MRI Assessed Placental Location as a Diagnostic Tool of Placental Invasiveness and Maternal Peripartum Morbidity.

Placenta accreta spectrum (PAS) disorder is one of the leading causes of peripartum maternal morbidity and mortality; its early identification during pregnancy is of utmost importance to ensure the optimal clinical outcome. The aim of the present study is to investigate the possible association of the presence and type/location of placenta previa on MRI with PAS and maternal peripartum outcome. One hundred eighty-nine pregnant women (mean age: 35 years; mean gestational age: 32 weeks) at high risk for PAS underwent a dedicated placental MRI. All women underwent a C-section within 6 weeks from the MRI. All MRIs were evaluated by two experienced genitourinary radiologists for presence, type (complete/partial vs. marginal/low lying), and location (anterior vs. anterior-posterior vs. posterior) of placenta previa. Statistical analysis was performed for possible association of type/location of previa with placental invasiveness and peripartum outcomes. Intraoperative information was used as a reference standard. Complete/partial previa was detected in 143/189 (75.6%) and marginal/low lying previa in 33/189 (17.5%) women; in 88/189 (46.6%) women, the placenta had anterior-posterior, in 54/189 (28.6%) anterior and in 41/189 (21.7%) posterior. Complete/partial previa had an at least 3-fold probability of invasiveness and was more frequently associated with unfavorable peripartum events, including massive intraoperative blood loss or hysterectomy, compared to low-lying/marginal placenta. Posterior placental location was significantly associated with lower rates of PAS and better clinical outcomes. In conclusion, the type and location of placenta previa shown with MRI seems to be associated with severity of complications during delivery and should be carefully studied.

Manifestations of Ovarian Cancer in Relation to Other Pelvic Diseases by MRI.

Imaging plays a pivotal role in the diagnostic approach of women with suspected ovarian cancer. MRI is widely used for preoperative characterization and risk stratification of adnexal masses. While epithelial ovarian cancer (EOC) has typical findings on MRI; there are several benign and malignant pelvic conditions that may mimic its appearance on imaging. Knowledge of the origin and imaging characteristics of a pelvic mass will help radiologists diagnose ovarian cancer promptly and accurately. Finally, in special subgroups, including adolescents and gravid population, the prevalence of various ovarian tumors differs from that of the general population and there are conditions which uniquely manifest during these periods of life.

A Novel Approach for Estimating Ovarian Cancer Tissue Heterogeneity through the Application of Image Processing Techniques and Artificial Intelligence.

PURPOSE: Tumor heterogeneity may be responsible for poor response to treatment and adverse prognosis in women with HGOEC. The purpose of this study is to propose an automated classification system that allows medical experts to automatically identify intratumoral areas of different cellularity indicative of tumor heterogeneity. METHODS: Twenty-two patients underwent dedicated pelvic MRI, and a database of 11,095 images was created. After image processing techniques were applied to align and assess the cancerous regions, two specific imaging series were used to extract quantitative features (radiomics). These features were employed to create, through artificial intelligence, an estimator of the highly cellular intratumoral area as defined by arbitrarily selected apparent diffusion coefficient (ADC) cut-off values (ADC < 0.85 × 10-3 mm2/s). RESULTS: The average recorded accuracy of the proposed automated classification system was equal to 0.86. CONCLUSION: The proposed classification system for assessing highly cellular intratumoral areas, based on radiomics, may be used as a tool for assessing tumor heterogeneity.

Comparison between 1.5-T and 3.0-T MRI for the diagnosis of placenta accreta spectrum disorders.

