Optical Microangiography: High-Definition Magnification Colonoscopy with Narrow Band Imaging (NBI) for Visualizing Mucosal Capillaries and Red Blood Cells in the Large Intestine

Prospective study of diagnostic yields of flexible spectral imaging color enhancement installed in colon capsule endoscopy for colorectal polyps and tumors

BACKGROUND AND AIMS

We prospectively determined the efficacy of flexible spectral imaging color enhancement (FICE) used with second-generation colon capsule endoscopy (CCE) for colorectal polyps and tumors (CRTs).

METHODS

This study included optical colonoscopy within 4 months after CCE. Two colonoscopists independently reviewed CCE using white-light images (CCE-WL) and CCE using FICE images (CCE-FICE), respectively. Based on colonoscopic findings as the criterion standard, the diagnostic accuracy for CRTs was compared between CCE-WL and CCE-FICE.

RESULTS

Of 89 enrolled patients (65 men and 24 women; 75 with CRTs including 36 with serrated lesions, 63 with adenomas, and 9 with adenocarcinomas), the per-patient detectability of CCE-FICE for the representative CRTs was significantly higher than that of CCE-WL: overall CRTs (CCE-WL, 79%; CCE-FICE, 88%; P = .0001), 6- to 9-mm CRTs (CCE-WL, 63%; CCE-FICE, 94%; P = .0055), and ≥6-mm CRTs (CCE-WL, 78%; CCE-FICE, 93%; P = .0159). The per-lesion sensitivity of CCE-FICE was significantly higher than that of CCE-WL for CRTs: overall (CCE-WL, 61%; CCE-FICE, 79%; P < .0001), <6 mm (CCE-WL, 53%; CCE-FICE, 69%; P < .0001), 6- to 9-mm CRTs (CCE-WL, 65%; CCE-FICE, 93%; P = .0007), slightly elevated CRTs (CCE-WL, 53%; CCE-FICE, 75%; P < .0001), tubular adenomas (CCE-WL, 61%; CCE-FICE, 79%; P < .0001), and serrated polyps (CCE-WL, 57%; CCE-FICE, 74%; P = .0022). Both modes detected all adenocarcinomas. No significant differences were found between CCE-WL and CCE-FICE of the per-lesion sensitivity for ≥10-mm CRTs (CCE-WL, 81%; CCE-FICE, 94%; P = .1138) or protruding CRTs (CCE-WL, 77%; CCE-FICE, 86%; P = .0614). Kappa coefficients for overall CRTs for CCE-WL and CCE-FICE were .66 and .64, respectively, which indicated substantial agreement.

CONCLUSIONS

CCE-FICE improved the detection rates for all CRTs except adenocarcinomas, ≥10-mm polyps, and protruding polyps when compared with CCE-WL. (Clinical trial registration number: UMIN 000021125.).

Idiopathic myointimal hyperplasia of mesenteric veins depicted by barium enema examination, and conventional and magnifying colonoscopy

A 71-year-old man was admitted to our institution complaining of abdominal pain and constipation. Barium enema examination revealed narrowing, cobble stoning, and longitudinal ulcerations in the sigmoid colon and upper rectum. Conventional colonoscopy, magnifying narrow-band imaging endoscopy, and magnifying chromoendoscopy revealed edematous mucosa, longitudinal ulcerations with luminal narrowing, and multiple pseudopolyps. The histologic examination of the biopsy specimens showed thick-walled (arterialized) capillaries and subendothelial fibrin deposits in the mucosa and submucosa. Based on a preoperative diagnosis of idiopathic myointimal hyperplasia of mesenteric veins (IMHMV), he underwent a laparoscopic resection of the sigmoid colon and upper rectum. The histologic examination of the resected specimens showed marked proliferation of venous walls with marked myointimal thickening and luminal occlusion from the submucosa to the mesentery throughout the entire resected tissue section. The final diagnosis was IMHMV.

Endoscopic microanatomy of the normal gastrointestinal mucosa with narrow band technology and magnification

The development of high-definition endoscopes with optical zoom, along with the use of the digital chromoendoscopy and staining, has given endoscopists the possibility to study the microanatomy of the gastrointestinal mucosa in vivo. The recognition of the changes in the microstructure of the surface and microvascular architecture such as those that occur in neoplastic lesions allow us to characterize these lesions in order to decide on the best course of clinical action. The current greater availability of endoscopes with optical zoom in western countries has allowed the use of this technology in routine clinical practice to spread. In this article we review the basic concepts of magnifying endoscopy and the normal endoscopic microanatomy of the oesophageal, gastric, duodenal, ileal and colonic mucosa.

