Effects of two low osmolality contrast media on red blood cell filterability and aggregation in vitro.

The in vitro effects of ionic ioxaglate and non-ionic iopamidol were compared. Filtration measurements were carried out on an hemorheometer; erythrocyte aggregation was evaluated by means of an erythrocyte aggregometer, and red blood cell morphology was observed with an optical microscope. Ioxaglate and iopamidol reduced erythrocyte filterability to the same extent; by contrast neither ionic nor non-ionic contrast media significantly modified aggregation or shape of red blood cells. The decrease of erythrocyte deformability observed in this study may cause clotting in catheters or syringes during angiographies investigations.     

The effect of radiographic contrast media on ultrasonically detectable red blood cell aggregation in vitro

We investigated the effect of radiographic contrast media (RCM) on red blood cell (RBC) aggregation by analyzing echogenicity of flowing blood before and after the addition of 2%, 20%, 50% or 95% volume of undiluted meglumine diatrizoate, iohexol, sodium meglumine ioxaglate, or iopamidol and equiosmolar volume concentration of saline. This was done both by stepwise increasing the concentration with minimal mixing and by stepwise decreasing the concentrations with more efficient mixing. All contrast media caused a drop in blood echogenicity after a proper mixing when compared with saline addition. After minimal stirring, both meglumine diatrozoate and iohexol caused a significant increase in blood echogenicity at volume concentrations over 50%. The paper demonstrates that earlier findings of both increased and decreased RBC aggregation following exposure to RCM can be reproduced and that the result depends on experimental setup. In diatrizoate and iohexol RBC aggregates disappear after mixing (increasing the shear rate) or when the RCM/blood mixture is diluted. After dispersement, the abnormal RBC aggregates will not reform.     

Thrombosis following phlebography with ionic and non-ionic contrast media.

The side-effects at phlebography of the lower limb were evaluated using an ionic contrast medium, meglumine-metrizoate, and a non-ionic contrast medium, metrizamide. A post-phlebographic accumulation of 125I-fibrinogen was found in 6 patients examined with meglumine-metrizoate indicating a post-phlebographic thrombosis. Ten patients were examined with metrizamide with no post-phlebographic increase in 125I-fibrinogen uptake. Though the groups are small the difference is statistically significant at the 0.2 per cent level.     

Water-soluble contrast media in radiography of small bowel obstruction. Comparison of ionic and non-ionic contrast media

Fifty patients with possible gastrointestinal obstruction, referred for enteric follow-through examination, were randomized for a double-blind, parallel comparison of the hyperosmolar contrast medium Gastrografin and the low-osmolar Omnipaque. The result was that Omnipaque retained its radiographic density in the small bowel better than Gastrografin. Omnipaque was thus a better alternative than Gastrografin in follow-through examinations of intestinal obstruction. Also, 23 patients out of 28 with small bowel obstruction due to peritoneal adhesions, had spontaneous relief of symptoms during the observation period following contrast medium ingestion with no significant difference between the two media. This indicated that enteric follow-through procedures may have a therapeutic efficacy similar to the treatment of small bowel obstruction using nasogastric suction and gastrointestinal rest. Possible mechanisms for this action of the contrast media are discussed.     

The effects of angiographic contrast media on the aggregation and morphology of red cells in vitro

