KR101735443B1 - Composition of contrast for selective coronary computed tomography angiography and method for injecting the same - Google Patents

Abstract

The present invention relates to a method for effectively injecting a contrast agent into a subject to obtain a high resolution CT image in selective catheter-directed coronary computed tomography angiography.
The present invention allows the use of iodine in the contrast medium at a very low concentration and allows observation of the vessel end of interest to high resolution.

Description

[0001] The present invention relates to a selective coronary artery CT imaging contrast agent,

The present invention relates to a contrast agent composition that can be used to obtain a high resolution CT image in selective catheter-directed coronary computed tomography angiography, and a method for effectively injecting the composition into a subject.

In general, invasive coronary angiography is performed by injecting a catheter into the cardiovascular region through the inferior vein and then injecting a contrast agent into the catheter. The coronary artery disease (CAD) And serves as an important criterion for treatment.

In order to obtain additional images, an intravascular ultrasound (IVUS) or optical coherence tomography (OCT) was additionally used to measure the luminal cross-sectional area, atherosclerotic plaque burden ) And plate characteristics.

This information plays a crucial role in successful vascular regeneration to minimize the risk of complications. However, such a method is limited in its use due to problems of procedural risks due to high cost and invasive properties.

Recently, intravenous coronary computed tomography angiography (IVCCTA) has been widely used to accurately diagnose luminal stenosis and atherosclerotic hemangiomas and vulnerabilities. The CCTA described above has similar results to IVUS in evaluating the minimum lumen area and area stenosis in patients with accurate chest pain, or calculating myocardial perfusion and CT-based fractionated blood reserve. These anatomical and physiological information can be useful in establishing procedural planning before undergoing coronary intervention.

Despite the advantages of IV CCTA as described above, the lack of accessibility to the device does not lead to much use of CCTA in the setting of coronary artery conduits. Recently, a system incorporating a coronary angiography system (INFX-8000C; Toshiba Medical Systems Corporation, Otawara, Japan) and a 320-detectpr row scanner (Aquilion One ViSION Edition) is used. When using the system described above, it is not necessary for the patient to move from the catheterization chamber to the CT imaging room when inserting the intra-coronary catheter, as well as to analyze information about the features of the atherosclerotic plaque around the lumen narrowing, The result is a non-invasive and invasive approach that facilitates coronary intervention. Therefore, it is necessary to develop a method of mixing and injecting a contrast agent in accordance with a new method of mixing an angiographic examination apparatus and a CT apparatus as described above.

(Non-Patent Document 01) Radiology. 256 (1), pp. 32-61 (2010.07.)

(Non-Patent Document 02) Practical Cardiology. 5 (4), pp. 28-31 (2009.)

In the present invention, the contrast injection protocol to be used in the mixing system of the angiographic examination equipment and the CT apparatus is defined. The contrast medium used in the contrast-guided coronary CT angiography, which can obtain high resolution while using the iodine concentration in the contrast medium, And a method for injecting the same.

According to an embodiment of the present invention, there is provided a contrast agent composition for selective coronary artery CT imaging, which comprises iodine (I) at a concentration of 10 to 18 mg / ml and is injected into a subject at a rate of 2 to 5 ml / to provide.

The angiographic contrast agent used in the present invention is not limited thereto, but is made of a radiopaque substance of iodine component. Angiographic agents may cause urticaria, dyspnea or hypotension, and may cause side effects such as skin and subcutaneous tissue damage due to extravasation, injection site pain, vascular injury, vasodilation, hypersensitivity, nephropathy or neurotoxicity Therefore, it is preferable to reduce the amount of the contrast agent used. By increasing the infusion rate, the amount of contrast agent can be reduced, but when the infusion rate is increased, the time available for contrast through the contrast agent is reduced.

However, in the present invention, in performing selective catheter-directed coronary computed tomography angiography (hereinafter, referred to as 'selective CCTA'), the injection amount of the contrast agent, the injection rate, and the concentration of iodine contained therein It has been found that a high resolution CT image can be obtained even when iodine is used in a very low content.

