PET-CT and diagnostic CT: the synergy of metabolic and morphological data in onco-haematology.

PURPOSE: Our goal was to determine how interpreting diagnostic CT together with PET-CT could improve the assessment of morphology in onco-haematology.

PATIENTS AND METHODS: Fifty-nine patients with aggressive lymphoma were retrospectively included. The diagnostic CT scan was interpreted by two radiologists, followed by a combined analysis of the CT and the PET-CT carried out by two specialists in metabolic and morphological imaging. The diagnostic performances were assessed in terms of sensitivity and specificity, then concordance and discordance rates (kappa) were studied.

RESULTS: A combined interpretation of CT and PET-CT showed better diagnostic performances than those of interpretations of CT only in the assessment of nodal sites (826 sites, sensitivity of 99% versus 85%, P<0.05), extranodal sites (649 sites, sensitivity of 88% versus 78%) and bone sites (one analysed per patient, sensitivity of 50% versus 27%). The combined interpretation also improved inter-observer agreement and led to an upgraded Ann Arbor staging in 15% of patients, with a change of treatment in 10%.

CONCLUSION: Interpretation of diagnostic CT in onco-haematology can be improved by combining it with an assessment of PET-CT. The synergy between metabolic and morphological information leads to improved diagnostic capabilities and renders interpretations more reproducible.