Detection of osseous change is limited in areas covered by prominent overlapping soft tissue or bowel gas [31]. If the osseous reaction involves cortical bone, then endosteal/periosteal callus may be visible with or without a fracture line through the cortex. If the trabecular bone is involved, then stress fractures are often more subtle, progressing from patchy areas of increased density into linear areas of sclerosis, oriented perpendicular to the trabeculae. US Area of Interest There is increasing evidence of the usefulness of ultrasound (US) in the early diagnosis of stress fractures of the extremities [44,45]. Although later US findings of stress fractures, including subcutaneous edema, periosteal thickening, cortical bone irregularity, local hyperemia [44-46], and periosteal callus are often nonspecific, these Stress (Fatigue-Insufficiency) Fracture findings provide useful information in the setting of suspected stress fracture. Because US cannot evaluate the subcortical bone, trabecular stress fractures may be missed. Variant 2: Adult. Suspect stress fracture, excluding vertebrae. Radiographs negative or indeterminate. Next imaging study. Area of Interest: pelvis, ankle, elbow, femur, foot, forearm, hand, hip, humerus, knee, leg tib/fib, ribs, sacrum, shoulder, or wrist. Bone Scan Whole Body with SPECT or SPECT/CT Area of Interest Bone scintigraphy shows stress fractures days to weeks earlier than radiographs in many instances and differentiates between osseous and soft tissue injury as well. Although bone scan was regarded as the reference standard examination for many years, MRI demonstrates stress abnormalities as early as bone scintigraphy and with as much sensitivity [25-28].
Stress Fatigue Insufficiency Fracture Including Sacrum Excluding Other Vertebrae PCAs. Detection of osseous change is limited in areas covered by prominent overlapping soft tissue or bowel gas [31]. If the osseous reaction involves cortical bone, then endosteal/periosteal callus may be visible with or without a fracture line through the cortex. If the trabecular bone is involved, then stress fractures are often more subtle, progressing from patchy areas of increased density into linear areas of sclerosis, oriented perpendicular to the trabeculae. US Area of Interest There is increasing evidence of the usefulness of ultrasound (US) in the early diagnosis of stress fractures of the extremities [44,45]. Although later US findings of stress fractures, including subcutaneous edema, periosteal thickening, cortical bone irregularity, local hyperemia [44-46], and periosteal callus are often nonspecific, these Stress (Fatigue-Insufficiency) Fracture findings provide useful information in the setting of suspected stress fracture. Because US cannot evaluate the subcortical bone, trabecular stress fractures may be missed. Variant 2: Adult. Suspect stress fracture, excluding vertebrae. Radiographs negative or indeterminate. Next imaging study. Area of Interest: pelvis, ankle, elbow, femur, foot, forearm, hand, hip, humerus, knee, leg tib/fib, ribs, sacrum, shoulder, or wrist. Bone Scan Whole Body with SPECT or SPECT/CT Area of Interest Bone scintigraphy shows stress fractures days to weeks earlier than radiographs in many instances and differentiates between osseous and soft tissue injury as well. Although bone scan was regarded as the reference standard examination for many years, MRI demonstrates stress abnormalities as early as bone scintigraphy and with as much sensitivity [25-28].