• 제목/요약/키워드: Magnetic Resonance Angiography

검색결과 282건 처리시간 0.04초

k-t FOCUSS 알고리듬을 이용한 고분해능 4-D MR 혈관 조영 영상 기법 (High Resolution Time Resolved Contrast Enhanced MR Angiography Using k-t FOCUSS)

  • 정홍;김응엽;예종철
    • Investigative Magnetic Resonance Imaging
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    • 제14권1호
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    • pp.10-20
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    • 2010
  • 목적: 최근, 미국 애리조나 세도나에서 열린 국제자기공명학회 (ISMRM) 주관의 2009년 데이터 샘플링과 영상 복원에 관한 워크샵에서 자기공명영상 복원 대회가 열렸다. 이 대회는 time resolved contrast enhanced MR angiography 에 대한 고속 촬영의 실제 활용 가능성을 평가하기 위한 것이었다. 본 논문은 이 대회의 우승 결과를 얻은 k-t FOCUSS 알고리듬을 단계별로 자세히 묘사하도록 한다. 대상 및 방법: 본 그룹은 앞선 연구에서 비교적 덜 스파스한 심장 영상에 대해 k-t FOCUSS 알고리듬이 성공적으로 압축센싱 문제를 풀수 있음을 증명했다. 따라서 k-t FOCUSS 알고리듬을 time resolved contrast enhanced MR angiography 에 적용함으로써, 매우 정확한 영상 복원이 가능할 것이다. 영상 복원을 위해 X-ray 대뇌 혈관조영 영상으로부터 구성된 다운 샘플링된 데이터가 대회 주최측으로부터 공통으로 제시되었고, 방사선과 의사들이 각 복원된 영상에 대한 사전 정보 없이, 원래 영상과 복원된 결과를 비교함으로써, 영상의 질을 평가하였다. 결과: 다양한 다운샘플링에 대해 얻어진 결과들은 영상의 스파스 변환이나 샘플링 형태와 같은 압축센싱의 중요한 요소들에 의해 크게 영향을 받는다는 것을 보여주었다. 결론: 복원된 결과로부터, 압축센싱 동적자기공명영상 기법인 k-t FOCUSS 가 고해상도의 time resolved contrast enhanced MR angiography 를 가능하게 할 수 있음을 확인하였다.

Lung Perfusion Imaging and $Tc^{99m}-Macroaggregated$ Human Serum Albumin

  • Haider, Kh.H.;Ilyas, M.;Hyder, Q.;Kim, Chong-Kook
    • Journal of Pharmaceutical Investigation
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    • 제31권2호
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    • pp.73-80
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    • 2001
  • Lung perfusion scanning, invariably combined with ventilation studies provides a reliable and non-invasive mean to diagnose lung related pathologies despite the availability of modern techniques such as angiography, magnetic resonance imaging, magnetic resonance angiography, and helical (spiral) computed tomography. The technique involves the generation of images by radiations emitted from radioisotopes introduced in to the lungs. Various radiopharmaceuticals have been proposed and designed to incorporate $Tc^{99m}$ in to macroparticulate form for lung perfusion imaging. However, most of these have associated difficulties such as reproducibility of the product with regards to particle size distribution and poor elimination from the lung capillary bed. $Tc^{99m}$ macroaggregated albumin $(Tc^{99m}-MAA)$ is used extensively for clinical lung perfusion imaging and is considered as the radiopharmaceutical of choice. It is non-toxic, safe, and being biodegradable, is easily eliminated from the lung capillary bed by proteolytic enzyme metabolism and by mechanical forces due to lung movement.

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Complete occlusion of the right middle cerebral artery associated with Mycoplasma pneumoniae pneumonia

  • Kang, Ben;Kim, Dong Hyun;Hong, Young Jin;Son, Byong Kwan;Lim, Myung Kwan;Choe, Yon Ho;Kwon, Young Se
    • Clinical and Experimental Pediatrics
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    • 제59권3호
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    • pp.149-152
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    • 2016
  • We report a case of a 5-year-old girl who developed left hemiparesis and left facial palsy, 6 days after the initiation of fever and respiratory symptoms due to pneumonia. Chest radiography, conducted upon admission, showed pneumonic infiltration and pleural effusion in the left lung field. Brain magnetic resonance imaging showed acute ischemic infarction in the right middle cerebral artery territory. Brain magnetic resonance angiography and transfemoral cerebral angiography revealed complete occlusion of the right middle cerebral artery. Mycoplasma pneumoniae infection was identified by a 4-fold increase in IgG antibodies to M. pneumoniae between acute and convalescent sera by enzyme-linked immunosorbent assay. Fibrinogen and D-dimer levels were elevated, while laboratory exams in order to identify other predisposing factors of pediatric stroke were all negative. This is the first reported pediatric case in English literature of a M. pneumoniae-associated cerebral infarction involving complete occlusion of the right middle cerebral artery.

Diverse imaging characteristics of a mandibular intraosseous vascular lesion

  • Handa, Hina;Naidu, Giridhar S.;Dara, Balaji Gandhi Babu;Deshpande, Ashwini;Raghavendra, Raju
    • Imaging Science in Dentistry
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    • 제44권1호
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    • pp.67-73
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    • 2014
  • Intraosseous vascular lesions of the maxillofacial region are rare, and the differential diagnosis of intraosseous vascular malformations from other jaw lesions can be challenging. In the present case, magnetic resonance imaging and three-dimensional computed tomographic angiography (CTA) was used for diagnosis, and the lesion was treated wih surgical excision. Diverse characteristics such as the "honeycomb" and "sunburst" radiographic appearances and the absence of major peripheral feeder vessels in the CTA were noted. Intraosseous vascular malformations have a varied radiographic appearance, and the nomenclature of these lesions is equally diverse, with several overlapping terms. Pathologists do not generally differentiate among intraosseous vascular lesions on the basis of histopathology, although these lesions may present with contrasting immunohistochemical and clinical behaviors requiring varied treatment strategies. This case report highlights the need for multiple imaging modalities to differentiate among vascular lesions, as well as to better understand the behaviors of these unique lesions.

