• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1998년도 추계학술대회
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• pp.96-97
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• 1998

3D TOF MR Angiography is able to obtain thinner slice thickness, higher SNR, therefore higher spatial resolution than 2D TOF MR Angiography. Since it uses longer TR than 2D TOF MRA to allow stronger in-flow effect, the background tissue may not be fully saturated. Thus background tissue signal can be further suppressed by MTS(Magnetization Transfer Saturation). Flow-compensation was accomplished by GMN(Gradient Moment Nulling), and tracking saturation was used to suppress vein signal. The different flow signal at the entry of the slab and output of the slab can be compensated by TONE(Tilted Optimized Non-saturating Excitation) RF pulse.

• Journal of Magnetics
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• 제19권2호
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• pp.185-191
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• 2014

In this study we evaluated that flow rate changes affect the (time of flight) TOF image and contrast-enhanced (CE) in a three-dimensional TOF angiography. We used a 3.0T MR System, a nonpulsatile flow rate model. Saline was used as a fluid injected at a flow rate of 11.4 cm/sec by auto injector. The fluid signal strength, phantom body signal strength and background signal strength were measured at 1, 5, 10, 15, 20 and 25-th cross-section in the experienced images and then they were used to determine signal-to-noise ratio and contrast-to-noise ratio. The inlet, middle and outlet length were measured using coronal images obtained through the maximum intensity projection method. As a result, the length of inner cavity was 2.66 mm with no difference among the inlet, middle and outlet length. We also could know that the magnification rate is 49-55.6% in inlet part, 49-59% in middle part and 49-59% in outlet part, and so the image is generally larger than in the actual measurement. Signal-to-noise ratio and contrast-to-noise ratio were negatively correlated with the fluid velocity and so we could see that signal-to-noise ratio and contrast-to-noise ratio are reduced by faster fluid velocity. Signal-to-noise ratio was 42.2-52.5 in 5-25th section and contrast-to-noise ratio was from 34.0-46.1 also not different, but there was a difference in the 1st section. The smallest 3D TOF MRA measure was $2.51{\pm}0.12mm$ with a flow velocity of 40 cm/s. Consequently, 3D TOF MRA tests show that the faster fluid velocity decreases the signal-to-noise ratio and contrast-to-noise ratio, and basically it can be determined that 3D TOF MRA and 3D CE MRA are displayed larger than in the actual measurement.

• Investigative Magnetic Resonance Imaging
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• 제25권4호
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• pp.323-331
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• 2021

Purpose: To investigate the diagnostic criteria of T1-weighted imaging (T1W) and time-of-flight (TOF) imaging for detecting intraplaque hemorrhage (IPH) of a vertebrobasilar artery (VBA) compared with simultaneous non-contrast angiography and intraplaque hemorrhage (SNAP) imaging. Materials and Methods: Eighty-seven patients with VBA atherosclerosis who underwent high resolution MR imaging for evaluation of VBA plaque were reviewed. The presence and location of VBA plaque and IPH on SNAP were determined. The signal intensity (SI) of the VBA plaque on T1W and TOF imaging was manually measured and the SI ratio against adjacent muscles was calculated. The receiver-operating characteristic (ROC) curve was used to compare the diagnostic accuracy for detecting VBA IPH. Results: Of 87 patients, 67 had IPH and 20 had no IPH on SNAP. The SI ratio between VBA IPH and temporalis muscle on T1W was significantly higher than that in the no-IPH group (235.9 ± 16.8 vs. 120.0 ± 5.1, P < 0.001). The SI ratio between IPH and temporalis muscle on TOF was also significantly higher than that in the no-IPH group (236.8 ± 13.3 vs. 112.8 ± 7.4, P < 0.001). Diagnostic efficacies of SI ratios on TOF and TIW were excellent (AUC: 0.976 on TOF and 0.964 on T1W; cutoff value: 136.7% for TOF imaging and 135.1% for T1W imaging). Conclusion: Compared with SNAP, cutoff levels of the SI ratio between VBA plaque and temporalis muscle on T1W and TOF imaging for detecting IPH were approximately 1.35 times.

• Investigative Magnetic Resonance Imaging
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• 제5권1호
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• pp.38-42
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• 2001

2D TOF혈관조영술에서 presaturation RF펄스를 사용하여 정맥피에서 나오는 MR신호를 제거하고 얻은 동맥 angiogram에는 band형태로 동맥이 끊어져 나타나는 현상이 자주 보인다. 일부 동맥에서 피의 흐름은 한 심장 주기 동안에 3번의 펄스를 갖는데, 이 중 가운데 펄스는 짧은 기간 동안 역류를 한다. 이 역류하는 동맥피는 정맥피와 같은 방향이기 때문에 presaturation RF펄스에 의해 정맥피 처럼 saturation이 되어서 imaging slice로 흘러 들어가게 될 수 있다. 특히 이러한 경우가 phase encoding step의 dc 부근에서 발생하게 되면 그 때의 단면 영상에서 동맥이 강조가 될 수 없게 되어, 결과적으로 angiogram에는 그 단면을 지나는 동맥의 신호가 없어서 band 형태로 핏줄이 끊어져 나타나게 된다. Imaging slice와 saturation band와의 간격을 변화 시켜 가면서 angiogram을 얻어 봄으로서 이러한 현상을 실험적으로 확인하였다 나아가 saturation band를 rectangle형태에서 ramp 형태로 변경함으로써 이러한 artifacts를 제거 할 수 있는 방법을 제시하였다

