초음파에서 얻은 간-신장 에코비를 이용한 지방간과 복부 지방량과의 상관 관계에 관한 연구 = Correlation between Abdominal Fat Amount and Fatty Liver, using Liver to Kidney Echo Ratio on Ultrasound

다국어 초록 (Multilingual Abstract)

Purpose: It has been generally recognized that fatty liver can often be seen in the obese population. This study was conducted in order to evaluate the association between fatty liver and abdominal fat volume.
Materials and Methods: A total of 105 patients who visited our obesity clinic in the recent three years underwent fat CT scans and abdominal US. Attenuation difference between liver and spleen on CT was considered as a reference standard for the diagnosis of fatty liver. On US, the echogenicity of the liver parenchyma was measured in three different regions of interest (ROI) close to the adjacent right kidney in the same slice, avoiding vessels, bile duct, and calcification. Similar measurements were performed in the right renal cortex. The mean values were calculated automatically on the histogram of the ROI using the PACS program. The hepatorenal echogenicity ratio (HER; mean hepatic echogenicity/ mean renal echogenicity) was then calculated.
Abdominal fat volume was measured using a 3 mm slice CT scan at the L4/5 level and was calculated automatically using a workstation. Abdominal fat was classified according to total fat (TF), visceral fat (VF), and subcutaneous fat (SF). We used Pearson’s bivariate correlation method for assessment of the correlation between HER and TF, VF, and SF, respectively.
Results: Significant correlation was observed between HER and abdominal fat (TF,VF, and SF). HER showed significant correlation with VF and TF (r = 0.491 and 0.402,respectively; p = 0.000). The correlation between HER and SF (r = 0.255, p = 0.009)was less significant than for VF or TF.
Conclusions: Fat measurement (HER) by hepatic ultrasound correlated well with the amount of abdominal fat. In particular, the VF was found to show a stronger association with fatty liver than SF.

국문 초록 (Abstract)

목적: 일반적으로 비만 환자들에서 지방간이 자주 발견되는 것으로 알려져 있다. 이 연구의 목적은 지방간과 복부지방량과의 상관 관계가 있는지 알아보는 것이다.
연구방법: 최근 3년간 본원의 비만 클리닉에 방문한 환자 중 지방 프로토콜의 CT와 복부 초음파를 동시에 시행한 105명의 환자를 대상으로 하였다. CT에서 간과 비장의감쇄 차이를 지방간 값의 표준으로 간주하였으며, 복부초음파에서 혈관, 간 내 담관, 석회화 등을 피해서 같은 슬라이스의 인접한 부위의 간과 우측 신장의 피질 부위에 3개의 다른 ROI를 거치하여 간과 신장의 에코를 측정하였다.
평균값은 PACS 프로그램의 ROI 히스토그램에서 자동으로 계산되었으며, 이를 이용하여 간-신장 초음파 에코비(hepatorenal echogenicity ratio: HER)를 계산하였다.
CT는 요추 4/5 수준에서 약 3 mm 두께의 구획을 촬영하였고, 워크스테이션을 이용하여 지방 볼륨을 자동적으로추출하였다. 복부 지방은 전체지방 (TF), 내장지방 (VF),그리고 표피지방 (SF)으로 나누었다. 지방간과 복부 지방구획량과의 상관 관계를 알기 위해, HER 값과 TF, VF, 그리고 SF 사이의 관계를 Pearson’s bivariate correlation 방법을 이용하여 알아보았다.
결과: HER와 복부지방들 (TF, VF, SF)과 의미있는 상관관계가 있었다. 특히 HER와 VF, TF와 의미있는 상관관계가 있었다 (r = 0.491 and 0.402, 각각 p = 0.000).
HER와 SF 사이에서는 VF와 TF에 비해서는 다소 약한 상관관계가 있었다 (r = 0.255, p = 0.009).
결론: 간초음파에 의해 측정된 지방간 수치 (HER)는 복부의 지방량과의 연관성이 높았다. 복부 지방 구획 중 특히내장 지방층 부피 (VF)가 표피 지방층 부피 (SF)보다 초음파에서 측정한 지방간 수치와의 연관지수가 높았다.

참고문헌 (Reference)

• 1 Anjana M, "Visceral and central abdominal fat and anthropometry in relation to diabetes in Asian Indians" 27 : 2948-2953, 2004
• 2 Hamaguchi M, "The metabolic syndrome as a predictor of nonalcoholic fatty liver disease" 143 : 722-728, 2005
• 3 Wajchenberg BL, "Subcutaneous and visceral adipose tissue: their relation to the metabolic syndrome" 21 : 697-738, 2000
• 4 Bellentani S, "Prevalence of and risk factors for hepatic steatosis in Northern Italy" 132 : 112-117, 2000
• 5 Angulo P, "Nonalcoholic fatty liver disease" 346 : 1221-1231, 2002
• 6 Clark JM, "Nonalcoholic fatty liver disease" 122 : 1649-1657, 2002
• 7 Limanond P, "Macrovesicular hepatic steatosis in living related liver donors: correlation between CT and histologic findings" 230 : 276-280, 2004
• 8 Park SH, "Macrovesicular hepatic steatosis in living liver donors: use of CT for quantitative and qualitative assessment" 239 : 105-112, 2006
• 9 Hamer OW, "Fatty liver: imaging patterns and pitfalls" 26 : 1637-1653, 2006
• 10 Omagari K, "Fatty liver in non-alcoholic non-overweight Japanese adults: incidence and clinical characteristics" 17 : 1098-1105, 2002
• 11 Scatarige JC, "Fatty infiltration of the liver: ultrasonographic and computed tomographic correlation" 3 : 9-14, 1984
• 12 Lee CH, "Fade-out sign on hepatic tissue harmonic compound sonography: a value as a new sign in the diagnosis of fatty liver" 80 : e258-e262, 2011
• 13 Nugent C, "Evaluation and management of obesity-related nonalcoholic fatty liver disease" 4 : 432-441, 2007
• 14 Le TA, "Effect of colesevelam on liver fat quantified by magnetic resonance in nonalcoholic steatohepatitis: a randomized controlled trial" d56 : 922-932, 2012
• 15 Webb M, "Diagnostic value of a computerized hepatorenal index for sonographic quantification of liver steatosis" 192 : 909-914, 2009
• 16 Jang SA, "Correlation of fatty liver and abdominal fat distribution using a simple fat computed tomography protocol" 17 : 3335-3341, 2011
• 17 Park YS, "Biopsy-proven Nonsteatotic Liver in Adults: Estimation of Reference Range for Difference in Attenuation between the Liver and the Spleen at Nonenhanced CT" RADIOLOGICAL SOC NORTH AMERICA 258 (258): 760-766, 201103
• 18 Fox CS, "Abdominal visceral and subcutaneous adipose tissue compartments: association with metabolic risk factors in the framingham heart study" 116 : 39-48, 2007