Specifically, according to a preferred embodiment of the present invention, the contrast agent composition is diluted with a solvent so as to contain iodine (I) in a concentration of 10 to 18 mg / ml, more preferably in a concentration of 13.13 to 17.19 mg / . Here, the type of the solvent is not particularly limited, but it is preferable to use, for example, saline.

Further, according to a more preferred embodiment of the present invention, the contrast agent composition may be injected into the test object at a rate of 2 to 5 ml / s, more preferably 2 ml / s to less than 3 ml / s. If the injection rate of the contrast agent is less than 2 ml / s, the CT image resolution may be lowered. If the injection rate is more than 5 ml / s, the contrast time may be reduced.

The contrast agent composition may be applied to the test specimen in an amount of 15 to 30 ml, more preferably 15 to 20 ml.

In a preferred embodiment of the present invention, iodine in the contrast agent composition may be injected into the test object at a rate of 20 to 90 mg / s, more preferably 26.26 mg / s to less than 51.57 mg / s. If the iodine infusion rate is less than 20 mg / s, the CT image resolution may be lowered. If the iodine injection rate is more than 90 mg / s, there is a possibility that the imaging time may be reduced.

In a more preferred embodiment of the present invention, the contrast agent composition comprises iodine (I) in a concentration of 13.13 to 17.19 mg / ml, wherein the amount of 15 to 20 ml is not less than 2 ml / s and less than 3 ml / Speed. ≪ / RTI >

According to another embodiment of the present invention, there is provided a method of preparing a mammal, the method comprising: (a) inserting a catheter into a blood vessel of a mammal other than a human; And

(b) injecting a contrast agent composition containing iodine (I) into the conduit at a rate of 2 to 5 ml / s.

In a preferred embodiment of the present invention, the contrast agent composition can be injected at a rate of 2 to 5 ml / s, more preferably at a rate of 2 ml / s to less than 3 ml / s. If the injection rate of the contrast agent is less than 2 ml / s, the resolution of the CT image may be lowered. If the injection rate exceeds 5 ml / s, the contrast time may be reduced.

Further, in a preferred embodiment of the present invention, the contrast agent composition may be injected into the conduit in an amount of 15 to 30 ml, more preferably in an amount of 15 to 20 ml.

In a preferred embodiment of the present invention, the contrast agent composition may be diluted with a solvent to include iodine (I) at a concentration of 10 to 18 mg / ml, more preferably at a concentration of 13.13 to 17.19 mg / ml. Here, the type of the solvent is not particularly limited, but it is preferable to use, for example, saline.

In a preferred embodiment of the present invention, iodine in the contrast agent composition may be injected at a rate of 20 to 90 mg / s, more preferably 26.26 mg / s to less than 51.51 mg / s. If the iodine injection rate is less than 20 mg / s, the CT image resolution may be lowered. If the iodine injection rate is more than 90 mg / s, there is a possibility that the imageable time is reduced.

According to a more preferred embodiment of the present invention, 15 to 20 ml of a contrast agent composition containing iodine (I) at a concentration of 13.13 to 17.19 mg / ml can be injected into the conduit at a rate of 2 ml / s to less than 3 ml / s .

In the present invention, although the injection rate of the contrast agent is slowed down and the amount of the contrast agent and the iodine content therein are significantly lowered, a clear CT image can be obtained by injecting the contrast agent for 5 to 10 seconds.

In the present invention, however, the position of injecting the contrast agent into the subject is not particularly limited, but injection of the contrast agent may be injected into the left coronary artery or the right coronary artery of the subject for CT imaging of the coronary artery.

In addition, in the present invention, the subject may be a mammal other than a human.

In the present invention, in the analysis and treatment of coronary artery disease (CAD), it is possible to perform on-site CT imaging after injecting a contrast agent into a pre-inserted conduit in a patient, Not only the inconvenience of moving the patient from the catheter insertion chamber to the CT imaging room is reduced but also the iodine content in the contrast agent used is significantly lowered so that the risk of side effects such as nephropathy is reduced and a high resolution three-

However, in the CT image of the present invention, the X-ray generator is disposed on one side of the subject and the X-ray detector is disposed on the opposite side so that the target portion of the crossed X-ray is uniformly passed in various directions systematically, The amount of X-rays is measured by the detector, and then the image is formed by a computer.

