A randomized, comparative, animal survival study of colonic tattoing using indocyanine green or India ink

A. H. Low, J. G. Lee, Joseph Leung

Research output: Contribution to journalArticlepeer-review


Purpose: To compare the efficacy, durability, and safety of Indocyanine green to India ink for endoscopic colonic tattooing. Methods: Four pigs (30-35 kg) were randomized to undergo colonic tattooing using India ink or Indocyanine green (Cardiogreen, Bectin Dickinson & Co., Chicago, IL). The animals were fasted, but given free access to water for 24 hours and prepared using tap water enemas on the morning of the procedure. After the animals were sedated, paralyzed and intubated, sigmoidoscopy was performed to 60 cm (GIF2T100, Olympus Co., Tokyo, Japan). Submucosal injections of 0.5 ml aliquots of India ink or Indocyanine green were performed every 2-5 cm to raise a bleb. Commercial, artist grade India ink was diluted 1:10 using normal saline and filtered through 2 tandem Millipore filters (0.22μ and 0.45μ) and the Indocyanine green was reconstituted according to the manufacturer's instructions. The animals were recovered and maintained for 2 weeks and humanely sacrificed. All visible tattoo sites were examined grossly and histologically during post mortem examination with particular attention to stain intensity, hemorrhage, perforation, inflammation, abscess and staining of associated lymph nodes. The durability of the tattooing agent was graded as: 1-no change in intensity, 2-slight decrease in intensity, 3-faint staining. Results: A total of 11 sites were tattooed in 2 pigs using Indocyanine green and 28 sites using India ink in 2 pigs. The total number of tattoos were determined by the quality of the colonic lavage which was highly variable. All animals survived without obvious clinical complications. Indocyanine green was easier and faster to prepare and inject compared to the India ink. Post mortem examination easily identified 9 of 11 Indocyanine green tattoos (82%) and 26 of 28 India ink tattoos (93%) on the colonic serosa, (p>0.05). The diameter of the tattoos ranged between 5-15mm for the Indocyanine green and 10-15mm for the India ink group (p>0.05), and the mean scores for the durability of the tattoo were 2.5 and 3, (p>0.05). Histopathologic examination failed to show perforation, hemorrhage, abscess, or granuloma, but a mild inflammatory response was seen in 6 of 11 (67%) Indocyanine green tattoos and 14 or 28 (50%) India ink tattoos (p>0.05). The pharmacy costs of Indocyanine green ($17/ animal) was higher compared to the India ink plus the filters ($5/animal). Conclusions: Indocyanine green is as effective, durable, and safe as India ink when used for colonic tattooing. Although Indocyanine green is significantly easier and faster to use compared to the commercially available India ink, which must be sterilized before injection, it is more costly. Endoscopic equipment was provided by Olympus Co., Tokyo, Japan.

Original languageEnglish (US)
JournalGastrointestinal Endoscopy
Issue number4
StatePublished - 1998

ASJC Scopus subject areas

  • Gastroenterology


Dive into the research topics of 'A randomized, comparative, animal survival study of colonic tattoing using indocyanine green or India ink'. Together they form a unique fingerprint.

Cite this