Yasutaka Morimoto

Endoscopic submucosal dissection for colorectal tumors: technical difficulties and rate of perforation

BACKGROUND AND STUDY AIM Endoscopic submucosal dissection (ESD) for colorectal tumors is not generally recommended because of the technical difficulties and complications, including perforation. These aspects of ESD are thoroughly analyzed in our retrospective study. PATIENTS AND METHODS We studied 105 colorectal tumors, from 100 patients, that were treated by ESD at the Kyoto Prefectural University of Medicine or Nara City Hospital between 2005 and 2008. We analyzed tumor size, operation time, rate of en bloc resection, and complications. In addition, we thoroughly investigated the cases of perforation. RESULTS The average tumor size was 30.4 mm; average operation time, 102 min; and rate of en bloc resection, 88.5 %. Perforation occurred in 10.4 % of the ESD procedures. Of the 11 perforations, 8 were detected during ESD and treated by clip closure during endoscopy, while 3 were evident only on subsequent routine computed tomography (CT); these were also managed conservatively. A case of postoperative hemorrhage was also observed. CONCLUSIONS ESD effectively achieved a high rate of en bloc resection. However, the perforation rate was substantial; hence, improvement in the ESD method is required. The outcomes of ESD, especially for early colorectal malignancies, need to be assessed further.

Absence of pseudomembranes in Clostridium difficile-associated diarrhea in patients using immunosuppression agents.

Objective. Clostridium difficile is a major cause of diarrhea in hospitalized patients. Although pseudomembranes are crucial evidence for diagnosis of C. difficile-associated diarrhea (CDAD), some cases do not show any pseudomembranes. The aim of this study was to verify the hypothesis that pseudomembranes are not generated in immunosuppressed patients because of the absence of immunoreactions. Material and methods. We investigated the endoscopic findings of patients with ulcerative colitis (UC) or who had received hematopoietic stem cell transplantation, and who presented with C. difficile toxin A and had undergone colonoscopy between April 2002 and July 2007 at our institutes. Results. In 4 patients the diagnosis was UC and C. difficile infection, and in another 4 patients the diagnosis was CDAD after hematopoietic stem cell transplantation. None of these cases showed pseudomembranes. Shallow ulcers were found in all four cases with UC. Only non-specific findings were obtained for the CDAD patients after hematopoietic stem cell transplantation. Conclusions. Pseudomembranes, the typical evidence for CDAD, were not detected in any patients using immunosuppressive agents. Additional bacterial examination is therefore essential when UC becomes exacerbated and when patients present with diarrhea after hematopoietic stem cell transplantation, even in the absence of pseudomembranes.

Efficacy of magnifying endoscopy with flexible spectral imaging color enhancement in the diagnosis of colorectal tumors.

BackgroundMagnifying endoscopy with flexible spectral imaging color enhancement (FICE) is an image-enhanced endoscopy that captures the surface and vascular patterns of colorectal tumors. We evaluated and compared FICE magnification to narrow-band imaging (NBI) magnification.MethodsFlexible spectral imaging color enhancement or NBI magnification was performed to the visualize surface and vascular patterns of colorectal tumors, classified into 4 types: Type A, Type B, Type C1/C2, and Type C3, as previously reported. A total of 235 colorectal tumors were examined. The correlations between classifications found by FICE or NBI magnification and histopathological diagnoses were examined. Image evaluation was validated by assessing inter-observer and intra-observer agreements on examinations.ResultsTwenty-eight hyperplastic polyps (HPs), 115 tubular adenomas (TAs), 72 mucosal and slightly invaded submucosal cancers (M-sSM), and 20 massively invaded submucosal cancers (mSM) were diagnosed. By FICE magnification, HP and TA were observed in 93.3 and 6.7% of Type A (15 lesions), respectively. TA, M-sSM, and HP were observed in 82.6, 15.4, and 2.0% of Type B (52 lesions), respectively. M-sSM, TA, and mSM were observed in 50.0, 46.0, and 4.0% of Type C1/2 (50 lesions), respectively. mSMs were observed in all 7 Type C3 lesions. In diagnosing mSM in Type C3, the sensitivity and specificity of FICE magnification were 77.7 and 100%, respectively, compared to those of NBI, at 63.6 and 99.0%, respectively. Imaging evaluation was validated accurately by intra- and intra-observer measurements showing consistent results.ConclusionsThe classification of colorectal tumors by FICE magnification correlated well with the histopathological diagnoses, similar to findings for NBI magnification. FICE magnification can be evaluated accurately with the same diagnostic classifications as those used for NBI magnification.

Efficacy of hyaluronic acid in endoscopic mucosal resection of colorectal tumors

Background and Aim:  Endoscopic mucosal resection (EMR) is the standard procedure for colorectal tumors. High mucosal elevation by submucosal injection is important for definite en bloc resection and the prevention of perforation. Hyaluronic acid (HA) is a reportedly useful injection solution for high and long‐lasting mucosal elevation, but the ideal HA concentration for optimization of mucosal elevation maintenance, injection pressure, and cost is unknown. In the present study, we assessed the appropriate concentration of HA for EMR.