The cross section of the human body is composed of pixels (picture elements or pixels), and in order to obtain the pixels, a basic voxel of a rectangular parallelepiped having a width, a height and a height is required. In order to obtain an image of a cross section of the human body, a rectangular parallelepiped having a desired thickness or height and a horizontal and a vertical length is arranged, and the computer calculates the degree of X-ray absorption of each rectangular parallelepiped by calculation, , And then the number is described in various degrees of black and white according to the height and width of the CT window. The degree of X-ray absorption of each pixel in CT is called CT value or HU (Hounsfield Unit).

The present invention allows the use of iodine in the contrast medium at a very low concentration, and enables observation of the vessel's distal end of interest with high resolution.

FIG. 1 schematically shows the results of simultaneous selective CCTA scans according to injection of contrast agent in Experimental Example 1. FIG.
FIG. 2 is a representative TAG measurement image using a QAngio CT workstation in Experimental Example 1. FIG. The TAG value can be calculated automatically by measuring the lumen attenuation value using QAngio CT. The linear slope equation for the lumen strength information represents the TAG value of the scanned image in the selective CCTA according to the P1 protocol.
FIG. 3 shows the confidence interval of the lumen decay value in Experimental Example 1. FIG. The confidence interval represents an enhancement in the selective CCTA.
4 shows representative images of LAD and RCA arteries in selective CCTA according to protocol P1 in Experimental Example 1. FIG.
FIG. 5 shows the results of comparing TAGs according to the P1 and PIV protocols in LAD and RCA in Experimental Example 1. FIG.
6 shows the highest intensity projected image according to the protocols P6 and P _IV2 in LAD in Experimental Example 2. FIG.
7 is a graph comparing TAG according to the protocol of P6 and P _IV2 in LAD in Experimental Example 2. FIG.
FIG. 8 is a graph comparing TAG according to the protocol P1 to P _A1 to P _A17 in Experimental Example 3. FIG.

Hereinafter, the components and technical features of the present invention will be described in more detail with reference to the following examples. However, the following examples are intended to illustrate the contents of the present invention and are not intended to limit the scope of the invention.

Various embodiments described in the present invention are described with reference to the drawings. In the following description, for purposes of complete understanding of the present invention, various specific details are set forth, such as specific forms, compositions, and processes, and the like. However, certain embodiments may be practiced without one or more of these specific details, or with other known methods and forms. In other instances, well-known processes and techniques of manufacture are not described in any detail, in order not to unnecessarily obscure the present invention. Reference throughout this specification to "one embodiment" or "embodiment" means that a particular feature, form, composition, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. Accordingly, the appearances of the phrase " in one embodiment "or" the embodiment "in various places throughout this specification are not necessarily indicative of the same embodiment of the present invention. In addition, a particular feature, form, composition, or characteristic may be combined in any suitable manner in one or more embodiments.

[Experimental Example 1] Pig model experiment

Preparation for the experiment

The selective coronary CT angiography according to the present invention was performed on four female pigs of 35 to 40 kg. Four pigs were injected intramuscularly with a mixture of 5 mg / kg of enrofloxacin and 0.05 mg / kg of atropine, and 5 mg / kg of tyletramine (Zoletil 50; Virbac) A mixture of Rompun (Bayer) was injected. A 20-gauge catheter was then injected into the ear vein for intravenous injection. For muscle relaxation, 2% isoflurane (Forane) and 5 mg of beclomium bromide (0.10 mg / kg) were mixed and injected intravenously.

The right carotid artery of the pig was cut using a guide sheath to inject the catheter into the coronary artery, and a guide catheter (Cordis, JL 5-3.5) was inserted through the inserted sheath, Were inserted into the right coronary artery (RCA) or the left anterior descending artery (LAD).

