A Study of Feasibility of Brain Imaging in Medium- and Small-Sized Animals: Using a Clinical 3T MR System with Three Surface Coils

Shin Young Park; Mi Ri Jeong; Byung Mann Cho; Kang Soo Kim; Hak Jin Kim

doi:10.3348/jksr.2017.77.5.317

Journal List > J Korean Soc Radiol > v.77(5) > 1087863

Go to TopGo to Top Go to BottomGo to Bottom

TOOLS

Park, Jeong, Cho, Kim, and Kim: A Study of Feasibility of Brain Imaging in Medium- and Small-Sized Animals: Using a Clinical 3T MR System with Three Surface Coils

Original Article

J Korean Soc Radiol 2017;77(5):317-326.

Published online: 19 January 2017

DOI: https://doi.org/10.3348/jksr.2017.77.5.317

A Study of Feasibility of Brain Imaging in Medium- and Small-Sized Animals: Using a Clinical 3T MR System with Three Surface Coils

Shin Young Park, MD¹, Mi Ri Jeong, MD¹, Byung Mann Cho, MD², Kang Soo Kim, MS³, Hak Jin Kim, MD^*,¹

¹Department of Radiology, Pusan National University Hospital, Pusan National University College of Medicine, Busan, Korea

²Department of Preventive Medicine, Pusan National University College of Medicine, Busan, Korea

³MR Application Specialist, Siemens Healthcare Korea, Seoul, Korea

^*Corresponding author: Hak Jin Kim, MD Department of Radiology, Pusan National University Hospital, Pusan National University College of Medicine, 179 Gudeok-ro, Seo-gu, Busan 49241, Korea. Tel. 82-51-240-7371 Fax. 82-51-244-7534 E-mail: hakjink@pusan.ac.kr

Received 20 January 201713 March 2017 Accepted 21 May 2017

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Purpose

To evaluate which brain MR images obtained with a clinical 3T MR system using surface coils less than 15.4 cm in diameter are best in rabbit and rat models, and to assess the feasibility of the clinical 3T MR machine in the study of morphologic brain in a preclinical study using medium- and small-sized animal models.

Materials and Methods

Brain T2-weighted image (T2WI), T1-weighted image (T1WI), diffusion-weighted image (DWI), and susceptibility-weighted image (SWI) were obtained, and MR angiography was performed with a clinical 3T MR system using a rat, a cat, and a knee coil (5, 12, and 15.4 cm in diameter, respectively) in normal rabbits (n = 3) and using a rat and a cat coil in normal rats (n = 3). MR images were assessed qualitatively by consensus of two neuroradiologists and quantitatively using signal-to-noise ratio (SNR) and statistical analysis (using analysis of variance or t-test) in terms of which images obtained with different coils were the best. Brain T2WI, DWI, SWI, and Gd-T1WI MR images were obtained 2 hours after embolization with triolein emulsion infused into the carotid artery in rabbits (n = 3) and rats (n = 3) using the coil which showed highest SNR in the above study, and the images were assessed in terms of abnormal findings and image quality.

Results

Brain MR images obtained with the rat coil revealed better image quality and higher SNR compared with those obtained with other coils, and they showed statisti-cal significance (p < 0.05) in rabbits. In rats, brain MR images obtained with the rat coil were better than those obtained with the cat coil in qualitative analysis; however, they revealed no statistical significance except for DWI in quantitative analysis. MR images obtained after triolein emulsion showed T2 hyperintensity and lesional contrast enhancement on Gd-T1WI without evidence of infarction or hemorrhage.

Conclusion

The clinical 3T MR system using surface coils for animals enabled us to obtain good quality brain images in medium- and small-sized animal models in the present study. Brain MR images seem to be feasible for the morphologic evaluation in animal models.

Go to :

Keywords: MRI Animal Research Fat Embolism

REFERENCES

1.Liang CC., Liu HL., Chang SD., Chen SH., Lee TH. The protective effect of human umbilical cord blood CD34+ cells and es-tradiol against focal cerebral ischemia in female ovariecto-mized rat: cerebral MR imaging and immunohistochemical study. PLoS One. 2016. 11:e0147133.

2.Bearer EL., Zhang X., Janvelyan D., Boulat B., Jacobs RE. Reward circuitry is perturbed in the absence of the serotonin trans-porter. Neuroimage. 2009. 46:1091–1104.

3.Kim HJ., Lee CH., Kim HG., Lee SD., Son SM., Kim YW, et al. Re-versible MR changes in the cat brain after cerebral fat em-bolism induced by triolein emulsion. AJNR Am J Neuroradiol. 2004. 25:958–963.

4.Kim HJ., Lee CH., Lee SH., Cho BM., Kim HK., Park BR, et al. Early development of vasogenic edema in experimental cerebral fat embolism in cats: correlation with MRI and electron microscopic findings. Invest Radiol. 2001. 36:460–469.

