title: Normal placenta: gadolinium-enhanced dynamic MR imaging.
abstract: OBJECTIVE
  To establish the appearance of the normal placenta on dynamic, gadolinium-enhanced magnetic resonance (MR) images.
  
  
  METHODS
  Eleven patients underwent MR imaging for suspected uterine (four patients) or placental (seven patients) abnormalities (but not placental insufficiency or intrauterine growth retardation). Unenhanced or gadolinium-enhanced, T1-weighted, fat suppressed, spoiled gradient-recalled-echo MR images and T2-weighted, half-Fourier, single-shot, spin-echo-train MR images were obtained. Two investigators retrospectively evaluated the images to determine the rate, pattern, and degree of placental contrast material enhancement with myometrial enhancement as a reference.
  
  
  RESULTS
  The diagnoses were normal placenta (six patients), abnormal placental position (four patients), and subchorionic hematoma (one patient). The placenta rapidly and intensely enhanced on images acquired immediately after contrast material administration and preceded substantial enhancement of the myometrium. Immediately postcontrast images showed closely packed 2-3-cm lobules of placental enhancement in third-trimester pregnancies and heterogeneous placental enhancement in second-trimester pregnancies. In all cases, placental enhancement became more homogeneous over time. The placenta could be readily distinguished from the myometrium. All neonates were healthy with no evidence of intrauterine growth retardation.
  
  
  CONCLUSIONS
  Normal placental enhancement is intense on immediately postcontrast images and precedes substantial myometrial enhancement. Third-trimester placentas exhibit a lobular pattern of enhancement, while second-trimester placentas exhibit heterogeneous enhancement.
authors.affiliation: Department of Radiology, University of North Carolina, Chapel Hill 27599-7510, USA.
authors.forename: H B
authors.initials: HB
authors.lastname: Marcos
authors.forename: R C
authors.initials: RC
authors.lastname: Semelka
authors.forename: S
authors.initials: S
authors.lastname: Worawattanakul
mesh_terms: D000328:Adult; D003287:Contrast Media; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D007231:Infant, Newborn; D008279:Magnetic Resonance Imaging; D010920:Placenta / Q000033:anatomy & histology* / Q000473:pathology; D010922:Placenta Diseases / Q000175:diagnosis; D011247:Pregnancy; D011264:Pregnancy Trimesters; D012016:Reference Values
chemical_list: D003287:Contrast Media; D019786:Gadolinium DTPA