Special Clinical Interests

One of Dr. Rex’s principle clinical research interests is the technical performance of colonoscopy. His work has focused on colonoscopy technique and imaging technologies that maximize the detection of cancers and precancerous polyps during colonoscopy. At Indiana University Hospital, emphasis is placed on slow and meticulous examination technique that maximizes the detection of even the smallest precancerous polyps. In conjunction with Olympus Corporation, Dr. Rex first demonstrated the extremely high yield of precancerous polyp detection with the use of high-definition colonoscopes. These colonoscopes are currently in use in Dr. Rex’s practice at Indiana University Hospital and at the Spring Mill Surgery Center at 103^rd and Meridian Street in Indianapolis. These colonoscopes also provide narrow-band imaging, in which polyps can be examined in blue light as well as white light. Blue light allows prediction of precancerous verus non-precancerous polyps.
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During colonoscopy, all potentially precancerous polyps should be fully resected. Large polyps with a broad-based attachment to the colon wall are often considered the technically most difficult polyps to resect during colonoscopy. Many of these larger broad-based (sessile) colon polyps are sent for surgical resection across the United States; however, many patients would prefer to have their polyps removed by colonoscopy and in many cases this is possible. Dr. Rex has reported extensive experience with advanced polypectomy techniques, including submucosal injection, piecemeal polypectomy, and ablation with argon plasma coagulation. The risks of resecting these large polyps are higher than the resection of small polyps but still overall are quite low, with a risk of significant bleeding after resection of about 5% and a risk of perforation requiring surgery of about 0.5%. Endoscopic photographs of polyps can be submitted to Dr. Rex for consideration of the feasibility of resection by colonoscopy (contact Kelly at 317-278-9763 to send photos or arrange e-mailing). Resection by colonoscopy typically requires at least one followup examination at Indiana University Hospital to confirm complete resection.


Large rectal polyp		After injection and resection of the first piece

After removal of additional large sections		After removal of the last large piece

After trimming of the edges and treatment with APC

Another special interest for Dr. Rex is the completion of colonoscopy in patients who have had previous attempts at colonoscopy that were unsuccessful. These attempts may be necessary because of clinical indications such as persistent iron deficiency anemia, visualization of a polyp by the previous colonoscopy which was in the distant endoscopic field but which could not be reached by the prior colonoscopy, or detection of polyps on a barium enema or virtual colonoscopy done to complete a prior examination. Dr. Rex has published the world’s only experience in such cases and has achieved a success rate of 98% in completing examinations, by using attention to colonoscopy technique and specialized colonoscopy equipment.

Rex DK, Goodwine BW. Method of colonoscopy in 42 consecutive patients presenting after prior incomplete colonoscopy. Am J Gastroenterol 2002;97:1148-51.

Rex DK, Chen SC, Overhiser AJ. Colonoscopy technique in consecutive patients referred for prior incomplete colonoscopy. Clin Gastroenterol Hepatol 2007;5:879-83.

Barrett’s esophagus is a precancerous condition in which the lining of the esophagus changes from normal squamous lining to a type of lining found in the intestine. This new lining is at risk for developing cancer. Some patients develop dysplasia. New techniques allow areas of Barrett's to be resected through the endoscope (endoscopic mucosal resection) or ablated by burning the esophagus (BARRX treatment). Dr. Rex has extensive expertise in both of these techniques as well as photodynamic therapy.