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김여군,박은아,박상준,천기정,이활,정진욱,박재형 대한영상의학회 2014 Korean Journal of Radiology Vol.15 No.2
Herein we report about the adenosine stress perfusion MR imaging findings of a 50-year-old man who exhibited two different perfusion defects resulting from two different mechanisms after a coronary artery bypass surgery. An invasive coronary angiography confirmed that one perfusion defect at the mid-anterior wall resulted from an ischemia due to graft stenosis. However, no stenosis was detected on the graft responsible for the mid-inferior wall showing the other perfusion defect. It was assumed that the perfusion defect at the mid-inferior wall resulted from delayed perfusion owing to the long pathway of the bypass graft. The semiquantitative analysis of corrected signal-time curves supported our speculation, demonstrating that the rest-to-stress ratio index of the maximal slope of the myocardial territory in question was similar to those of normal myocardium, whereas that of myocardium with the stenotic graft showed a typical ischemic pattern. A delayed perfusion during long graft pathway in a post-bypass graft patient can mimick a true perfusion defect on myocardial stress MR imaging. Radiologists should be aware of this knowledge to avoid misinterpretation of graft and myocardial status in post bypass surgery patients.
Epithelioid Hemangioendothelioma of the Femur with Benign Cystic Appearance
김여군,최정아,정진행,오주한,강흥식 대한영상의학회 2011 대한영상의학회지 Vol.65 No.6
An epithelioid hemangioendothelioma is an intermediate grade tumor between hemangioma and angiosarcoma that frequently shows marked enhancement because it is a vascular tumor. Herein, we describe a rare case of a malignant epithelioid hemangioendothelioma of the femur that was mistaken as a benign lesion such as a simple bone cyst or fibrous dysplasia because the tumor had a benign cystic appearance on MRI and its imaging findings showed a histopathologic correlation.
김여군,이준우,김재형,강흥식,박경석 대한영상의학회 2011 대한영상의학회지 Vol.65 No.2
Purpose: To compare the diffusion characteristics of idiopathic acute transverse myelitis (ATM) and acute spinal cord infarction (SCI). Materials and Methods: Diffusion-weighted images (DWI) and an apparent diffusion coefficient (ADC) map were prospectively obtained from patients diagnosed with myelopathy between February 2006 and April 2009. Inclusion criteria included 1) the presence of an intramedullary T2-high signal intensity and 2) a final diagnosis of idiopathic ATM or SCI established by one neurologist. In total, 13 patients (M : F = 8 : 5; mean age, 39.5 years; range, 29-50 years) with idiopathic ATM and seven patients (M : F = 2 : 5; mean age, 58 years; range, 48-75 years) with SCI were included in this study. Two radiologists evaluated the DWIs and ADC map in consensus. The extent of the cord signal change was also evaluated on T2-weighted sagittal images. Results: Among the 16 patients with ATM, 14 patients showed iso-signal on an ADC map, but one case showed restricted diffusion and another showed increased diffusion on the ADC map. Among the seven patients with SCI, five patients showed restricted diffusion. Conclusion: Idiopathic ATM usually does not demonstrate restricted diffusion, which can be a clue to differentiate it from SCI. However, idiopathic ATM with larger segment involvement can show focal diffusion restriction.
