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

• 방사선산업학회지
• /
• 제12권4호
• /
• pp.325-332
• /
• 2018

Carotid angiography covering the aortic arch includes contrast-enhanced magnetic resonance angiography (CEA), which is applied to a large region and usually employs contrast media. However, the use of contrast media can be dangerous in infants, pregnant women, and patients with chronic renal failure (CRF). Follow-up patients informed of a lesion may also want to avoid constant exposure to contrast media. We aimed to apply time-of-flight (TOF) angiography to a large region and compare its usefulness with that of CEA. Ten patients (mean age, 58 years; range, 45~75 years) who visited our hospital for magnetic resonance angiography (MRA) participated in this study. A 3.0 Tesla Achieva magnetic resonance imaging (MRI) system (Philips, Netherland) and the SENSE NeuroVascular 16-channel coil were employed for both methods. Both methods were applied simultaneously to the same patient. Three TOF stacks were connected to cover the aortic arch through the circle of Willis, and CEA was applied in the same manner. For the quantitative assessment, the acquired images were used to set the regions of interest (ROIs) in the common carotid artery (CCA) bifurcation, internal carotid artery, external carotid artery, middle cerebral artery, and vertebral artery, and to obtain the signal-to-noise ratio (SNR) and the contrast-to-noise ratio (CNR) for the soft tissues. Three radiologists and one radiological resident performed the qualitative assessment on a 5-point scale - 1 point, "very bad"; 2 points, "bad"; 3 points, "average"; 4 points, "good"; and 5 points, "very good" - with regard to 4 items: (1) sharpness, (2) distortion, (3) vein contamination, and (4) expression of peripheral vessels. For the quantitative assessment, we estimated the mean SNR and CNR in each of the 5 ROIs. In general, the mean SNR was higher in TOF angiography (166.1, 205.2, 154.39, 172.23, and 161.95) than in CEA(92.05, 95.43, 84.76, 73.69, and 88.3). Both methods had a similar mean CNR: 67.62, 106.71, 55.9, 73.74, and 63.46 for TOF angiography, and 67.82, 71.19, 60.52, 49.45, and 64.07 for CEA. In all ROIs, the mean SNR was statistically significant (p<0.05), whereas the mean CNR was insignificant (p>0.05). The mean values of TOF angiography and CEA for each item in the qualitative assessment were 4.2 and 4.28, respectively for item 1; 2.93 and 4.55, respectively, for item 2; 4.6 and 3.13, respectively, for item 3; and 2.88 and 4.65, respectively, for item 4. Therefore, TOF angiography had a higher mean for item 3, and CEA had a higher mean for items 2 and 4; there was no significant difference between the two methods for item 1. The results for item 1 were statistically insignificant (p>0.05), whereas the results for items 2~4 were statistically significant (p<0.05). Both methods have advantages and disadvantages and they complement each other. However, CEA is usually applied to a large region covering the aortic arch. Time-of-flight angiography may be useful for people such as infants, pregnant women, CRF patients, and followup patients for whom the use of contrast media can be dangerous or unnecessary, depending on the circumstance.

• 대한디지털의료영상학회논문지
• /
• 제14권1호
• /
• pp.7-12
• /
• 2012

The purpose of this study was to examine usefulness of 3T equipment-based time-of-flight magnetic resonance angiography (3T-TOF MRA) by comparing standard technique (ST) with high resolution technique (HRT) in evaluation of cerebral blood vessel. The 3T-TOF MRA was performed for 31 patients who were suspected of having cerebrovascular disease from March to July 2010. For evaluation of cerebral blood vessel, classification was conducted randomly: group I that included vertebral artery and basilar artery, group II that ranged from 2.5cm before basin part of common carotid artery to basin part of internal and external carotid arteries and to genu part of internal carotid artery, group III that ranged from vertebral part of internal carotid artery to the first basin art of anterior and middle cerebral through education recognizes the importance of dose reduction and examine if their efforts and further reduce patient dose could achieve optimization of the medical exposure is considered.

