• Korean Journal of Radiology
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• v.2 no.3
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• pp.151-158
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• 2001

Objective: To determine the ability of MR imaging to detect the pathological changes occurring in radiofrequency (RF) thermal lesions and to assess its accuracy in revealing the extent of tissue necrosis. Materials and Methods: Using an RF electrode, thermal lesions were created in the livers of 18 rabbits. The procedure involved three phases. In the acute phase, six animals were killed the day after performing thermal ablation with RF energy, and two on day 3. In the subacute and chronic phases, eight rabbits underwent percutaneous hepatic RF ablation. After performing MR imaging, two animals were sacrificed at 1, 2, 4, and 7 weeks after the procedure, and MRpathologic correlation was performed. Results: In the acute phase, the thermal ablation lesions appeared at gross examination as well-circumscribed, necrotic areas, representing early change in the coagulative necrosis seen at microscopic examination. They were hypointense on T2-weighted images, and hyperintense on T1-weighted images. Gadolinium-enhanced MR imaging showed that a thin hyperemic rim surrounded the central coagulative necrosis. In the subacute phase, ablated lesions also showed extensive coagulative necrosis and marked inflammation at microscopic examination. Beyond two weeks, the lesions showed gradual resorption of the necrotic area, with a peripheral fibrovascular rim. The size of lesions measured by MR imaging correlated well with the findings at gross pathologic examination. Conclusion: MR imaging effectively demonstrates the histopathological tissue change occurring after thermal ablation, and accurately determines the extent of the target area.

• Journal of the Korean Society of Radiology
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• v.84 no.5
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• pp.1185-1190
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• 2023

Pseudoaneurysms are among the most serious complications of percutaneous balloon angioplasty. Although pseudoaneurysm rupture rarely happens, when it does, the result can be fatal; thus, early detection and management are crucial. In this report, we disclose the case of a 34-year-old male with end-stage renal disease who presented with a huge symptomatic pseudoaneurysm of the left popliteal artery, following percutaneous balloon angioplasty three months prior. The pseudoaneurysm was successfully excluded using interventional treatment. The patient recovered well, and the follow-up was uneventful, with excellent patency of the covered stent.

• Journal of the Korean Society of Radiology
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• v.11 no.7
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• pp.579-587
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• 2017

Although interventional procedures use very low tube currents, there is a high risk of exposure to radiation as well as the operator due to long-term radiation exposure. The purpose of this study is to investigate the effects of radiation dose on the quality of the operator by measuring the dose received by the operator in the interventional procedure of the cerebral vascular system and finding the shielding material and shielding method which can effectively shield the exposure from the medical radiation. And to find a way to minimize it to the extent that it does not. As a result, when the newly designed shielding system with Nano Tungsten material was used, it was confirmed that the mean dose was reduced by 7.95% on average by the operator. Also, the PSNR results were measured to be 38.44 dB when using the designed shielding material, and it was confirmed that Nano Tungsten does not affect the image quality. In conclusion, the Nano Tungsten shielding material proved to be capable of significantly reducing the operator radiation dose, without affecting the image quality. The use of the above materials is expected to solve the problems related to the harmfulness and economical efficiency of the human body and the environment, which have recently become an issue of shielding materials.

• Journal of the Korean Society of Radiology
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• v.8 no.1
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• pp.1-10
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• 2014

The bi-plane cerebrovascular angiography radiation is done the radiation exposure at the forward and lateral direction as opposed to the one of the source. So, the exposure dose of radiation workers increases further. Therefore, the medical diagnostic radiation workers as well as patients is interested to ways to reduce the dose. The exposure dose of cerebral angiography and interventional radiology must be considered the primary radiation of X-ray tube directly, scattered primary radiation between lateral tube and lateral detector and relatively small secondary scatter radiation in the walls of room. The aim of study is that the exposure dose of primary and scatter radiation reduce as much as possible to install protection device of lateral protection than common shielding of table and ceiling. As a result, the dose of fluoroscopy was reduced approximately 3.64 times the gonads, thyroid approximately 3.13 times, 4.42 times around eyes. And the dose of DSA was reduced approximately 4.98 times the gonads, thyroid approximately 3.00 times, 1.67 times around eyes. Consequently, medical practitioners can be helpful for radiation dose-exposure for the lateral protection of bi-plane cerebrovascular angiography more than the common shield method in cerebrovascular angiography and interventional radiological procedures.

