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

Mucosal imaging in colon polyps: New advances and what the future may hold

An expanding range of advanced mucosal imaging technologies have been developed with the goal of improving the detection and characterization of lesions in the gastrointestinal tract. Many technologies have targeted colorectal neoplasia given the potential for intervention prior to the development of invasive cancer in the setting of widespread surveillance programs. Improvement in adenoma detection reduces miss rates and prevents interval cancer development. Advanced imaging technologies aim to enhance detection without significantly increasing procedural time. Accurate polyp characterisation guides resection techniques for larger polyps, as well as providing the platform for the “resect and discard” and “do not resect” strategies for small and diminutive polyps. This review aims to collate and summarise the evidence regarding these technologies to guide colonoscopic practice in both interventional and non-interventional endoscopists.

Comparison of blue laser imaging and narrow band imaging for the differentiation of diminutive colorectal polyps: A randomized controlled trial

BACKGROUND

To compare the diagnostic efficacy of blue laser imaging (BLI)- bright and narrow band imaging (NBI) modes of image enhanced endoscopy (IEE) in differentiating neoplastic and non-neoplastic lesions of diminutive colorectal polyps.

METHODS

We conducted a prospective randomized controlled trial from September 2015 to July 2016. The participants were randomly assigned (1:1) for colonoscopy with polyp classification under NBI or BLI-bright mode without magnification. Histopathologic diagnosis was used as the gold standard.

RESULTS

Three hundred and twenty-four diminutive polyps in 164 patients were included for analysis (BLI: 162 polyps in 73 patients, NBI: 162 polyps in 91 patients). These polyps were located at colon proximal to sigmoid (61.1 and 58.0%) and rectosigmoid colon (38.9 and 42.0%) in the BLI and NBI groups, respectively. Most polyps (71.9%) were adenomatous with one malignant polyp (0.3%). BLI achieved 86.4% accuracy, 98.3% sensitivity, 55.6% specificity, 85.2% positive predictive value (PPV), and 92.6% negative predictive value (NPV), similar to NBI which exhibited 90.1% accuracy, 99.1% sensitivity, 67.4% specificity, 88.5% PPV, and 96.9% NPV in the diagnosis of adenomatous polyps. Based on the location of the polyp, both modes of IEE provided ≥ 95% NPV for diagnosis of adenomatous polyps at the rectosigmoid colon.

CONCLUSIONS

BLI-bright and NBI modes of IEE have similar accuracy in differentiation between neoplastic and non-neoplastic lesions of diminutive polyps. Both modes provided ≥ 90% NPV which allows for the adaptation of the American Society of Gastrointestinal Endoscopy "diagnose-and-leave" recommended strategy for diminutive polyps at the rectosigmoid colon.

Bupleuri Radix Prevents the Recurrences of Resected Colonic Polyps by Affecting Angiogenin-2-Induced Protein Kinase B/Akt Signaling

Aim

We aimed to explore the effects of Bupleuri Radix (BR) on the recurrence of resected colonic polyp (CP) by measuring angiogenin-2-induced protein kinase B (Ang PKB)/Akt signaling.

Method

The main ingredients of BR were extracted by using ethanol and measured by HPLC. One hundred twenty patients with CP >10 mm who underwent resected surgery were randomly allocated to an aspirin (AG) or a BR medicine (BG) group. The allocation ratio was 1 : 1 and the intervention duration was one year. The recurrence rate of resected CP was investigated and the plasma levels of Ang PKB/Akt and inflammatory cytokines were measured using ELISA kits. After one-year surgery, side effects were recorded. The relationship between the serum levels of the main compounds of BR and plasma levels of Ang PKB/Akt was analyzed.

Results

The main ingredients of CP are paeoniflorin, baicalin, saikosaponin A, and bupleurum saponin B2. Recurrence of resected CP was found in 17 patients from the AG group and eight patients from the BG group after one-year follow-up (p < 0.05). The levels of angiogenin-2 II and PKB/Akt in the AG group were higher than those in the BG group (p < 0.05). Meanwhile, BR treatment reduced the plasma levels of TNF-α, IL-1β, and IL-6, and increased the level of IL-10(p < 0.05). Inflammatory cytokines are important factors that affect the recurrence of resected CP. Serum paeoniflorin, baicalin, saikosaponin A, and bupleurum saponin B2 in BR had a strong negative relationship with the plasma levels of Ang PKB/Akt.

