NucMed Boards Prep
IMAGE INTERPRETATION · BONE IMAGING

Cellulitis vs Osteomyelitis on Three-Phase Bone Scan

Three-phase bone scan showing increased flow/blood pool in soft tissues with normal delayed bone uptake — pattern of cellulitis
Three-phase bone scan showing increased flow/blood pool in soft tissues with normal delayed bone uptake — pattern of cellulitis

Provided clinical image

Question

A three-phase bone scan is performed in a diabetic patient with a red, swollen foot. The scan shows increased uptake in the FLOW and BLOOD POOL phases over the dorsal foot soft tissues, but the DELAYED phase shows normal bone uptake without focal abnormality. This pattern is most consistent with:

  1. AOsteomyelitis of the metatarsals
  2. BStress fracture of the fifth metatarsal
  3. CCRPS (Complex Regional Pain Syndrome)
  4. DCellulitis without underlying osteomyelitis
Show the answer and explanation

D. Cellulitis without underlying osteomyelitis

Cellulitis causes increased vascular activity (increased flow and blood pool phases) due to soft-tissue hyperemia, but WITHOUT increased delayed bone uptake, since the infection has not yet invaded bone. In contrast, OSTEOMYELITIS shows increased uptake in ALL THREE phases — flow, blood pool, AND delayed (bone) — because the infection directly involves the cortex and medullary bone. This distinction on three-phase bone scan is clinically critical in the diabetic foot, where distinguishing cellulitis from osteomyelitis guides antibiotic selection and surgical planning.

More bone imaging images

Normal whole-body Tc-99m MDP bone scan — anterior and posterior projectionsNormal Physiologic Uptake on a Bone Scan Tc-99m MDP bone scan showing uptake in the tibial regionShin Splints on Bone Scan: Medial Tibial Stress Syndrome Tc-99m MDP bone scan — femoral head and neck regionAvascular Necrosis of the Femoral Head on Bone Scan Three-phase bone scintigraphy — serial imagesFlare Phenomenon on Bone Scan After Chemotherapy Whole-body Tc-99m MDP bone scan in a patient with prostate cancerBone Scan for Staging High-Risk Prostate Cancer Bone scan showing focal intense uptake with deformity in the femurFibrous Dysplasia on Bone Scan (Shepherd’s Crook)
← Photopenic Bone Lesions: Multiple MyelomaNormal Physiologic Uptake on a Bone Scan →

All 130 nuclear medicine images by category →

Practise image interpretation in the app

All 130 images as an interactive quiz, alongside 500 NMTCB and ARRT(N) questions with worked explanations, case studies and timed mock exams. 25 questions are free, no card and no account.

Start free — no card

Download on the App StoreGet it on Google Play