5.Kim HJ., Lee CH., Lee SH., Moon TY. Magnetic resonance im-aging and histologic findings of experimental cerebral fat embolism. Invest Radiol. 2003. 38:625–634.

6.Kim HJ., Lee JH., Lee CH., Lee SH., Moon TY., Cho BM, et al. Ex-perimental cerebral fat embolism: embolic effects of triole-in and oleic acid depicted by MR imaging and electron mi-croscopy. AJNR Am J Neuroradiol. 2002. 23:1516–1523.

7.Kim HJ., Pyeun YS., Kim YW., Cho BM., Lee TH., Moon TY, et al. A model for research on the blood-brain barrier disruption induced by unsaturated fatty acid emulsion. Invest Radiol. 2005. 40:270–276.

8.Kim HJ., Kim YW., Choi SH., Cho BM., Bandu R., Ahn HS, et al. Triolein emulsion infusion into the carotid artery increases brain permeability to anticancer agents. Neurosurgery. 2016. 78:726–733.

9.Lee IS., Lee JE., Kim HJ., Song JW., Choi SH. Immediate break-down of blood retinal barrier by infusion of triolein emulsion observed by fluorescein angiography. Curr Eye Res. 2011. 36:358–363.

10.Lee JE., Jea SY., Oum BS., Kim HJ., Ohn YH. Effect of fat embo-lism with triolein emulsion on blood-retinal barrier. Oph-thalmic Res. 2009. 41:14–20.

11.Lee JY., Eun CK., Kim YW., Kim HJ., Jung YJ., Jae SY, et al. The steroid effect on the blood-ocular barrier change induced by triolein emulsion as seen on contrast-enhanced MR im-ages. Korean J Radiol. 2008. 9:205–211.

12.Kim YW., Kim HJ., Cho BM., Moon TY., Eun CK. The study of ce-rebral hemodynamics in the hyperacute stage of fat embo-lism induced by triolein emulsion. AJNR Am J Neuroradiol. 2006. 27:398–401.

13.Kim YW., Park YM., Yoon S., Kim HJ., Park DY., Cho BM, et al. Effect of intra-arterial infusion with triolein emulsion on rabbit liver. World J Gastroenterol. 2014. 20:14442–14449.

14.Haenold R., Herrmann KH., Schmidt S., Reichenbach JR., Schmidt KF., Löwel S, et al. Magnetic resonance imaging of the mouse visual pathway for in vivo studies of degeneration and re-generation in the CNS. Neuroimage. 2012. 59:363–376.

15.Chang NK., Jeong YY., Park JS., Jeong HS., Jang S., Jang MJ, et al. Tracking of neural stem cells in rats with intracerebral hemorrhage by the use of 3T MRI. Korean J Radiol. 2008. 9:196–204.

16.Wu B., Wang C., Pang Y., Zhang X. Comparison of SNR calcu-lation methods for in vivo imaging. Available at:. http://cds.ismrm.org/protected/10MProceedings/files/3153_1012.pdf. Accessed Mar 4, 2017.

17.Pfeuffer J., Merkle H., Beyerlein M., Steudel T., Logothetis NK. Anatomical and functional MR imaging in the macaque mon-key using a vertical large-bore 7 Tesla setup. Magn Reson Imaging. 2004. 22:1343–1359.

18.Mezer A., Yeatman JD., Stikov N., Kay KN., Cho NJ., Dougherty RF, et al. Quantifying the local tissue volume and composition in individual brains with magnetic resonance imaging. Nat Med. 2013. 19:1667–1672.

Go to :

Fig. 1.

Surface coils used in the present study. Rat coil (5 cm in diameter) with a rabbit (A) and a rat (B) within the coil. Cat coil (C, 12 cm in di-ameter) and knee coil (D, 15.4 cm in diameter) with a rabbit within the coils.

undefined

Fig. 2.

Brain MR images of a normal rabbit obtained with a rat coil (1), a cat coil (2) and a knee coil (3). T2WI (a), T1WI (b), DWI (c), ADC map image (d), SWI (e) and MRA (f). All MR images obtained with the rat coil reveal good differentiation of the gray/white matter and smoothness of the parenchyma. However, images obtained with the rat coil (1) show better quality compared to those obtained with the cat (2) or knee coil (3). The sharpness of MRA is best on the image obtained with the rat coil (1f) compared to the image obtained with the cat (2f) or knee coil (3f). ADC = apparent diffusion coefficient, DWI = diffusion-weighted image, MRA = MR angiography image, SWI = susceptibility-weighted image, T1WI = T1-weighted image, T2WI = T2-weighted image

undefined

Fig. 3.

