Advertisement
-
1
Mengiardi B, Pfirrmann CWA: Magic angle effect in MR imaging of ankle tendons: influence of foot positioning on prevalence and site in asymptomatic subjects and cadaveric tendons. Eur Radiol 16: 2197, 2006.
-
2
Link SC, Erickson SJ, Timins ME: MR Imaging of the ankle and foot: normal structures and anatomic variants that may simulate disease. AJR Am J Roentgenol 161: 607, 1993.
-
3
Wang XT, Rosenberg ZS, Mechlin MB, et al: Normal variants and diseases of the peroneal tendons and superior peroneal retinaculum: MR imaging features. Radiographics 25: 587, 2005.
-
4
Srikhum W, Nardo L, Karampinos DC, et al: Magnetic resonance imaging of ankle tendon pathology: benefits of additional axial short-tau inversion recovery imaging to reduce magic angle effects. Skeletal Radiol 42: 499, 2013.
-
5
Helms C: Fundamentals of Skeletal Radiology, Elsevier Health Sciences, Philadelphia, 2005.
-
6
Rosenberg ZS, Beltran J, Bencardino JT: From the RSNA Refresher Courses: MR imaging of the ankle and foot. Radiographics 20: S153, 2000.
-
7
Park HJ, Lee So, Park NH: Accuracy of MR findings in characterizing peroneal tendons disorders in comparison with surgery. Acta Radiol 53: 795, 2012.
-
8
Erickson SJ, Cox IH, Hyde JS, et al: Effect of tendon orientation on MR imaging signal intensity: a manifestation of the “magic angle” phenomenon. Radiology 181: 389, 1991.
-
9
Cheung Y, Rosenberg ZS, Magee T, et al: Normal anatomy and pathologic conditions of ankle tendons: current imaging techniques. Radiographics 12: 429, 1992.
-
10
Klein MA: Reformatted three-dimensional Fourier transform gradient- recalled echo MR imaging of the ankle: spectrum of normal and abnormal findings. AJR Am J Roentgenol 161: 831, 1993.
-
11
Peh WCG, Chan JHM: The magic angle phenomenon in tendons: effect of varying the MR echo time. Br J Radiol 71: 31, 1998.
True Pathologic Abnormality versus Artifact
Foot Position and Magic Angle Artifact in the Peroneal Tendons with 3T Imaging
Magnetic resonance imaging is a commonly ordered examination by many foot and ankle surgeons for ankle pain and suspected peroneal tendon pathologic abnormalities. Magic angle artifact is one of the complexities associated with this imaging modality. Magic angle refers to the increased signal on magnetic resonance images associated with the highly organized collagen fibers in tendons and ligaments when they are orientated at a 55° angle to the main magnetic field. We present several examples from a clinical practice setting using 3T imaging illustrating a substantial reduction in magic angle artifact of the peroneal tendon in the prone plantarflexed position compared with the standard neutral (right angle) position.
