Non-ionic Contrast Medium Iohexol Research Articles

Fluid transport in porous media based on differences in filter media morphology and biofilm growth in bioreactors

To elucidate the effect of pore structure on bioclogging and seepage flow in bioreactors, we used X-ray computed tomography (X-CT) to investigate the changes in seepage flow of porous media in zeolite, gravel and ceramsite bioreactors with biofilm growth by injecting a non-ionic contrast medium iohexol. Based on the X-CT images using a ball-and-stick model, the highest average pore radius (R‾) and the average pore throat radius (r‾) in the ceramsite column were found under the initial conditions, which facilitated its permeability. The pore and throat of the gravel column were small and homogeneous relatively. Biofilm growth decreased the pore and pore throat in the columns. The total throat area of zeolite, gravel and ceramsite columns declined by 74%, 73% and 79% respectively. The zeolite column had the highest average pore throat, which contributed to its maximum conductivity subsequently after biofilm growth. Further, the fractal dimensions of the pore structure increased with biofilm growth, especially in the zeolite and ceramsite columns. The heterogeneity of the porous media was reinforced by the biofilm growth in the zeolite and ceramsite columns due to their higher heterogeneity initially. We also observed that an increase in heterogeneity of porous medium amplified the preferential flow and flow heterogeneities, especially in the zeolite and ceramsite columns.

Drug eruption caused by the nonionic contrast medium iohexol. “Recall‐like phenomenon” appearing on an area previously affected by herpes zoster

We report a case of "recall-like phenomenon" caused by nonionic contrast medium. A 62-year-old woman suffering from postherpetic neuralgia developed erythematous plaques 12 h after an intercostal nerve block under X-ray guidance using iohexol (Omnipaque) as contrast medium. The erythematous plaques were preferentially located in the sites where she had experienced herpes zoster 4 months previously. The lesions cleared spontaneously leaving no pigmentation. Both patch testing and intradermal testing with iohexol and ioversol were positive. We postulate that local immunological changes in the skin, such as an increased number and/or accelerated activity of Langerhans cells and mast cells in the herpes zoster lesions, were responsible for this phenomenon. This "recall-like phenomenon", occurring preferentially in skin previously affected by herpes zoster, could facilitate understanding of the pathology of drug eruptions.

Contrast media as markers of GFR.

Determination of the glomerular filtration rate (GFR) is generally considered as the most important parameter of quantifying renal function. The GFR is determined as renal or plasma clearance of an ideal filtration marker which is freely filtered by the kidney, does not undergo metabolism, tubular secretion or absorption. Markers that fulfil these demands are inulin, 51Cr-EDTA, 99mTc-DTPA, labelled or unlabelled contrast media. The renal clearance of inulin is the classic reference method for estimation of the GFR. This method is however not practical for routine clinical purposes. Radionucleids have therefore been used as alternative filtration markers since the 60s. Drawbacks related to radiation exposure especially in children and pregnant women and the safety in handling radiolabelled markers have led to an increasing interest in using non-radioactive markers. The development of simple and reliable methods to determine the concentration of contrast media in plasma and urine, such as high-performance liquid chromatography (HPLC) and X-ray fluorescence analysis have made this possible. The non-ionic low osmolar contrast medium iohexol has become the most commonly used contrast medium for GFR measurements in Europe. However, other contrast media with similar pharmacokinetics may be equally suitable as GFR markers.

Pheochromocytoma: effect of nonionic contrast medium in CT on circulating catecholamine levels.

To study the catecholamine-releasing effect of peripheral intravenous administration of the nonionic contrast medium iohexol in patients with pheochromocytomas. Ten patients (eight women, two men; mean age, 44 years; age range, 25-70 years) with pheochromocytomas and related tumors and six healthy volunteers (five men, one woman; mean age, 31 years; age range, 27-35 years) were examined. Plasma catecholamine levels were measured at intervals for 60 minutes after the injection of 0.9% saline or iohexol on 2 separate days. All 10 patients intravenously received the specific alpha-adrenergic blocker phenoxybenzamine hydrochloride (0.5 mg/kg in 250 mL of 5% dextrose infused over 2 hours) 24 hours before iohexol-enhanced computed tomography. There was no statistically significant increase in epinephrine or norepinephrine levels in the patients or the control subjects. While it may be prudent to administer oral alpha- and beta-adrenoceptor antagonists in all patients with a biochemically proved pheochromocytoma to control their symptoms and to prevent a spontaneous adrenergic crisis, specific blockade may not be required before contrast medium-enhanced scanning with iohexol. Although the sample size of this study is relatively small, the results do suggest that in an incidentally detected, clinically silent adrenal mass that may or may not be hypersecreting, the nonionic contrast medium iohexol may be used for scanning without blockade.

