title: MR imaging of avascular necrosis of the femoral head: value of small-field-of-view sagittal surface-coil images.
abstract: We compared coronal, large-field-of-view, body-coil MR images with sagittal, small-field-of-view, surface-coil images of 30 hips for their sensitivities in establishing the diagnosis of avascular necrosis; spatially localizing the avascular necrosis; and detecting joint-space narrowing, femoral head collapse, articular cartilage fracture, and joint fluid. We also compared the two separate plane/coil combinations for detection of the "double-line" sign (high signal inside a band of low signal, believed to be characteristic for avascular necrosis) and intertrochanteric conversion of hematopoietic marrow to fatty marrow. Coronal, large-field-of-view, body-coil images provided an adequate screening examination for the presence of avascular necrosis (sensitivity of 94%) and were preferred in all cases for mediolateral localization of focal abnormality. They were also better for assessing joint fluid and detecting fatty conversion of marrow. Sagittal, small-field-of-view, surface-coil images were preferred for anteroposterior localization in all cases and for superoinferior localization of focal abnormality in 15 of 18 cases. They detected additional cases of joint-space narrowing, articular cartilage fracture, and the double-line sign missed by coronal, body-coil images. Sagittal, small-field-of-view, surface-coil images are a valuable adjunct to MR evaluation of femoral avascular necrosis because they provide additional information that may be useful for planning surgical therapy.
authors.affiliation: Department of Radiology, University of Washington Hospital, Seattle 98195.
authors.forename: W P
authors.initials: WP
authors.lastname: Shuman
authors.forename: A A
authors.initials: AA
authors.lastname: Castagno
authors.forename: R L
authors.initials: RL
authors.lastname: Baron
authors.forename: M L
authors.initials: ML
authors.lastname: Richardson
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D005271:Femur Head Necrosis / Q000175:diagnosis*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000295:instrumentation / Q000379:methods; D008297:Male; D008875:Middle Aged