CH712511B1 - X-ray contrast media for postmortem, experimental and diagnostic angiography. - Google Patents

Abstract

The invention relates to a contrast agent for angiography for the examination of animal or human bodies or components such as limbs or organs thereof containing a substantially oil-based apolar contrast component for X-ray examinations, wherein the contrast component has a contrast component viscosity in the range of 30-100 mPas. The contrast agent is characterized in that the contrast component is present in a mixture with at least one further apolar component whose viscosity is lower or at most equal to the contrast component viscosity. In addition, the invention relates to a method for angiographic examination of animal or human bodies or organs, components such as limbs thereof, in which such a contrast agent is used at least in periods, or a use of such contrast agents for angiographic examination of animal or human bodies or organs, Components like limbs thereof.

Description

Description Technical Field The present invention relates to a contrast agent for postmortem angiography, in particular for the examination of animal or human bodies or components thereof, e.g. of limbs or organs. The contrast agent contains a substantially oil-based, apolar contrast component, as used for X-ray examinations, wherein the contrast component has a contrast component viscosity in the range of 30-100 mPas. Furthermore, the invention relates to angiographic methods in which such a contrast agent is used at least during periods of time.

Background Art Angiography is the imaging of blood vessels by X-rays. For this purpose, a contrast agent, i. H. a substance which is hardly permeable to X-rays is injected into the blood vessel. The vascular interior filled with contrast medium then becomes visible on the X-ray image. The resulting image is called angiogram. In the medical language, the long word angiography is often abbreviated to the word angio. Among other things, computer tomography can be used for angiography.

The computed tomography, abbreviation CT, is the computer-aided evaluation of a variety recorded from different directions X-ray images of an object to produce a three-dimensional image (Voxeidaten). It is an imaging process.

The presently in use techniques for imaging vascular examination can be divided into groups of methods: on the one hand, pouring techniques are available, on the other hand, there are contrast agents that are able to penetrate capillaries. A general review of all techniques of postmortem angiography can be found in "Postmortem Angiography - A Review of Former and Current Methods" (S. Grabherr et al., AJR 2006 in press).

Pouring techniques: For example, methyl methacrylates (for example Mercox®) or Microfil® are used in the pouring techniques. These substances are injected freshly after prior rinsing of the vessels. After curing, the tissue is macerated away, lasting 2-4 weeks. What remains is then the spout of the vessels, which can be examined by the naked eye, by means of a microscope or electron microscope or also by means of X-ray techniques (see Djonov et al., Anal Embryo / 2000, 202: 347-357). Disadvantages of this method are the elaborate preparation of these preparations, the long period of time that requires maceration and not least the high risk of damage to the preparations by maceration and the subsequent handling, in which very small pieces of the drug can break off.

Liquid Contrast Agents: Most liquid contrast media are not suitable for microangiographies. Water-based mixtures have the property of leaving the vessels very quickly by penetration through the vessel wall (so-called extravasation), which leads to blurred contours of the vessels shown. Also, their contrast is not high enough to clearly represent small vessels such as capillaries.

Oily contrast agents have the property of remaining within the vessels without penetrating the vessel wall (usually no extravasation). This leads to a clearly contoured representation of the vessels. However, there is no Kapillargängigkeit due to occlusions occurring in the so-called capillaries.

Corpuscular contrast agents can be used when using small corpuscular particles for microangiography. The best known contrast agent is Micropaque®. However, when used in combination with micro-CT devices, the problem of precipitating the solute particles has been described, resulting in artifacts (M Marxen et al., Med Phys. 2004, 31: 305-313). Marxen clearly describes in his paper the necessity and the lack of a suitable contrast medium for microangiography by means of micro-CT.

DESCRIPTION OF THE INVENTION Accordingly, the object of the invention is to provide an improved contrast medium for imaging methods of the type mentioned at the outset. In particular, it is concerned with the improvement of a contrast agent for angiography, for example for the examination of animal or human bodies or components thereof, e.g. of limbs (which may also be on the body), containing a substantially apolar (in other words, almost impossible or not miscible with water), that is usually oil-based, contrast component for X-ray examinations. The contrast component has a relatively high viscosity in this type, typically in the range of 30-100 mPas.