5 ml of iodixanol contrast medium (Vispaque; GE Healthcare, Princeton, NJ) at a concentration of 320 mg / ml was injected by conventional coronary angiography to confirm proper catheterization. The heart rate was adjusted to 70-80 beats / min in the initial 100-120 beats / min by injecting IV bolus of Esmorol 40mg.

CT protocol

A 320-multi-detector CT scanner (Aquilion ONE; Toshiba Medical Systems Corporation, Otawara, Japan) was used for CT scans and the oxygen respirator temporarily stopped its operation for respiratory arrest during CT scanning. CT scans were performed using retrospective electrocardiogram gating, collimation and slice thickness, 0.5 mm; Reconstruction increment, 0.3 mm; Tube rotation time, 0.35 seconds; Tube voltage, 120 kV (p); Current, 550mA; And reconstruction field of a view, from 109 to 123 mm, from the skull to the tail. In all experiments the data were restored to 75% of the R-R length. If there is motion noise, another heart step was chosen. The following modulations were used for reconstruction: kernel, FC43; A reconstruction algorithm, AIDR 3D (Adaptive Iterative Dose Reduction 3D).

Selective CCTA experiments

Contrast medium (Iomeron 400 mg / ml; Bracco, Milan, Italy) was diluted in physiological saline for optimal coronary angiographic enhancement. The concentration of iodine in the contrast medium was adjusted to 13.13 mg / ml to obtain a 350HU value under a CT voltage of 120 kV (p). The diluted contrast agent was injected into the pig model using a dual-head power injector (Medrad Stellant Injector, Medrad Indianola, PA) according to the following protocol. Protocol 1 (P1), injection rate, contrast medium volume, 2 ml / s, 20 ml; Protocol 2 (P2), 3 ml / s, 20 ml; Protocol 3 (P3), 3 ml / s, 30 ml; Protocol 4 (P4), 4 ml / s, 20 ml; And Protocol 5 (P5), 4ml / s, 30ml. These protocol parameters are summarized in Table 1 below. An optional CCTA scan was performed simultaneously with the injection of the contrast agent. Retrospective ECG gating was performed without volume control, and the scanning period was fixed at 10 seconds so that the injection rate and volume were negligible in each protocol. Therefore, the actual injection time for each protocol was different (Fig. 1). Continuous volumes (6-7 sets on average per volume) were obtained during a 10 second scan. The contrast was removed from the coronary arteries at intervals of 5 minutes for each injection, and the condition of the experimental animals was kept medically stable. Since the above protocol can be performed by separating the right coronary artery or the left coronary artery, a CT image can be obtained selectively for each of the left and right coronary arteries.

protocol Voltage (kVp) Current (mA) Contrast agent concentration (mg / ml) Volume (ml) Infusion rate (ml / s) Iodine flow (ml / s) P1 120 550 13.13 20 2 26.26 P2 120 550 13.13 20 3 39.39 P3 120 550 13.13 30 3 39.39 P4 120 550 13.13 20 4 52.52 P5 120 550 13.13 30 4 52.52

IV CCTA experiment

For the IV CCTA experiment, the contrast agent was directly injected into the vein of the pig by the following protocol and CT was performed. For the specific protocol (P _IV ), 60 ml of contrast medium (Iomeron 400 from Bracco) containing iodine at a concentration of 400 mg / ml was injected at a rate of 5 ml / s through a dual head power injector and 30 ml of saline was injected at the same rate Respectively. The timing-bolus technique was used to monitor contrast values in the ascending aorta. Sequential monitoring for bolus tracking began with a low dose of contrast medium (120 kV, 20 mAAs). CT scans were automatically initiated using retrospective ECG synchronization when the imaging value reached 180 HU in the ascending aorta.

Image analysis

After transferring the obtained selective CCTA images to a workstation (Vitrea fx6 4; Vital Images), a level 3 level CT reader which does not know the optional CCTA protocol is used as a representative image for each protocol, for example, (3-D) images were used to enhance the distal portion of the artery and select the best-in-focus image to maximize the projected image intensity.

