L. B. Nesje

Prophylaxis of postoperative relapse in Crohn's disease with mesalamine: European cooperative Crohn's disease study VI

BACKGROUND & AIMS This study investigated if long-term treatment with high-dose mesalamine reduces the risk of clinical relapse of Crohns disease after surgical resection. METHODS In a prospective, randomized, double-blind, multicenter study, 4 g of mesalamine (Pentasa; Ferring A/S, Vanlose, Denmark) daily was compared with placebo in 318 patients. Treatment was started within 10 days after resective surgery and continued for 18 months. Primary outcome parameter was clinical relapse as defined by an increase in Crohns Disease Activity Index, reoperation, septic complication, or newly developed fistula. Risk factors for recurrence were prospectively defined to be analyzed in a stepwise proportional hazards model. RESULTS Cumulative relapse rates (+/-SE) after 18 months were 24.5% +/- 3.6% and 31.4% +/- 3.7% in the mesalamine (n = 152) and placebo (n = 166) groups, respectively (P = 0.10, log-rank test, 1-sided). Retrospective analysis showed a significantly reduced relapse rate with mesalamine only in a subgroup of patients with isolated small bowel disease (n = 124; 21.8% +/- 5.6% vs. 39.7% +/- 6.1%; P = 0.02, log-rank test). Probability of relapse was predominantly influenced by the duration of disease (P = 0.0006) and steroid intake before surgery (additional risk, P = 0.0003). CONCLUSIONS Eighteen months of mesalamine, 4 g daily, did not significantly affect the postoperative course of Crohns disease. Some relapse-preventing effect was found in patients with isolated small bowel disease.

Freehand Real-Time Elastography: Impact of Scanning Parameters on Image Quality and In Vitro Intra- and Interobserver Validations

Real-time elastography is a method for visualization of the elastic properties of soft tissue and may potentially enable differentiation between malignant and benign pathologic lesions. Our aim was to validate the method on a tissue-mimicking (TM) phantom and to evaluate the influence of different scanning parameters and investigator variability. A TM-phantom containing eight spherical inclusions with known storage modulus was examined using two different transducers on an ultrasound (US) scanner equipped with software for real-time elasticity imaging. The ultrasound transducers were moved vertically in a repetitive manner to induce strain. Two investigators performed series of standardized elastography scans applying a 0-4 categorical quality scale to evaluate the influence of seven parameters: dynamic range of elasticity, region-of-interest, frequency of transducer movement, rejection of elastogram noise, frame rate, persistence and smoothing. Subsequently, repeated examinations of four selected inclusions were performed using a visual analog scale (VAS) where investigators marked a 100 mm horizontal line representing the span in image quality based on experience from the first examination. The hardest and softest inclusions were imaged more clearly than the inclusions with elasticity more similar to the background material. Intraobserver agreement on elastogram quality was good (kappa: 0.67 - 0.75) and interobserver agreement average (kappa: 0.55 - 0.56) when using the categorical scale. The subsequent VAS evaluation gave intraclass-correlation coefficients for the two observers of 0.98 and 0.93, respectively, and an interclass-correlation coefficient of 0.93. Real-time elastography adequately visualized isoechoic inclusions with different elastic properties in a TM-phantom with acceptable intra- and interobserver agreement. Dynamic range of elasticity was the parameter with most impact on the elastographic visualization of inclusions.

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.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.

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.

Ultrasonography of the Human Stomach

UNLABELLED Improved technology and new systems have expanded the possibilities of using ultrasound in clinical gastroenterology. METHODS Conventional real-time ultrasound was applied to the stomach in order to study motor activity and accommodation to meals. The antrum was imaged by various modalities of two- and three-dimensional ultrasonography, while duplex sonography was used for studying transpyloric flow. Miniature ultrasound probes and echo-endoscopes were employed for endoscopic ultrasound RESULTS The examinations provided new information about contractions, distension, co-ordination of movements, and flow. Patients with functional dyspepsia were characterized by rapid emptying of the proximal stomach, wide gastric antrum, early commencement of transpyloric flow, and epigastric discomfort following ingestion of a meat soup. Endoscopic ultrasonography exposed detailed images of the gastric wall and adjacent structures of great importance in clinical decision-making. CONCLUSIONS The new ultrasound methods have improved our diagnostic capabilities and opened new promising possibilities for further research in the field of motility.

Subepithelial masses of the gastrointestinal tract evaluated by endoscopic ultrasonography.