Fibrinopeptide A, Prothrombin Fragment 1 + 2, Thrombin-Antithrombin Complex and D Dimer before and after Injection of a Nonionic Contrast Medium (lohexol)

The principal aim of this study was to evaluate, on biochemical grounds, whether injection of a low-osmolar nonionic contrast medium (iohexol) can induce a prothrombotic state and/or a change in fibrinolysis. Fifteen patients were submitted to urographic examination and the assays listed below were performed: before the injection (T0), 1 h after (T1), and 24 h after (T24) the injection of the contrast medium. The following assays were performed: fibrinopeptide A (FPA), prothrombin fragment 1+2 (F1+2), thrombin-antithrombin complex (TAT) and D dimer (D-D). The assays were carried out on 6 of the patients to whom a saline infusion was administered. Only a mild statistically significant increase was found in FPA levels at 1 h after injection of the contrast medium (mean and CI 95%: T0 4.4, 3.7-5.5; T1 6.0, 4.9-9.1; p = 0.003). F1+2, TAT and D-D did not show any significant change after the injection. These findings show that after injection of iohexol, only a mild, though statistically significant, increase in FPA levels was observed as an expression of increased thrombin activity. In the absence of any significant increases in TAT, F 1+2 and D-D, we have no evidence of a prethrombotic state.

The effect of the non-ionic contrast medium iohexol on glomerular and tubular function in diabetic patients.

The effect of the non-ionic contrast medium iohexol (Omnipaque) on renal function was investigated in diabetic patients with signs of peripheral ischaemia. Forty-six patients, 70 +/- 11 years (mean +/- SD) old, age at diabetes diagnosis 53 +/- 17 years, and with varying degrees of diabetic nephropathy were studied before 1, 2, and 30 days after aortobifemoral arteriography. Serum creatinine, creatinine clearance, urinary excretion of immunoglobulin G, albumin collagen IV (NC1), kappa and lambda chains, alpha-1 microglobulin and Tamm-Horsfall protein were evaluated. Within 1 month before and 30 days after arteriography, the glomerular filtration rate was measured by clearance of iohexol. The acute effect of the radiocontrast medium was an increase in the serum creatinine level in 41 (89%) patients, with a more than 25% increase in 12 (26%) patients. The excretion rates of immunoglobulin G and albumin decreased, whereas the proximal and distal tubular function and the excretion of collagen IV did not change. The increment in serum creatinine was associated with the preangiographic renal function (p < 0.05), a history of heart failure (p < 0.01), but not with age, duration and type of diabetes, gender, systolic or diastolic blood pressure, glycated haemoglobin (HbAlc) or blood glucose levels. The increase of serum creatinine was associated with a pre-existing proximal tubular dysfunction and a worsening of distal tubular function. No changes in the parameters measured persisted 30 days after angiography. In summary, a transient increment in serum creatinine level after arteriography occurred in 89% of diabetic patients. It was associated with the preangiographic renal function, a history of heart failure and signs of preexisting proximal tubular dysfunction and worsening of distal tubular function. However, these changes were reversible.

The Effect of the Non‐ionic Contrast Medium Iohexol on Glomerular and Tubular Function in Diabetic Patients

The effect of the non-ionic contrast medium iohexol (Omnipaque®) on renal function was investigated in diabetic patients with signs of peripheral ischaemia. Forty-six patients, 70 ± 11 years (mean±SD) old, age at diabetes diagnosis 53±17 years, and with varying degrees of diabetic nephropathy were studied before, 1, 2, and 30 days after aortobifemoral arteriography. Serum creatinine, creatinine clearance, urinary excretion of immunoglobulin G, albumin, collagen IV (NC1), kappa and lambda chains, alpha-1-microglobulin and Tamm-Horsfall protein were evaluated. Within 1 month before and 30 days after arteriography, the glomerular filtration rate was measured by clearance of iohexol. The acute effect of the radiocontrast medium was an increase in the serum creatinine level in 41 (89 %) patients, with a more than 25 % increase in 12 (26 %) patients. The excretion rates of immunoglobulin G and albumin decreased, whereas the proximal and distal tubular function and the excretion of collagen IV did not change. The increment in serum creatinine was associated with the preangiographic renal function (p<0.05), a history of heart failure (p<0.01), but not with age, duration and type of diabetes, gender, systolic or diastolic blood pressure, glycated haemoglobin (HbAlc) or blood glucose levels. The increase of serum creatinine was associated with a pre-existing proximal tubular dysfunction and a worsening of distal tubular function. No changes in the parameters measured persisted 30 days after angiography. In summary, a transient increment in serum creatinine level after arteriography occurred in 89 % of diabetic patients. It was associated with the preangiographic renal function, a history of heart failure and signs of preexisting proximal tubular dysfunction and worsening of distal tubular function. However, these changes were reversible.

