Osteosarcoma subtypes: Magnetic resonance and quantitative diffusion weighted imaging criteria.

Area of Science:

• Oncology
• Radiology
• Medical Imaging

Background:

• Osteosarcoma (OS) is a primary bone cancer characterized by malignant spindle cells that produce osteoid.
• Understanding the imaging features of different OS subtypes is crucial for accurate diagnosis and treatment planning.

Purpose of the Study:

• To characterize the magnetic resonance imaging (MRI) features of various osteosarcoma subtypes.
• To determine the apparent diffusion coefficient (ADC) values for different OS subtypes.
• To investigate the relationship between the pathologic basis of OS subtypes and their corresponding ADC values.

Main Methods:

• A retrospective observational analysis of 31 pathologically confirmed osteosarcoma subtypes was conducted.
• Conventional MRI features, including bone of origin, intra-articular extension, invasion, pathological fractures, ossified matrix, hemorrhage, and necrosis, were recorded.
• Mean ADC values were measured for each osteosarcoma lesion.

Main Results:

• The femur was the most common origin (51.6%), with frequent intra-articular extension (29%) and distant metastases (25.8%).
• MRI revealed ossified matrix in all lesions, with hemorrhage (35.5%) and necrosis (58%) also observed.
• Mean ADC values ranged from 0.74 × 10⁻³ mm²/s (osteoblastic OS) to 1.50 × 10⁻³ mm²/s (telangiectatic OS), with an average of 1.16 ± 0.18 × 10⁻³ mm²/s.

Conclusions:

• Osteosarcoma exhibits diverse subtypes with distinct imaging criteria on MRI.
• Apparent diffusion coefficient (ADC) values vary significantly among osteosarcoma subtypes.
• The correlation between MRI features, ADC values, and pathologic subtypes aids in differentiating osteosarcoma.