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Biomedical subjects

S Odegaard

Publications and source records attributed to S Odegaard.

At least 19 recordsLinked to original sources
PubMed2006

A multimodal laser Doppler and endosonographic distension device for studying mechanosensation and mucosal blood flow in the oesophagus.

We describe the development of a multimodal device combining bag distension, manometry, high frequency intraluminal ultrasound, laser Doppler flowmetry and symptom registration. Bench tests showed that the different modalities did not influence each other. During bag distension we obtained high quality images of the oesophageal wall for computing biomechanical parameters, and laser Doppler signals showing variation in mucosal perfusion. We conclude that the principle of measurement is sound and that the device can provide a basis for further studies.

Animals↗
PubMed2004

Endoscopic augmentation of the lower esophageal sphincter for the treatment of gastroesophageal reflux disease: multicenter study of the Gatekeeper Reflux Repair System.

BACKGROUND AND STUDY AIMS: The safety and effectiveness of the Gatekeeper Reflux Repair System (Medtronic Europe, Tolochenaz, Switzerland) in the treatment of gastroesophageal reflux disease (GERD) was evaluated. This new, reversible treatment modality involves the endoscopic introduction of expandable polyacrylonitrile-based hydrogel prostheses into the esophageal submucosa to augment the lower esophageal sphincter (LES). PATIENTS AND METHODS: For this study, data from two prospective, nonrandomized European multicenter trials were pooled. Sixty-nine GERD patients with heartburn and regurgitation and abnormal esophageal acid exposure (24-h pH < 4.0 for > 4 % of the total time) who had responded to proton-pump inhibitor (PPI) therapy were recruited, and 68 were treated with up to six prostheses placed at the gastroesophageal junction. Patients underwent esophageal manometry, endoscopy, 24-h pH-metry, and symptom scoring at intake and 1, 3, and 6 months after the procedure. RESULTS: A total of 77 procedures were performed in 67 patients, and a total of 270 prostheses were placed (mean 4.3 per procedure). At 1 and 6 months, 80.4 % and 70.4 % of the prostheses were retained, respectively. At 6 months, 24-h pH-metry outcomes with pH < 4.0 for > 4.0 % of the time decreased from 9.1 % to 6.1 % (n = 45; P < 0.05). Median LES pressure increased significantly from 8.8 mmHg at baseline to 13.8 mmHg at 6 months (n = 42, P < 0.01). Median GERD heartburn-related quality-of-life scores improved significantly from 24.0 to 5.0 (n = 53, P < 0.01) in patients no longer receiving PPI therapy. Two serious adverse events (3.0 %) occurred. Both patients recovered uneventfully. Prostheses were endoscopically removed from one patient without any adverse events. CONCLUSIONS: The Gatekeeper Reflux Repair System is a safe endoscopic treatment modality that significantly improves GERD symptoms and has objective effects on acid reflux.

Adult↗
PubMed2002

Endoscopic ultrasonography for preoperative diagnosis and localization of insulinomas.

BACKGROUND: Endoscopic ultrasonography (EUS) is generally accepted as a sensitive method for the detection of small pancreatic tumors. We report our experience with EUS for preoperative imaging of insulinomas. METHODS: Nine patients with clinical and biochemical signs of insulinoma were examined by EUS using a 7.5/12 MHz radial-scanning ultrasound endoscope prior to surgery. EUS outcome was evaluated on the basis of surgery (open or laparoscopic) and examination of the resected specimens. RESULTS: Two EUS-negative patients appeared, by reassessment of clinical and biochemical data, not to have an insulinoma and were not operated on. EUS correctly imaged and localized five of seven insulinomas that were surgically removed. One isoechoic tumor in the pancreatic head and one pedunculated tumor connected to the caudal side of the pancreatic body were missed by EUS. EUS could demonstrate the size and shape of the imaged tumors, as well as their relationship to adjacent structures, such as the pancreatic duct, bile duct, and large vessels. CONCLUSIONS: Our experience with seven insulinomas accords with previous reports claiming EUS to be the method of choice for preoperative imaging and localization of pancreatic islet cell tumors.

Adult↗
PubMed2001

Endosonography-guided endoscopic band ligation of Dieulafoy's malformation: a case report.

