Effect of tendon orientation on MR imaging signal intensity: a manifestation of the "magic angle" phenomenon. Radiology 1991 Nov;181(2):389-92
Date
11/01/1991Pubmed ID
1924777DOI
10.1148/radiology.181.2.1924777Scopus ID
2-s2.0-0026010198 (requires institutional sign-in at Scopus site) 277 CitationsAbstract
To determine whether orientation in the static field may be responsible for the frequent occurrence of increased signal intensity within normal tendons at magnetic resonance (MR) imaging, seven healthy volunteers were imaged by means of a 1.5-T unit and standard clinical pulse sequences. The wrist, ankle, and shoulder regions were evaluated with local coils. Imaging was performed with tendon orientations ranging from 0 degree to 90 degrees in relation to the constant magnetic induction field (B0). Markedly increased intratendinous signal intensity was observed at the "magic angle" of 55 degrees, intermediate signal intensity was observed at 45 degrees and 65 degrees, and no signal intensity was observed at 0 degree and 90 degrees. Signal intensity was evident only when a short echo time was used. The authors believe that tendon orientation greatly affects tendon signal intensity in vivo. Increased signal intensity due to the magic angle effect may be misdiagnosed as tendinous degeneration, tendinitis, or frank tear.
Author List
Erickson SJ, Cox IH, Hyde JS, Carrera GF, Strandt JA, Estkowski LDAuthors
Guillermo Carrera MD Emeritus Professor in the Radiology department at Medical College of WisconsinScott J. Erickson MD Professor in the Radiology department at Medical College of Wisconsin
MESH terms used to index this publication - Major topics in bold
Ankle JointArtifacts
Humans
Magnetic Resonance Imaging
Shoulder Joint
Tendons
Wrist Joint
