Urinary iodine excretion after contrast computed tomography scan: implications for radioactive iodine use

Grace L Nimmons; Gerry F Funk; Michael M Graham; Nitin A Pagedar

doi:10.1001/jamaoto.2013.2552

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Urinary iodine excretion after contrast computed tomography scan: implications for radioactive iodine use

Journal article

Open access

Peer reviewed

Urinary iodine excretion after contrast computed tomography scan: implications for radioactive iodine use

Grace L Nimmons, Gerry F Funk, Michael M Graham and Nitin A Pagedar

JAMA otolaryngology-- head & neck surgery, Vol.139(5), pp.479-4

05/2013

DOI: 10.1001/jamaoto.2013.2552

PMID: 23599025

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Abstract

Patients who undergo radiographic studies with contrast receive an enormous bolus of iodine. This can delay subsequent use of radioactive iodine (RAI) therapy because the iodine can compete for uptake. There is a paucity of literature on the minimum interval between contrast administration and RAI therapy. To better characterize how long it takes for the iodine load from an intravenous contrast bolus to clear from the body. A prospective cohort of 21 adults undergoing intravenous contrast CT studies at a tertiary academic medical center; exclusion criteria included history of thyroid disease or thyroidectomy, history of renal insufficiency, pregnancy, and other contrast administration within 1 year. Morning urine samples were taken before the scan for analysis and then every 2 weeks thereafter for 12 weeks. RESULTS The median baseline iodine level was 135 μg/L (range, 29-1680 μg/L), and median peak level was 552 μg/L (range, 62-6172 μg/L). Median time for urinary iodine level to normalize was 43 days, with 75% of subjects returning to baseline within 60 days, and 90% of subjects within 75 days. Baseline iodine level was a significant predictor of postcontrast iodine levels. Age, sex, weight, and estimated glomerular filtration rate were not significant. These results may be used for guidance on the timing of RAI use following contrast exposure. The practice at our institution is to wait 2 months and then check a 24-hour urinary iodine level. This alleviates concerns about contrast use in patients with thyroid carcinoma interfering with adjuvant radioiodine therapy.

Prospective Studies

Tertiary Care Centers

Age Factors

Risk Assessment

Humans

Middle Aged

Kaplan-Meier Estimate

Tomography, X-Ray Computed - methods

Male

Pregnancy

Young Adult

Tomography, X-Ray Computed - adverse effects

Contrast Media - adverse effects

Iodine Radioisotopes - urine

Time Factors

Sex Factors

Monitoring, Physiologic - methods

Adult

Female

Aged

Infusions, Intravenous

Cohort Studies

Iodine - urine

Details

Title: Subtitle: Urinary iodine excretion after contrast computed tomography scan: implications for radioactive iodine use
Creators: Grace L Nimmons - Department of Otolaryngology–Head and Neck Surgery, University of Iowa, Iowa City, IA, USA
Gerry F Funk
Michael M Graham
Nitin A Pagedar
Resource Type: Journal article
Publication Details: JAMA otolaryngology-- head & neck surgery, Vol.139(5), pp.479-4
DOI: 10.1001/jamaoto.2013.2552
PMID: 23599025
NLM abbreviation: JAMA Otolaryngol Head Neck Surg
ISSN: 2168-6181
eISSN: 2168-619X
Publisher: United States
Language: English
Date published: 05/2013
Academic Unit: Radiology; Radiation Oncology; Otolaryngology
Record Identifier: 9984006321202771

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41 Times Cited - Web of Science