OBJECTIVES To diagnose and characterize subepithelial lesions of the gastrointestinal (GI) tract using endoscopic ultrasonography (EUS) and search for markers of malignancy in stromal cell tumors. METHODS Fifty-four patients with suspected subepithelial lesions at endoscopy were examined using miniature ultrasound probes, integrated ultrasound endoscopes, or both. Surgical treatment was considered if a solid lesion had a maximum diameter of at least 3 cm, mixed echogenicity, or an ill-defined or irregular border. RESULTS EUS disclosed 37 solid lesions and ten fluid-filled structures. In seven patients, including two with protrusion from a normal spleen, no pathology could be demonstrated. Thirteen patients were operated and 41 were observed clinically with (n = 9) or without EUS (n = 32) for a median follow-up period of 36 months. Twenty-three patients had an intramural stromal cell tumor. None of these were malignant, but increased mitotic activity was found in two medium-sized resected tumors with mixed echogenicity and bleeding lesions of the endoluminal surface. CONCLUSION EUS can detect and characterize subepithelial masses in the GI tract. Pathologic lesions of the overlying mucosa may indicate malignant development in stromal cell tumors, but valid markers of malignant potential are still lacking.

Crohn's disease: Comparison of in vitro ultrasonographic images and histology

Objective. To examine some typical histological findings in Crohns disease using high-frequency ultrasound and to define the echo properties of these findings. Material and methods. Bowel resection specimens from 14 patients operated on for Crohns disease were examined with a 10 MHz linear array ultrasound transducer in a saline reservoir. Needles were placed in the specimen corresponding to the ultrasound plane. After formalin fixation, histological sections were taken according to these markings. Fifty-eight ultrasonographic images with 123 regions of interest were compared with corresponding histology. Results. A thickened muscularis mucosae (>0.3 mm) was found in 48 of 69 regions of interest on histology. Submucosa with slight to moderate fibrosis was imaged as an echo-rich layer with sporadic, echo-poor elements (36/56), while severe fibrosis was seen as an echo-rich layer with diffuse, echo-poor elements (40/55). Muscularis propria with slight to moderate fibrosis was seen as an echo-poor layer with sporadic, echo-rich elements (49/66) while severe fibrosis was seen as an echo-poor layer with diffuse, echo-rich elements (17/22). Crohns rosary was seen as echo-poor extensions of the 4th echo layer (31/50). Conclusions. Typical histological findings in Crohns disease such as a thickened muscularis mucosae and Crohns rosary can be imaged with high-frequency ultrasound in vitro. Fibrosis in the submucosa and muscularis propria is associated with decreasing and increasing echogenicity, respectively.

Dieulafoy's Vascular Malformation: Role of Endoscopic Ultrasonography in Therapeutic Decision-Making

BACKGROUND Dieulafoys 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 Dieulafoys 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.

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

Abstract  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.

Three-dimensional intraluminal sonography in the evaluation of gastrointestinal diseases

Intraluminal ultrasonography (US) of the gastrointestinal (GI) tract allows detailed imaging of the GI wall and its immediate surroundings. Several endosonographic (ES) systems are available either as echoendoscopes, where an ultrasound transducer is built into the tip of an endoscope, or as miniature probes, which can be passed through the accessory channel of conventional endoscopes. Threedimensional transabdominal ultrasonography has been used to estimate emptying rates of the stomach and gallbladder and to study gastrointestinal organs and lesions [1-9]. Recently, three-dimensional endosonography (3DES) has been introduced as a new ES modality in the evaluation of GI diseases [10-17]. Reconstructed 3D images are assumed to be easier to understand than the corresponding series of two-dimensional (2D) images; hence, the spatial recognition of GI anatomy and pathological lesions can be facilitated by this method. Three-dimensional visualization techniques are rapidly evolving for most imaging modalities. Three-dimensional ES is still a developing and time-consuming technique that includes five major steps: data acquisition, digitization, storage, processing, and display. However, the goal of the ongoing methodological development is to achieve real-time systems that allow online spatial reconstruction of acquired ultrasonograms. To be processed by a computer, conversion of ultrasonographic data into a digital format is necessary. Conversion may be done by video frame grabbing, which may, however, impair the image resolution. The optimal acquisition quality is achieved when the raw US data are digitized directly at the transducer level, thus maintaining the original resolution. After data capture and digitization, the image data can be stored temporarily until computer processing takes place. Three-dimensional US images must be displayed in a comprehensive way. Two-dimensional display of orthogonal or arbitrarily angled sections through the scan-converted volumes