• Title/Summary/Keyword: T1영상

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Study on the Physical Imaging Characteristics by Using Magnetic Resonance Imaging 1.5T (1.5T 자기공명영상을 이용한 물리적 영상 특성에 대한 연구)

  • Min, Jung-Whan;Jeong, Hoi-Woun;Han, Ji-Hyun;Lee, Si-Nae;Park, Jang-Ho;Kim, Ki-Won;Kim, Hyun-Soo
    • Journal of radiological science and technology
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    • v.42 no.5
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    • pp.329-334
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    • 2019
  • This study was purpose to quantitative evaluation of noise power spectrum(NPS) and studied the quantitative evaluation and characteristics of modulation transfer function(MTF) by obtain the optimal edge image by using Coil in magnetic resonance imaging(MRI) equipment through Fujita theory using edge method. The MRI equipment was used (Tim AVANTO 1.5T, Siemense healthcare system, Germany) and the head matrix coil were 12channels(elements) receive coil. The NPS results of showed the best value of 0.004 based on the T2 Nyquist frequency of $1.0mm^{-1}$, and the MTF results of showed that the T1 and T2 values were generally better than the T1 CE and T1 CE FC values. The characteristics of this study were to explain the characteristic method of image quality evaluation in general. To present the quantitative evaluation process and results in the evaluation of MRI image characteristics in radiology.

Assesment Of Image Quality in the Abdominal Magnetic Resonance Imaging: Comparison with 1.5 T and 3.0 T (복부 자기공명영상에서 영상의 질 평가: 1.5 T 와 3.0 T 비교)

  • Goo, Eun-Hoe
    • Journal of the Korean Society of Radiology
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    • v.10 no.5
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    • pp.367-373
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    • 2016
  • This study conducted an analysis to compare the differences in the properties of the magnetic field and the generation of artifacts because of the difference in the magnetic field between 1.5 T equipment and 3.0 T equipment, centering around four types of pulse sequences, mainly applied to the abdominal Magnetic Resonance Imaging (MRI). With data on 500 persons transmitted to the PACS, this study analyzed the SNR value, quantitatively and carried out a qualitative evaluation, dividing MSA, CSA, and DA into three steps. As a result of the quantitative evaluation, the SNR value was significantly higher in the 1.5 T equipment; however, there was a factor deteriorating the image quality, too, as artifacts were generated in the images. The 1.5 T equipment generated fewer artifacts than the 3.0 T equipment did, so it could compensate the image quality for 3.0 T. In conclusion, based on these findings, this study could understand the differences in the properties of the magnetic field and the generation of artifacts occurring because of the difference in the magnetic field and could provide a measure for them. This study would be guidelines for MRI users who directly examine the patients in abdominal MRI using the two types of equipment in the clinical setting in the future.

Female External Genitalia and Urethra on MR Imaging: Optimal Pulse Sequence and Comparison of Anatomy in Premenopausal and Postmenopausal Women (여성 외부 생식기와 요도의 자기공명영상 소견: 적합한 영상기법과 폐경 전후의 해부학적 변화 비교)

  • Whang, Shin-Young;Ahn, Kyung-Sik;Sung, Deuk-Jae;Park, Beom-Jin;Kim, Min-Ju;Cho, Sung-Bum;Lee, Nam-Joon
    • Investigative Magnetic Resonance Imaging
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    • v.15 no.2
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    • pp.146-153
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    • 2011
  • Purpose : To describe normal anatomy and compare the differences of external genital organs and urethra on MR imaging in pre- and postmenopausal women. Materials and Methods : A total of 19 pre- and 18 postmenopausal healthy women underwent pelvis MR imaging at 1.5 T. Two radiologists retrospectively scored and compared the image quality of female external genitalia and urethra on axial T2-weighted images (T2WI) and axial fat-suppressed contrast-enhanced T1-weighted images (FSCE-T1WI) by using Wilcoxon signed ranks test. The radiologists compared the wall thickness or size of external genital organs and urethra on FSCE-T1WI between two groups by using Student t test. Results : Image quality was better with FSCE-T1WI than with T2WI in all subjects (p < 0.05). The vestibular bulb, clitoris and labium minor were more clearly visualized on FSCE-T1WI in premenopausal subjects rather than in postmenopausal subjects (p < 0.05). The urethra had a target-like appearance with three layers in premenopausal and postmenopausal subjects. Postmenopausal subjects were observed to have significantly smaller vaginal wall thickness, urethral wall thickness and vestibular bulb width than premenopausal subjects (p < 0.05). Conclusion : The anatomy and morphologic changes of female external genital organs and urethra were well discernible on FSCE-T1WI.