Dieulafoy's vascular malformation may cause serious upper gastrointestinal hemorrhage. The mucosal lesion is usually small, and precise location of the lesion may therefore be difficult. We report a case of Dieulafoy's lesion successfully treated by endoscopic band ligation (EBL) where endoscopic ultrasonography (EUS), including Doppler examination, was applied for accurate diagnosis, guiding EBL and control of treatment.

Aged↗
PubMed2000

The development of a software program for analyzing spontaneous and externally elicited skin conductance changes in infants and adults.

OBJECTIVES: Changes in palmar and plantar skin conductance (SC) are due to outgoing bursts in the postganglionic efferent sympathetic cholinergic fibres, which responds to changes in central arousal state. The purpose of this study was designed to develop a software program for analyzing spontaneous and external elicited SC changes for infants and adults. METHODS: The program was designed to calculate the number and mean amplitude of the waves as well as the mean basal level in a given period. Different pre-set values for the minimum amplitude, maximum slope and minimum width of the spontaneous waves were used in the analysis program, and the results were compared with manually counted waves. The program was also used to perform coherent averaging of repeated elicited SC changes. For the mean elicited skin conductance responses, the latency time, response amplitude and recovery time were calculated. The habituation pattern could be calculated semi-automatically by analyzing each response. RESULTS: For SC waves, the minimum amplitude and the maximum slope should be, respectively, 0.02 microsiemens (microS) and 2 microS/s for infants and adults, and the width of the waves should be at least 1 s for adults, and unlimited for infants. The coherent average method was found to be a satisfactory method for revealing whether a subject responded to stimuli, and is recommended, especially for infants. CONCLUSIONS: Spontaneous and stimulated skin conductance are easily analyzed by this software program.

Adult↗
PubMed2000

[Intraluminal sonography in the diagnosis of gastrointestinal diseases].

Endosonography is an imaging method whereby a high frequency ultrasound probe is inserted into a body cavity with or without under endoscopic control. Examination of the gastrointestinal tract is performed using special echo-endoscopes or trans-endoscopic mini-probes. The gastrointestinal wall, mediastinum, pancreas, bile ducts, retroperitoneum, and other structures surrounding the gastrointestinal tract are target organs for endosonography. A detailed image of pathological processes can thus be obtained. The method can be used both for primary diagnosis of lesions and in follow-up of gastrointestinal diseases. It is accurate in local staging of cancer and in detecting small lesions. There are some limitations for optimal examination like stenoses or other factors prohibiting a precise positioning of the ultrasound transducer. The clinical importance of endo-sonographic examinations must be continuously evaluated on the basis of new technical modalities and changes in therapeutic procedures.

Endosonography↗
PubMed2000

Comparison of a linear miniature ultrasound probe and a radial-scanning echoendoscope in TN staging of esophageal cancer.

BACKGROUND: Endoscopic ultrasonography is a precise method for TN staging of esophageal cancer. We explored the staging properties of a linear miniprobe as compared with a radial-scanning echoendoscope. METHODS: Sixty-eight patients with esophageal cancer underwent preoperative TN staging using a 20-MHz linear miniprobe and a 7.5/12-MHz radial-scanning echoendoscope. Tumor stage was verified by surgery and/or histology. RESULTS: T and N stages were verified in 53 and 54 patients, respectively. T-staging accuracy using the echoendoscope was 70%. The high-frequency miniprobe could not differentiate between T3 and T4 tumors, but both systems had an accuracy of 87% in discriminating between T1, T2, and T3/4 stages. With traversable tumors, the accuracy of N staging was significantly better with the echoendoscope than with the miniprobe (90% vs. 48%, P = 0.008). CONCLUSIONS: The two endosonographic systems had similar accuracy for assessing transmural tumor growth, but the echoendoscope was superior in staging advanced transmural tumors and in predicting lymph node metastasis with traversable tumors.

Aged↗
PubMed1999

High-resolution endoluminal sonography in gastroenterology.

Endosonography is an imaging method where a high frequency ultrasound probe is inserted blindly or under endoscopic control into a lumen. Examination of the gastrointestinal tract is performed using dedicated echoendoscopes or transendoscopic miniprobes. The gastrointestinal wall, mediastinum, pancreas, bile ducts, retroperitoneum, and other structures surrounding the gastrointestinal tract are target organs for endosonography. A detailed image of pathological processes can thus be obtained. The method can be used both for primary diagnosis of lesions and in follow-up of gastrointestinal diseases. It is accurate in local staging of cancer and in detecting small lesions, which cannot be seen with other imaging modalities. There are some limitations for optimal examination like stenoses or other factors prohibiting a precise position of the ultrasound transducer. The clinical importance of endosonographic examinations must be continuously evaluated on the basis of new technical modalities and changes in therapeutic procedures.

