In vitro comparative flow phantom study about the difference of relaxivity between Gadomer-17 and Gd-DTPA using high resoultion 3D-TOF MRA

Abstract

[한글]

In Vitro comparative flow phantom study about the difference of relaxivity between

Gadomer-17 and Gd-DTPA using high resolution 3D-TOF MRA

Byung-June Jo

Department of Medicine, The Graduate School, Yonsei University

(Directed by Associate Professor Tae-Sub Chung)

With the recent development of magnetic resonance imaging, the visualization of

small vasculatures has become possible. Especially, high resolution 3D-TOF MRA

technique has enabled us to obtain higher resolution images and visualization of

tortuous vessel structures running parallel into the slice, such as the cerebral

vessel, compared with two-dimensional MRA because of its lower saturation effect.

Also, to reduce the saturation effect of TOF MRA, MR contrast agents are being

used. Gadomer-17, a new macromolecular blood pool agent, is known to have three to

four times higher relaxivity than that Gd-DTPA.

The purpose of our study was to reveal the difference of relaxivity between

Gadomer-17 and Gd-DTPA applying high resolution 3D-TOF MRA with slice interpolation

technique using a flow phantom model and to support the preliminary data about the

proper dose concentration of Gadomer-17.

In the pulsating flow system, three concentrations of Gadomer-17 and Gd-DTPA were

filled. Using the carotid phantom model composed of normal and 70% stenosis, MRA

was obtained by 3D-TOF MRA with slice interpolation technique. By the visual

analysis of vessel conspicuity, the degree of compensation effects of contrast

agents over the turbulent flow-related artifact was done in MIP reconstructed

images. For quantitative analysis, the signal intensities were measured in the

axial base 3D-TOF images, and relative contrast enhancement was calculated. The

results of our studies were;

1. Maximal signal intensities were obtained at 1mmol/L of Gadomer-17 and at

1mmol/L of Gadomer-17 and 4mmol/L Gd-DTPA.

2. In the flow phantom model study, maximal signal intensities were obtained at

1mmol/L of Gadomer-17 and at 1mmol/L of Gadomer-17 and 4mmol/L Gd-DTPA.

3. Flow-related signal loss was compensated by Gd-DTPA proportional to

concentration, but Gadomer-17 did not show such a dose accumulative effect.

Conclusively, the left-sided shifting of signal intensities-to-concentration of

contrast curve suggest the intrinsic higher relativity of Gadomer-17 over Gd-DTPA.

Improvement of MRA image quality and higher signal intensities of the vessel were

obtained in the lower concentration of Gadomer-17 than that of Gd-DTPA.

With the recent development of magnetic resonance imaging, the visualization of

small vasculatures has become possible. Especially, high resolution 3D-TOF MRA

technique has enabled us to obtain higher resolution images and visualization of

tortuous vessel structures running parallel into the slice, such as the cerebral

vessel, compared with two-dimensional MRA because of its lower saturation effect.

Also, to reduce the saturation effect of TOF MRA, MR contrast agents are being

used. Gadomer-17, a new macromolecular blood pool agent, is known to have three to

four times higher relaxivity than that Gd-DTPA.

The purpose of our study was to reveal the difference of relaxivity between

Gadomer-17 and Gd-DTPA applying high resolution 3D-TOF MRA with slice interpolation

technique using a flow phantom model and to support the preliminary data about the

proper dose concentration of Gadomer-17.

In the pulsating flow system, three concentrations of Gadomer-17 and Gd-DTPA were

filled. Using the carotid phantom model composed of normal and 70% stenosis, MRA

was obtained by 3D-TOF MRA with slice interpolation technique. By the visual

analysis of vessel conspicuity, the degree of compensation effects of contrast

agents over the turbulent flow-related artifact was done in MIP reconstructed

images. For quantitative analysis, the signal intensities were measured in the

axial base 3D-TOF images, and relative contrast enhancement was calculated. The

results of our studies were;

1. Maximal signal intensities were obtained at 1mmol/L of Gadomer-17 and at

1mmol/L of Gadomer-17 and 4mmol/L Gd-DTPA.

