MRI and DWI: feasibility of DWI and ADC maps in the evaluation of placental changes during gestation.
OBJECTIVE
To establish if a correlation exists between apparent diffusion coefficient (ADC) values, obtained by diffusion-weighted imaging (DWI), and placental aging.


METHODS
The study is divided into a retrospective phase and a prospective one.In the first phase, 145 pregnant women underwent fetal magnetic resonance imaging (MRI) for suspected disorders in several organs. We performed DWI (b value 0, 200 and 700 s/mm(2)) in all the fetuses, evaluating the patients in whom the whole placenta was visible.In the prospective phase, 50 women (52 fetuses) underwent MRI. We performed, in the same patient, two echo-planar sequences with b values of 0, 200 and 700, and 50, 200 and 700 s/mm(2), including the whole placenta.The ADC maps were calculated for all fetuses, divided into three groups based on gestational age (GA): group I: 20-26 weeks' gestation, II: 27-33, III: 34-40.


RESULTS
In the retrospective phase, ADC values had a range from 1 to 2.4 mm(2)/s, showing a significant correlation between ADC values and GA.ADC values obtained by DWI with b value 0, 200 and 700 s/mm(2) had a range from 0.8 to 2.5 mm(2)/s, with an inverse correlation between ADC values and GA, whereas the ADC values with b value 50, 200 and 700 s/mm(2) did not show any statistical correlation (range: 1.5-1.7 mm(2)/s).


CONCLUSIONS
DWI with ADC maps can not be considered markers for placental aging because they are affected by perfusional and circulatory motion.
Department of Radiological Sciences, Umberto I Hospital, Sapienza University of Rome, Rome, Italy.
Lucia
L
Manganaro
Francesca
F
Fierro
Alessandra
A
Tomei
Laura
L
La Barbera
Sara
S
Savelli
Paolo
P
Sollazzo
Maria Eleonora
ME
Sergi
Valeria
V
Vinci
Laura
L
Ballesio
Mario
M
Marini
D000293:Adolescent; D000328:Adult; D004058:Diffusion; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods* / Q000592:standards; D005240:Feasibility Studies; D005260:Female; D005865:Gestational Age; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008962:Models, Theoretical; D010920:Placenta / Q000000981:diagnostic imaging* / Q000502:physiology*; D011247:Pregnancy; D011296:Prenatal Diagnosis / Q000379:methods; D011859:Radiography; D012016:Reference Values; D012189:Retrospective Studies; D055815:Young Adult