Krenning score of neuroendocrine tumor uptake

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The Krenning score is a proposed semi-quantitative method of assessing the degree of tracer uptake on octreotide scintigraphy.

Parameters

Initially designed for assessment of In-DTPA on planar imaging, the Krenning score is applicable to SPECT or PET/CT using various radiopharmaceuticals.

Determination of the Krenning score requires comparison to the liver and spleen (or kidney if not applicable).

Relative uptake score
  • 0: none
  • 1: much lower than liver
  • 2: slightly less than or equal to liver 
  • 3: greater than liver
  • 4: greater than spleen
Important points
  • the commonest contemporary application of the Krenning score is to assess candidacy for peptide receptor radionuclide therapy (PRRT), such as Lu-DOTATATE, usually with a score greater than 2
  • false-positive localization in general for somatostatin scintigraphy may be as high as 12% and thus scoring and interpretation should take place in the appropriate clinical context (e.g. serum chromogranin A, urine 5-HIAA, and tumor grade)
  • the scale has shown potential for use in other somatostatin receptor imaging modalities such as Ga-DOTATATE PET/CT

History and etymology

The notion of grading neuroendocrine tumor uptake was introduced by Eric Krenning, a Dutch physician, who led whole-body efforts into somatostatin receptor imaging .