Abnormal placentation: the role of MRI in diagnosis and therapeutic planning

Combined Efficacy of Balloon Occlusion and Uterine Artery Embolization on Coagulation Function in Patients with High-Risk Placenta Previa during Cesarean Section

PURPOSE

The present study was performed in order to investigate the conbined effect of balloon occlusion and uterine artery embolization on coagulation function in patients with high-risk placenta previa during cesarean section.

METHODS

There involved a total of 38 patients with high-risk placenta previa undergoing cesarean section in our hospital from August 2019 to January 2021. The patients enrolled were randomly divided into study group (19 cases, receiving balloon occlusion combined with uterine artery embolization) and control group (19 cases, receiving conventional cesarean section). The operation time, intraoperative blood loss, plasma injection volume and hospital stay of the two groups were recorded. Moreover, the postoperative coagulation function indexes, including thrombin time (TT), fibrinogen (FBI), activated partial thromboplastin time (APTT) and prothrombin time (PT), were monitored and compared. Neonatal Apgar score and postoperative complications of the two groups were regarded as parameters for comparison.

RESULTS

The intraoperative blood loss, plasma injection volume and hospital stay of the study group were significantly lower compared with the control group (P < 0.05), whereas the operation time of the two groups was comparable (P > 0.05). Compared with the control group, the levels of TT, APTT and PT were lower while the level of FBI was higher in the study group (P < 0.05). The Apgar 1-min and 5-min scores of newborns were compared between the two groups (P > 0.05). However, the incidence of postoperative complications in the study group showed evidently lower outcomes compared with the control group (P < 0.05).

CONCLUSION

The combined approach of balloon occlusion and uterine artery embolization offered potential for improving the coagulation function of patients with high-risk placenta previa during cesarean section. In addition, the approach reduced the amount of blood loss and plasma injection, shortened the length of hospital stay, which was believed available for wide clinical application.

Role of Ultrasound and MRI in Diagnosis of Severe Placenta Accreta Spectrum Disorder: An Intraindividual Assessment With Emphasis on Placental Bulge

Background: The placental bulge sign (focal area of myometrial-placental bulging beyond the normal uterine contour) on ultrasound (US) or MRI is postulated to represent deeper venous invasion in placental accreta spectrum (PAS) disorder and may represent severe PAS. Objective: To evaluate the diagnostic performance and interobserver agreement of US and MRI features for diagnosis of severe PAS, with an emphasis on the placental bulge sign. Method: This retrospective study included 62 pregnant women (mean age 33.2±5.5 years) with clinically suspected PAS who underwent both US and MRI. Five independent reviewers (two maternal-fetal medicine specialists for US; three abdominal radiologists for MRI) independently reviewed images for the given modality, blinded to the final diagnosis, and recorded presence of a range of findings (nine on US, eight on MRI) including placental bulge. Intraoperative and pathologic findings were used to separate patients into those with and without severe PAS, based on International Federation of Gynaecology and Obstetrics classification. Diagnostic performance of US and MRI findings for severe PAS were evaluated; multivariable logistic regression was performed; and interobserver agreement was assessed. Results: A total of 58.1% (36/62) of patients had severe PAS. On US, the finding with highest accuracy for severe PAS was placental bulge (85.5%), which was associated with sensitivity of 91.7% and specificity of 76.9%. On MRI, the finding with highest accuracy was also placental bulge (90.3%), which was associated with sensitivity of 94.4% and specificity of 84.6%. At multivariable regression, placental bulge was an independent predictor of severe PAS for US [odds ratio (OR)=8.94; p=.02] and MRI (OR=45.67; p=.003). Interobserver agreement analysis demonstrated kappa for placental bulge of 0.48 for MRI and 0.40 for US. Given wide 95% CIs, differences among features for a given modality as well as differences between modalities were not statistically significant. Conclusion: The findings suggest strong performance of placental bulge in diagnosing severe PAS on both US and MRI, with potentially relatively stronger performance on MRI. Nonetheless, interobserver agreement remains suboptimal on both modalities. Clinical impact: Accurate prenatal diagnosis of severe PAS by imaging could help guide maternal counseling and selection between hysterectomy and uterine-preserving surgery.