Conclusion

BR significantly reduces the recurrence risk of resected CP by affecting Ang PKB/Akt signaling.

Virtual Chromoendoscopy With FICE for the Classification of Polypoid and Nonpolypoid Raised Lesions in Ulcerative Colitis

GOALS

The aim of this study was to analyze the performance of Fuji Intelligent Color Enhancement (FICE) using the classification of Kudo in the differentiation of neoplastic and non-neoplastic raised lesions in ulcerative colitis (UC).

BACKGROUND

The Kudo classification of mucosal pit patterns is an aid for the differential diagnosis of colorectal polyps in the general population, but no systematic studies are available for all forms of raised lesions in UC.

STUDY

All raised, polypoid and nonpolypoid, lesions found during consecutive surveillance colonoscopies with FICE for long-standing UC were included. In the primary prospective analysis, the Kudo classification was used to predict the histology by FICE. In a post hoc analysis, further endoscopic markers were also explored.

RESULTS

Two hundred and five lesions (mean size, 8 mm; range, 2 to 30 mm) from 59 patients (mean age, 56 y; range, 21 to 79 y) were analyzed. Twenty-three neoplastic (11%), 18 hyperplastic (9%), and 164 inflammatory (80%) lesions were found. Thirty-one lesions (15%), none of which were neoplastic, were unclassifiable according to Kudo. After logistic regression, a strong negative association resulted between endoscopic activity and neoplasia, whereas the presence of a fibrin cap was significantly associated with endoscopic activity. Using FICE, the sensitivity, specificity, and positive and negative likelihood ratios of the Kudo classification were 91%, 76%, 3.8, and 0.12, respectively. The corresponding values by adding the fibrin cap as a marker of inflammation were 91%, 93%, 13, and 0.10, respectively.

CONCLUSIONS

FICE can help to predict the histology of raised lesions in UC. A new classification of pit patterns, based on inflammatory markers, should be developed in the setting of UC to improve the diagnostic performance.

An adaptive-coherence light source for hyperspectral, topographic, and flow-contrast imaging

Colorectal cancer accounts for an estimated 8% of cancer deaths in the United States with a five-year survival rate of 55-75%. The early detection and removal of precancerous lesions is critical for reducing mortality, but subtle neoplastic growths, such as non-polypoid lesions, often go undetected during routine colonoscopy. Current approaches to flat or depressed lesion detection are ineffective due to the poor contrast of subtle features in white light endoscopy. Towards improving colorectal lesion contrast, we present an endoscopic light source with custom laser channels for multimodal color, topographic, and speckle contrast flow imaging. Three red-green-blue laser units, paired with laser speckle reducers, are coupled into endoscopic fiber optic light guides in a benchtop endoscope. Tissue phantom topography is reconstructed using alternating illumination of the laser units and a photometric stereo endoscopy algorithm. The contrast of flow regions is enhanced in an optical flow phantom using laser speckle contrast imaging. Further, the system retains the ability to offer white light and narrow band illumination modes with improved power efficiency, a reduced size, and longer lifetimes compared to conventional endoscopic arc lamp sources. This novel endoscopic light source design shows promise for increasing the detection of subtle lesions in routine colonoscopy screening.

Capsule endoscopy for patients with coeliac disease

Coeliac disease is an autoimmune mediated condition in response to gluten. A combination of innate and adaptive immune responses results in villous shortening in the small bowel (SB) that can be morphologically picked up on capsule endoscopy. It is the only imaging modality that can provide mucosal views of the entire SB, while histology is generally limited to the proximal SB. Radiological modalities are not designed to pick up changes in villous morphology. Areas covered: In this review, we provide a comprehensive analysis on the justified use of small bowel capsule endoscopy (SBCE) in the assessment of patients with coeliac disease; compare SBCE to histology, serology, and symptomatology; and provide an overview on automated quantitative analysis for the detection of coeliac disease. We also provide insight into future work on SBCE in relation to coeliac disease. Expert commentary: SBCE has opened up new avenues for the diagnosis and monitoring of patients with coeliac disease. However, larger studies with new and established coeliac disease patients and with greater emphasis on morphological features on SBCE are required to better define the role of SBCE in the setting of coeliac disease.

