Magic angle artifact in MRI: how to recognise it and confirm it
A tendon that looks bright on a short-TE image is not always torn. The magic angle effect is the common mimic.
Magic angle
Bright signal inside a normal tendon or ligament on short-TE images (T1, PD, GRE; TE below about 32 ms), mimicking tendinosis or a tear.
Ordered collagen has a very short T2. When fibres lie at about 55° to B0, dipolar interactions vanish and T2 lengthens enough to give signal at short TE.
- Confirm on a T2-weighted sequence with a long TE: magic-angle signal disappears, pathology stays
- Reposition the joint to change the fibre angle
None. Typical sites: supraspinatus, peroneal tendons at the ankle, patellar tendon, triangular fibrocartilage.
This page is one entry from the MRI Technologist Reference
The full reference has 31 protocols, 9 dynamic study timelines, 19 artifacts, 16 scanner problems and 15 safety topics, as a PDF in English and Arabic plus an interactive tool.
Educational reference. It does not replace your site protocols, the radiologist's instructions, the MR safety officer, or the manufacturer's instructions for any implant, device or contrast agent. Parameter values are typical starting points at 1.5 T and must be adapted to the scanner, coil and patient.