Development of multi-band imaging method and its application to peripheral MR angiography다단면 동시 영상 기법 개발과 하반신 혈관 자기공명영상에의 적용

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For acceleration of imaging time, parallel imaging (PI) techniques (e.g., SENSE, GRAPPA) utilize the sensitivity differences of the multi-channel RF coil in the intra slice, and multi-band imaging techniques (e.g., CAIPI-RINHA) use them in the slice selection direction. Since the conventional multi-band imaging and PI techniques do not fully utilize the sensitivity differences of the multi-channel RF coil, we propose a new multi-band imaging technique, the so-called multi-slice image generation using intra-slice parallel imaging and inter-slice shifting (MAGGULLI). In addition, we proposed a new peripheral magnetic resonance angiography (MRA) technique that possesses a high contrast between the vessel and the background without using electrocardiography (ECG) triggering and saturation RF pulses. This work consists of two parts: first, we propose a new multi-band imaging method, so-called MAGGULLI. In MAGGULLI, we use an inter-slice shifting gradient to make the inter-slice shift in the RO direction. Thus, aliasing caused by under-sampling in the PE direction is orthogonal to that by multi-band imaging with the inter-slice shifting, both of which are resolved by using the sensitivity information of the RF coil. Second, a new peripheral MRA technique is presented which is based on the velocity selective (VS) RF excitation technique and golden-angle radial sampling scheme. Because of the sinusoidal excitation profile with respect to the velocity of VS ex-citation technique, the magnitude of signal is varied by the velocity of the blood flow. By using time varying signals in arterial region, acquired data is categorized into the data acquired at systole and diastole phases, re-spectively and two images are reconstructed from systole and diastole phase data. Reconstructed images from systole and diastole phases are subtracted to eliminate background with field inhomogeneity, and vein signal. Further, the conjunction of MAGGULLI and the proposed peripheral MRA is presented to reduce the imaging time of the proposed peripheral MRA. To show the performance of MAGGULLI, Phantom and in-vivo imaging experiments demonstrate that the quality of the images reconstructed by MAGGULLI are better than that of CAIPIRINHA, especially for high acceleration factors. Further, the results of g-factor analysis show that the proposed method produces a better g-factor than CAIPIRINHA in all tested AFs with a reasonable slice distance. Also, in-vivo experiment results of the proposed peripheral MRA and QISS is presented. In-vivo imaging experiments demonstrated that the pro-posed peripheral MRA generated less residual venous and background signals than QISS. Furthermore, the re-sults of apparent contrast and relative CNR analysis showed that the proposed method produced a better con-trast than QISS in all tested regions and subjects.
Advisors
Park, Hyun Wookresearcher박현욱researcher
Description
한국과학기술원 :전기및전자공학부,
Publisher
한국과학기술원
Issue Date
2016
Identifier
325007
Language
eng
Description

학위논문(박사) - 한국과학기술원 : 전기및전자공학부, 2016.8 ,[ix, 93 p. :]

Keywords

CAIPIRINHA; Inter-slice shifting; Multi-band imaging; Parallel imaging; Non-contrast enhanced peripheral MRA; Golden-angle radial sampling; Velocity-selective excitation; 다단면동시영상기법; 병렬영상기법; 조영제 없는 혈관조영술; 속도 선택 신호 획득 기법; 하반신 혈관조영술

URI
http://hdl.handle.net/10203/222317
Link
http://library.kaist.ac.kr/search/detail/view.do?bibCtrlNo=663167&flag=dissertation
Appears in Collection
EE-Theses_Ph.D.(박사논문)
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