Selected representative images were transferred to another standalone workstation (QAngio CT workstation, Version 2.0.2; Medis Medical Imaging Systems, Leiden, the Nerhterlands) using USB to describe the lumen boundary and analyze the strength of the lumen. The anatomy definition of the Society of Cardiovascular Computed Tomography (SCCT) was used to measure both the middle and distant sites near RCA and LAD. Section strength was automatically recorded at 0.5 mm intervals. A transluminal attenuation gradient (TAG), known as a linear regression coefficient between the lumen CT value and the measured centerline length of the coronary artery, was used. A representative example of the TAG measurement is shown in Fig.

Statistical method

A mixed model involving least squared means using Bonferroni correction was used to evaluate the statistical significance of the attenuation values between the two experiments. The attenuation values were expressed as mean and standard error (SE), and 95% confidence intervals were used to report associations consistent with the appropriate enhancement range of 250 to 350 HU. The differences in the least mean squares were used to compare the differences of the mean values according to the protocol in each part. All statistical analyzes were performed using SAS statistical software (SAS System for Windows; Version 9.2, SAS Institute, Cary, NC).

Experiment result

The mean decay values (HU) for the selective CCTA (P1, P2, P3, P4 and P5) and IV CCTA (P _IV ) are shown in Table 2 below, and the confidence intervals of the coronary CT 3.

P1 P2 P3 P4 P5 P _IV blood vessel
(HU) LAD 270.3 ± 20.4 262.9 ± 20.4 276.8 ± 20.4 268.0 ± 20.4 251.3 + - 20.4 389.9 ± 20.5 RCA 322.6 ± 7.4 264.7 ± 7.4 274.0 + - 7.4 277.7 ± 7.4 334.7 ± 7.4 354.4 ± 7.7 part
(HU) pLAD 284.2 ± 23.1 294.7 ± 23.1 300.4 ± 23.1 287.2 ± 23.1 294.6 ± 23.1 425.9 ± 23.2 mLAD 297.6 ± 19.9 277.5 ± 19.9 277.4 ± 19.9 284.7 ± 19.9 250.2 ± 19.9 413.4 ± 18.5 dLAD 230.0 ± 18.4 216.4 ± 18.4 240.5 ± 18.5 232.8 ± 18.4 205.1 ± 18.4 335.6 ± 18.5 pRCA 341.6 + - 8.0 282.7 ± 8.0 294.2 ± 8.0 289.1 + - 8.0 351.0 + - 8.0 357.4 ± 8.8 mRCA 319.3 ± 7.4 275.1 + - 7.4 265.6 ± 7.5 291.2 + - 7.4 352.5 ± 7.4 361.8 ± 8.0 dRCA 302.4 ± 16.7 230.8 ± 16.7 253.3 + - 16.8 254.4 + 16.7 296.8 ± 16.7 349.2 + - 16.8 Heart rate
(beat / min) 64 ± 2 66 ± 3 65 ± 4 66 ± 4 65 ± 1 64 ± 3

As shown in Table 2 and FIG. 3, in the blood vessel analysis, it can be seen that the average decay value of the selective CCTA protocol according to the present invention generally falls within the range of 250 to 350 HU, which is known as the optimal contrast enhancement range. The mean decay value of the selective CCTA test at each site was found to be within the appropriate range of enhancement suggested in the proximal and middle coronary arteries. Generally, the mean decay value was higher in the right coronary artery than in the left coronary artery I could see that it was measured.

As described above, the selective CCTA protocol according to the present invention is very suitable for medical applications when the average decay value of each CCTA belongs to the optimal range. In particular, P1 indicates that the 95% confidence interval of the decay range is the optimal contrast enhancement range (mid-LAD, mid-RCA, distal RCA). The representative image of P1 is further shown in Fig. FIG. 4A shows a 3D image of LAD, B is the highest intensity projected image of LAD, C is a reconstructed image of a curved multi-plane of LAD, D is a three-dimensional image of RCA, Intensity projection image, and F is a reconstructed image of a bending multi-plane of RCA.

On the other hand, IV CCTA was performed with 1.5 ml / kg of contrast medium, and it was observed that the attenuation value exceeded 350 HU, and the 95% confidence interval deviates from the optimal enhancement range in all protocols (Fig. 3).

