Three-dimensional power Doppler imaging of uterine artery pseudoaneurysm treated unsuccessfully with selective embolization.

A 24-year-old primigravida underwent a scheduled Cesarean delivery at 39 weeks' gestation for breech presentation. Five weeks after the Cesarean section she presented to our emergency department with sudden onset of heavy vaginal bleeding and abdominal pain. Transvaginal ultrasound examination (Accuvix XQ, Medison Corp, Seoul, Korea) showed a hypoechoic area, measuring 14.4 × 8.8 mm, located at the level of the lower uterine segment, adjacent to the Cesarean suture, which involved the majority of the myometrial wall on the right side of the uterus (Figure 1a). Color Doppler sonography confirmed bidirectional systolic and diastolic flow (peak systolic velocity, 0.70 m/s; resistance index, 0.53) within the area, which appeared to be connected to the right uterine artery, findings consistent with a pseudoaneurysm of this vessel (Figure 1b). The patient underwent pelvic angiography and embolization of the pseudoaneurysm. Selective hypogastric arteriography using a 5-F cobra shaped catheter was performed and multiple metallic coils of 3 mm in diameter were deployed across the origin of the pseudoaneurysm from the uterine artery, followed by pledgets of gelatine sponge. Repeat ultrasound examination performed 2 days later showed a complex area of mixed echogenicity, consistent with thrombotic change within the original vascular lesion (Figure 1c) with no blood flow evident on Doppler assessment. The woman made an uneventful recovery following the embolization, despite daily Doppler examinations demonstrating a slow return of blood flow into the pseudoaneurysm. (a) Transvaginal gray-scale ultrasound image showing an anechoic area at the level of the lower uterine segment, adjacent to the Cesarean suture, which involved the majority of the myometrial wall on the right side of the uterus. (b) Color Doppler image showing turbulent arterial flow into the anechoic area consistent with a pseudoaneurysm of the right uterine artery. (c) Color Doppler image of the same region after the first embolization procedure. No flow was detected, a finding consistent with thrombosis of the original vascular lesion. Revascularization was further examined by three-dimensional power Doppler angiography (3D-PDA) and the See-Thru™ mode, which suggested the vascular lesion of the uterine artery involved the parametrium and the right uterine wall at the edge of the uterine cavity (Figure 2a,c). Ten days after the angiographic procedure the patient underwent a second selective bilateral hypogastric arteriographic assessment, which confirmed the 3D-power Doppler findings (Figure 2b). A second embolization was performed and the patient was subsequently discharged with no vaginal bleeding (her hemoglobin at this stage was 10.6 g/dL). Five days later, profuse vaginal hemorrhage began. Estimated blood loss at re-admission was 2.5–3 L. She was hypotensive and her hemoglobin had dropped to 7 g/dL. The emergency team performed an exploratory laparotomy to try to preserve her fertility but her life-threatening condition (risk of disseminated intravascular coagulopathy) led to a total abdominal hysterectomy. Histopathological findings confirmed a pseudoaneurysm of the right uterine artery with involvement of the whole myometrium (Figure 2d). (a) Three-dimensional (3D) power Doppler angiographic reconstruction of the pseudoaneurysm. (b) X-ray angiography confirming revascularization of the pseudoaneurysm. (c) 3D power Doppler rendering (coronal view) using the See-Thru mode, showing the parametrial location of the pseudoaneurysm at the right edge of the uterine cavity (arrows). (d) Photograph of the macroscopic surgical sample, showing transverse section of the uterine corpus at the level of the isthmus. The pseudoaneurysm (arrows) was at the right edge of the Cesarean suture, involved most of the uterine wall and communicated with both the uterine cavity and parametrial tissue. Pseudoaneurysm (or false aneurysm) of the uterine artery is a rare cause of puerperial hemorrhage1-9. When a punctured or lacerated artery does not seal completely, the resulting hematoma dissects the adjacent tissues. Central retraction of the hematoma leaves a cavity with a direct connection to the damaged artery2, 10. Contrast angiography is considered the gold standard technique for diagnosing pseudoaneurysms, however, Doppler ultrasonography has been reported to have high sensitivity and specificity for this diagnosis9. In our case, revascularization of the lesion was seen on color Doppler imaging, and 3D-PDA demonstrated the precise angioarchitecture, which was confirmed by X-ray angiography. Reconstruction of a 3D power Doppler dataset provides the user with different and additional views from those evident with conventional two-dimensional imaging, improving spatial orientation and allowing a more precise analysis of the vascular anatomy. In this case, post-processing of the stored volume using the See-Thru rendering mode enabled us to confirm the location of the vascular lesion within the uterine wall, and the coronal view showed that the lesion reached the edge of the uterine cavity and extended into the uterine wall at the level of the right parametrium (Figure 2c). X-ray angiography cannot precisely locate the lesion within the uterine cavity, parametria or broad ligament because this imaging mode cannot distinguish between these soft tissue structures. B-mode and color Doppler ultrasound remain the primary tools for the diagnosis of vascular anomalies in patients presenting with heavy vaginal bleeding in the puerperium. However, 3D-PDA allows the user to define the dimensions of any lesion, demonstrates complex flow patterns and confirms the relationship between the viscera and the vascular lesion. The impact of this technology in the clinical management of postpartum hemorrhage has yet to be ascertained.