MRI offers high-resolution assessment of carpal tunnel syndrome, showing median nerve enlargement, signal changes, and flexor retinaculum bowing. It identifies soft-tissue abnormalities, secondary causes, and postoperative complications. While superior for complex or recurrent cases and surgical planning, MRI is costly, less accessible, and not routinely required compared to clinical or electrodiagnostic evaluation.

Magnetic resonance imaging (MRI) provides high-resolution multiplanar visualization of the carpal tunnel and surrounding structures, making it a valuable, though not first-line, modality in the evaluation of CTS. It is generally reserved for atypical, severe, or recurrent cases, or when secondary causes of compression are suspected.

• • Key Applications:

==Median nerve assessment==:

Enlargement and increased signal intensity of the median nerve on T2-weighted or STIR sequences.

Flattening of the nerve distal to the site of compression.

“Bow sign” of the flexor retinaculum, reflecting increased pressure within the tunnel.

Surrounding soft tissues:

Detection of synovitis, flexor tenosynovitis, anomalous muscles, or ganglion cysts contributing to nerve compression.

Secondary and systemic causes:

Demonstrates space-occupying lesions, tumors, or infiltrative diseases (e.g., amyloidosis, gout, rheumatoid arthritis).

Postoperative evaluation:

Helpful in assessing incomplete release, scar tissue, or recurrent CTS.

• • Advantages:

Superior soft-tissue resolution compared to ultrasound or CT.

Comprehensive evaluation of both nerve and adjacent structures.

Useful for surgical planning in complex or recurrent CTS.

• • Limitations:

More expensive and less accessible than ultrasound.

Not routinely required for diagnosis, as clinical assessment and nerve conduction studies remain the gold standard.

Static imaging; less effective in assessing nerve mobility compared to ultrasound.