Gastric and duodenal polyps in familial adenomatous polyposis patients: Conventional endoscopy vs virtual chromoendoscopy (fujinon intelligent color enhancement) in dysplasia evaluation

AIM

To test the fujinon intelligent color enhancement (FICE) in identifying dysplastic or adenomatous polyps in familial adenomatous polyposis (FAP) patients.

METHODS

Seventy-six consecutive FAP patients, already treated by colectomy and members of sixty-five families, were enrolled. A FICE system for the upper gastro-intestinal tract with an electronic endoscope system and a standard duodenoscope (for side-viewing examination) were used by two expert examiners. Endoscopic resection was performed with diathermic loop for polyps ≥ 6 mm and with forceps for polyps < 6 mm. Formalin-fixed biopsy specimens were analyzed by two expert gastrointestinal pathologists blinded to size, location and number of FAP-associated fundic gland polyps.

RESULTS

Sixty-nine (90.8%) patients had gastric polyps (34 only in the corpus-fundus, 7 only in the antrum and 28 in the whole stomach) and 52 (68.4%) in duodenum (7 in the bulb, 35 in second/third duodenal portion, 10 both in the bulb and the second portion of duodenum). In the stomach fundus after FICE evaluation, 10 more polyps were removed from 10 patients for suspicious features of dysplasia or adenomas, but they were classified as cystic fundic gland after histology. In the antrum FICE identified more polyps than traditional endoscopy, showing a better tendency to identify adenomas and displastic areas. In the duodenum FICE added a significant advantage in identifying adenomas in the bulb and identified more polyps in the II/III portion.

CONCLUSION

FICE significantly increases adenoma detection rate in FAP patients but does not change any Spigelman stage and thus does not modify patient’s prognosis and treatment strategies.

Colonic Laterally Spreading Tumor Diagnosed as an Early Cancer and Treated with Endoscopic Mucosal Resection: A Case Report and Review of Literature

Laterally spreading tumors (LSTs) are generally defined as superficial lesions ≥10 mm in diameter that typically extend laterally rather than vertically along the colonic wall. Such lesions are now increasingly reported because of increased awareness and the introduction of chromo and magnifying colonoscopy. Although the clinicopathological characteristics and the efficacy of endoscopic management of LSTs have been defined in Japanese cohorts, reports from the Middle East are lacking where surgical resection is the mainstay of treatment. We report a case with an LST about 20 cm from anal verge removed by endoscopic mucosal resection. After histopathological evaluation of the removed specimen, we categorized the patient as having high risk early colon cancer. The intensive follow-up as an additional treatment strategy was chosen for the patient. This review addresses the management of early carcinoma in colorectal polyp with reference to proper preoperative assessment, treatment selection with special attention to role of biomarkers, the need for additional treatment on the basis of the presence of risk factors and endoscopic follow-up after treatment.

Sensitivity and Specificity of Fractal Analysis to Distinguish Between Healthy and Pathologic Rectal Mucosa Microvasculature Seen During Colonoscopy

PURPOSE

Conventional endoscopy is limited by human capability to recognize and to differentiate pathology. Fractal analysis of blood vessels has been used in other organs, such as the retina, but never before to supplement colonoscopy. The aim of this study was to assess whether it is possible to differentiate between healthy and pathologic rectal mucosa using fractal analysis of the mucosal microvascular architecture seen during colonoscopic examination (Supplemental Digital Content 1, http://links.lww.com/SLE/A145).

METHODS

A total of 300 consecutive patients, 133 females and 167 males with a mean age of 49.1 (±11.3) years, undergoing endoscopy were included in the prospective cohort study. Colonoscopy of the sigmorectal region was performed, and then analyzed with computer-assisted image fractal analysis.

