Search PubMed⌕ Search

Biomedical subjects

S S Cross

Publications and source records attributed to S S Cross.

At least 37 records · Page 2Linked to original sources
PubMed2004

An evaluation of colorectal endoscopic mucosal resection using high-magnification chromoscopic colonoscopy: a prospective study of 1000 colonoscopies.

BACKGROUND AND STUDY AIMS: Endoscopic mucosal resection provides an alternative to surgery for resection of sessile and flat colorectal lesions. High-magnification chromoscopic colonoscopy may allow early detection and anticipate histological diagnosis by identifying colonic crypt patterns. The aim of the present study was to assess the efficacy and safety of en-bloc endoscopic mucosal resection with high-magnification chromoendoscopy in the management of sessile and flat colorectal lesions </= 20 mm. PATIENTS AND METHODS: A single endoscopist using high-magnification chromoendoscopy prospectively examined 1000 patients attending for routine colonoscopy. Patients were selected for inclusion in the study if they were considered to be at high risk for underlying colorectal neoplasia or polyps. Within the study period, 1000 patients (29 %) qualified for entry from a total of 3480 colonoscopies conducted in our institution. Endoscopic mucosal resection was carried out in appropriate flat and sessile lesions. RESULTS: Endoscopic mucosal resection was carried out in 599 lesions. Complete histological resection was confirmed in 576 (96 %). Perforation occurred in one patient (0.2 %) and bleeding in 12 (2 %). A total of 254 lesions (40 %; excluding hyperplasia/metaplasia) were flat or depressed, and 374 (60 %) were sessile. Fifty-eight flat lesions (23 %) contained high-grade dysplasia or beyond, compared to 33 sessile lesions (9.0 %; P = 0.001). After resection, 21 lesions were upgraded histologically, with 17 being defined as adenoma with high-grade dysplasia or beyond. CONCLUSIONS: This study confirms that flat adenomas and carcinomas occur in the West and demonstrates the malignant potential of such lesions, which can be managed successfully using endoscopic techniques. Endoscopic mucosal resection with high-magnification chromoscopy is a safe and effective form of treatment for sessile or flat colorectal lesions. Complete resection can improve the accuracy of histopathological diagnosis. However, colonoscopists require training in these procedures in order to improve the rate of colorectal cancer detection.

Adenoma↗
PubMed2004

Endoscopic morphological anticipation of submucosal invasion in flat and depressed colorectal lesions: clinical implications and subtype analysis of the kudo type V pit pattern using high-magnification-chromoscopic colonoscopy.

OBJECTIVE: Focal submucosal invasive colorectal cancers (submucosa-sm1) can be managed by endoscopic mucosal resection (EMR) as local lymph node metastasis (LNM) are rare. Lesions are usually flat, depressed or mixed. In deeper vertical submucosal invasion (sm2-3) LNM rates exceed 10-15%. EMR within this group can be complicated by perforation, noncurative resection and may leave LNM untreated. It is therefore essential to differentiate accurately focal sm1 disease from submucosal sm2/3 disease. The aim of this study was to evaluate the relationship between the invasive type V pit pattern using high-magnification-chromoscopic-colonoscopy (HMCC) and submucosal invasive depth for flat and depressed colorectal lesions. METHODS: Total colonoscopy was performed by a highly selected single endoscopist using the Olympus C240Z on 850 patients between January 2001 and July 2003. Kudo type V pits were identified using 0.05% crystal violet (CV) applied directly to the lesion using a steel tipped catheter. Type V pits were graded into class V(n)A-C as described by Nagata. Morphology was documented using the Japanese Research Society classification (JRSC). Histological sections, with reference to mucosal invasive characteristics, acquired using EMR or surgical excision were then compared with the pit pattern. RESULTS: Fifty-one lesions showed a type V pit pattern. The kappa coefficient of agreement between pit the type V pit pattern and histologically confirmed submucosal invasion was 0.51 (95% CI). Following resection, 97% of lesions were correctly anticipated to have sm2 + invasion using pit type Vn(B) and Vn(C) as clinical indicators of invasive disease. Specificity was low at 50% with an accuracy of 78%. CONCLUSIONS: The type V pit pattern is useful for the in vivo staging of submucosal invasive depth in flat and depressed colorectal lesions and is as sensitive as conventional 7.5 MHz EUS. There was a tendency to over-stage lesions and hence the technique is limited by its low overall specificity.

