krenning score krenning score the krenning score is used to grade the uptake intensity of neuroendocrine tumors on somatostatin receptor imaging such as octreotide scan. typically, peptide receptor radionuclide therapy (prrt) is considered when the krenning score is greater than 2. krenning scorepurposegrade uptake intensity of neuroendocrine tumors krenning score grade 1: uptake < normal liver grade 2: uptake = normal liver grade 3: uptake > normal liver grade 4: uptake > spleen or kidneys