Radiation exposure during nasojejunal intubation for MRI enteroclysis

Abstract

Background. Patients with Crohn's disease are often investigated using MRI enteroclysis which may provide better visual quality than MRI enterography, but exposes patients to radiation. Only few data exist of the radiation dose used in fluoroscopy prior to MRI enteroclysis. Subjects and methods. During the 12-month study period, all 95 patients (40 men) undergoing MRI enteroclysis with nasojejunal intubation using fluoroscopy for suspicion or evaluation of Crohn's disease were included. Average age at the time of MRI was 40.1 years (range 17–79). Conversion factors from dose-area product to effective dose were determined with a Monte Carlo-based software PCXMC. The conversion factors were determined for a standard-sized adult phantom for posterior–anterior and right-posterior–oblique projections. Results. The average total time of fluoroscopy was 3 min 17 s (range 0 min 7 s to 31 min). The average effective dose of ionizing radiation was 0.21 mSv (range 0.01–2.67). The average dose is equivalent to 10 PA chest x-rays. Standard deviation was 0.41 mSv. The highest effective dose of a single patient was 2.67 mSv. In comparison, a standard abdominal CT scan causes an effective dose of 12 mSv. Conclusions. The effective dose of ionizing radiation with nasojejunal intubation is relatively small in the majority of patients. When repeated imaging is necessary, it seems advisable to consider imaging techniques, which do not subject patients to ionizing radiation. Also if a previous nasojejunal intubation has been difficult, a different imaging technique is recommended.

Key Words::

• Crohn's disease
• small bowel examination
• small bowel imaging
• small intestine

Acknowledgements

We thank Mrs. Maritta Suominen for excellent assistance. This work was financially supported by The Mary and Georg C. Ehrnrooth Foundation.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.