ABSTRACT
Positron emission tomography [PET] has been utilized in numerous aspects of medicine since its introduction and development in 1970s. There has been a rapid improvement in imaging techniques and radiotracers in the last decade, which have enhanced the quality of PET in different biomedical research domains and patient care settings. In this editorial we will discuss applications of PET-computed tomography [CT]/magnetic resonance imaging [MRI] as well as other radiotracers in different variety of malignant and non-malignant diseases such as cardiovascular, central nervous system, inflammatory and systemic diseases and review new concepts applicable to this imaging modality
ABSTRACT
The aim of this study was to assess the diagnostic potential of [18]F-FDG Positron Emission Tomography imaging in the evaluation of patients with solitary pulmonary nodules, by comparing the diagnostic criteria in single time point imaging method to two different diagnostic criteria in dual-time-point imaging. This retrospective study was conducted in the Hospital of the University of Pennsylvania, and data was collected and analyzed in the period from September 2005 to March 2006, from the pooled hospital studies for the last eight years. Two hundred sixty five patients were included [161 men, 104 women, age range: 41-92 years]. All had solitary pulmonary nodules on computed tomography, and the diagnosis was confirmed by biopsy or by follow up computed tomography. All 265 patients underwent whole body FDG PET scan, and 255 of them had PET scan two time points. The maximum standardized uptake values of nodules were calculated for both time points. On single time point imaging we set the maximum standardized uptake value of 2.5 as a cutoff criterion for malignancy. On dual time point imaging, first criterion of malignancy was set as any increase in the maximum SUV from the first to second time point. The second criterion was set as either no change or increase in the maximum standardized uptake value between the two time points. Sensitivity, specificity and accuracy were calculated for the three methods by using the biopsy results and clinical follow up as gold standard. Biopsy and follow-up revealed 72 patients with malignant lung nodules, whereas 193 patients had benign nodules. Single time point imaging with a threshold maximum standardized uptake value of 2.5 had a sensitivity, specificity and accuracy of 63%, 92% and 85% respectively. On dual-time-point imaging, for the initial criterion for malignancy, the sensitivity, specificity and accuracy were 81%, 95% and 91% respectively. On dual time point imaging, for the second criterion for malignancy, the sensitivity, specificity and accuracy were 92%, 93%, and 92% respectively. Dual-time-point FDG PET imaging using both criteria has higher sensitivity, specificity and accuracy compared to single time imaging. Dual-time-point FDG PET imaging should be included in the clinical workup of patients with pulmonary nodule