BACKGROUND: Iodine in iodinated contrast agents (ICAs) interferes with radioactive iodine treatment (RAIT) and diagnostic scans in patients with differentiated thyroid carcinoma (DTC) because it can compete with ¹³¹I. Published guidelines recommend delaying RAIT for three to four months in patients who have been exposed to ICA. Spot urinary iodine concentration is a useful marker to reflect the body iodine pool. We investigated the impact of ICAs administered at preoperative computed tomography (CT) scan on the body iodine pool to determine the proper time interval between preoperative CT and RAIT in DTC patients. METHODS: We performed a retrospective review of 1023 patients with DTC who underwent a preoperative CT scan with ICA, total thyroidectomy, and one week of low-iodine diet in preparation for RAIT. Urine iodine excretion (UIE) was measured in spot urine by inductively coupled plasma mass spectrometry and reported both in simple concentration (μg/L) and divided by gram creatinine (μg/gCr). Patients were divided into five groups by time interval in days between preoperative CT scan and spot urine iodine measurement (A, 31-60 [n=29]; B, 61-90 [n=155]; C, 91-120 [n=546]; D, 121-150 [n=226]; E, 151-180 [n=67]). RESULTS: The median (interquartile range) of UIE (μg/gCr) in each group was 44.4 (27.7-73.2) in group A, 33.3 (22.8-64.7) in group B, 32.7 (20.8-63.0) in group C, 32.0 (20.6-67.0) in group D, and 30.4 (19.6-70.8) in group E. There was no significant difference between group A and the remaining groups (p>0.05) Also, the proportion of patients who achieved the appropriate UIE for RAIT according to our hospital's cutoff (≤66.2 μg/gCr) was not different between groups (A, 72.4%; B, 76.1%; C, 77.5%; D, 74.8%; E, 74.6%) (p=0.78). CONCLUSION: This study shows that a UIE of one month after preoperative CT scan with ICA was not higher than that of six months after CT scan in patients who underwent total thyroidectomy for DTC. Thus, current guidelines that recommend delay of RAIT for three to four months after CT scan with ICA should be revisited and future studies to clarify the appropriate time interval between CT scan with ICA and RAIT are warranted.
BACKGROUND:Iodine in iodinated contrast agents (ICAs) interferes with radioactive iodine treatment (RAIT) and diagnostic scans in patients with differentiated thyroid carcinoma (DTC) because it can compete with ¹³¹I. Published guidelines recommend delaying RAIT for three to four months in patients who have been exposed to ICA. Spot urinary iodine concentration is a useful marker to reflect the body iodine pool. We investigated the impact of ICAs administered at preoperative computed tomography (CT) scan on the body iodine pool to determine the proper time interval between preoperative CT and RAIT in DTCpatients. METHODS: We performed a retrospective review of 1023 patients with DTC who underwent a preoperative CT scan with ICA, total thyroidectomy, and one week of low-iodine diet in preparation for RAIT. Urine iodine excretion (UIE) was measured in spot urine by inductively coupled plasma mass spectrometry and reported both in simple concentration (μg/L) and divided by gram creatinine (μg/gCr). Patients were divided into five groups by time interval in days between preoperative CT scan and spot urine iodine measurement (A, 31-60 [n=29]; B, 61-90 [n=155]; C, 91-120 [n=546]; D, 121-150 [n=226]; E, 151-180 [n=67]). RESULTS: The median (interquartile range) of UIE (μg/gCr) in each group was 44.4 (27.7-73.2) in group A, 33.3 (22.8-64.7) in group B, 32.7 (20.8-63.0) in group C, 32.0 (20.6-67.0) in group D, and 30.4 (19.6-70.8) in group E. There was no significant difference between group A and the remaining groups (p>0.05) Also, the proportion of patients who achieved the appropriate UIE for RAIT according to our hospital's cutoff (≤66.2 μg/gCr) was not different between groups (A, 72.4%; B, 76.1%; C, 77.5%; D, 74.8%; E, 74.6%) (p=0.78). CONCLUSION: This study shows that a UIE of one month after preoperative CT scan with ICA was not higher than that of six months after CT scan in patients who underwent total thyroidectomy for DTC. Thus, current guidelines that recommend delay of RAIT for three to four months after CT scan with ICA should be revisited and future studies to clarify the appropriate time interval between CT scan with ICA and RAIT are warranted.
Authors: Se Jin Cho; Chong Hyun Suh; Jung Hwan Baek; Sae Rom Chung; Young Jun Choi; Jeong Hyun Lee Journal: Eur Radiol Date: 2019-02-26 Impact factor: 5.315
Authors: Sun Y Lee; Donny L F Chang; Xuemei He; Elizabeth N Pearce; Lewis E Braverman; Angela M Leung Journal: Thyroid Date: 2015-03-23 Impact factor: 6.568
Authors: Eun Ju Ha; Sae Rom Chung; Dong Gyu Na; Hye Shin Ahn; Jin Chung; Ji Ye Lee; Jeong Seon Park; Roh-Eul Yoo; Jung Hwan Baek; Sun Mi Baek; Seong Whi Cho; Yoon Jung Choi; Soo Yeon Hahn; So Lyung Jung; Ji-Hoon Kim; Seul Kee Kim; Soo Jin Kim; Chang Yoon Lee; Ho Kyu Lee; Jeong Hyun Lee; Young Hen Lee; Hyun Kyung Lim; Jung Hee Shin; Jung Suk Sim; Jin Young Sung; Jung Hyun Yoon; Miyoung Choi Journal: Korean J Radiol Date: 2021-10-26 Impact factor: 3.500
Authors: Bernadette L Dekker; Daan J Touw; Anouk N A van der Horst-Schrivers; Michel J Vos; Thera P Links; D A Janneke Dijck-Brouwer; Anneke C Muller Kobold Journal: J Nutr Date: 2021-12-03 Impact factor: 4.798