Peter R. Galle

Simultaneous confocal laser endomicroscopy and chromoendoscopy with topical cresyl violet

BACKGROUNDnConfocal laser endomicroscopy (CLE) has been shown to reliably predict histology during ongoing endoscopy. To unmask lesions for CLE, chromoendoscopy has been mandated. Usually fluorescein then serves as a contrast agent for CLE, but it does not allow direct nuclear visualization, must be injected, leads to a transient skin discoloration, and may have allergic side effects.nnnOBJECTIVEnTo establish a single topical dye, cresyl violet (CV), for simultaneous chromoendoscopy and in vivo CLE of the lower GI tract.nnnDESIGNnAnimal preclinical study, prospective clinical trial.nnnSETTINGnMainz University Clinic (tertiary care center). PATIENTS, METHODS, AND INTERVENTIONS: To establish the staining characteristics and optimal concentration of CV, the ileum and colon of 7 BL6 mice were stained with CV (0.1%-2%), and in vivo confocal imaging was performed with FIVE1. In a subsequent clinical trial, 67 sites in 36 patients were topically stained with CV 0.13%, and subsurface serial images were generated at different depths with an endomicroscope.nnnMAIN OUTCOME MEASUREMENTSnPrediction of histology according to the Mainz confocal classification and nuclear visualization with topical CV.nnnRESULTSnEndomicroscopy with topical CV yielded (sub-)cellular details of normal mucosa, and regenerative and neoplastic changes at variable imaging depths in high resolution comparable to those with intravenous fluorescein. By cytoplasmic enrichment of CV, nuclear morphology could be negatively visualized. Reliable differentiation of nonneoplastic versus neoplastic changes during ongoing endoscopy and a high interobserver agreement based on the microscopic images generated in vivo could be achieved.nnnLIMITATIONSnSingle-center study, nonrandomized, limited number of patients.nnnCONCLUSIONSnCV can be applied topically and allows simultaneous chromoendoscopy and endomicroscopy with accurate prediction of histology with visualization of nuclear morphology. It may therefore be a single-agent alternative to chromoendoscopy and fluorescein in endomicroscopy.

Mini-laparoscopy in the endoscopy unit.

Purpose of review The evaluation of liver histology is an important component of the diagnosis and staging of liver diseases. The most common technique employed to sample liver tissue for decades has been percutaneous liver biopsy. Although this is a relatively well tolerated technique in the early stages of liver disease, it carries a high risk of complications, particularly hemorrhage, in patients with advanced cirrhosis. Mini-laparoscopy allows macroscopic assessment and biopsy under direct vision and therefore is a well tolerated and effective technique. Recent findings The major advantages of this technique are direct visualization of the liver surface, thereby allowing inspection for morphologic changes of cirrhosis as well as targeted biopsies, the ability to immediately treat potential complications (bleeding and bile leakage), furthermore the peritoneal cavity can be visualized to stage gastrointestinal (GI) malignancies. Additionally, ‘blind’ percutaneous liver biopsy fails to establish a diagnosis in about 25% of cases, largely because of sampling error. Summary This technique presents the opportunity to visualize the surface of the liver and the peritoneal cavity, making it a valuable tool for liver biopsy. This review summarizes the technique of mini-laparoscopy and addresses its potential uses and limitations as a diagnostic modality.