Imaging Tumours

Principles

  • Imaging used for four aspects
    • Make the diagnosis
    • Stage the lesion
    • Plan the treatment
      • Staging
      • Biopsy
    • Assess the response

Enneking’s Questions

  • What is the location of lesion?
  • What is the lesion doing to the bone?
  • What is the bone’s reaction to the lesion?
  • What is the tumour matrix?

Imaging Modalities

Imaging Tumours, radiograph of a lytic tumour of the proximal femur
Radiograph of a lytic tumour of the proximal femur. Image by Hellerhoff, Wikimedia Commons, CC BY-SA 3.0.

X-ray

  • Initial examination
  • Main-stay
    • Evaluation of
      • Location
      • Margin
      • Periosteal Reaction
      • Matrix

Bone Scan

  • Most lesions have ↑ uptake
  • Screening tool
  • Non-anatomical
  • False negative with
  • Crude indicator of extent of lesion & response to treatment
  • Main role is demonstration of multiple lesions

CT Scan

  • Best for assessing mineralisation & bony details
  • Benign bone tumours
    • Violation of cortex
    • Matrix mineralisation
  • Shows local extent of tumour
    • Intraosseous
    • Extension into soft tissue
  • Shows areas that plain XR visualise poorly
    • Spine
    • Pelvis

MRI

  • Best for assessing soft tissue
  • Very sensitive for
  • Shows relationship to neurovascular bundle well
  • May be oversensitive
    • Oedema (reactive zone) vs Tumour

Diagnosis

  • Mainstay is plain film
  • Other modalities contribute
    • CT Scan
      • Defines architecture of lesion
    • MRI Scan
      • Determines extent of disease (can be over-sensitive)
    • Bone Scan
      • Locates other lesions

Spread

  • MRI is best
    • Intramedullary spread
      • T1 sequence
        • T1 with Fat Suppression/ Inversion Recovery
    • Cortical breakthrough
      • T2 sequence
    • Soft tissue spread
      • T2 sequence
    • Relationship to vessels
      • T2 sequence

Metastases

  • Lungs
    • CXR – see mets >/= 1cm
    • CT Scan – see mets >/= 2mm
  • Bone
    • Bone scan

Radiological Diagnosis of Bone Tumours

Watt Criteria (1985)

QuestionInterpretation
1. Solitary or multiple?Multiple lesions more likely to represent metastatic lesions or systemic disorder. Solitary more often primary tumour
2. What type of bone involved?Metastatic disease presents most in axial skeleton. Osteoid osteoma rarely in intramembranous bones
3. Where is lesion in bone?Fibrous cortical defect is cortical in location. Chondroblastoma epiphyseal. GCT is subarticular in mature skeleton
4. Are margins well or ill defined?Slow growing tumour has short zone of transition with normal bone. Aggressive tumours more permeative
5. Is there a bony reaction?More indolent the greater the sclerosis
6. Does lesion contain calcification?Useful signs of cartilage tumour

Reviewed by Professor Phong Tran, Head of Orthopaedic Surgery, Western Health. Last updated 10 October 2026.