title: Quantification of metabolic tumor activity and burden in patients with non-small-cell lung cancer: Is manual adjustment of semiautomatic gradient-based measurements necessary?
abstract: OBJECTIVE
  Metabolic tumor burden (MTB) measurements including metabolic tumor volume and total lesion glycolysis have been shown to have prognostic value in non-small-cell lung cancer (NSCLC). The calculation of MTB typically utilizes software to semiautomatically draw volumes of interest around the tumor, which are subsequently manually adjusted by the radiologist to include the entire tumor. The manual adjustment step can be time-consuming and observer-dependent. We compared the agreement of MTB values obtained using the semiautomatic method with and without manual adjustment in NSCLC patients.
  
  
  METHODS
  This IRB-approved prospective study included 134 patients with histologically proven NSCLC who underwent fluorine-18 fluorodeoxyglucose PET/computed tomography. The MTB of the primary tumor was measured with a semiautomatic gradient-based method without manual adjustment (the semiautomatic gradient method) and with manual adjustment (the manually adjusted semiautomatic gradient method) by two radiologists using the MIM PETedge tool. The paired t-test, Wilcoxon signed-rank test, and concordance correlation coefficient (CCC) were calculated to evaluate the agreement between MTB measures obtained with these two methods, as well as agreement between the two radiologists for each method.
  
  
  RESULTS
  Maximum standardized uptake value was identical between the two methods. No statistically significant difference was present for peak standardized uptake value, metabolic tumor volume, and total lesion glycolysis values between the two methods (P=0.23, 0.45, and 0.37, respectively). Excellent agreement between the two methods was found in terms of CCC (CCC>0.98 for all measures). Interobserver reliability was excellent for all measures (CCC>0.90).
  
  
  CONCLUSIONS
  The semiautomatic gradient-based tumor-segmentation method can be used without the additional manual adjustment step for MTB quantification of primary NSCLC tumors.
authors.affiliation: Departments of aRadiology bPublic Health Sciences, University of Chicago, Chicago, Illinois, USA cPET/CT Center, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China dDepartment of Nuclear Medicine, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China.
authors.forename: Piotr
authors.initials: P
authors.lastname: Obara
authors.forename: Haiping
authors.initials: H
authors.lastname: Liu
authors.forename: Kristen
authors.initials: K
authors.lastname: Wroblewski
authors.forename: Chen-Peng
authors.initials: CP
authors.lastname: Zhang
authors.forename: Peng
authors.initials: P
authors.lastname: Hou
authors.forename: Yulei
authors.initials: Y
authors.lastname: Jiang
authors.forename: Ping
authors.initials: P
authors.lastname: Chen
authors.forename: Yonglin
authors.initials: Y
authors.lastname: Pu
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001331:Automation; D002289:Carcinoma, Non-Small-Cell Lung / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008175:Lung Neoplasms / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D049268:Positron-Emission Tomography; D012984:Software; D014057:Tomography, X-Ray Computed; D047368:Tumor Burden; D055815:Young Adult