• Progress in Medical Physics
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• v.30 no.4
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• pp.75-88
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• 2019

Diagnostic reference level (DRL) is employed to optimize the radiation doses of patients. The objective of this study is to review the DRLs for interventional procedures in Korea and abroad. Literature review was performed to investigate radiation dose index and measurement methodology commonly used in DRL determination. Dose area product (DAP) and fluoroscopy time within each major procedure category were systematically abstracted and analyzed. A wide variation was found in the radiation dose. The DAP values and fluoroscopy times ranged 0.01-3,081 Gy·㎠ and 2-16,878 seconds for all the interventional procedures, 8.5-1,679 Gy·㎠ and 32-5,775 seconds for the transcatheter arterial chemoembolization (TACE), and 0.1-686 Gy·㎠ and 16-6,636 seconds for the transfemoral cerebral angiography (TFCA), respectively. The DRL values of the DAP and fluoroscopy time were 238 Gy·㎠ and 1,224 seconds for the TACE and 189 Gy·㎠ and 686 seconds for the TFCA, respectively. Generally, the DRLs of Korea were lower than those of other developed countries, except for the percutaneous transluminal angioplasty with stent in arteries of the lower extremity (LE PTA and stent), aneurysm coil embolization, and Hickman insertion procedures. The wide variation in the radiation doses of the different procedures suggests that more attention must be paid to reduce unnecessary radiation exposure from medical imaging. Furthermore, periodic nationwide survey of medical radiation exposures is necessary to optimize the patient dose for radiation protection, which will ultimately contribute to patient dose reduction and radiological safety.

• Journal of Korean Neurosurgical Society
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• v.59 no.4
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• pp.379-384
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• 2016

Objective : Mechanical thrombectomy (MT) for acute intracranial internal carotid artery (ICA) occlusion is often complicated by difficult revascularization and non-involved territory embolization possibly related with larger clot-burden. This study aims to evaluate the efficacy of proximal aspiration thrombectomy (PAT) using a balloon-tipped guide catheter for clot-burden reduction in such cases with period-to-period analysis (period 1 : standard MT without PAT; period 2 : PAT first, then standard MT for the remaining occlusion). Methods : Eighty-six patients who underwent MT for acute intracranial ICA occlusion were included in this analysis from the prospectively maintained stroke registry (33 patients in period 1 and 53 in period 2). In period 2, 'responder' was defined as a case where some amount of clot was retrieved by PAT and the following angiography showed partial or full recanalization. Results : Fifteen of fifty-three patients in period 2 (28.3%) were 'responders' to PAT. There was a significantly higher incidence of atrial fibrillation in the 'responder' subgroup. Period 2 showed a significantly shorter puncture-to-reperfusion time (94.5 minutes vs. 56.0 minutes; p=0.002), a significantly higher Thrombolysis in Cerebral Infarction of 2b-3 reperfusion (45.5% vs. 73.6%; p=0.009), but only a trend for better 3-month favorable outcome (mRS 0-2; 36.4% vs. 54.7%; p=0.097). There was no increase in the incidence of procedure-related complications or intracranial hemorrhage in period 2. Conclusion : A strategy of PAT before standard MT may result in shorter puncture-to-reperfusion time and better angiographic outcome than a strategy of standard MT for acute intracranial ICA occlusion.

• Journal of Korean Neurosurgical Society
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• v.45 no.6
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• pp.360-368
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• 2009

Objective : The objectives of this study were to analyze the recanalization rates and outcomes of multimodal therapy that consisted of sequential intravenous (IV)/intra-arterial (IA) thrombolysis, mechanical thrombolysis including mechanical clot disruption using microcatheters and microwires, balloon angioplasty, and stenting for acute ischemic stroke, and to evaluate the prognostic factors related to the outcome. Methods : Fifty patients who were admitted to the hospital within 8 hours from ischemic symptom onset were retrospectively analyzed. Initial IV thrombolysis and subsequent cerebral angiography were performed in all patients. If successful recanalization was not achieved by IV thrombolysis, additional IA thrombolysis with mechanical thrombolysis, including balloon angioplasty and stenting, were performed. The outcomes were assessed by the National Institute of Health Stroke Scale (NIHSS) change and modified Rankin scale (mRS) and prognostic factors were analyzed. Results : Successful recanalization was achieved in 42 (84%) of 50 patients, which consisted of 8 patients after IV thrombolysis, 19 patients after IA thrombolysis with mechanical clot disruption, and 15 patients after balloon angioplasty or stenting. Symptomatic hemorrhage occurred in 4 (8%) patients. Good outcomes were achieved in 76% and 70% of patients upon discharge, and 93% and 84% of patients after 3 months according to the NIHSS change and mRS. The initial clinical status, recanalization achievement, and presence of symptomatic hemorrhage were statistically related to the outcomes. Conclusion : Multimodal therapy may be an effective and safe treatment modality for acute ischemic stroke. Balloon angioplasty and stenting is effective for acute thrombolysis, and produce higher recanalization rates with better outcomes.

