Pediatric pelvis (AP view)

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The AP pelvis view is a routine view for pediatric patients to examine the hip joints, proximal femora, iliac crests and pelvic ring. The complications of pelvic pathology in pediatrics can significantly affect the child's future, highlighting the importance of proper patient positioning .

Indications

Aside from trauma and diagnosing suspected fracture and dislocation, the pediatric AP pelvis view is most commonly requested for diagnosis of developmental dysplasia of the hip (DDH) and slipped upper femoral epiphysis (SUFE). This view allows for pelvic radiograph lines (Shenton's line, Perkin's line and Hilgenreiner's line) to be drawn; demonstrating either normal or abnormal alignment of the pelvis.

Patient position

  • patient is supine with no rotation of the pelvis
  • ideally, patient legs are internally rotated
  • patient is placed on top of the detector

Technical factors

  • anteroposterior projection
  • centering point
  • collimation
    • laterally to the skin margins
    • superior to above the iliac crests
    • inferior to the proximal third of the femur
  • orientation
    • landscape
  • detector size
    • will vary depending on the patient's size
  • exposure
    • 63-70 kVp
    • 2-5 mAs
  • SID
    • 100 cm
  • grid
    • if patient thickness is above 10 cm, use of a grid is advisable

Image technical evaluation

  • criteria for pelvis remains the same as for adult pelvic radiographs
  • entirety of the bony pelvis is imaged from the iliac crests to the proximal third of the femur
  • no rotation
    • equal obturator foramen
    • equal concavity of the iliac wings

Practical points

Preparing the room beforehand (set up the detector, exposure and prepare lead gowns) is extremely beneficial for pelvis imaging as young children will often begin to cry the moment they are placed supine.

Ideally, if parental holding is required, the parent holds the child from the feet-end in order to be in the child's direct line of sight. This is to avoid the child rotating their pelvis to look at their parent;

  • this will require clear instructions for the parents to follow so that they do not allow rotation of the child's pelvis or motion artefact from kicking
  • if the parent is accompanying the child by holding them in position, whilst the parent puts on a lead gown, it is the radiographer's responsibility to ensure the baby does not roll off the x-ray table
  • if other methods can be used such as distraction techniques, or swaddling, this is ideal to avoid scattered radiation to parents and staff