PURPOSE: Accurate antenatal diagnosis of placenta accreta spectrum (PAS) is important for optimal management. The purpose of this study was to compare the respective capabilities of 1.5-T and 3.0-T MRI in the diagnosis of PAS. MATERIALS AND METHODS: Between March 2016-March 2021, 190 pregnant women at high risk for PAS underwent dedicated prenatal MRI with either 1.5-T or 3.0-T units at a tertiary imaging center. Cesarian section and MRI were performed less than 6 weeks from each other. Prospectively collected data were evaluated by two experienced genitourinary radiologists for presence and extent of PAS. A comparative study was designed to investigate differences in predictive ability between 1.5-T and 3.0-T MRI groups. Sensitivity, specificity, accuracy, negative and positive prognostic values relative to intraoperative/histological findings, were computed for both groups and were compared with chi-square (χ 2) test. Interobserver agreement was estimated using Kappa test. RESULTS: One hundred-eighty-two gravid women were included in the study; of these, 91/182 (50%) women were evaluated with 1.5-T (mean age, 35 ± 5.1 [SD] years; mean gestational age: 32.5 weeks) and 91/182 (50%) with 3.0-T MRI (mean age, 34.9 ± 4.9 [SD] years; mean gestational age, 32.1 weeks). 1.5-T MRI yielded 95.7% sensitivity (95% CI: 87.8-99.1) and 81.8% specificity (95% CI: 59.8) and 3.0-T MRI 93.8% sensitivity (95% CI: 86.0-97.9) and 83.3% specificity (95% CI: 48.2-97.7) for PAS identification, with no differences between the two groups (P = 0.725 and P >0.999, respectively). MRI showed excellent predictive ability for detecting extrauterine placental spread with 100% sensitivity (95% CI: 89.4-100.0), 96.7% specificity (95% CI: 88.1-99.6) for 1.5-T and 97% sensitivity (95% CI: 84.2-99.9), 96.7% specificity (95% CI: 88.1-99.6) for 3.0-T without differences between the two groups (P > 0.999). Interobserver agreement was excellent for both groups. The most frequently detected MRI signs of PAS for both 1.5-T and 3.0-T groups were placental heterogeneity (n = 85, 93.5% vs. n = 90, 98.9%; P = 0.413), and intraplacental fetal vessels (n = 64, 70.3% vs. n = 65, 71.4%; P = 0.870). CONCLUSION: This study suggests that 3.0-T MRI and 1.5-T MRI are equivalent for the diagnosis of PAS.

Comparison of MRI Features of Fat Fraction and ADC for Early Treatment Response Assessment in Participants with Multiple Myeloma.

Background An imaging-based predictor of response could provide prognostic information early during treatment course in patients with multiple myeloma (MM). Purpose To investigate if very early changes in bone marrow relative fat fraction (rFF) and apparent diffusion coefficient (ADC) histogram metrics, occurring after one cycle of induction therapy in participants with newly diagnosed MM, could help predict overall best response status. Materials and Methods This prospective study included participants with MM who were enrolled between August 2014 and December 2017. Histogram metrics were extracted from ADC and rFF maps from MRI examinations performed before treatment and after the first treatment cycle. Participants were categorized into the very good partial response (VGPR) or better group and the less than VGPR group per the International Myeloma Working Group response criteria. ADC and rFF map metrics for predicting treatment response were compared using the Wilcoxon rank test, and the false discovery rate (FDR) was used to correct for multiple comparisons. Results A total of 23 participants (mean age, 65 years ± 11 [SD]; 13 men) were evaluated. There was no evidence of a difference in ADC metrics between the two responder groups after correcting for multiple comparisons. The rFF histogram changes between pretreatment MRI and MRI after the first treatment cycle (ΔrFF) that provided significant differences between the VGPR or better and less than VGPR groups were as follows: ΔrFF_10th Percentile (median, 0.5 [95% CI: 0, 1] vs -2.5 [95% CI: -5.1, 0.1], respectively), ΔrFF_90th Percentile (median, 2 [95% CI: 1, 6.8] vs -0.5 [95% CI: -1, 0]), ΔrFF_Mean (median, 3.4 [95% CI: 0.3, 7.6] vs -1.1 [95% CI: -1.8, -0.7]), and ΔrFF_Root Mean Squared (median, 3.2 [95% CI: 0.3, 6.1] vs -0.7 [95% CI: -1.3, -0.4]) (FDR-adjusted P = .03 for all), and the latter two also presented mean group increases in the VGPR or better group that were above the upper 95% CI limit for repeatability. Conclusion Very early changes in bone marrow relative fat fraction histogram metrics, calculated from MRI examination at baseline and after only one cycle of induction therapy, may help to predict very good partial response or better in participants with newly diagnosed multiple myeloma. © RSNA, 2022 Online supplemental material is available for this article.