The effects of four angiographic contrast media on the aggregation and morphology of human red cells in vitro, using microscopic observations were studied. The media included an ionic contrast medium, sodium meglumine amidotrizoate (amidotrizoate); non-ionic low-osmolal contrast media, iopamidol and iohexol; and an ionic low-osmolal contrast medium, sodium meglumine ioxaglate (ioxaglate). Strong, large aggregates formed in the control blood, without media, where aggregation of red cells was inhibited by contrast media mixed with the blood in a ratio of 2:1. Almost no aggregates were observed for amidotrizoate, an ionic contrast medium, while there were a few rouleaux formed in the presence of ioxaglate. Nearly all of the red cells aggregated in the presence of iopamidol and iohexol; iohexol produced the greater aggregation of the two. Besides rouleaux, irregular aggregates were formed with iohexol. When the contrast media were mixed with blood in a ratio of 1:2, their inhibitory effects on aggregation declined. These results clearly indicate that contrast media inhibit the in vitro aggregation of red cells, and ionic-contrast media produced more potent inhibitory effects than non-ionic media. With added NaCl and meglumine, iohexol did not induce red cell aggregation. This suggests that ionic-contrast media have greater inhibitory effects on aggregation than non-ionic media, a result of their ionic properties. Red cells were morphologically quite normal in the presence of ioxaglate, where most red cells were crenated in the presence of iopamidol and iohexol, and shrank in the presence of amidotrizoate. In the presence of iopamidol and iohexol with the osmolality adjusted to that of a saline solution, both normal red cells and crenation were observed. This suggests that non-ionic contrast media may directly effect morphological changes in red blood cells. These results revealed that ioxaglate, an ionic contrast medium, was the best in vitro medium, to prevent aggregation of red cells and crenation deformity of erythrocytes.     

Nephrotoxicity of ionic and non-ionic contrast media in aorto-femoral angiography

Nineteen patients examined with aorto-femoral angiography were randomized into two contrast medium groups (meglumine metrizoate and iohexol). Urine activity of beta-hexosaminidase, a specific renal enzyme, was determined before and on three occasions after angiography. No change of beta-hexosaminidase activity was found after angiography with iohexol, while there was a significant increase after examination with meglumine metrizoate. This indicates that meglumine metrizoate even following injection into the abdominal aorta damages renal cells which could not be shown with iohexol as contrast medium. We therefore recommend that at least patients with impaired renal function should be examined with the non-ionic contrast medium iohexol to minimize the danger of further damage to the kidneys and a possible renal failure.     

Cisternography with the non-ionic water-soluble contrast medium metrizamide. A preliminary report.

In 11 patients the basal cisterns in the posterior cranial fossa were examined with the new water-soluble compound metrizamide. Promising results were obtained when the medium was administered suboccipitally or through the foramen ovale but less favourable after lumbar administration. The clinical tolerance of the compound with regard to short term effects was good.     

Effects of ionic and non-ionic paramagnetic contrast media on brain bio-electric activity

The potential neurotoxic effects of gadolinium (Gd)-based compounds for enhanced MRI are not completely understood. We investigated electroencephalography changes induced by ionic and non-ionic Gd-based compounds administered intravenously in patients affected by lesions of the central nervous system (CNS) characterized by breakdown of the blood–brain barrier. This double-blind, randomized, study of two parallel groups involved 40 patients scheduled for an MRI examination with contrast medium for known CNS lesions. Twenty patients were randomly allocated to receive non-ionic Gd-DTPA-BMA/gadodiamide and 20 patients were randomly allocated to receive ionic Gd-DTPA/gadopentetate. For both groups the intravenous dose was 0.1 mmol/kg body weight. Three electroencephalography recordings were performed: immediately before, during, and 15 min after contrast medium injection. Mean and peak frequencies of the beta band and absolute power of the delta and/or theta bands of the electroencephalograms (EEGs) were noted. Each EEG was also evaluated to detect any alterations. The values of the 8–12 Hz band showed a significant increase during and after injection versus baseline in the gadopentetate group (P<0.05) and a significant decrease during injection in the gadodiamide group (P<0.05). The values of the 12–16 Hz band showed a significant increase versus baseline during and after injection in the gadopentetate group (P<0.05). The electrophysiological method based on computerised spectral analysis is a sensitive tool for evaluating effects of contrast media on brain bio-electric activity. EEG changes are detectable, even in the absence of any clinical evidence. It would appear that there might be clinical advantages in the use of non-ionic compounds.     

