MR-Derived CT-Like Images and Simulated Radiographs versus Conventional Radiography in Patients with Benign and Malignant Bone Tumors

Introduction: Our aim was to evaluate the diagnostic value of magnetic resonance (MR)–derived computed tomography (CT)–like images and simulated radiographs compared with conventional radiographs in patients with benign or malignant bone tumors.

Material and Methods: In 32 patients with benign or malignant bone lesions (mean age: 33.9 ± 18.5 years; 17 women), 3-T MR imaging was performed including a three-dimensional T1-weighted gradient-echo sequence as the basis for the CT-like images. From these, intensity-inverted MR image volumes were converted into two-dimensional images via a forward projection to obtain simulated radiographs. Two radiologists assessed these images as well as conventional radiographs for type of periosteal reaction, matrix mineralization, and destruction pattern. Agreement between the modalities was calculated using Cohen’s κ.

Results: The agreement between conventional radiographs and MR-derived CT-like images in combination with simulated radiographs was substantial (periosteal reaction, κ = 0.67; destruction pattern, κ = 0.75), and the sensitivity of both modalities for the final diagnosis of the lesion (aggressive versus nonaggressive) was high (MR-derived CT-like images, 86.2% versus conventional radiographs, 90.0%). Additional information on soft tissue extension (MR-derived CT-like images, 21.9% versus conventional radiographs, 12.5%; p = 0.009) and lobulation (9.4% versus 0%; p < 0.001) was significantly more often found on MR-derived CT-like images compared with conventional radiographs.

Conclusion: The assessment of destruction patterns, periosteal reaction, and the distinction between aggressive and nonaggressive tumors was feasible using MR-derived CT-like images and simulated radiographs and is comparable with conventional radiographs. Moreover, MR-derived CT-like images provided additional information on soft tissue extension and tumor architecture.

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