Imaging during pregnancy: What the radiologist needs to know.

During the last decades, there has been a growing demand for medical imaging in gravid women. Imaging of the pregnant woman is challenging as it involves both the mother and the fetus and, consequently, several medical, ethical, or legal considerations are likely to be raised. Theoretically, all currently available imaging modalities may be used for the evaluation of the pregnant woman; however, in practice, confusion regarding the safety of the fetus often results in unnecessary avoidance of useful diagnostic tests, especially those involving ionizing radiation. This review article is focused on the current safety guidelines and considerations regarding the use of different imaging modalities in the pregnant population; also presented is an imaging work-up for the most common medical conditions of pregnant women, with emphasis on fetal and maternal safety.

Intraplacental Fetal Vessel Diameter May Help Predict for Placental Invasiveness in Pregnant Women at High Risk for Placenta Accreta Spectrum Disorders.

Background Prenatal identification of placenta accreta spectrum (PAS) disorder is essential for treatment planning. More objective means for predicting PAS and clinical outcome may be provided by MRI descriptors. Purpose To investigate the association of intraplacental fetal vessel (IFV) diameter at MRI with PAS and peripartum complications. Materials and Methods Between March 2016 and October 2019, 160 gravid women suspected of having PAS underwent placental MRI as part of a prospective trial. Secondary analysis was performed by two experienced genitourinary radiologists for presence and maximum diameter of IFVs. Relative risk ratios were computed to test the association of IFVs with presence and depth of PAS invasiveness. Receiver operating characteristic analysis was used to evaluate the ability of IFV diameter to help predict PAS, placenta percreta, and peripartum complications and for comparison of the area under the curve (AUC) versus that from other combined MRI predictors of PAS (eg, myometrial thinning, intraplacental T2-hypointense bands, uterine bulge, serosal hypervascularity, and signs of extrauterine placental spread). Intraoperative and histopathologic findings were the reference standard. Results A total of 155 women were evaluated (mean age, 35 years ± 5 [standard deviation]; mean gestational age, 32 weeks ± 3). PAS was diagnosed in 126 of 155 women (81%) (placental percreta in 68 of 126 [54%]). At delivery, 30 of 126 women (24%) experienced massive blood loss (>2000 mL). IFVs were detected at MRI in 109 of 126 women with PAS (86%) and in 67 of 68 women with placental percreta (98%). The relative risk ratio was 2.4 (95% CI: 1.6, 3.4; P < .001) for PAS and 10 (95% CI: 1.5, 70.4; P < .001) for placental percreta when IFVs were visible. IFVs of 2 mm or greater were associated with PAS (AUC, 0.81; 95% CI: 0.67, 0.95; P = .04). IVFs of 3 mm or greater were associated with placenta percreta (AUC, 0.81; 95% CI: 0.73, 0.89; P < .001) and with peripartum complications, including massive bleeding (AUC, 0.80; 95% CI: 0.71, 0.89; P < .001). Combining assessment of IFVs with other MRI descriptors improved the ability of MRI to predict PAS (AUC, 0.94 vs 0.89; P = .009). Conclusion Assessment of intraplacental fetal vessels with other MRI descriptors improved the ability of MRI to help predict PAS. Vessel diameter of 3 mm or greater was predictive of placenta percreta and peripartum complications. © RSNA, 2020 Online supplemental material is available for this article. See also the editorial by Dighe in this issue.

