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## 321 ULTRASOUND ASSISTED PERCUTANEOUS LIVER BIOPSY

A. Jayaprakash1, M. Callaway2, J. Virjee2, R.E. Barry1. 1Department of Gastroenterology and 2Radiology, Bristol Royal Infirmary, Bristol, UK

Objective: To identify whether US makes a difference to the site of liver biopsy compared to the traditional blind method.

Methods: Design: Prospective study. Setting: University teaching Hospital. All patients who underwent liver biopsy between Nov 2000 and Aug 2001 had the proposed biopsy site localised by traditional percussion by a trainee or consultant. The actual biopsy site was then determined using US by a single operator (trainee) in the same sitting. Then the biopsy was performed using the most appropriate site, away from potential structures that can be encountered in the biopsy needle path.

Results: All patients preferred to have US guided biopsy when they were offered a choice between blind and US guided biopsy. 56 Liver biopsies were performed. Of these, 50% (28) of the patients needed a change in biopsy site after US examination. The changes in the biopsy site were, change in the angle of the needle in 4 patients, in the same space but more anterior or posterior placement in 9 patients, one or more spaces below in 8 patients and in 7 patients biopsy site moved up by one space. The reasons for the change in site were, proximity to gall bladder (12 patients), lung (6), bile duct (5), kidney (1) and a vessel (1) and the better depth of the biopsy needle (5). There was no difference between consultant and trainee (p=0.77) in the frequency with which the proposed biopsy site was changed after US examination.

Conclusions: US did make a difference in the liver biopsy site in 50% of patients. There is no difference in the blind localisation site by consultant and trainee. Adoption of US guided liver biopsy is preferable provided the resource is available.

## 322 OBSERVER VARIATION IN STAGING RECTAL CANCERS BY ENDORECTAL ULTRASOUND

P.J. Arumugam, B. Patel, A. Roberts, A. Watkins, P. Basnyat, R. Morgan, N.D. Carr, J. Beynon (introduced by Dr Shah). Departments of Colorectal Surgery and Radiology, Singleton Hospital, Swansea, Wales, UK

Aim: To determine the accuracy of endorectal ultrasound and the intra and inter observer variation in the preoperative staging of rectal cancers between the specialities.

Methods: Rectal cancer patients undergoing primary surgery were included. Histopathology was used as the gold standard. The observers included two radiologists and two colorectal consultant surgeons.

Results: Endorectal ultrasound: Postoperatively looking at hard copies surgeon 1 (S 1), T' staged 16 out of 31 cancers accurately Kendall's tau (K t 0.46) and surgeon 2 (S 2), T' staged 7 out of 31 accurately (K t 0.34). Radiologist 1 (R 1), T' staged 14 out of 31 cancers accurately (K t 0.242) and radiologist 2 (R 2), T' staged 15 out of 31 cancers (K t 0.302). (R 1) had an excellent intraobserver agreement in T' staging (K t 0.792) and (R 2) a perfect intraobserver agreement (K t 1) compared to their original preoperative staging. Between R1 and R 2 interobserver agreement was good (K t 0.681). Between (S1) and (S 2) interobserver agreement was moderate (K t 0.46) and between R1 and S 1 agreement was good (K t 0.53). The intra and interobserver agreement for nodal N' staging were very similar to the `T' staging.

Conclusion: Endorectal ultrasound has been shown previously to be the most accurate method of staging to assess local invasion in rectal cancer. This study does not confirm that observation and it may be due to hard copies used rather than real time images and inflammation around the tumour leading to incorrect staging. However we found that the overall intra and inter observer agreement using hard copies is good.

## 323 INITIAL EXPERIENCE WITH ENTERAL STENTS FOR PALLIATION OF NON-OESOPHAGEAL PRIMARY MALIGNANT OBSTRUCTION OF THE UPPER GASTROINTESTINAL TRACT

S. Moreea, G. Naylor, C.L. Kay1, C.G. Beckett. Department of Gastroenterology and 1Radiology, Bradford Royal Infirmary, Duckworth Lane Bradford BD9 6RJ, UK

Background: Expandable metal stents are increasingly used in the palliation of malignant obstruction in the gastrointestinal (GI) tract. It provides a non-surgical means of relieving obstruction in patients at high risk from surgical intervention.

Aims: To evaluate the technical success rate, complication rate and the effectiveness of enteral stents in providing symptomatic relief of upper GI obstruction during their initial use in our hospital.

Methods: The notes of all patients who had an enteral stent placed for malignant obstruction of a non-oesophageal primary site in the upper GI tract were reviewed.

Results: Enteral stent placement was attempted in 14 patients (11 male, 3 female, age 49–87, mean 70 years). 11/14 employed a combined endoscopic & radiological approach, 3 radiological alone, with 1 failure in each group. There were 5 cases of obstruction due to tumour recurrence following surgery, 5 cases of unresectable gastric carcinoma, 3 cases of unresectable pancreatic carcinoma and 1 ampullary carcinoma. Flamingo stents (Boston Scientific Int.) were used in 2 cases following Ivor Lewis oesophagogastrectomy. Enteral Wall stents were used in the remainder of cases (Boston Scientific Int.). The technical success rate was 12/14 (86%). 1 patient required 2 stents and one 3 stents. 3 patients required metal biliary stents. There were no immediate complications. There were no cases of stent migration. 1 patient died unexpectedly within 24 hours of stent insertion. Symptom relief was obtained in the remaining 11 patients. 3 patients survived one week, all succumbing as inpatients to metastatic disease. 8 patients were discharged from hospital. 6 patients survived between 11 and 135 days (mean 35 days) and 2 are still alive at 2 and 4 months. The 2 patients who could not be stented survived 11 and 21 days.