The problem with such apolar oily contrast components is the fact that they have a high viscosity. This high viscosity leads to the fact that the contrast component can not penetrate arbitrarily in capillaries and accordingly also not be able to fully image the blood vessel system. In addition, it can even lead to a proper blockage of capillaries and sections. The advantage of the essentially non-existent extravasation is thereby reversed in many applications.

Surprisingly, it was found that it is possible with such contrast components to use them with great advantage in a mixture. The mixture is characterized in that the contrast component is present in a mixture with at least one further apolar component whose viscosity is lower or at most equal to the contrast component viscosity. The admixing of this further apolar component will be used, on the one hand, to adjust the viscosity to the desired value, for example to the value of blood. On the other hand, it is used to act as a carrier for the contrast component without altering its extravasation properties. This was unexpected in particular in view of the fact that the positive properties regarding extravasation can be maintained and yet the viscosity of the entire mixture can be adjusted to an optimum value, and despite the dilution of the contrast component, an excellent contrast is possible.

A first preferred embodiment is characterized in that the further apolar component is a substantially saturated, branched, unbranched, or cyclic hydrocarbon, or a mixture of such hydrocarbons. Preferably, the further apolar component is an alkane (preferably n-alkane, isoalkane) or a mixture of alkanes having a number of carbon atoms in the range of 5-45, particularly preferably in the range of 12-30.

For example, it is possible to admix an apolar component having a comparatively low viscosity, such as an alkane with 12-18, preferably 14-16 carbon atoms, or a mixture of such alkanes, which is particularly preferably a n-alkane or a mixture of such n-alkanes. In particular, tetradecane or hexadecane are preferred, but it is also possible to use systems such as cyclohexane or mixtures such as, for example, petroleum or even petroleum ether. Preferred systems have a melting point above 0 ° C and / or a boiling point of at least 200 ° C.

A further preferred embodiment is characterized in that the further apolar component is a component with a rather higher viscosity (but still at most equal to or greater than that of the contrast component), for example an alkane, in particular a n-alkane or an iso-alkane, with 20-30 carbon atoms. Preferred compounds are e.g. paraffin oil, especially preferably paraf-finum perliquidum. The apolar component with a rather higher viscosity may also be a vegetable oil, for example a methylated rapeseed oil or similar vegetable oils.

An additional preferred embodiment is characterized in that the contrast component has a viscosity in the range of 30-80 mPas. Thus, for example, the angiography in the contrast component is preferably an iodine-based or sulfur-based X-ray contrast agent, more preferably an iodinated or brominated component or especially oil, for example, a propyliodone, a fatty acid ethyl ester of iodinated poppy seed oil (eg Lipiodol), or lodipine, wherein it is particularly preferably lipiodol ultrafluid.

A very particularly preferred embodiment of the mixture is characterized in that the further apolar component has a viscosity which is lower than the contrast component viscosity. Thus, the further apolar component preferably has a viscosity in the range of 0.2-80 mPas, preferably in the range of 2-60 mPas.

As already explained, it is possible to admix an apolar component having a comparatively low viscosity, so preferably having a viscosity in the range of 1-10 mPas, preferably in the range of 2-4 mPas. Alternatively, or more preferably additionally (as, for example, ternary or even multinear mixture), it is possible to admix an apolar component having a rather higher viscosity (still lower than the contrast component viscosity), for example having a viscosity in the range of 25-80 mPas it is, as already explained, thereby particularly preferably paraffinum perliquidum acts.

Thus, for example, a binary mixture of lipiodol ultrafluide, and tetradecane or hexadecane, or a binary mixture of lipiodol ultrafluide and paraffinum perliquidum, or a ternary mixture of lipiodol ultrafluide, tetradecane or hexadecane, and paraffinum perliquidum is particularly preferred.

