Emphysematous Osteomyelitis: Novel Use of PET-MRI and a Review of Characteristic Imaging Findings.

INTRODUCTION: Emphysematous Osteomyelitis (EO) is an extremely rare bone infection caused by gas-forming bacteria with few documented cases in the literature. Our study aims to highlight characteristic imaging features, including the novel use of positron emission tomographymagnetic resonance imaging (PET-MRI) in diagnosing this potentially fatal entity. CASE: Radiography and computed tomography (CT) of the pelvis were performed due to complaints of persistent back pain in a 36-year-old male with a history of recent abdominal aorta surgery. Sacroiliac joint aspiration was performed, and a follow-up PET-MRI was subsequently performed. RESULTS: Radiography and CT demonstrated bilateral sacroiliitis, osteonecrosis and EO in the bony pelvis. Left sacroiliac joint aspiration identified Staphylococcus aureus as the causative organism. PET-MRI revealed EO with left iliopsoas abscess and abdominal aortic graft infection. The patient's symptoms resolved following antibiotic therapy and image-guided abscess drainage. CONCLUSION: EO is a lethal variant of osteomyelitis with a dearth of published cases. Pertinent imaging characteristics of EO on radiography, CT and PET-MRI are discussed here, along with a review of the literature surrounding this rare condition.

Radiologic Features with Pathologic Correlation of an Unusual Large Intraosseous Skull Cavernous Hemangioma.

BACKGROUND Intraosseous cavernous skull hemangiomas are rare benign vascular tumors that are usually found incidentally on imaging, with an asymptomatic and slow-growing course. We present a case in which the patient had a mass on her forehead for many years, which began to grow rapidly after head trauma. Imaging characteristics play a crucial role in the diagnosis and description of this disease, and in differentiating it from other more common calvarial lesions that may present with a similar clinical picture. Here, we report an unusual presentation of a large skull hemangioma and discuss the different radiologic imaging findings and pathologic correlations. CASE REPORT A 58-year-old female with history of a lump on her forehead since childhood, which began to grow rapidly after experiencing a closed-head injury. Due to its large size, she went on to seek further management. Radiologic images revealed a frontal skull lesion suggestive of an intraosseous hemangioma. She underwent embolization of the tumor, and 2 days later underwent bilateral frontal craniectomy and cranioplasty. Histopathologic findings confirmed this diagnosis. CONCLUSIONS Intraosseous skull hemangioma may be confidently diagnosed and differentiated from other skull lesions by its imaging characteristics. An accurate diagnosis is essential to selecting correct management and avoiding complications.