Nuklearmedizin 2019; 58(02): 123
DOI: 10.1055/s-0039-1683522
Vorträge
PET: FDG und neue Tracer
Georg Thieme Verlag KG Stuttgart · New York

Textural analysis of DOTATOC-PET/MRI and its association with histological grading in patients with liver metastases from neuroendocrine tumors

M Weber
1   Universitätsklinikum Essen, Klinik für Nuklearmedizin, Essen
,
C Rischpler
1   Universitätsklinikum Essen, Klinik für Nuklearmedizin, Essen
,
B Schaarschmidt
2   Universitätsklinikum Essen, Institut für Diagnostische und Interventionelle Radiologie und Neuroradiologie, Essen
,
WP Fendler
1   Universitätsklinikum Essen, Klinik für Nuklearmedizin, Essen
,
H Lahner
3   Universitätsklinikum Essen, Klinik für Endokrinologie, Essen
,
L Umutlu
2   Universitätsklinikum Essen, Institut für Diagnostische und Interventionelle Radiologie und Neuroradiologie, Essen
,
K Herrmann
1   Universitätsklinikum Essen, Klinik für Nuklearmedizin, Essen
› Author Affiliations
Further Information

Publication History

Publication Date:
27 March 2019 (online)

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Ziel/Aim:

Neuroendocrine tumors (NETs) are known to overexpress somatostatin receptors (SSTRs), which can be visualized by DOTATOC-PET. A reduced SSTR expression -resulting in a decreased DOTATOC uptake- on the other hand is believed to be indicative of dedifferentiation and higher proliferation. The aim of this retrospective study was to assess if conventional PET parameters and textural features (TF) derived from simultaneous PET and MRI incl. apparent diffusion coefficient (ADC) are associated with the proliferative activity of NETs, potentially allowing an accurate non-invasive tumor grading.

Methodik/Methods:

PET/MRI scans of 315 patients with NETs were screened and patients with liver metastases > 1 cm were then retrospectively analyzed. Apart from conventional PET parameters, such as maximum and mean standardized uptake value (SUVmax, SUVmean) and metabolic tumor volume (MTV) more elaborate TF parameters from PET and ADC MRI (incl. entropy, homogeneity) from up to 5 liver lesions per patient were assessed using LIFExsoft. Correlation between mitotic activity as measured by Ki67-/MIB1-index and the aforementioned parameters was analyzed by virtue of Pearson test.

Ergebnisse/Results:

98 patients were eligible for the study with a Ki67-index ranging from < 1% to 30%. A total of 353 liver lesions were analyzed. There was a statistically significant correlation between Ki-67 index on the one hand and conventional PET parameters, entropy, homogeneity of PET and ADC maps on the other hand. However, Pearson test showed only a weak association with r ranging from -0.04 to 0.24.

Schlussfolgerungen/Conclusions:

In our study cohort conventional PET parameters and TF of PET and ADC MRI showed only a weak correlation with Ki67. This indicates that in patients with a Ki67-index of up to 30% TF analysis of combined PET/MRI may not be reliably used for accurate non-invasive tumor grading. On the other hand, this indicates that PET should also be considered as a staging tool in higher grade NETs.