Transvaginal ultrasonography combined with color velocity imaging and pulsed Doppler to detect residual trophoblastic tissue
The value of transvaginal B-mode ultrasonography combined with color velocity imaging and pulsed Doppler to detect retained trophoblastic tissue was evaluated prospectively in a series of 40 patients with postpartum (n = 15) or postabortion (n = 25) bleeding.
Color velocity imaging was used to identify color-coded blood flow signals within myometrium and/or endometrium. Flow was subjectively quantified as absent, scanty or abundant. Pulsed Doppler was used to assess blood flow impedance by calculating the resistance index.
The presence of abundant flow with a lowest resistance index of less than 0.45 was considered as suspicious of residual trophoblastic tissue. Twenty-two (55%) out of the 40 patients underwent dilatation and curettage and chorionic villi were demonstrated in 15 of these. Eighteen (45%) patients were managed conservatively. None of these patients suffered complications or needed readmission for curettage, and all of them were considered as not having retained tissue. On color pulsed Doppler ultrasound examination, 15 patients had suspected retained tissue; all of these underwent curettage and residual trophoblast was found in 14 (93.3%). Out of 25 patients considered as having no residual tissue on color pulsed Doppler ultrasound examination, seven underwent curettage and chorionic villi were found in one patient (false-negative rate 6.7%) All patients managed conservatively had an unsuspicious scan.
We concluded that transvaginal ultrasonography combined with color velocity imaging and pulsed Doppler could be useful to detect retained trophoblastic tissue and to select patients suitable for conservative management.
CITATION Ultrasound Obstet Gynecol. 1998 Jan;11(1):54-8