Multidetector CT appearance of the pelvis after vaginal delivery: normal appearances and abnormal acute findings

Abstract

Vaginal delivery is the most commonly performed delivery in the world and accounts for nearly two-thirds of all deliveries in the United States. It is a secure method but may be associated with some acute complications, especially in the immediate postpartum days, which can potentially be fatal for the mother. The most frequent acute complications are hemorrhages/hematomas, uterine rupture, endometritis, retained product of conception (RPOC), ovarian thrombosis and HELLP syndrome (hemolysis, elevated liver enzymes, low platelet count). A first evaluation of the clinical status of the patients is executed by the clinicians who, depending on their experience, perform ultrasonography by themselves and eventually may request further radiologic exams in doubtful cases. Radiologists may play an important role recognizing early postpartum complications and differentiating them from physiologic postoperative findings. In this setting, the use of multidetector computed tomography (MDCT) is important for diagnosis of suspected postpartum complications. The aim of this article is to review the normal and abnormal post vaginal delivery MDCT aspects in order to help the clinical management by preventing misdiagnoses and tailoring the best medical treatments.

Figure 1. a, b

Normal MDCT findings of uterus and uterine arteries in a 34-year-old woman 1 day after spontaneous vaginal delivery. Sagittal contrast-enhanced venous phase MDCT image through the pelvis (a) shows an enlarged uterus with a low-attenuation central area (asterisk) corresponding to intrauterine blood debris and fluid. Intrauterine and intravaginal gas bubbles are also present (white arrows). Note the increased uterine vascularity. Intramural arterial uterine branches appear as dot-like or tubular enhancing structures in the myometrium (arrowheads). Oblique coronal maximum intensity projection (MIP) reformatted image (b) better demonstrates the bilateral myometrial arterial uterine branches and the cervico-vaginal branches of the uterine artery as several tortuous enhancing tubular vessels (black arrows).

Figure 2. a, b

Metrorrhagia in a 30-year-old woman with anemia and vaginal laceration, 1 day after spontaneous vaginal delivery. Sagittal unenhanced MDCT image (a) shows a normal enlarged uterus after vaginal birth with intrauterine amount of fluid and blood debris (asterisk), better demonstrated on sagittal contrast-enhanced venous phase (b). Some gas bubbles can also be seen within the cervical canal (black arrow). Vaginal packing with rolled gauzes is visualized in the vagina (black arrowheads) and it is used to tamponade the bleeding. The bladder is moderately distended by urine and air due to presence of the catheter (white arrows).

Figure 3. a–d

Metrorrhagia in a 36-year-old woman with anemia and blood loss of 500 mL, 2 days after spontaneous vaginal delivery. Axial unenhanced MDCT image (a) and sagittal reformatted MDCT image in venous phase (b) show the uterus with large amounts of blood visible as high-attenuation material within the cervical canal (black asterisk); fresh blood and fluid are also seen as hypodense components in the endometrial cavity (white asterisk). Some intrauterine gas bubbles are also present (white arrow). Axial contrast-enhanced MDCT images in the arterial phase (c) shows punctate foci of intrauterine contrast extravasations within the endometrial cavity increasing in venous phase (d, white arrowhead). Two days after delivery, operative exploration confirmed blood clots and the presence of retained placental tissue.

Figure 4. a–d

Supralevator paravaginal hematoma in a 29-year-old woman, 1 day after spontaneous vaginal delivery, with clinical suspicion of hematoma of vaginal wall. Axial unenhanced MDCT image (a) demonstrates a high-attenuation collection due to fresh blood (white asterisk) located in left paravaginal extraperitoneal space. Axial contrast-enhanced MDCT image in the arterial phase (b) shows active bleeding (black arrowheads). Coronal (c) and oblique sagittal (d) reformatted MDCT images depict the position of the hematoma (white asterisk), contrast extravasation, and the source of the bleeding from the vaginal arteries (black arrowheads). Moreover, the MPR images clearly show the relationship between the hematoma (white asterisk), levator ani muscle (white arrowheads), rectum (black arrows) and vagina (white arrows) which are both contralaterally dislocated. The patient underwent selective arterial embolization.

