RT Book, Section
A1 Tehranzadeh, Arash David
A2 Tehranzadeh, Jamshid
SR Print(0)
ID 1127377496
T1 Knee MRI
T2 Basic Musculoskeletal Imaging
YR 2016
FD 2016
PB McGraw-Hill Education
PP New York, NY
SN 9780071787024
LK accessphysiotherapy.mhmedical.com/content.aspx?aid=1127377496
RD 2024/04/20
AB Magnetic  resonance  imaging  (MRI)  interpretation  of  the  knee  is  often  a  daunting  challenge  to  the  student  or  physician  in  training.  After  all,  an  entire  year  of  fellowship  training  is  dedicated  to  musculoskeletal  imaging.  To  overcome  this  challenge,  it  is  imperative  for  both  the  medical  student  and  resident  in  training  to  achieve  a  fundamental  understanding  of  the  structural  and  functional  anatomy  of  the  knee.  Thus,  the  initial  goal  of  this  chapter  is  to  review  the  complex  anatomic  relevant  components  of  the  knee.  After  establishing  this  anatomic  knowledge  base,  a  second  goal  of  this  chapter  is  to  provide  a  systematic  approach  for  interpretation  of  MRI  as  it  applies  to  the  clinical  presentation  of  internal  derangement  of  the  knee.  The  term  “Internal  Derangement”  is  used  to  cover  a  group  of  disorders  that  affect  the  normal  functioning  ligaments,  tendons,  or  cartilage  (including  the  meniscus)  of  the  knee  articulation.  From  a  technical  standpoint,  this  is  ideally  performed  with  a  high  field  strength  1.5  Tesla  or  3  T  MRI  scanner.  Three  conventional  MRI  planes  that  are  utilized  to  evaluate  the  knee  include  sagittal  (oblique),  coronal,  and  transaxial  planes.  While  a  detailed  explanation  of  MRI  protocols  and  MR  physics  is  beyond  the  scope  of  this  text,  fast  spin  echo  (FSE)  MRI  is  most  commonly  utilized  for  MRI  of  the  knee.  Specifically,  in  the  coronal  and  sagittal  planes,  T1,  T2,  and  intermediate-weighted  proton  density  FSE  sequences  are  often  utilized.  Fat  saturation  is  employed  on  some  of  the  fluid-weighted  sequences  to  better  detect  the  presence  of  edema  in  the  soft  tissues  or  bone  marrow.  A  spin  echo  or  gradient  echo  sequence  is  often  acquired  in  the  transaxial  plane.  MRI  of  the  knee  may  be  performed  without  contrast.  Alternatively,  utilization  of  gadolinium  contrast  agent  may  be  utilized  and  with  regard  to  internal  derangement;  this  is  particularly  useful  in  evaluating  the  postoperative  knee.  Administration  of  gadolinium  for  an  MR  arthrogram  may  be  employed.  This  may  be  performed  with  either  a  direct  or  indirect  technique.  With  the  direct  MR  arthrogram,  a  1:200  dilution  of  gadolinium  in  approximately  30  mL  of  sterile  saline  is  percutaneously  injected  into  the  knee  joint  using  a  22-gauge  needle.  The  indirect  MR  arthrogram  is  performed  after  an  intravenous  injection  of  gadolinium  contrast  followed  by  exercise  allowing  leakage  of  contrast  agent  from  the  synovium  into  the  joint  space  and  then  subsequent  MR  image  acquisition.1