Biomedical subjects

T Hausken

Publications and source records attributed to T Hausken.

At least 37 records · Page 2Linked to original sources

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

The significance of personality in pain from gallbladder stones.

BACKGROUND: The aim of the study was to investigate the association between personality factors related to coping styles and reported pain due to gallstones. METHODS: Personality trait measures were completed by 28 consecutive gallstone patients to provide estimates of positive coping resources (Life Regard Index, Sense of Coherence Scale, Sense of Humor Questionnaire) and negative coping resources (Eysenck Personality Questionnaire on Neuroticism, Tension, and Effort Stress Inventory). An overall index of gallstone-related complaints (pain) over the past 7 days/6 months was also obtained. Ultrasonography confirmed the gallstone condition. Multiple regression analyses tested the hypothesis that pain would be moderated by positive coping resources and mediated by negative coping resources. RESULTS: Reported pain was less severe with positive coping resources (39% of pain variance explained) and more severe with negative coping resources (45% of pain variance explained). CONCLUSION: The results confirm that mental coping resources have a significant role in pain differences among gallstone patients.

Adaptation, Psychological↗

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

Spiramycin is comparable to oxytetracycline in eradicating H. pylori when given with ranitidine bismuth citrate and metronidazole.

BACKGROUND: We have consistently achieved about 90% eradication of H. pylori with liquid bismuth, metronidazole and oxytetracycline. AIM: To test eradication and adverse events of ranitidine bismuth citrate (RBC) when given with metronidazole and either oxytetracycline or spiramycin. METHODS: One hundred and eighty-three patients were randomized to one of four 10-day regimens: RBC400OM: RBC 400 mg b.d., oxytetracycline 500 mg q.d.s.; RBC400SM: RBC 400 mg b.d., spiramycin 1 g q.d.s.; RBC200OM: RBC 200 mg q.d.s., oxytetracycline 500 mg q.d.s.; RBC200SM: RBC 200 mg q.d.s., spiramycin 1 g q.d.s. Additionally, all patients received metronidazole 400 mg q.d.s. A 14C-urea breath test was performed at 8 weeks. RESULTS: Intention-to-treat eradication rates were 94%, 91%, 94% and 89% with RBC400OM, RBC400SM, RBC200OM and RBC200SM, respectively (P = 0.81). Eradication was significantly higher in ulcer patients (97%) than in those with diagnoses other than ulcer (86%) (P = 0.009). There was a strong tendency to better eradication among those who had never smoked (100%) compared with ex-smokers (93%) and smokers (89%) (P = 0.06). Fifty-three per cent experienced at least one moderate or severe adverse event, and women had more adverse events than men (P = 0.0002). CONCLUSIONS: All four regimens had comparable efficacy and adverse events. Eradication was significantly better in ulcer patients but there was a trend to better eradication in those who smoked less, used less alcohol and exercised more. Adverse events were frequent, perhaps because of the large dose of metronidazole used, but few patients stopped treatment.

Adult↗

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

Estimation of the human liver volume and configuration using three-dimensional ultrasonography: effect of a high-caloric liquid meal.

The aim of this study was to investigate whether or not a magnetic position sensing system for free-hand acquisition of 3-D ultrasound images could be used to estimate liver volumes, and to study the effect of a high-caloric meal on these volumes in healthy subjects. In vitro accuracy was evaluated by scanning porcine and rabbit livers. Ten healthy subjects were examined fasting and 30 min after ingesting a high-caloric liquid meal. Portal and hepatic vein blood flow were measured by 2-D duplex sonography. The 3-D system yielded a strong correlation (r = 0.99) between true and estimated volumes in vitro. No significant increase in liver volume in response to the meal was seen. However, portal and hepatic vein flow volume increased significantly. Experience in human subjects suggests that a complete 3-D study of liver volumes can be obtained from multiple acoustic windows. In healthy subjects, no significant increase in liver volume was seen in response to ingestion of a high-caloric liquid meal.

Adult↗

PubMed1998

Effect of mental stress and cisapride on autonomic nerve functions in functional dyspepsia.

