Colorectal polyp segmentation method based on fusion of transformer and cross-level phase awareness / 生物医学工程学杂志

In order to address the issues of spatial induction bias and lack of effective representation of global contextual information in colon polyp image segmentation, which lead to the loss of edge details and mis-segmentation of lesion areas, a colon polyp segmentation method that combines Transformer and cross-level phase-awareness is proposed. The method started from the perspective of global feature transformation, and used a hierarchical Transformer encoder to extract semantic information and spatial details of lesion areas layer by layer. Secondly, a phase-aware fusion module (PAFM) was designed to capture cross-level interaction information and effectively aggregate multi-scale contextual information. Thirdly, a position oriented functional module (POF) was designed to effectively integrate global and local feature information, fill in semantic gaps, and suppress background noise. Fourthly, a residual axis reverse attention module (RA-IA) was used to improve the network's ability to recognize edge pixels. The proposed method was experimentally tested on public datasets CVC-ClinicDB, Kvasir, CVC-ColonDB, and EITS, with Dice similarity coefficients of 94.04%, 92.04%, 80.78%, and 76.80%, respectively, and mean intersection over union of 89.31%, 86.81%, 73.55%, and 69.10%, respectively. The simulation experimental results show that the proposed method can effectively segment colon polyp images, providing a new window for the diagnosis of colon polyps.

Impacto da retroflexão na detecção de lesões de cólon proximal: avaliação de 393 pacientes em hospital privado terciário / Impact of retroflexed view on the detection of lesions in the proximal colon: assessment of 393 patients in a private tertiary hospital

ABSTRACT BACKGROUND: The gold standard test for colorectal cancer screening the colonoscopy. Although this is the test of choice, colonoscopy misses a significant number of lesions, mainly in the proximal colon. With the purpose of reducing the number of lesions missed, new techniques have been studied, amongst them, retroflexed view in the right side of the colon and the second direct forward view. OBJECTIVE: Assessing the safety of the retroview in the proximal colon (cecum and ascending colon), its impact on the detection of lesions in the proximal colon and its advantage over the double right forward view using adenoma detection rate and adenoma miss rate. METHODS: Three hundred and ninety-three patients who came to Hospital Mater Dei to undergo colonoscopy from March to July 2017, prospectively. Out of these, 372 were included in the study based on the following exclusion criteria: being under 18 years of age, inadequate bowel preparations (Boston scale <7), history of colectomy, inflammatory bowel disease or polypoid diseases. First, an endoscopist inserted the colonoscope into the cecum and examine the cecum and the ascending colon with a forward view twice. In the third insertion into the cecum, retroflexed view was performed, cecal mucosa was examined until the hepatic flexure in search of polyps missed on forward view. All lesions found were resected and sent for histological analysis. RESULTS: In 334 (89.8%) patients, retroflexed view was performed successfully, 65.8% of failures were attributed to the loops of the device which prevented the maneuver. The direct view identified 175 polyps in the proximal colon in 102 people. Retroflexed view detected 26 polyps missed by the direct view in 24 (6.5%) people, with a missing rate of 12.9% in the test with only the forward view. Out of the 26 polyps found in retroview, 21 (80.76%) were adenomas, one of them with a high-grade dysplasia. Eleven patients had polyps seen only in retroflexed view. Retroview has increased the polyp detection rate from 27.41% to 31.72% and the adenoma detection rate from 21.77% to 25%. The adenoma miss rate by the double direct view was 12.8%. Without the retroview, one polyp in every 13.91 colonoscopies would be missed (number needed to treat - NNT=13.91). There was no adverse event. CONCLUSION: The retroflexed view technique in the proximal colon was shown to be safe, fast and feasible in most cases. It increased the adenoma detection rate and was shown to be advantageous in this study wit benefit beyond the double direct view.

