• 대한의용생체공학회:의공학회지
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• 제38권6호
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• pp.295-301
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• 2017

In this study, We subtracted the calcification blooming artifact from MDCT images of coronary atherosclerosis patients and verified their accuracy and usefulness. We performed coronary artery calcification stenosis phantom and a program to subtract calcification blooming artifact by applying 8 different image segmentation method (Otsu, Sobel, Prewitt, Canny, DoG, Region Growing, Gaussian+K-mean clustering, Otsu+DoG). As a result, In the coronary artery calcification stenosis phantom with the lumen region 5 mm the calcification blooming artifact was subtracted in the application of the mixture of Gaussian filtering and K- Clustering algorithm, and the value was close to the actual calcification region. These results may help to accurately diagnose coronary artery calcification stenosis.

• 한국방사선학회논문지
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• 제14권1호
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• pp.61-68
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• 2020

본 연구에서는 CT 혈관조영 영상에서 조영제 희석비율에 따른 Blooming 인공물 발생의 상관성에 대하여 알아보고자 한다. 3D 프린터를 이용하여 PLA(Poly Lactic Acid)재질의 구형 팬텀을 자체 제작하였고 구형 팬텀 내부에 조영제와 식염수의 비율을 100:0부터 10:90으로 희석하여 총 10세트를 준비하였다. 이후 CT 횡단면 영상을 얻고 raw 데이터를 최대강도투사법, 다중평면 재구성 기법으로 재구성하여 각각 횡단면, 시상면, 관상면의 영상을 얻었다. 검사 후 얻은 영상의 구형 팬텀의 직경을 각각 30회씩 총 1800회 측정하였다. 측정결과, 다중 평면 재구성 기법 중 관상면에서 20:80으로 희석하였을 때 20.47±0.05 mm로 가장 작게 측정되었다(p<0.05). 마찬가지로 최대강도투사법 중 시상면에서 20:80으로 희석하였을 때 20.39±0.08 mm로 가장 작게 측정되었다(p<0.05). 희석비율과 측정 크기의 상관성 분석에서는 모든 재구성 영상에서 강한 음의 상관성을 확인하였다(p<0.05). 결론적으로 조영제 희석비율이 높을수록 혈관의 실측을 측정하기 어려우며 이에 대한 원인으로 Blooming 인공물이 있음을 확인하였다. 따라서 실측에 관한 추후 연구에서 본 연구가 기초자료를 제공할 수 있을 것이라 사료된다.

• Investigative Magnetic Resonance Imaging
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• 제19권2호
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• pp.107-113
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• 2015

Purpose: Susceptibility weighted imaging (SWI) is a new magnetic resonance technique that can exploit the magnetic susceptibility differences of various tissues. Intracranial hemorrhage (ICH) looks a dark blooming on the magnitude images of SWI. However, the pattern of ICH on phase images is not well known. The purpose of this study is to characterize hemorrhagic lesions on the phase images of SWI. Materials and Methods: We retrospectively enrolled patients with ICH, who underwent both SWI and precontrast CT, between 2012 and 2013 (n = 95). An SWI was taken, using the 3-tesla system. A phase map was generated after postprocessing. Cases with an intracranial hemorrhage were reviewed by an experienced neuroradiologist and a trainee radiologist, with 10 years and 3 years of experience, respectively. The types and stages of the hemorrhages were determined in correlation with the precontrast CT, the T1- and T2-weighted images, and the FLAIR images. The size of the hemorrhage was measured by a one- directional axis on a magnitude image of SWI. The phase values of the ICH were qualitatively evaluated: hypo-, iso-, and hyper-intensity. We summarized the imaging features of the intracranial hemorrhage on the phase map of the SWI. Results: Four types of hemorrhage are observed: subdural and epidural; subarachnoid; parenchymal hemorrhage; and microbleed. The stages of the ICH were classified into 4 groups: acute (n = 34); early subacute (n = 11); late subacute (n = 15); chronic (n = 8); stage-unknown microbleeds (n = 27). The acute and early subacute hemorrhage showed heterogeneous mixed hyper-, iso-, and hypo-signal intensity; the late subacute hemorrhage showed homogeneous hyper-intensity, and the chronic hemorrhage showed a shrunken iso-signal intensity with the hyper-signal rim. All acute subarachnoid hemorrhages showed a homogeneous hyper-signal intensity. All parenchymal hemorrhages (> 3 mm) showed a dipole artifact on the phase images; however, microbleeds of less than 3 mm showed no dipole artifact. Larger hematomas showed a heterogeneous mixture of hyper-, iso-, and hypo-signal intensities. Conclusion: The pattern of the phase value of the SWI showed difference, according to the type, stage, and size.