GTD (most commonly choriocarcinoma after third trimester delivery) is a rare cause of delayed PPH and appears as a heterogeneous hypervascular intrauterine mass, often with central necrosis, indistinguishable from RPOC, except in cases of invasion of adjacent organs or distant metastasis [14]. CTA Abdomen and Pelvis Persistent hemorrhage after empiric embolization is an indication for CTA [12]. Active extravasation is seen in 41% to 74% cases of PPH on CTA [17] and multiphasic CT, including a noncontrast, arterial, and portal venous phases, has excellent accuracy of 97% [18] for detection of the site of active extravasation, similar to that of gastrointestinal hemorrhage [17,18]. CTA can be falsely positive because of dilated tortuous hypertrophic uterine arteries mimicking extravasation and be falsely negative in atony because of slow intermittent hemorrhage [12,18]. Serpiginous myometrial vessels and prominent parametrial vessels can be a sign of VUA [19], whereas the presence of a pseudoaneurysmal sac is a more specific finding [14,20,21]. CTA can also identify and localize the feeding arteries of AVM for treatment planning [14]. However, CTA cannot reliably distinguish acquired VUA from failure of obliteration/subinvolution of the placental bed vessels, assess its severity, or need for intervention [19]. MRI Pelvis In clinically suspected endometritis, MRI can identify associated findings such as abscess or infected hematoma that may require drainage and other complications such as ovarian vein thrombosis [14]. RPOC can be seen as a variably enhancing intracavitory mass with variable degree of myometrial thinning [13,14]. Patients with difficult vaginal delivery without large palpable hematoma may benefit from noncontrast MRI to identify deep-seated pelvic hematomas, which depending on the time since delivery may demonstrate variable T1 and T2 signal characteristics [14,23] and a low T2 signal rim after >2 weeks because of hemosiderin deposition.
Postpartum Hemorrhage. GTD (most commonly choriocarcinoma after third trimester delivery) is a rare cause of delayed PPH and appears as a heterogeneous hypervascular intrauterine mass, often with central necrosis, indistinguishable from RPOC, except in cases of invasion of adjacent organs or distant metastasis [14]. CTA Abdomen and Pelvis Persistent hemorrhage after empiric embolization is an indication for CTA [12]. Active extravasation is seen in 41% to 74% cases of PPH on CTA [17] and multiphasic CT, including a noncontrast, arterial, and portal venous phases, has excellent accuracy of 97% [18] for detection of the site of active extravasation, similar to that of gastrointestinal hemorrhage [17,18]. CTA can be falsely positive because of dilated tortuous hypertrophic uterine arteries mimicking extravasation and be falsely negative in atony because of slow intermittent hemorrhage [12,18]. Serpiginous myometrial vessels and prominent parametrial vessels can be a sign of VUA [19], whereas the presence of a pseudoaneurysmal sac is a more specific finding [14,20,21]. CTA can also identify and localize the feeding arteries of AVM for treatment planning [14]. However, CTA cannot reliably distinguish acquired VUA from failure of obliteration/subinvolution of the placental bed vessels, assess its severity, or need for intervention [19]. MRI Pelvis In clinically suspected endometritis, MRI can identify associated findings such as abscess or infected hematoma that may require drainage and other complications such as ovarian vein thrombosis [14]. RPOC can be seen as a variably enhancing intracavitory mass with variable degree of myometrial thinning [13,14]. Patients with difficult vaginal delivery without large palpable hematoma may benefit from noncontrast MRI to identify deep-seated pelvic hematomas, which depending on the time since delivery may demonstrate variable T1 and T2 signal characteristics [14,23] and a low T2 signal rim after >2 weeks because of hemosiderin deposition.