Brain MR images of a normal rat obtained with the rat coil (1) and with the cat coil (2). T2WI (a), T1WI (b), DWI (c), ADC map image (d), SWI (e) and MRA (f). MR images obtained with the rat coil (1) reveal better quality in terms of gray/white matter differentiation and smooth-ness compared to those obtained with the cat coil (2). MRA image obtained with the rat coil (1f) shows better sharpness compared to that ob-tained with the cat coil (2f). ADC = apparent diffusion coefficient, DWI = diffusion-weighted image, MRA = MR angiography image, SWI = susceptibility-weighted image, T1WI = T1-weighted image, T2WI = T2-weighted image

undefined

Fig. 4.

MR images of a rabbit (1) and a rat (2) obtained with the rat coil 2 hours after embolization of triolein emulsion into the carotid artery. Embolized hemispheres show mild hyperintensity on T2WI (a), no evidence of diffusion restriction (b, c), no hemorrhage on SWI (d) and diffuse contrast enhancement on Gd-T1WI (e). Lesion conspicuity is better on images obtained from the rabbit (1) compared with those obtained from the rat (2). SWI = susceptibility-weighted image, T1WI = T1-weighted image, T2WI = T2-weighted image

undefined

Table 1.

Parameters of MR Sequences Used in Rabbit MR Brain

	Rat Coil				Cat Coil				Knee Coil
	T2WI	T1WI	DWI	SWI	T2WI	T1WI	DWI	SWI	T2WI	T1WI	DWI	SWI
TR	5440	600	4700	26	6080	600	4700	25	6080	600	4700	25
TE	90	9.3	89	18	93	9.3	89	18	93	9.3	89	18
FA	140	60	90	15	140	60	90	15	140	60	90	15
ST	2	2	2	1	2	2	2	1	2	2	2	1
FOV	50	50	60	50	70	70	60	70	70	70	70	70
NEX	3	2	8	3	4	3	8	2	4	3	8	2
Mat	192	192	76	192	128	128	76	160	128	128	76	160
ET	17	1	45	1	17	1	45	1	17	1	45	1
bV			0, 1000				0, 1000				0, 1000

bV = b value, DWI = diffusion-weighted image, ET = echo train length, FA = flip angle, FOV = field of view, Mat = matrix number, NEX = number of excitation, ST = slice thickness, SWI = susceptibility-weighted image, TE = echo time, TR = repetition time, T1WI = T1-weighted image, T2WI = T2-weighted image

Table 2.

Parameters of MR Sequences Used in Rat MR Brain

	Rat Coil				Cat Coil
	T2WI	T1WI	DWI	SWI	T2WI	T1WI	DWI	SWI
TR	4410	400	4300	26	6080	600	4700	25
TE	99	8.4	113	18	93	9.3	89	18
FA	140	60	90	15	140	60	90	15
ST	2	2	2	1	2	2	2	1
FOV	40	40	60	40	50	50	60	50
NEX	4	2	8	3	4	3	8	2
Mat	192	128	72	192	128	128	76	160
ET	17	1	40	1	17	1	45	1
bV			0, 1000				0, 1000

Table 3.

Signal-To-Noise Ratios of Brain MR Images

	n	T2WI	T1WI	DWI	SWI
Rabbit with rat coil	1	41.2	28.8	12.0	25.4
	2	52.7	38.9	14.0	45.5
	3	48.3	39.9	20.2	24.4
	Mean	47.4	35.9	15.4	31.8
	SD	5.8	6.1	4.3	11.9
Rabbit with cat coil	1	10.4	11.9	7.9	4.8
	2	27.4	15.1	4.3	7.8
	3	30.7	15.0	3.6	7.9
	Mean	22.8	14.0	5.3	6.8
	SD	10.9	1.8	2.3	1.8
Rabbit with knee coil	1	15.6	10.4	5.1	4.5
	2	20.1	12.3	3.6	5.4
	3	20.5	11.6	3.9	5.4
	Mean	18.7	11.4	4.2	5.1
	SD	2.7	1.0	0.8	0.5
Rat with rat coil	1	29.5	29.6	16.8	30.4
	2	10.6	11.6	12.3	12.8
	3	18.6	18.9	9.7	16.9
	Mean	19.6	20.0	12.9	20.0
	SD	9.5	9.1	3.6	9.2
Rat with cat coil	1	7.8	5.6	6.2	9.1
	2	13.5	9.8	6.1	3.2
	3	11.9	8.2	5.7	4.4
	Mean	11.1	7.9	6.0	5.6
	SD	2.9	2.1	0.3	3.1

DWI = diffusion-weighted image, SD = standard deviation, SWI = suscep-tibility-weighted image, T1WI = T1-weighted image, T2WI = T2-weighted image

TOOLS

Similar articles