Additional value of integrated PET-CT in the detection and characterization of lung metastases: correlation with CT alone and PET alone

Abstract

The purpose was evaluating retrospectively the additional value of integrated positron emission tomography (PET) and computed tomography (CT) in the detection of pulmonary metastases in comparison with CT and PET alone. Fifty-six lung nodules, divided into three groups according their size, detected in 24 consecutive patients with a known primary tumor were retrospectively evaluated with integrated PET-CT, CT and PET. The nature of these nodules was determined by either histopathology or a follow-up of at least 6 months. The CT and PET images of the integrated PET-CT were evaluated separately by a radiologist and a nuclear medicine physician, the integrated PET-CT images were evaluated by a chest radiologist and nuclear medicine physician in consensus. The investigators were asked to search lung nodules and to determine whether these nodules were metastases or not. Sensitivity and accuracy for CT, PET and integrated PET-CT for characterization of all pulmonary nodules were, respectively: 100%, 90%, 100% and 57%, 55%, 55%. There was no significant difference in the characterization of pulmonary nodules between integrated PET-CT and CT alone (P=1.000) and PET alone (P=0.1306). An accurate evaluation is only possible for lesions larger than 1 cm.

Significance of pulmonary nodules in patients with colorectal cancer

“…It is difficult to distinguish between metastatic and benign lesions, so additional diagnostic options such as PET/CT, percutaneous needle biopsy, or video-assisted thoracoscopic biopsy may prove helpful. Unfortunately, PET/CT can usually only detect nodules more than 10 mm in size [18]; percutaneous needle biopsy may be impossible or uninformative for the purposes of an accurate pathological diagnosis, depending on the size and site of nodules [31]; and video-assisted thoracoscopic biopsy is too invasive to be performed routinely [32]. Chest CT revealed growing nodules in a larger proportion of patients in our series (19/92; 20.6 %) than in other published studies, where the overall rate of ultimate diagnosis of malignancy ranged from 6.3 to 16.6 % in colorectal cancer patients found to have PNs [14,30,33].…”

“…The available studies concentrated on specific concerns, such as the utility of lower chest CT images [9], the significance of PNs in primary rectal cancer revealing positive local lymph nodes at histopathology [14], or the clinical relevance of PNs in patients undergoing resection surgery for colorectal cancer liver metastases [15]. Although CT is considered the most appropriate technique for detecting pulmonary metastases [16][17][18], an internationally shared consensus on the optimal imaging follow-up for colorectal cancer patients has yet to take shape. Practice guidelines on colorectal cancer surveillance after surgery recommend periodic chest CT [19][20][21].…”

The sensitivity of 18F-fluorodeoxyglucose positron emission tomography in the evaluation of metastatic pulmonary nodules☆

“…In another report, De Wever and colleagues found integrated FDG-PET/CT had a sensitivity of 100% compared to 83% for PET alone in nodules <10 mm, the majority of these nodules were 5-10 mm in diameter. In this particular study, the remarkably increased sensitivity came at the cost of a significant lowering of the specificity to only 5% [11].…”

Retrospective Study of 18F-FDG PET/CT in the Diagnosis of Inflammatory Breast Cancer: Preliminary Data

“…Therefore, 18 F-FDG PET is not routinely used in the staging work-up of patients with stage 1 or early stage 2 disease. To our knowledge, the role of 18 F-FDG PET/CT in staging IBC has been scarcely addressed in the medical literature (3), compared with staging of other diseases (18)(19)(20). The purpose of this retrospective study was to evaluate the accuracy of 18 F-FDG PET/CT in the initial staging of IBC.…”