According to the invention, the contrast agent is characterized in that the volume ratio of contrast component to further apolar component is in the range of 1: 1 to 1:10, preferably in the range of 1: 2-1: 8, particularly preferably in the range from 1: 4-1: 6.

This is in the Angio-injection method and the Angio-Perfusuinsmethode preferably the range for the volume ratio of a contrast component to another non-polar component, which is a rather higher viscosity (for example 25-80 mPas, see specifications above, corresponds to a Alkane, in particular an n-alkane or an isoalkane, having 20-30 carbon atoms such as paraffin oil, particularly preferably paraffinum perliquidum). Compare the volume ratio of contrast component (or contrast component already in a mixture with another apolar component, which has a rather higher viscosity) to another apo-laric component with a comparatively low viscosity (for example in the range of 1-10 mPas, cf. Specifications above, for example, corresponds to an alkane having 12-18, preferably 14-16 carbon atoms, or a mixture of such alkanes, more preferably an n-alkane or a mixture of such n-alkanes, eg, especially tetradecane or hexadecane) in the angio-injection method and the angio-perfusuins method, best considering the desired viscosity, for example, ratios (contrast component: apolar component having a comparatively low viscosity) in the range of 20: 1-100: 1 or preferably 30 : 1-70: 1 results.

For the so-called Angio-injection method, a ternary mixture is preferably used, wherein the contrast component (eg Lipiodol) and an apolar component with a rather higher viscosity (eg paraffinum perliquidum, in a sense as a carrier) in a ratio in the range of 1: 5 is used, and then the component with a relatively low viscosity (eg hexadecane and / or tetradecane), for example in a ratio of 50: 1 is used to adjust the viscosity of the entire mixture again depending on the X-ray contrast and the desired flow behavior.

In particular for Microangio thereby mixtures of contrast component and apolar component with a relatively low viscosity (eg, tetradecane or hexadecane) are used in a ratio of 1: 4 or 1: 6, wherein the amount of apolar component on the desired X-ray contrast and the penetration depth is set in small capillaries.

Furthermore, the present invention relates to a method for the angiographic examination of animal or human bodies or organs, components, e.g. of limbs, of it. The method is preferably characterized in that a contrast agent, as described above, is introduced into the blood vessel system and subsequently or synchronously recorded using X-rays, in particular a CT scan.

In addition, the present invention relates to a somewhat dynamic method for the angiographic examination of animal or human bodies or organs, components, e.g. of limbs of it. This method is characterized in that first a further apolar component as described above is introduced into the blood vessel system substantially continuously and circulated therein, and during a period of this apolar component a contrast component as characterized above is admixed, wherein subsequently synchronously or in sections recordings with the aid of X-rays, in particular a CT scan are made (so-called dynamic angiography, for example, first arterial imaging, then parenchymal imaging and then venous imaging, as a carrier paraffinum perliquidum, possibly in admixture with a decane [the term decane is to be understood in the sequence tetradecane and / or hexadecane], and a shock of contrast component is introduced). Incidentally, it is also generally possible to color the further component (s), e.g. is a red coloration of paraffinum perliquidum possible with sudan red.

Moreover, the present invention relates to the use of a contrast agent as described above for the angiographic examination of animal or human bodies or organs, components, e.g. of limbs of it.

Further preferred embodiments of the present invention are described in the dependent claims.

METHODS FOR CARRYING OUT THE INVENTION The proposed contrast agent can be used, for example, for microscopic vascular research (so-called microangio), but also for the angio-injection method or for the angio-perfusion method.

The preferred mixtures for these three methods are as follows:

microangio:

Lipiodol + decane (hexadecane or tetradecane), for example in the ratio 1: 4;

Angio-injection method:

Lipiodol + paraffin perliquidum + if necessary decane, for example in the ratio 1: 5 and decane until the desired viscosity is reached;

The angio-perfusion:

Perfusion with paraffinum perliquidum possibly supplemented with decane depending on the desired viscosity, in the existing and ongoing circulation bolus injection of lipiodol.