• Journal of Korean Neurosurgical Society
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• v.64 no.1
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• pp.30-38
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• 2021

Objective : The Solitaire Platinum 4×40 mm stent retriever contains radiopaque markers with a long length. We evaluated the effect of Solitaire Platinum 4×40 mm stent retriever in Solumbra technique thrombectomy, and compared it with shorter Solitaire stent retrievers. Methods : A total of 70 patients who underwent Solumbra technique thrombectomy with equal diameter (4 mm) and different length (40 vs. 20 mm) Solitaire stent retrievers were divided into two groups : the Solitaire Platinum 4×40 mm stent (4×40) group and the Solitaire FR 4×20 mm stent or Solitaire Platinum 4×20 mm stent (4×20) group. The clinical outcomes, Thrombolysis in Cerebral Infarction score, the first pass reperfusion status, and complications were evaluated and compared between the two groups. Multivariate analysis was performed to evaluate the predictive factors for reperfusion and complete reperfusion from the first pass. Results : Higher first-pass reperfusion and complete reperfusion were achieved in the 4×40 group (68.0% and 48.0%) than in the 4×20 group (46.7% and 33.3%; p=0.004 and 0.007, respectively). In multivariate analysis, radiopaque device and longer stent retriever were correlated with first-pass reperfusion (p=0.014 and 0.008, respectively) and first-pass complete reperfusion (p=0.022 and 0.012, respectively). Conclusion : Our study demonstrated the usefulness of the Solitaire Platinum 4×40 mm stent retriever, which led to higher first-pass reperfusion and complete reperfusion rates than the Solitaire FR 4×20 mm stent or the Solitaire Platinum 4×20 mm stent, especially in Solumbra technique thrombectomy.

• Journal of Korean Neurosurgical Society
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• v.66 no.4
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• pp.418-425
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• 2023

Objective : Deciphering the anatomy of posterior communicating artery (PCoA) aneurysms in relation to surrounding structures is essential to determine adjuvant surgical procedures. However, it is difficult to predict surgical structures through preoperative imaging studies. We aimed to present anatomical structures using preoperative high-resolution three-dimensional proton density-weighted turbo spin-echo magnetic resonance (PDMR) imaging with simple classification. Methods : From January 2020 to April 2022, 30 patients underwent PDMR before microsurgical clipping for unruptured PCoA aneurysms in a single tertiary institute. We retrospectively reviewed the radiographic images and operative data of these patients. The structural relationship described by PDMR and intraoperative findings were compared. Subsequently, we classified aneurysms into two groups and analyzed the rate of adjuvant surgical procedures and contact with the surrounding structures. Results : Correlations between preoperative PDMR predictions and actual intraoperative findings for PCoA aneurysm contact to the oculomotor nerve, temporal uncus, and anterior petroclinoid fold (APCF) reported a diagnostic accuracy of 0.90, 0.87, and 0.90, respectively. In 12 patients (40.0%), an aneurysm dome was located on the plane of the oculomotor triangle and was classified as the infratentorial type. Compared to the supratentorial type PCoA aneurysm, adjuvant procedures were required more frequently (66.7% vs. 22.2%, p=0.024) for infratentorial type PCoA aneurysm clipping. Conclusion : Preoperative PCoA aneurysm categorization using PDMR can be helpful for predicting surgical complexity and planning of microsurgical clipping.

• Journal of the Korean Society of Radiology
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• v.84 no.5
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• pp.1152-1157
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• 2023

Common carotid artery occlusion (CCAO) is a very rare disorder that has rarely been studied. CCAO causes several neurological symptoms but can sometimes be asymptomatic due to the development of various anastomoses. Herein, we report the case of a 70-year-old male patient diagnosed with asymptomatic CCAO due to anastomotic flow. The patient underwent transfemoral cerebral angiography (TFCA) and was found to have CCAO with two collateral pathways, including an occipital artery-vertebral artery anastomosis. We emphasize the importance of TFCA when CCAO is suspected and review the types and anastomotic pathways of CCAO.

• Investigative Magnetic Resonance Imaging
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• v.3 no.2
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• pp.173-178
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• 1999

Purpose : To evaluate the usefulness of functional MRI (fMRI) of visual cortex in patients with ischemic infarction in the occipital lobe. Materials and Methods : Four patients with the symptoms and signs of visual cortical ischemia were included. Functional MRI was performed by 2D-FLASH technique with the parameter of 90/56msec TR/TE, $40^{\circ}$ flip angle, $240{\times}240{\;}FOV,{\;}64{\times}128$ matrix number, 8.32 seconds acquisition time, 8mm slice thickness. An axial slice including both visual cortices was selected and alternative activation and resting of the visual cortex was performed using red color photostimulator. all patients undertook visual field test, and vascular abnormality was examined by MRA (n=4) and DSA (n=2). fMRI results were compared with the results of a visual field test, conventional MRI and cerebral angiography. Results : On fMRI, decreased activity of the visual cortex was found in the occipital lobe corresponding to stenosis of the posterior cerebral artery or its branch noted on angiogram. However, 2 of 4 patients showed no abnormal findings on conventional MRI. Visual field defect was noted in 3 patients, one and of whom showed no abnormality on conventional MRI and diffusion-weighted image, but revealed decreased activity in the corresponding visual cortex on fMRI. Conclusion : fMRI may be a sensitive method for detection of the status of decreased blood flow or vascular reserve which other methods can not.