Biopsy, Needle↗
PubMed2004

Efficacy of high magnification chromoscopic colonoscopy for the diagnosis of neoplasia in flat and depressed lesions of the colorectum: a prospective analysis.

BACKGROUND: High magnification chromoscopic colonoscopy (HMCC) permits the in vivo examination of the colorectal pit pattern, which has a high correlation with stereomicroscopic appearances of resected specimens. This new technology may provide an "optical biopsy" which can be used to aid diagnostic precision and guide therapeutic strategies. Conflicting data exist concerning the accuracy of this technique when discriminating neoplastic from non-neoplastic lesions, particularly when flat and depressed. AIM: To prospectively examine the efficacy of HMCC for the diagnosis of neoplasia in flat and depressed colorectal lesions using standardised morphological, pit pattern, and histopathological criteria. Clinical recommendations for the use of HMCC are made. METHODS: Total colonoscopy was performed on 1850 patients by a single endoscopist from January 2001 to July 2003 using the C240Z magnifying colonoscope. Identified lesions were classed according to the Japanese Research Society guidelines, and pit pattern according to Kudos modified criteria. Pit pattern appearances were then compared with histopathology. RESULTS: A total of 1008 flat lesions were identified. The sensitivity and specificity of HMCC in distinguishing non-neoplastic from neoplastic lesions were 98% and 92%, respectively. However, when using HMCC to differentiate neoplastic/non-invasive from neoplastic/invasive lesions, sensitivity was poor (50%) with a specificity of 98%. Diagnostic accuracy was not influenced by size or morphological classification of lesions. CONCLUSION: HMCC has a high overall accuracy at discriminating neoplastic from non-neoplastic lesions but is not 100% accurate. HMCC is a useful diagnostic tool in vivo but presently is not a replacement for histology. Requirements for further education and training in these techniques need to be addressed.

Adolescent↗
PubMed2004

Detecting diminutive colorectal lesions at colonoscopy: a randomised controlled trial of pan-colonic versus targeted chromoscopy.

BACKGROUND: Diminutive and flat colorectal lesions can be difficult to detect using conventional colonoscopic techniques. Previous data have suggested that pan-chromoscopy may improve detection rates. No randomised control trial has been performed examining detection rates of such lesions while controlling for extubation time and lavage effect. AIM: We conducted a randomised controlled trial of pan-colonic chromoscopic colonoscopy for the detection of diminutive and flat colorectal lesions while controlling for extubation time and lavage effect. METHODS: Consecutive patients attending for routine colonoscopy were randomised to either pan-chromoscopy using 0.5% indigo carmine (IC) or targeted chromoscopy (control group). A minimum diagnostic extubation time was set at eight minutes with controls undergoing a matched volume of saline wash. RESULTS: A total of 260 patients were randomised; 132 controls and 128 to pan-colonic chromoscopy. Extubation times did not differ significantly between the control (median 15 minutes (range 8-41)) and chromoscopy (median 17 minutes (range 8-39)) groups. The volume of IC used in the pan-chromoscopy group (median 68 ml (range 65-90)) and normal saline used in the control group (69 ml (range 60-93)) did not differ significantly. There was a statistically significant difference between the groups regarding the total number of adenomas detected (p<0.05) with significantly more diminutive (<4 mm) adenomas detected in the pan-chromoscopy group (p = 0.03). Pan-chromoscopy diagnosed more diminutive and flat lesions in the right colon compared with controls (p<0.05), with more patients with multiple adenomas (>3) detected using pan-chromoscopy (p<0.01). Hyperplastic lesions were more commonly detected in the pan-chromoscopy group compared with controls (p<0.001). More hyperplastic polyps were detected in the left colon (86% rectosigmoid) using chromoscopy compared with controls. CONCLUSION: Chromoscopy improves the total number of adenomas detected and enhances the detection of diminutive and flat lesions. Importantly, eight diminutive lesions had foci of high grade dysplasia. Chromoscopy may benefit patients, assuming a high risk of colorectal cancer, and help in risk stratification and planning follow up colonoscopy intervals.