BACKGROUND: Disordered autonomic nerve function is frequently present in patients with functional dyspepsia (FD). In this study we investigated whether the prokinetic cisapride, which acts via acetylcholine receptors, and stress may modulate these abnormalities. METHODS: Nineteen patients (6 men, 13 women) with FD and 10 healthy subjects (3 men, 7 women) were studied after 3 days' treatment with 10 mg cisapride three times daily and placebo in a crossover design. Mental stress was induced with a videogame. Sympathetic and vagal nerve functions were assessed noninvasively by skin conductance and respiratory sinus arrhythmia, respectively. RESULTS: Vagal tone was significantly lower in FD patients than in controls both before and after mental stress (P < 0.001). Sympathetic tone was higher in patients with FD than in controls (P < 0.03). Generally, stress scores were increased by mental stress in both groups (P < 0.001). In FD patients, but not in controls, cisapride significantly increased the sympathetic tone both before (P < 0.05) and after stress (P < 0.05). CONCLUSIONS: Patients with FD have lower vagal tone and higher sympathetic tone than healthy controls. Treatment with cisapride increased sympathetic tone in the patient group but had no effect on vagal tone.

Adult↗

PubMed1998

Gastric meal accommodation studied by ultrasound in diabetes. Relation to vagal tone.

BACKGROUND: Disturbed gastric meal accommodation may cause abdominal symptoms in patients with functional dyspepsia and diabetes mellitus who have poor vagal control of gastric motility. In the present study we aimed to explore the relation between gastric meal accommodation and vagal tone in diabetic patients with vagal neuropathy. METHODS: Twenty patients with diabetes (DM) (insulin-dependent type; 10 men and 10 women, aged 35.3 +/- 7.6 years) and 20 healthy controls (HC) (10 men and 10 women; aged 34.7 +/- 10.7 years) were studied. Proximal gastric size was assessed with ultrasound in a sagittal area and a frontal diameter. Distal gastric (antrum) size was assessed in a sagittal area. Vagal tone was assessed non-invasively by recording of respiratory sinus arrhythmia (RSA) in beats per minute. RESULTS: Proximal sagittal area was significantly (P = 0.03) smaller in DM (18.5 +/- 5.5 cm2) than in HC (22.2 +/- 4.6 cm2). Proximal frontal diameter did not differ significantly (P = 0.60) between DM and HC (5.9 +/- 1.1 cm versus 5.7 +/- 0.8 cm). Antral area, too, did not differ significantly (P = 0.59) between DM and HC (14.5 +/- 4.1 cm2 versus 13.6 +/- 5.8 cm2). Proximal/distal meal distribution ratio, defined as proximal sagittal area/distal sagittal area, was significantly (P = 0.05) smaller in DM (6.8 +/- 0.6) than in HC (9.9 +/- 5.5). Vagal tone was significantly (P = 0.03) lower in DM (4.5 +/- 1.9 beats/min) than in HC (6.3 +/- 2.7 beats/min). Vagal tone tended (r = 0.33, P = 0.06) to correlate with proximal sagittal area in DM and HC pooled. Vagal tone correlated (r = 0.34, P = 0.05) with proximal frontal diameter in DM and HC pooled. A significant negative correlation (r = -0.39, P = 0.03) was observed between vagal tone and antral area in DM and HC pooled. CONCLUSIONS: Patients with diabetes and low vagal tone have an impaired postprandial gastric meal distribution characterized by a small proximal stomach and a small proximal/distal meal distribution ratio.

Adult↗

PubMed1998

Timing of postprandial dyspeptic symptoms and transpyloric passage of gastric contents.

BACKGROUND: Patients with functional dyspepsia often experience early satiety and discomfort after a meal. The role of early gastric emptying in symptom generation is not known. Our aim was to relate timing of symptoms and early postprandial emptying in functional dyspepsia. METHODS: Twelve patients with functional dyspepsia were investigated during 3 min of fasting, during 3 min of ingesting 500 ml of a meat soup, and during the first 10 min postprandially by means of duplex sonography. RESULTS: Gastric emptying commenced on average 52 sec after the start of ingestion. Transpyloric movements of gastric contents unrelated to peristalsis (that is, alternating transpyloric emptying and reflux within a common chamber created by the terminal antrum, the pylorus, and the duodenal bulb) appeared before peristaltic-related emptying, which commenced after on average 116 sec. In all patients epigastric, meal-related discomfort was experienced after the commencement of transpyloric emptying, on average after 143 sec. A negative correlation was found between intensity of fullness and duration of presymptomatic transpyloric movements of gastric contents (that is, the duodenal 'tasting' period). CONCLUSIONS: The early occurrence of meal-related symptoms suggests that gastric distension is the main factor in symptom generation. However, the onset of symptoms after the commencement of gastric emptying suggests that intestinal tasting receptors are involved in symptom generation. The inverse relationship between the duration of the tasting period and symptom intensity suggests that the time allowed for duodenal tasting might be too short in patients with FD.

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↗

PubMed1998

Imaging studies in dyspepsia.