Figure 5. a–d

Infralevator hematoma in a 39-year-old woman with anemia, 2 days after spontaneous vaginal delivery and surgical procedure of episiorrhaphy. Axial unenhanced MDCT image (a) shows the right perineal hematoma (white asterisk) that contralaterally displaces the inferior part of the vagina (white arrows). Contrast-enhanced arterial (b) and venous (c) phase MDCT images do not demonstrate any active bleeding. Coronal reformatted MDCT image (d) better depicts the position of the hematoma (white asterisk) located in the right paracolpium; note the collapsed and displaced vagina (white arrows).

Figure 6. a–c

Supralevator hematoma in a 34-year-old woman with vaginal delivery complicated by an active pelvic bleeding treated with selective arterial embolization. MRI of the pelvis was performed several weeks after vaginal birth to follow up the extraperitoneal extensive hematoma previously evaluated with a MDCT scan (not shown). Axial T1-weighted fat-suppressed (a) and T2-weighted (b) images show the hematoma located in the right paravesical and paracolpium spaces (white asterisk) with lateral displacement of the bladder (white arrow). Coronal T2-weighted image (c) better shows cranial and lateral displacement of the bladder (white arrow).

Figure 7

Proposed algorithm for the management of postpartum hemorrhage modified from Sierra et al. (11).

Figure 8. a–c

Uterine dehiscence in a 36-year-old woman with pelvic pain, hyperpyrexia and clinical suspicion of uterine perforation, 7 days after spontaneous vaginal delivery. The patient had a previous cesarean delivery. Axial unenhanced (a) and contrast-enhanced MDCT images (b) show the uterus with a defect on the left side of myometrial wall (b, black arrow) associated to a hyperattenuating gas containing fluid collection (white asterisk). Endometrial cavity is distended by fluid, blood debris, and gas bubbles (black asterisk). Coronal reformatted MDCT image in venous phase (c) better depicts the communication between the distended endometrial cavity (black asterisk) and the fluid collection (white asterisk) and its extension in the left extraperitoneal parauterine space. The patient was surgically treated and the uterine dehiscence was confirmed.

Figure 9. a, b

Uterine dehiscence in a 35-year-old woman with unstable vital signs, hematuria and vaginal lacerations, 1 day after spontaneous vaginal delivery. The patient had a previous cesarean delivery. Sagittal reformatted MDCT image in venous phase (a) shows a uterus with a large irregular defect in the anterior myometrial wall at the isthmus (site of prior cesarean section) (black arrows). Anterior to the uterus there is a hyperattenuating fluid collection containing gas bubbles corresponding to a bladder flap hematoma (white asterisk). Posterior bladder wall is irregular with loss of clear border. Hyperattenuating material is visible within the lumen of the bladder (black asterisk) above the catheter. The endometrial cavity is moderately distended and there is increased myometrial vascularity in the fundus at the site of the placental insertion (black arrowheads). Note the vaginal packing with rolled gauzes within the vagina (white arrows). Axial enhanced MDCT image (b) demonstrates a big amount of hemoperitoneum (white arrowheads). Symptoms and images suggested uterine rupture with associated bladder laceration. The patient was surgically treated, and uterine dehiscence and bladder rupture were confirmed.

Figure 10. a, b

Uterine vein thrombosis in a 45-year-old woman with clinical suspicion of chorioamnionitis, 1 day after spontaneous vaginal delivery. Axial contrast-enhanced venous phase MDCT image (a) shows luminal filling defect within the right and left uterine veins (black arrows). In the axial (a) and sagittal (b) contrast-enhanced MDCT images, note the increased dimension of the uterus with an increased myometrial vascularity (black arrowheads). Moderate amount of intrauterine fluid is also present (asterisk).

Figure 11. a–c

Retained products of conception (RPOC) in a 37-year-old woman with endometritis, metrorrhagia and anemia, 2 days after spontaneous vaginal delivery. Axial contrast-enhanced CT image (a) demonstrates a big blood clot (black asterisk) associated to a fluid collection (white asterisk) and air bubbles (white arrows) within the endometrial cavity. Note the fluid collection in the peritoneum (white arrowhead). Oblique coronal (b) and oblique sagittal (c) reformatted MDCT images in venous phase show a high enhancing soft-tissue mass (black arrow) in the anterior myometrial wall, protruding into the endometrial cavity. Note the hypervascularity of the myometrium of the anterior uterine wall (black arrowheads) due to RPOC. Operative exploration confirmed retained placental tissue.