Effect of bolus administration of non-ionic radiopaque contrast media on blood pressure variation

IntroductionHaemodynamic changes may occur with the rapid intravenous injection of contrast media due to the osmolality of such pharmaceuticals. This study sought to evaluate the effect of bolus administration of intravenous contrast media on blood pressure variation during the Contrast-Enhanced Computed Tomography (CECT) of the abdomen.MethodsThe study included 74 patients who underwent abdominal CECT and they were placed in the first group receiving a maximum of 80 ml of iodinated contrast via pressure injector (4 ml/s). A further 74 patients, who underwent non-contrast enhanced abdominal CT, were placed in the second group in which 80 ml of normal saline was administered via the same manner. Patients with hypertension and who were on anti-hypertensive drugs were excluded from the study. Non-invasive blood pressure was monitored before the injection of contrast media/saline and immediately after the portal venous phase for the CECT scan and after 45 s following the administration of normal saline in the non-contrast CT group. Mean systolic and diastolic blood pressures from both groups were compared to find out the effect of contrast bolus administration on blood pressure variation.ResultsBoth systolic and diastolic blood pressure increased with the injection of contrast media among CECT scan group. No significant changes in systolic and diastolic blood pressure were found before and after the scan in the non-contrast group.ConclusionBolus administration of 80 ml saline has no effect on blood pressure. The increased blood pressure in contrast enhanced studies was induced by the iodinated contrast media and not by the bolus effect.     

Proteinuria following nephroangiography. IV. Comparison in dogs between ionic and non-ionic contrast media.

The degree of albuminuria following hephroangiography with the ionic contrast medium Urografin, the non-ionic Amipaque and a recently synthesized non-ionic contrast medium with the code name C 29 was compared. Significantly less albuminuria was caused by C 29 than by the other two contrast media.     

Effect of radiologic contrast media on cell volume regulatory mechanisms in human red blood cells

RATIONALE AND OBJECTIVES: The authors performed this study to evaluate cell volume regulation in human red blood cells (RBCs) after incubation in solutions of three contrast media: iohexol (830 mOsm), ioxaglate (520 mOsm), and iodixanol (300 mOsm). MATERIALS AND METHODS: Whole blood sampled from six healthy subjects was exposed to Ringer solutions containing 25% or 5% vol/vol iohexol (final osmolality, 440 or 340 mOsm, respectively), ioxaglate (final osmolality, 395 or 335 mOsm, respectively), iodixanol (final osmolality, 330 or 315 mOsm, respectively), or NaCl (control solutions with the same osmolality as that of the contrast media). In some experiments, control RBCs were subjected to a hyposmotic solution (100 mOsm). RBC volumes were obtained with a Coulter counter. RESULTS: The RBCs showed normal regulatory cell shrinkage after hyposmotically induced swelling. All 25% vol/vol contrast material solutions and their control solutions induced RBC shrinkage (range, 6% +/- 1 [standard error] to 22% +/- 3). The same was true for cells exposed to 5% vol/vol contrast material (range, 4% +/- 1 to 7% +/- 1). The shrinkage phase was followed by cell swelling (10% +/- 2 to 20% +/- 2 for 25% contrast material and their control solutions and 8% +/- 1 to 15% +/- 2 for 5% contrast material and their control solutions). No contrast material-exposed RBCs increased their volumes to the level reached with their control solutions. CONCLUSION: RBCs exposed to hyperosmotic iohexol, ioxaglate, or iodixanol solutions shrank and then swelled. The degree of shrinkage and subsequent swelling could not be explained simply with the osmolality of the test solutions. Physicochemical properties of the contrast media must be involved, putatively affecting electrolyte fluxes over the RBC membrane. Possible targets of these effects are the K+/Cl- symporter, K+ channels, and the Na+/K+/Cl- symporter.     

Effect of prostaglandin inhibition on the renal vascular response to ionic and non-ionic contrast media in the dog

In an attempt to study the role of prostaglandins in the renal vascular response to contrast media in mongrel dogs, renal arterial injections of 6 ml of either the non-ionic contrast medium Iopamidol or the ionic medium diatrizoate meglumine/Na+ were performed, before and after intravenous injection of a buffered solution of acetylsalicylic acid (10 mg/kg) (ASA). Renal blood flow was recorded using non-occluding electromagnetic flow probes. The resting renal blood flow was significantly reduced after ASA. The usual biphasic response to contrast injection was observed both before and after ASA, and using either contrast medium. Analysis of the results failed to show any difference in degree of vasodilation or vasoconstriction after ASA. We conclude that prostaglandins may affect the resting level of renal blood flow but are not mediators of the instantaneous changes in response to contrast injection.     