• Journal of Chest Surgery
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• 제20권3호
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• pp.544-547
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• 1987

Pulmonary vein wedge angiography was applied to two patients of 2 years old TOF with PFO. Left pulmonary artery was not visualized by standard right ventriculogram and catheter was not entered into main pulmonary artery. Through PFO and left atrium, pulmonary vein wedge angiography at left lower pulmonary vein was done. The ipsilateral pulmonary artery & its trees in both cases and the contralateral pulmonary artery in one case were well visualized. Dangerous complication, such as massive bronchoconstriction due to extravasation of contrast material into the bronchus, was not developed. Mild coughing was occurred, but well tolerable in both cases. We recommended a dose of 0.8 mL/Kg of contrast material at a rate of 2 to 3 mL/sec and 1 to 2 mL/Kg of flush solution at the same rate by the hand, and routine use of pulmonary vein wedge angiography in cyanotic patients whose pulmonary artery was not visualized by the standard angiography.

• 대한자기공명의과학회:학술대회논문집
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• 대한자기공명의과학회 2000년도 제5차 추계학술대회
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• pp.29-29
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• 2000

• 대한자기공명의과학회:학술대회논문집
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• 대한자기공명의과학회 1999년도 제4차 추계학술대회 초록집
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• pp.55-56
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• 1999

• 대한자기공명의과학회:학술대회논문집
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• 대한자기공명의과학회 1999년도 제4차 추계학술대회 초록집
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• pp.57-58
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• 1999

• Journal of Chest Surgery
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• 제33권4호
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• pp.290-300
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• 2000

Background: To evaluate the diagnostic accuracy of EBT(Electron Beam Tomography) in the diagnosis of conotruncal anomaly and to determine whether it can be used as a substitute for cardiac angiography. Material and Method: 20 patients(11M & 9F) with TOF(n=7, pulmonary atresia 2), DORV(n=7), complete TGV(n=4), & corrected TGV(n=2) were included. The age ranged from 7 days to 26 years(median 60 days). We analyzed the sequential chamber localization, the main surgical concenrn in each disease category (PA size, LVED volume and coronary artery pattern for TOF & pulmonary atresia, the LV mass, LVOT obstruction, coronary artery pattern for complete TGV, and type of VSD and TV-PV distance for DORV, etc) and other associated anomalies(e.g., VSD, arch anomalies, tracheal stenosis, etc). Those were compared with the results of echocardiography(n=19), angiography (n=9), and surgery(n=11). The interval between EBT and echocardiography/angiography was within 20/11 days, respectively except for an angiography in a patient with corrected TGV (48 days). Result: EBT correctly diagnosed the basic components of conotruncal anomalies in all subjects, compared to echocardiography, angiography or surgery. These included the presence, type and size of VSD(n=20), pulmonic/LV outflow tract stenosis(n=15/2), relation of great arteries and the pattern of the proximal epicardial coronary arteries(16 out of 20). EBT proved to be accurate in quantitation of the intrapericardial and hilar pulmonary arterial dimension and showed high correlation and no difference compared with echocardiography, angiography, or surgery(p>0.05) except for left pulmonary arterial & ascending arterial dimension by echocardiography. LVED volume in seven TOF(no difference: p>0.05 & high correlation: r=0.996 with echocardiography), and LV mass in 4 complete TGV were obtained. Additionally, EBT enabled the cdiagnosis of subjlottic tracheal stenosis and tracheal bronchus in 1 respectively. Some peripheral PA stenosis were not detected by echocardiography, while echocardiography appeared to be slightly more accurate than EBT in detecing ASD or PDA. Conclusion: EBT can be a non-invasive and accurate modality of for the evaluation of most anatomical alteration including peripheral PS or interruption in patients with conotruncal anomalies. Combined with echocardiography, EBT study provides sufficient information for the palliative or total repair of anomalies.

• 대한디지털의료영상학회논문지
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• 제17권1호
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• pp.43-48
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• 2015

Intracrnial 3D TOF MR angiography was performed in 30 normal volunteers with both 1.5 and 3.0 T MRI system with high resolutions. Used Voxel sizes were $0.39{\times}0.39{\times}0.2$(1.5 T) and $0.19{\times}0.19{\times}0.35$(3.0 T), respectively. High image quality and depiction of small vessel branches were equality demonstrated with 1.5 T and 3.0 T HR TOF MRA(p<0.05). Intracranial high resolution TOF MRA with 1.5 T and 3.0 T provides high diagnostic information with having merits and demerits in depiction of vascular branches.