Strengths and Limitations
In the study, MRI clearly showed the placental morphology, velamentous
vessels position and courses of potential vasa previa. That implied the
reasons why ultrasonography was unable to reach conclusive diagnosis of
vasa previa occasionally. But limited by the low rate of vasa previa
cases in pregnancies, the current study is not a large sample randomized
controlled trial, so bias can not be fully avoided.
The prevalence rate of vasa previa is relatively low, and
ultrasonography is most often used and commonly able to detect the
disease. Thus the cases, in which ultrasound cannot reach conclusive
diagnosis for vasa previa, will be even fewer. So future long term
researches enrolling more additional similar cases are needed to check
MRI sensitivity and specificity in this field, though MRI already showed
satisfied results in the current study. As MRI is not commonly applied
in diagnosing vasa previa, future researches also need strong support
from patients, ultrasonology and radiology specialists.