Recommendations for Optimal PET/CT and Reviewing Recommendations to Achieve Optimal Diagnostic Quality and Interpretation of Multimodality PET/CT of Liver
| Category | Recommendations |
|---|---|
| Scanner requirements | When hybrid PET/CT with CT in expiration breath-hold is needed, a fast CT scanner (i.e., more than dual slice) is preferable to avoid breath-hold compliance issues. |
| When hybrid PET/CT with fast CT is available, expiration breath-hold CT may be preferable over free-breathing CT (no missed lesions and no artifacts on CT, whereas image registration and artifacts are not worse than that in free breathing). | |
| When hybrid PET/CT with slow CT is available, the choice between expiration breath-hold and free-breathing CT (for nondiagnostic use) is unsettled and depends on personal preference (i.e., more serious registration errors with breath-hold CT but increased risk on missed lesions on free-breathing CT). | |
| PET/CT image acquisition | Patient motion during or between image acquisitions may be limited by instructions and fixation materials. |
| Both expiration breath-hold and free-breathing protocols imply a trade-off between PET image quality, CT image quality, and patient comfort, and selection of a technique can be based on personal preference. | |
| When expiration breath-hold is to be performed, rehearsal of breathing instructions is advised before actual scanning, to avoid serious misregistration and artifacts. Revert to free breathing when breath-hold fails during rehearsal. | |
| Performance of PET/CT with breath-hold CT may be improved by providing feedback about image registration errors to operating personnel. | |
| When reliable correlative imaging of PET and CT images without artifacts is needed on an incidental basis, software fusion of dedicated PET and diagnostic CT can still be considered. | |
| Reviewing PET/CT | Awareness of level of misregistration and attenuation-correction artifacts can be improved by systematic reviewing of all uncorrected PET, corrected PET, and CT images. |
| Uncorrected PET images may reveal small lesions that may be undetectable or misplaced on corrected PET images, in diaphragmatic area of liver and lower lung fields. | |
| Unexplained PET lesions that show no correlating abnormalities on CT (e.g., free breathing, noncontrast-enhanced or low-dose) may be resolved by correlation with separate diagnostic, contrast-enhanced CT images. |
Most recommendations will also apply to whole-body imaging with PET/CT.