Herder risk model

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British Thoracic Society (BTS) guidelines for pulmonary nodules recommend the application of the Herder risk model in predicting malignancy in pulmonary nodules.

The Herder model  predicts the risk of malignancy in solid pulmonary nodules using patient characteristics, nodules characteristics, and the degree of FDG uptake on PET-CT.

Using the Herder model, pulmonary nodule FDG uptake is classified into four categories. Herder et al did not suggest specific objective values for each level, however, other studies have . The BTS recommend using the following scale:

  • no uptake: uptake indiscernible from background lung tissue
  • faint uptake: uptake less than or equal to mediastinal blood pool
  • moderate uptake: uptake greater than mediastinal blood pool
  • intense uptake: uptake markedly greater than mediastinal blood pool (not strictly defined but 3x mediastinal blood pool would be considered intense)