Comparative Study of a Multi-Channel Coils of Magnetic Resonance Imaging(MRI) Signal Intensities under Identical Parameters (동일한 조건의 자기공명검사에서 코일의 채널수 변화에 따른 신호강도의 평가)

  • Son, Soon-Yong
    • The Journal of the Korea Contents Association
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    • v.19 no.6
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    • pp.418-423
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    • 2019
  • The purpose of this study was to determine how the different number of channels of coils were related in the perceived signal intensity under identical parameters and area. Dedicated knee phantoms were scanned consecutively using both of the 16-channel and 8-channel knee coils. The T1 weighted and T2 weighted sequences were acquired using both coils to compare the signal intensities according to the number of channels. As a result, the 16-channel knee coils outperformed the 8-channel knee coils and the signal intensity was significantly increased in both of the T1 and T2 weighted images with the 16-channel coil. In conclusion, it is considered that better signal intensities and more clinical utility can be provided, when coils with more number of channels are used rather than using the coils with smaller number of channels.

The Detection of Intracranial Calcification by MR : Experimental Model (실험적 모델을 이용한 자기공명영상에서 석회화의 인지)

  • 박승진
    • Progress in Medical Physics
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    • v.5 no.1
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    • pp.3-12
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    • 1994
  • Purporse : It is known that detection of calcification by MRI is difficulty in intracranial calcified lesions, but author tried to evaluate the signal intensity image of calcification by MR with experimental model. Subjects & Methods : Author analyzed and compared with values of calcium carbonate and hydroxyapatite phantoms by each concentration (10, 20, 30, 40, 50%) and size(1-10mm), measured ROI attenuating from CT and MRI(TlWI & T2WI). Results : The high concentration of calcium carbonate is, the lower the signal intensity of calcium carbonate phantom is both T1 & T2WI. For concentration of Hydroxyapatite of up to 30% by weight the signal intensity on standard T1 weighted images increased but subsequently decreased. Hyperintensity does not preclude calcification as a cause of the signal alteration-an observation that all radiologists interpreting MR images need to be aware of. Conclusion: The signal intensity of intracranial calcification is various on MR imaging in concerning with components, concentration, & size of calcification, and especially high signal intensity of intracranial calcification noted differencial diagnosis.

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Assessment of Imaging Distortion in Magnetic Resonance Imaging for Stereotactic Radiosurgery: Through Phantom Study (뇌정위 방사선수술 시스템을 위한 자기공명영상의 공간적 왜곡의 측정 : 모형실험을 통한 연구)

  • 박선원;한문희;김동규;정현태;송인찬
    • Investigative Magnetic Resonance Imaging
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    • v.4 no.1
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    • pp.7-13
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    • 2000
  • Purpose : To assess the distortion of MRI with the Leksell stereotactic radiosurgery system in variable pulse sequence and imaging plane through phantom study, to find most adequate imaging plane and pulse sequence for stereotactic radiosurgery system. Materials and methods : We made the phantoms for MRI and get images in variable conditions and analyzed the image distortion using image analysis program, and statistically using paired student t-test. Results : The transeverse plane images had acceptable error ranges bless than 1.5mm) in all pulse sequence in both the analysis of fiducial marker in stereotactic G-frame and the phantom study. The coronal plane images had unacceptable large errors (more than 1.7mm) in the analysis of fiducial marker in the stereotactic G-frame, but had corrected small errors (less than 1.5mm) in the phantom study. Conclusion : We find from the phantom study that the present MR machines are adequate for stereotactic surgery system in frequently used pulse sequences, and imaging planes.

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Clinicoradiologic Characteristics of Intradural Extramedullary Conventional Spinal Ependymoma (경막내 척수외 뇌실막세포종의 임상 영상의학적 특징)

