The Korean Journal of Nuclear Medicine (대한핵의학회지)

The Korean Society of Nuclear Medicine (대한핵의학회)
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Improving Diagnostic Accuracy for Malignant Nodes and N Staging in Non-Small Cell Lung Cancer Using CT-Corrected FDG-PET

비소세포폐암에서 CT-보정 양전자단층촬영술을 이용한 악성 림프절 평가 및 N 병기 결정 성적 향상

  • Lee, Eun-Jeong (Department of Nuclear Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine) ;
  • Choi, Joon-Young (Department of Nuclear Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine) ;
  • Lee, Kyung-Soo (Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine) ;
  • Chung, Hyun-Woo (Department of Nuclear Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine) ;
  • Lee, Su-Jin (Department of Nuclear Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine) ;
  • Cho, Young-Seok (Department of Nuclear Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine) ;
  • Choi, Yong (Department of Nuclear Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine) ;
  • Choe, Yearn-Seong (Department of Nuclear Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine) ;
  • Lee, Kyung-Han (Department of Nuclear Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine) ;
  • Kwon, O-Jung (Department of Internal Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine) ;
  • Shim, Young-Mog (Department of Thoracic Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine) ;
  • Kim, Byung-Tae (Department of Nuclear Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine)
  • 이은정 (성균관대학교 의과대학 삼성서울병원 핵의학과) ;
  • 최준영 (성균관대학교 의과대학 삼성서울병원 핵의학과) ;
  • 이경수 (성균관대학교 의과대학 삼성서울병원 영상의학과) ;
  • 정현우 (성균관대학교 의과대학 삼성서울병원 핵의학과) ;
  • 이수진 (성균관대학교 의과대학 삼성서울병원 핵의학과) ;
  • 조영석 (성균관대학교 의과대학 삼성서울병원 핵의학과) ;
  • 최용 (성균관대학교 의과대학 삼성서울병원 핵의학과) ;
  • 최연성 (성균관대학교 의과대학 삼성서울병원 핵의학과) ;
  • 이경한 (성균관대학교 의과대학 삼성서울병원 핵의학과) ;
  • 권오정 (성균관대학교 의과대학 삼성서울병원 내과) ;
  • 심영목 (성균관대학교 의과대학 삼성서울병원 흉부외과) ;
  • 김병태 (성균관대학교 의과대학 삼성서울병원 핵의학과)
  • Published : 2005.08.31
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Abstract

Purpose: We investigated prospectively whether the interpretation considering the patterns of FDG uptake and the findings of unenhanced CT for attenuation correction can improve the diagnostic accuracy for assessing malignant lymph node (LN) and N stage in non-small cell lung cancor (NSCLC) using CT-corrected FDG-PET (PET/CT). Materials & Methods: Subjects were 91 NSCLC patients (M/F 62/29, age: $60{\pm}9$ yr) who underwent PET/CT before in dissection. We evaluated the maximum SUV (maxSUV), patterns of FDG uptake, short axis diameter, and calcification of LN showing abnormally increased FDG uptake. Then we investigated criteria improving the diagnostic accuracy and correlated results with postoperative pathology. In step 1, in was classified as benign or malignant based on maxSUV only. In step 2, LN was regarded as benign if it had lower maxSUV than the cut-off value of step 1 or it had calcification irrespective of its maxSUV. In step 3, LN regarded as malignant in step 2 was classified as benign if they had indiscrete margin of FDG uptake. Results: Among 432 LN groups surgically resected (28 malignant, 404 benign), 71 showed abnormally increased FDG uptake. We determined the cut-off as maxSUV=3.5 using ROC curve analysis. The sensitivity, specificity, and accuracy for assessing malignant LN were 64.3%, 86.9%, 85.4% in step 1, 64.3%, 95.0%, 93.1% in step 2, and 57.1%, 98.0%, 95.4% in step3, respectively. The accuracy for assessing N stage was 64.8% in step 1, 80.2% in step 2, and 85.7% in step 3. Conclusion: interpreting PET/CT, consideration of calcification and shape of the FDG uptake margin along with maxSUV can improve the diagnostic accuracy for assessing malignant involvement and N stage of hilar and mediastinal LNs in NSCLC.

목적: 비소세포성폐암(NSCLC)의 FDG-PET 판독 시 SUV만 진단기준으로 사용하면 우리나라와 같이 만성 염증성 폐질환이 호발하는 지역에서는 폐문 및 종격동 림프절에 대한 위양성률이 높다. 이에 최근 국내에 도입된 CT-보정 FDG-PET (PET/CT)을 이용하여 SUV 외에 FDG 섭취양상 및 CT영상에서 림프절 석회화 등의 다른 기준을 어떻게 적용하면 림프절의 악성 유무 판정 및 N 병기 결정에 있어 검사의 정확도가 높아질 수 있는지 전향적으로 알아보았다. 대상 및 방법 : 림프절 절제술을 받기 전에 PET/CT를 시행한 91명의 NSCLC 환자를 대상으로 하였다(남/여: 62/29, 평균나이: $60{\pm}9$ yr). 종격동 대혈관보다 FDG 섭취가 증가되어 있는 폐문과 종격동 림프절의 최대 SUV (maxSUV)와 단경을 측정하고, FDG 섭취증가 병변의 경계 및 석회화 유무를 파악하였다. 이 기준들을 이용하여 PET/CT 소견을 세 단계로 나누어 각각의 진단 성적을 병리결과와 비교하였다. 1단계에서는 maxSUV만을 진단기준으로 사용하였다. 2단계 에서는 1단계에서 정한 cut-off 보다 낮은 maxSUV를 가지는 림프절 또는 높은 maxSUV를 가지더라도 CT 영상에서 석회화가 있거나 높은 attenuation을 보이는 림프절을 양성으로 분류하였다. 3단계에서는 2단계에서 양성으로 분류한 림프절 및 2단계에서 악성으로 분류된 림프절 중 FDG 섭취증가의 경계가 명확하지 않은 림프절을 양성으로 하였다. 결과: 수술로 절제된 총 432개의 림프절 중 28개가 악성, 404개가 양성이었다. 71개가 비정상적인 FDG 섭취증가를 보였다. ROC 곡선 분석을 이용해 구한 cut-off는 maxSUV=3.5였다. 악성 림프절 판정에 대한 민감도, 특이도, 정확도는 각각 1단계에서 64.3%, 86.9%. 85.4%. 2단계 64.3%, 95.0%, 93.1%, 그리고 3단계 57.1%, 98.0%, 95.4%였다. N 병기 일치율은 1단계 64.8%, 2단계 80.2%, 3단계 85.7%였다. 결론: NSCLC 환자의 PET/CT 판독 시 림프절의 FDG 섭취증가 정도뿐만 아니라 병변의 석회화 유무 및 FDG 섭취증가의 경계부분 모양을 함께 고려하면 폐문 및 종격동 림프절의 악성 여부 평가 및 N 병기 결정에 있어 더 탁월한 진단성적을 기대할 수 있을 것으로 생각된다.

Keywords

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