Value of contrast-enhanced multi-phase CT in combined PET/CT protocols for oncological imaging.

Value of contrast-enhanced multi-phase CT in combined PET/CT protocols for oncological imaging.

Br J Radiol. 2007 Feb 28
Pfannenberg A.C., Aschoff P., Brechtel K., Muller M., Klein M., Bares R., Claussen C.D., Eschmann S.M.

Departments of Diagnostic Radiology, Eberhard-Karls-University Tuebingen, Hoppe-Seyler-Strasse 3, 72076 Tuebingen, Germany.
To evaluate the additional value of contrast-enhanced multi-phase CT in comparison with low-dose non-contrast CT in combined PET/CT protocols for oncological imaging we retrospectively analysed 100 patients with different malignant tumours. All patients underwent a PET/CT consisting of a multi-phase CT protocol including a low-dose non-enhanced attenuation scan and an arterial and portal-venous contrast-enhanced scan followed by a whole-body PET. PET/CT studies were analysed by different categories to determine the added value of contrast-enhanced CT. The additional value was defined as new information provided by diagnostic CT and not available by the low-dose CT, resulting in change of PET/CT interpretation. The results were validated either by histopathology or by clinical-radiological follow-up >/=6 months. The clinical impact was evaluated with respect to changes in patient management. Diagnostic multi-phase CT was of additional value in 52 out of 100 patients with 85 suspected lesions. In 40 out of 100 patients no additional value could be detected. Eight patients were excluded due to inconclusive diagnosis in both methods including fusion. The analysis showed the greatest benefit of diagnostic CT in the categories localization of pathological FDG uptake and precise tumour delineation, changing PET/CT interpretation in 42% and 31% of patients, respectively. The benefit of diagnostic CT was influenced by the tumour type demonstrating the highest impact in gastrointestinal, lung and neuroendocrine tumours. Diagnostic CT changed clinical management in 21 patients (21%). Diagnostic multi-phase CT as part of the combined PET/CT protocol has the potential to provide considerable additional value in specific clinical conditions with resultant change of management in a substantial proportion of patients.