CT Hip / Bony Pelvis

Indications

• Acetabular and proximal femoral fracture characterization and surgical planning
• Occult hip fracture when MRI is unavailable or contraindicated
• Prosthesis assessment: periprosthetic fracture, loosening, component position
• Femoroacetabular impingement / femoral version measurement
• Pelvic ring fracture (bony pelvis coverage)

Patient prep

• Remove metal from pockets/clothing over the pelvis
• Supine, feet first, legs extended
• No contrast for routine osseous indications

Contrast

Technique

• Internally rotate the feet (toes pointing toward each other, secured) — standardizes femoral version and profiles the femoral necks
• Coverage: hip — above the iliac crest through the proximal femur, including the ENTIRE fracture or prosthesis; bony pelvis — iliac crest through the ischial tuberosities
• Thin 0.5-1 mm isotropic recon, bone and soft-tissue algorithms; coronal/sagittal reformats aligned to the pelvis
• Prosthesis present: use metal artifact reduction (MAR) recon or raise kVp ~15%, and add bilateral-hip axial/coronal recons for side-to-side comparison
• Femoral version question: add a short axial block through the femoral condyles as the rotational reference
• 3D VR for acetabular/pelvic ring fracture surgical planning

Series / Sequences

Key points

• Internal rotation of the feet is a small step that standardizes every version/neck measurement — make it routine
• Always include the entire prosthesis or fracture; stopping mid-hardware is the most common coverage error
• Judet-view equivalent oblique reformats classify acetabular fractures (anterior/posterior column and wall)
• MRI remains most sensitive for truly occult femoral neck fracture; CT is the fast alternative when MRI can't happen

References