ObjectiveThe aims of this study were to assess the sensitivity of various magnetic resonance imaging (MRI) sequences for the diagnosis of pulmonary nodules and to estimate the accuracy of MRI for the measurement of lesion size, as compared to computed tomography (CT).MethodsFifty patients with 113 pulmonary nodules diagnosed by CT underwent lung MRI and CT. MRI studies were performed on 1.5T scanner using the following sequences: T2-TSE, T2-SPIR, T2-STIR, T2-HASTE, T1-VIBE, and T1-out-of-phase. CT and MRI data were analyzed independently by two radiologists.ResultsThe overall sensitivity of MRI for the detection of pulmonary nodules was 80.5% and according to nodule size: 57.1% for nodules ≤4mm, 75% for nodules >4-6mm, 87.5% for nodules >6-8mm and 100% for nodules >8mm. MRI sequences yielded following sensitivities: 69% (T1-VIBE), 54.9% (T2-SPIR), 48.7% (T2-TSE), 48.7% (T1-out-of-phase), 45.1% (T2-STIR), 25.7% (T2-HASTE), respectively. There was very strong agreement between the maximum diameter of pulmonary nodules measured by CT and MRI (mean difference -0.02 mm; 95% CI –1.6–1.57 mm; Bland-Altman analysis).ConclusionsMRI yielded high sensitivity for the detection of pulmonary nodules and enabled accurate assessment of their diameter. Therefore it may be considered an alternative to CT for follow-up of some lung lesions. However, due to significant number of false positive diagnoses, it is not ready to replace CT as a tool for lung nodule detection.

BACKGROUND: Airway remodeling in asthma and COPD results in bronchial wall thickening. The thickness of the bronchial wall can be measured in high-resolution computed tomography. The objectives of the study were to assess the bronchial lumen and wall dimensions in asthma and COPD patients, in relation to disease severity, and to compare the airway dimensions in patients with asthma and COPD. METHODS: Ten asthma subjects and 12 COPD subjects with stable, mild to moderate disease were investigated. All subjects underwent chest high-resolution computed tomography (window level ؊ 450 Hounsfield units, window width 1,500 Hounsfield units). Cross-sections of bronchi (external diameter 1.0 -5.0 mm) were identified on enlarged images. The following variables were measured: external and internal diameter, wall area, lumen area, total airway area, the percentage of airway wall area, wall thickness, and the ratio of wall thickness to external diameter. Separate sub-analyses were performed for airways with external diameter < 2.0 mm and external diameter > 2.0 mm. RESULTS: We measured 261 and 348 cross-sections of small airways in subjects with asthma and COPD, respectively. There was a significant difference in wall thickness and wall area, which were both greater in asthmatics than in COPD patients. In bronchi with external diameter > 2.0 mm, all measured parameters were significantly higher in asthma than COPD. In individual asthmatics the airway wall thickness was similar in all the assessed bronchi, while in COPD it was related to the external airway diameter. CONCLUSIONS: Our results indicate that bronchial walls are thicker in asthmatics than in patients with COPD. It seems that airway wall thickness and the lumen diameter in patients with asthma are related to disease severity. There is no such a relationship in COPD patients. High-resolution computed tomography may be a useful tool in the assessment of airway structure in obstructive lung disease.

Contrast-enhanced computed tomography (CECT) and positron emission tomography with 18-FDG (FDG-PET/CT) are used to identify malignant solitary pulmonary nodules. The aim of the study was to evaluate the accuracy of CECT and FDG-PET/CT in diagnosing the etiology of solitary pulmonary nodule (SPN).Eighty patients with newly diagnosed SPN >8 mm were enrolled. The patients were scheduled for either or both, CECT and FDG-PET/CT. The nature of SPN (malignant or benign) was determined either by its pathological examination or radiological criteria.In 71 patients, the etiology of SPN was established and these patients were included in the final analysis. The median SPN diameter in these patients was 13 mm (range 8–30 mm). Twenty-two nodules (31%) were malignant, whereas 49 nodules were benign.FDG-PET/CT was performed in 40 patients, and CECT in 39 subjects. Diagnostic accuracy of CECT was 0.58 (95% confidence interval [CI] 0.41–0.74). The optimal cutoff level discriminating between malignant and benign SPN was an enhancement value of 19 Hounsfield units, for which the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of CECT were 100%, 37%, 32%, and 100%, respectively. Diagnostic accuracy of FDG-PET/CT reached 0.9 (95% CI 0.76–0.9). The optimal cutoff level for FDG-PET/CT was maximal standardized uptake value (SUV max) 2.1. At this point, the sensitivity, specificity, PPV, and NPV were 77%, 92%, 83%, and 89%, respectively.The diagnostic accuracy of FDG-PET/CT is higher than that of CECT. The advantage of CECT is its high sensitivity and negative predictive value.