Digestive System Diseases↗
PubMed1999

3D-endosonography in gastroenterology: methodology and clinical applications.

Endoluminal ultrasonography allows detailed imaging of the gastrointestinal wall and adjacent structures. Three-dimensional (3D) imaging may improve visualisation of topographic relations and the nature of pathologic lesions. The objective of this report is to summarise current status of 3D-endosonography and to discuss the possible clinical impact of this new modality. 3D ultrasonographic images are usually generated from a series of digitised two-dimensional ultrasound pictures acquired in a manner that enables registration of their relative spatial position. Such acquisition can be accomplished with different ultrasound probes, but in most cases of endosonography, a controlled pullback of radial-scanning probes has been applied. Digital ultrasound images are obtained by frame grabbing of analogue video recordings or by direct transmission from digital scanners. Dedicated software programs have been developed for 3D reconstruction and visualisation, allowing interactive display and measurements. 3D endosonography provides new possibilities for clinical imaging, but the impact on therapeutic strategies and clinical outcome has yet to be established.

Digestive System↗
PubMed1999

Hydrosonography of the small intestine: comparison with radiologic barium study.

BACKGROUND: Transabdominal ultrasonography of the small intestine is hampered by luminal gas. We have developed a new sonographic method (hydrosonography) that largely eliminates the gas problem and have compared this method with radiologic barium study. METHODS: Fifty-six patients admitted for X-ray examination of the small bowel because of abdominal pain, diarrhoea, weight loss and/or known inflammatory bowel disease were examined. To remove luminal gas before performing transabdominal ultrasonography, 21 of polyethylene glycol solution was inserted through a nasojejunal tube by means of a peristaltic pump. Wall thickness, peristalsis, luminal narrowing, prestenotic dilatation, and extraintestinal complications were recorded. RESULTS: On ultrasonography we were able to visualize the terminal part of the ileum in 98% of the patients. Perfect agreement between hydrosonography and barium studies was seen in 50 of 55 patients. However, 44 patients had normal findings on both examinations. The sensitivity and specificity of hydrosonography were 64% and 100%, respectively. The positive predictive value was 100%. For X-ray examination sensitivity and specificity were 91% and 100%, respectively. Four patients with minor mucosal abnormalities or pathologic findings in the upper part of the small intestine accounted for the relatively low overall sensitivity found for hydrosonography compared with roentgenography. However, important extraintestinal complications were disclosed by ultrasound. CONCLUSIONS: Hydrosonography of the small bowel is a new, convenient, and reliable method for examining the lower part of the small intestine. However, it cannot replace barium studies in patients with mucosal abnormalities. especially in the upper part of the small bowel.

Adolescent↗
PubMed1999

Measurements of organ volume by ultrasonography.

In a clinical context, measurements of organ volume are often performed in the diagnosis and follow-up of patients with a variety of diseases. Ultrasonography is a cheap, widely available and non-hazardous imaging modality to use for estimation of volumes, and a range of two- and three-dimensional methods have emerged to accomplish this task. This paper reviews some of the ultrasound methods available in cardiology, gastroenterology, nephrology/urology and gynaecology/obstetrics. Using two-dimensional (2D) ultrasound, the simplest method of calculating the volume of an organ is based on the multiplication of three diameters perpendicular to each other. These 2D methods are often based on geometrical assumptions which may introduce significant errors in volume estimation. Therefore, volume estimation based on three-dimensional (3D) ultrasound has been developed to increase accuracy and precision. At present, the process of making 3D images based on ultrasonography is divided into five steps: data acquisition, data digitization, data storage, data processing and data display. In conclusion, ultrasonography is a useful and reliable tool to calculate volumes of organs. In particular, 3D ultrasonography seems promising in this respect and appears to be superior to 2D ultrasonography in accuracy and precision in volume measurements.

Cardiac Volume↗
PubMed1998

In vitro evaluation of three-dimensional ultrasonography based on magnetic scanhead tracking.

