Advanced endosonographic diagnostic tools for discrimination of focal chronic pancreatitis and pancreatic carcinoma--elastography, contrast enhanced high mechanical index (CEHMI) and low mechanical index (CELMI) endosonography in direct comparison.

New tools have recently emerged that further improve the diagnostic performance of high-end endosonography. Whilst elastography has been available for a while, contrast-enhancing techniques are still very young with little experience existing in this field. The latest development is contrast enhanced low mechanical index endosonography (CELMI-EUS) which became commercially available at the beginning of 2010. This technique requires contrast-specific software whereas the pre-existing technique of contrast-enhanced high mechanical index endosonography (CEHMI-EUS) does not. The aim of this study was to compare these techniques in discriminating between focal chronic pancreatitis and pancreatic carcinoma. Included in the study were 58 patients with a pancreatic lesion (19 pancreatic cancer and 39 chronic pancreatitis) with a mean age of 60±15 years. All patients were examined by one investigator (MH). All methods were performed within one examination and the result of each technique was noted before using the next. The gold standard was pathology following surgery, endoscopic fine-needle puncture, or one-year follow-up when chronic pancreatitis was suspected. The consecutive results of specificity and sensitivity were 73.7% and 61.5% for B-mode endosonography; 94.7% and 33.4% for elastography; 84.2% and 76.9% for CELMI-EUS; and 89.5% and 92.3% for CEHMI-EUS. A combination of 3 of those methods could not improve on the result of CEHMI-EUS alone. This study shows that, despite the availability of new technologies, CEHMI-EUS is still the most reliable method for the differentiation of focal chronic pancreatitis and pancreatic carcinoma. However, understanding the advantages of the different methods might help to find the optimal indications for the use of the new techniques.