To confirm the homogeneity of the attenuation values, the TAG values of P1 and P _IV were compared to zero, which implies high homogeneity. Figure 5 illustrates by comparing the representative case of TAG of P1 and P _IV from the left coronary artery and the right coronary artery, A will showing a close-up photo of the LAD in the P _IV IV experiments, B is LAD in the selective CCTA P1 , And C is a comparison of the landscape attenuation slope for LAD in P _IV and P 1 (-1.5245, -1.7558, respectively). D is an enlarged picture of RCA in P _IV of IV experiment, E is an enlarged picture of RCA in P1 of selective CCTA, F is a comparison of RCA with RCA in P _IV and P 1 (0.0459, 0.0799, respectively). As shown in this FIG 5, the TAG P1 has been confirmed that more uniform than in the _{P IV (LAD: -1.5245 vs -1.7558} , p <0.001; RCA: 0.0459 vs 0.0799, p <0.001).

In general, when iodine-containing contrast agents are used, nephropathy is induced in a concentration-dependent manner. Therefore, the use of contrast media should be minimized to prevent contrast-induced nephropathy.

In the present invention, by limiting the injection rate and amount of the contrast agent injected into the selective CCTA to a specific range, it is possible to obtain an excellent contrast value even if the content of iodine contained in the contrast agent is significantly lowered. More specifically, the P1 protocol uses 263 mg of iodine, which is only 1.09% of the amount of iodine used in P _IV , but an excellent contrast value of 250 to 350 HU is obtained, which is comparable to IV CCTA It can be seen that it has a stable contrast enhancement efficiency.

[Experimental Example 2] Clinical patient experiment

Selective CCTA experiments

A 71-year-old female patient (height: 155.0 cm, weight: 66 kg) was inserted through the inferior vein into the coronary artery and then injected with the following protocol (P6) through the catheter using a double head power injector . Concentration of iodine in the contrast medium: 17.19 mg / ml, Contrast agent total volume 15 ml, Contrast agent injection rate 5 ml / s, Iodine injection rate 85.95 mg / s; The selective CCTA scan was performed simultaneously with the injection of the contrast agent, and the CT voltage was set to 100 kVp to reduce the radiation dose to the patient. Retrospective ECG gating was performed without volume control, and the scanning period was fixed at 10 seconds so that the injection rate and volume were negligible in each protocol. At the time of scanning, the above protocol could be performed by separating the right coronary artery or the left coronary artery, so that a CT image could be selectively obtained for each of the left and right coronary arteries.

IV CCTA experiment

CT was performed after direct injection of contrast agent into the patient's vein using the following protocol. For the specific protocol (P _IV2 ), 60 ml of contrast medium (Iomeron 400 from Bracco) containing iodine at a concentration of 400 mg / ml was injected at a rate of 5 ml / s through a dual head power injector and 30 ml of saline was injected at the same rate Respectively. Timing-bolus techniques were used to monitor contrast values in the ascending aorta. Sequential monitoring for bolus tracking began with a low dose of contrast medium (120 kV, 20 mAAs). CT scans were automatically initiated using retrospective ECG synchronization when the imaging value reached 180 HU in the ascending aorta.

Statistical method

A mixed model involving least squared means using Bonferroni correction was used to evaluate the statistical significance of the attenuation values between the two experiments. The attenuation values were expressed as mean and standard error (SE), and 95% confidence intervals were used to report associations consistent with the appropriate enhancement range of 250 to 350 HU. The differences in the least mean squares were used to compare the differences of the mean values according to the protocol in each part. All statistical analyzes were performed using SAS statistical software (SAS System for Windows; Version 9.2, SAS Institute, Cary, NC).

Experiment result

The average attenuation values and SE values in the selective CCTA (P6) and IV CCTA (P _IV2 ) are shown in Table 3 below, and the highest intensity projected images in P6 and P _IV2 are shown in FIG. 6, Are shown in FIG. 7 as a graph.