• Investigative Magnetic Resonance Imaging
• /
• 제9권2호
• /
• pp.94-100
• /
• 2005

목적 : 뇌혈관 평가에 있어서 경두개 도플러 초음파(transcranial doppler; TCD)와 고식적 뇌혈관조영술(CA)과 비교하여 3T 장비를 이용한 Time-of-flight(TOF) 자기공명 뇌혈관 조영술(3T-TOF MRA)의 유용성에 대해 알아보고자 하였다. 대상 및 방법 : 뇌혈관 질환이 의심된 54명의 환자를 대상으로 3T-TOF MRA를 시행하였다. 54명 모두에서 TCD를 시행하였으며, 이중 11명은 CA를 함께 시행하였다. 뇌혈관의 평가를 위해 추골동맥과 기저동맥을 포함하여 I군, 총경동맥의 분지부위 2 cm 전부터 내 외경동맥 분지 부위에서 내경동맥의 무릎(genu)부위 까지를 II군, 내경동맥의 추체부위에서 전 중 대뇌동맥의 1차분지 부위까지를 III군, 그리고 각각 전 중 대뇌동맥 1차분지 그 이하 부위를 IV군으로 임의로 구분하였다. 평가는 2명의 방사선과 의사가 3T-TOF MRA와 TCD, 그리고 CA의 결과를 모르는 상태에서 각 군에서 혈관의 양상이 잘 나타나는 경우를 3점, 양상이 잘 나타나지 않으나 판독이 가능한 경우를 2점, 잡상 등으로 혈관의 평가가 어려운 경우를 1점으로 하였다. 혈관의 협착 정도에 대한 평가는 TCD 및 CA와 각각 비교하여 그 일치 정도를 평가하였다. 결과 : 각 군당 좌우를 합하여 108 혈관분절, 총 432 혈관분절을 평가하였다. 정성평가에서 I, II, III, IV군은 각각 2.98, 2.96, 2.91, 2.88로 혈관의 양상에 대한 파악은 잘 되는 것으로 나타났다. TCD만을 시행한 43명 중 41명에서 3T-TOF MRA와 TCD가 일치하였고, TCD와 CA를 모두 함께 시행한 11명에서는 3T-TOF MRA가 TCD 및 CA와 모두 일치하였다. 결론 : 3T-TOF MRA는 뇌혈관 평가에 있어서 CA 및 TCD와 비교해서 빠르고 비침습적이며 혈관상태를 적절하게 평가할 수 있는 유용한 검사라고 생각한다.

