Fetal sheep development on ultrasound and magnetic resonance imaging: a standard for the in utero assessment of models of congenital abnormalities.
OBJECTIVE
To establish normative data for the size, conspicuity, and imaging characteristics of normal developing fetal sheep organs on ultrasound (US) and magnetic resonance (MR) imaging.


METHODS
US and MR images of ten normal pregnant sheep, at 40, 65, 90, 115, and 140 gestational days (term = 145 days), were scored for organ conspicuity and imaging characteristics. Imaging biometry was correlated with specimens. Gestational age-based growth parameters were modeled using regression.


RESULTS
Imaging biometry showed excellent correlation with specimens. Kidney, bladder, stomach, lung, liver, and spine were seen well from 65 days to term by US. More organs were consistently visible from 90 days to term by MR than by US. Most organ imaging characteristics tended not to change throughout gestation.


CONCLUSIONS
Normal fetal sheep biometry, organ conspicuity, and imaging characteristics are established for US and MR and have potential use for the in utero assessment of sheep models of congenital abnormalities.
Ward
Valerie L
VL
Department of Radiology, Children's Hospital, Harvard Medical School, Boston, Mass. 02115, USA. valerie.ward@childrens.harvard.edu
Estroff
Judy A
JA
Nguyen
Hiep T
HT
Lakshmanan
Yegappan
Y
Hayward
Alison
A
Jaramillo
Diego
D
Zurakowski
David
D
Dunning
Patricia S
PS
Peters
Craig A
CA
Barnewolt
Carol E
CE
D000818:Animals; D001699:Biometry; D000013:Congenital Abnormalities / Q000175:diagnosis* / Q000000981:diagnostic imaging; D005260:Female; D047109:Fetal Development; D005325:Fetal Organ Maturity; D005865:Gestational Age; D008279:Magnetic Resonance Imaging; D023421:Models, Animal; D015233:Models, Statistical; D011247:Pregnancy; D011296:Prenatal Diagnosis / Q000592:standards*; D012756:Sheep / Q000196:embryology*; D016216:Ultrasonography, Prenatal