Answer for BIR CoW 01 Feb 2026
Insufficiency fracture
Findings
T1/ T2 hypointense fracture line noted in the medial malleolus with adjoining bone marrow edema. No obvious fracture in visualised CT images of ankle joint.
Discussion
An insufficiency fracture occurs when normal stress is applied to weak bone, often due to osteoporosis, osteomalacia, or other metabolic bone diseases, typically in elderly patients. • CT, insufficiency fractures may show linear or band-like areas of sclerosis, cortical disruption, or subtle fracture lines, often without obvious displacement. • MRI, they appear as low signal intensity lines on T1-weighted images with surrounding bone marrow edema (high signal on T2/STIR); edema is usually more diffuse, reflecting the weakened bone. Differential diagnosis: In contrast, a stress (fatigue) fracture occurs when abnormal repetitive stress is applied to normal bone, usually in young athletes or military recruits. • CT, stress fractures may appear as thin fracture lines or periosteal reaction, sometimes with cortical thickening, • MRI, they typically show focal bone marrow edema on T2/STIR surrounding a linear low signal fracture line on T1, often with more localized edema compared to insufficiency fractures.
Findings
T1/ T2 hypointense fracture line noted in the medial malleolus with adjoining bone marrow edema. No obvious fracture in visualised CT images of ankle joint.
Discussion
An insufficiency fracture occurs when normal stress is applied to weak bone, often due to osteoporosis, osteomalacia, or other metabolic bone diseases, typically in elderly patients. • CT, insufficiency fractures may show linear or band-like areas of sclerosis, cortical disruption, or subtle fracture lines, often without obvious displacement. • MRI, they appear as low signal intensity lines on T1-weighted images with surrounding bone marrow edema (high signal on T2/STIR); edema is usually more diffuse, reflecting the weakened bone. Differential diagnosis: In contrast, a stress (fatigue) fracture occurs when abnormal repetitive stress is applied to normal bone, usually in young athletes or military recruits. • CT, stress fractures may appear as thin fracture lines or periosteal reaction, sometimes with cortical thickening, • MRI, they typically show focal bone marrow edema on T2/STIR surrounding a linear low signal fracture line on T1, often with more localized edema compared to insufficiency fractures.
Note:
We do not discourage differential diagnosis. But all the differentials must satisfy the findings noted in the case.
If you feel you have answered rightly but cannot find your name in the above list, please call 09551942599.
Did you Know?
The order in which the names appear in this winner's list is based on the time of submission. The first person to send the correct answer gets his/her name on top of the list!
We do not discourage differential diagnosis. But all the differentials must satisfy the findings noted in the case.
If you feel you have answered rightly but cannot find your name in the above list, please call 09551942599.
Did you Know?
The order in which the names appear in this winner's list is based on the time of submission. The first person to send the correct answer gets his/her name on top of the list!