Yoshimitsu Ohgiya MD, Presenter: Nothing to Disclose

Hiroshi Nobusawa MD, PhD, Abstract Co-Author: Nothing to Disclose

Noritaka Seino, Abstract Co-Author: Nothing to Disclose

Jumpei Suyama MD, PhD, Abstract Co-Author: Nothing to Disclose

Masanori Hirose MD, Abstract Co-Author: Nothing to Disclose

Takehiko Gokan MD, Abstract Co-Author: Nothing to Disclose

To evaluate morphologic and signal intensity (SI) changes of placental insufficiency on MRI and to assess value of morphologic changes and decreased flow voids (FVs) on T2-weighted RARE imaging for diagnosing placental insufficiency.

Fifty singleton fetuses with abnormal findings at US underwent MRI that included T2-weighted half-Fourier RARE imaging and T1-weighted FLASH imaging using a 1.5 T MR scanner. Placental insufficiency was diagnosed if fetal weight estimated with US was below the 5th percentile. Histopathologic examinations were available in all placentas. Placental thicknesses, placental areas, placental volumes, placental SI, and amniotic fluid SI were measured on MR images. Two radiologists reviewed T2-weighted RARE images for globular appearances of the placentas and FVs between the uterus and the placenta. A thickened appearance or no tapering edges of the placenta was diagnosed as positive signs of a globular appearance. None or decreased size and number of FVs between the uterus and the placenta was diagnosed as positive signs of decreased FVs. The t tests and McNemar's tests were used at 5% levels of significance.

Twenty-five of the 50 pregnancies were categorized as having an insufficient placenta. The mean placental thicknesses with placental insufficiency were larger than that without placental insufficiency (p < 0.01). The mean placental areas and the mean placenta to amniotic fluid signal intensity ratio (SIR) with placental insufficiency were smaller than those without placental insufficiency (p < 0.01). There was no significant difference in placental volumes. The sensitivity, specificity, and accuracy were as follows; 76.0%, 80.0%, and 78.0% with globular appearances, 52.0%, 88.0%, and 70.0% with decreased FVs, 88.0%, 76.0%, and 82.0% with globular appearances plus decreased FVs. There is a significant difference in sensitivity between decreased FVs and globular appearances plus decreased FVs.

Placental insufficiency is associated with placental areas, placental thicknesses, and placenta to amniotic fluid SIR. Evaluating FVs on T2-weighted RARE images can be useful for detecting placental insufficiency, particularly in placentas without globular appearances on MRI.

T2-weighted RARE imaging can demonstrate morphologic changes of the placentas and decreased flow voids between the uterus and the placenta in placental insufficiency.

Ohgiya, Y, Nobusawa, H, Seino, N, Suyama, J, Hirose, M, Gokan, T, Placental MR Imaging in Fetuses with Placental Insufficiency.  Radiological Society of North America 2013 Scientific Assembly and Annual Meeting, December 1 - December 6, 2013 ,Chicago IL. http://archive.rsna.org/2013/13013554.html