Differences of image enhancement in image-enhanced endoscopy: narrow band imaging versus flexible spectral imaging color enhancement

Development of Image-enhanced Endoscopy of the Gastrointestinal Tract: A Review of History and Current Evidences

Endoscopy imaging of the gastrointestinal (GI) tract has evolved tremendously over the last few decades. Key milestones in the development of endoscopy imaging include the use of various dyes for chromoendoscopy, the application of optical magnification in endoscopy, the introduction of high-definition image capturing and display technology and the application of altered illuminating light to achieve vascular and surface enhancement. Aims of this review paper are to summarize the development and evolution of modern endoscopy imaging and in particular, imaged-enhanced endoscopy (IEE), to promote appropriate usage, and to guide future development of good endoscopy practice. A search of PubMed database was performed to identify articles related to IEE of the GI tract. Where appropriate, landmark trials and high-quality meta-analyses and systematic reviews were used in the discussion. In this review, the developments and evolutions in endoscopy imaging and in particular, IEE, were summarized into discernible eras and the literature evidence with regard to the strengths and weaknesses in term of their detection and characterization capability in each of these eras were discussed. It is in the authors' opinion that IEE is capable of fairly good detection and accurate characterization of various GI lesions but such benefits may not be readily reaped by those who are new in the field of luminal endoscopy. Exposure and training in making confident diagnoses using these endoscopy imaging technologies are required in tandem with these new developments in order to fully embrace and adopt the benefits.

Comparison of Narrow Band Imaging and Fujinon Intelligent Color Enhancement in Predicting Small Colorectal Polyp Histology

BACKGROUND

There are limited data on the performance of narrow band imaging (NBI) and Fujinon intelligent color enhancement (FICE) for differentiating polyp histologies.

AIMS

The aim of this study was to compare the diagnostic performances of NBI and FICE in differentiating neoplastic from non-neoplastic colorectal polyps <10 mm during screening colonoscopy.

METHODS

A total of 955 average-risk adults undergoing screening colonoscopies were randomly allocated to NBI or FICE groups. Four board-certified staff endoscopists without prior experience using NBI or FICE participated. The main outcomes of this study were overall accuracy, sensitivity, and specificity of FICE and NBI in identifying neoplastic polyps.

RESULTS

There was no significant difference in the number of subjects with adenoma between the NBI (143/475, 30.1 %) and FICE groups (139/480, 29.0 %) (after excluding adenoma ≥1 cm) (P > 0.05). The overall accuracy of NBI was 81.0 %, compared with 81.4 % for FICE (P = 0.867). The overall sensitivity and specificity of NBI and FICE were 84.6 and 78.0 % (P = 0.054); 75.1 and 86.5 % (P = 0.009), respectively. For polyps measuring ≤5 mm, the accuracy was 79.4 % for NBI and 80.1 % for FICE (P = 0.835; sensitivity 81.9 vs. 74.5 %, P = 0.064; specificity 75.7 vs. 88.4 %, P = 0.006).

CONCLUSIONS

The overall accuracy of NBI and FICE was similar for differentiating small polyp histologies during screening colonoscopy. However, better results should be achieved before using NBI or FICE as real-time optical biopsy of colorectal polyps in screening colonoscopy.

Evaluation of a new image-enhanced endoscopic technology using band-limited light for detection of esophageal squamous cell carcinoma

BACKGROUND

The aim of the present study was to evaluate the clinical utility of a new image-enhanced endoscopy (IEE) technology called optical enhancement imaging (OEI-1, -2, -3) by quantitatively evaluating diagnostic performance in superficial esophageal squamous cell carcinoma (SCC) in order to facilitate detection and characterization of gastrointestinal tumors.

PATIENTS AND METHODS

The study involved 10 esophageal SCC resected endoscopically at our hospital. Ex vivo observation of the boundary area between normal and SCC was done using each mode (white light image [WLI], OEI-1, OEI-2, and OEI-3) with and without magnification. The additional effect of OEI on WLI was evaluated by calculating the color difference (expressed as ΔE94 ) between SCC and normal epithelium, and that between the intraepithelial papillary capillary loop (IPCL) and inter-vascular background coloration (IVBC).

RESULTS

Mean ΔE94 values between SCC and normal epithelium for WLI, OEI-1, OEI-2, and OEI-3 were 9.37 ± 4.64, 13.82 ± 4.46,13.26 ± 4.73, and 16.44 ± 4.83, respectively; the corresponding values between IPCL and IVBC were 17.57 ± 10.17, 29.32 ± 9.95, 25.41 ± 11.72, and 23.71 ± 11.58, respectively. Compared with WLI, all OEI exhibited significant additional effect on ΔE94 . Furthermore, we found significant additional effect of OEI-3 in observing SCC and normal epithelium, and of OEI-1 in observing IPCL and IVBC, compared with other OEI.

CONCLUSION

These results suggest that OEI improves endoscopic detection and characterization of esophageal SCC compared with WLI. Moreover, the data indicate that OEI-3 is useful for detection and OEI-1 is useful for characterization of esophageal SCC.

A randomized crossover open trial of the adenoma miss rate for narrow band imaging (NBI) versus flexible spectral imaging color enhancement (FICE)

PURPOSE

Narrow band imaging (NBI) and flexible spectral imaging color enhancement (FICE) allow improved contrasted evaluation of the mucosal surface. However, no study has compared the utility of these two modalities. Therefore, the aim of this study was to compare the adenoma miss rate (AMR) between NBI and FICE.

METHODS

A total of 55 patients (38 men, 17 women) were enrolled in this study. Patients were randomly assigned to the NBI-FICE group (NBI followed by FICE) or the FICE-NBI group (FICE followed by NBI). NBI and FICE total colonic observations were tandemly performed for each patient during the scope withdrawal with white light following cecal intubation. All detected polyps with the NBI or FICE observation were categorized into three groups according to the size and number of polyps missed.

RESULTS

Twenty-nine patients were assigned to the NBI-FICE group, and 26 patients were assigned to the FICE-NBI group. There was no significant difference in the overall AMR when comparing the image-enhanced endoscopy technologies (17.9 % for NBI, 26 % for FICE, p = 0.159). AMR was lower for NBI than for FICE for adenomas <5 mm in diameter (5.7 % for NBI, 12.6 % for FICE, p = 0.036). AMR was not significantly different when comparing NBI and FICE for lesions 5 to 10 mm (p = 0.967) or for lesions ≥10 mm (p = 0.269).

CONCLUSIONS

This study demonstrated that overall AMR was not different when comparing NBI and FICE.

Advanced endoscopic imaging for Barrett's Esophagus: current options and future directions

Barrett's esophagus is the precursor to esophageal adenocarcinoma, one of the most rapidly increasing cancers in the United States. Given the poor prognosis of late-stage adenocarcinoma, endoscopic surveillance is recommended for subjects with Barrett's esophagus to detect early neoplasia. Current guidelines recommend "random" four-quadrant biopsies taken every 1-2 cm throughout the Barrett's segment. However, this only samples a minority of epithelium and has been shown to miss areas of endoscopically- inapparent neoplasia (high grade dysplasia or cancer). Recent efforts have focused on developing novel diagnostic imaging technologies to detect the subtle epithelial changes associated with dysplasia and neoplasia in Barrett's esophagus. Some of these modalities serve as "red flag" technologies designed to detect areas of abnormality within large surface areas. Other technologies serve to characterize areas of visible abnormality, offering a higher spatial resolution to confirm/exclude the presence of neoplasia. This review summarizes several available and evolving imaging technologies used in the endoscopic diagnosis and surveillance of Barrett's associated neoplasia.