How I Do It: MRI of the Bone with Marrow-specific Sequences

Area of Science:

• Radiology
• Medical Imaging
• Hematology

Background:

• Normal bone marrow consists of active red marrow and inactive yellow marrow.
• Bone marrow composition changes predictably with age and can undergo reconversion due to physiological stressors.
• Distinguishing normal marrow variations from pathological conditions can be challenging in routine practice.

Purpose of the Study:

• To provide a systematic approach for evaluating bone marrow on routine MRI.
• To highlight the utility of noncontrast MRI sequences for characterizing bone marrow signal.
• To aid in differentiating normal marrow conversion/reconversion from true bone marrow abnormalities.

Main Methods:

• Review of MRI appearance of normal bone marrow across different age groups.
• Emphasis on noncontrast "marrow-specific" MRI sequences.
• Discussion of T1-weighted spin-echo, chemical shift, and diffusion-weighted imaging (DWI) with apparent diffusion coefficient (ADC) mapping.

Main Results:

• Normal bone marrow exhibits age-dependent changes in signal intensity on MRI.
• Physiological red marrow reconversion can mimic pathological processes.
• Specific noncontrast MRI sequences are effective in characterizing focal or diffuse marrow abnormalities.

Conclusions:

• A systematic MRI approach using noncontrast sequences aids in accurate bone marrow evaluation.
• Understanding normal marrow conversion and reconversion is crucial for accurate diagnosis.
• MRI plays a vital role in differentiating normal marrow findings from true bone marrow pathology.