RESULTS

Fractal analysis of mucosal vasculature allowed for differentiation between healthy and pathologic rectal mucosa, as well as different pathologies (P<0.0001). The sensitivity of fractal analysis to diagnose rectal neoplasia was 92.8% to 96.4%, while the specificity was 91.9% to 98.5% depending on the fractal parameter. The sensitivity of fractal analysis to diagnose rectal colitis was 84.2% to 92.1%, while the specificity was 95.0% to 96.0%, depending on the fractal parameter.

CONCLUSIONS

Computer-assisted fractal analysis allows for differentiation between healthy and pathologic rectal mucosa, as well as between different mucosal pathologies, seen during colonoscopy. Fractal analysis improves the sensitivity and specificity of colonoscopy to aid in the diagnosis of neoplasia or colitis, and should be included in the screening and surveillance of these pathologies.

Large Colorectal Lesions: Evaluation and Management

In the last years, a distinctive interest has been raised on large polypoid and non-polypoid colorectal tumors, and specially on flat neoplastic lesions ≥20 mm tending to grow laterally, the so called laterally spreading tumors (LST). Real or virtual chromoendoscopy, endoscopic ultrasound or magnetic resonance should be considered for the estimation of submucosal invasion of these neoplasms. Lesions suitable for endoscopic resection are those confined to the mucosa or selected cases with submucosal invasion ≤1000 μm. Polypectomy or endoscopic mucosal resection remain a first-line therapy for large colorectal neoplasms, whereas endoscopic submucosal dissection in high-volume centers or surgery should be considered for large LSTs for which en bloc resection is mandatory.

Observer agreement for diagnosis of colorectal lesions with analysis of the vascular pattern by image-enhanced endoscopy

BACKGROUND/AIMS

Image-enhanced endoscopy (IEE) can differentiate neoplastic from non-neoplastic colorectal lesions through indirect analysis of pit patterns and microvascular architecture. We evaluated the accuracy of Flexible Spectral Imaging Color Enhancement (FICE) in differentiating neoplastic from non-neoplastic lesions and observer agreement in the analysis of capillary pattern of colorectal lesions.

METHODS

A prospective double-blind trial was conducted in two referral endoscopy centers. Vascular pattern was analyzed by IEE with magnification. Lesions were divided into two groups and examined separately by two experts. Examiners, blinded to each other's interpretations, switched groups and the lesions were reviewed. After 60 days, lesions were reevaluated.

RESULTS

In total, 76 patients were referred to colonoscopy for colon cancer screening. Of 100 colorectal lesions, 88 were neoplastic (73 tubular adenomas, 10 tubulovillous adenomas, 1 villous adenoma, 2 serrated adenomas, 2 adenocarcinomas) and 12 were non-neoplastic (hyperplastic polyps). Mean diameter of the lesions was 6.7 mm. Examiners 1 and 2 had 95 % accuracy. The interobserver kappa coefficient was 0.80 and the intraobserver kappa coefficient was 0.88 for examiner 1 and 0.73 for examiner 2.

CONCLUSION

IEE with magnification is effective for real-time predictive histological diagnosis of colorectal lesions, with inter- and intraobserver agreement ranging from good to excellent.

Tools for polyp histology prediction

Although removal of adenomatous polyps has been shown to decrease the risk of colon cancer, distal hyperplastic polyps are thought to not have malignant potential. Most polyps detected during colonoscopy are diminutive (≤ 5 mm) and rarely harbor advanced histology, such as high-grade dysplasia or cancer. Therefore, predicting histology in real-time during colonoscopy can potentially decrease the enormous expenditure that ensues from universal histopathologic evaluation of polyps, and several novel imaging technologies have been developed and tested over the past decade for this purpose. Of these different technologies, electronic chromoendoscopy seems to strike a fair balance between accuracy, feasibility, and cost.

Colonic polyps: Is it useful to characterize them with advanced endoscopy?

