FAO의 세계 산림자원 평가결과

손철호 한국농촌경제연구원 2002 세계농업 Vol.20 No.-

3.OT MR 기기를 이용한 확산강조영상에서 b Value의 증가에 따른 정상 뇌의 신호강도의 변화

손철호,Son, Cheol-Ho 대한영상의학회 2003 대한영상의학회지 Vol.49 No.6

목적:확산강조영상에서 b value를 증가시켰을 때 정상 성인 뇌의 신호강도의 변화를 알아보고 대상과 방법:임상적으로 신경학적 증상이 없고 T2 강조영상에서 이상 소견이 관찰되지 않는 21명의 건강한 지원자를 대상으로 하였다.자기공명영상은 3.0T MR 기기를 이용하였다.스핀에코 EPI 기법을 이용하여,b value를 0,1,000,1,500,2,000,2,500,3,000 s/mm$^2$으로 점점 증가시키면서 축상으로 6쌍의 확산강조영상을 얻었다.영상조건중 TE를 제외한 모든 다른 조건은 동일하게 사용하였다.영상의 분석은,정성적으로는 각각의 b value 확산강조영상에서 정상 뇌회백질의 신호변화를 시각적으로 보았고,정량적으로는 각각의 b value 확산강조영상에서 6군데의 해부학적 위치 (전두부 및 두정부 백질,뇌량의 슬 및 팽부,내포의 후변연,시상)에서 신호대잡음비를 구하여 이들의 평균 신호대잡음비를 b value 1,000 s/mm$^2$의 신호대잡음비와 비교하였다. 결과:정성적 분석에서는,b value를 증가시킴에 따라 뇌 회질과 백질의 모든 구조물의 신호가 감소하였다.특히 b=3,000 s/mm$^2$에서의 영상은 잡음이 매우 심했다.뇌 백질은 회질에 비해 경사자장을 증가시킴에 따라 점차 신호강도가 높게 관찰되었다.특히 난형중심,내포의 후변연, 시방사,상소뇌각교차,뇌량의 팽부등의 구조물이 고신호강도로 관찰되었지만 예외적으로 뇌량의 슬부는 중간 저음영을 보였다.정량적 분석에서도,경사자장을 증가시킴에 따라 각각의 해부학적 위치의 평균신호대잡음비는 b value가 1,000 s/mm$^2$일 때의 확산강조영상에 비해 각각평균 0.71(b=1,500 s/mm$^2$),0.52 (b=2,000 s/mm$^2$),0.41 (b=2,500 s/mm$^2$),0.33 (b=3,000s/mm$^2$)으로 감소되었다. 결론:확산강조 경사자장의 세기를 증가시킴에 따라 영상의 신호대잡음비는 감소하며 특히 b value 3,000 s/mm$^2$에서 심하게 나타났고,백질은 회질에 비해 상대적으로 신호강도가 점점 높게 관찰되었다.이러한 정상 뇌회백질 신호변화의 인지는 판독의 오류를 막는데 매우 중요할것으로 생각된다. Purpose: Using diffusion-weighted MR imaging (DWI), to evaluate the signal intensity characteristics of normal adult brain as diffusion gradient strength (b value) increases from 1,000 to 3,000 s/mm$^2$. Materials and Methods: Twenty-one healthy volunteers with neither neurologic symptoms nor pathologic findings at axial and sagittal T2-weighted MR imaging were involved in this study. All images were obtained with a 3.0T MR scanner. Six sets of spin-echo echo-planar images were acquired in the axial plane using progressively increasing strengths of diffusion-sensitizing gradients (corresponding to b values of 0, 1,000, 1,500, 2,000, 2,500, and 3,000 s/mm$^2$). All imaging paremeters other than TE remained constant. Changes in normal white-gray matter signal intensity observed at variable b-value DWI were qualitatively analysed, and the signal-to-noise ratios (SNRs) in six anatomic regions (frontal and parietal white matter, genu and splenium corporis callosi, the posterior limb of the internal capsule, and the thalamus) quantitatively, and the ratios were averaged and compared with the average SNR of 1,000 s/mm DWI. Results: As gradient strength increased from 1,000 to 3,000 s/mm$^2$, both gray-and white-matter structures diminished in signal intensity, and images obtained at a b value of 3,000 s/mm$^2$ appeared very noisy. White matter became progressively hyperintense to gray matter as the diffusion sensitizing gradient increased, especially at the centrum semiovale, the posterior limb of the internal capsule, and the splenium corporis callosi, but the genu corporis callosi, showed exceptional intermediate low signal intensity. At quantitative assessment, the signal-to-noise ratio decreased as the diffusion sensitizing gradient increased. Relative to the images obtained at a b value of 1,000 s/mm$^2$, average SNRs were 0.71 (b=1,500 s/mm$^2$), 0.52 (b=2,000 s/mm$^2$), 0.41(b=2,500 s/mm$^2$), 0.33 (b=3,000 s/mm$^2$). Conclusion: As the diffusion sensitizing gradient increased, the signal-to-noise ratio of brain structures diminished, especially at a b value of 3,000 s/mm$^2$, and white matter became relatively hyperintense compared to gray matter. In order to avoid misdiagnosis, it is important to be aware of the nature of normal changes in the signal intensity of gray-white matter occurring at high-b-value DWI