Adenoma↗
PubMed2004

Colonoscopic resection of lateral spreading tumours: a prospective analysis of endoscopic mucosal resection.

BACKGROUND: Lateral spreading tumours are superficial spreading neoplasms now increasingly diagnosed using chromoscopic colonoscopy. The clinicopathological features and safety of endoscopic mucosal resection for lateral spreading tumours (G-type "aggregate" and F-type "flat") has yet to be clarified in Western cohorts. METHODS: Eighty two patients underwent magnification chromoscopic colonoscopy using the Olympus CF240Z by a single endoscopist. All patients had received a previous colonoscopy where an endoscopic diagnosis of lateral spreading tumour was made. All lesions were examined initially using indigo carmine chromoscopy to delineate contour followed by crystal violet for magnification crypt pattern analysis. A 20 MHz "mini probe" ultrasound was used if T2 disease was suspected. Following endoscopic mucosal resection, patients were followed up at 3, 6, 12, and 24 months using total colonoscopy. RESULTS: Eighty two lateral spreading tumours were diagnosed in 80 patients (32% (26/82) F-type and 68% (56/82) G-type). G-type lesions were larger than F-type (G-type mean 42 (SD 14) mm v F-type 24 (6.4) mm; p<0.01). F-type lesions were more common in the right colon (F-type 77% (20/26) compared with G-type 39% (22/56); p<0.01) and more often associated with invasive disease (stage T2) (66% (10/15) v 33% (5/15); p<0.001). Fifty eight lesions underwent endoscopic mucosal resection (G-type 64% (37/58)/F-type 36% (21/58)). Local recurrent disease was detected in 17% of patients (10/58), all within six months of the index resection. Piecemeal resection and G-type morphology were significantly associated with recurrent disease (p<0.1). Overall "cure" rates for lateral spreading tumours using endoscopic mucosal resection at two years of follow-up was 96% (56/58). CONCLUSIONS: Endoscopic mucosal resection for lateral spreading tumours, staged as T1, is a safe and effective treatment despite their large size. Endoscopic mucosal resection may be an alternative to surgery in selected patients.

Adult↗
PubMed2003

The role of flat and depressed colorectal lesions in colorectal carcinogenesis: new insights from clinicopathological findings in high-magnification chromoscopic colonoscopy.

High-magnification chromoscopic endoscopy is a new technique which has been recently introduced to the UK. This technology, initially pioneered by the Japanese in the 1980s, has changed our understanding of the pathogenesis of colorectal cancer and our subsequent therapeutic strategies aimed at the secondary prevention of cancer. Magnification colonoscopic techniques when combined with colonic chromoscopy (dye spraying of the colon) permit in vivo assessments of lesions at a magnification and resolution similar to a stereomicroscope. Furthermore, flat/depressed adenomas and cancers can be diagnosed with increasing frequency and new resection practices performed. This technique is known as endoscopic mucosal resection. As gastrointestinal endoscopists adopt these new techniques, close liaison with histopathologists is essential to provide the highest standards of diagnostic accuracy. The histopathologist also needs to be aware of the endoscopic findings when interpreting specimens and hence must understand new endoscopic terminologies and classification systems that accompany the introduction of new technologies and therapeutic techniques. This article describes the controversies relating to the flat and depressed colorectal lesion, where these new endoscopic technologies are ideally suited. It then provides a working description of high-magnification chromoscopic colonoscopy including the Japanese 'pit pattern' and morphological classification system-information which will be provided to histopathologists with specimens obtained by these new techniques. Finally, we describe the procedure of endoscopic mucosal resection, as the type and quality of specimens received for histopathological analysis will be highly influenced by these techniques.

Colonoscopy↗
PubMed2002

Telepathology: current status and future prospects in diagnostic histopathology.

