Weighted Imaging and Proton Magnetic Resonance Spectroscopy Findings in Osteosarcoma Versus Normal Muscle

Objectives:

The goal of our study was to assess diffusion-weighted (DW) imaging and proton magnetic resonance (MR) spectroscopy findings in osteosarcoma versus normal muscle at 3 Tesla (3 T) MR system.

Patients and Methods:

Nineteen patients highly suspicious for osteosarcoma and 12 normal young healthy adults were enrolled in this study. Two patients were excluded from the study due to incompatible histopathologic results. DW imaging and multivoxel proton MR spectroscopy at 3 T were performed for all participants. Surgical biopsy and histopathological examination were done for every patient after imaging. SPSS 20 was used for statistical analysis.

Results:

The minimum apparent diffusion coefficient (ADC) value of osteosarcoma (0.88 ± 0.28) in this study confirms the significant restriction of this tumor against the dark background of normal muscle in high b-value images. Fourteen (82%) of the available 17 patients had ADC values ≤ 1 × 10^-3 mm²/s. The maximum choline/creatine (Cho/Cr) ratio of osteosarcoma (1.94 ± 1.12) was statistically higher than the normal muscle (1.34 ± 0.11). Receiver operating curve (ROC) analysis (the area under the curve = 0.7) indicated a maximum Cho/Cr ratio of 1.37 as the cut point between the normal muscle and osteosarcoma, with a sensitivity, specificity and accuracy of 58.8%, 83.3%, and 69%, respectively. All patients with Cho/Cr ratios more than the cut point had ADC values ≤ 1 × 10^-3 mm²/s and all patients with ADC values higher than 1 × 10^-3 mm²/s had Cho/Cr ratios ≤ 1.37.