<연구 자료> 산림농업의 추진 실태와 정책 방향

손철호,석현덕 한국농촌경제연구원 2006 농촌경제 Vol.29 No.1

This study tried to find the way of encouraging agroforestry practices in Korea by way of investigating current situations of agroforestry and finding the problems of performing policies for agroforestry. Agroforestry started as a name of "a complex management of forest for multiple uses" in Korea began in the year of 1999 in order to provide interim incomes to the owners of forest who were mostly suffered by the lack of incomes from the investment of forests. Most of investors in agroforestry felt that financial supports from the government were always insufficient especially needed after the first year of investments established. They also complained the process of administration were slow and out of date in many cases. The code of practices of individual agroforestry models should be developed and distributed by way of educating forest owners. In order to activate agroforestry practices, regional agroforestry clusters can be a solution of acquiring economies of scale and value adding processes by processing a large amount of agroforestry products in the confined area.

지속적인 산림경영을 위한 산림인증제도(하)

손철호 한국산림경영인협회 1998 山林經營 Vol.134 No.-

최근 전세계적으로 강구되고 있는 지속가능한 산림경영을 위한 수단의 하나로서 선진국 및 목재생산국을 중심으로 급속하게 전개되고 있는 산림인증제도에 대하여 지난호에 이어 이번호에 소개하고자 한다. 산림인증제도는 국제기구 또는 독립된 기구에서 마련한 기준에 부합되게 산림을 관리하였을 경우 이를 인증하는 제도로서 만일 이 제도가 정착될 경우, 산림을 관리하고 있는 신주들이나 독림가에게는 매우 의미있는 제도라 할 수 있다. 이글은 World Wildlife Fund(WWF)에서 발행한 산림인증제도에 관한 소책자를 중심으로 번역한 것임을 밝혀둔다.

급성 요통환자에서 재활도수치료의 효과

손철호,오상향,김민성,김수아,남기석,박상일,최은,이양균 大韓再活醫學會 1999 Annals of Rehabilitation Medicine Vol.23 No.4

Fluid Attenuated Inversion Recovery (FLAIR) Imaging of the Normal Brain: Comparisons between Under the Conditions of 3.0 Tesla and 1.5 Tesla

손철호,Robert J. Sevick,Richard Frayne,장혁원,김상표,김대광 대한영상의학회 2010 Korean Journal of Radiology Vol.11 No.1

