Effects of Iodinated Contrast-enhanced CT on Urinary Iodine Levels in Postoperative Patients with Differentiated Thyroid Cancer.

AIMS: This study aims to observe the fluctuating urine iodine levels in patients with differentiated thyroid cancer (DTC) following iodinated contrastenhanced computed tomography (eCT) scans. BACKGROUND: The presence of iodine in iodinated contrast agents (ICAs) can impede the effectiveness of radioactive iodine treatment (RAIT) and diagnostic scans in individuals diagnosed with DTC, as it can engage in competitive interactions with 131I. According to established guidelines, it is recommended to postpone RAIT for a period of three to four months in individuals who have had prior exposure to ICAS. The measurement of spot urine iodine concentration is a valuable indicator for assessing the overall iodine content throughout the body. OBJECTIVE: The objective is to identify the optimal timing for administering postoperative RAIT in DTC patients. METHODS: At various time points after surgery, a cohort of 467 random urine samples (126 male samples, 341 female samples, age (45±12 years)) was obtained from 269 DTC patients. The samples were analyzed for urinary iodine and urinary creatinine levels, and the urinary iodine/urine creatinine ratio (I/Cr) was computed. All samples were divided into two groups according to whether eCT before operation: the non-enhanced CT (eCT-) group and the enhanced CT (eCT+) group. The urine samples in the eCT- group were categorized into four subgroups according to the duration of strict low iodine diet (LID): (eCT-I+) no LID; (eCT-I-2W) 2 weeks of LID; (eCT-I-4W) 4 weeks of LID; and (eCT-I-6W) 6 weeks of LID. The last three groups were merged into the eCT- and effective LID group (eCT- I-). The urine samples from the eCT+ group were categorized into five subgroups: (0.5M eCT+)0.5 month after eCT+; (1M eCT+)1 month after eCT+; (2M eCT+) 2 months after eCT+; (3M eCT+) 3 months after eCT+; (≥4M eCT+) ≥4 months after eCT+. In addition, the patients within 2 months after eCT+ were divided into 2 groups according to their LID: no effective LID group (eCT+ I+) and effective LID group (eCT+ I-). Utilizing the Kruskal-Wallis and Mann-Whitney U rank sum tests, the differences in I/Cr between groups were compared. RESULTS: In the eCT-group, the I/Cr ratios of eCT-I-2W, eCT-I-4W, and eCT-I-6W were significantly lower than those of eCT-I+ (χ2 values: 4.607.99, all P 0.05). However, there was no significant difference in I/Cr between eCT-I-2W, eCT- I-4W, and eCT-I-6W (2 values: 0.591.31, all P > 0.05). Significantly higher I/Cr values were observed in 0.5M eCT+ and 1M eCT+ than in eCT-I+ (χ2 values: 3.22 and 2.18, respectively, all P<0.05). There was no significant difference in I/Cr between 2M eCT+ and eCT-I+ (χ2 = 0.76, P = 0.447). The I/Cr rations of 3M eCT+, ≥4M eCT+ were not significantly different with eCT-I- (χ2 values: 1.76; 0.58; all P > 0.05). However, they were considerably lower than eCT-I+ (χ2 values: 7.03; 5.22; all P<0.05). The I/Cr for patients who underwent eCT within two months (eCT+ I-, eCT+ I+) did not differ significantly (χ2 = 1.79, P = 0.073). CONCLUSION: For patients who are considering receiving radioactive iodine therapy (RAIT) following a diagnosis of differentiated thyroid cancer (DTC), it is recommended that the interval between RAIT treatment and enhanced computed tomography [eCT] scans be conducted at least three months.

Study on relationship between urine iodine level in different pregnant periods of women and thyroid function / 国际检验医学杂志

Objective To analyze the relationship between the urine iodine level in different pregnant periods of women and the thyroid function .Methods The pregnant women were randomly sampled in Foshan city and 490 cases were selected as the research subjects ,including 170 cases of early stage pregnancy ,162 cases of middle stage pregnancy and 158 cases of late stage pregnancy . According to the thyroid function ,490 subjects were divided into the normal thyroid function group and the abnormal thyroid func‐tion group .Results 140 cases(88 .61% ) in the late stage pregnancy had normal thyroid function ,which were less than 166 cases (97 .65% ) in the early stage pregnancy and 157 cases (96 .91% ) in the middle stage pregnancy ;the constituent ratio of urine iodine < 100 μg/L in the early stage pregnancy was 19 .88% (33/166) in the normal thyroid function ,which was lower than 75 .00%(3/5) in the abnormal thyroid function group .The constituent ratio of urine iodine 100 - 300 μg/L in the early stage pregnancy group was 56 .0% (93/166) ,which was higher than 0 .0% (0/4) in the of abnormal thyroid function group .Conclusion It is neces‐sary to conduct the urinary iodine monitoring in early pregnant woman ,moreover it is suggested that the thyroid function detection will be conducted in the pregnant women with urine iodine < 100 μg/L and urine iodine 100 - 300 μg/L .

Analysis on the frequency of urinary iodine in a population-based intervention study / 中华流行病学杂志

Objective Through a two-year follow up program,this study was to analyze the urinary iodine frequency of a cohort in the intervention trial,concerning different doses of salt iodization,so as to explore the selection of appropriate concentration of salt iodization.Methods A multistage cluster sampling method was used to select three townships in two countries for community intervention with different doses [ ( 15 ± 5 ) mg/kg,(25 ± 5 ) mg/kg,( 35 ± 5 ) mg/kg ] of salt iodization.Results After intervention,the median of urinary iodine was reduced among the population.The urinary iodine frequencies of (15 ± 5) mg/kg and (25 ± 5) mg/kg among groups of children were mainly concentrated in 100-200 μg/L and 200-300 μg/L paragraphs in A county.While the 300 μg/Lparagraph had an overall decline in B county,the 100 μtg/L and 200 μg/L paragraph ratio increased but the trend seemed to be slow.The 100-300 μg/L paragraph of the four treatment groups took a larger proportion and kept smooth in a more ideal state.However,the control group still maintained at above 250 μg/L level.Conclusion The iodine supplementation should be gradually implemented in Chongqing.The doses of salt iodization should be reduced from the current (35 ± 15)mg/kg to (25 ± 5) mg/kg in the economically developed areas.At the same time,we need to continuously follow the changes of the condition.

Study on the feasibility of urine iodine level of children in different age at different times instead morning urine / 重庆医科大学学报

Objective:To study the feasibility of urinary iodine level at different times instead morningurine. Methods:We selected the urinaryiodine ofchildren aged 8~10 with stratified random sample method,collected the urine samples in the morning and at 10:00、12:30、4 pm and compared the difference of the urinary iodine level at different time. Results:There were significant differences between urinary iodine level in different time,different time interact with different age on the urinary iodine level,but do not with different sex by ANOVA with repeated measurement.There were no significant differences between morning Urinary iodine and at loan. Conclusion:There was the differences of urinary iodine between different ages,different time.It was feasible that use urinary iodine level by ANOVA with repeated measurement.T hter were NO significant differences between morning urinary iodine and at 10am.at 10am to replace the level of morning.