After we have successfully used oily perfusates and contrast agents on animal carcasses and human bodies as part of the development of minimally invasive postmortem angiography, an unexpectedly advantageous new mixture for the use of postmortem angiography using micro-CT was created on this basis. In contrast to our previously used oily liquids, microembolisms of the capillary system (S. Grabherr at al., A.IR 2006 in press) are not involved in this new mixture, but rather in the penetration and thus in the representation of this vessel area.

Ingredients: 1. Lipiodol® ultrafluide® (Guerbert, France) 2. Tetradecane (Tetradecan olefine free, Fluka, Switzerland) or Hexadecane (Hexadecane, Fluka, Switzerland) The composition of these components can be varied. The oily contrast agent Lipiodol ultrafluide® provides a high contrast (about 2000 HU), while decane serves as a diluent, which allows the Kapillargängigkeit. The more decane that is used, the lower the viscosity, and the smaller vessels can be represented.

As already successfully used mixtures, a ratio of lipiodol: decane of 1: 4 and 1: 6 is recommended.

Advantages of the novel contrast agent (i.v., for all three methods mentioned above): Practical Handling: One of the most essential advantages of this contrast agent mixture is the practical handling. It is sufficient a simple injection in the vessel area to be displayed.

Shelf life of the samples: Since the oily contrast agent remains intravascular, the samples can be stored for several days after the injection and only then examined.

Transportability of Samples: The long shelf life of the samples allows for transport between laboratories (e.g., injection in Bern, examination and analysis in the USA).

Repeated examination possibilities: Multiple scans and analyzes of a sample are possible, which is essential in unclear findings.

3D Ftekonstruktion with "zoom in" and virtual sample processing: With the help of the investigation by means of Micro-CT in addition to the two-dimensional and a three-dimensional reconstruction of the data possible. By "zooming in" and virtually cutting the samples, any areas can be enlarged, cut out and displayed without destroying the samples.

Quantification: Special software, e.g. for bone density measurement already exists for micro-CT applications, can be easily adapted to quantify the high-contrast vessels.

Selective, caliber-dependent representability: Depending on the mixing ratio, different vessel sections can be represented according to their caliber. Thus, only large supply vessels or capillary vessels can be made visible selectively.

Possibility of dynamic angiography: With appropriate injection technique, a precise discrimination of arterial, venous and capillary phase, in analogy to clinical angiography allowed.

Repeatability of Injection: When dynamic angiography is performed, flushing of the contrast agent from the vasculature is possible because of the lack of loss of the contrast agent into the surrounding tissue, allowing re-injection without falsification of the results by remnants of the previous injection. This is important when unclear findings occur in a phase of dynamic angiography.

Possibility of further investigations: The investigated organs can be embedded and additionally investigated morphologically (paraffin embedding and electron microscopic sectional examination). This is important if the 3D structure is to be correlated and compared with tissue morphology.

Experimental Section: Microangiography (Microangio):

In this method, a mixture of lipiodol and decane as a contrast agent (KM) was injected into the vascular system in a dead mouse and then a micro-CT was performed with a device of the type "Siemens Micro-CT scanner".

Preliminary test to test the contrast medium in the "live scanner": scan contrast medium (Lipiodol: decane = 1: 4) in 0.8 mm Venflon (indwelling cannula): KM is clearly visible.

[0045] 1. Mouse:

From below, KM (lipiodol: decane = 1: 4) into the vena cava inf .; Scan only upper body.

2. Mouse:

From below, KM (lipiodol: decane = 1: 6) into the vena cava inf .; no scan of the complete mouse; Organ removal for isolated organ scans: • Heart • Liver • Kidney • Head [0047] 3. Mouse:

From below, KM (lipiodol: decane = 1: 6) into the V cava inf .; Injection KM (lipiodol: decane = 1: 6) into right v. Saphena; 3 scans for full body imaging.

