Figure 3: Pathological findings
  1. Infarction: Infarctions show collapse of the intervillous space and associated villous aggregation and coagulative necrosis, and over time all nuclear structures disappear. They are accompanied by neutrophil infiltration.
  2. Avascular terminal villi: Villous stromal-vascular karyorrhexis with disappearance of all blood vessels and uniformly fibrotic and vitrified stroma.
  3. Dilatation of stem villi: Dilatation of stem villi is defined as the enlargement of a stem villous vessel > 4 times that of neighboring vessels of similar caliber.
  4. Hyper-vascular terminal villi: At least ≥ 10 blood vessels are found in one terminal or intermediate villus; ≥ 10 of these villi are found in a visual field at 10x; and ≥ 10 of them are found in ≥ 3 random cotyledon sections.
Figure 4: Accuracy of antenatal ultrasound detection of placental pathologic findings
  1. Receiver Operating Characteristic (ROC) curve predicting infarction
  2. ROC curve predicting avascular villi
  3. ROC curve predicting congestion
  4. ROC curve predicting chrangiosis
Figure 5: Superb microvascular imaging findings and pathological findings in case of diffuse small infarctions diagnosed as avascular villi: (a) Avascular villi was suspected because of detection of only scatter without villous tree. (b) Diffuse small infarctions are detected pathologically.