Patients with functional dyspepsia have discomfort centred in the upper abdomen in the absence of oesophagitis, ulcer, cancer or other pathology which could have explained the dyspepsia. It is generally accepted that neither endoscopy, nor other imaging modalities give any positive findings supporting the diagnosis. However, recent investigations have shown that both endoscopic and ultrasonographic imaging show changes: erosive prepyloric changes (EPC) and accommodation abnormalities, respectively, in a high percentage of the patients. The diagnostic sensitivity and specificity of the changes are not yet known, but the fact that they are also seen in several other conditions characterised by dyspepsia, for instance in gallstone disease, may simply indicate that they are linked to epigastric discomfort in general, and not to a specific dyspeptic condition. Ultrasonographic imaging is a non-invasive, widely available, convenient, and reliable method for evaluation of gastric emptying, gastric motility, transpyloric flow and accommodation disturbances, which may play a crucial role in the pathogenesis of dyspepsia.

Dyspepsia↗

PubMed1998

Gastric meal accommodation and symptoms in diabetes. A placebo-controlled study of glyceryl trinitrate.

OBJECTIVE: To study mechanisms behind postprandial symptoms in patients with diabetes mellitus and the effect of nitric oxide (NO) on gastric accommodation and symptoms in these patients. DESIGN: A double-blind, placebo-controlled, randomized trial was designed in 20 patients with type 1 diabetes (10 male and 10 female, aged 35.3 +/- 7.6 years). METHODS: 0.5 mg sublingual glyceryl trinitrate (GTN), a donor of exogenous NO, or placebo was administered 5 min prior to a 500 ml soup meal. Gastric accommodation of the meal was assessed by abdominal ultrasound. Accommodation in proximal stomach was visualized in a sagittal area (Psa) and a frontal diameter (Pfd) and accommodation in distal stomach was visualized in a sagittal area of the antrum (Asa). Symptoms were assessed using visual analogue scales. RESULTS: Psa correlated significantly (r = 0.57, P = 0.015) with perception of fullness 5 min after the meal, whereas Pfd correlated significantly (r = 0.67, P = 0.004) with nausea at 15 and at 25 min after the meal. Asa correlated (r = 0.50, P = 0.05) with pain at 5 min, 10 min (r = 0.50, P = 0.05) and 25 min (r = 0.68, P = 0.007). GTN had no significant effect on Psa or Pfd, but reduced significantly (P = 0.05) Asa (1 3.5 +/- 4.5 cm2 with GTN vs 16.1 +/- 4.3 cm2 with placebo). GTN increased significantly (P = 0.04) the intragastric proximal/distal meal distribution ratio (proximal/distal sagittal area), but had no significant effect on symptom scores. CONCLUSION: In patients with diabetes, a large proximal stomach is associated with perception of fullness and a large antrum is associated with perception of pain after a meal. Sublingual administration of GTN prior to the meal decreases the antral area and improves the intragastric meal distribution, but fails to improve symptoms.

Cross-Over Studies↗

PubMed1997

Effect of glyceryl trinitrate on gastric accommodation and symptoms in functional dyspepsia.

The purpose of this study was to investigate whether sublingual glyceryl trinitrate influences the size of the proximal stomach and postprandial symptoms in patients with functional dyspepsia. Twenty patients with functional dyspepsia were included in a double-blind, placebo-controlled crossover study with sublingual glyceryl trinitrate. All patients were scanned twice on consecutive days, receiving either placebo or 0.5 mg glyceryl trinitrate randomly 5 min prior to ingestion of 500 ml meat soup. Total symptoms, pain, nausea, and bloating were scored on a visual analog scale before and after the meal. Standardized ultrasonograms were obtained 1, 10, and 20 min postprandially of the proximal and distal stomach. The proximal stomach was larger in the sagittal section at 1 min postcibally (26.5 +/- 3.9 vs 24.8 +/- 4.9 cm2, P = 0.036) and 10 min postprandially (22.0 +/- 5.1 vs 19.8 +/- 5.3 cm2, P = 0.009) after administration of glyceryl trinitrate compared with placebo, whereas a tendency was observed after 20 min (18.7 +/- 5.5 vs 17.3 +/- 5.7 cm2, P = 0.076). The corresponding changes in the frontal diameters were 8.3 +/- 1.1 vs 7.8 +/- 1.2 cm (P = 0.067) after 1 min, 7.2 +/- 0.9 vs 6.4 +/- 0.8 cm (P = 0.001) after 10 min, and 6.3 +/- 1.1 vs 5.6 +/- 1.2 cm (P = 0.016) after 20 min. The area of the distal stomach was not different (P > 0.31) in the two groups. After administration of glyceryl trinitrate, the patients reported less pain (P = 0.048) and nausea (P = 0.023) 5 min postprandially, but this effect was reduced 15 min later. Total symptom score was improved by glyceryl trinitrate treatment (P < 0.042). Sublingual glyceryl trinitrate improves accommodation of the proximal stomach to a meal and reduces postprandial symptoms in a group of patients with functional dyspepsia.

