 pairs of electrodes along the greater curvature, with a strain gauge (SG) being sutured parallel to the distal electrodes (2 cm above the pylorus). Intravenous vasopressin was given to induce gastric dysrhythmia. The percentage of regular slow waves and SG energy were calculated.
(1) the regularity of gastric myoelectric activity (GMA) was reduced during and after infusion of vasopressin; (2) SG energy was significantly decreased during the infusion of vasopressin; (3) the decrease in SG energy was well correlated with the reduction in GMA regularity; (4) SG energy was negatively correlated with bradygastria and tachygastria.
Vasopressin inhibits gastric contractions and impairs gastric slow waves; gastric dysrhythmias are associated with the reduced antral muscle contractions, and are indicative of antral hypomotility.
World Journal of Gastroenterology 08/2006; 12(25):3994-8. · 2.47 Impact Factor
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ABSTRACT: The aim of this study was to investigate the anti-dysrhythmic effect of long-pulse gastric electrical stimulation (GES) in dogs.
The study was performed in 7 healthy dogs implanted with 4 pairs of serosal gastric electrodes. Each dog was studied in three sessions on 3 separate days in a randomized order with recordings of gastric slow waves. In session 1 or 2, infusion of either saline or glucagon (0.1 U/kg in 20 ml saline instilled in 40 min) was given during the 2nd and 3rd 20-min periods. The protocol of session 3 was the same as that of session 2 except that GES was performed during the 2nd 20-min period.
(1) Glucagon induced gastric dysrhythmia and decreased gastric slow-wave coupling (ANOVA, p < 0.001). The long-pulse GES normalized glucagon-induced gastric dysrhythmia and the uncoupling of slow waves. (2) Glucagon induced symptoms and behaviors suggestive of nausea and the symptoms were not improved by long-pulse GES.
(1) Glucagon induces gastric dysrhythmias, slow-wave uncoupling and symptoms, and (2) long-pulse GES normalizes glucagon-induced gastric dysrhythmia and slow-wave uncoupling with no improvement in symptoms.
Digestion 02/2004; 69(2):63-70. · 2.05 Impact Factor
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ABSTRACT: The aim of this study was to investigate the acute effects of 3 different methods of electrical stimulation in the prevention of vasopressin-induced emetic response and gastric dysrhythmias.
Seven female hound dogs chronically implanted with 4 pairs of electrodes on gastric serosa were used in a 5-session study. Saline and vasopressin were infused in sessions 1 and 2, respectively. In the other 3 sessions with vasopressin infusion, 3 different methods of electrical stimulation (short-pulse stimulation, long-pulse stimulation, and electroacupuncture) were applied. Gastric slow waves and vomiting and behaviors suggestive of nausea were recorded in each session. In a separate study, additional experiments were performed in 5 vagotomized dogs to investigate vagally mediated mechanisms.
Vasopressin induced gastric dysrhythmias, uncoupling of slow waves, and vomiting and behaviors suggestive of nausea (P < 0.02, analysis of variance). Long-pulse stimulation, but not short-pulse stimulation or electroacupuncture, was capable of preventing vasopressin-induced gastric dysrhythmias and gastric slow wave uncoupling. Short-pulse stimulation and electroacupuncture, but not long-pulse stimulation, prevented vomiting and significantly reduced the symptom scores, which was not noted in the dogs with truncal vagotomy.
Long-pulse stimulation normalizes vasopressin-induced slow wave abnormalities with no improvement in vomiting and behaviors suggestive of nausea. Short-pulse stimulation and electroacupuncture prevent vomiting and behaviors suggestive of nausea induced by vasopressin but have no effects on slow waves, and their effects are vagally mediated.
Gastroenterology 02/2003; 124(2):401-9. · 11.68 Impact Factor
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ABSTRACT: The aim of the study was to determine the effects of low-volume rectal distension on gastric myoelectrical activity. The study was performed in 14 healthy volunteers in 2 randomized sessions. In the control session, a small balloon was inserted into the rectum 10 cm beyond the anal verge and inflated with 20 ml of air. Gastric myoelectrical activity was recorded for 30 minutes in the fasting state and 30 minutes after a meal; and then the balloon was deflated and removed, and another 30-min recording was followed. The study session was the same except that after the 30-min baseline recording the balloon was inflated to reach a volume with which the subject felt an urgency for defecation. Spectral analyses were performed to compute the dominant frequency, power, and regularity (2-4 cycles/minutes, cpm) of the gastric slow waves and the percentage of gastric dysrhythmia. RESULTS: 1). In comparison with our previously published data, the placement of the rectal balloon with a volume of 20 ml air did not affect the regularity of the slow waves (84.2 +/- 3.6% in fasting, 85.3 +/- 4.3% in fed); In comparison with the control session, the rectal distension inducing an urgency for defecation (average volume of air: 72.5 ml) significantly reduced the regularity of gastric slow waves in the fed state (72.0 +/- 5.7%, P < 0.03 vs baseline; P < 0.02, vs control session) but not in the fasting state (80.1 +/- 4.5%, P = 0.1). This postprandial change was attributed to a significant increase in bradygastria (3.1 +/- 1.0% vs 7.9 +/- 2.6%, P < 0.04) and a marginal increase in tachygastria (7.4 +/- 2.5% vs 15.8 +/- 4.3%, P = 0.06). The normal postprandial increases in the dominant frequency and power of the gastric slow wave were abolished in both sessions. conclusions, rectal distension evoking an urgency for defecation impairs postprandial gastric slow waves with an increase in the percentage of both bradygastria and tachygastria.