• Korean Journal of Radiology
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• v.22 no.12
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• pp.1964-1973
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• 2021

Objective: To investigate the diagnostic performance of CT fractional flow reserve (CT-FFR) for myocardial bridging-related ischemia using dynamic CT myocardial perfusion imaging (CT-MPI) as a reference standard. Materials and Methods: Dynamic CT-MPI and coronary CT angiography (CCTA) data obtained from 498 symptomatic patients were retrospectively reviewed. Seventy-five patients (mean age ± standard deviation, 62.7 ± 13.2 years; 48 males) who showed myocardial bridging in the left anterior descending artery without concomitant obstructive stenosis on the imaging were included. The change in CT-FFR across myocardial bridging (ΔCT-FFR, defined as the difference in CT-FFR values between the proximal and distal ends of the myocardial bridging) in different cardiac phases, as well as other anatomical parameters, were measured to evaluate their performance for diagnosing myocardial bridging-related myocardial ischemia using dynamic CT-MPI as the reference standard (myocardial blood flow < 100 mL/100 mL/min or myocardial blood flow ratio ≤ 0.8). Results: ΔCT-FFR_systolic (ΔCT-FFR calculated in the best systolic phase) was higher in patients with vs. without myocardial bridging-related myocardial ischemia (median [interquartile range], 0.12 [0.08-0.17] vs. 0.04 [0.01-0.07], p < 0.001), while CT-FFR_systolic (CT-FFR distal to the myocardial bridging calculated in the best systolic phase) was lower (0.85 [0.81-0.89] vs. 0.91 [0.88-0.96], p = 0.043). In contrast, ΔCT-FFR_diastolic (ΔCT-FFR calculated in the best diastolic phase) and CT-FFR_diastolic (CT-FFR distal to the myocardial bridging calculated in the best diastolic phase) did not differ significantly. Receiver operating characteristic curve analysis showed that ΔCT-FFR_systolic had largest area under the curve (0.822; 95% confidence interval, 0.717-0.901) for identifying myocardial bridging-related ischemia. ΔCT-FFR_systolic had the highest sensitivity (91.7%) and negative predictive value (NPV) (97.8%). ΔCT-FFR_diastolic had the highest specificity (85.7%) for diagnosing myocardial bridging-related ischemia. The positive predictive values of all CT-related parameters were low. Conclusion: ΔCT-FFR_systolic reliably excluded myocardial bridging-related ischemia with high sensitivity and NPV. Myocardial bridging showing positive CT-FFR results requires further evaluation.

• Journal of the Korean Society of Radiology
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• v.84 no.4
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• pp.809-823
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• 2023

Trauma is an injury to the body that involves multiple anatomical and pathophysiological changes caused by forces acting from outside the body. The number of patients with trauma is increasing as our society becomes more sophisticated. The importance and demand of traumatology are growing due to the development and spread of treatment and diagnostic technologies. In particular, damage to the large blood vessels of the chest can be life-threatening, and the sequelae are often severe; therefore, diagnostic and therapeutic methods are becoming increasingly important. Trauma to nonaortic vessels of the thorax and aorta results in varying degrees of physical damage depending on the mechanism of the accident and anatomical damage involved. The main damage is hemorrhage from non-aortic vessels of the thorax and aorta, accompanied by hemodynamic instability and coagulation disorders, which can be life-threatening. Immediate diagnosis and rapid therapeutic access can often improve the prognosis. The treatment of trauma can be surgical or interventional, depending on the patient's condition. Among them, interventional procedures are increasingly gaining popularity owing to their convenience, rapidity, and high therapeutic effectiveness, with increasing use in more trauma centers worldwide. Typical interventional procedures for patients with thoracic trauma include embolization for non-aortic injuries and thoracic endovascular aortic repair for aortic injuries. These procedures have many advantages over surgical treatments, such as fewer internal or surgical side effects, and can be performed more quickly than surgical procedures, contributing to improved outcomes for patients with trauma.

