An improved method for measurement of target-to-Background ratio in assessing mediastinal lesions on 18F-FDG coincidence SPECT/CT imaging

Peng Wang, Zhaowei Meng, Jian Tan, Qiang Jia, Fuhai Zhang

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


Objectives: Target-to-Background ratio (T/B) is a commonly used semiquantitative index in F-FDG dual-head coincidence single-photon emission computed tomography (c-SPECT) imaging. However, because of different methods of measurement, T/B varies. This study used F-FDG c-SPECT/CT imaging of mediastinal lesions to analyze the impact of different Backgrounds for determining T/Bs. Methods: Thirty-five patients with mediastinal lesions underwent thoracic F-FDG c-SPECT/CT with 1-inch crystals. According to integrated CT, five types of Backgrounds were precisely positioned as airway, fat, mediastinal space, vascular blood, and heart areas. Corresponding T/Bs (T/BA, T/BF, T/BM, T/BV, and T/BH) of benign and malignant lesions were calculated. Two-way analysis of variance, receiver-operating characteristic curves, and coefficient of variation were performed for statistical analyses. Results: Seventeen benign lesions and 23 malignant lesions were identified in patients with histological confirmation. Only T/BA was significantly different from other T/Bs in both the benign and malignant groups; yet, there were no significant differences in the remaining T/Bs (P<0.01). On the basis of receiver-operating characteristic curves, cutoff values, sensitivity, specificity, positive predictive value and negative predictive value, the accuracy of diagnosis followed the order of T/BV>T/BM> T/BA>T/BF>T/BH, and T/BV showed optimal sensitivity (87.0%), specificity (76.5%), and accuracy (82.5%) of diagnosis. Vascular blood and mediastinal space areas, which were in the same homogeneous subset, possessed the significantly lowest coefficient of variation, indicating good homogeneity in the regions. Conclusion: Choosing different Backgrounds has a great impact on the diagnostic accuracies of F-FDG c-SPECT/CT imaging of mediastinal lesions. The large blood vessel area is the best Background choice for optimization of T/B calculation.

Original languageEnglish
Pages (from-to)398-404
Number of pages7
JournalNuclear Medicine Communications
Issue number5
StatePublished - May 2010
Externally publishedYes


  • 18F-FDG
  • Dual-head coincidence imaging
  • Mediastinal lesion
  • Single-photon emission computed tomography/computed tomography
  • Target-to-background ratio


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