Prenatal MRI findings of fetuses with congenital high airway obstruction sequence.
OBJECTIVE
To define the MRI findings of congenital high airway obstruction sequence (CHAOS) in a series of fetuses.


METHODS
Prenatal fetal MR images were reviewed in seven fetuses with CHAOS at 21 to 27 weeks of gestation. The MRI findings were reviewed. The MRI parameters evaluated included the appearance of the lungs and diaphragm, presence or absence of hydrops, amount of amniotic fluid, airway appearance, predicted level of airway obstruction, and any additional findings or suspected genetic syndromes.


RESULTS
All the fetuses viewed (7 of 7) demonstrated the following MRI findings: dilated airway below the level of obstruction, increased lung signal, markedly increased lung volumes with flattened or inverted hemidiaphragms, massive ascites, centrally positioned and compressed heart, as well as placentomegaly. Other frequent findings were anasarca (6 of 7) and polyhydramnios (3 of 7). MRI identified the level of obstruction as laryngeal in five cases and tracheal in two cases. In four of the patients, surgery or autopsy confirmed the MRI predicted level of obstruction. Associated abnormalities were found in 4 of 7 (genetic syndromes in 2). Postnatal radiography (n = 3) showed markedly hyperinflated lungs with inverted or flattened hemidiaphragms, strandy perihilar opacities, pneumothoraces and tracheotomy. Two fetuses were terminated and one fetus demised in utero. Four fetuses were delivered via ex utero intrapartum treatment procedure.


CONCLUSIONS
MRI shows a consistent pattern of abnormalities in fetuses with CHAOS, accurately identifies the level of airway obstruction, and helps differentiate from other lung abnormalities such as bilateral congenital pulmonary airway malformation by demonstrating an abnormally dilated airway distal to the obstruction.
Guimaraes
Carolina V A
CV
Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229-3039, USA. carolina.guimaraes@cchmc.org
Linam
Leann E
LE
Kline-Fath
Beth M
BM
Donnelly
Lane F
LF
Calvo-Garcia
Maria A
MA
Rubio
Eva I
EI
Livingston
Jeffrey C
JC
Hopkin
Robert J
RJ
Peach
Elizabeth
E
Lim
Foong-Yen
FY
Crombleholme
Timothy M
TM
D000015:Abnormalities, Multiple; D000402:Airway Obstruction / Q000151:congenital / Q000473:pathology*; D001201:Ascites / Q000473:pathology; D003964:Diaphragm / Q000002:abnormalities; D005260:Female; D005315:Fetal Diseases / Q000473:pathology*; D006801:Humans; D008168:Lung / Q000473:pathology; D008279:Magnetic Resonance Imaging; D010922:Placenta Diseases / Q000473:pathology; D011247:Pregnancy; D011296:Prenatal Diagnosis; D012189:Retrospective Studies