Effect of Iodized contrast substances used in computed tomography examination on kidney apparent diffusion coefficient (ADC) value

Aim: In this prospective study, our goal is to evaluate the effect of iodine-based contrast agent on renal Apparent Diffusion Coefficient (ADC) before and after the contrast agent in patients with normal and abnormal Glomerulary Filtration Rate (GFR) values using computed tomography (CT) imaging.Methods: The patients who applied for CT examination at an age older than 40 years and met the inclusion criteria of patient and control groups were included. DWI was evaluated by two radiologist in the same session. The range of interest (ROI) was adjusted to be less than 1.5 cm².The Spearman correlation test was used for statistical analysis.Results: A total of 48 subjects (23 and 25 subjects for patient and control groups, respectively) with two DWI scans were included. ADC values were compared for both kidneys before and after the administration of the contrast agent and a significant decrease in post-ADC values was observed in the control group (right kidney pre-ADC: 2,11±0,17 x10ˉ³, post-ADC 2,07±0,15 x10ˉ³ mm²/s, p=0,016; left kidney pre-ADC: 2,11±0,17 x10ˉ³ mm²/s, post-ADC 2,04±0,14 x10ˉ³ mm²/s, p=0,011). However, there was no significant difference between the patient groups according to the administration of contrast agent (right kidney pre-ADC: 1,97±0,22 x10ˉ³ mm²/s, post-ADC: 1,97±0,24 x10ˉ³ mm²/s, p=0,95; left kidney pre-ADC: 1,96±0,23 x10ˉ³ mm²/s, post-ADC: 1,98±0,22 x10ˉ³ mm²/s, p=0,64). Moreover, pre-ADC values in the patient group were relatively low. Pre-ADC values in both groups for the right kidney were 1,97±0,22 x10ˉ³ mm²/s and 2,11±0,17 x10ˉ³ mm²/s, respectively (p=0,016). Pre ADC values in both groups for the left kidney were 1,96±0,23 x10ˉ³ mm²/s and 2,11±0,17 x10ˉ³ mm²/s, respectively (p=0,018). No significant differences in the post-ADC values were observed between the two groups.Conclusion: No decrease in ADC values was observed after the administration of iodine-based contrast agent in patients with a GFR less than 60, whereas there was a relatively high decrease in patients with normal GFR.