CIRSE standards of practice on gynaecological and obstetric haemorrhage

This CIRSE Standards of Practice document provides best practices for obstetric haemorrhage embolisation (OHE) in the management of postpartum haemorrhage (PPH). The document is aimed at interventional radiologists involved in treating postpartum haemorrhage, and has been developed by a writing group established by the CIRSE Standards of Practice Committee.

CIRSE Standards of Practice documents are not clinical practice guidelines and do not intend to impose a standard of care, rather provide reasonable approaches to and best practices for specific interventional radiology treatments and techniques.

Long-term follow-up of abdominal aortic balloon occlusion for the treatment of pernicious placenta previa with placenta accreta

OBJECTIVE

To evaluate the efficacy and safety of balloon occlusion of the abdominal aorta for the treatment of pernicious placenta previa with placenta accreta.

METHODS

The clinical data of 623 patients with pernicious placenta previa combined with placenta accrete, who were admitted to our hospital from January 2013 to January 2019 were retrospectively analyzed. All patients underwent abdominal aortic balloon occlusion combined with cesarean section, and 78 patients underwent sequential bilateral uterine artery embolization. We analyzed the operation time, intraoperative blood loss, blood transfusion volume, intraoperative and postoperative complications, fetal radiation exposure time and dose, and the Apgar score of the newborns. We also performed other evaluations to ascertain the efficacy and safety of abdominal aortic balloon occlusion treatment for dangerous placenta previa with placenta accrete.

RESULTS

Of the 623 patients, 545 underwent only abdominal aortic balloon occlusion, and 78 underwent uterine artery embolization due to intraoperative or postoperative bleeding. The uterus was successfully preserved in all patients. Except for five cases of right lower extremity arterial thrombosis, the remaining patients did not have postoperative lower extremity arteriovenous thrombosis, renal insufficiency, late postpartum hemorrhage, ectopic embolism, spinal cord or peripheral nerve damage, pelvic infection, or other serious complications. The mean operative time was 65.3 (±14.5) min. The mean intraoperative blood loss was620 (±570) ml. Ninety-six patients (15.4%, 96/623) were treated with blood transfusion, and the average amount of blood transfused was 750 (±400) ml. The average number of hospitalization days was 6.8 (±3.4) days, the average time of fetal ray exposure was 5.2 (±1.6) s, and the average radiation dose was 4.1 (±2.7) mGy. The neonatal Apgar score, was 8.4 (±0.6) points at 1 ​min, and 9.6 (±0.4) points at 5 ​min. In the follow-up to May 31, 2019, 29 patients were lost to follow-up, 96 were lactating, and 498 were menstruating. Except for the cases lost to follow-up, the remaining 596 surviving newborns (including 2 twins) showed no abnormalities at the 42-day postnatal outpatient follow-up examination.

CONCLUSION

Balloon occlusion of the abdominal aorta is a safe and effective method for the treatment of pernicious placenta previa with placenta accreta.

Application of abdominal aortic balloon occlusion followed by uterine artery embolization for the treatment of pernicious placenta previa complicated with placenta accreta during cesarean section

OBJECTIVE

This study aimed to investigate the clinical effects of abdominal aortic balloon occlusion followed by uterine artery embolization for the treatment of pernicious placenta previa complicated with placenta accreta during cesarean section.

METHODS

We performed a retrospective analysis of the clinical data for 623 patients who experienced pernicious placenta previa complicated with placenta accreta and received treatment in our hospital from January 2013 to January 2019. All patients underwent abdominal aortic balloon occlusion before their cesarean section. Seventy-eight patients received bilateral uterine artery embolization, and among them, placenta accreta was found at the opening of the cervix in 13 patients. Due to suturing difficulty after the removal of the placenta, gauze packing was used to temporarily compress the hemorrhage. As soon as the uterus was sutured, emergent bilateral uterine artery embolization was performed. Active bleeding was noted in the remaining 65 patients when the lower part of the uterus was pressed after the placenta was removed and the uterus was sutured, therefor, bilateral uterine artery embolization was performed urgently.