2. In the flow phantom model study, maximal signal intensities were obtained at

1mmol/L of Gadomer-17 and at 1mmol/L of Gadomer-17 and 4mmol/L Gd-DTPA.

3. Flow-related signal loss was compensated by Gd-DTPA proportional to

concentration, but Gadomer-17 did not show such a dose accumulative effect.

Conclusively, the left-sided shifting of signal intensities-to-concentration of

contrast curve suggest the intrinsic higher relativity of Gadomer-17 over Gd-DTPA.

Improvement of MRA image quality and higher signal intensities of the vessel were

obtained in the lower concentration of Gadomer-17 than that of Gd-DTPA.

최근에 자기공명혈관조영술의 발달로 미세한 혈관조직의 영상화가 가능해졌다. 특히 최근 개발된 고해상 절편중첩기법 삼차원-TOf 자기공명혈관조영술은 기존의 이차원-TOF 자기공명혈관조영술에 비해 고해상도의 혈관영상을 만들 수 있고 절편 내에서 절편과 평행하게 달리는 혈관에 대한 포화효과(saturation effect)가 적어 구불구불한 뇌혈관의 영상화에 유리하다. 또한 TOF 자기공명혈관조영술의 단점인 포화효과를 줄이기 위해 조영제를 사용하고 있다. 최근에 개발된 Gadomer-17은 기존에 널리 사용되는 Gd-DTPA에 비해 4배 정도 높은 이완도 (relativity)를 보인다고 보고되었지만 이러한 데이터는 Gadomer-17의 개발자인 Weinmann이 토끼를 이용한 동물생체실험과 가상컴퓨터 모델로써 계산한 수치만이 알려져 있을 뿐이다. 따라서 Gadomer-17의 Gd-DTPA에 비해 상대적으로 높은 이완도가 생체내의 여러 변수요인에 의한 것인지 아니면 그 물질자체의 특성에 의한 것인지는 아직 알려져 있지 않다. 본 연구는 이러한 제한된 정보만이 알려진 Gadomer-17을 이용하여 고해상 절편중첩 기법 삼차원-TOF 자기공명혈관조영술을 촬영함으로써 Gadomer-17의 Gd-DTPA에 비해 상대적으로 높은 이완도를 영상적으로 구현하고자 하며 나아가 조영효과의 극대화를 위한 적정 조영제 농도 결정에 관한 기본적인 데이타를 제시하는 데 그 목적이 있다.

본 연구에서는 우선 Gd-DTPA와 Gadomer-17 일련의 농도용액을 가지고 최적의 농도를 구한 후 자기공명혈관조영술을 시행하여 각각의 용액에서 신호강도를 측정하여 최고 신호강도를 보이는 농도를 얻었다. 정상과 협착이 있는 경동맥 혈류모델을 이용하여 용액 농도에 따른 신호강도곡선을 얻어 Gd-DTPA와 Gadomer-17간의 차이가 있는 지를 알아보고 조영 전, 후의 신호강도를 구하여 자기공명혈관조영술의 percent enhancement 정도와 경동맥 혈류모델의 영상의 질적 우수와 최적의 신호강도를 보이는 농도를 구하였으며 다음과 같은 결과를 얻었다.

1. Gadomer-17은 1mmol/L, Gd-DTPA는 4mmol/L농도와 용액에서 가장 높은 신호강도가 나타났다.

2. 경동맥 혈류모델에서도 Gadomer-17과 Gd-DTPA는 각각 1mmol/L, 4mmol/L에서 가장 강한 신호강도를 나타내었다.

3. 70% 협착 경동맥 혈류모델을 이용한 실험에서도 와류로 인한 협착부 이하의 신호강도 감소가 Gadomer-17은 1mmol/L, Gd-DTPA에서는 4mmol/L에서 가장 적게 나타났다.

이상의 결과에서 Gadomer-17의 Gd-DTPA에 비해 상대적으로 높은 이완도의차이가 농도-신호강도곡선의 좌측이동의 소견으로 나타났고 Gadomer-17은 Gd-DTPA에 비해 적은 농도에서 강한 신호강도와 전체적인 혈관조영술의 영상의 질이 높았다.