Telepathology is the process of diagnostic histopathology performed on digital images viewed on a display screen rather than by conventional glass slide light microscopy. The technology of telepathology has radically improved over the past 5 years so that it is no longer the limiting factor in the diagnostic process. This review looks at the resources needed for dynamic and static telepathology, including image quality, computers and software interfaces, means of transmission and human resources. It critically analyses 32 published trials of telepathology, including some large prospective studies, in all areas of diagnostic histopathology including intraoperative frozen sections, routine and referral cases. New developments, including internet solutions and virtual microscopy, are described and there is analysis of the economics of telepathology within health care systems. The review concludes that all the necessary technology for telepathology is available, there is strong published evidence for a diagnostic accuracy comparable with glass slide diagnosis, in many contexts there is a clear-cut economic argument in favour of telepathology, and that the technique should now be integrated into mainstream diagnostic histopathology.

Humans↗
PubMed2002

Prospective validation of the Rockall risk scoring system for upper GI hemorrhage in subgroups of patients with varices and peptic ulcers.

OBJECTIVES: The Rockall risk assessment score was devised to allow prediction of the risk of rebleeding and death in patients with upper GI hemorrhage. The score was derived by multivariate analysis in a cohort of patients with upper GI hemorrhage and subsequently validated in a second cohort. Only 4.4% of patients included in the initial study had esophageal varices, and analysis was not performed according to the etiology of the bleeding. Our aim was to assess the validity of the Rockall risk scoring system in predicting rebleeding and mortality in patients with esophageal varices or peptic ulcers. METHODS: Admissions (n = 358) over 32 months to a single specialist GI bleeding unit were scored prospectively. The distribution of episodes of rebleeding and mortality by Rockall score were statistically analyzed using Fisher's exact test with 99% CIs calculated using a Monte Carlo method. The Child-Pugh score was determined in patients with esophageal varices. RESULTS: The Rockall score was predictive of both rebleeding and mortality in patients with variceal hemorrhage (both ps < 0.0005), as was the Child-Pugh score (p = 0.001 and p < 0.0005, respectively). The initial Rockall score was predictive of mortality in patients with peptic ulcers (p = 0.01), although the complete score was not (p > 0.05). The complete score did, however, predict rebleeding in these patients (p = 0.001). CONCLUSION: This is the first study to validate the Rockall score in specific subgroups of patients with esophageal varices or peptic ulcers and suggests that it is particularly applicable to variceal hemorrhage.

Adult↗
PubMed2002

Proactive management of histopathology workloads: analysis of the UK Royal College of Pathologists' recommendations on specimens of limited or no clinical value on the workload of a teaching hospital gastrointestinal pathology service.

AIMS: To investigate the effect on the workload of a gastrointestinal pathology service of implementing the recommendations of the Royal College of Pathologists' (RCPath) working party on specimens of limited or no clinical value (LONCV). METHODS: All endoscopic gastrointestinal pathology reports for the first three months of 2001 at a large teaching hospital were reviewed against the RCPath recommendations. Specimens in the category of LONCV were recorded and the final histopathology diagnosis noted. RESULTS: The biopsies in the LONCV category were 30% of oesophageal, 61% of gastric, 0.5% of duodenal, and 7% of colorectal origin. CONCLUSIONS: Implementing the RCPath recommendations would reduce the number of requests for the examination of gastrointestinal endoscopic specimens by 3500 specimens each year in this department. None of the specimens in the LONCV category showed an abnormality that could not have been detected by a more efficient and less invasive method. In the UK, where there is a severe shortage of trained histopathologists, the implementation of these recommendations would ensure that these scarce resources are not misused.

Biopsy↗
PubMed2002

Offline telepathology diagnosis of colorectal polyps: a study of interobserver agreement and comparison with glass slide diagnoses.

