Chemical shift imaging at 3 Tesla: effect of echo time on assessing bone marrow abnormalities

Area of Science:

• Radiology
• Oncology
• Medical Imaging

Background:

• Characterizing bone marrow signal changes in osteosarcoma is vital for diagnosis and treatment monitoring.
• In-phase (IP) and opposed-phase (OP) MRI sequences are commonly used, but their acquisition order may impact results.

Observation:

• This study evaluated the effect of varied IP and OP sequence order on characterizing marrow signal changes at 3T.
• Two acquisition methods were tested: OP before IP (approach 1) and OP after IP (approach 2).
• Signal intensity ratios (SIR) were measured in osteosarcoma and normal bone marrow locations.

Findings:

• Approach 1 (OP before IP) resulted in no false-negative interpretations of marrow replacement.
• Approach 2 (OP after IP) led to a high percentage of false-negative results (75%) due to susceptibility artifacts.
• Good interobserver agreement (CCC=0.96) was observed for signal intensity measurements.

Implications:

• Acquiring OP sequences prior to IP sequences at 3T MRI is recommended for accurate assessment of marrow signal abnormalities in osteosarcoma.
• Adhering to this sequence order can prevent erroneous interpretations and improve diagnostic confidence.
• This finding has direct clinical relevance for optimizing MRI protocols in oncologic imaging.