From the Research
Interpreting an FDG PET whole body scan without a CT scan is not recommended due to significantly limited diagnostic accuracy, and should be avoided when possible. The lack of anatomical context provided by CT makes it challenging for radiologists to precisely localize abnormal metabolic activity, distinguish physiologic from pathologic uptake, and accurately measure lesion size 1. This limitation is particularly problematic in oncology, where precise tumor localization and characterization are essential for staging and treatment planning.
Key Challenges
- Detecting small lesions
- Characterizing incidental findings
- Performing attenuation correction, which can lead to image artifacts and quantification errors
- Distinguishing between benign and malignant lesions, as certain diseases other than cancer may show increased uptake 2
Importance of Combined PET/CT Imaging
The complementary nature of metabolic (PET) and anatomical (CT) information significantly enhances diagnostic confidence, reduces false positives and negatives, and provides comprehensive data for clinical decision-making 3, 4. When CT cannot be performed, correlation with recent alternative imaging studies like MRI should be sought to provide anatomical context for PET findings.
Clinical Implications
In clinical practice, the use of combined PET/CT imaging is strongly favored as the standard approach, especially in oncology, where accurate staging and treatment planning are crucial 1. The integration of metabolic and anatomical information enables improved accuracy and characterization of disease, providing important prognostic information that may confer a high management impact and enable better personalized patient care.