4. Mouse:

Injection KM (lipiodol: decane = 1: 6) in left ventricle; Scan only upper body.

5. Mouse:

Injection KM (lipiodol: decane = 1: 6) aorta (low) and v. Cava inf .; 2 scans (head and thorax).

6. Mouse:

Injection KM (lipiodol: decane = 1: 6) from below into the vena cava inf .; 2 scans (head and thorax).

7. Mouse:

Injection KM (lipiodol: decane = 1: 5) in V. porta; Organ removal for single scans: • Liver lobe (upper incl. Gallbladder) • Heart • Re u. [0052] In different reconstructions from the data set of the micro-CT scans given above, it can be seen that the contrast agent on the one hand permits high resolution and on the other hand permits excellent penetration even into very small vessel systems.

Angio-injection method:

Here, a manual injection of iodinated Contrast Lipiodol in 2 years formalin-fixed corpse preparations, the vessels were blocked with fixed blood.

Preparation with KM dilution series, where Lipiodol: paraffin oil (each as paraffinum perliquidum) 1: 1, 1: 5, 1:10 and 1:20 were examined. The following images were taken at 1: 5 because the best compromise between viscosity, contrast and penetration in vessels was found for the visualization.

Mixture of the contrast agent: Lipiodol: paraffin oil = 1: 5; per 500 ml of this mixture additionally about 10 ml of decane. After injection of the contrast agent mixture Multislice CT with reconstruction of the data as MIP and VRT.

In received images from the Angio-injection method on the one hand from the head, a kidney and a leg can be seen how the contrast agent used excellent contrast and despite the previously enclosed blood clots excellent penetration into the blood vessels allows without a noticeable Extravasation is recognizable.

Angio-perfusion method:

Angio trial on the human. Corpse, corpse: Anatomy corpse after Till fixation, already existing injuries (condition after knee operation left, open tibia fracture right).

Method: • Cannulation in the right groin (femoral artery, V. fomaralis). • Perfusion using the heart-lung machine (Perfusât: paraffin oil + decane, in the ratio of approx. 500 ml: 10 ml). Perfusion rate 5-10 ml per kg body weight / min. • Add the contrast agent Lipiodol (40 ml) to the perfusate (injection into the tube leading into the artery within a few seconds (bolus injection). • CT scans.

Result: successful perfusion (filling of the varices on the legs, filling of the carotid artery); Contrast in the CT.

The body examined suffered from death before PAOD (Peripheral Arterial Occlusive Disease), which led to a generally very poor circulation in the lower leg.

Contrast can be injected either as a bolus or given in larger quantities, with a bolus should be introduced within a short time span for dynamic angiography. Longer hoses of the heart-lung machine are advantageous for Ganzkörpercan to compensate for the movement of the CT table (typically about 3 m).

Summary:

The new contrast agent allows reliable, rapid, repeated examination and visualization of 2D and 3D vascular architecture in laboratory animals (e.g., Microangiography with Micro-CT) as well as post mortem on the human and animal body (Angio injection method). It also allows dynamic imaging and quantification of "blood loss" with

Claims (17)

