scan protocol

role of ultrasound

  • location – label surrounding anatomy, use a body marker on the film.
  • compare to the other side
  • measure in 3 planes:
      1. ap
      2. long
      3. trans
  • volume if fluid
  • echogenicity – hypo,hyper,isoechoic,anechoic, calcified compared to the surrounding tissue
  • texture: homo.heterogeneous, simple or complex
  • surrounding tissue : check the lump for spread into the muscle has it broken the fascia,the skin or invasion anywhere else
  • mass effect: is it compressing any vessels or ducts
  • posterior: shadowing ,enhancement or no change
  • vascularity: non-detected, present – increased or decreased.

limitations

if there has been any intervention, sutures or gas in the overlying tissue will obscure detail. 

if the patient is obese it will limit visibility.

if the patient is unable to show the sonographer the correct  region of interest.

if the patient is disabled and cannot move into a position that gives easy access to the area.

patient preparation

depending on the position of the lump on the patient, make sure the patient and the sonographer are comfortable. usually if the patient is  lying down the patient will stay still.

equipment setup

  • use of a high resolution probe (7-15mhz) is essential when assessing superficial structures.
  • careful scanning technique to avoid anisotropy (and possible misdiagnosis).
  • use panoramic to get both edges in the same image
  • look with and without harmonics and compound imaging
  • may need to use a curved linear array robe if it travels deep or it is a high attenuating lesion with calcification etc
  • beam steering or compounding can help to overcome anisotropy in linear structures such as tendons.
  • good colour / power / doppler capabilities when assessing vessels or vascularity of a structure.
  • be prepared to change frequency output of probe (or probes) to adequately assess both superficial and deeper structures.

common pathology

normal anatomy and assymetry may be misintepretedas a lump/swelling.
  1. lipoma
  2. sebaceous cyst
  3. haematoma
  4. granuloma
  5. neuroma
  6. lymph node
  7. branchial cleft cyst
  8. mandibular abscess
  9. muscle herniation
  10. abdominal wall fibromatosis
  11. cyst
  12. cellulitis
  13. foreign body
  14. fat necrosis
  15. sarcoma
  16. hernia
  17. superficial thrombophlebitis

scanning technique

  • this will vary depending on the position of the lump.
  • the main thing is to have plenty of gel !!
  • try to get the patient to sit or stand in a position that it can be easily felt.
  • make sure the patient and the sonographer are comfortable.

usually the patient knows where the lump is and can tell the sonographer how it is best felt. if the patient does not know where the lump is because they did not feel it only their doctor did, then a phone call to the practitioner may need to be made if no lump can be located.

basic hardcopy imaging

  • the lump must be shown in 2 planes at 90 degrees to each other.
  • it must have a colour doppler box put over the entire region to assess for flow. also a spectral waveform is helpful to check for arterial or venous flow.
  • an image close to an known organ or tissue plane, labelled with a body marker. sometimes a measurement from a landmark is useful. eg from the umbilicus or sternal notch etc is helpful .