RESUMO CONTEXTO: O exame padrão ouro para rastreamento de câncer colorretal é a colonoscopia. Apesar de ser o exame de escolha, a colonoscopia perde um número não desprezível de lesões, principalmente no cólon proximal. Com a intenção de reduzir a perda de lesões, novas técnicas são estudadas, dentre elas, a retroflexão em cólon direito e a segunda visão frontal direta. OBJETIVO: Avaliar a segurança da retrovisão no cólon proximal (ceco e cólon ascendente), o seu impacto na detecção de lesões em cólon proximal e sua superioridade sobre a dupla visão frontal direta usando taxa de detecção de adenoma e taxa de adenoma perdido. MÉTODOS: Foram avaliados 393 pacientes de forma prospectiva que procuraram o Hospital Mater Dei para realizar colonoscopia entre março e julho de 2017. Desses, 372 foram incluídos baseados nos critérios de exclusão: menores de 18 anos, preparos intestinais inadequados (escala de Boston <7), com antecedente de colectomia, doença inflamatória intestinal ou síndromes polipoides. Primeiramente um endoscopista realizou a inserção do colonoscópio até o ceco e examinou o ceco e o cólon ascendente em visão frontal por duas vezes. Na terceira reinserção até o ceco era realizada a retroflexão e inspeção da mucosa do ceco até a flexura hepática em busca de pólipos perdidos à visão frontal. Todas lesões encontradas foram ressecadas e enviadas para análise histológica. RESULTADOS: Em 334 (89,8%) pacientes a retroflexão foi realizada com sucesso, 65,8% dos insucessos foram atribuídos a alças no aparelho que impediram a manobra. A visão direta identificou 175 pólipos no cólon proximal em 102 pessoas. A retroflexão detectou 26 pólipos perdidos pela visão direta em 24 (6,5%) pessoas, com uma taxa de perda de 12,9% no exame apenas em visão frontal. Dos 26 pólipos encontrados em retrovisão, 21 (80,76%) eram adenomas, um deles com displasia de alto grau. Onze pacientes tinham pólipos vistos apenas em retroflexão. A realização da retrovisão aumentou a taxa de detecção de pólipo de 27,41% para 31,72% e a taxa de detecção e adenomas de 21,77% para 25%. A taxa de adenoma perdido pela dupla visão direta foi de 12,8%. Se a retrovisão não fosse realizada, um pólipo a cada 13,91 colonoscopias seria perdido (NNT=13,91). Não houve nenhum evento adverso. CONCLUSÃO: A técnica de retroflexão em cólon proximal mostrou-se segura, rápida e factível na maioria dos casos. Ela aumentou a taxa de detecção de adenomas e mostrou-se soberana neste estudo com benfeitorias além da dupla visão direta.

Caracterização morfológica da abertura de glândulas colônicas usando imagens de microscopia de autofluorescência / Morphological characterization of colorectal pits using autofluorescence microscopy images

ABSTRACT BACKGROUND: Colorectal cancer is one of the most prevalent pathologies. Its prognosis is linked to the early detection and treatment. Currently diagnosis is performed by histological analysis from polyp biopsies, followed by morphological classification. Kudo's pit pattern classification is frequently used for the differentiation of neoplastic colorectal lesions using hematoxylin-eosin stained samples. Few articles have reported this classification with image software processing, using exogenous markers over the samples. The processing of autofluorescence images is an alternative that could allow the characterization of the pits from the crypts of Lieberkühn, bypassing staining techniques. OBJECTIVE: Processing and analysis of widefield autofluorescence microscopy images obtained by fresh colon tissue samples from a murine model of colorectal cancer in order to quantify and characterize the pits morphology by measuring morphology parameters and shape descriptors. METHODS: Adult male BALB/cCmedc strain mice (n=27), ranging from 20 to 30 g, were randomly assigned to four and five groups of treated and control animals. Colon samples were collected at day zero and at fourth, eighth, sixteenth and twentieth weeks after treatmentwith azoxymethane. Two-dimensional (2D) segmentation, quantification and morphological characterization of pits by image processing applied using macro programming from FIJI. RESULTS: Type I is the pit morphology prevailing between 53 and 81% in control group weeks. III-L and III-S types were detected in reduced percentages. Between the 33 and 56% of type I was stated as the prevailing morphology for the 4th, 8th and 20th weeks of treated groups, followed by III-L type. For the 16th week, the 39% of the pits was characterized as III-L type, followed by type I. Further, pattern types as IV, III-S and II were also found mainly in that order for almost all of the treated weeks. CONCLUSION: These preliminaries outcomes could be considered an advance in two-dimensional pit characterization as the whole image processing, comparing to the conventional procedure, takes a few seconds to quantify and characterize non-pathological colon pits as well as to estimate early pathological stages of colorectal cancer.

