Diagnostic Approach for Persistent Foot Pain

Clinical Decision Algorithm Based on Pain Location

The American College of Radiology recommends MRI foot without IV contrast or ultrasound as appropriate next steps for patients with plantar heel pain and clinical concern for plantar fasciitis or plantar fascia tear 1, 2, 3
Ultrasound demonstrates 80% sensitivity and 88% specificity for plantar fascia pathology, allowing dynamic examination 4
For midfoot pain with suspected osseous origin, MRI foot without IV contrast or CT foot without IV contrast are equally appropriate, as standard radiographs detect only 12-56% of stress fractures initially 1, 2, 3, 5, 6
Stress fractures occur most frequently in the calcaneus and metatarsals, less commonly in the navicular, cuboid, and cuneiform bones 1, 2, 3
For dorsal foot pain, MRI without contrast or CT without contrast are equivalent alternatives for detecting stress fractures of the metatarsals, navicular, cuboid, or cuneiform bones 5
Three-phase bone scan has 100% sensitivity and negative predictive value for ruling out stress fractures when radiographs are negative 5
Consider extensor tendonitis if pain worsens with active toe extension or resisted dorsiflexion, with point tenderness along the extensor tendons 5

MRI detects bone and joint abnormalities, signs of inflammation, and soft tissue pathology with good to excellent sensitivity and specificity across various disease states 7
MRI identifies occult fractures, bone marrow edema, stress reactions, tendon pathology, ligament injuries, and nerve compression syndromes that are invisible on radiographs 1, 2, 3, 4
Patients with clinically suspected pathology can exhibit normal radiographs but show clear abnormalities on MRI confirming bone/joint involvement 7

Never rely solely on initial radiographs to exclude stress fractures, given the 12-56% sensitivity 5, 6
Avoid corticosteroid injections near extensor tendons due to risk of tendon rupture 5
Do not order ankle radiographs when evaluating tarso-navicular pain, as this joint will not be properly visualized; foot radiographs are required 6
Weight-bearing radiographs are essential when feasible, as non-weight-bearing films may underestimate joint instability and malalignment 7, 4

Three-phase bone scan is appropriate for persistent post-traumatic foot pain when clinical concern includes Complex Regional Pain Syndrome (CRPS) Type I 1, 2, 3
CT without IV contrast is particularly useful for evaluating tarsal coalitions and for surgical planning of joint pathology 5, 6
SPECT-CT or nuclear imaging may support diagnosis of active Charcot neuro-osteoarthropathy in diabetic patients with suspected disease 7

Ultrasound offers specific advantages in certain clinical scenarios, including dynamic exploration of the foot and assessment of synchondrosis stability and tendon tears 1, 2, 3
Power Doppler identifies increased blood supply in sesamoiditis, Morton's neuroma, intermetatarsal bursitis, chronic plantar plate injury, or Freiberg's infraction 1, 2, 3

The American College of Radiology suggests that sesamoiditis manifests as plantar great toe pain with increased blood supply detectable on Power Doppler ultrasound, and intermetatarsal bursitis presents similarly to Morton's neuroma with forefoot pain between metatarsal heads 8, 9
The American College of Radiology recommends considering Freiberg's infraction, which causes localized dorsal forefoot pain and is detectable on Power Doppler ultrasound showing increased blood supply 8, 9

The American College of Radiology advises that MRI foot without IV contrast or ultrasound are the appropriate next imaging studies for persistent metatarsalgia after negative radiographs, with Power Doppler ultrasound specifically identifying increased blood supply in sesamoiditis, Morton's neuroma, intermetatarsal bursitis, chronic plantar plate injury, or Freiberg's infraction 8, 9

The American College of Radiology notes that dynamic exploration with ultrasound allows assessment of synchondrosis stability and tendon tears with direct clinical correlation, and comparative evaluation with the asymptomatic foot provides additional diagnostic information 8, 9
The American College of Radiology suggests that Power Doppler ultrasound specifically identifies the increased vascularity pattern distinguishing between the various causes of metatarsalgia 8, 9