The Value Of MRI In The Diagnosis And Differential Diagnosis Of Upper-lateral Intracavitary Pregnancies During The First Trimester

Part Ⅰ Using MRI to differentiate upper-lateral intracavitary pregnancy and interstitial pregnancy for the patients with pregnancies in the uterotubal junction during the first trimesterObjective:To retrospectively evaluate the diagnostic value of MRI for the upper-lateral intracavitary pregnancy(ULIP)and interstitial pregnancy during the first trimester.Methods:This retrospective study involved 59 patients(January 2016 to July 2021)with a preoperative imaging diagnosis of uterotubal junctional pregnancy.Using operative and pathological reports as the reference standard,we identified 22 patients with ULIP and 37 patients with interstitial pregnancy.Two senior radiologists,blinded to the patients’ information,reviewed the MRI images and determined each MRI feature based on the original interpretation criteria.Any disagreement was resolved by discussion to achieve a consensus.The sensitivity and specificity of each MRI feature were calculated according to the reference standard.Data were analyzed using SPSS 20.0 software.A P value less than 0.05 was considered statistically significant.Results:The endometrial thickness in the ULIP group was larger than in the interstitial group(P=0.001).The β-hCG concentration differed significantly between the ULIP group and the interstitial pregnancy group(P=0.001).The cutoff value of the endometrial thickness was 11.5 mm with a sensitivity,specificity,and area under the curve that were 77.3%,64.9%,and 0.743,respectively.Two key features to diagnose ULIP were"medial free edge" and "medial free edge plus above-cutoff endometrial thickness".The sensitivity and specificity of the medial free edge were 100%and 94.9%,respectively.The sensitivity and specificity of the medial free edge plus above-cutoff endometrial thickness were 77.3%and 100%,respectively.The key feature to diagnose interstitial pregnancy was an "intact lateral junctional zone",of which the sensitivity and specificity were 94.6%and 100%,respectively.Conclusion:MRI can be used to differentiate the upper-lateral intracavitary pregnancy and interstitial pregnancy during the first trimester.Three key MRI features are identified to differentiate the ULIP and interstitial pregnancies,including "medial free edge","medial free edge plus above-cutoff endometrial thickness",and "intact lateral junctional zone".With the determination of the sensitivity and specificity of the three MRI features,our study provides important information for optimizing the management strategies of these two obstetric conditions.Part Ⅱ Two subtypes of upper-lateral intracavitary pregnancy identified by MRI during the first trimesterObjective:The purpose of this study is to explore the possible clinical classification of upper-lateral intracavitary pregnancy through preoperative MRI features and related clinical manifestations.Methods:This retrospective study involved 28 women with surgically and pathologically confirmed ULIP from January 2016 to July 2022.Based on the cutoff value(11.5mm)of endometrial thickness(EMT),the patients were divided into above-cutoff EMT(n=22)and below-cutoff EMT(n=6)groups.Two board-certified radiologists,blinded to the patients’ information,independently reviewed the MRI images,and determined each MRI feature,including EMT and perigestational sac endometrial interruption.Disagreements were resolved by discussion to achieve a consensus.Data were analyzed using SPSS 26.0 software.A P value less than 0.05 was considered statistically significant.Results:Two subtypes of surgery-categorized ULIP were identified.Type-I ULIP(n=22,EMT≥11.5mm),when compared to the type-Ⅱ ULIP,(n=6,EMT<11.5mm),demonstrated lower incidence of peri-GS endometrial interruption(2/22[9.1%]vs 6/6[100%];P=0.001),higher logarithmic β-human chorionic gonadotropin β-hCG)concentration(4.7±0.4 mIU/ml vs 4.2±0.6 mIU/ml;P=0.026),lower rate of repeated dilatation and curettage(1/22[4.6%]vs 4/6[66.7%];P=0.003),less intraoperative blood loss(10.1±6.3 ml vs 28.3±18.3 ml;P=0.001),and shorter hospital stay(2.8±1.7 days vs 7.5±3.8 days;P=0.001).The periGS endometrial interruption negatively correlated with EMT(OR=0.55;P=0.001)and logarithmic β-hCG concentration(OR=0.08;P=0.045).The below-cutoff EMT negatively correlated with β-hCG concentration(OR=0.06;P=0.021).Conclusion:Based on the cutoff value(11.5 mm)of EMT,the ULIP women can be divided into two groups,the above-cutoff EMT group(type-Ⅰ ULIP)and the below-cutoff EMT group(type-Ⅱ ULIP).Each type has unique MRI features and related clinical manifestations.The main contribution of this study is to identify the type-Ⅱ ULIP,a previously undocumented intracavitary pregnancy type with thinner EMT,interrupted peri-gestational sac endometrium,and higher perioperative complexity.Our findings provide valuable information to optimize the current management strategies.