RESUMO CONTEXTO: O câncer colorretal é uma das patologias mais prevalentes. Seu prognóstico é ligado à detenção e ao tratamento precoces. Atualmente o diagnóstico é realizado por análise histológica de biópsias de pólipo, seguida de classificação morfológica. A classificação de padrões de Kudo é frequentemente utilizada para a diferenciação de lesões colorretais neoplásicas usando amostras coradas por hematoxilina-eosina. Poucos artigos relatam esta classificação com utilização de processamento por software de imagem, utilizando marcadores exógenos sobre as amostras. O processamento de imagens de autofluorescência é uma alternativa que pode permitir a caracterização do padrão das criptas de Lieberkühn, contornando técnicas de coloração. OBJETIVO: Analisar, quantificar e caracterizar a morfologia do padrão das criptas medindo os parâmetros morfológicos e descritores de forma, através do processamento e análise de imagens de microscopia de autofluorescência de campo de Widefield obtidas em amostras de tecido de cólon fresco a partir de um modelo murino de câncer colorretal. MÉTODOS: Camundongos machos adultos BALB/cCmedc (n=27), variando de 20 a 30 g, foram distribuídos aleatoriamente em quatro e cinco grupos de animais tratados e de controle. As amostras de cólon foram coletadas no dia zero e na 4ª, 8ª, 16ª e 20ª semanas após o tratamento com azoxometano. Segmentação bidimensional (2D), quantificação e caracterização morfológica do padrão das criptas por processamento de imagem aplicados utilizando programação macro de FIJI. RESULTADOS: O tipo I é a morfologia da cripta prevalente entre 53% e 81% semanas do grupo controle. Os tipos III-L e III-S foram detectados em porcentagens reduzidas. A morfologia do tipo I entre os 33% e 56% foi constatada como a predominante para as 4ª, 8ª e 20ª semanas de grupos tratados, seguidos pelo tipo III-L. Para a 16ª semana, os 39% dos padrões das criptas foram caracterizados como tipo III-L, seguidos pelo tipo I. Além disso, os tipos de padrão como IV, III-S e II também foram encontrados principalmente nessa ordem para quase todas as semanas tratadas. CONCLUSÃO: Estes resultados preliminares podem ser considerados um avanço na caracterização bidimensional da cripta como um processamento integral da imagem, comparando-se ao procedimento convencional; demora-se alguns segundos a mais para quantificar e caracterizar pontos não-patológicos, bem como para estimar estágios patológicos precoces do câncer colorretal.

Effect of Reducing Abdominal Compression during Prone CT Colonography on Ascending Colonic Rotation during Supine-to-Prone Positional Change

OBJECTIVE: To determine the effect of reduced abdominal compression in prone position on ascending colonic movement during supine-to-prone positional change during CT colonography (CTC). MATERIALS AND METHODS: Eighteen consecutive patients who had undergone prone CTC scanning with cushion blocks placed under the chest and hip/thigh to reduce abdominal compression and had confirmed sessile polyps > or = 6 mm in the well-distended, straight, mid-ascending colon, were included. Radial location along the ascending colonic luminal circumference (degrees) was measured for 24 polyps and 54 colonic teniae on supine and prone CTC images. The supine-to-prone change ranging between -180degrees and +180degrees (- and + for internal and external colonic rotations, respectively), was determined. In addition, possible causes of any ascending colonic rotations were explored. RESULTS: Abdominal compression during prone CTC scanning completely disappeared with the use of cushion blocks in 17 of 18 patients. However, some degrees of ascending colonic rotation were still observed, with the radial location changes of -22degrees to 61degrees (median, 13.9degrees) for the polyps and similar degrees for teniae. Fifty-four percent and 56% of polyps and teniae, respectively, showed changes > 10degrees. The radial location change of the polyps was significantly associated with the degree of anterior shift of the small bowel and mesentery (r = 0.722, p < 0.001) and the degree of posterior displacement of the ascending colon (r = 0.566, p = 0.004) during supine-to-prone positional change. CONCLUSION: Ascending colonic rotation upon supine-to-prone positional change during CTC, mostly in the form of external rotation, is not eliminated by removing abdominal compression in prone position.

Colonoscopía virtual: realidad en un hospital público / Virtual colonoscopy: reality in a public hospital

Colon cancer is the third cause of death by cancer in Chile. Virtual CT colonoscopy (VC) is a non-invasive imaging technique in development. The most common indications of VC are screening of colonic polyp, incomplete conventional colonoscopy and staging of colorectal tumors. The objective of our study is to show our experience with this method in the Radiology Unit of Hospital Padre Hurtado. We reviewed 15 VC, corresponding to 15 patients (10 female and 5 male), with ages between 18 and 75. Six exams showed no significant findings (40%), 4 diverticular diseases (26,6%), 3 colon cancers (20%), and 2 familial polyposis (13,3%). VC proved to be an accesible method, well tolerated by the patients, less invasive than conventional colonoscopy and with no complications in our series. It also constitutes for us an excellent study method in patients where conventional colonoscopy is incomplete. We obtained an adecuate correlation with conventional colonosocopy, when this method was performed. Evaluation of the data obtained from VC requires a trained radiologist and, in some occasions, prolonged time for analysis and interpretation of the results.