  • Seung Hyun Lee;Yoon Jin Cha;Yong Eun Cho;Mina Park;Bio Joo;Sang Hyun Suh;Sung Jun Ahn
    • Journal of the Korean Society of Radiology
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    • v.84 no.5
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    • pp.1066-1079
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    • 2023
  • Purpose Distinguishing intradural extramedullary (IDEM) spinal ependymoma from myxopapillary ependymoma is challenging due to the location of IDEM spinal ependymoma. This study aimed to investigate the utility of clinical and MR imaging features for differentiating between IDEM spinal and myxopapillary ependymomas. Materials and Methods We compared tumor size, longitudinal/axial location, enhancement degree/pattern, tumor margin, signal intensity (SI) of the tumor on T2-weighted images and T1-weighted image (T1WI), increased cerebrospinal fluid (CSF) SI caudal to the tumor on T1WI, and CSF dissemination of pathologically confirmed 12 IDEM spinal and 10 myxopapillary ependymomas. Furthermore, classification and regression tree (CART) was performed to identify the clinical and MR features for differentiating between IDEM spinal and myxopapillary ependymomas. Results Patients with IDEM spinal ependymomas were older than those with myxopapillary ependymomas (48 years vs. 29.5 years, p < 0.05). A high SI of the tumor on T1W1 was more frequently observed in IDEM spinal ependymomas than in myxopapillary ependymomas (p = 0.02). Conversely, myxopapillary ependymomas show CSF dissemination. Increased CSF SI caudal to the tumor on T1WI was observed more frequently in myxopapillary ependymomas than in IDEM spinal ependymomas (p < 0.05). Dissemination to the CSF space and increased CSF SI caudal to the tumor on T1WI were the most important variables in CART analysis. Conclusion Clinical and radiological variables may help differentiate between IDEM spinal and myxopapillary ependymomas.

Analysis of the Dental Implants MRI Artifacts by Using the ACR Phantom (ACR 팬텀을 이용한 치아 임플란트 자기공명영상 인공물 분석)

  • Shin, Woon-Jae
    • Journal of the Korean Society of Radiology
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    • v.10 no.8
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    • pp.629-635
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    • 2016
  • ACR phantom for quality control of magnetic resonance imaging equipment can evaluate magnetic resonance imaging picture quality through various structures within the phantom. In this study, percent Signal Ghosting and Slice position accuracy of imaging could be analyzed by attaching implant and the wire for correction of tooth using ACR phantom in Head coil of 3.0T equipment. In the T1 weighted imaging of the first slice and the eleventh slice of implant, the slice position accuracy appeared to be good in ingress bandwidth 300, and it was good in ingress bandwidth 130 when wire for correction was attached. Percent Signal Ghosting in the seventh slice of SE T1 weighted imaging, implant and wire for correction added all appeared to be good when ingress bandwidth was 230. It is thought that in case of implant dental prosthesis patients in brain exam using magnetic resonance imaging, optimum image can be obtained by changing ingress bandwidth.

An effectiveness of multitransmit parallel technique on scan time reduction in hip joint MRI (고관절 자기공명영상 검사 시 multitransmit 기법의 적용에 따른 검사시간 단축의 유용성)

  • Choi, Kwan-Woo;Son, Soon-Yong
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.17 no.3
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    • pp.103-108
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    • 2016
  • This study examined the effectiveness of the multitransmit parallel technique on the MRI scan time reduction by removing the dielectric effect. The T1 and T2 weighted images of the patients' hip joint were acquired with and without a multitransmit technique. The ROIs were located in the head of femur and iliopsoas muscle. The SNR, CNR and scan time were measured and compared. There was no difference in the images with and without multitransmit. In contrast, the acquisition time was decreased by 42.8% in T1WI and 49.7% in T2WI. In conclusion, this study demonstrated that significant scan time reductions can be accomplished without any differences in the image quality in hip joint MRI by applying the multitransmit parallel technique. Furthermore, the multitranstmit technique is useful in other body parts to resolve the long scan time of an MRI examination.

The Evaluation of Image Quality in Gradient Echo MRI of the Pancreas : Comparison with 2D T1 FFE and 3D T1 THRIVE Imaging (췌장 경사자기장에코 자기공명영상에서 영상의 질 평가)

  • Goo, Eun-Hoe
    • Journal of the Korean Society of Radiology
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    • v.10 no.2
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    • pp.73-79
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    • 2016
  • The purpose of this analysis is to compare 2D T1 FEE and 3D T1 THRIVE for demonstration of the pancreas. A total of 85(45 men, 40 women; 58 years) PACS network datum were analysis clinically indicated pancreas MRI at 1.5 T. The SNRs and CNRs of 3D T1 THRIVE(SNR: $46.42{\pm}0.67$, CNR: $28.16{\pm}0.50$) showed significantly higher values than those from 2D T1 FEE(SNR: $53.84{\pm}1.20$, CNR: $35.48{\pm}0.70$), p<0.05, The image quality of the 3D T1 THRIVE($2.63 {\pm}0.14$) was significantly superior to that with the 2D T1 FEE($2.2{\pm}0.05$), but 3D T1 THRIVE revealed several artifacts resulting in poor quality. In conclusion, The 3D T1 THRIVE technique with a 1.5 T resulting in improved SNRs, CNRs and image quality was demonstrated.