| 25 Février 2016
Pediatric and Developmental Pathology
– The distal villous hypoplasia (DVH) pattern is connected to fetal
growth restriction of the placenta, potentially offering a new approach
to placental evaluation. As corresponding author David Grynspan
explains, “Growth restriction of a fetus in pregnancy has health
implications for the fetus that could be lifelong—and for the mother in
subsequent pregnancies. Aside from its clinical significance, our study
helps shed light on the deeper mathematical aesthetic behind humanity’s
unique mother–child interface.” In the article
“The Placental Distal Villous Hypoplasia Pattern: Interobserver
Agreement and Automated Fractal Dimension as an Objective Metric,” the
writers propose that, because the DVH pattern seems to be simpler than
comparably developed placental villi, DVH could also correlate to lower
fractal dimension. The study aimed to assess interobserver agreement
connected to the DVH pattern among skilled pathologists and to conclude
whether that pathologist classification of DVH also correlated with
fractal dimension. Grynspan
notes that “placental exam until now has not been as helpful as we
hoped, in part because it involves looking at two dimensional cross
sections of a tree-like structure. In our study—by using the mathematics
of fractals—we are able to find an objective quantitative measure that
tells us how complex a placenta’s branching pattern is. Just as trees
growing in low light condition are sparser—sacrificing lushness for
function—so too is the placenta in restricted conditions.” To
conduct the study, one expert pathologist created a set of 30 digital
images of placental parenchyma at 4x magnification. The images were
graded for the DVH pattern at no, mild to moderate, and severe levels of
DVH. Four additional international pathologists were shown the images
in a randomly sorted array and graded them similarly for DVH. Using the
data, weighted kappas were calculated, and fractal dimension in each
image was calculated using the box counting method. Ultimately,
the study’s findings imply that fractal dimension could offer a new
approach to objective and quantitative evaluation of the DVH pattern in
placental tissue. Grynspan explains that “the research is important
because, for a long time, we have believed that the placenta should
allow us to differentiate fetuses that are growth-restricted from those
that are just smaller as part of the normal spectrum.” While further
studies are needed, this one suggests that fractal dimension could offer
solid proof of villous abnormalities in placental pathology. The
writers recommend that future research attempt to connect fractal
dimension of DVH with measurable outcomes that affect mother and child.
