Role of delayed phase contrast-enhanced CT in the intra-thoracic staging of non-small cell lung cancer (NSCLC): What does it add?

PURPOSE: The aim of the study was to investigate differences in non-small cell lung cancer (NSCLC) intra-thoracic staging by using contrast-enhanced computed tomography (ce-CT) at the arterial phase (AP), at the arterial plus delayed phases (AP + DEP), and at the delayed phase (DEP), and to evaluate their potential impact on disease staging. MATERIALS AND METHODS: Two chest radiologists with different level of expertise and a general radiologist independently reviewed the chest CT exams of 150 patients with NSCLC; CT scans were performed 40 s (AP) and 60 s (DEP) after contrast material injection. Image assessment included three reading sessions: session A (AP), session B (AP + DEP) and session C (DEP). CT descriptors for the primary tumour (T), regional nodal involvement (N), and intra-thoracic metastases (M) were evaluated in each reading session. Readers had to assign a confidence level (CL) for the assessment of each descriptor and define the TNM stage. Friedman and Cochran Q test was used to compare the assessments of the 3 reading sessions; inter-reader agreement was determined (Intraclass Correlation Coefficient - ICC). RESULTS: The CL was significantly higher in sessions B and C than in session A for all descriptors, with the exception of pulmonary arterial invasion. Primary tumour inner necrosis and regional nodal involvement were detected in a significantly higher number of cases in sessions B and C as compared to session A (p ≤ 0.001). DEP significantly changed N stage determination (p < 0.001), particularly N3, and excluded chest wall invasion (p = 0.05) and venous invasion (p = 0.001). The agreement was good among the 3 readers (ICC = 0.761) and excellent between the 2 chest radiologists (ICC ≥ 0.940), regardless of the contrast phase. CONCLUSIONS: The 60-second DEP ce-CT for staging NSCLC significantly increased the readers' CL, changed the N stage determination, and helped excluding chest wall invasion and venous invasion.

The added value of chemical shift MRI in the preoperative diagnosis of thymolipoma.

Thymolipoma is a rare tumor of the thymus. Classic radiologic findings of thymolipoma include fatty masses of the anterior mediastinum in conjunction with the thymus. Differential diagnosis with other more aggressive entities like liposarcoma and teratoma can be challenging. We report a case where chemical shift magnetic resonance imaging helped in the differential diagnosis.

Multifunctional Assessment of Non-Small Cell Lung Cancer: Perfusion-Metabolic Correlation.

PURPOSE: The aim of this study was to investigate the relationship between whole-tumor CT perfusion and FDG PET/CT parameters in non-small cell lung cancer (NSCLC). METHODS: Twenty-five patients with NSCLC were prospectively included. CT perfusion parameters calculated were blood flow (BF), blood volume (BV), mean transit time, and peak enhancement intensity. SUVmax, SUVpeak, SUVmean, metabolic tumor volume (MTV), and total lesion glycolysis (TLG) were evaluated for PET/CT. Tumor diameter and volume were measured, and lesions were divided according to maximum axial diameter in more than 3 cm and 3 cm or less. The correlations between CT perfusion and PET/CT parameters were assessed in all tumors, as well as according to tumor diameter and volume. RESULTS: Lesion diameter and volume showed a negative correlation with BF and BV (r = -0.78, -0.78, -0.57, -0.48, respectively) and a positive correlation with mean transit time (r = 0.55, 0.65, respectively). The negative correlation between BF and lesion diameter and volume was confirmed in the subgroup of lesions of more than 3 cm (r = -0.68, -0.68, respectively). A positive correlation between SUVmax, SUVpeak, SUVmean, and lesion volume was observed (r = 0.50, 0.50, 0.46, respectively) and confirmed in lesions 3 cm or less (r = 0.81, 0.79, 0.78, respectively). Metabolic tumor volume and TLG showed a positive correlation with lesion diameter and volume in the overall population (r = 0.93, 0.87, 0.88, 0.90, respectively) and in lesions of more than 3 cm (r = 0.89, 0.84, 0.84, 0.79, respectively). Blood flow and BV showed a negative correlation with MTV and TLG (r = -0.77, -0.74, and -0.58, -0.48, respectively) in the overall population and with MTV in lesions of more than 3 cm (r = -0.69, -0.62, respectively). CONCLUSIONS: Perfusion and metabolic parameters seem to depend on tumor size. The bigger the tumor, the lower the BF and the BV and, conversely, the higher the SUVpeak, MTV, and TLG. This information would be useful in the clinical setting when diagnosing or treating NSCLC, especially with novel therapies and/or for radiation treatment modulation.