Presentation
Right sided chronic pain and tenderness around the inferior pubic ramus.
Patient Data
Plain radiograph shows an elongated, dense sclerotic bone lesion in the right femoral neck, otherwise unremarkable.
Ultrasound of the painful region also did not reveal any abnormality.
Narrowed ischiofemoral space on the right. Contrast was given due to tumor rule out being mentioned on the request form. On the postcontrast sequences marked, diffuse enhancement can be observed in bilateral quadratus muscles in the ischiofemoral space. A subtle corresponding high signal can be observed on the STIR sequence, but its coronal plane makes the changes difficult to appreciate.
The ovoid dense sclerotic bone lesion along the anterior cortex of the right femoral neck shows no malignant features, and - since its long axis is oriented along the trajectory of the trabecular meshwork - likely represents an unusually large enostosis.
Incidental right ovarian cyst.
Representative axial T1 FS postcontrast image showing the marked narrowing of the ischiofemoral space on the right (15 vs. 22 mm), with corresponding enhancement in the quadratus muscle, the latter present bilaterally.
Case Discussion
The diagnosis of ischiofemoral impingement can be elusive if the clinical picture is unclear, and the imaging requests are thus ambiguous. Now if you take a second look at the radiograph the narrowing of the right ischiofemoral space seems to be apparent, which is in no small part the benefit of hindsight (bias). MRI is currently the mainstay of the diagnosis of ischiofemoral impingement, and the narrowing of the ischiofemoral space should be interpreted together with ancillary features such as localized edema/enhancement.
Also contributed by Dr. Omar Giyab