[Magnetic resonance in thoracic pathology: characterization by intensity values]

The authors examined prospectively 100 patients with lung diseases--50 of them benign and 50 malignant. The mean value of all lesions was measured with a constant region of interest (ROI); the muscle was considered as the reference tissue. Histopathology was the gold standard for the patients who underwent CT-guided needle biopsy and/or surgery; clinical-radiologic follow-up (average time: 2 years) was the gold standard for nonsurgical patients. A superconductive 1.5-T magnet with circular polarization body coil was used; T1- and T2-weighted spin echo images were acquired on the coronal and axial planes, respectively. The mean values with the constant ROI were measured both on the lesions and on the reference tissue to calculate and compare the T1-lesion/T1-muscle and T2-lesion/T2-muscle ratios in benign and malignant conditions. The t-test, the linear regression and correlation test and the analysis of variance were used to analyze the data. T1 benign lung disease/T1 muscle ratio was 1.21, while T1 malignant lung disease/T1 muscle ratio was 1.27, with no statistically significant difference. T2 benign lung disease/T2 muscle ratio was 2.63, while T2 malignant lung disease/T2 muscle ratio was 4.80: the difference was statistically significant (p < 0.001). To conclude, in chest diseases, the measurement of mean values in T2 allowed malignancy-indicative values (> 4 ratio) and positively benign values (< 2.5 ratio) to be identified.