• Journal of The Korean Radiological Technologist Association
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• v.30 no.1
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• pp.148-158
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• 2004

Purpose : Most Patients experienced severe tension and/or anxiety during invasive procedures at angiography room. To ease patients' emotion and to improve their tolerance to the procedure, we applied music therapy. Material and Methods : Between March 1 a

• Journal of the Korean Society of Radiology
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• v.5 no.5
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• pp.303-308
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• 2011

Background/Aims : The increasing use of diagnostic and therapeutic interventional radiology calls for greater consideration of radiation exposure risk to radiologist and radiological technician, and emphasizes the proper system of radiation protection. This study was designed to assess the effect of a protective grass shield. Methods : A protective grass was following data depth, 0.8 cm; width, 100 cm; length, 100 cm, lead equivalent, 1.6 mmPb. The protective shield was located between the patient and the radiologist. Thirty patients (13 male and 17 female) undergoing interventional radiology between September 2010 and December 2010 were selected for this study. The dose of radiation exposure was recorded with or without the protective grass shield at the level of the head, chest, and pelvis. The measurement was made at 50 cm and 150 cm from the radiation source. Results : The mean patient age was 69 years. The mean patient height and weight was $159.7{\pm}6.7$ cm and $60.3{\pm}5.9$ kg, respectively. The mean body mass index (BMI) was $20.5{\pm}3.0$ kg/m2. radiologists received $1530.2{\pm}550.0$ mR/hr without the protective lead shield. At the same distance, radiation exposure was significantly reduced to $50.3{\pm}85.2$ mR/hr with the protective lead shield (p-value<0.0001). The radiation exposure to radiologist and radiological technician was significantly reduced by the use of a protective lead shield (p value <0.0001). The amount of radiation exposure during interventional radiology was related to the patient' BMI (r=0.749, p=0.001). Conclusions : This protective shield grass is effective in protecting radiologist and radiological technician from radiation exposure.

• Journal of the Korean Society of Radiology
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• v.6 no.1
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• pp.11-17
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• 2012

The purpose of this study is to measure and evaluate radiation dose on patients in interventional radiological(IVR) procedures classified by each procedure, and aid as data for safety management. Fluroscopy time(F-time), dose area product(DAP) and number of acquired images from each kind of procedure was checked. Non-vascular procedures showed low value, and vascular procedure showed high value in all procedures except in IVC filter. F-time was longest in EVAR, which showed also the highest DAP value of all procedures. DAP-rate showed high value in TACE. By this result, we attempt to establish standard guideline of radiation dose on patients in IVR procedure.

• Korean Journal of Radiology
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• v.1 no.3
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• pp.121-126
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• 2000

Objective: To evaluate the therapeutic efficacy of a new liquid embolic material, Embol, in embolization of the renal artery. Materials and Methods: Embol is a new embolic material obtained by partial hydrolysis of polyvinyl acetate mixed in absolute ethanol and Iopromide 370 and manufactured by Schering Korea, Kyonggido, Korea. Six patients who underwent embolization of the renal artery using Embol were evaluated. Four were male and two were female and their ages ranged from 11 to 70 (mean, 53) years. Clinical and radiologic diagnoses referred for renal artery embolization were renal cell carcinoma (n = 3), renal angiomyolipoma (n = 2) and pseudoaneurysm of the renal artery (n = 1). After selective renal angiography, Embol was injected through various catheters, either with or without a balloon occlusion catheter. Changes in symptoms and blood chemistry which may have been related to renal artery embolization with Embol were analyzed. Results: The six patients showed immediate total occlusion of their renal vascular lesions. One of the three in whom renal cell carcinoma was embolized with Embol underwent radical nephrectomy, and the specimen thus obtained revealed 40% tumor necrosis. In the two patients with angiomyolipomas, the tumors decreased in size and abdominal pain subsided. Bleeding from pseudoaneurysm of the renal artery was successfully controlled. Four patients showed symptoms of post-embolization syndrome, and one of these also showed increased levels of blood urea nitrogen and creatinine. One patient experienced transient hypertension. Conclusion: Embol is easy to use, its radiopacity is adequate and it is a safe and effective embolic material which provides immediate and total occlusion of renal vascular lesions.