Effective methods to correct contrast agent-induced errors in PET quantification in cardiac PET/CT.
J Nucl Med
; 48(7): 1060-8, 2007 Jul.
Article
em En
| MEDLINE
| ID: mdl-17574981
ABSTRACT
UNLABELLED In combined PET/CT studies, x-ray attenuation information from the CT scan is generally used for PET attenuation correction. Iodine-containing contrast agents may induce artifacts in the CT-generated attenuation map and lead to an erroneous radioactivity distribution on the corrected PET images. This study evaluated 2 methods of thresholding the CT data to correct these contrast agent-related artifacts. METHODS:
PET emission and attenuation data (acquired with and without a contrast agent) were simulated using a cardiac torso software phantom and were obtained from patients. Seven patients with known coronary artery disease underwent 2 electrocardiography-gated CT scans of the heart, the first without a contrast agent and the second with intravenous injection of an iodine-containing contrast agent. A 20-min PET scan (single bed position) covering the same axial range as the CT scans was then obtained 1 h after intravenous injection of (18)F-FDG. For both the simulated data and the patient data, the unenhanced and contrast-enhanced attenuation datasets were used for attenuation correction of the PET data. Additionally, 2 threshold methods (one requiring user interaction) aimed at compensating for the effect of the contrast agent were applied to the contrast-enhanced attenuation data before PET attenuation correction. All PET images were compared by quantitative analysis.RESULTS:
Regional radioactivity values in the heart were overestimated when the contrast-enhanced data were used for attenuation correction. For patients, the mean decrease in the left ventricular wall was 23%. Use of either of the proposed compensation methods reduced the quantification error to less than 5%. The required time for postprocessing was minimal for the user-independent method.CONCLUSION:
The use of contrast-enhanced CT images for attenuation correction in cardiac PET/CT significantly impairs PET quantification of tracer uptake. The proposed CT correction methods markedly reduced these artifacts; additionally, the user-independent method was time-efficient.
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Bases de dados:
MEDLINE
Assunto principal:
Doença da Artéria Coronariana
/
Artefatos
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Imagens de Fantasmas
/
Meios de Contraste
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Fluordesoxiglucose F18
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Coração
Limite:
Humans
Idioma:
En
Revista:
J Nucl Med
Ano de publicação:
2007
Tipo de documento:
Article
País de afiliação:
Alemanha