Placenta percreta post evacuation: an unusual uterine mass on MRI

Placental vascularity and resorption delay after conservative management of invasive placenta: MR imaging evaluation

OBJECTIVES

To assess the potential of magnetic resonance (MR) imaging in evaluating placental vascularity and predicting placental resorption delay after conservative management of invasive placenta.

METHODS

MR examinations of 23 women with conservative management of invasive placenta were reviewed. Twelve women had pelvic embolisation because of postpartum haemorrhage (Group 1) and 11 had no embolisation (Group 2). Comparisons between the two groups were made with respect to the delay for complete placental resorption at follow-up MR imaging and degree of placental vascularity 24 h after delivery on early (30s) and late (180 s) phase of dynamic gadolinium chelate-enhanced MR imaging.

RESULTS

The median delay for complete placental resorption in the cohort study was 21.1 weeks (range, 1-111 weeks). In Group 1, the median delay for complete placental resorption was shorter than in Group 2 (17 vs 32 weeks) (P = 0.036). Decreased placental vascularity on the early phase was observed in Group 1 by comparison with Group 2 (P = 0.003). Significant correlation was found between the degree of vascularity on early phase of dynamic MR imaging and the delay for complete placental resorption (r = 0.693; P < 0.001).

CONCLUSIONS

MR imaging provides useful information after conservative management of invasive placenta and may help predict delay for complete placental resorption.

Magnetic resonance imagining (MRI) and serial beta-human chorionic gonadotrophin (beta-hCG) follow up for placenta percreta

BACKGROUND

Placenta percreta is a rare obstetric condition associated with life-threatening hemorrhage. MR imaging has a role in prenatal diagnosis of these cases. However, its role in the postnatal diagnosis and in the follow up yet to be established.

CASE

A 33-year-old patient has adherent placenta following spontaneous delivery at 37 weeks gestation. MR imaging diagnosed placenta percreta. Intramuscular methotrexate treatment was initiated with follow up with serial beta-human chorionic gonadotrophin (beta-hCG). In spite of dropping of the level of beta-hCG, the trophoblastic tissue was still present 6 weeks postnatally where the patient complained of vaginal bleeding where she opted to abdominal hysterectomy.

CONCLUSION

Patients who are suitable for non-surgical therapy, T2-weighted MR imaging may, in conjunction with serial beta-hCG assays, provide an alternative treatment modality for cases of placenta percreta.

Imaging of vascular disorders of the female pelvis

Clinical presentation of vascular disorders of female pelvis including placental adhesion, retained product of conception, ovarian venous thrombosis, varices, torsion and haemorrhagic infarct of ovary is often non-specific. Because of its availability, safety, and cost-effectiveness, ultrasound is the first investigation of choice. Computed tomography and MRI clearly depict the pelvic and retroperitoneal anatomy. This pictorial essay illustrates the complementary role of US, CT, and MRI in diagnosing vascular disorders of female pelvis.

Postpartum MR diagnosis of retained placenta accreta

Retained placenta accreta can cause catastrophic postpartum hemorrhage. This study aims to determine whether MR imaging can differentiate retained placenta accreta from postpartum hemorrhage caused by other conditions. Fourteen cases suspicious for retained placenta were examined with MR imaging. Signal intensity, the enhancing pattern of uterine contents, and flow voids within the myometrium were retrospectively studied. As hysterectomy was performed in only two cases, final diagnosis was based on clinical outcome and analysis of uterine contents. Final diagnoses were retained placenta accreta in seven cases, retained normally attached placenta in four, hematoma in two, and placental site trophoblastic tumor (PSTT) in one. All seven cases with placenta accreta had a very hyperintense area on T2-weighted images, showing transient early enhancement. None demonstrated delayed strong enhancement around the hyperintense area. In two cases with retained normally attached placenta and in both with hematomas, there were no hyperintense areas on T2-weighted images. Of these, only one showed transient early enhancement. Flow voids were observed in four cases with placenta accreta, one with normally attached placenta, and the case with PSTT. A markedly hyperintense area on T2-weighted images and transient early enhancement without delayed strong enhancement between the mass and the myometrium can indicate retained placenta accreta.

MR imaging of retained products of conception

OBJECTIVE

The objective of this article is to describe the MR imaging appearances of retained products of conception.

CONCLUSION

Retained products of conception appear on MR imaging as an intracavitary uterine soft-tissue mass with variable amounts of enhancing tissue and variable degrees of myometrial thinning and obliteration of the junctional zone. These findings should not be misinterpreted as indicating gestational trophoblastic disease, particularly in the setting of a postpartum patient with a normal or minimally elevated beta-human chorionic gonadotropin level. MR imaging may also be helpful in showing anatomic variants that hinder successful instrumentation of the uterine cavity in patients with suspected retained products of conception.

Fast MR imaging in obstetrics

Ultrasonography (US) is the initial imaging modality of choice for evaluation of patients in obstetrics. However, the results of US are not always sufficient. Magnetic resonance (MR) imaging, which uses no ionizing radiation, may be an ideal method for further evaluation. Although MR imaging is not recommended during the first trimester and use of contrast material is not recommended in pregnant patients, fast MR imaging is useful in various obstetric settings and can provide more specific information with excellent tissue contrast and multiplanar views. In pregnant patients with acute conditions, various diseases (eg, red degeneration of a uterine leiomyoma) may be diagnosed. MR imaging allows characterization of pelvic masses discovered during pregnancy and diagnosis of postpartum complications (eg, abscess, hematoma, ovarian vein thrombosis). In pregnant patients with hydronephrosis, MR urography can demonstrate the site of obstruction and the cause (eg, a ureteral stone). MR pelvimetry may be beneficial in cases of breech presentation. Contrast material-enhanced dynamic MR imaging allows one to evaluate the vascularity of a placental polyp, detect the viable component of a gestational trophoblastic tumor, and diagnose a uterine arteriovenous malformation. MR imaging enables diagnosis of rare forms of ectopic pregnancy and early diagnosis of ectopic pregnancy.

Placenta percreta--two cases and review of the literature

Two cases of placenta pecreta confirmed histologically were treated conservatively with retention of the uterus. Both later went on to have successful pregnancies.

Placenta accreta: MRI antenatal diagnosis and surgical correlation

We describe a case of a placenta previa accreta that was diagnosed antenatally by MRI with subsequent surgical confirmation. We show the advantages of ultrafast MRI single shot (SS) fast spin echo (FSE) techniques for accurate diagnosis with minimal scan time and fetal motion artifacts.