The detection of surface patterns by flexible spectral imaging color enhancement without magnification for diagnosis of colorectal polyps

PurposeFlexible spectral imaging color enhancement (FICE), or image-enhanced endoscopy, can enhance visualization of surface and vascular patterns of colorectal polyps. Resolution of FICE has recently been improved. We evaluated diagnostic accuracy for neoplastic and non-neoplastic colorectal polyp differentiation with detection of surface patterns by FICE without magnification.MethodsRetrospective analysis of 151 colorectal polyps evaluated by FICE without magnification was performed. Neoplastic surface patterns were defined as tubular and oval pit. We aimed to determine sensitivity, specificity, positive and negative predictive values (PPV and NPV), and accuracy in correlating diagnosis by FICE without magnification with histology. Moreover, findings were compared to those of white-light endoscopy (WL) and chromoendoscopy (CHR).ResultsOf the 151 colorectal polyps, 95 were identified as neoplastic and 56 were identified as non-neoplastic. FICE without magnification had a sensitivity of 89.4%, specificity of 89.2%, PPV of 93.4%, NPV of 83.3%, and accuracy of 89.4%. The accuracy of FICE value was higher than that of WL (sensitivity of 74.7%, specificity of 73.2%, PPV of 82.5%, NPV of 63.0%, and accuracy of 74.1%) and was worse than that of CHR (sensitivity of 96.8%, specificity of 89.2%, PPV of 93.9%, NPV of 96.1%, and accuracy of 94.7%). Imaging evaluation was validated by inter-/intra-observer measurements, demonstrating consistent results.ConclusionsThe detection of surface patterns by FICE without magnification is useful for differential diagnosis of colorectal polyps. We believe that FICE without magnification is more convenient and easier method than CHR.

Evaluation of autofluorescence colonoscopy for diagnosis of superficial colorectal neoplastic lesions

Background and aimAutofluorescence (AF) imaging, which can potentially differentiate tissue types based on differences in fluorescence emission, may be useful in the diagnosis and treatment of colorectal malignancies. This study was designed to assess the potential usefulness of AF colonoscopy for evaluating superficial colorectal neoplastic lesions.MethodsA total of 49 colorectal lesions in 43 patients were investigated. All superficial colorectal neoplastic lesions were identified with white light (WL) colonoscopy. Each detected lesion was investigated by WL colonoscopy, AF colonoscopy, and chromoendoscopy using 0.2% indigo carmine dye. Three endoscopists, blinded to each patients history, evaluated the still images (as obtained with these three methods) in random order and evaluated their influence on the assessment of lesion visualization. All the lesions were biopsied or resected endoscopically, with the pathological results used as the gold standard.ResultsFor visualization of the surface appearance and differences in color of the lesions compared with the surrounding mucosa, AF colonoscopy was superior to WL colonoscopy (p < 0.01) and comparable to chromoendoscopy (Mann–Whitney U test). For visualization of the circumferential margin, AF colonoscopy was superior to WL colonoscopy (p < 0.05) but inferior to chromoendoscopy (p < 0.01).ConclusionsAF colonoscopy may be a valuable tool for detection and diagnosis of superficial colorectal neoplastic lesions.

Clostridium difficile-associated diarrhea with hematochezia is associated with ulcer formation.

Objective. Clostridium difficile-associated diarrhea (CDAD) is a well-known iatrogenic infection with typical endoscopic features including pseudomembranes and intervening normal mucosa. Clinically, diarrhea frequently occurs, but occurrence of hematochezia is rare. The objective of this study was to investigate the background and endoscopic features of CDAD patients with hematochezia. Material and methods. The endoscopic and clinical findings in 12 patients who showed evidence of C. difficile toxin A and who underwent colonoscopy between April 2002 and July 2007 were investigated retrospectively. Results. Eight patients were diagnosed as having CDAD and 4 patients had a diagnosis of ulcerative colitis. Six of the patients with CDAD presented with hematochezia, and 4 of them were diagnosed with hematological malignancies and received anticancer chemotherapy. Colonic ulcer was demonstrated in all CDAD patients with hematochezia, and bleeding from the ulcer was endoscopically confirmed in all of them. Conclusions. CDAD accompanied by hematochezia is closely associated with ulcer formation. Ulcers are thought to occur during recovery from nadir after anticancer treatment, and white blood cells appear to be essential for their formation. Physicians should therefore pay close attention to the occurrence of colonic ulcer, especially in patients with CDAD during recovery from nadir.

High incidence of metachronous advanced adenoma and cancer after endoscopic resection of colon polyps ≥20 mm in size.

There are limited studies on incidence rates of metachronous neoplastic lesions after resecting large colorectal polyps. In the present study, we analyzed metachronous lesions after endoscopic resection of colorectal polyps ≥20 mm in size.