MR Scan: Understanding Magnetic Resonance Imaging (MRI)

MR stands for Magnetic Resonance. An MR scan (commonly called MRI – Magnetic Resonance Imaging) is a non-invasive medical imaging technique.

How It Works

• Uses a strong magnetic field (1.5T–3T typical) to align hydrogen protons in body tissues.
• Radiofrequency pulses perturb this alignment.
• As protons relax, they emit signals detected by coils.
• Computer reconstructs detailed cross-sectional images based on tissue proton density and relaxation times (T1, T2).

Key Advantages

• No ionizing radiation (safe for repeated use, pregnancy).
• Superior soft tissue contrast (brain, spine, joints, organs).
• Multiplanar imaging (axial, sagittal, coronal, oblique).
• Functional MRI (fMRI), diffusion (DWI), perfusion, spectroscopy, angiography (MRA).

Common Indications

• Neurologic: stroke, MS, tumors, dementia, seizures.
• Musculoskeletal: ligament/meniscus tears, spinal discs, marrow edema.
• Abdominal/pelvic: liver, pancreas, uterus, prostate, rectal cancer staging.
• Cardiac: structure, function, viability, congenital disease.
• Breast: high-risk screening, implant evaluation.

Contraindications

Ferromagnetic implants (some pacemakers, cochlear implants, aneurysm clips), metallic foreign bodies in critical areas. Screening questionnaire mandatory.