Q1 (HU) Median (HU) Q3 (HU) Mean (HU) SD (HU) Angiography Optional CCTA 258.74 277.26 277.26 285.78 37.48 IV CCTA 195.33 240.40 284.14 245.44 55.79

As shown in Table 3 and FIG. 6, the attenuation value of the selective CCTA protocol (P6) according to the present invention falls within the range of 250 to 350 HU, which is known as the optimal enhancement range. (A) shows the coronary artery photograph according to the P6 protocol, and (b) shows the coronary artery photograph according to the P _IV2 protocol.

Further, as shown in FIG. 7, when the selective CCTA protocol (P6) according to the present invention did not cause a decrease in the intravascular brightness value, the IV CCTA (P _IV2 ) As the distance increases, the brightness decreases.

In the above Experimental Example 2, the amount of iodine contained in the contrast agent was increased to 17.19 mg / ml in consideration of the amount of radiation absorbed in cells, fat and surrounding organs of the human body. However, The use of iodine in very small amounts can be seen compared to the IV CCTA used.

[Experimental Example 3] Protocol experiment

A contrast agent (iodine concentration: 400 mg / ml, Iomeron 400 from Bracco) was diluted in a solvent and injected into a conduit fixed to the pig model prepared in Experimental Example 1 at the same time as the protocol described in Table 4, and a selective CCTA scan was performed. The TAGs according to the respective protocols are compared and shown graphically in FIG.

protocol Voltage (kVp) Current (mA) Contrast agent: solvent volume ratio Contrast agent concentration (mg / ml) Volume (ml) Injection rate
(ml / s) Iodine flow (ml / s) P _A1 120 300 1:15 25 40 4 100 P _A2 120 450 1:15 25 40 4 100 P _A3 100 550 1:15 25 40 4 100 P _A4 120 300 1:15 25 50 5 125 P _A5 100 550 1:15 25 50 5 125 P _A6 120 300 1:15 25 60 6 150 P _A7 120 450 1:15 25 60 6 150 P _A8 100 550 1:15 25 60 6 150 P _A9 120 300 1:16 23.53 40 4 94 P _A10 120 450 1:16 23.53 40 4 94 P _A11 100 550 1:16 23.53 40 4 94 P _A12 120 300 1:16 23.53 50 5 117 P _A13 120 450 1:16 23.53 50 5 117 P _A14 100 550 1:16 23.53 50 5 117 P _A15 120 300 1:16 23.53 60 6 141 P _A16 120 450 1:16 23.53 60 6 141 P _A17 100 550 1:16 23.53 60 6 141 P1 120 550 1: 30.46 13.13 20 2 26.26

Statistical method

A mixed model involving least squared means using Bonferroni correction was used to evaluate the statistical significance of the attenuation values between the two experiments. The attenuation values were expressed as mean and standard error (SE), and 95% confidence intervals were used to report associations consistent with the appropriate enhancement range of 250 to 350 HU. The differences in the least mean squares were used to compare the differences of the mean values according to the protocol in each part. All statistical analyzes were performed using SAS statistical software (SAS System for Windows; Version 9.2, SAS Institute, Cary, NC).

Experiment result

As shown in FIG. 8, the brightness values exceeding the optimal enhancement range (250 to 350 HU) are shown when the content of iodine in the contrast medium is increased, the amount of contrast agent used and the injection rate are increased (P _A1 to P _A17 ) , It can be seen that a stable attenuation value is exhibited within the optimum enhancement range.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, It will be obvious to those of ordinary skill in the art.

Claims (12)

delete delete delete delete delete delete (a) inserting a catheter into a left or right coronary artery of a mammalian subject other than a human; And
(b) an amount of 15 to 20 ml of a contrast agent composition containing iodine (I) at a concentration of 13.13 to 17.19 mg / ml is injected through the conduit at a rate of 2 to 5 ml / s into the left coronary artery or right coronary artery And injecting the selected conduit-induced coronary CT contrast agent directly into the artery. delete 8. The method of claim 7,
Wherein the contrast agent composition comprises a solvent. 10. The method of claim 9,
Wherein the solvent is saline. 8. The method of claim 7,
Wherein the iodine in the contrast agent composition is injected at a rate of 26.26 to 85.95 mg / s. delete

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