Digestive Diseases and Sciences 12/2002; 47(11):2473-9. · 2.12 Impact Factor
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ABSTRACT: The aim of the study was to determine the effects of low-volume rectal distension on gastric myoelectrical activity. The study was performed in 14 healthy volunteers in 2 randomized sessions. In the control session, a small balloon was inserted into the rectum 10 cm beyond the anal verge and inflated with 20 ml of air. Gastric myoelectrical activity was recorded for 30 minutes in the fasting state and 30 minutes after a meal; and then the balloon was deflated and removed, and another 30-min recording was followed. The study session was the same except that after the 30-min baseline recording the balloon was inflated to reach a volume with which the subject felt an urgency for defecation. Spectral analyses were performed to compute the dominant frequency, power, and regularity (2–4 cycles/minutes, cpm) of the gastric slow waves and the percentage of gastric dysrhythmia. Results: 1). In comparison with our previously published data, the placement of the rectal balloon with a volume of 20 ml air did not affect the regularity of the slow waves (84.2 3.6% in fasting, 85.3 4.3% in fed); In comparison with the control session, the rectal distension inducing an urgency for defecation (average volume of air: 72.5 ml) significantly reduced the regularity of gastric slow waves in the fed state (72.0 5.7%, P < 0.03="" vs="" baseline;="">P < 0.02,="" vs="" control="" session)="" but="" not="" in="" the="" fasting="" state="" (80.1="" ="" 4.5%,="">P = 0.1). This postprandial change was attributed to a significant increase in bradygastria (3.1 1.0% vs 7.9 2.6%, P < 0.04)="" and="" a="" marginal="" increase="" in="" tachygastria="" (7.4="" ="" 2.5%="" vs="" 15.8="" ="" 4.3%,="">P = 0.06). The normal postprandial increases in the dominant frequency and power of the gastric slow wave were abolished in both sessions. conclusions, rectal distension evoking an urgency for defecation impairs postprandial gastric slow waves with an increase in the percentage of both bradygastria and tachygastria.
Digestive Diseases and Sciences 01/2002; 47(11):2473-2479. · 2.12 Impact Factor
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ABSTRACT: The aims of this study were to investigate the effect of duodenal distension on intestinal myoelectrical activity and to investigate whether intestinal pacing was able to reverse the effects of distension. Six female hound dogs with four pairs of electrodes on the proximal jejunum were involved in this study. The protocol consisted of 30 min of recording of jejunal myoelectrical activity as baseline and 90 min of recording during distension. Intestinal pacing was performed during the second 30 min of distension. Duodenal distension severely impaired intestinal myoelectrical activity. The percentage of normal slow waves was reduced from 90.8 8.4% at baseline to 73.8 10.2%, 57.2 11.4%, and 53.7 16.0% during the first, second and third 30 min of distension (P < 0.05,="" anova).="" the="" dominant="" power="" was="" similarly="" decreased="" and="" the="" minute-by-minute="" variation="" of="" dominant="" frequency="" was="" significantly="" increased="" after="" distension.="" intestinal="" pacing="" reversed="" distension-induced="" dysrhythmia.="" the="" percentage="" of="" normal="" slow="" waves="" during="" the="" 30="" min="" of="" distension="" with="" pacing="" was="" significantly="" higher="" than="" the="" corresponding="" 30="" min="" of="" distension="" without="" pacing="" (88.5="" ="" 6.6%="" vs="" 57.2="" ="" 11.4%,="">P < 0.03).="" it="" was="" concluded="" that="" intestinal="" pacing="" can="" normalize="" distension-induced="" dysrhythmia="" and="" has="" a="" potential="" as="" a="" future="" therapeutic="" modality="" for="" intestinal="" motor="">
Digestive Diseases and Sciences 12/1999; 45(1):129-135. · 2.12 Impact Factor