The Role of Low Dose Whole Body CT in the Detection of Progression of Patients with Smoldering Multiple Myeloma.

Multiple myeloma (MM) is the second most common hematological malignancy, characterized by plasma cell bone marrow infiltration and end-organ involvement. Smoldering MM (SMM) is an intermediate clinical entity between MGUS and MM, with a risk of progression to symptomatic disease 10% per year. Bone disease is the most frequent symptom of MM, with ~90% of patients developing bone lesions throughout their disease course. Therefore, imaging plays a crucial role in diagnosis and management. Whole-body low-dose CT (WBLDCT) is widely available and has been incorporated in the latest diagnostic criteria of the IMWG. The purpose of this study was to evaluate the role of WBLDCT in the early identification of lesions in patients with SMM who progress solely with bone disease. In total, 100 asymptomatic patients were consecutively assessed with WBLDCT from July 2013 until March 2020 at baseline, 1-year after diagnosis and every 1 year thereafter. Ten percent of patients were identified as progressors with this single imaging modality. This is the first study to evaluate prospectively patients with SMM at different time points to identify early bone lesions related to MM evolution. Serial WBLDCT studies can identify early myeloma evolution and optimize disease monitoring and therapeutic strategies.

Imaging of Gynecologic Malignancy in a Reproductive Age Female: Cancer During Pregnancy.

Gynecologic malignancies are common among cancers diagnosed during pregnancy, especially those of cervical and ovarian origin. Imaging is an important part of the diagnosis, staging, and follow-up of pregnancy-associated gynecologic tumors, with sonography and magnetic resonance (MR) imaging being the most suitable modalities. MR imaging is particularly useful in cervical cancer for the evaluation of tumor size, nodal, and extrapelvic disease. Ovarian tumor is initially diagnosed with sonography; MR imaging should be performed in cases of indeterminate ultrasonography findings and for staging. Pregnancy-related changes may be responsible for erroneous diagnosis; radiologists should be aware of such pitfalls to avoid misinterpretation.

Society of Abdominal Radiology (SAR) and European Society of Urogenital Radiology (ESUR) joint consensus statement for MR imaging of placenta accreta spectrum disorders.

OBJECTIVES: This study was conducted in order to establish the joint Society of Abdominal Radiology (SAR) and European Society of Urogenital Radiology (ESUR) guidelines on placenta accreta spectrum (PAS) disorders and propose strategies to standardize image acquisition, interpretation, and reporting for this condition with MRI. METHODS: The published evidence-based data and the opinion of experts were combined using the RAND-UCLA Appropriateness Method and formed the basis for these consensus guidelines. The responses of the experts to questions regarding the details of patient preparation, MRI protocol, image interpretation, and reporting were collected, analyzed, and classified as "recommended" versus "not recommended" (if at least 80% consensus among experts) or uncertain (if less than 80% consensus among experts). RESULTS: Consensus regarding image acquisition, interpretation, and reporting was determined using the RAND-UCLA Appropriateness Method. The use of a tailored MRI protocol and standardized report was recommended. CONCLUSIONS: A standardized imaging protocol and reporting system ensures recognition of the salient features of PAS disorders. These consensus recommendations should be used as a guide for the evaluation of PAS disorders with MRI. KEY POINTS: • MRI is a powerful adjunct to ultrasound and provides valuable information on the topography and depth of placental invasion. • Consensus statement proposed a common lexicon to allow for uniformity in MRI acquisition, interpretation, and reporting of PAS disorders. • Seven MRI features, namely intraplacental dark T2 bands, uterine/placental bulge, loss of low T2 retroplacental line, myometrial thinning/disruption, bladder wall interruption, focal exophytic placental mass, and abnormal vasculature of the placental bed, reached consensus and are categorized as "recommended" for diagnosing PAS disorders.

Αdnexal cystic lymphangiomas in patients with massive leiomyomatous uterus: a not so uncommon finding on pelvic MRI.

