2026, Number 2
Magnetic resonance imaging findings in placental accreta
Full text
10.35366/122618
Language: English/Spanish [Versión en español]
References: 3
Page: 139-141
PDF size: 759.25 Kb.
ABSTRACT
This article describes a clinical case of placenta increta, highlighting the usefulness of magnetic resonance imaging (MRI) for the evaluation of placenta accreta spectrum (PAS). MRI increases the accuracy of evaluation in high-risk patients by evaluating the extent and topography of microinvasion.INTRODUCTION
Placenta accreta spectrum (PAS) is a consequence of the pathological implantation of the placenta into the myometrium.1 Its prenatal identification allows for optimal treatment.
Magnetic resonance imaging (MRI) is indicated when ultrasound evaluation is unequivocal or in patients with risk factors. MRI assists in the evaluation of the posterior placenta, allowing for the planning of cesarean delivery and hysterectomy.2,3
A recent meta-analysis demonstrated that 52% of PAS disorder cases are diagnosed with ultrasound, compared to 73.5% with MRI. Recent meta-analyses show an MRI sensitivity of 94.4% and a specificity of 98.8% in predicting the depth of placental invasion.1
CASE PRESENTATION
A 35-year-old female patient, at 28 weeks of gestation. Obstetric history: three pregnancies, two miscarriages. She was referred for an MRI study due to suspicion of placenta accreta.
The MRI was performed, revealing a placenta located on the left lateral side with the lower edge adjacent to the cervix, findings suggestive of marginal placenta previa, as well as heterogeneity of the placenta, with areas showing loss of the interface with the myometrium.
DISCUSSION
PAS disorders vary in severity, ranging from superficial adherence of the placenta to the myometrium to various degrees of myometrial invasion.1
In placenta accreta, the villi are attached to the myometrium without muscular invasion. In placenta increta, the villi partially invade the myometrium. In placenta percreta, the villi penetrate the entire myometrium to affect adjacent organs.2
The FIGO (International Federation of Gynecology and Obstetrics) classification is based on surgical findings, dividing these disorders into three grades:
Grade 1: adherent placenta.
Grade 2: myoinvasive placenta, with intact serosa.
Grade 3: involvement of the serosa or invasion of pelvic organs, such as the bladder (3b) or even other organs (3c).1
The imaging features on MRI are: dark intraplacental bands on T2, loss of the retroplacental line, abnormal vascularity of the placental bed, uterine-placental bulging, myometrial thinning, focal exophytic mass, and disruption of the bladder wall (Table 1),1 these findings are exemplified in Figures 1 and 2 where the placenta is identified with lobulated edges, heterogeneous, showing linear areas and other punctate areas of low signal within it. There are coexisting zones of loss of interface with the myometrium, as well as localization of the placenta toward the lower border of the internal cervical os.
CONCLUSIONS
This case report highlights the utility of MRI in distinguishing the depth of placental invasion, characterized as placenta increta in our case. This report also highlights the higher sensitivity and specificity of MRI compared to ultrasound, which allows for a reduction in surgical risk and patient morbidity and mortality.
It is important for treating physicians to be familiar with this imaging method. It is a safe method that serves as a complement in complicated cases.
To evaluate PAS, the use of 1.5T or 3T resonators is recommended, with the former being less susceptible to fetal movement. A fast 15-minute protocol is suggested that includes three planes in T2 and an axial sequence in T1, allowing the procedure to be performed efficiently and safely.
REFERENCES
AFFILIATIONS
1 Médico residente de Alta Especialidad en Resonancia Magnética de Cuerpo Completo, Hospital Angeles Pedregal (HAP). Ciudad de México, México.
2 Médico residente de Alta Especialidad en Resonancia Magnética del Sistema Musculoesquelético, HAP. Ciudad de México, México.
3 Médico radiólogo, especialista en Resonancia Magnética. Médico adscrito al Servicio de Resonancia Magnética, HAP. Ciudad de México, México.
4 Médico radiólogo, especialista en Resonancia Magnética. Profesor titular de los cursos de Alta Especialidad de Resonancia Magnética de Cuerpo Completo y Sistema Musculoesquelético, HAP. Ciudad de México, México.
ORCID:
5 0000-0002-9767-900X
6 0000-0001-6793-0171
7 0000-0002-9697-2167
8 0009-0008-3014-0078
9 0009-0004-4033-0183
10 0009-0005-3498-5594
If you wish to consult the supplementary data for this article, please contact editorial.actamedica@saludangeles.mx
CORRESPONDENCE
Cynthia Nalleli González Ramírez. Correo electrónico: cynthia.nglez@gmail.comReceived: 2024-11-07. Accepted: 2025-12-11.