Krenning score of neuroendocrine tumor uptake
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 SPECT/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, et al. Localisation of endocrine-related tumours with radioiodinated analogue of somatostatin. Lancet 1989;1(8632):242–244
- 2. Hofman MS, Lau WF, Hicks RJ. Somatostatin receptor imaging with 68Ga DOTATATE PET/CT: clinical utility, normal patterns, pearls, and pitfalls in interpretation. Radiographics. 2015;35:500–516.