Gastrografin can be detected in ex vivo biological specimens by dual‐energy CT scanning

Abstract

Background: Dual-energy CT is able to distinguish between materials based on differences in X-ray absorption at different X-ray beam energies. The strong k-edge photoelectric effect of materials with a high atomic number makes this modality ideal for identifying iodine-containing compounds. We aim to evaluate dual-energy CT for the detection of Gastrografin (GG) (diatrizoate, Bayer PLC, Reading, UK) enteric contrast medium and validate the conditions for the measurement in ex vivo samples. Methods: Dual-energy CT acquisitions were performed to detect Gastrografin in serial dilutions of water, saline and body fluids. We also evaluated the stability of Gastrografin solutions over time at room temperature. Stool specimens were examined to validate the proposed study protocol for clinical applications. Results: Concentrations as low as 0.2% of Gastrografin were reproducibly detected in vitro and ex vivo samples by DECT, with linear readings ranging from 0.2% to 25% Gastrografin. Gastrografin was shown to be stable in ex vivo biological samples, and there was no difference in detection over time. Gastrografin was detected in stool specimens when administered orally. The detection curves followed the expected saturation effect at high concentrations of iodine. Conclusions: Dual-energy CT offers a convenient, quick, reliable and reproducible method for detecting and quantifying the presence of Gastrografin in ex vivo clinical specimens. Biological solutions containing Gastrografin are stable over time. A minimum dilution level of 25% is suggested to avoid beam saturation and inaccurate results.

A development study of drain fluid gastrografin as a biomarker of anastomotic leak

“…The upper limit of the true negative levels of GG measured in drain fluid by DECT was derived by calculating the mean (+3 standard deviation (SD)) iodine density (mg/mL) in GG negative samples. We have established measurements of iodine density above 1.2 mg/mL to represent a positive result for the presence of GG in a solution measured by DECT [ 4 ].…”

“…We have established measurements of iodine density above 1.2 mg/ml to represent a positive result for the presence of GG in a solution measured by DECT. [4]…”

“…The iodine in GG can be measured directly and quantitated with dual-energy CT (DECT) and the protocol has been established and validated in a prior study (imaging protocol in Appendix 1 ) [ 4 ]. In patients who routinely have a rectal tube inserted, after a low colorectal anastomosis, this tube may be flushed with GG quarter in die (QID).…”

Does an ileostomy cover the surgeon or the anastomosis?

“…The measurement of drain fluid amylase or drain fluid Gastrografin may achieve this end and there is emerging evidence of their utility as sensitive BMs for early AL. [17][18][19][20][21] Patients without a TDI are likely to present more dramatically and earlier in their post-operative recovery.…”

An umbrella systematic review of drain fluid analysis in colorectal surgery for the detection of anastomotic leak: Not yet ready to translate research studies into clinical practice

“…Two assessed drain fluid gastrografin as a BM, in phase 1 and 2 studies. The authors defined a threshold level of 0.2% gastrografin (1.23 mg/ml iodine) as measured by dual energy computerised tomography [34] and two assessed drain fluid amylase and lipase in ileal patients and those undergoing a low anterior resection. A pilot study of 13 ileal pouch patients suggested that drain fluid amylase might be a sensitive BM of AL [35].…”