PURPOSE: To investigate any association between the presence of an adnexal cystic lymphangioma (ACL) and an enlarged leiomyomatous uterus. METHODS: A retrospective observational study was conducted by two expert radiologists using a 10-year MRI database (2008-2018); 85 patients (mean age: 45.5 years ± 10.9) were considered eligible due to the presence of a single (n = 31) or multiple (n = 54) leiomyomas causing distortion of the uterine contour and uterine enlargement. The association of specific leiomyoma features (longest diameter (Dmax), location, number) and uterine volume with the presence of ACL was statistically tested. Diagnosis of ACL was based on typical imaging features (n = 14) and intraoperative/histological findings (n = 3). RESULTS: ACL (unilateral = 9, bilateral = 8) was recorded in 17/85 (20%) of patients; it was more frequently observed when the largest leiomyoma was located in the uterine fundus (33.3%). Patients with ACL had significantly more leiomyomas (median: 5 vs. 2, p = 0.043), greater Dmax of largest leiomyoma (median: 13.3 vs. 7.2 cm, p < 0.001), and larger uterine volumes (median: 676.7 vs. 223.1 cm3, p < 0.001) compared to patients without ACL. ROC curve analysis for a number of leiomyomas showed that the optimal cut-off for the prediction of ACL was the presence of 5 leiomyomas with 53.8% sensitivity and 84% specificity (AUC = 0.65, 95% CI 0.51-0.83, p = 0.049), Dmax of largest leiomyoma 9.1 cm with 76.5% sensitivity and 77.9% specificity (AUC = 0.83, 95% CI 0.73-0.94, p < 0.001), and uterine volume 311 cm3 with 71% sensitivity and 75% specificity (AUC = 0.79, 95% CI 0.66-0.92, p < 0.001). CONCLUSIONS: The presence of ACL is significantly associated with number of leiomyomas, Dmax of largest leiomyoma, and uterine volume; prospective evaluation of our results is needed to investigate its clinical significance.

Treatment of Bing-Neel syndrome with first line sequential chemoimmunotherapy: A case report.

RATIONALE: Bing-Neel syndrome (BNS) is a rare manifestation of Waldenström macroglobulinemia (WM) with <200 cases reported in the literature. Herein, we describe a case of newly diagnosed BNS treated with a novel therapeutic strategy. PATIENT CONCERNS: A 67-year-old woman diagnosed with asymptomatic WM 3 years ago presented with gradual vision deterioration the past 3 months. Ophthalmologic examination revealed bilateral reduction in visual acuity (7/10) and bilateral optic disc swelling which was more prominent in the left eye. DIAGNOSES: Brain imaging revealed bilateral swelling of optic nerves extending from the retina to the optic chiasm and swelling of the left optic tract. Patchy enhancement of optic nerves was also shown upon intravenous contrast administration. Flow cytometry of the cerebrospinal fluid (CSF) revealed the presence of κ-light chain restricted, monoclonal B-lymphocytes. CSF protein electrophoresis showed a monoclonal band in the gamma region and immunofixation was positive for immunoglobulin M and kappa light chain. Thus, the diagnosis of BNS was established. INTERVENTIONS: The patient was initially treated with intrathecal methotrexate and systemic chemotherapy. Following 2 intrathecal methotrexate infusions, CSF flow cytometry did not detect any cells, whereas the patient reported improvement in visual acuity. Therefore, we opted to start maintenance treatment with IV rituximab and per os ibrutinib. OUTCOMES: Following 1 year posttreatment initiation, visual problems have resolved completely and the patient remains on hematologic and imaging complete response. LESSONS: We propose a novel sequential chemoimmunotherapy approach for BNS treatment aiming both at rapid disease control and deep and durable remission with minimization of induced toxicity.

Stripped fetal vessel sign: a novel pathological feature of abnormal fetal vasculature in placenta accreta spectrum disorders with MRI correlates.

