Kinetics of intravenous radiographic contrast medium injections as used on CT: simulation with time delay differential equations in a basic human cardiovascular multicompartment model.

Objectives: To develop a multicompartment model of only essential human body components that predicts the contrast medium concentration vs time curve in a chosen compartment after an intravenous injection. Also to show that the model can be used to time adequately contrast-enhanced CT series.

Methods: A system of linked time delay instead of ordinary differential equations described the model and was solved with a Matlab program (Matlab v.

Kilovoltage dependence of the attenuation of a potassium iodide/water solution on CT: presentation of a computer model implementing polychromatic character of the X-ray photon beam.

Purpose: To describe a program that simulates a computed tomographic scan with the polychromatic aspect of the output of the x-ray tube implemented. This program can be used in the study of the attenuation of different solutions/solutes. These results can subsequently guide the radiologist to obtain a satisfying contrast enhancement at lower tube voltages and eventually lower contrast volumes.

Stabilization of the hydrophilic sphere of non-ionic monomers: are all protected in a similar way?

The present study attempts to investigate whether incorporation of a methyl group as second substituent in the tertiary amido group of the two benzamide side chains of iobitridol (Xenetix) increases the stability of the hydrophilic sphere around this molecule as claimed by its manufacturer, and whether this hydrophilic sphere is unique to this particular molecule or to what extent other monomer non-ionic contrast media show this feature. Five non-ionic monomer contrast medium molecules, ioversol, iohexol, iobitridol, ioxilan and iopromide, were studied. Barriers to the rotation of acetanilide and benzamide side chains, and to the rotation of the amide bond in the benzamide chains, were calculated at a semi-empirical quantum mechanical level of theory with the Mopac/Ampac computer program.

Renal failure and iodinated contrast media. A review.

Contrast medium-induced renal failure is reported to be a very frequent adverse effect (up to 70% incidence) that often goes undetected. Consequences are sometimes very dramatic and can even lead to irreversible renal damage and renal dialysis. Basically, four groups of mechanisms will be considered: decrease of renal perfusion and increased vascular resistance, glomerular injury, tubular injury, and obstructive nephropathy.

Multiple regression analysis of octanol/water partition coefficients of non-ionic monomeric radiographic contrast media with the combination of three molecular descriptors.

A multiple non-linear regression equation is calculated for the correlation of the octanol/water partition coefficient of nine non-ionic monomeric radiographic contrast media molecules with a combination of three molecule describing parameters (heat of formation, dipole and ovality). Good correlation is obtained (proportion of variance explained, R2, is 0.9093).

Analysis of the factors influencing the osmolality of eight monomeric nonionic iodinated contrast medium molecules.

Rationale And Objectives: Because the measured osmolality of a contrast medium solution differs considerably from the theoretical one, the author analyzed the relative influence of various parameters on the experimental osmolality and derived an equation permitting the prospective calculation of the real osmolality of monomeric nonionics. The author discusses the consequences of the results.

Materials: Eight monomer nonionic iodinated molecules (ioversol, iohexol, P-569, iobitridol, P-530, iopamidol, and iopromide) were analyzed.

Computation of the solvent-accessible surface area of monomer nonionic contrast media. Consequences for used probe radius in the study of hydrophilic characteristics.

Rationale And Objectives: The solvent-accessible surface areas of different monomer nonionic contrast media were calculated for different probe radii. By correlating these areas with an experimental (octanol/water partition coefficient) and a calculated parameter (COMB-C), implications for the radius of the probe volume are pointed out.

Methods: The solvent-accessible surface areas of seven monomer nonionic iodinated contrast media were calculated with GEPOL (a program able to calculate various molecular surfaces and volumes) for a wide range of probe radii of the solvent.

Application of the lateral/facial protection model to a new molecule, iobitridol.

Rationale And Objectives: The author applies the model quantifying lateral/facial protection of the benzene ring of monomer nonionic contrast media molecules to a new molecule, iobitridol, to confirm the validity of the model and the importance of the facial/lateral protection in the design theory.

Materials And Methods: A tridimensional model of iobitridol was built, the appropriate measurements were taken, and the previously proposed parameter, COMB-C, was calculated. With the linear regression equation calculated on the basis of the data of six other molecules (and COMB-C as the independent variable), the log-p was calculated prospectively and compared with the known experimental log-p.

Correlation of some geometric parameters derived from molecular models of monomer nonionic contrast medium molecules with their octanol/water partition coefficient.

Rationale And Objectives: The author geometrically quantifies the concept of hydrophilic facial and lateral protection of the benzene ring in nonionic monomer contrast medium molecules and verifies the validity of its incorporation in the design theory. The author also correlates this quantification with the octanol/water partition coefficient.

Methods: Six monomer nonionic contrast medium molecules were studied using simple measuring techniques with respect to some geometric parameters quantifying the hydrophilic protection of the hydrophobic zones.

Bleeding from the lateral circumflex artery following total hip replacement, treated by embolization.

A patient with bleeding from the lateral circumflex artery following total hip replacement was successfully treated by embolization. The mechanism of injury and treatment modalities are discussed.

The (in)compatibility of drugs and contrast media: a review of the literature.

This report presents a concise review of the available literature on the (in)compatibility of commonly used contrast media and equally well known drugs. The importance of avoiding injection of a medication that, when mixed with a contrast agent, does flocculate or precipitate is stressed.

Adrenal cortical carcinoma: a case report.

We present a case of adrenocortical carcinoma. Excretory urography and sonography revealed a left adrenal mass, which was confirmed by computer tomography and further delineated by arteriography. Complete surgical resection was possible.

Traumatic rupture of the ascending aorta: a case report.

A patient with a rupture of the ascending aorta after a non-penetrating chest trauma is presented. The aortic tear, angiographically demonstrated, was situated just above the left coronary ostium. Only three examples of angiographically established cases of rupture of the ascending aorta were found in the literature.