Diffusion-weighted MRI and in-phase/opposed-phase sequences in the assessment of bone tumors

Purpose: To evaluate the role of diffusion-weighted apparent diffusion coefficient (ADC) and in-phase/opposed-phase sequences in the differentiation of benign and malignant osseous tumors. Materials and Methods: At 1.5T, routine sequences were compared to diffusion-weighted and in-phase/opposed-phase in 63 patients. Routine sequence magnetic resonance imaging (MRI) scoring, mean ADC value, and in-phase/opposed-phase signal intensity ratio (SIR) was obtained. Statistical analysis included significance, receiver operating characteristic (ROC), and linear correlation between the three parameters. Results: In all, 38 patients had malignant tumors and 25 patients had benign tumors. Benign and malignant tumors showed different routine sequence scores (P < 0.001). Mean ADC of the benign lesions ranged 0.9–3.2 × 10−3mm2/sec of mean ± SD (1.9 ± 0.6). In malignant tumors, the mean ADC ranged 0.6–1.9 × 10−3mm2/sec of mean ± SD (1.1 ± 0.4) (P < 0.0001). There was a possible differentiation between malignant and benign tumors at a threshold of 1.1 × 10−3mm2/sec of sensitivity and specificity of 94.1% and 70.3%, respectively. SIR for benign tumors ranged 0.2–1.0 of mean ± SD (0.6 ± 0.3). For malignant lesions SIR ranged 0.4–1.2 of mean ± SD (0.8 ± 0.3). Benign and malignant tumors show statistically significant SIR at P < 0.022 with possible differentiation at a threshold of 0.75 of sensitivity and specificity of 70.3% and 76.5%, respectively. Simple linear correlation between both ADC and SIR was significant at P < 0.01 with correlation coefficient (r) = 0.45. Conclusion: Diffusion-weighted and in-phase/opposed-phase imaging might be used in addition to conventional MRI as a routine tool for differentiation of benign and malignant tumors. J. Magn. Reson. Imaging 2016;44:565–572.