Abnormal intraplacental hypervascularity is a well-known MRI feature of Placenta Accreta Spectrum (PAS), but the precise nature of these vessels has not yet been specified. Histopathological examination of eleven PAS-hysterectomy specimens and subsequent review of the corresponding MRIs, revealed the presence of large fetal vascular trunks extending deep towards the placental periphery and demonstrating deficient branching along their course ('stripped-fetal-vessel' sign). To our knowledge, this is the first report to describe the pattern of abnormal fetal vasculature in correlation with MRI in PAS.

MRI prognosticators for adverse maternal and neonatal clinical outcome in patients at high risk for placenta accreta spectrum (PAS) disorders.

BACKGROUND: Placenta accreta spectrum (PAS) disorders may be associated with significant mortality and morbidity for both mother and fetus. PURPOSE/HYPOTHESIS: To identify MRI risk factors for poor peripartum outcome in gravid patients at risk for PAS. STUDY TYPE: Prospective. POPULATION: One hundred gravid women (mean age: 34.9 years) at third trimester, with placenta previa. FIELD STRENGTH/SEQUENCE: T2 -SSTSE (single-shot turbo spin echo), T2 -TSE, T1 -TSEFS (TSE images with fat-suppression) at 1.5T. ASSESSMENT: Fifteen MRI features considered indicative of PAS were recorded by three radiologists and were tested for any association with the following adverse peripartum maternal and neonatal events: increased operation time, profound blood loss, hysterectomy, bladder repair, ICU admission, prematurity, low birthweight, and 5-minute APGAR score <7. STATISTICAL TESTS: Kappa (K) coefficients were computed as a measure of agreement between intraoperative information/histology and MRI results as well as for interobserver agreement; chi-square and Fisher's exact tests were used to explore the association of the MRI signs with clinical complications. A score was calculated by adding all recorded MRI signs and its predictive ability was tested using receiver operating characteristic (ROC) analysis, against all complications, separately; odds ratios (ORs) for optimal cutoffs were determined with logistic regression analysis. RESULTS: There was excellent agreement (K >0.75, P < 0.001) between MRI and intraoperative findings for invasive placenta, bladder and parametrial involvement. Intraplacental T2 dark bands, myometrial disruption, uterine bulge, and hypervascularity at the utero-placental interface or parametrium, showed significant association (P < 0.005) with poor clinical outcome for both mother and fetus. The MRI score showed significant predictive ability for each adverse maternal event (area under the curve [AUC]: 0.85-0.97, P < 0.001). The presence of ≥3 MRI signs was the cutoff point for a complicated delivery (OR: 19.08, 95% confidence interval [CI]: 6.05-60.13) and ≥6 MRI signs was the cutoff point for massive bleeding (OR: 90.93, 95% CI: 11.3-729.23), hysterectomy (OR: 72.5, 95% CI: 17.9-293.7), or extensive bladder repair (OR: 58.74, 95% CI: 7.35-469.32). The MRI score was not significant for predicting adverse neonatal events including preterm delivery (P = 0.558), low birthweight (P = 0.097), and 5-minute Apgar score (P = 0.078). DATA CONCLUSION: Preoperative identification of specific MRI features may predict peripartum course in high-risk patients for PAS. LEVEL OF EVIDENCE: 1 Technical Efficacy: Stage 5 J. Magn. Reson. Imaging 2019;50:602-618.

Abdominal Radical Trachelectomy for Early-Stage Cervical Cancer During Pregnancy: A Provocative Surgical Approach. Overview of the Literature and a Single-Institute Experience.