There have been major developments in endoscopic imaging techniques in recent years. Endoscopes with high definition and magnification can provide high quality images that allow for the histological estimation of lesions in vivo and in situ when combined with ancillary enhancement techniques such as chromoendoscopy (CE) and virtual CE (narrow band imaging fujinon intelligent chromoendoscopy, or i-Scan). Despite the enormous potential for these advanced techniques, their value and feasibility in the clinic are still doubted, particularly in cases of colonic polyps that are slated for removal, where in vivo characterization may be deemed unnecessary. However, there are several advantages offered by such advanced endoscopic imaging. CE with or without magnification demonstrates highly accurate histology and invasion depth prediction, and virtual CE is a feasible and less cumbersome alternative to CE in terms of histological estimation, though not sufficiently accurate for depth invasion prediction. Furthermore, the supplementary information provided by advanced imaging systems can assist the endoscopist in the selection of a strategic approach, such as in deciding whether a colonic lesion should be resected, left in situ, or requires more intensive surgical treatment. Lastly, advanced high-resolution imaging techniques may be more cost effective, such that histopathology of low-risk lesions following resection can be eliminated. The results of these evaluations and comparisons with traditional CE are presented and discussed. Taken together, the benefits provided by these advanced capabilities justify their development, and advocates their use for the treatment and management of colonic polyps.

Advances in colonoscopy

Colonoscopy with polypectomy has been established as the major prevention and detection strategy for colorectal cancer for over a decade. Over this period advances in colonoscopic imaging, polyp detection, prediction of histopathology and polypectomy techniques have all been seen; however, the true magnitude of the limitations of colonoscopy has only recently been widely recognized. The rate and location of missed or interval cancers after complete colonoscopy appears to be influenced by the operator-dependency of colonoscopy and failure of conventional practices to detect and treat adenomatous, and possibly more importantly, non-adenomatous colorectal cancer precursors. Consequently, studies that expand our understanding of these factors and advances that aim to improve colonoscopy, polypectomy, and cancer protection are of critical importance.

Prevention of colonic spasm using L-menthol in colonoscopic examination

PURPOSE

The detailed efficacy of intraluminal L-menthol for preventing colonic spasm is not known. The aim of this study was to evaluate the effectiveness of L-menthol in preventing colonic spasm during colonoscopy.

METHODS

We analyzed 65 patients (mean age: 71.7 years; 49 men and 16 women) who were administered 0.8% L-menthol (MINCLEA, Nihon Seiyaku, Tokyo, Japan) intraluminally for severe colonic spasm during colonoscopic examination at Kyoto Prefectural University of Medicine between February 2012 and May 2013. The efficacy of L-menthol was defined as the absence of colonic spasm during a period of 30 s, and its effect was evaluated at 30 s, 1 min, and 5 min after administration. Additionally, various characteristics of these patients were analyzed. Twenty-seven patients with severe colonic spasm were administered intraluminal water and assessed as controls.

RESULTS

L-Menthol was effective in preventing colonic spasms in 60.0%, 70.8%, and 46.5% of patients at 30 s, 1 min, and 5 min, respectively. In contrast, water was effective in 22.2%, 29.6%, and 48.1% of patients at 30 s, 1 min, and 5 min, respectively. There was a significant difference about the efficacy at 30 s and 1 min between L-menthol and water (P = 0.0009, P = 0.0006).

CONCLUSIONS

L-Menthol (0.8%) was effective in preventing colonic spasm during colonoscopic examination.

Ability of a novel blue laser imaging system for the diagnosis of colorectal polyps

BACKGROUND

A new endoscope system with a laser light source, blue laser imaging (BLI), has been developed by Fujifilm that allows for narrow-band light observation. The aim of the present study was to evaluate the utility of BLI for the diagnosis of colorectal polyps.

METHODS

We retrospectively analyzed 314 colorectal polyps that were examined with BLI observation at Kyoto Prefectural University of Medicine between September 2011 and January 2013. The surface and vascular patterns of polyps detected by published narrow-band imaging magnification: Hiroshima classification were used. Correlations were determined between the classifications and the histopathological diagnoses. Additionally, the ability of BLI without magnification to differentiate between neoplastic or non-neoplastic polyps was analyzed.

