However, studies have shown that even CT underestimates the number of pulmonary metastases compared with lung palpation during thoracotomy. Specific to osteosarcoma pulmonary metastases, CT missed approximately 10% of palpable lung lesions, of which nearly half were confirmed metastases in a series of 118 patients with osteosarcoma [9]. A smaller series of 28 patients with osteosarcoma also showed that CT missed 26% of viable metastases compared with palpation [11]. However, as CT technology improves and slice thickness decreases, more and smaller pulmonary nodules can be identified resulting in the dilemma of increased false-positive rates. A study of 283 lung nodules in patients with osteosarcoma found a statistically significant cutoff of 6 mm to differentiate benign and malignant pulmonary nodules (specificity 89.8%) [9]. A study of 311 subcentimeter pulmonary nodules in 195 patients with soft tissue sarcoma found combining morphologic criteria, in addition to size criteria, helped differentiate benign and malignant pulmonary nodules, with round solid nodules >5 mm more likely to be malignant (76% P = . 002) and complex ground-glass nodules <5 mm more likely to be benign (84%, P < . 0001) [12]. Given the survival benefit of treating pulmonary metastases, if pulmonary nodules are identified on any other modality in patients with primary musculoskeletal sarcoma, CT chest is then often indicated for biopsy and/or pretreatment planning. FDG-PET/CT Whole Body A meta-analysis of FDG-PET/CT for the staging of patients with osteosarcoma demonstrated 81% combined sensitivity and 94% specificity for detection of lung metastases [6]. The superiority of PET when combined with CT has been established [13].
Malignant or Aggressive Primary Musculoskeletal Tumor Staging And Surveillance PCAs. However, studies have shown that even CT underestimates the number of pulmonary metastases compared with lung palpation during thoracotomy. Specific to osteosarcoma pulmonary metastases, CT missed approximately 10% of palpable lung lesions, of which nearly half were confirmed metastases in a series of 118 patients with osteosarcoma [9]. A smaller series of 28 patients with osteosarcoma also showed that CT missed 26% of viable metastases compared with palpation [11]. However, as CT technology improves and slice thickness decreases, more and smaller pulmonary nodules can be identified resulting in the dilemma of increased false-positive rates. A study of 283 lung nodules in patients with osteosarcoma found a statistically significant cutoff of 6 mm to differentiate benign and malignant pulmonary nodules (specificity 89.8%) [9]. A study of 311 subcentimeter pulmonary nodules in 195 patients with soft tissue sarcoma found combining morphologic criteria, in addition to size criteria, helped differentiate benign and malignant pulmonary nodules, with round solid nodules >5 mm more likely to be malignant (76% P = . 002) and complex ground-glass nodules <5 mm more likely to be benign (84%, P < . 0001) [12]. Given the survival benefit of treating pulmonary metastases, if pulmonary nodules are identified on any other modality in patients with primary musculoskeletal sarcoma, CT chest is then often indicated for biopsy and/or pretreatment planning. FDG-PET/CT Whole Body A meta-analysis of FDG-PET/CT for the staging of patients with osteosarcoma demonstrated 81% combined sensitivity and 94% specificity for detection of lung metastases [6]. The superiority of PET when combined with CT has been established [13].