• Journal of Chest Surgery
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• v.30 no.2
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• pp.172-178
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• 1997

We present a etrospective analysis of arterial embolectomies performed at the Inje University Seoul Paik Hospital. During the period of March 1987 Feburary 1996 twenty-six patients underwent embolectomies, eighteen patients were male and eight patients were female, mean age of patients was 56.8 years. Rest pain was the chief complaint in 24 patients, the remaining two patients complained of long term history of claudication after recovery of acute symtoms. But only 10 patients had sensBrylmotor symtoms. Heart was the most common source of embolization and frequent predisposing factor of embolism was ischemic heart disease in 8 cases and valvular heart disease in 11 cases. The sites of embolization were upper extremities artery in 6 cases, saddle embolism in 2 cases, lower extremities artery in 18 cases and the most common site of embolism was femoral artery in 1 1 cases. Preoperative angiography was taken in the diagnosis and planning of the embolectomy in 1) patients while in the other patient p eoperative angiography was not taken. Only two cases were operated within the golden period of 6 hours and other cases were operated in more than 6 hours after embolization. In all patients, the Fogarty embolectomy catheter was used without bypass surgery via bachial ateriotomy in the embolism of upper extremities artery, bilateral groin approaches in the saddle embolism and transfemoral approach in the embolism of lower extremities artery. However 3 patients were re-operated via transpopliteal approach in the distal poplitiotibial embolism. Eighteen patients received perioperative anticoagulation therapy by heparin or fraxiparine and wafarin was used in 17 patients at the time of discharge and the indication of anticogulation was patients of valvular heat disease andfor atrial fibrillation, peripheral artery atherosclerosis and recurrent embolism. Postoperative results of the embolectomy were as follows: fouteen pateints had excellent results, five cases had symtom improvement after re-operation, B. K. amputation in 1 case who had severe atherosclerosis of lower extremities, recurrent embolism in 1 case and death in 2 cases the cause of death were acute renal failure and cerebral artery embolism, respectively. The complications of the embolectomy were reperfusion syndrome, pseudoaneurysm and intimal dissection in one case each. Conclusively the problems of embolism is delayed diagnosis and increasing number of old aged patient who had suffered from ischemic heart diease. Preoperative angiography was not always needed for embol ectomy. Selective anticoagulation therapy can decrease incidence of re-embolism. In the distal poplitiotibial embolism, embolectomy of tibial artery was difficult.

• The Journal of the Society of Stroke on Korean Medicine
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• v.7 no.1
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• pp.11-16
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• 2006

Objectives : Transcranial Doppler (TCD) has been reported to be established as useful in detecting spasm after subarachnoid hemorrhage and to be probably useful in diagnosing stenosis or occlusion in intracranial arteries. In the detection of intracranial stenosis using TCD there have been reported some kinds of diagnostic criteria. This study was aimed to evaluate the accordance between TCD and magnetic resonance angiography (MRA) in detection of intracranial stenosis and to find out more accurate criteria for intracranial stenosis using TCD. Methods : Seventy-six stroke patients were evaluated by TCD and MRA. TCD criteria for middle cerebral artery (MCA) stenosis were used by 3 methods; ≥ 80cm/sec of mean velocity(Vm), ≥ 140 cm/sec of systolic velocity(Vs), and both. For stenosis of vertebral(VA) and basilar arteries(BA), the TCD criteria followed by 2 methods; ≥ 70 cm/sec of Vm and ≥ 100 cm/sec of Vs. The stenosis of intracranial artery in MRA followed by the interpretation of specialist in the department of radiology. The sensitivity, specificity, positive predictive value, negative predictive value, diagnostic accuracy and kappa agreement were calculated in each criteria of TCD compared with the result of MRA. Results : The sensitivity, specificity, positive predictive value, negative predictive value, diagnostic accuracy and kappa agreement using ≥ 80cm/sec of Vm for MCA stenosis were 55.6%, 81%, 34.5%, 91.0%, 77.1%, and 0.293, respectively. Using 140 cm/sec of Vs, those were 44.4%, 92.0%, 50.5%, 90.2%, 84.7%, 0.380, and using both criteria those were 44.4%, 95.0%, 61.5%, 90.5%, 87.3%, 0.445, respectively. Those using ≥ 70 cm/sec of Vm for VA and BA stenosis were 71.4%, 93.7%, 26.3%, 99.0%, 93.0%, 0.186 and using ≥ 100 cm/sec of Vs those were 71.4%, 97.3%, 45.5%, 99.1%, 96.5%, 0.539, respectively. Conclusion : These results suggested that for the diagnosis of MCA stenosis using TCD we should use the criteria of both ≥ 80cm/sec of Vm and 140 cm/sec of Vs, and for the VA and BA stenosis we adapt the criteria of ≥ 70 cm/sec of Vm.

• Annals of Clinical Neurophysiology
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• v.10 no.2
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• pp.104-108
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• 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.