RESULTS

A total of 41 hyperplastic polyps, 168 adenomas, 80 intramucosal cancer, 11 shallowly invaded submucosal cancer, and 14 deeply invaded submucosal cancer were analyzed.Hyperplastic polyp was observed in 100% of Type A lesions (39 lesions), adenoma was observed in 89.3% of Type B lesions (159 lesions), intramucosal cancer and shallowly invaded submucosal cancer was observed in 69.6% of Type C1 (92 lesions) and in 84.6% of Type C2 (13 lesions), and deeply invaded submucosal cancer was observed in 81.8% of Type C3 lesions (11 lesions). The overall diagnostic accuracy of BLI with magnification was 84.3%. Additionally, the diagnostic accuracy of BLI without magnification for differentiating between neoplastic and non-neoplastic polyps <10 mm in diameter was 95.2%, which was greater than that of white light (83.2%).

CONCLUSION

BLI was useful for the diagnosis of colorectal polyps.

The ability of a novel blue laser imaging system for the diagnosis of invasion depth of colorectal neoplasms

BACKGROUND

Fujifilm has developed a novel endoscope system with two kinds of lasers that enables us to allow narrow-band light observation with blue laser imaging (BLI). The aim of this study was to evaluate BLI magnification in comparison with narrow-band imaging (NBI) magnification for the diagnosis of colorectal neoplasms.

METHODS

This was a multicenter open study. A total of 104 colorectal neoplasms were examined with BLI and NBI magnifications in Kyoto Prefectural University of Medicine and Fukuoka University Chikushi Hospital. Vascular and surface patterns of tumors under BLI magnification were compared with those under NBI magnification, using a published NBI classification. The main outcome was the correlation between the NBI classification diagnosed by BLI or NBI magnification and the histopathological analyses.

RESULTS

Sixty-two cases of adenoma, 34 cases of intramucosal cancer and shallowly invaded submucosal cancer, and eight cases of deeply invaded submucosal cancer were diagnosed. The diagnostic accuracy of BLI magnification in the NBI classification was 74.0 % (77/104), similar to that of NBI magnification (77.8 %). The consistency rate between BLI and NBI magnification in the NBI classification was 74.0 %. Concerning image evaluation, the interobserver variability of two expert endoscopists (N.Y. and T.H.) in BLI magnification was κ = 0.863. On the other hand, the intraobserver variability of the two endoscopists was κ = 0.893 (N.Y.) and 0.851 (T.H.).

CONCLUSIONS

BLI magnification by laser source could predict histopathological diagnosis and invasion depth of colorectal neoplasms. The diagnostic effectiveness of this method was similar to that of NBI magnification.

Diagnostic performance of narrowed spectrum endoscopy, autofluorescence imaging, and confocal laser endomicroscopy for optical diagnosis of colonic polyps: a meta-analysis

BACKGROUND

Novel endoscopic technologies could allow optical diagnosis and resection of colonic polyps without histopathological testing. Our aim was to establish the sensitivity, specificity, and real-time negative predictive value of three types of narrowed spectrum endoscopy (narrow-band imaging [NBI], image-enhanced endoscopy [i-scan], and Fujinon intelligent chromoendoscopy [FICE]), confocal laser endomicroscopy (CLE), and autofluorescence imaging for differentiation between neoplastic and non-neoplastic colonic lesions.

METHODS

We identified relevant studies through a search of Medline, Embase, PubMed, and the Cochrane Library. Clinical trials and observational studies were eligible for inclusion when the diagnostic performance of NBI, i-scan, FICE, autofluorescence imaging, or CLE had been assessed for differentiation, with histopathology as the reference standard, and for which a 2 × 2 contingency table of lesion diagnosis could be constructed. We did a random-effects bivariate meta-analysis using a non-linear mixed model approach to calculate summary estimates of sensitivity and specificity, and plotted estimates in a summary receiver-operating characteristic curve.

