PET/CT with intravenous contrast can be used for PET attenuation correction in cancer patients

Research output: Contribution to journalJournal articleResearchpeer-review

A K Berthelsen, S Holm, A Loft, T L Klausen, F Andersen, L Højgaard

PURPOSE: If the CT scan of a combined PET/CT study is performed as a full diagnostic quality CT scan including intravenous (IV) contrast agent, the quality of the joint PET/CT procedure is improved and a separate diagnostic CT scan can be avoided. CT with IV contrast can be used for PET attenuation correction, but this may result in a bias in the attenuation factors. The clinical significance of this bias has not been established. Our aim was to perform a prospective clinical study where each patient had CT performed with and without IV contrast agent to establish whether PET/CT with IV contrast can be used for PET attenuation without reducing the clinical value of the PET scan.

METHODS: A uniform phantom study was used to document that the PET acquisition itself is not significantly influenced by the presence of IV contrast medium. Then, 19 patients referred to PET/CT with IV contrast underwent CT scans without, and then with contrast agent, followed by an 18F-fluorodeoxyglucose whole-body PET scan. The CT examinations were performed with identical parameters on a GE Discovery LS scanner. The PET data were reconstructed with attenuation correction based on the two CT data sets. A global comparison of standard uptake value (SUV) was performed, and SUVs in tumour, in non-tumour tissue and in the subclavian vein were calculated. Clinical evaluation of the number and location of lesions on all PET/CT scans was performed twice, blinded and in a different random order, by two independent nuclear medicine specialists.

RESULTS: In all patients, the measured global SUV of PET images based on CT with IV contrast agent was higher than the global activity using non-contrast correction. The overall increase in the mean SUV (for two different conversion tables tested) was 4.5+/-2.3% and 1.6+/-0.5%, respectively. In 11/19 patients, focal uptake was identified corresponding to malignant tumours. Eight out of 11 tumours showed an increased SUVmax (2.9+/-3.1%) on the PET images reconstructed using IV contrast. The clinical evaluation performed by the two specialists comparing contrast and non-contrast CT attenuated PET images showed weighted kappa values of 0.92 (doctor A) and 0.82 (doctor B). No contrast-introduced artefacts were found.

CONCLUSION: This study demonstrates that CT scans with IV contrast agent can be used for attenuation correction of the PET data in combined modality PET/CT scanning, without changing the clinical diagnostic interpretation.

Original languageEnglish
JournalEuropean Journal of Nuclear Medicine and Molecular Imaging
Volume32
Issue number10
Pages (from-to)1167-75
Number of pages9
ISSN1619-7070
DOIs
Publication statusPublished - Oct 2005

    Research areas

  • Adult, Aged, Artifacts, Contrast Media, Female, Fluorodeoxyglucose F18, Humans, Image Enhancement, Injections, Intravenous, Iothalamic Acid, Male, Middle Aged, Neoplasms, Phantoms, Imaging, Positron-Emission Tomography, Radiopharmaceuticals, Reproducibility of Results, Sensitivity and Specificity, Single-Blind Method, Subtraction Technique, Tomography, X-Ray Computed, Journal Article, Randomized Controlled Trial

ID: 165882182