• 한국임상수의학회:학술대회논문집
• /
• 한국임상수의학회 2008년도 추계학술대회
• /
• pp.155-155
• /
• 2008

• 대한디지털의료영상학회논문지
• /
• 제15권1호
• /
• pp.1-7
• /
• 2013

Purpose : The Carotid Angio inspection including Aortic arch applied to wide area is conducted as the Contrast Enhance MR Angiography(CEA) which is using a contrast medium. However it is a burden not only for someone such as infants, pregnant women and patients suffering from kidney failure but continuous use of contrast medium also can be a burden for patients who has been taken follow up inspection since diagnose lesion already. The purpose of this study is to estimate a usefulness of the Time of Flight (TOF) by comparing with CEA. Materials and methods : 10 patients with an average age of 58 (from 45 to 75) who had MRA inspection in our hospital were studied using 3.0 Tesla Aachieva (Philips, Netherland) MRI system and Sense Neuro-Vascular 16 Channels Coil. The same patient was inspected both TOF and CEA simultaneously. The TOF inspection included from Aortic arch to Willis Circle by connecting 3 TOF stacks and so did CEA inspection. The quantitative analysis was conducted through signal to noise ratio(SNR) and contrast to noise ratio(CNR) with soft tissue by setting up an area of interest on CCA bifurcatoin, ICA, ECA, MCA and VA concerning obtained image. In case of qualitative analysis, 3 radiological technologists and 1 radiologist evaluated 4 items (1: Visibility of the blood vessel, 2: Image distortion measure, 3: Overlapping measure with vein, 4: Peripheral blood vessel description measure) into five points scale (1: Very bad, 2: Bad, 3: Normal 4: Good, 5: Very good). Results : Results for the quantitative analysis was obtained by calculating the average of 5 ROIs in case of SNR and CNR separately. Results of SNR, TOF were generally measured higher than CEA (In case of TOF were 166.1, 205.2, 154.39, 172.23, 161.95, and CEA were 92.05, 95.43, 84.76, 73.69, 88.3). But according to the result of CNR, both TOF and CEA were measured similarly as 67.62, 106.71, 55.9, 73.74, 63.46 for TOF and 67.82, 71.19, 60.52, 49.45, 64.07 for CEA. Throughout every results of each ROI, SNR showed statistically meaningful consequence (0.050.05). In case of qualitative analysis the average of each evaluated item was 4.2points and 4.28points in the item1, 2.93points and 4.55points in the item2, 4.6points and 3.13points in the item3, 2.88points and 4.6points in the item4. According to the results TOF was measured higher in the item3 while in the item2 and item4 CEA was higher and in case of the item1, both CEA and TOF were similar. To sum up statistically meaningful results (p<0.05) were shown in the item2, item3 and item4 but not in the item1 (p>0.05). Conclusions : Both TOF and CEA are complementary because each inspection has pros and cons, but when inspect wide area including Aortic arch normally CEA is conducted. But TOF inspection also can be considered as alternative in terms of patients who has difficulty in the contrast medium such as infants, pregnant women and patients suffering from kidney failure and patients during follow up.

• Investigative Magnetic Resonance Imaging
• /
• 제8권1호
• /
• pp.17-23
• /
• 2004

목적 : 이차원 위상대조 자기공명영상을 이용하여 나이변화와 뇌실질 부피변화 및 혈관이상의 정도에 따른 총뇌혈류량의 변화를 알고자 하였다. 대상 및 방법 : 12명의 지원자를 포함한 73명을 대상으로 T2강조 영상과 Time-of-flight 방법의 자기공명혈관촬영과 이차원 위상대조 자기공명영상을 얻었다. 정상군은 지원자 12명과 자기공명영상 및 자기공명혈관촬영에서 정상소견을 보인 21명으로서 이들은 18-29세, 30-49세, 50-66세 군으로 나누었다. 비정상군은 T2강조영상의 뇌실질부피 변화정도와 자기공명 혈관촬영의 동맥경화 정도에 따라 mild reduction군(17명) , marked reduction군(12명)으로 나누었고, 뇌실질이 증가한 increased volume군(6명)과 Moya-moya군(5명)으로 분류하였다 뇌혈류는 위상대조 자기공명영상의 속도-혈류 곡선으로부터 양쪽 내경동맥과 추골동맥에서 측정하고 합하여 뇌의 총뇌혈류량으로 하였으며, 각군 사이의 혈류량을 비교 관찰하였다. 결과 정상군의 총뇌혈류량은 18-29세군은$12.0{\pm}2.1ml/sec$, 30-49세군은 $11.8{\pm}1.9m1/sec$, 50-66세군은 $10.9{\pm}2.2ml/sec$였다. 비정상군 중에서 mild reduction 군은 $9.5{\pm}2.5ml/sec$, marked reduction 군은 $7.6{\pm}2.0ml/sec$, increased volume군은 $7.3{\pm}1.2ml/sec$, Moya-moya군은 $7.0{\pm}1.1ml/sec$였다. 결론 : 총뇌혈류량은 나이 증가에 따라 감소하였고, 뇌실질부피 감소와 동맥경화 정도에 따라 감소하였으며 increased volume군과 Moya-moya군에서도 감소하였다. 이차원 위상대조 자기공명영상은 나이변화나 뇌실질의 부피변화와 혈관이상을 초래하는 다양한 뇌질환에서 총뇌혈류량을 관찰할 수 있는 유용한 방법이라고 생각된다.