김중희,강준원,김규석,최상일,전은주,김여군,김원영,서동우,신종환,이휘재,진광남,안소연,황승식,김광표,정루비,하상욱,최병호,윤창환,서정원,김학령,김주경,장수진,서지선 대한응급의학회 2017 Clinical and Experimental Emergency Medicine Vol.4 No.4
Objective Chest pain is one of the most common complaints in the emergency department (ED). Cardiac computed tomography angiography (CCTA) is a frequently used tool for the early triage of patients with low- to intermediate-risk acute chest pain. We present a study protocol for a multicenter prospective randomized controlled clinical trial testing the hypothesis that a lowdose CCTA protocol using prospective electrocardiogram (ECG)-triggering and limited-scan range can provide sufficient diagnostic safety for early triage of patients with acute chest pain. Methods The trial will include 681 younger adult (aged 20 to 55) patients visiting EDs of three academic hospitals for acute chest pain or equivalent symptoms who require further evaluation to rule out acute coronary syndrome. Participants will be randomly allocated to either low-dose or conventional CCTA protocol at a 2:1 ratio. The low-dose group will undergo CCTA with prospective ECG-triggering and restricted scan range from sub-carina to heart base. The conventional protocol group will undergo CCTA with retrospective ECG-gating covering the entire chest. Patient disposition is determined based on computed tomography findings and clinical progression and all patients are followed for a month. The primary objective is to prove that the chance of experiencing any hard event within 30 days after a negative low-dose CCTA is less than 1%. The secondary objectives are comparisons of the amount of radiation exposure, ED length of stay and overall cost. Results and Conclusion Our low-dose protocol is readily applicable to current multi-detector computed tomography devices. If this study proves its safety and efficacy, dose-reduction without purchasing of expensive newer devices would be possible.
이은채,김여군,전은주,최상일 대한영상의학회 2016 대한영상의학회지 Vol.74 No.5
Purpose: To assess the performance of model-based iterative reconstruction (MBIR) technique for evaluation of coronary artery stents on coronary CT angiography (CCTA). Materials and Methods: Twenty-two patients with coronary stent implantation who underwent CCTA were retrospectively enrolled for comparison of image quality between filtered back projection (FBP), adaptive statistical iterative reconstruction (ASIR) and MBIR. In each data set, image noise was measured as the standard deviation of the measured attenuation units within circular regions of interest in the ascending aorta (AA) and left main coronary artery (LM). To objectively assess the noise and blooming artifacts in coronary stent, we additionally measured the standard deviation of the measured attenuation and intra-luminal stent diameters of total 35 stents with dedicated software. Results: All image noise measured in the AA (all p < 0.001), LM (p < 0.001, p = 0.001) and coronary stent (all p < 0.001) were significantly lower with MBIR in comparison to those with FBP or ASIR. Intraluminal stent diameter was significantly higher with MBIR, as compared with ASIR or FBP (p < 0.001, p = 0.001). Conclusion: MBIR can reduce image noise and blooming artifact from the stent, leading to better in-stent assessment in patients with coronary artery stent.
유진영,전은주,김여군,최상일,최동주 대한자기공명의과학회 2014 Investigative Magnetic Resonance Imaging Vol.18 No.1
Purpose : To evaluate the prevalence and pattern of perfusion defect (PD) on first-pass stress perfusion MR imaging inrelation with the degree of left ventricular hypertrophy (LVH) and late gadolinium-enhancement (LGE) in patients with apicalhypertrophic cardiomyopathy (APH). Materials and Methods: Cardiac MR imaging with first-pass stress perfusion, cine, and LGE sequence was performed in26 patients with APH from January 2008 to December 2012. We analyzed a total of 416 segments for LV wall thicknesson end-diastolic phase of cine images, and evaluated the number of hypertrophied segment and number of consecutivehypertrophied segment (NCH). We assessed the presence or absence of PD and LGE from all patients. If there was PD, wesubdivided the pattern into sporadic (sporadic-PD) or ring (ring-PD). Using univariate logistic method, we obtained theindependent predictor for presence of overall PD and ring-PD. Results: PD on stress perfusion MRI was observed in 20 patients (76.9%), 12 of them (60%) showed ring-PD. Maximal LVwall thickness and number of hypertrophied segment were independent predictors for overall PD (all, p < 0.05). NCH withmore than 3 segments was an additional independent factor for ring-PD. However, LGE was not statistically related withPD in patients with APH. Conclusion: About three quarters of the patients with APH showed PD, most of them represented as ring-PD. LVH degreeor distribution was related with pattern of PD, however, LGE was not related with PD. Therefore, the clinical significanceof PD in the patients with APH seems to be different from those with non-APH, and further comparison study betweenthe two groups should be carried out.