Objective: The aim of this study was to evaluate the differences in normal brain MRI findings between under 3.0 Tesla (T) and 1.5T MRI conditions with the use of the fluid attenuated inversion recovery (FLAIR) sequences. Materials and Methods: Eleven normal adults underwent imaging with the use of the FLAIR sequences on both 1.5T and 3.0T scanners. Two neuroradiologists compared the signal intensity (SI) of the centrum semiovale (CS), pulvinar thalami (PT) and normal iron deposit structures (IDSs) on the 3.0T and 1.5T FLAIR images, and they evaluated three MRI findings qualitatively: high SI of CS; low SI of PT; low SI of IDS. We also evaluated signal-to-noise ratios (SNRs) for the CS, PT, red nucleus and cerebellar dentate nucleus on the FLAIR images. Results: Based on qualitative analyses, the 3.0T FLAIR images showed all three MRI findings for all cases. Low SI for the PT in seven cases (64%), high SI of the CS in one case (9%) and low SI of the cerebellar dentate nucleus in one case (9%) were visualized only on 3.0T FLAIR images. The mean SNRs of the PT, red nucleus and dentate nucleus in patients where 3.0T FLAIR imaging was performed were significantly lower as compared with the SNRs on 1.5T FLAIR images. The SNR of the CS was not significantly different between under the two magnetic field strengths (p > 0.05). Conclusion: We have demonstrated that normal, high and low SIs of the CS, PT and IDS on 3.0T FLAIR images were depicted more frequently and more prominently as compared with those on 1.5T FLAIR images in normal adult brains. Objective: The aim of this study was to evaluate the differences in normal brain MRI findings between under 3.0 Tesla (T) and 1.5T MRI conditions with the use of the fluid attenuated inversion recovery (FLAIR) sequences. Materials and Methods: Eleven normal adults underwent imaging with the use of the FLAIR sequences on both 1.5T and 3.0T scanners. Two neuroradiologists compared the signal intensity (SI) of the centrum semiovale (CS), pulvinar thalami (PT) and normal iron deposit structures (IDSs) on the 3.0T and 1.5T FLAIR images, and they evaluated three MRI findings qualitatively: high SI of CS; low SI of PT; low SI of IDS. We also evaluated signal-to-noise ratios (SNRs) for the CS, PT, red nucleus and cerebellar dentate nucleus on the FLAIR images. Results: Based on qualitative analyses, the 3.0T FLAIR images showed all three MRI findings for all cases. Low SI for the PT in seven cases (64%), high SI of the CS in one case (9%) and low SI of the cerebellar dentate nucleus in one case (9%) were visualized only on 3.0T FLAIR images. The mean SNRs of the PT, red nucleus and dentate nucleus in patients where 3.0T FLAIR imaging was performed were significantly lower as compared with the SNRs on 1.5T FLAIR images. The SNR of the CS was not significantly different between under the two magnetic field strengths (p > 0.05). Conclusion: We have demonstrated that normal, high and low SIs of the CS, PT and IDS on 3.0T FLAIR images were depicted more frequently and more prominently as compared with those on 1.5T FLAIR images in normal adult brains.

표고의 수요전망 및 시장개방에 대한 대응방안

손철호,윤여창 ( Cheol Ho Sohn,Yeo Chang Youn ) 한국산림경제학회 1994 산림경제연구 Vol.2 No.1

유엔환경개발회의 이후 산림분야 추진성과

손철호 한국농촌경제연구원 2001 세계농업 Vol.11 No.-

일본, 임산버섯 수급동향

손철호 한국농촌경제연구원 2004 세계농업 Vol.50 No.-

Imaging Findings of Brain Death on 3-Tesla MRI

손철호,이화평,박준범,장혁원,김일만,김은희,박의준,김형태,구정훈 대한영상의학회 2012 Korean Journal of Radiology Vol.13 No.5

Objective: To demonstrate the usefulness of 3-tesla (3T) magnetic resonance imaging (MRI) including T2-weighted imaging (T2WI), diffusion weighted imaging (DWI), time-of-flight (TOF) magnetic resonance angiography (MRA), T2*-weighted gradient recalled echo (GRE), and susceptibility weighted imaging (SWI) in diagnosing brain death. Materials and Methods: Magnetic resonance imaging findings for 10 patients with clinically verified brain death (group I) and seven patients with comatose or stuporous mentality who did not meet the clinical criteria of brain death (group II) were retrospectively reviewed. Results: Tonsilar herniation and loss of intraarterial flow signal voids (LIFSV) on T2WI were highly sensitive and specific findings for the diagnosis of brain death (p < 0.001 and < 0.001, respectively). DWI, TOF-MRA, and GRE findings were statistically different between the two groups (p = 0.015, 0.029, and 0.003, respectively). However, cortical high signal intensities in T2WI and SWI findings were not statistically different between the two group (p = 0.412 and 1.0, respectively). Conclusion: T2-weighted imaging, DWI, and MRA using 3T MRI may be useful for diagnosing brain death. However, SWI findings are not specific due to high false positive findings.