Thus, the authors concluded that CT would not be a suitable alternative for MARS-MRI and another study such as US may be considered. CT is also less able to detect muscle atrophy. In comparison with MARS-MRI, CT demonstrated a high rate of false-negative examinations for identifying muscle atrophy (sensitivity of 81%, specificity of 37%) [134]. Although, Walde et al [126] demonstrated in a cadaver model that MRI could detect osteolysis with greater sensitivity than CT. Robinson et al [134] demonstrated a reduced sensitivity (27%) and specificity (1%) of MARS- MRI in comparison with CT-MAR for detecting osteolysis associated with painful MoM hip prostheses. MRI Hip MARS-MRI has been used as a reference standard for imaging of the soft tissues around prosthetic hips [134,139]. ARMD Pseudotumors: MRI allows demonstration, localization, measurement, follow-up, determination of solid or cystic composition, and classification of pseudotumors associated with ARMD [36]. Invasion of adjacent soft tissues, muscle atrophy, and tendon avulsions can also be assessed [36,40,131]. Mahajan et al [140] found a difference in the appearance of pseudotumors depending on the site of corrosion. The MoP group demonstrated the highest proportion of thick-walled cystic masses (56.7% in head-neck taper corrosion MoP and 46.5% in dual taper corrosion MoP versus 28.7% in MoM), whereas the MoM group had the highest proportion of thin-walled cystic masses [140]. Weber et al [141] found no significant difference between the MRI appearances of symptomatic and asymptomatic MoP ARMD. Several studies have compared MARS-MRI with surgically proven ARMD pseudotumors. Sensitivity ranged from 71% to 93.9%. Specificity ranged from 42.9% to 87% [39,40,66].
Imaging after Total Hip Arthroplasty PCAs. Thus, the authors concluded that CT would not be a suitable alternative for MARS-MRI and another study such as US may be considered. CT is also less able to detect muscle atrophy. In comparison with MARS-MRI, CT demonstrated a high rate of false-negative examinations for identifying muscle atrophy (sensitivity of 81%, specificity of 37%) [134]. Although, Walde et al [126] demonstrated in a cadaver model that MRI could detect osteolysis with greater sensitivity than CT. Robinson et al [134] demonstrated a reduced sensitivity (27%) and specificity (1%) of MARS- MRI in comparison with CT-MAR for detecting osteolysis associated with painful MoM hip prostheses. MRI Hip MARS-MRI has been used as a reference standard for imaging of the soft tissues around prosthetic hips [134,139]. ARMD Pseudotumors: MRI allows demonstration, localization, measurement, follow-up, determination of solid or cystic composition, and classification of pseudotumors associated with ARMD [36]. Invasion of adjacent soft tissues, muscle atrophy, and tendon avulsions can also be assessed [36,40,131]. Mahajan et al [140] found a difference in the appearance of pseudotumors depending on the site of corrosion. The MoP group demonstrated the highest proportion of thick-walled cystic masses (56.7% in head-neck taper corrosion MoP and 46.5% in dual taper corrosion MoP versus 28.7% in MoM), whereas the MoM group had the highest proportion of thin-walled cystic masses [140]. Weber et al [141] found no significant difference between the MRI appearances of symptomatic and asymptomatic MoP ARMD. Several studies have compared MARS-MRI with surgically proven ARMD pseudotumors. Sensitivity ranged from 71% to 93.9%. Specificity ranged from 42.9% to 87% [39,40,66].