이재환,전은주,김여군,유진영,최상일,최동주 대한영상의학회 2015 대한영상의학회지 Vol.73 No.1
Purpose: To evaluate the prevalence of coexistent coronary artery disease (CAD) or myocardial bridging (MB) in patients with hypertrophic cardiomyopathy (HCM) using coronary CT angiography (CCTA) and assess the role of CCTA. Materials and Methods: The prevalence of obstructive CAD (> 50% luminal reduction) and MB (partial and full encasement) were assessed in 150 patients with HCM diagnosed by clinical findings, electrocardiography, and echocardiography of 19588 consecutive patients who underwent CCTA for suspected CAD. Results: The overall feasibility of coronary artery visualization was 98.9% with CCTA. In patients with HCM, the prevalence of obstructive CAD and MB (14.7% partial and 28.0% full encasement) were 23.3% and 42.7%, respectively. Age, hypertension, family history of premature CAD, Framingham risk score and severe chest pain were associated with CAD, whereas male gender and septal type were associated with MB (all p < 0.05). In comparison to invasive coronary angiography (n = 37), the diagnostic accuracy of CCTA for the detection of CAD and full encasement MB was 89.2% and 86.5%, respectively. Conclusion: One-quarter of patients with HCM had coexistent obstructive CAD or full encasement MB. CCTA can be a feasible and accurate noninvasive imaging modality for the detection of CAD and MB in patients with HCM.
김민정,윤연이,박진주,김여군,전은주,최상일,조구영 대한심장학회 2017 Korean Circulation Journal Vol.47 No.3
Coronary magnetic resonance angiography (CMRA) allows a noninvasive assessment of the coronary anatomy without exposing the patients to radiation. It is also superior to coronary computed tomography angiography (CCTA) for the evaluation of luminal narrowing in heavily calcified coronary segments. We report a case with triple-vessel disease, but it could not be accurately assessed by CCTA because of calcification and lack of a significant perfusion defect or myocardial scarring on cardiac magnetic resonance imaging (MRI). However, whole-heart CMRA performed as part of the cardiac MRI protocol demonstrated significant triple-vessel disease with left main involvement, confirmed by subsequent invasive angiography with a fractional flow reserve measurement.
문재훈,김지훈,이은경,이규은,공성혜,김여군,정우진,이창윤,유노을,황보율,송영신,김민주,조선욱,김수진,정은재,최준영,유창환,이유진,하정훈,정유성,류준선,황윤지,Sue K. Park,성호경,이가희,박도준,박영주 대한내분비학회 2018 Endocrinology and metabolism Vol.33 No.2
Background: The ongoing Multicenter Prospective Cohort Study of Active Surveillance on Papillary Thyroid Microcarcinoma (MAeSTro) aims to observe the natural course of papillary thyroid microcarcinoma (PTMC), develop a protocol for active surveillance (AS), and compare the long-term prognosis, quality of life, and medical costs between the AS and immediate surgery groups. Methods: This multicenter prospective cohort study of PTMC started in June 2016. The inclusion criteria were suspicious of malignancy or malignancy based on fine needle aspiration or core needle biopsy, age of ≥18 years, and a maximum diameter of ≤1 cm. If there was no major organ involvement, no lymph node/distant metastasis, and no variants with poor prognosis, the patients were explained of the pros and cons of immediate surgery and AS before selecting AS or immediate surgery. Follow-up visits (physical examination, ultrasonography, thyroid function, and questionnaires) are scheduled every 6 months during the first 2 years, and then every 1 year thereafter. Progression was defined as a maximum diameter increase of ≥3, ≥2 mm in two dimensions, suspected organ involvement, or lymph node/distant metastasis. Results: Among 439 enrolled patients, 290 patients (66.1%) chose AS and 149 patients (33.9%) chose immediate surgery. The median follow-up was 6.7 months (range, 0.2 to 11.9). The immediate surgery group had a larger maximum tumor diameter, compared to the AS group (7.1±1.9 mm vs. 6.6±2.0 mm, respectively; P=0.014). Conclusion: The results will be useful for developing an appropriate PTMC treatment policy based on its natural course and risk factors for progression.