Diagnostic Criteria and Methods for Plantar Fasciitis

Imaging Methods

The American College of Radiology recommends MRI as the most sensitive imaging study for diagnosing plantar fasciitis, allowing accurate characterization of the plantar fascia and adjacent soft tissues/bones 1, 2
Weightbearing radiographs should be the initial imaging study for painful heel, with 85% sensitivity and 95% specificity for plantar fasciitis 3
Ultrasound has good sensitivity (80%) and specificity (88%) compared to MRI, with diagnostic accuracy findings including 69% for abnormal focal echogenicity within plantar fascia, 60% for edema around plantar fascia, 78% for perifascial edema, 69% for rupture of plantar fascia, and 56% for associated calcaneal spur 1, 2
US elastography shows higher sensitivity (95%) and specificity (100%) than conventional US (66% and 75%) 2, 4
Bone Scan with SPECT or SPECT/CT can be useful with increased specificity compared to bone scintigraphy alone, and a characteristic pattern on 3-phase bone scintigraphy helps differentiate plantar fasciitis from calcaneal stress/avulsion fractures 1, 4

If diagnosis is unclear or symptoms persist beyond 3 months, obtain weightbearing radiographs to exclude other pathologies, and consider MRI for definitive evaluation when diagnosis remains uncertain 1, 2, 3

MRI findings should always be correlated with clinical symptoms to avoid overcalling plantar fasciitis, as some findings can be seen in asymptomatic patients 1, 2