The influence of iodinated contrast agent to the value of kidney apparent diffusion coefficient (ADC)

aim: In this study, we aim to evaluate the efect of iodinated contrast agents to kidney ADC values, before and after the administration, on patients underwent Computed Tomography (CT) examination. Material-Methodology: Among the patients who applied to our department for CT examination, those were above 40 years old and found suitable for the exclusion and inclusion criterias to patient and control group, were taken into study. Diffusion weighted imaging (DWI)(b=0,b=800) was done before and 48-72 hours after the CT targeted at the kidneys. The value of urea-creatinin was measured twice before CT and on the day of DWI. DWI were evaluated by two experienced radiologists, one having four years and the latter having ten years of experience, at the same session. Apparent Diffusion coefficient (ADC) measures were taken from both kidneys before and after the contrast; and from upper, middle and lower part. Range of interest (ROI) was adjusted to be less than 1.5 cm². Findings: 23 patients and 25 control group. with two DWI were included in our study. ADC values before and after the contrast agent administration for both kidneys were compared and a significant decrease were detected in ADC values in the control group after administration (right kidney ADC before the administration: 2,11±0,17 x10ˉ³, after 2,07±0,15 x10ˉ³ mm²/sn, p=0,016; left kidney ADC before the administration: 2,11±0,17 x10ˉ³ mm²/sn, after 2,04±0,14 x10ˉ³ mm²/sn, p=0,011). In the patient group, no significant difference before and after the contrast was found. (right kidney ADC before the contrast:: 1,97±0,22 x10ˉ³ mm²/sn, after 1,97±0,24 x10ˉ³ mm²/sn, p=0,95; left kidney ADC before the contrast 1,96±0,23 x10ˉ³ mm²/sn, after 1,98±0,22 x10ˉ³ mm²/sn, p=0,64 were measured.) Furthermore, ADC values in the patient group before the administration was found to be significantly low. (Values in patient and control group for the right kidney before the administration, respectively: 1,97±0,22 x10ˉ³ mm²/sn, 2,11±0,17 x10ˉ³ mm²/sn p=0,016, for the left v kidney before the administration 1,96±0,23 x10ˉ³ mm²/sn, 2,11±0,17 x10ˉ³ mm²/sn, p=0,018). No significant difference after the contrast was observed. Conclusion: There was no decrease in ADC values after the use of Iodised non-ionic substance in patients with a GFR is less than 60, whereas a significant decrease was observed with those who had normal GFR. Key words: GFR, DAG-MRG, ADC, contrast agents, CT