Contrast Enhancement of the Upper Abdomen Evaluated BY CT

The non-ionic monomeric contrast media iopamidol and iohexol were compared concerning enhancement in the organs of the upper abdomen in CT. The average peak enhancement above the base line for the 2 contrast media in the liver, vena cava, aorta and spleen was calculated. No difference between the contrast media was found with regard to increase in contrast enhancement. No correlation between the peak enhancement and body weight and body surface was found with either of the 2 contrast media.

A Rare Case of Disseminated Intravascular Coagulation Caused by the Nonionic Contrast Medium Iohexol

A Rare Case of Disseminated Intravascular Coagulation Caused by the Nonionic Contrast Medium Iohexol

A Rare Case of Disseminated Intravascular Coagulation Caused by the Nonionic Contrast Medium Iohexol

Nonionic contrast media are reported to cause serious adverse reactions less often than ionic contrast media. However, we treated an otherwise healthy woman with a left ureteral stone in whom disseminated intravascular coagulation developed due to intravenous administration of the nonionic contrast medium iohexol. We discuss the clinical course and possible causes of disseminated intravascular coagulation. Our case emphasizes that nonionic contrast media are not free from serious adverse reactions although the incidence seems extremely low.

Effects on Erythrocyte Aggregation and Blood Coagulation from Iohexol Solutions with and without Sodium Chloride

Solutions of the nonionic monomeric contrast medium iohexol (300 mg I/ml) with and without added NaCl were investigated for effects on red blood cell aggregation and blood coagulation. Three volumes of a test solution were mixed in test tubes with one volume of human blood. During 30 min samples of the mixture were taken for investigation. Six test solutions were used: 1) iohexol, 2) iohexol+glucose 280 mM, 3) iohexol+NaCl 150 mM, 4) glucose 280 mM, 5) glucose 140 mM+NaCl 75 mM, 6) NaCl 150 mM. Test solutions with NaCl caused no aggregation. Test solutions without NaCl always caused macroscopic red cell aggregates. These aggregates always disappeared when saline was added to the sample. The macroscopic red cell aggregates could be dispersed to microscopic aggregates by shaking the test tubes. During the next 30 min macroscopic aggregates returned in the glucose solution but not in the iohexol solutions. In 30 min, blood mixed with iohexol solutions never coagulated while blood layered on top of the same iohexol solutions always coagulated. Blood mixed with solutions 5 and 6, both without iohexol, always coagulated. It is concluded that adding 150 mM NaCl to iohexol did not eliminate its ability to antico-agulate whole blood, but inhibited its ability to aggregate red cells. This inhibition was not caused by the osmotic effects of the added NaCl.

Effects on Erythrocyte Aggregation and Blood Coagulation from Iohexol Solutions with and without Sodium Chloride

Solutions of the nonionic monomeric contrast medium iohexol (300 mg I/ml) with and without added NaCl were investigated for effects on red blood cell aggregation and blood coagulation. Three volumes of a test solution were mixed in test tubes with one volume of human blood. During 30 min samples of the mixture were taken for investigation. Six test solutions were used: 1) iohexol, 2) iohexol+glucose 280 mM, 3) iohexol+NaCl 150 mM, 4) glucose 280 mM, 5) glucose 140 mM+NaCl 75 mM, 6) NaCl 150 mM. Test solutions with NaCl caused no aggregation. Test solutions without NaCl always caused macroscopic red cell aggregates. These aggregates always disappeared when saline was added to the sample. The macroscopic red cell aggregates could be dispersed to microscopic aggregates by shaking the test tubes. During the next 30 min macroscopic aggregates returned in the glucose solution but not in the iohexol solutions. In 30 min, blood mixed with iohexol solutions never coagulated while blood layered on top of the same i...

Cerebral Thromboembolic Complications Associated with the Use of a Nonionic Contrast Medium in Coronary Angiography

Cerebrovascular complications were registered in 11 patients (0.21%) of 5,339, consecutively submitted to coronary angiography with the nonionic contrast medium iohexol (Omnipaque). Six of the patients had diseases predisposing them to thromboembolic complications, 3 of whom earlier had symptoms of cerebral stroke. Excluding these 6, the incidence of cerebral thromboembolic events was 0.10% in patients with no predisposing diseases. Precise catheterization technique and some anticoagulation and antiplatelet activity therapy are definite precautions against these complications, while the role of the contrast medium is still debated.