The objective of this study was to evaluate the accuracy and precision of a magnetic position sensor system for acquisition of three-dimensional (3D) ultrasound images in volume estimation of phantoms in vitro. Installation of either 0.9% solution of saline at 37 degrees C or distilled water at 20 degrees C to a condom was performed. Scanning was performed either by a continuous or stepwise acquisition. This 3D ultrasound system demonstrated good correlation (r = 0.99-1.0, n = 8) between estimated (EV) and true volumes (TV). The errors were in the range 1.3%+/-0.3% (SEM) to 1.9%+/-0.6%, independent of sound velocity. Scanning through a porcine abdominal wall positioned at the fluid surface yielded a systematic underestimation of the volume: mean (EV - TV) = -7.2+/-0.8 ml. Eight repeated scans of the same volume yielded a coefficient of variation of 1.1%. Interobserver error of the tracing procedure was 2.6%+/-0.9%. This 3D ultrasound system gave high accuracy and precision in volume estimation in vitro, and yielded low interobserver error. A change in ultrasound velocity of approximately 60 m/s did not influence the accuracy significantly. Scanning through an abdominal wall underestimated volumes slightly.

Abdomen↗
PubMed1998

Dieulafoy's vascular malformation: role of endoscopic ultrasonography in therapeutic decision-making.

BACKGROUND: Dieulafoy's vascular malformation may cause severe, potentially life-threatening gastrointestinal bleeding. Endoscopic diagnosis may be difficult because of minute mucosal lesions, and additional intramural abnormalities are usually not encountered. Endoluminal high-frequency ultrasonography is a new modality for imaging intramural and perivisceral structures. METHODS: We report two cases of recurrent severe gastric bleeding in which different endosonographic modalities were used in the diagnosis of Dieulafoy's malformation, and the impact of endosonography on therapeutic strategy is discussed. In the first case a radial-scanning 7.5/12-MHz echoendoscope and a linear 20-MHz miniature probe were applied for B-mode imaging in a stable-state patient who had undergone previous endoscopic sclerotherapy, and arterial flow signals from the small intramural lesion were recorded using a 10-MHz transendoscopic pulsed Doppler probe. In the other case urgent endosonography was performed shortly after a bleeding episode, disclosing an aberrant large-calibre artery entering the gastric wall with a long submucosal branch. RESULTS: Both patients were successfully operated on with a transabdominal approach. CONCLUSION: Endosonography is a quick and safe diagnostic method and should be considered when vascular malformations are suspected as the cause of gastric bleeding.

Adult↗
PubMed1998

Flow across the human pylorus soon after ingestion of food, studied with duplex sonography. Effect of glyceryl trinitrate.

BACKGROUND: By means of duplex sonography, gastric emptying can be related to antral motor activity. The aim of this study was to examine gastric emptying in relation to antral contractions during and immediately after ingestion of a liquid meal in healthy subjects and to study the effect of glyceryl trinitrate (GTN) on this early phase of gastric emptying. METHODS: Ten healthy, non-smoking men (median age, 36 years; range, 29-41 years) were studied twice on separate days, once without drug administration and once after taking a 0.5-mg sublingual GTN tablet 3 min before ingesting 500 ml of a meat soup (20 kcal; Toro). The subjects were investigated during 3 min of fasting, during 3 min of drinking the soup, and during the first 10 min postprandially. RESULTS: Transpyloric forward flow commenced on average 80 sec and 95 sec after the start of drinking the soup without and with GTN, respectively (P = NS). Non-contractile, pulsatile transpyloric flow (that is, pendulating, transpyloric flow not associated with antral contractions) occurred during episodes of concurrent relaxation of the terminal antrum, the pylorus, and the duodenal bulb. This type of flow occurred mainly just before the start of contractile, pulsatile transpyloric flow (associated with propulsive antral contractions). Initial non-contractile, pulsatile transpyloric flow before commencement of contractile, pulsatile transpyloric flow lasted longer with GTN (188 sec) than without GTN (25 sec) (P < 0.05). Consequently, contractile, pulsatile transpyloric flow commenced later with GTN (302 sec) than without (102 sec) (P < 0.05). CONCLUSIONS: Non-contractile transpyloric flow seems to be a physiologic phenomenon during the early phase of gastric emptying. GTN prolongs the initial phase of non-contractile, and delays the onset of contractile, pulsatile transpyloric flow.

Adult↗