BACKGROUND/AIMS: Technological advances have produced telepathology systems with high quality colour images and reasonable transmission times. Most applications of telepathology have centred on the remote diagnosis of frozen sections or remote real time expert opinions. This study investigates the reproducibility and accuracy of offline telepathology as a primary diagnostic medium for routine histopathology specimens. METHODS: One hundred colorectal polyps (50 hyperplastic, 50 adenomatous) were presented in a randomised order to five histopathologists as offline images on a telepathology workstation. Six images of each case were used: the slide label, a low power scan of all material on the slide, and four higher magnification views. The times taken to prepare the images, and to make the diagnoses, were recorded. Interobserver agreement was measured with kappa statistics and compared with the glass slide diagnoses. RESULTS: The kappa statistics for the interobserver agreement on the telepathology images lay in the range of 0.90-1.00, which is interpreted as excellent agreement, and were significantly higher than those for the glass slide diagnoses (range, 0.84-0.98; p = 0.001). The median time taken to capture the images for a case was 210 seconds. The median time taken to make a diagnosis from the telepathology images was five seconds, which was significantly shorter than for the glass slide diagnoses (median, 13 seconds; p < 0.0005). CONCLUSIONS: Offline telepathology has the potential to be a primary diagnostic medium for routine histopathology with a high degree of reproducibility and short diagnosis times. Further studies are required to validate offline telepathology for different types of specimens and different operators of the image capture system.

Adenoma↗
PubMed2002

Discriminant histological features in the diagnosis of chronic idiopathic inflammatory bowel disease: analysis of a large dataset by a novel data visualisation technique.

BACKGROUND/AIMS: The histopathological assessment of endoscopic colorectal biopsies is important in the distinction between normality and chronic idiopathic inflammatory bowel disease, and between ulcerative colitis and Crohn's disease, in subjects with symptoms of bowel dysfunction. This study aims to use carefully defined histopathological observations on a large study population to produce systems that improve classification into these diagnostic categories. METHODS: Eight hundred and nine endoscopic colorectal biopsies with verified outcomes (165 normal, 473 ulcerative colitis, 171 Crohn's disease) were examined by a single experienced histopathologist and 20 defined features were recorded for each case using a novel graphical interface with reference images of each feature. These features, together with age and sex, were used to produce and test statistical classifiers using logistic regression and a novel growing cell structure technique. RESULTS: The distinction between chronic idiopathic inflammatory bowel disease and normality was made with a good level of performance by both statistical classifiers (with areas under the receiver operating characteristic curves above 0.80). The growing cell structure system selected features as discriminant that agreed with the published literature. Logistic regression produced a more variable selection of discriminant features because of the high correlation between many features. The distinction between ulcerative colitis and Crohn's disease was performed less accurately, with areas under the receiver operating characteristic curves of about 0.70. Again the features selected as discriminant broadly agreed with those in the published literature. CONCLUSIONS: Histopathological examination of endoscopic colorectal biopsies is an effective method of distinguishing between subjects with chronic idiopathic inflammatory bowel disease and normality, but less good at distinguishing between ulcerative colitis and Crohn's disease. The features selected as discriminant in this large statistical analysis broadly agree with those published in the literature from more qualitative studies.

Adolescent↗
PubMed2001

Observer accuracy in estimating proportions in images: implications for the semiquantitative assessment of staining reactions and a proposal for a new system.

BACKGROUND: The results of immunohistochemical staining are often assessed by semiquantitative scoring. However, these scoring systems are usually non-standardised and there has been little evaluation of the accuracy and reliability of this subjective assessment. AIMS: To assess the accuracy of observer estimation of proportions of objects in an image. METHODS: Images were generated that contained known proportions of pink squares in grids of 50 x 50 and 100 x 100 squares. Observers were shown each image for five seconds in random order and either estimated the proportion of pink squares or selected the image (from a pair of images) that contained the greater proportion of pink squares. The observers were four consultant histopathologists, seven trainee histopathologists, and six control non-histopathologists. RESULTS: The raw estimations of proportions showed a close correlation with the real proportions, with correlation coefficients of 0.94 and 0.95 for consultant and trainee histopathologists on the 50 x 50 grids. However, the performance in the comparison task was much higher, with an almost perfect classification for grids of equal size even when the proportions only differed by 5%. CONCLUSIONS: Histopathologists can estimate proportions of objects in an image with a reasonable degree of accuracy in this abstract test system. All observers, whether histopathologists or not, can discriminate between proportions that are only 5% different in equal sized image grids. This suggests that the generation and use of carefully calibrated reference images could greatly improve the accuracy and reliability of semiquantitative scoring of immunohistochemical or any other staining.

Clinical Competence↗