Differential Diagnosis of the Placental Adhesive Disorders

 

Abstract:

The adhesion disorders of the placenta such as placenta accreta and percreta, constitute one of the principal causes of maternal morbidity due to hemorrhage post birth. The placenta previa and the reiterative cesarean are the principal risk factors; in them it is possible to diagnose according to direct and indirect echographic signs. However, in certain occasions the information obtained by the ultrasound is not conclusive, particularly in the differentiation between the placenta accreta and percreta. In these cases, or in those in which additional anatomical information is wanted on the placental invasion, the vascularization or on the actual state of the uterine and vesicle wall, the Nuclear Magnetic Resonance (MRI) provides precise anatomic images. These can be contrasted with gadolinium and distinguish exact limits between the miometrium and the placenta. Thus, the surgery and the proximal vascular control can be planned correctly and adequately. The experience with contrasted MRI in 15 risk patients, the distinctive characteristic of the differential images and the surgical correlation are described in this paper. KEY WORDS: Obstetric MRI, Contrasted MRI, placenta accreta, placenta percreta 

Introduction:

The placental adhesive disorders such as placenta accreta and percreta are frequent causes of serious obstetric hemorrhages and are associated to a high maternal morbidity and mortality. These disorders can be supposed by epidemiological well defined information, such as placenta previa, multiple cesareans, reiterative uterine curettages, uterine infections, etc1. The echography has defined in them direct and indirect signs for their distinction, signs that in occasions allow their diagnoses and in others a strong clinic suspicion 2-3-4-5. However, this information may not be conclusive and additional information must be required.

For them, the Nuclear Magnetic Resonance (MRI) allows to obtain precise anatomic images of the uterine wall, the vascularization, as well as of other pelvic structures. The use of gadolinium – as contrast- provides a net differentiation between the placenta and the uterine wall6 , essential to differentiate the degree of placental invasion.

The radiological distinction between a placenta accreta and percreta practiced by MRI, will allow to establish conducts, approaches and previsions tending to minimize the hematic loss and plan conservative treatments.

Materials and Methods:

FIfteen patients were included in the study between the week 30 and 34 of pregnancy. They presented the following background or signs: 1) total occlusive placenta previa and cesarean (one or multiple) and 2) patients with direct or indirect echographic signs of placenta accreta.

All of them signed an informed agreement for the Resonance, as well as for the contrast administration. This was based in the recommendations and precautions of the FDA (Federal Drug Administration, USA) for this type of procedure in pregnant patients.

The studies were performed with a Resonator Picker EDGE 1.5 Tesla with body coil. All the patients were examined by axial and Sagittal cuts, T1, SE, TE 8, TR 140, FOV 45 to 50, TK 6 to 7, RES 160X256, PS 0.602, FLIP 120º, NA 1. BREATH HOLD 20 Slice and FAT SAT SE, FATSAT, TE 20, TR 500, FOV 45 to 50, TK 6 a 7, RES 128X256, FLIP 90, NA ½ BREATH HOLD. A bolus of Gadolinium (Gadopentetate dimeglumine) was done in them, which was injected quickly in a 0.1 mol/Kp doses. The images were acquired in bolus 45 and 90 seconds after the injection.

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