the angio-perfusion method. Practical handling, possibilities of quantification as well as exact representation of different vessel sections will establish this method as a standard examination in the evaluation of genetically manipulated laboratory animals, pharmacological and toxicological studies as well as genetic engineering products. This new visualization and quantification method is intended to replace the old, reliable, but very time-consuming and highly specific techniques and pave the way for an expansive, simple, practical and straightforward application. claims A contrast agent for postmortem, experimental and / or diagnostic angiography and for the examination of animal or human bodies or components such as limbs or organs thereof, containing a substantially oil-based apolar contrast component for X-ray examinations, which contrast component has a contrast component viscosity in the range of 30-100 mPas, characterized in that the contrast component is present in a mixture with at least one further apolar component whose viscosity is lower or at most equal to the contrast component viscosity, and in that the volume ratio of contrast component to further apolar component in the range of 1: 1 until 1:10 lies. 2. A contrast agent according to claim 1, characterized in that the further apolar component is a substantially saturated, branched, unbranched or cyclic hydrocarbon, or a mixture of such hydrocarbons. 3. A contrast agent according to claim 2, characterized in that the further apolar component is an alkane or a mixture of alkanes, having a number of carbon atoms in the range of 5-45, particularly preferably in the range of 12-30. 4. A contrast agent according to claim 3, characterized in that it is the other apolar component is an alkane with 12-18, preferably 14-16 carbon atoms, or a mixture of such alkanes, which is particularly preferably a n-alkane or a mixture of such n-alkanes. 5. A contrast agent according to claim 3, characterized in that it is an alkane, in particular an n-alkane or an iso-alkane having 20-30 carbon atoms in the further apolar component, in particular paraffin oil, more preferably paraffinum perliquidum. 6. Contrast agent according to one of the preceding claims, characterized in that the contrast component has a viscosity in the range of 30-80 mPas. 7. The contrast agent according to claim 6, wherein the contrast component is an iodobased or sulfur-based X-ray contrast agent, particularly preferably an iodinated or brominated component or especially oil, for example a propyliodone, a fatty acid ethyl ester of iodinated poppy seed oil, or lodipine, more preferably lipidol ultrafluid. 8. Contrast agent according to one of the preceding claims, characterized in that the further apolar component has a viscosity which is lower than the contrast component viscosity. 9. A contrast agent according to claim 8, characterized in that the further apolar component has a viscosity in the range of 0.2-80 mPas, preferably in the range of 2-60 mPas. 10. A contrast agent according to any one of claims 8 or 9, characterized in that the further apolar component has a viscosity in the range of 1-10 mPas, preferably in the range of 2-4 mPas. 11. Contrast agent according to one of claims 8 or 9, characterized in that the further apolar component has a viscosity in the range of 25-80 mPas, which is particularly preferably paraffinum perliquidum. 12. Contrast agent according to one of the preceding claims, characterized in that the volume ratio of contrast component to further apolar component in the range of 1: 2-1: 8, preferably in the range of 1: 4-1: 6. 13. The contrast agent of claim 1, wherein the further apolar component is a mixture of a first further apolar component and a second further apolar component, wherein the first further component is an alkane with 12-18 , preferably having 14-16 carbon atoms, or is a mixture of such alkanes, more preferably an n-alkane or a mixture of such n-alkanes, and wherein the second further apolar component is an alkane, in particular a n-alkane or an isoalkane, having 20-30 carbon atoms, in particular paraffin oil, more preferably paraffinum perliquidum. 14. A contrast agent according to claim 1, characterized in that it is the other apolar component is a mixture of a first further apolar component and a second further apolar component, wherein the first further apolar component has a viscosity in the range of 1-10 mPas , preferably in the range of 2-4 mPas, and wherein the second further apolar component has a viscosity in the range of 25-80 mPas, wherein the second further apolar component is particularly preferably paraffinum per-liquidum. 15. A method for angiographic examination of animal or human bodies or organs, components such as limbs thereof, characterized in that a contrast agent according to one of the preceding claims is introduced into the blood vessel system and then or synchronously taking pictures with the aid of X-rays, in particular a CT scan , be made. 16. The method according to claim 15 for the angiographic examination of animal or human bodies or organs, components such as limbs thereof, characterized in that the method comprises the following steps: 1.) substantially continuous introduction of the further apolar component whose viscosity is lower or at most equal to the contrast component viscosity, in the blood vessel system, particularly preferably in the form of a mixture of paraffinum perliquidium and tetradecane and / or hexadecane; then 2.) circulating or passing the further apolar component; subsequently 3.) admixing of the contrast component, in particular preferably lipiodol, to the further apolar component, during a time period, and subsequently, 4.) synchronous or sectional recording with the aid of X-rays, in particular a CT scan. 17. Use of a contrast agent according to any one of claims 1 to 14 for angiographic examination of animal or human bodies or organs, components such as limbs thereof.