Urinary protein excretion following intravenously administered ionic and non-ionic contrast media in man

Urinary protein excretion following intravenous administration of the radiographic contrast media (CM) diatrizoate (ionic) and iopromide (non-ionic) was examined in 20 patients with normal renal function. Neither of the two CM had any effect on the 24-h urinary excretion of albumin (a marker of glomerular proteinuria). The 24-h urinary excretion of the retinol-binding protein (a marker of low molecular weight or tubular proteinuria) and the folate binding protein, a protein localized in the brush-border membranes of the proximal tubular cells, showed a statistically significant transient increase the day after diatrizoate injection, whereas no increase was observed after iopromide. Thus, only a minimal and temporary disturbance of the renal proximal tubular function was observed after diatrizoate injection in patients with normal renal function.     

Comparison of intravenous drip infusion excretory urography using ionic and non-ionic contrast media

Ionic and non-ionic contrast media were compared for use in intravenous drip infusion excretory urography. Sixty consecutive cases were classified alternately into two groups, ionic and non-ionic, excluding cases which were known to have factors affecting contrast ability adversely, such as hydronephrosis, renal failure and so on. Each group consisted of 30 cases. A hundred ml of the ionic contrast medium (Diatrizoate--60% Urografin) or non-ionic contrast medium (Iopamidol--Iopamiron 300) was administered I.V. by drip infusion, each infusion taking less than 10 minutes, using a 18 G needle, and 0-minute, 10-minute and 20-minute films were obtained. Visibility of nephrogram, calyceal system, renal pelvis, ureters and bladder were evaluated, ranging from 0 to 3, by six radiologists who were not informed of the contrast medium used. Some detailed factors such as radiographic contrast and fullness of the collecting system and of the bladder were also analyzed. Visualization rate of the ureters was defined as the length of visualized ureters divided by the distance between the renal pelvis and the ureteral orifice of the bladder. There was no significant difference in visualization of nephrogram between the two groups. However, the non-ionic group was superior to the ionic group in visualization of the calyceal system and ureters with statistical significance, probably due to higher radiographic contrast of non-ionic medium. There was no statistical significance between the two groups, in fullness of the calyceal system and visualization rate of the ureters, whereas the ionic group was superior to the non-ionic group in fullness of the bladder.(ABSTRACT TRUNCATED AT 250 WORDS)     

Renal contrast radiography study in hypertensive patients: comparison of the nephrotoxicity of ionic and non-ionic contrast media

The results of a study carried out on 32 patients with arterial hypertension about nephrotoxic effect obtained with a new non-ionic contrast agent have been reported. The diagnostic approach was based on the determination of the urinary excretion of two characteristic enzymes of the proximal tubule-epithelial cells (alfa-glycosidase and gamma-glutamil-transferase) and of a microprotein (beta-2-microglobulin) filtered by glomeruli and readsorbed and catalized by epithelial cells. The method used show an increased sensitivity and reliability in the early recognition of a kidney damage as well as in the control of anatomic and functional changes, in comparison with the classic parameters (azotemia, creatininemia). The results show a significantly lower enzymuric and microproteinuric level using non-ionic contrast media, also, in the patients at relatively higher risk of kidney damage. This results should be interpreted in favour to a lower potential nephrotoxicity of non-ionic contrast media and their elective use in the patients with a higher risk of kidney damage.     

Reaction to contrast media in contrast-enhanced CT of the brain. A comparative investigation of non-ionic ultravist and ionic urografin-meglumin

A comparison has been made of contrast medium reactions in contrast-enhanced CT of the cerebrum using Urografin-meglumin and a new non-ionic, low-osmolality radiologic contrast medium, Ultravist. The number of contrast medium reactions was significantly less with Ultravist, but many mild reactions were observed with both contrast media. Regardless of the contrast used, the incidence of contrast reactions was independent of the CT diagnoses.