FINDINGS

We included 91 studies in our analysis: 56 were of NBI, ten of i-scan, 14 of FICE, 11 of CLE, and 11 of autofluorescence imaging (more than one of the investigated modalities assessed in eight studies). For NBI, overall sensitivity was 91·0% (95% CI 88·6-93·0), specificity 85·6% (81·3-89·0), and real-time negative predictive value 82·5% (75·4-87·9). For i-scan, overall sensitivity was 89·3% (83·3-93·3), specificity 88·2% (80·3-93·2), and real-time negative predictive value 86·5% (78·0-92·1). For FICE, overall sensitivity was 91·8% (87·1-94·9), specificity 83·5% (77·2-88·3), and real-time negative predictive value 83·7% (77·5-88·4). For autofluorescence imaging, overall sensitivity was 86·7% (79·5-91·6), specificity 65·9% (50·9-78·2), and real-time negative predictive value 81·5% (54·0-94·3). For CLE, overall sensitivity was 93·3% (88·4-96·2), specificity 89·9% (81·8-94·6), and real-time negative predictive value 94·8% (86·6-98·1).

INTERPRETATION

All endoscopic imaging techniques other than autofluorescence imaging could be used by appropriately trained endoscopists to make a reliable optical diagnosis for colonic lesions in daily practice. Further research should be focused on whether training could help to improve negative predictive values.

FUNDING

None.

Image-enhanced endoscopy for diagnosis of colorectal tumors in view of endoscopic treatment

Recently, image-enhanced endoscopy (IEE) has been used to diagnose gastrointestinal tumors. This method is a change from conventional white-light (WL) endoscopy without dyeing solution, requiring only the push of a button. In IEE, there are many advantages in diagnosis of neoplastic tumors, evaluation of invasion depth for cancerous lesions, and detection of neoplastic lesions. In narrow band imaging (NBI) systems (Olympus Medical Co., Tokyo, Japan), optical filters that allow narrow-band light to pass at wavelengths of 415 and 540 nm are used. Mucosal surface blood vessels are seen most clearly at 415 nm, which is the wavelength that corresponds to the hemoglobin absorption band, while vessels in the deep layer of the mucosa can be detected at 540 nm. Thus, NBI also can detect pit-like structures named surface pattern. The flexible spectral imaging color enhancement (FICE) system (Fujifilm Medical Co., Tokyo, Japan) is also an IEE but different to NBI. FICE depends on the use of spectral-estimation technology to reconstruct images at different wavelengths based on WL images. FICE can enhance vascular and surface patterns. The autofluorescence imaging (AFI) video endoscope system (Olympus Medical Co., Tokyo, Japan) is a new illumination method that uses the difference in intensity of autofluorescence between the normal area and neoplastic lesions. AFI light comprises a blue light for emitting and a green light for hemoglobin absorption. The aim of this review is to highlight the efficacy of IEE for diagnosis of colorectal tumors for endoscopic treatment.

Digital chromoendoscopy for diagnosis of diminutive colorectal lesions

Introduction. To compare the accuracy of digital and real-time chromoendoscopy for the differential diagnosis of diminutive (<5 mm) neoplastic and nonneoplastic colorectal lesions. Materials and Methods. This is a prospective randomized study comparing the Fujinon intelligent color enhancement (FICE) system (65 patients/95 lesions) and indigo carmine (69 patients/120 lesions) in the analysis of capillary meshwork and pit pattern, respectively. All lesions were less than 5 mm in diameter, and magnification was used in both groups. Histopathology was the gold standard examination. Results. Of 215 colorectal lesions, 153 (71.2%) were adenomas, and 62 were hyperplastic polyps (28.8%). Morphological analysis revealed 132 (61.4%) superficial lesions, with 7 (3.3%) depressed lesions, and 83 (38.6%) protruding lesions. Vascular meshwork analysis using FICE and magnification resulted in 91.7% sensitivity, 95.7% specificity, and 92.6% accuracy in differentiating neoplastic from nonneoplastic lesions. Pit pattern analysis with indigo carmine and magnification showed 96.5% sensitivity, 88.2% specificity, and 94.2% accuracy for the same purpose. Conclusion. Both magnifying virtual chromoendoscopy and indigo carmine chromoendoscopy showed high accuracy in the histopathological diagnosis of colorectal lesions less than 5 mm in diameter.