The major pitfalls in MR imaging of knee are due to anatomic variants and artefacts, especially partial volume effects. ( 40 )
Understanding the basic MR imaging principles, applying the correct technique, knowing the normal anatomy and variants, recognizing artifacts, and assuring good clinical and radiographic correlation helps avoid these potential pitfalls. ( 41 )
MR IMAGING ARTIFACTS: They are defined as either any signal or void in the images that does not have an anatomic basis, or as the result of distortion, addition or deletion of information. ( 42 )
Depending on their origin, one can classify them into the following groups : ( 43 )
1- Truncation artifacts : Truncation or Gibbs artifacts are bright or dark lines that are seen parallel to edges …show more content…
( 20 ) o Posterior cruciate ligament :
Distinguishing mucoid degeneration of the PCL from a PCL tear can prove a diagnostic challenge because thickening and increased signal intensity of the PCL can also be seen with longitudinal interstitial tears. The tram-track appearanceof the PCL, manifested as homogeneous longitudinal increased intrasubstance signal intensity of the PCL bounded by well-defined intact rims of low signal intensity, has been described as a reliable MRI finding in mechanically stable PCLs with mucoid degeneration. ( 50 )
There are both normal anatomical and abnormal structures which can mimic the double PCL sign . These include meniscomeniscal ligaments, accessory mensicofemoral ligaments (ligament of Humphrey and Wrisberg), loose bodies, osteophytes and fracture fragments lying underneath the PCL. ( 51 )
o Anterior transverse intermeniscal ligament
Understanding the basic MR imaging principles, applying the correct technique, knowing the normal anatomy and variants, recognizing artifacts, and assuring good clinical and radiographic correlation helps avoid these potential pitfalls. ( 41 )
MR IMAGING ARTIFACTS: They are defined as either any signal or void in the images that does not have an anatomic basis, or as the result of distortion, addition or deletion of information. ( 42 )
Depending on their origin, one can classify them into the following groups : ( 43 )
1- Truncation artifacts : Truncation or Gibbs artifacts are bright or dark lines that are seen parallel to edges …show more content…
( 20 ) o Posterior cruciate ligament :
Distinguishing mucoid degeneration of the PCL from a PCL tear can prove a diagnostic challenge because thickening and increased signal intensity of the PCL can also be seen with longitudinal interstitial tears. The tram-track appearanceof the PCL, manifested as homogeneous longitudinal increased intrasubstance signal intensity of the PCL bounded by well-defined intact rims of low signal intensity, has been described as a reliable MRI finding in mechanically stable PCLs with mucoid degeneration. ( 50 )
There are both normal anatomical and abnormal structures which can mimic the double PCL sign . These include meniscomeniscal ligaments, accessory mensicofemoral ligaments (ligament of Humphrey and Wrisberg), loose bodies, osteophytes and fracture fragments lying underneath the PCL. ( 51 )
o Anterior transverse intermeniscal ligament