• Annals of Clinical Neurophysiology
• /
• 제10권2호
• /
• pp.104-108
• /
• 2008

Background: The compression of 7th cranial nerve by arteries is one of the various causes of hemifacial spasm (HFS). A few previous studies were revealed the relation between the compression of 7th cranial nerve and common trunk anomaly. We evaluated the common trunk anomalies in patients with HFS using MRI and MRA. Methods: From January 2001 to December 2005, 41 consecutive patients (9 men, mean age $54.5{\pm}12.6$) with HFS underwent MRI and MRA. T2 axial images and time-of-flight angiographies were reviewed for identification of the compression at root exit zone by two neuroradiologists and one neurologist. Results: Thirty-seven patients showed neurovascular compression on the lesion side. Twenty patients of them were shown the compression of 7th cranial nerve by anterior inferior cerebellar artery (AICA), and seventeen patients of them were shown the compression by posterior inferior cerebellar artery (PICA). Twenty-four patients of the thirty-seven patients had common trunk anomaly. In control, twelve of twenty-one subjects had common trunk anomaly, that the frequencies of common trunk anomaly of two groups were 58.8% in HFS and 57.1% in controls. In the twenty-four patients with common trunk anomaly, eighteen patients had dominant-AICA, and six patients had dominant-PICA. The rate of nerve compression by common trunk anomaly in the HFS with unilateral common trunk, dominant-AICA was 76.5% and dominant-PICA was 100%. Conclusions: This study also revealed that AICA was most common compressive artery. There was no difference between the HFS groups and control groups in frequency of common trunk anomaly. Thus, we could not demonstrate the relationship between common trunk anomaly and HFS.

• Journal of Korean Neurosurgical Society
• /
• 제52권2호
• /
• pp.85-91
• /
• 2012

Objective : Hemifacial spasm (HFS) caused by vertebrobasilar dolichoectasia (VBD) is very rare, and in theses cases, it is difficult to decompress the nerve from its vascular compression. The objective of this study was to investigate the outcome of microvascular decompression (MVD) for HFS caused by VBD. Methods : There were 10 patients of HFS caused by VBD at our hospital between September 1978 and September 2008. We evaluated magnetic resonance angiography (MRA) and time of flight magnetic resonance imaginge (TOF MRI) findings using the criteria for VBD. We compared the clinical outcomes of MVD for the 10 patients with VBD with the overall outcomes of the total 2058 MVDs performed for HFS. Results : The results of MVD for HFS caused by VBD were successful in 90.9% of cases. The postoperative complication rate in VBD was 45.5%. Offending vessels in patients with VBD were identified visually during surgery. Adverse effects after MVD were found in 4 patients. We found that the diameter of VBD was significantly greater in patients with complications than in those with no complications (p=0.028). Conclusion : Our data shows that MVD may be a good treatment modality for HFS caused by VBD but care must be taken to avoid adverse effects from the procedure. It is important to detach the dolichoectatic artery from its surrounding structures sufficiently to allow it to be easily movable. In addition, attempts should be made to lessen the retraction of the cerebellum during release of the dolichoectatic artery.

• 대한영상의학회지
• /
• 제84권6호
• /
• pp.1361-1366
• /
• 2023

잔류 원시 후각동맥은 1979년에 처음 보고된 매우 드문 전대뇌동맥의 변이로, 급격하게 꺾이는 머리핀 회전의 구조적 특성에 의하여 혈역학적 스트레스가 유발되고, 이로 인하여 동맥류의 발생과 높은 연관성을 가지는 것으로 보고되고 있다. 우리는 간헐적 두통을 주소로한 46세 여성에서 우연히 발견된 머리핀 회전에서 동맥류를 동반한 제4형 잔류 원시 후각 동맥의 증례에 대하여 보고하고자 한다. 뇌 MRA와 유체속도강조 자기공명혈관조영술(time-offlight MR angiography)에서 왼쪽 전대뇌동맥의 A1 분절에서 시작되어 머리핀 회전을 형성한 후 부 중대뇌동맥으로 이어지는 비정상적인 주행을 보이는 동맥이 확인되었다. 또한 머리핀 회전 분절에서 방추형 동맥류도 확인이 되었다. 이러한 변이들은 극히 드물긴 하지만, 동맥류가 동반될 수 있음을 인지하고 진단하는 것이 중요하다.