Effects on Erythrocyte Aggregation and Blood Coagulation from Iohexol Solutions with and without Sodium Chloride

Solutions of the nonionic monomeric contrast medium iohexol (300 mg I/ml) with and without added NaCl were investigated for effects on red blood cell aggregation and blood coagulation. Three volumes of a test solution were mixed in test tubes with one volume of human blood. During 30 min samples of the mixture were taken for investigation. Six test solutions were used: 1) iohexol, 2) iohexol+glucose 280 mM, 3) iohexol+NaCl 150 mM, 4) glucose 280 mM, 5) glucose 140 mM+NaCl 75 mM, 6) NaCl 150 mM. Test solutions with NaCl caused no aggregation. Test solutions without NaCl always caused macroscopic red cell aggregates. These aggregates always disappeared when saline was added to the sample. The macroscopic red cell aggregates could be dispersed to microscopic aggregates by shaking the test tubes. During the next 30 min macroscopic aggregates returned in the glucose solution but not in the iohexol solutions. In 30 min, blood mixed with iohexol solutions never coagulated while blood layered on top of the same iohexol solutions always coagulated. Blood mixed with solutions 5 and 6, both without iohexol, always coagulated. It is concluded that adding 150 mM NaCl to iohexol did not eliminate its ability to anticoagulate whole blood, but inhibited its ability to aggregate red cells. This inhibition was not caused by the osmotic effects of the added NaCl.

Cardiac Effects of Adding Electrolytes and Oxygen to Iohexol in a Dog Model of Contrast Media-Induced Ventricular Fibrillation

We investigated whether addition of a balanced electrolyte supplement and oxygen to the nonionic contrast medium iohexol reduces the risk of ventricular fibrillation (VF), and studied regional electrophysiology prior to the VF event. Twenty ml of each test solution were infused at a rate of 0.5 ml/s into the left anterior descending coronary artery (LAD) in 8 anesthetized dogs. LAD was externally occluded during infusion, to simulate a wedged catheter situation. ECG, hemodynamics, regional epicardial monophasic action potential duration (MAPD) and ventricular activation times (VAT) were calculated. All infusions with iohexol caused VF within 27 s. Five of 12 infusions with iohexol + 30 mmol NaCl, 3 of 11 infusions with iohexol+electrolytes (IPE) NaCl, KCl, CaCl2 and MgCl2) and 4 of 11 infusions with IPE with oxygen addition (IPE+O2) caused VF after 45 s. Iohexol did not change MAPD prior to the VF event. Iohexol + 30 mmol NaCl and the IPE solutions lengthened MAPD initially, but at the time of the VF event MAPD were normalized or shortened. We conclude that electrolyte supplement to iohexol may prevent VF, probably by lengthening MAPD.

Cardiac Effects of Adding Electrolytes and Oxygen to Iohexol in a Dog Model of Contrast Media-Induced Ventricular Fibrillation

We investigated whether addition of a balanced electrolyte supplement and oxygen to the nonionic contrast medium iohexol reduces the risk of ventricular fibrillation (VF), and studied regional electrophysiology prior to the VF event. Twenty ml of each test solution were infused at a rate of 0.5 ml/s into the left anterior descending coronary artery (LAD) in 8 anesthetized dogs. LAD was externally occluded during infusion, to simulate a wedged catheter situation. ECG, hemodynamics, regional epicardial monophasic action potential duration (MAPD) and ventricular activation times (VAT) were calculated. All infusions with iohexol caused VF within 27 s. Five of 12 infusions with iohexol + 30 mmol NaCl, 3 of 11 infusions with iohexol + electrolytes (IPE) (NaCl, KCl, CaCl2 and MgCl2) and 4 of 11 infusions with IPE with oxygen addition (IPE + O2) caused VF after 45 s. Iohexol did not change MAPD prior to the VF event. Iohexol + 30 mmol NaCl and the IPE solutions lengthened MAPD initially, but at the time of the VF event MAPD were normalized or shortened. We conclude that electrolyte supplement to iohexol may prevent VF, probably by lengthening MAPD.

Effects of vasoconstrictors on rabbit coronary arteries exposed to iohexol with addition of electrolytes (sodium and calcium).

