Reply to Rostami et al.

We thank Rostami et al. for their interest in our paper [1]. In this feasibility study, narrow band imaging with optical magnification (NBI-Z) was clearly able to discern the villous morphology in keeping with the Marsh 3 classification.

It must be stressed that the study was performed on 21 patients suspected of having celiac disease (6 with anemia, 6 abdominal pain, 5 chronic diarrhoea, 3 bloating, and 1 with positive tissue transglutaminase [tTg]), amongst whom only three patients demonstrated the disease. We would also like to point out that all three patients were identified using the NBI-Z technology. Amongst these three, only one patient demonstrated the typical appearances on white light endoscopy as described in the critique of Rostami et al. and by other authors. NBI-Z was hence valuable in detecting two additional patients. We would therefore beg to differ with Rostami and colleagues that the Marsh 3 patients are a nonchallenging subgroup.

Furthermore, we required three NBI-naive endoscopists to grade the villous morphology after a short learning session, and were able to demonstrate relatively high accuracies (> 95 % for all three assessors) and good inter- and intraobserver agreement (κ > 0.75). This indicates that the simplified classification was not only easily learnt but also reproducible.

We agree however that this technology is unable to distinguish patients with Marsh 1 and 2 grade disease. This is mainly because of the level of magnification achieved (× 80 – 115) and hence is a drawback. Novel techniques such as endocytoscopy and confocal endomicroscopy, with magnification levels of up to × 1000 may enable this differentiation although there have been conflicting results in this regard [2] [3] [4].

We would therefore like to point out that NBI-Z could potentially aid the endoscopist in case-finding during routine endoscopy (as shown in our study), and the technique may also be useful for performing targeted biopsies especially in patients presenting with patchy villous atrophy. This could address the concern of Rostami et al. with regard to the frequent inadequacy of biopsy sampling by endoscopists.

References

• 1 Singh R, Nind G, Tucker G et al. Narrow-band imaging in the evaluation of villous morphology: a feasibility study assessing a simplified classification and observer agreement.  Endoscopy. 2010;  42 889-894
• 2 Leong R W, Nguyen N G, Meredith C G et al. In vivo confocal endomicroscopy in the diagnosis and evaluation of celiac disease.  Gastroenterology. 2008;  135 1870-1876
• 3 Pohl H, Rosch T, Tanczos B et al. Endocytoscopy for the detection of microstructural features in adult patients with celiac sprue: a prospective, blinded endocytoscopy – conventional histology correlation study.  Gastrointest Endosc. 2009;  70 933-941
• 4 Singh R, Raju D, Chen Yi Mei S L et al. Real-time histology with the endocytoscope.  World J Gastroenterol. 2010;  16 5016-5019