Acute Ischemic Stroke Involving Both Anterior and Posterior Circulation Treated by Endovascular Revascularization for Acute Basilar Artery Occlusion via Persistent Primitive Trigeminal Artery

  • Imahori, Taichiro;Fujita, Atsushi;Hosoda, Kohkichi;Kohmura, Eiji
    • Journal of Korean Neurosurgical Society
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    • 제59권4호
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    • pp.400-404
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    • 2016
  • We report a case of acute ischemic stroke involving both the anterior and posterior circulation associated with a persistent primitive trigeminal artery (PPTA), treated by endovascular revascularization for acute basilar artery (BA) occlusion via the PPTA. An otherwise healthy 67-year-old man experienced sudden loss of consciousness and quadriplegia. Magnetic resonance imaging showed an extensive acute infarction in the right cerebral hemisphere, and magnetic resonance angiography showed occlusion of the right middle cerebral artery (MCA) and BA. Because the volume of infarction in the territory of the right MCA was extensive, we judged the use of intravenous tissue plasminogen activator to be contraindicated. Cerebral angiography revealed hypoplasia of both vertebral arteries and the presence of a PPTA from the right internal carotid artery. A microcatheter was introduced into the BA via the PPTA and revascularization was successfully performed using a Merci Retriever with adjuvant low-dose intraarterial urokinase. After treatment, his consciousness level and right motor weakness improved. Although persistent carotid-vertebrobasilar anastomoses such as a PPTA are relatively rare vascular anomalies, if the persistent primitive artery is present, it can be an access route for mechanical thrombectomy for acute ischemic stroke.

족저 내측부의 동정맥 기형: 증례 보고 (Arteriovenous Malformation on the Medial Plantar Area of the Foot: A Case Report)

  • 하대호;권정남;김유미;이준형
    • 대한족부족관절학회지
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    • 제20권4호
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    • pp.187-191
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    • 2016
  • Arteriovenous malformation (A-V malformation) is defined as an abnormal connection between arteries and veins that lead to A-V shunting with an intervening network of vessels. A-V malformation is a rare condition, and spontaneous regression is also rare. A-V malformation becomes symptomatic when the surrounding tissue and osseous structures are negatively affected. A-V malformation has a high recurrence rate and is relatively hard to treat. In this case, a huge mass with pulsatile and bruit on the medial plantar area were observed. With the diagnosis of A-V malformation in accordance with the results from ultrasonography, magnetic resonance imaging and computed tomography angiography, and mass excision with feeding vessel ligation through plantar midfoot approach was completed successfully.

혈액투석 환자에서 발생한 중심 정맥 협착의 혈관성형술 후 호전된 대뇌 정맥 고혈압: 증례 보고 (Resolved Cerebral Venous Hypertension after Angioplasty of Central Venous Stenosis in a Hemodialysis Patient: A Case Report)

  • 강희민;박성태
    • 대한영상의학회지
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    • 제83권1호
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    • pp.206-211
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    • 2022
  • 혈액투석 환자에서 중심정맥 협착은 비교적 흔한 합병증이다. 하지만 중심정맥 협착으로 인해 대뇌 정맥 고혈압과 이로 인한 신경학적 증상이 발생하는 것은 비교적 드물다. 중심정맥협착으로 인해 발생한 좌측 내경정맥으로부터의 역행성 혈류로 대뇌 정맥 고혈압이 발생한 63세 남성의 증례를 보고하고자 한다. 환자는 중심정맥 협착에 대한 치료를 받은 후 증상 및 치료 전 자기공명영상에서 역행성 혈류를 의미하는 time-of-flight 신호가 소실되었다.

De Novo Vertebral Artery Dissecting Aneurysm after Parent Artery Occlusion of the Contralateral Vertebral Artery

  • Yuichiro Tsuji; Sho Murase; Yuzo Kuroda; Masahiko Wanibuchi
    • Journal of Korean Neurosurgical Society
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    • 제67권1호
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    • pp.115-121
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    • 2024
  • After treatment of unilateral vertebral artery dissecting aneurysm (VADA), de novo VADA rarely occurs on the contralateral side. In this article, we report a case of subarachnoid hemorrhage (SAH) due to de novo VADA in the contralateral vertebral artery (VA) 3 years after parent artery occlusion of unilateral VADA, with a review of the literature. A 47-year-old woman was admitted to our hospital complaining of headache and impaired consciousness. Head computed tomography showed SAH, and three-dimensional computed tomography angiography showed a fusiform aneurysm in the left VA. We performed an emergency parent artery occlusion. Three years and 3 months after the initial treatment, the patient presented to our hospital with complaints of headache and neck pain. Magnetic resonance imaging revealed SAH, and magnetic resonance angiography revealed de novo VADA in the right VA. We performed a stent-assisted coil embolization. The patient had a good postoperative course and was discharged with a modified Rankin scale score of 0. Long-term follow-up is necessary in patients with VADA because contralateral de novo VADA can develop even several years after the initial treatment.