title: Osteoid osteoma and osteoblastoma: MRI appearances and the significance of ring enhancement.
abstract: We assessed the value of contrast-enhanced fat-suppressed MRI on nine patients with osteoid osteomas and osteoblastomas. The results were compared with plain films, bone scintigraphy, computed tomography (CT) and pathological specimens. On contrast-enhanced fat-suppressed T1-weighted images the non-calcified nidi showed homogeneous enhancement, whereas the calcified lesions showed a ring enhancement sign that was proportional in intensity to the extent of the remaining part of the vascularized nidus. The degree of bone marrow and soft tissue enhancement was relative to the size and reactive inflammatory changes of the lesions. Although CT was diagnostic in most of the cases and more specific to show the calcified lesions, MRI was confirmatory in one case. We concluded that, although CT is the primary diagnostic investigation in osteoid osteomas, MRI can be reserved for equivocal cases.
authors.affiliation: Department of Radiology and Imaging, Riyadh Armed Forces Hospital, Saudi Arabia.
authors.forename: B A
authors.initials: BA
authors.lastname: Youssef
authors.forename: M C
authors.initials: MC
authors.lastname: Haddad
authors.forename: A
authors.initials: A
authors.lastname: Zahrani
authors.forename: H S
authors.initials: HS
authors.lastname: Sharif
authors.forename: J L
authors.initials: JL
authors.lastname: Morgan
authors.forename: M
authors.initials: M
authors.lastname: al-Shahed
authors.forename: A
authors.initials: A
authors.lastname: al-Sabty
authors.forename: R
authors.initials: R
authors.lastname: Choudary
mesh_terms: D000293:Adolescent; D000328:Adult; D001859:Bone Neoplasms / Q000175:diagnosis*; D002648:Child; D002675:Child, Preschool; D005266:Femoral Neoplasms / Q000175:diagnosis; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D018215:Osteoblastoma / Q000175:diagnosis*; D010017:Osteoma, Osteoid / Q000175:diagnosis*; D013125:Spinal Neoplasms / Q000175:diagnosis; D013628:Talus; D013977:Tibia; D014057:Tomography, X-Ray Computed