[영문]

With the recent development of magnetic resonance imaging, the visualization of small vasculatures has become possible. Especially, high resolution 3D-TOF MRA technique has enabled us to obtain higher resolution images and visualization of tortuous vessel structures running parallel into the slice, such as the cerebral vessel, compared with two-dimensional MRA because of its lower saturation effect. Also, to reduce the saturation effect of TOF MRA, MR contrast agents are being used. Gadomer-17, a new macromolecular blood pool agent, is known to have three to

four times higher relaxivity than that Gd-DTPA.

The purpose of our study was to reveal the difference of relaxivity between Gadomer-17 and Gd-DTPA applying high resolution 3D-TOF MRA with slice interpolation technique using a flow phantom model and to support the preliminary data about the

proper dose concentration of Gadomer-17.

In the pulsating flow system, three concentrations of Gadomer-17 and Gd-DTPA were filled. Using the carotid phantom model composed of normal and 70% stenosis, MRA was obtained by 3D-TOF MRA with slice interpolation technique. By the visual analysis of vessel conspicuity, the degree of compensation effects of contrast agents over the turbulent flow-related artifact was done in MIP reconstructed images. For quantitative analysis, the signal intensities were measured in the axial base 3D-TOF images, and relative contrast enhancement was calculated. The results of our studies were;

1. Maximal signal intensities were obtained at 1mmol/L of Gadomer-17 and at 1mmol/L of Gadomer-17 and 4mmol/L Gd-DTPA.

2. In the flow phantom model study, maximal signal intensities were obtained at 1mmol/L of Gadomer-17 and at 1mmol/L of Gadomer-17 and 4mmol/L Gd-DTPA.

3. Flow-related signal loss was compensated by Gd-DTPA proportional to concentration, but Gadomer-17 did not show such a dose accumulative effect.

Conclusively, the left-sided shifting of signal intensities-to-concentration of contrast curve suggest the intrinsic higher relativity of Gadomer-17 over Gd-DTPA. Improvement of MRA image quality and higher signal intensities of the vessel were obtained in the lower concentration of Gadomer-17 than that of Gd-DTPA.

With the recent development of magnetic resonance imaging, the visualization of small vasculatures has become possible. Especially, high resolution 3D-TOF MRA technique has enabled us to obtain higher resolution images and visualization of tortuous vessel structures running parallel into the slice, such as the cerebral vessel, compared with two-dimensional MRA because of its lower saturation effect. Also, to reduce the saturation effect of TOF MRA, MR contrast agents are being used. Gadomer-17, a new macromolecular blood pool agent, is known to have three to four times higher relaxivity than that Gd-DTPA.

The purpose of our study was to reveal the difference of relaxivity between Gadomer-17 and Gd-DTPA applying high resolution 3D-TOF MRA with slice interpolation technique using a flow phantom model and to support the preliminary data about the

proper dose concentration of Gadomer-17.

In the pulsating flow system, three concentrations of Gadomer-17 and Gd-DTPA were filled. Using the carotid phantom model composed of normal and 70% stenosis, MRA was obtained by 3D-TOF MRA with slice interpolation technique. By the visual analysis of vessel conspicuity, the degree of compensation effects of contrast agents over the turbulent flow-related artifact was done in MIP reconstructed images. For quantitative analysis, the signal intensities were measured in the axial base 3D-TOF images, and relative contrast enhancement was calculated. The results of our studies were;

1. Maximal signal intensities were obtained at 1mmol/L of Gadomer-17 and at 1mmol/L of Gadomer-17 and 4mmol/L Gd-DTPA.

2. In the flow phantom model study, maximal signal intensities were obtained at 1mmol/L of Gadomer-17 and at 1mmol/L of Gadomer-17 and 4mmol/L Gd-DTPA.

3. Flow-related signal loss was compensated by Gd-DTPA proportional to concentration, but Gadomer-17 did not show such a dose accumulative effect.

Conclusively, the left-sided shifting of signal intensities-to-concentration of contrast curve suggest the intrinsic higher relativity of Gadomer-17 over Gd-DTPA.

Improvement of MRA image quality and higher signal intensities of the vessel were obtained in the lower concentration of Gadomer-17 than that of Gd-DTPA.