Breast MRI interventions

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  • Remember! 10% of enhancing lesions disappear on day of biopsy; get f/u MRI in 6 months

Contents

[edit] MRI Vacuum Assisted Biopsy

  • Stylet, introducer with black washer, oburator, 9G biopsy needle, needle guide.
  • Don’t need to add any distance to depth b/c needle and cm markings take that into consideration.
  • The obturator is in when do images and the tip of it lines up with the center of the collecting chamber of the needle; be within 2 mm of the lesion b/c collecting chamber is large and with suction will get it.
  • POST BIOPSY/CLIP MAMMOGRAM IS ESSENTIAL!

[edit] MRI Needle Localization

  • Don’t overshoot b/c of the accordion effect when taken out of compression like in stereo where wire or clip will be in a different location from the biopsy site in the Z direction, usually more deep (medial if using a lateral approach & vice-versa) so with NL go only 5 mm beyond lesion; don’t need needle guide (2 cm) for NL so only need to add 5 mm to depth

[edit] Thin Breasts

  • Use least amount of compression necessary
  • Roll the breast
  • Generous skin wheal of anesthetic
  • Smaller probe (petite instead of the grande) has a rounded rather than a sharp tip
  • Stereo “reverse compression paddle” technique equivalent: 8 channel with grid on both sides.

[edit] Implants

  • Same as above
  • Go posterior to lesion and suction anteriorly only

[edit] Superficial Lesions

  • Same as above
  • Don’t use needle guide b/c want to make sure that the collecting chamber is completely within breast otherwise won’t get suction
  • Put needle guide one box below in grid so that you know how far to go in with the black washer

[edit] Medial Lesions

  • Oblique positioning with breast in C/L breast opening but only if pt is agile and not large OR 8 channel coil but limited access to posterior tissues b/c of C/L breast and pad so better for anteromedial tissues otherwise go from lateral.

[edit] Posterior Lesions

  • Put needle as posterior as possible and suction posteriorly
  • Can go behind grid

[edit] Underestimation with 9G MRVAB: same as with stereo literature even though bigger needle

  • ADH : DCIS 40% (Stereo 14 G: ADH DCIS/CA 40-50%)
  • DCISCA 20%
  • DCIS  Inv. CA 17%
  • Stereo 11 G: ADH DCIS/CA 20%
  • Stereo 11 G: DCISCA 10%

[edit] Discordance

  • ~3% MSKCC and cancer in 25% of the discordant lesions
  • Important when evaluating dis or concordance to review bx images and
  • Post bx mammo images and correlate with prebx MR images- did you get it?
  • Get post bx MRI in 1 month if not sure-have a low threshold

[edit] References

  • MSKCC Breast Cancer Conference 2006