CT hip (protocol)

Last revised by Andrew Murphy on 23 Mar 2023

The CT hip protocol serves as an examination for the evaluation of the hip joint. It is often performed as a non-contrast study. However, it can be combined with a CT arthrogram for the evaluation of chondral and/or labral tears or a femoral neck version scan.

Note: This article aims to frame a general concept of a CT protocol for the assessment of the hip. Protocol specifics will vary depending on CT scanner type, specific hardware and software, radiologist and perhaps referrer preference, patient factors e.g. implants, specific indications.

A typical CT of the hip might look like as follows:

Typical indications include the following 1-6:

The main purpose of a dedicated hip CT is the depiction of the three-dimensional bony morphology of the femoral head-neck area and the acetabulum. This is especially useful for preoperative planning or the assessment of the postoperative hip and includes a depiction of the following 1-6:

A CT arthrogram of the hip can be done for the assessment of the articular cartilage and the detection of labral tears if MRI is contraindicated 4.

  • patient position
    • supine position
  • tube voltage
    • ≤120 kVp
  • tube current
    • as suggested by the automated current adjustment mode
  • scout
    • iliac crest to the proximal half of the femur
  • scan extent
    • might vary depending on the indication e.g. preoperative planning or implants
    • should include the anterior inferior iliac spine and 3-5 cm below the lesser trochanter
  • scan direction
    • craniocaudal
  • scan geometry
    • field of view (FOV): 120-250 mm (should be adjusted to increase in-plane resolution)
    • slice thickness: ≤1.25 mm, interval: ≤0.625 mm
    • reconstruction algorithm: bone, soft tissue
  • multiplanar reconstructions
    • axial images: strictly axial to the body axis
    • coronal images: strictly coronal to the body axis
    • sagittal images: strictly sagittal to the body axis
    • axial oblique: parallel to the femoral neck axis
    • slice thickness: ≤2 mm, overlap 50%
    • additional coronal and sagittal centered on the femoral stem might be obtained
  • mindful patient positioning with slight internal rotation of the lower limb prior to scanning might reduce reconstructions
  • the extent of the examination should be tailored to the specific indication or clinical question
  • reconstructions should be centered on the hip in question but should also include a wide field of view to depict acetabular and captured pelvic morphology 6
  • imaging of implants 6
  • 3D reconstruction techniques might be beneficial in the setting of preoperative planning and/or visualization of fractures

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