OBJECTIVE: Treatment of pregnancy complication due to malignancy of the cervix constitutes a great clinical challenge between optimal maternal therapy and fetal viability. Radical trachelectomy in early-stage cervical cancer during pregnancy instead of radical hysterectomy presents an alternative approach that can offer a satisfactory outcome for the mother and fetus. MATERIALS AND METHODS-RESULTS: A literature search of articles in English has been performed. Until now, 28 women with cervical cancer, including 2 who were managed and treated in our institute, who underwent a radical trachelectomy during pregnancy have been reported. We overviewed a total of 13 abdominal trachelectomies, 13 vaginal trachelectomies, and 2 laparoscopic trachelectomies. CONCLUSIONS: Radical trachelectomy can widen the therapeutic approach of early-stage cervical cancer in pregnant women who wish to preserve their pregnancy, providing a possibility of receiving the proper treatment with no delay.

MR imaging features and tumor biomarkers of screen-detected and non-screen detected breast cancers: preliminary results of a comparative study.

PURPOSE: To investigate differences in clinical features, MRI findings and tumor biomarker characteristics in screen-detected (SCD) and non-screendetected (NSCD) cancers. MATERIAL AND METHODS: A total of 62 women (mean age, 48.4 years; range, 33-68 years) with biopsy confirmed breast cancer who underwent preoperative breast MRI were retrospectively evaluated by two expert radiologists. The women were divided into two groups according to the mode of cancer detection (Group A: screen- detected, Group B: non-screen/symptomatic cancer) and clinical, histopathological, MRI characteristics and biomarker features in each group were evaluated. RESULTS: NSCD tumors had significantly greater size (3.5 cm vs. 2.1 cm) and Ki-67 expression (68.4% vs. 41.7%) in comparison to SCD cancers. NSCD cancers were less likely to have strongly positive progesterone receptors (Pr) and more likely to have Ki-67 > 15% or positive nodal status (47.4% vs. 8.3%). Increased breast density (ACR C and D: 78.9% vs. 50%ACR A and B) and intense background parenchymal enhancement (BPE, moderate/marked: 42.1% vs. 8.3% minimal/mild) were significantly more frequent in NSCD cases. CONCLUSION: NSCD cancers had higher prevalence of poor prognostic characteristics in comparison to SCD tumors, including larger tumor size, higher Ki-67 index, and positive nodes. Increased fibroglandular tissue and intense BPE were both strongly associated with NSCD cancers, supporting their use as potential MR biomarkers in breast cancer risk models.

MRI Features Predictive of Invasive Placenta With Extrauterine Spread in High-Risk Gravid Patients: A Prospective Evaluation.

OBJECTIVE: The objective of our study was to evaluate MRI diagnostic ability in predicting invasive placenta with extrauterine spread in high-risk gravid patients. SUBJECTS AND METHODS: Between March 2016 and June 2017, 49 patients (mean age, 35.7 years; mean gestational age, 32.5 weeks) with sonographically confirmed placenta previa underwent dedicated MRI. All MRI examinations were reviewed by two experienced radiologists prospectively. Intraoperative and pathologic findings were the standard of reference. Kappa values were calculated to assess the agreement between MRI findings and histologic results as well as interrater reliability. ROC curve analysis was used to test the discriminative ability of MRI features for invasive placenta with extrauterine spread. Stepwise multiple logistic regression analysis was performed to identify any MRI findings predictive of invasive placenta and of bladder and parametrial involvement. RESULTS: MRI exhibited significant overall accuracy (AUC = 0.77, p = 0.006) in identifying invasive placenta with 100% sensitivity and negative predictive values; it was highly specific (100%) in identifying placental extension to both bladder and parametrial tissues. Lumpy tapering of the placental edges, intraplacental dark T2 bands, prominent intraplacental vascularity, and serosal hypervascularity were independently associated with an increased risk for invasive placenta. Serosal hypervascularity and vesicouterine space hypervascularity were independent predictors of bladder invasion; abnormal vascularization within the parametrial fat was significant for parametrial invasion. CONCLUSION: MRI is highly accurate in depicting placental extrauterine spread. The presence of abnormal vessels at the uterine serosa was the most important MRI feature for identifying invasive placenta. An abnormal vascular network within the vesicouterine space or parametrium was the most reliable MRI sign for detecting bladder or parametrial involvement.