RESULTS

Of the 623 patients, 545 patients underwent only abdominal aortic balloon occlusion and 78 patients underwent additional emergent bilateral uterine artery embolization due to hemorrhaging during or after their cesarean section. No hysterectomies were performed. In the 78 patients, the amount of bleeding was 800-3,200 ml with an average of 1,650 ml during the operation; the volume of blood transfused was 360-1,750 ml (average: 960 ml). The fetal fluoroscopy time was 3-8 s (average: 5 s). The dose of radiation exposure was (4.2 ± 2.9) mGy. Fetal appearance, pulse, grimace, activity, and respiration (Apgar) score were normal. No serious complications were observed during or after the operation in the follow-up visits. Conclusion: For patients with pernicious placenta previa complicated with placenta accreta who experience active bleeding after cesarean section and abdominal aortic balloon occlusion, bilateral uterine artery embolization can effectively reduce blood loss and requirement of blood transfusion during the operation, and lowers the risk of hysterectomy.

MRI prognosticators for adverse maternal and neonatal clinical outcome in patients at high risk for placenta accreta spectrum (PAS) disorders

BACKGROUND

Placenta accreta spectrum (PAS) disorders may be associated with significant mortality and morbidity for both mother and fetus.

PURPOSE/HYPOTHESIS

To identify MRI risk factors for poor peripartum outcome in gravid patients at risk for PAS.

STUDY TYPE

Prospective.

POPULATION

One hundred gravid women (mean age: 34.9 years) at third trimester, with placenta previa.

FIELD STRENGTH/SEQUENCE

T₂ -SSTSE (single-shot turbo spin echo), T₂ -TSE, T₁ -TSEFS (TSE images with fat-suppression) at 1.5T.

ASSESSMENT

Fifteen MRI features considered indicative of PAS were recorded by three radiologists and were tested for any association with the following adverse peripartum maternal and neonatal events: increased operation time, profound blood loss, hysterectomy, bladder repair, ICU admission, prematurity, low birthweight, and 5-minute APGAR score <7.

STATISTICAL TESTS

Kappa (K) coefficients were computed as a measure of agreement between intraoperative information/histology and MRI results as well as for interobserver agreement; chi-square and Fisher's exact tests were used to explore the association of the MRI signs with clinical complications. A score was calculated by adding all recorded MRI signs and its predictive ability was tested using receiver operating characteristic (ROC) analysis, against all complications, separately; odds ratios (ORs) for optimal cutoffs were determined with logistic regression analysis.

RESULTS

There was excellent agreement (K >0.75, P < 0.001) between MRI and intraoperative findings for invasive placenta, bladder and parametrial involvement. Intraplacental T₂ dark bands, myometrial disruption, uterine bulge, and hypervascularity at the utero-placental interface or parametrium, showed significant association (P < 0.005) with poor clinical outcome for both mother and fetus. The MRI score showed significant predictive ability for each adverse maternal event (area under the curve [AUC]: 0.85-0.97, P < 0.001). The presence of ≥3 MRI signs was the cutoff point for a complicated delivery (OR: 19.08, 95% confidence interval [CI]: 6.05-60.13) and ≥6 MRI signs was the cutoff point for massive bleeding (OR: 90.93, 95% CI: 11.3-729.23), hysterectomy (OR: 72.5, 95% CI: 17.9-293.7), or extensive bladder repair (OR: 58.74, 95% CI: 7.35-469.32). The MRI score was not significant for predicting adverse neonatal events including preterm delivery (P = 0.558), low birthweight (P = 0.097), and 5-minute Apgar score (P = 0.078).

DATA CONCLUSION

Preoperative identification of specific MRI features may predict peripartum course in high-risk patients for PAS.

LEVEL OF EVIDENCE

1 Technical Efficacy: Stage 5 J. Magn. Reson. Imaging 2019;50:602-618.