Administration, Sublingual↗

PubMed1997

Common pathogenetic mechanisms in symptomatic, uncomplicated gallstone disease and functional dyspepsia: volume measurement of gallbladder and antrum using three-dimensional ultrasonography.

Following cholecystectomy for uncomplicated gallstone disease (GS) some patients experience persistent symptoms suggesting an underlying functional disorder. To study this phenomenon, we have compared symptomatic GS with functional dyspepsia (FD) patients and healthy individuals (C) with respect to putative pathogenetic mechanisms. Gallbladder and gastric antrum volumes were estimated with three-dimensional (3D) ultrasonography before and 10 min after ingestion of 500 ml meat soup in 18 patients with GS. Volume estimation was performed digitally after interactive manual tracing and organ reconstruction in three dimensions. Respiratory sinus arrhythmia (RSA) was calculated to index vagal tone. Abdominal symptoms were assessed by interview. The results were compared to previously published data in patients with FD and C investigated with the exact same methods. No significant differences were found between groups with respect to fasting gallbladder or gallbladder emptying. Antral volumes both fasting (P < 0.05) and postprandially (P < 0.01) were larger in GS and FD than in C. The soup meal induced dyspeptic symptoms in 2/18 (11%) of C, 12/18 (67%) of GS and 15/17 (88%) of FD patients (P < 0.001). Compared with C, both GS and FD patients had significantly decreased vagal tone (P < 0.001). There was no significant difference between GS and FD patients with respect to antral volume, vagal tone, or symptoms. We concluded that both gallstone and functional dyspepsia patients are characterized by dyspeptic symptoms in response to ingestion of 500 ml of meat soup, a wide gastric antrum, low vagal tone, but normal gallbladder size and emptying. Thus, patients with symptomatic, uncomplicated gallstone disease and functional dyspepsia seem to have common pathogenetic mechanisms.

Adolescent↗

PubMed1997

Lower postprandial gastric volume response in diabetic patients with vagal neuropathy.

UNLABELLED: Poor relaxation in the stomach after a meal may contribute to disturbed gastric emptying and abdominal discomfort in patients with diabetes mellitus. In this study we aimed to compare barostat-recorded postprandial volume responses in these patients to those in healthy controls, and to study the relationship between the proximal volume responses, antral filling and vagal neuropathy. We compared 14 consecutively recruited patients with type 1 diabetes mellitus (DM) to 18 healthy controls (HC) with respect to meal-induced gastric volume response assessed by a barostat, antral area recorded by ultrasound, and vagal tone assessed by respiratory sinus arrhythmia (RSA). Meal-induced volume response of the proximal stomach (area under time-volume curve 0-30 min) was significantly (P = 0.04) lower in DM than in HC, 49.4 min.mL +/- 60.7 vs. 114.9 min.mL +/- 100.8. Antral area was significantly larger in DM than in HC, both fasting (4.3 cm2 +/- 1.9 vs. 3.0 cm2 +/- 0.9) and 10 min after ingestion of meat soup (11.8 cm2 +/- 3.4 vs. 8.8 cm2 +/- 2.9), P = 0.03 and P = 0.02, respectively. Vagal tone was significantly (P = 0.01) lower in DM than in HC. 3.7 beats min-1 +/- 2.3 vs. 6.1 beats min-1 +/- 2.2. No significant correlation was observed between the proximal volume responses and antral widening. Maximal gastric volume response correlated significantly with vagal tone (r = 0.77, P = 0.002). CONCLUSIONS: patients with diabetes mellitus type 1 have impaired meal-induced volume response, possibly as a consequence of reduced vagal tone.

Adult↗

PubMed1996

[High frequency ultrasonography of the gastrointestinal wall].

If an ultrasound probe comes close to the area of interest, high ultrasound frequencies can be applied. Endoscopic ultrasonography is performed by means of echoendoscopes or miniature probes using ultrasound frequencies between 7 and 30 MHz. A high frequency ultrasound image of the normal gastrointestinal wall usually shows five layers corresponding closely to the histological layers of the wall. Corrections have to be made, however, for interface echoes between layers with different acoustic impedances. We describe studies performed with the aim of correlating ultrasound images of the normal and diseased gastrointestinal wall with the histology. Ultrasound images of the normal gastrointestinal wall and pathological changes like ischemia, ulcers, tumours and inflammation are presented.

Gastric Mucosa↗