A well-known side effect of contrast media (CM) is vasodilation. Different types of CM in vitro inhibit the action of vasoconstrictors to various degrees. The nonionic CM iohexol inhibits the action less than ionic CM. In this study, the authors investigate whether the addition of electrolytes to iohexol causes less inhibition of the vasoconstrictors. Vasoconstriction dependent on potential-operated calcium channels (POCs) (potassium chloride), or receptor-operated calcium channels (ROCs) (histamine, endothelin-1, and prostaglandin F2 [PGF2 alpha]) was specifically studied. Segments of rabbit coronary arteries were mounted between two L-shaped prongs in tissue baths with buffer solution or solutions of iohexol (140 mg I/mL) with addition of different concentrations of NaCl and CaCl2. The responses of the vessels to increasing concentrations of a vasoconstrictor were examined. Concentration of vasoconstrictor versus contractile response curves were plotted, and the maximal contraction of the vasoconstrictor (Emax) and half maximal constriction were calculated. Addition of 30 mM NaCl and 1.5 mM CaCl2 caused a vasoconstriction to KCl in iohexol almost identical to its vasoconstriction in buffer. Higher concentrations of NaCl caused decreasing Emax of all vasoconstrictors. The inhibition of the ROC-dependent vasoconstrictors could not be normalized by the addition of electrolytes. The inhibition of the POC-dependent vasoconstrictor was caused by "ion toxicity" of iohexol. The inhibition of the ROC-dependent vasoconstrictors was caused by other mechanisms, in a manner compatible with a blocking effect on ROCs.

Addition of Sodium to Iohexol

The addition of sodium to nonionic contrast media has reduced the incidence of arrhythmias in animal models. The influence on cardiac function and safety of sodium addition to the nonionic contrast medium iohexol (Omnipaque) was studied in a randomized, double-blind trial in patients undergoing cardioangiography. Fifty-nine patients received iohexol 350 mg I/ml with NaCl 28 mmol/l and 58, iohexol only. ECG changes after contrast injections were evaluated with continuous computerized dynamic vectorcardiography (VCG). QRS-vector difference (QRS-vd), which reflects changes in the QRS-complex, was chosen as the main parameter. Both contrast media caused changes in the QRS-complex, but there was no significant difference between the two. No serious arrhythmias were observed. Both contrast media were well tolerated. No beneficial effects from enriching iohexol with sodium were found. VCG was found to be a valuable tool in the study of contrast medium-induced ECG changes.

In Vivo Fluorescence Microscopy of Microcirculation in the Renal Cortex of Mice

In vivo fluorescence microscopy was used for experimental studies of the renal cortical microcirculation in normal mice and in mice pretreated with the nephrotoxic drug cyclosporin A. The cortical circulation was studied after i.v. infusions of a nonionic low osmolar contrast medium (iohexol) and after infusions of mannitol. All infusions produced marked effects on the distribution and velocity of cortical blood flow with no differences between iohexol and mannitol. The renal cortical blood flow was inhomogeneous regarding different capillaries and there was an initial rise in the number of capillaries with increased blood flow after infusions of both mannitol and iohexol. There was simultaneously an increased number of capillaries with decreased blood flow following all infusions. The decreased blood flow after infusion of iohexol was more pronounced when the animals had been pretreated with cyclosporin A. The difference was only significant (p < 0.05) during a short part of the observation period of 30 min, but it may indicate that kidneys previously exposed to cyclosporin A are more susceptible to infusions of iohexol.

Does the Administration of Systemic Radiographic Contrast Media Influence the Acute Changes in Renal Physiology Following Exposure to Extracorporeal Shock Waves in Dogs?

Five anesthetized dogs were studied for 4 to 5hours after administration of extracorporeal shock waves to one kidney, the contralateral organ serving as control. Repetitive major doses of the nonionic monomeric radiographic contrast medium (CM) iohexol were injected intravascularly before and after application of the extracorporeal shock waves for further provocation of kidney function. Urinary excretion of electrolytes, N-acetyl-β-glucosaminidase (NAG) and kallikrein, clearances of creatinine, inulin and para-amino-hippuric acid (PAH), serum aldosterone level and plasma renin activity (PRA) were determined.On the exposed side there was a significant fall in urinary osmolality. Effective renal plasma flow (ERPF) was reduced and glomerular filtration rate (GFR) was unchanged; thus filtration fraction (FF) was increased. Extraction of PAH was reduced, and true renal plasma flow was unchanged.Urinary osmolality on the control side was unchanged. There was a fall in ERPF and increased GFR; therefore, FF increased.The mean rise of PRA in the exposed kidney was significant after shock waves. Urine volume and urinary excretion of electrolytes and kallikrein were stable bilaterally.Relating the results to those obtained in identical canine experiments without CM, simultaneous administration of CM does not seem to significantly influence the changes in kidney function parameters caused by extracorporeal shock waves in the dog.