Usefulness of close observation with non-magnified blue laser imaging for determining cold polypectomy indications

PURPOSE

To examine the usefulness of non-magnified close observation with blue laser imaging (BLI) using a colonoscope with close observation capability in determining indications for cold polypectomy.

METHODS

We conducted an image evaluation study on 100 consecutive colorectal lesions of 10 mm or less which were observed endoscopically without magnification using BLI mode prior to treatment. Two experts and two non-experts reviewed the images using the Japan NBI expert team (JNET) classification and the diagnostic accuracy was analyzed.

RESULTS

The final pathological diagnoses of the 100 lesions were hyperplastic/sessile serrated polyp (HP/SSP), low grade dysplasia (LGD), high grade dysplasia (HGD) and deep submucosal invasive cancer (dSM), respectively, in 12, 79, 9 and 0 lesions. When JNET classification type 1 corresponds to HP/SSP; 2A to LGD; 2B to HGD; and 3 to dSM; the overall diagnostic accuracy was 84.3%. Accuracy was 90.5% for experts and 78.0% for non-experts. High confidence rate was 67.5% for experts and 48.0% for non-experts. In diagnostic accuracy for HGD, the sensitivity, specificity, PPV and NPV were, respectively, 77.8%, 98.9%, 87.5% and 97.8% for experts; and 66.6%, 92.3%, 46.2% and 96.6% for non-experts.

CONCLUSIONS

The diagnostic accuracy of unmagnified close observation with BLI using a colonoscope with close observation capability is similar to that reported for magnifying endoscopy and is useful in predicting the histological diagnosis of colorectal polyps of 10 mm or less although the effectiveness may be limited for non-experts. This modality is a potentially useful tool in deciding indications for cold polypectomy.

Differential diagnosis of colorectal polyps with narrow band imaging colonoscopy without magnification

BACKGROUND/AIMS

Narrow band imaging (NBI) endoscopy can be used for gross differentiation between the types of colonic polyps. This study was conducted as a retrospective study for estimation of the interobserver and intra-observer agreement of the pit pattern of the mucosal surface and the accuracy of histology prediction.

METHODS

A total of 159 patients underwent complete colonoscopy and 219 polyps examined by NBI endoscopy without magnification were assessed. Interobserver and intra-observer agreement were calculated by investigators in each group for determination of the surface pattern and prediction of histology based on the modified Kudo's classification using intraclass correlation coefficient.

RESULTS

Interobserver agreement for the surface pit pattern and prediction of polyp type was 0.84 and 0.73 in experienced endoscopists, and 0.86 and 0.62 in trainees, respectively. Intra-observer agreement for the surface pit patterns and prediction of polyp type was 0.81, 0.83, 0.85, 0.83, 0.56, 0.84, 0.51, 0.83, and 0.71; and 0.71, 0.70, 0.82, 0.54, 0.72, 0.37, 0.51, 0.34, and 0.30, respectively. The diagnostic accuracy for prediction of polyp type was 69.4% for experienced endoscopists and 72.9% for trainees.

CONCLUSIONS

NBI endoscopy without magnification showed fairly good inter and intra-observer agreement for the pit pattern of the mucosal surface and the accuracy of histology prediction; however, it had some limitation for differentiation of colon polyp histologic type. Training and experience with NBI is needed for improvement of accuracy.

Blue-green endoscopy in a dog presenting chronic vomiting-regurgitation

A 2-year-old male Maremma sheepdog presenting with chronic vomiting-regurgitation was examined at the University Veterinary Teaching Hospital, Camerino University. An oesophagogastroscopy with a single blue + green (BG) filter restricting wavelengths from 400 to 550 nm was carried out. A conventional white light endoscopy showed a dilated oesophagus with mildly diffuse erythematous mucosa (more accentuated proximal to the cardia); some portions of the gastric mucosa were covered with fluids and appeared only slightly erythematous. A blue green endoscopy highlighted the oesophageal lesions in dark blue, which made them appear more clearly defined from the remaining mucosa. In the gastric antrum, a small, slightly darker blue roundish area was visible. This area did not show up under the white light endoscopy. A histopathological assessment of biopsy specimens from the distal oesophagus, antrum (including the area highlighted only by BG endoscopy) and gastric body showed chronic-active hyperplastic esophagitis and superficial squamous epithelial dysplasia, while gastric samples showed severe diffuse hyperaemic gastritis of the antrum and superficial diffuse atrophy of the gastric body. The authors believe that the use of a BG endoscopy could be useful in veterinary medicine to increase the diagnostic potential of endoscopic assessment in animals.