MRI Scan Cartilage Mapping And Plantar Instability Parameters

MRI parameters include magnetic field strength (typically 0.5–3.0 Tesla, sometimes higher), pulse sequences (T1, T2, FLAIR, DWI), repetition time (TR) and echo time (TE), slice thickness and gap, field of view (FOV), matrix size/resolution, number of excitations (NEX), gradient strength and slew rate, acquisition time, and use of contrast agents (gadolinium) and specific receiver coils.

Typical knee MRI protocol: 1.5T–3T scanner, dedicated knee coil; planes: sagittal, coronal, axial; sequences: PD-weighted with/without fat suppression, T2-weighted, T1-weighted; slice thickness 3–4 mm with 0.3–0.5 mm gap; field of view 12–16 cm; matrix ~256×256; optional contrast (gadolinium) for infection/tumor or MR arthrography for cartilage/labral evaluation. Coverage includes patellofemoral joint and cruciate ligaments; acquisition time ~20–30 minutes.

Yes. MRI is the preferred noninvasive test to visualize cartilage and can identify tears, focal defects, thinning, and degenerative changes. Standard MRI shows structural damage; advanced techniques (T2 mapping, T1ρ, dGEMRIC) can detect early compositional changes before visible wear. Small superficial lesions may be missed, and arthroscopy remains the diagnostic gold standard when exact assessment or treatment is needed.

For morphological cartilage imaging, 3D proton-density–weighted sequences with fat suppression and high-resolution spoiled/gradient-echo techniques (e.g., DESS/SPGR) provide the best delineation and isotropic reformatting. For biochemical or early degenerative assessment, quantitative sequences such as T2 mapping and T1ρ detect collagen and proteoglycan changes. Routine knee protocols typically combine PD-FS or DESS plus a quantitative map for cartilage evaluation.

Factors affecting MRI image quality include magnetic field strength (B0) and homogeneity, coil type and placement, signal-to-noise ratio (SNR), spatial and contrast resolution (voxel size, slice thickness), sequence parameters (TR, TE, flip angle, bandwidth), gradient strength and slew rate, motion and physiological artifacts, acquisition time and acceleration techniques, and patient factors (movement, implants, body habitus).

A normal MRI report states no acute or chronic abnormalities, with normal anatomy and expected signal of the organ or region scanned. It notes no masses, hemorrhage, infarct, inflammation, demyelination, or structural lesions; normal-size ventricles, joints, ligaments or discs as relevant; and no compression or herniation. It may add “no contrast-enhancing lesions” and compare to prior studies if available.