The Krenning score is a proposed semi-quantitative method of assessing the degree of tracer uptake on octreotide scintigraphy.
Initially designed for assessment of 111In-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
- the commonest contemporary application of the Krenning score is to assess candidacy for peptide receptor radionuclide therapy (PRRT), such as 177Lu-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 68Ga-DOTATATE PET/CT 2
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 1.
- 1. Krenning EP, Bakker WH, Breeman WA, Koper JW, Kooij PP, Ausema L, Lameris JS, Reubi JC, Lamberts SW. Localisation of endocrine-related tumours with radioiodinated analogue of somatostatin. (1989) Lancet (London, England). 1 (8632): 242-4. doi:10.1016/s0140-6736(89)91258-0 - Pubmed
- 2. Michael S. Hofman, W. F. Eddie Lau, Rodney J. Hicks. Somatostatin Receptor Imaging with 68Ga DOTATATE PET/CT: Clinical Utility, Normal Patterns, Pearls, and Pitfalls in Interpretation. (2015) RadioGraphics. 35 (2): 500-16. doi:10.1148/rg.352140164 - Pubmed