Diagnostic and clinical value of multiparameter magnetic resonance imaging in cesarean scar pregnancy: a comparative study of sequence combinations

Abstract

Background: Cesarean scar pregnancy (CSP) is a special form of ectopic pregnancy that lacks specific clinical manifestations. Artificially induced abortion may lead to severe complications such as massive bleeding and even uterine rupture, posing a threat to the safety of pregnant women. Magnetic resonance imaging (MRI) has potential advantages in evaluating CSP. This study aimed to analyze the value of MRI with different combinations of sequences in diagnosing CSP following a cesarean section and to evaluate the clinical value of MRI in classifying CSP.

Methods: We conducted a retrospective analysis on the clinical and imaging data of 80 patients with suspected CSP on ultrasound examination. The MRI data of all patients were divided into four combinations: combination A, T1-weighted imaging (T1WI) + T2-weighted imaging (T2WI); combination B, T1WI + T2WI + diffusion-weighted imaging (DWI); combination C, T1WI + T2WI + dynamic contrast-enhanced (DCE) MRI; and combination D, T2WI + DWI + DCE-MRI. The differences between these MRI sequence combinations were compared. Imaging features were observed, recorded, and used for MRI classification. Differences in imaging features between MRI classifications were also compared to determine their clinical significance.

Results: Of the 80 cases confirmed by postoperative pathology, 67 (83.75%) were CSP. The area under the curve for the combinations C and D was larger (0.966 and 0.979, respectively) than that for combination A (0.883). The sensitivity, specificity, positive predictive value, and negative predictive value for combinations C and D were higher (combination C: sensitivity 98.51%, specificity 92.31%, positive predictive value 98.53%, and negative predictive value 92.31%; combination D: sensitivity 95.52%, specificity 92.31%, positive predictive value 98.46%, and negative predictive value 80.00%). The distribution of CSP type I (filled type), type II (partially filled type), and type III (covered type) was 19.40%, 59.70%, and 20.90%, respectively. There was no statistically significant difference in the length of the contact surface between the gestational sac and the scar among the MRI-type groups (H =0.012; P=0.994). However, the minimum thickness of the scar at the implantation site of type I was less than that in type II (H =-16.192; P=0.028), and the area of the gestational sac in the sagittal position was smaller in type I than in type III (H =-24.467; P=0.003).

Conclusions: The preferred MRI sequence combination for diagnosing CSP should be T2WI + DWI + DCE-MRI. MRI can effectively visualize the relationship between the gestational sac and the incisional diverticulum in CSP and facilitate imaging-based staging.

Keywords: Scar pregnancy; magnetic resonance imaging (MRI); sequence combinations.

Figure 1

Flowchart of patient inclusion. Combination A: T1WI + T2WI. Combination B: T1WI + T2WI + DWI. Combination C: T1WI + T2WI + DCE-MRI. Combination D: T2WI + DWI + DCE-MRI. CSP, cesarean scar pregnancy; DCE, dynamic contrast-enhanced; DWI, diffusion-weighted imaging; MRI, magnetic resonance imaging; T1WI, T1-weighted imaging; T2WI, T2-weighted imaging; type I, filled type; type II, partially filled type; type III, covered type.

Figure 2

ROC curves for the comparison of diagnostic efficacy of the different MRI sequence combinations. Combination A: T1WI + T2WI. Combination B: T1WI + T2WI + DWI. Combination C: T1WI + T2WI + DCE-MRI. Combination D: T2WI + DWI + DCE-MRI. DCE, dynamic contrast-enhanced; DWI, diffusion-weighted imaging; MRI, magnetic resonance imaging; ROC, receiver operating characteristic; T1WI, T1-weighted imaging; T2WI, T2-weighted imaging.

Figure 3

A 36-year-old female with type I CSP. The scores for Combinations A, B, C, and D were 3, 4, 5, and 5 points, respectively. The patient only underwent curettage surgery. (A) The T1WI transverse axial position showed that the myometrium of the anterior and lower wall of the uterus was thin; a cystic long T1 signal shadow (red arrow) was visible, and the cyst wall was isointense. (B) DWI showed that the cyst wall (red arrow) had a slightly high signal. (C) The T2WI sagittal position showed that the cyst wall had a slightly high signal, the gestational sac was clearly demarcated from the uterine wall, the incision diverticulum was clear, and the gestational sac (red arrow) was completely embedded in it. (D,E) On enhanced scanning, the cyst wall (red arrows) was significantly enhanced, while the cyst cavity was not significantly enhanced. Combination A: T1WI + T2WI. Combination B: T1WI + T2WI + DWI. Combination C: T1WI + T2WI + DCE-MRI. Combination D: T2WI + DWI + DCE-MRI. CSP, cesarean scar pregnancy; DCE, dynamic contrast-enhanced; DWI, diffusion-weighted imaging; MRI, magnetic resonance imaging; T1WI, T1-weighted imaging; T2WI, T2-weighted imaging; type I, filled type.

Figure 4

A 26-year-old female with type II CSP. The patient only underwent curettage surgery. (A) The T1WI sagittal view showed scar shadow (red arrow) in the anterior lower segment of the uterus. (B) The T2WI sagittal view showed a clear scar incision of the diverticulum and partial filling of the gestational sac, with the diverticulum (red arrow) being partially visible. (C) In enhanced imaging in the sagittal view, the gestational sac wall (red arrow) was significantly enhanced, while the inner wall was smooth. CSP, cesarean scar pregnancy; T1WI, T1-weighted imaging; T2WI, T2-weighted imaging; type II, partially filled type.

Figure 5

A 37-year-old female with type III CSP (mass type). The patient underwent curettage and adhesiolysis of the uterine cavity. (A) The T2WI of the sagittal plane showed a mass shadow (red arrow) with mixed high and low signals in the anterior lower segment of the uterus, with no clear cystic diverticulum shadow. (B) Enhanced imaging of the sagittal plane showed obvious strip-like and nodular enhancement in the mass (red arrow), with an unclear boundary with the uterine wall and uneven enhancement of the adjacent uterine wall. CSP, cesarean scar pregnancy; T2WI, T2-weighted imaging; type III, covered type.