Diagnostic Imaging for Stress Fractures

Initial Evaluation

The American College of Radiology recommends plain radiographs as the first imaging study for all patients with suspected stress fractures, due to their high specificity, although they have low sensitivity (15-35%) 3, 1
If radiographic findings are conclusive for stress fracture, no further imaging is necessary, as initial radiographs can confirm the diagnosis with high specificity 3

The American College of Radiology suggests MRI without contrast as the preferred second-line imaging modality for diagnosing stress fractures after initial negative radiographs, due to its superior sensitivity and specificity compared to other modalities 1, 2
MRI without contrast demonstrates stress abnormalities as early as bone scintigraphy with equivalent sensitivity and superior specificity, and can identify associated soft tissue injuries or alternative diagnoses 4, 2
MRI provides both diagnostic and prognostic information, does not use ionizing radiation, and is particularly valuable for evaluating stress fractures in high-risk locations such as the femoral neck and head 5, 2

The American College of Radiology recommends immediate MRI for suspected stress fractures in high-risk locations, including the anterior tibial diaphysis, lateral femoral neck, femoral head, patella, medial malleolus, navicular, fifth metatarsal base, proximal second metatarsal, tibial hallux sesamoid, and talus, as delayed diagnosis can lead to displacement, nonunion, avascular necrosis, or need for surgical intervention 3, 5, 2
Detection of osseous changes is more limited in areas covered by prominent overlapping soft tissue, making MRI particularly useful in these cases 5, 6

The American College of Radiology advises against relying solely on negative initial radiographs when clinical suspicion is high, as this can lead to delayed diagnosis and fracture progression 2
The American College of Radiology also recommends against using CT with IV contrast or MRI with contrast for stress fracture evaluation, as they provide no additional benefit over non-contrast CT or MRI 1, 6