Side-by-side reading of PET and CT scans in oncology: which patients might profit from integrated PET/CT?

Eur J Nucl Med Mol Imaging. 2004 Nov;31(11):1456-61. doi: 10.1007/s00259-004-1593-y. Epub 2004 Jul 10.


Purpose: Most early publications on integrated positron emission tomography/computed tomography (PET/CT) devices have reported the new scanner generation to be superior to conventional PET. However, few of these studies have analysed the situation where, in addition to PET, a current CT scan is available for side-by-side viewing. This fact is important, because combined PET/CT or a software-based fusion of the two modalities may improve diagnosis only in cases where side-by-side reading of PET and CT data does not lead to a definitive diagnosis. The aim of this study was to analyse which patients will profit from integrated PET/CT in terms of lesion characterization.

Methods: A total of 328 consecutively admitted patients referred for PET in whom a current CT scan was available were included in the study. The localization of all pathological PET lesions, as well as possible infiltration of adjacent anatomical structures, was assessed.

Results: Of 467 pathological lesions, 94.0% were correctly assessed with respect to localization and infiltration by either conventional PET alone (51.6%) or combined reading of PET and the already existing CT scans (42.4%). Hence, in only 6.0% of all lesions, affecting 6.7% of all patients, could evaluation have profited from integrated PET/CT.

Conclusion: We conclude that side-by-side viewing of PET and CT scans is essential, as in 42.4% of all cases, combined viewing was important for a correct diagnosis in our series. In up to 6.7% of patients, integrated PET/CT might have given additional information, so that in nearly 50% of patients some form of combined viewing of PET and CT data is needed for accurate lesion characterization.

Publication types

  • Clinical Trial
  • Validation Study

MeSH terms

  • Adult
  • Aged
  • Female
  • Humans
  • Image Enhancement / methods*
  • Male
  • Middle Aged
  • Neoplasms / diagnostic imaging*
  • Positron-Emission Tomography / methods*
  • Reproducibility of Results
  • Sensitivity and Specificity
  • Single-Blind Method
  • Subtraction Technique*
  • Systems Integration
  • Tomography, X-Ray Computed / methods*