Probe-Based confocal laser endomicroscopy shown not to be as effective as other advanced imaging techniques for the differentiation of colorectal lesions

Reference: Kuiper, T., et al., Feasibility and Accuracy of Confocal Endomicroscopy in Comparison With Narrow-Band Imaging and Chromoendoscopy for the Differentiation of Colorectal Lesions. Am J Gastroenterol, 2012. 


A study out of the Netherlands on the effectability of various advanced imaging techniques for the differentiation of colo-rectal lesions.

Brief Summary: The main objective of this study was to compare the accuracy of several advanced imaging techniques for the differentiation of colon cancer. Particularly, the advanced imagine techniques compared were Chromoendoscopy (CE), Narrow Band Imaging (NBI), and probe-based confoscal laser endomicscropy (pCLE).  Specifically, two different variations of the Narrow Band Imaging were analyzed - one that uses the Kudo pit pattern (NBI-Kudo) and another that used the vasculor pattern intensity for differential diagnosis (NBI-VPI).  

Results: The authors found that the pCLE imaging technique was significantly less effective than any of the other advanced imaging techniques (CE, NBI-Kudo, NBI-VPI). Specifically, the authors later showed that the CE and NBI-Kudo methods were the two best advanced imagine techniques.  

Implications for Practice: For the purpose of advanced imaging, Gastroenterologists can not yet place a high degree of confidence on the probe-based confoscal laser endomicscropy technique  for the differential diagnosis of colon lesions. Rather, they should place a greater priority on the Chromoendoscopy and the Narrow Band Imaging with the Kudo accessment advanced imaging techniques for the purpose of differentiating colon lesions.  

Brief Discussion: One of the advantages of the pCLE method is that it can provide a direct diagnosis of individual cells without the need for any biopsy - thus reducing the total time and cost of a colonoscopy considerably. However, in order to use the pCLE method, it needs to show a greater degree of effectiveness than other advanced imagine techniques, and this study shows that it does not.  

It was interesting to note that the authors found that the accuracy of the pCLE method increased for the high quality videos vs. the lower quality videos.  If more attention could possibly be put towards getting higher quality videos, then this could significantly enhance differential diagnostic accuracy.       

Brief Commentary on Statistics and Study Design: Overall, the statistical design of the experiment looked good.  The statistician decided to use the McNamara's test in order to compare the contingency tables derived from the various imagine techniques, which is the correct test to use for this.  One can obviously not assume that the evaluative results from the various imaging techniques are independent, so the McNamara's test is the correct one to use.   

It would have been interesting to see if the ratings from the different imaging techniques were different depending on various patient characteristics. For instance, would a certain test be more effective than another test based on the age of the patient? Common sense would probably say no, but it would still be interesting to see.