Image Fusion
Applications of positron emission tomography/computed tomography image fusion in clinical positron emission tomography—clinical use, interpretation methods, diagnostic improvements☆,☆☆

https://doi.org/10.1053/snuc.2003.127312Get rights and content

Abstract

Positron emission tomography (PET)/computed tomography (CT) scanners with combined dedicated high performance PET and CT scanners have been introduced recently in PET imaging. Oncological imaging with fluorodeoxyglucose (FDG) is currently the dominant application of PET. The addition of CT to PET offers many advantages, including obtaining a fast and relatively low-noise transmission scan, shortening the duration of the examination, adding precise anatomical information to FDG imaging, and providing additional diagnostic information. However, the use of CT for attenuation correction can lead to some artifacts that need to be considered when interpreting a PET/CT study: quantitative measurements may be altered, high density IV and oral and metallic objects may produce artifacts, and the registration of PET and CT may occasionally be suboptimal. Areas where using PET/CT offers particular potential advantages include the head and neck region, abdomen, and pelvis. Even in the thorax, PET/CT offers some advantages. Although clinical data evaluating the added value of PET/CT over PET are presently limited, preliminary results are very encouraging. More studies are warranted to clearly define the clinical impact of PET/CT over PET; however, it is clear this dedicated fusion technology will be very important for patient imaging in the coming years. © 2003 Elsevier Inc. All rights reserved.

Section snippets

PET/CT: Technical aspects and their clinical implications

The addition of a CT scanner offers several advantages to PET imaging. The CT can be used to perform attenuation correction, to precisely localize radiotracer uptake, and to provide an additional anatomical diagnostic tool (CT) to the metabolic PET imaging.

PET/CT imaging: Clinical applications

As stated previously, in addition to attenuation correction, CT can be used for localization and diagnostic purposes. The published data are presently limited regarding the added value and clinical impact of PET/CT over “regular” PET.

In a retrospective review comparing PET and PET/CT in 32 patients with various proven or suspected cancers, PET/CT and PET gave comparable information in 18 patients.21 In 10 patients, PET/CT allowed correct characterization of physiological FDG uptake as benign.

Conclusion

The introduction of inline dedicated PET/CT scanners, combined with the rapid growth of the clinical use of PET imaging, has already led to an expanding role of PET/CT in oncologic imaging. This technology offers unique opportunities by combining two already excellent modalities, PET and CT scanning. A PET/CT study has the ability to provide a synergistic combination of PET and CT, which could potentially be more valuable than the two exams performed separately. PET/CT is still in its infancy,

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    Address reprint requests to Richard L. Wahl, MD, Division of Nuclear Medicine, the Johns Hopkins Hospital, The Russell H. Morgan Department of Radiology and Radiological Sciences, 601 N. Caroline Street, Room 3223, Baltimore, MD 21287-0817.

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    Copyright © 2003 Elsevier Inc. All rights reserved.