Magnetic resonance imaging of the female pelvis after Cesarean section: a pictorial review

Abstract

The rate of Cesarean sections (C-sections) in Poland increased from 21.7% in 2001 to 43.85% in 2017 even though the Polish Society of Gynecologists and Obstetricians highlights the negative consequences of C-section for both mother and child and recommends to make every possible effort to reduce its percentage, following the World Health Organization recommendations. There is a long list of possible complications related to the uterine scar after C-section, including uterine scar dehiscence, uterine rupture, abdominal and pelvic adhesions, uterine synechiae, ectopic pregnancy, anomalous location of the placenta, placental invasion, and-rarely-vesicouterine or uterocutaneous fistulas. Ultrasound (US) remains the first-line modality; however, its strong operator- and equipment dependence and other limitations require further investigations in some cases. Magnetic resonance imaging (MRI) is the second-line tool which is supposed to confirm, correct, or complete the sonographic diagnosis thanks to its higher tissue resolution and bigger field of view. This article will discuss the spectrum of C-section complications in the MR image-rich form and will provide a systematic discussion of the possible pathology that can occur, showing comprehensive anatomical insight into the pelvis after C-section thanks to MRI that facilitates clinical decisions.

Keywords: Cesarean section (C-section); Magnetic resonance imaging (MRI); Pelvis.

Fig. 1

A 33-year-old woman 6 days after repeat C-section in 2nd pregnancy. CT is performed due to fever, pain, left costovertebral angle tenderness, and increasing serum level of C-reactive protein (485 mg/l) and procalcitonin (6.7 ng/ml), with a suspicion of renal colic or endometritis. CT revealed gas within the C-section incision in the uterine wall (long arrow) and in the uterine cavity (short arrow), as well as an abscess in front of/under the uterus (thick arrow), shifting the bladder to the left. Two hours later, the patient was operated on, and the abscess was evacuated

Fig. 2

A 34-year-old primigravida primipara 12 days after C-section complicated by dissection of the posterior wall of the uterus. CT in a venous phase shows the normal postoperative appearance of a recent cesarean delivery incision which is hypodense as compared to the intact myometrium (thin arrow)

Fig. 3

MRI of the lumbar-sacral part of the vertebral column in the sagittal plane. a FSE/T2WI. b FSE/T1WI. c STIR image. The study performed for neurological indications 2 weeks after C-section shows the forming scar in the anterior uterine wall, best appreciated as a thick hypointense band on STIR (c arrow). Blood (hyperintense on T1WI and T2WI, suppressed on STIR) and clot (T1- and T2-hypointense, slightly hyperintense on STIR) in a still distended uterine cavity

Fig. 4

MRI of the lumbar-sacral part of the vertebral column in the sagittal plane. a FSE/T2WI. b STIR image. Post-C-section niche, hyperintense against the background of the hypointense myometrium, is shown by the arrows

Fig. 5

Pelvic MRI, FSE/T2WI in sagittal plane: two hyperintense niches after two C-sections (arrows)

Fig. 6

Pelvic MRI, SE/T1WI in the sagittal plane. Hyperintense blood reservoir in the C-section scar defect with intact serosa (arrow), which is isointense to the myometrium

Fig. 7

Pelvic MRI. A 42-year-old woman with a history of three C-sections. a GRE/T2*WI in the coronal plane (skin scar is shown by a thick arrow). b FSE/T1WI and c FSE/T2WI, both in the sagittal plane, depict a huge blood reservoir (T1-hyperintense, of mixed signal intensity on T2WI) with no serosal layer (no hypointense line) on the outer surface (thin white arrows). In pathology report: adenomyosis with autoamputation of the uterine body

Fig. 8

The same patient as in Fig. 5. The arrow points at T2-hypointense adhesion between the uterus and the bladder

Fig. 9

Pelvic MRI in the sagittal plane. FSE/T2WI (a). CUBE/3D/T2WI (b). Thick hypointense adhesions between the abnormally flexed uterus and an anterior abdominal wall

Fig. 10

A 20-year-old woman with a history of synovial sarcoma of the right inguinal region, followed up routinely for oncological indications, 2 months (a FSE/T2WI) and 5 months (b CUBE/3D/T2WI) after C-section. The post-C-section scar is not visible; however, adhesions between the uterus and the bladder wall can be suspected (a) and are confirmed 3 months later, not only by the loss of the fat plane in between but also by the retroflexion of the uterus

Fig. 11

Pelvic MRI consulted for Sports Medicine Centre, Warsaw (images published with permission). FSE/T2WI in the sagittal (a) and axial (c) planes, FSE, T1 fat-saturated image, and the sagittal plane (b). Endometriotic implants on the way of C-section: in the bladder wall (thin arrows) and in the abdominal wall (thick arrows). The lesions are mostly T2-hypointense and T1-isointense, with very tiny foci of hyperintensity

Fig. 12

Pelvic MRI in the sagittal plane, FSE/T2WI (a). Dynamic contrast-enhanced fat-saturated T1 sequence before (b) and after (c) gadolinium administration. Retained products of conception (RPOC) of mixed signal intensity in the C-section niche after treatment with potassium chloride and methotrexate (arrows)

Fig. 13

A 37-year-old woman, 4th pregnancy, 34 GW, history of 2 C-sections. FSE/T2WI (a) and FIESTA/2D image (b), both in sagittal projection, show placenta previa overlying completely the internal cervical os (a, thin arrow). The thick arrow points at the hypointense C-section scar in the abdominal wall (b)

Fig. 14

A 34-year-old woman, 4th pregnancy, dichorionic, diamniotic, 11 GW, history of 2 C-sections. FIESTA/2D image (a) and dynamic contrast-enhanced fat-saturated T1 sequence after gadolinium administration (b), both in sagittal projection, show placenta increta in the post-C-section scar. The urinary bladder did not show abnormalities on cystoscopy

Fig. 15

A 32-year-old woman, 3rd pregnancy, 24 GW, history of a classical C-section 2 years ago and ectopic scar pregnancy 1 year ago. FIESTA/2D image (a), SSFSE/T2WI (b), and FGR/T1WI (c), all in sagittal projection, show elevated vascularity at the placental-myometrial interface—placenta accreta in the post-C-section scar

Fig. 16

The same woman as in Fig. 13. The lack of visibility of the fragment of the bladder wall (thin arrow, a) and blurred placenta, uterus, and abdominal wall interface (thin arrow, b) are highly suggestive of placenta percreta while the bulge indenting the bladder with preserved bladder wall most likely represents the varix (thick arrow, c)