Focal residual contrast media in the kidney 24 hours after angiography

Persistent CT nephrograms following cardiac catheterisation and intervention: initial observations

Objectives

To describe persistent nephrographic patterns detected by unenhanced renal CT at 24 h after cardiac catheterisation and intervention.

Methods

This prospective study was Health Insurance Portability and Accountability Act-compliant and institutional review board approved. Twenty-nine patients (20 men, nine women; average age 63.27 and range 41–85 years) agreed to undergo unenhanced dual-energy computed tomography (CT) limited to their kidneys at 24 h after cardiac catheterisation. CT attenuation values (Hounsfield units) were made from the cortical and medullary regions and single kidney total parenchymal iodine values (milligrams) were measured. Spearman’s rank correlation coefficient and a two-sided Fisher’s exact test were used in the statistics.

Results

Focal nephrograms were observed in at least one kidney (range, one to five regions per kidney) in 10/29 (34%) of patients and bilateral global nephrograms in 13/29 (45%) of patients. Focal nephrograms correlated with cardiac catheterisation fluoroscopic time (r = 0.48; P = 0.0087). For global nephrograms, the total iodine content of right and left kidneys correlated with fluoroscopic time (r = 0.79 and 0.76; P < 0.0001, respectively) and the amount of contrast material (CM) used (r = 0.77 and r = 0.74; P < 0.0001, respectively).

Conclusion

Persistent focal and global nephrograms occur commonly as assessed by non-contrast CT at 24 h post cardiac catheterisation and our observations suggest they could be related to procedural factors.

Electronic supplementary material

The online version of this article (doi:10.1007/s13244-011-0131-2) contains supplementary material, which is available to authorized users.

Retention of iodine and expression of biomarkers for renal damage in the kidney after application of iodinated contrast media in rats

OBJECTIVE

Commercially available iodinated contrast media (CM) show significantly different physico-chemical properties. The relevance of the viscosity of CM may be underestimated as a contributing factor for clinically relevant renal failure as suggested by a large registry data analysis (Swedish registry study). The objective of this preclinical study is to assess differences of a low and high-viscous CM regarding their retention time in the kidney. Furthermore, we investigated the expression of marker genes for renal damage and hypoxia to evaluate a potential renal damage and hypoxia after application of iodinated CM.

MATERIAL AND METHODS

After application of Iopromide 300 and Iodixanol 320 CM, the iodine concentration over time was determined using computed tomography and x-ray fluorescence analysis in healthy Han Wistar and renally impaired ZSF1 rats. The latter served as a model for age and diabetes-related renal impairment. X-ray attenuation (Hounsfield units) in the renal cortex was analyzed by 2 independent blinded readers. Furthermore, the expression of kidney injury molecule 1 (Kim-1/Havcr1) and heme oxygenase I (HO-1/HMOX1) was measured by quantitative reverse transcription-polymerase chain-reaction.

RESULTS

Computed tomography and x-ray fluorescence analysis in the kidneys of animals treated with Iodixanol revealed significantly prolonged retention of iodine in the kidney as compared with animals treated with Iopromide. This difference was even more pronounced in renally impaired rats. Twenty-four hours after Iodixanol treatment, significantly increased levels of Kim-1/Havcr1 and HO-1/HMOX1 transcript levels were observed compared with the saline and Iopromide treatment.

CONCLUSIONS

A prolonged retention of contrast media in the kidney was observed after administration of dimeric CM (Iodixanol 320). One possible explanation for this effect could be the high viscosity of the dimeric CM (Iodixanol 320) and the lack of dilution by osmotic diuresis. This prolonged exposure is possibly associated with higher renal toxicity as indicated by the elevated expression of biomarkers for hypoxia and renal injury.