El cáncer de colon es la tercera causa de muerte por cáncer en Chile. La colonoscopía virtual (CV) es una técnica de imagen no invasiva en desarrollo. Sus indicaciones habituales son: screening y detección de pólipos en el colon, colonoscopía convencional fallida o incompleta y, etapificación de tumores colorrectales. El objetivo de nuestro trabajo fue mostrar nuestra experiencia con este método diagnóstico en el Servicio de Imagenología del Hospital Padre Hurtado. Se revisaron 15 exámenes de CV que correspondieron a 15 pacientes (10 mujeres y 5 hombres), con edades entre 18 y 75 años. Los estudios mostraron 6 casos sin hallazgos patológicos significativos (40%), 4 enfermedades diverticulares (26,6%), 3 neoplasias de colon (20%) y 2 poliposis familiares (13,3%). La colonoscopía por TC resultó ser una técnica accesible, bien tolerada por los pacientes, menos invasiva que la fibrocolonoscopía y sin complicaciones. Además, para nosotros constituye un excelente método de estudio, sobretodo en aquellos pacientes en los cuales la fibrocolonoscopía resultó fallida o incompleta. Se obtuvo una buena correlación con colonoscopía convencional, cuando ésta se pudo realizar. El post-proceso de los datos requiere de entrenamiento del radiólogo y, algunas veces, tiempo prolongado para el análisis e interpretación de los resultados.

Fundamental Elements for Successful Performance of CT Colonography (Virtual Colonoscopy)

There are many factors affecting the successful performance of CT colonography (CTC). Adequate colonic cleansing and distention, the optimal CT technique and interpretation with using the newest CTC software by a trained reader will help ensure high accuracy for lesion detection. Fecal and fluid tagging may improve the diagnostic accuracy and allow for reduced bowel preparation. Automated carbon dioxide insufflation is more efficient and may be safer for colonic distention as compared to manual room air insufflation. CT scanning should use thin collimation of < or =3 mm with a reconstruction interval of < or =1.5 mm and a low radiation dose. There is not any one correct method for the interpretation of CTC; therefore, readers should be well-versed with both the primary 3D and 2D reviews. Polyps detected at CTC should be measured accurately and reported following the "polyp size-based" patient management system. The time-intensive nature of CTC and the limited resources for training radiologists appear to be the major barriers for implementing CTC in Korea.

Diagnosis of coloretal polyps by hydrocolonic sonography in children with rectal bleeding

Because of the inherent danger and associated discomfort of invasive procedures such as colonoscopy or double contrast barium enema involving exposure to radiation, we studied the value of hydrocolonic sonography in the diagnosis of colorectal polyps in children with rectal bleeding. From March 2005 to January 2006, 46 children from 2.5-11 years of age presented with hematochezia were examined by means of hydrocolonic sonography and colonoscopy. On colonoscopy, 21 patients had normal results, 19 had polyps, 3 had proctitis, 2 had lymphonodular hyperplasia and 1 had anal fissure. Only 7 of 19 colorectal polyps were diagnosed by conventional abdominal sonography [37%], whereas hydrocolonic sonography permitted the diagnosis of 17 [89.5%] with a specificity equal to 92.5%. In comparison with colonoscopy, positive predictive value of hydrocolonic sonography was 89.4% and negative predictive value was 92.5%. Hydrocolonic sonography is a accurate and safe approach to evaluating children with rectal bleeding. Thus, it can be regarded as an appropriate replacement of barium enema

Tratamiento endoscópico de los pólipos de colon y de recto / Treatment endoscópico of the colon polyps and of right

Se revisaron 100 historias clínicas de pacientes consultados en los años 1998 y 1999 en los servicios de Coloproctología, Gastroenterología y Medicina Interna del Hospital Clinicoquirúrgico Docente "10 de Octubre", con los diagnósticos clínico-imagenológico y endoscópico de pólipos de colon y de recto. Se les realizó biopsia, y se halló 50 por ciento de pólipos adenomatosos benignos y lesiones de alto riesgo como: adenomas tubulares (15 por ciento), adenomas vellosos (12 por ciento), adenocarcinomas (10 por ciento), pólipos con lesiones atípicas (3 por ciento). Se determinó en el estudio los beneficios de la resección endoscópica que se realizó en 85 por ciento de los pacientes, así como el seguimiento de las lesiones según su histología. Se encontraron 11 pacientes con recidivas entre 6 meses y 1 año: 6 pacientes con pólipos adenomatosos originales que no cambiaron su histología y los 5 restantes con adenomas tubulares y vellosos, que recidivaron como adenocarcinomas(AU)

100 medical histories of patients with the clinico-imaging and endoscopic diagnoses of colonic and rectal polyps seen at the services of Choloproctology, Gastroenterology and Internal Medicine of "10 de Octubre" Clinical and Surgical Hospital in 1998 and 1999 were reviewed. Biopsy was performed and 50 percent of benign adenomatous polyps and high risk lesions as: tubular adenomas (15 percent), villous adenomas (12 percent), adenocarcinomas (10 percent) and polyps with atypical lesions (3 percent) were found. The benefits of endoscopic resection performed in 85 percent of the patients, as well as the follow-up of the lesions according to their histology, were determined in the study. 11 patients had recurrences between 6 months and 1 year: 6 patients with original adenomatous polyps that did not change their histology and the other 5 with tubular and villous adenomas that relapsed as adenocarcinomas(AU)