Conclusions: This series demonstrates the effectiveness of enteral stenting in the palliation of malignant obstruction of the upper GI tract, enabling many patients to be supported out of hospital. Improved patient selection will optimise palliation. The preferred method of placement was a combined endoscopic/radiological approach.

## 324 THE CLINICAL USEFULNESS OF LIVER TRANSIT TIME STUDY WITH CONTRAST ENHANCED ULTRASONOGRAPHY IN THE DIAGNOSIS OF CIRRHOSIS

C.W.Y. Lai, D. Cochlin, A.B. Hawthorne. Department of Radiology and Gastroenterology, University Hospital of Wales, Heath Park, Cardiff, UK

Background: The transit time of an ultrasound contrast agent, Levovist (Schering AG, Berlin, Germany) between the antecubital and hepatic veins has been shown to be shorter in patients with cirrhosis compared to those without cirrhosis. (Albrecht T et al. Lancet 1999; 353: 1579–83)

Aim: To assess the clinical usefulness of this technique in distinguishing between hepatitis and cirrhosis.

Methods: We studied 8 subjects with biopsy proven cirrhosis (cirrhotic group), 8 with biopsy proven non-cirrhotic diffuse liver disease (hepatitic group) and 7 healthy controls. A standard abdominal ultrasound study by a single radiologist (DC) was performed, looking at the hepatic echodensity, echotexture, spleen size, portal venous diameter and blood flow. A bolus injection of 2.5g Levovist at a concentration of 300mg/ml was given in an antecubital vein. The transit time was defined as the time interval between the start of the injection of Levovist and a 10% rise in the signal intensity from baseline in a pre-selected hepatic vein. The peak and gradient of the upslope of the signal intensity curves were recorded.

Results: There was no difference in the echotexture and echodensity of the liver, the portal venous diameter and blood flow pattern between the 3 groups. 4/8 cirrhotic subjects had splenomegaly and none in the other 2 groups (p=0.011). The cirrhotic and hepatitic groups had shorter transit time (mean=26.9 & 26.3 seconds, respectively) than controls (mean=36.7 seconds, p=0.012 & 0.006 respectively). There was no difference in transit time between the cirrhotic and hepatitic groups. The cirrhotic group had a shorter peak time (mean=34.8 seconds) than control (mean= 52 seconds, p=0.004) and hepatitic group (mean=48.4 seconds, p=0.034). However, there was overlap in these parameters between all 3 groups.

Conclusions: The transit time of Levovist was shorter in the cirrhotic and hepatitic subjects than normal controls. The cirrhotic group had an earlier peak time than control and hepatitic group. However, the presence of some overlap in these parameters between the 3 groups limited the clinical usefulness of this technique.

## 325 USE OF A NOVEL TECHNIQUE FOR AUTOMATED POLYP DETECTION IN CT COLONOGRAPHY

R.J.T. Sadleir1, A.C. Moss2, P.F. Whelan1, H.M. Fenlon3, P. MacMathuna2 (introduced by J.R. Lennon2). 1Vision Systems Laboratory, School of Electronic Engineering, Dublin City University, Dublin 9, Ireland; 2Gastrointestinal Unit and 3Department of Radiology, Mater Misericordiae Hospital, Eccles Street, Dublin 7, Ireland

Purpose: CT Colonography (CTC), also known as “Virtual Colonoscopy” is an emerging colon-imaging technique. Conventional analysis of raw CTC datasets by radiologists is time-consuming. We present initial results of a study using novel image analysis software to enhance current techniques and “flag” potential colorectal neoplasia.

Methods and Materials: CTC datasets were obtained by abdominal CT scanning according to established protocols. The raw datasets were downloaded to a standard PC workstation and analysed using our novel software. The first phase of the analysis process involved extraction, or segmentation of a model of the colon lumen from the data set and calculation the centreline for this model. The centreline was subsequently used for automating intraluminal navigation. The second phase of the analysis process involved flagging potential colonic lesions, locating anomalies projecting from the colonic mucosa and flagging them as potential lesions based on their size and morphology. The analysis results were viewed using several visualisation techniques, including 2D, standard 3D and “virtual reality” stereo.

Results: We have used 5 CT datasets to date for analysis. This technique takes a mean time of 57 seconds (range 48 – 72) to analyse the raw datasets for review by an experienced radiologist and reduces review time by up to 50%. Although still in the early stages of development, the automated-flagging algorithm can detect polyps as small as 5mm and can cater for several different morphologies.

Conclusion: We have developed a technique for analysing CTC datasets that is rapid, accessible, and comparably inexpensive. Validation of this software is currently taking place. This technique increases the potential uses of CTC in screening individuals for colorectal neoplasia, by reducing viewing-time needed to detect these lesions.

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