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As fetal gestational age increases, other modalities such as ultrasound have demonstrated increased levels of heterogeneity in the normal placenta. In this study, we introduce and apply ROI-based texture analysis to a retrospective fetal MRI database to characterize the second-order statistics of placenta and to evaluate the relationship between heterogeneity and gestational age. Positive correlations were observed for several Haralick texture metrics derived from fetal-brain specific T2-weighted and gravid uterus T1-weighted and T2-weighted images, confirming a quantitative increase in placental heterogeneity with gestational age. Our study shows the importance of identifying baseline MR textural changes at certain gestational ages from which placental diseased states may be compared. Specifically, when evaluating for placental invasion or insufficiency, findings should be evaluated in the context of the normal placental aging process, which occurs throughout gestation.

Purpose To evaluate bSSFP (balanced steady state free precession) and half-Fourier RARE (rapid acceleration with relaxation enhancement) MRI sequences in their ability to demonstrate fetal anatomic landmarks, quantify the degree of cerebellar herniation in Chiari II malformations and level and length of the associated open neural tube defects, as well as evaluate interobserver reliability of these measurements. Materials and Methods Two independent observers retrospectively reviewed MRIs of 37 fetuses with Chiari II malformations and associated open neural tube defects (mean gestational age: 27 weeks 2 days). Comparison of bSSFP and RARE included: (i) Ability to confidently identify anatomic landmarks of the posterior fossa and spine; (ii) Measurements of the foramen magnum, cerebellar tonsillar herniation length, intervertebral disc space level of tonsillar herniation, open neural tube defect length, and disc space start and end level of the open neural tube defect; (iii) Observed conspicuity of anatomic landmarks. Results There was no significant difference in assessment of cerebellar tonsillar herniation or open neural tube defect level between bSSFP and RARE for either observer. Intervertebral discs were more conspicuous on bSSFP while cerebellar tonsils were more conspicuous on RARE (P < 0.05). Interobserver reliability was strong for both sequences in assessing the foramen magnum (r = 0.95, 0.94), tonsillar herniation length (r = 0.93, 0.95), and open neural tube defect length (r = 0.97, 0.96). Conclusion Despite improved conspicuity of the intervertebral discs with bSSFP and cerebellar tonsils with RARE, there is no significant difference in measurement of hindbrain herniation or open neural tube defect level; interobserver reliability is excellent for both sequences. J. Magn. Reson. Imaging 2013;38:786–793. © 2013 Wiley Periodicals, Inc.

Introduction Current medical education promotes enhanced integration of various disciplines and early exposure to clinically relevant topics. Against this background, we have developed a team-based learning (TBL) module for medical students in the preclerkship period that integrates embryology, anatomy, and radiology of the head and neck region. Methods The module, which includes prereading assignments, readiness assurance tests, and an application exercise, focuses on the development of the head and neck region. Students were asked to consolidate their knowledge of the topic—acquired as part of their regular curriculum—and to apply this knowledge to cases of cervical cysts and cleft lip/palate. Results The TBL module was developed for a class of 234 students. The students performed well in the TBL module. Although many students perceived the session as time-consuming, the majority of students evaluated it as relevant for their understanding of the course material and a valuable adjunct to their course. Discussion To our knowledge, as of this writing, no TBL modules have been published that focus on the integration of complex embryological topics with anatomy and radiology and that are suitable for medical students at the beginning of their education. Therefore, the presented TBL module fills a gap in material available to educators in the field.

Fetal magnetic resonance (MR) imaging plays an increasing and valuable role in antenatal diagnosis and perinatal management of fetal gastrointestinal (GI) abnormalities. Advances in MR imaging data acquisition and use of motion-insensitive techniques have established MR imaging as an important adjunct to obstetric ultrasonography (US) for fetal diagnosis. In this regard, MR imaging provides high diagnostic accuracy for antenatal diagnosis of common and uncommon GI pathologic conditions. In the setting of fetal GI disease, T1-weighted images demonstrate the amount and distribution of meconium, which is crucial to the diagnostic capability of fetal MR imaging. Specifically, knowledge of the T1 signal intensity characteristics of fetal meconium, the normal pattern of meconium with advancing gestational age, and the expected caliber of small and large bowel in the fetus is key to diagnosis of abnormalities of the GI tract. Use of ultrafast T2-weighted sequences for evaluation of the expected location and morphology of fluid-containing structures, including the stomach and small bowel, in the fetal abdomen further aids in diagnostic confidence. Uncommonly encountered fetal GI pathologic conditions, especially cloacal dysmorphology, may demonstrate characteristic MR imaging patterns, which may add additional information to that from fetal US, allowing improved fetal and neonatal management. This article discusses common indications for fetal MR imaging of the GI tract, imaging protocols for fetal GI MR imaging, the normal appearance of the fetal GI tract with advancing gestational age, and the imaging appearances of common fetal GI abnormalities, as well as uncommon fetal GI conditions with characteristic appearances. (©)RSNA, 2016.

To provide normal biometry of the cerebellar vermis using fetal MR and determine threshold values associated with abnormal neurologic outcome.Cerebellar vermis biometry was applied in prospective, cross-sectional evaluation of fetal brains. Vermis length and inferior vermian distance were obtained in mid-sagittal planes using T2-weighted, single-shot sequences with 1.5 Tesla MR. Measurements were compared with reference nomograms from a retrospective review of fetal brains with normal intracranial anatomy. Observed and predicted measurements of the cerebellar vermis were recorded. Neurologic outcome was classified as normal or abnormal. Unpaired t-tests and discriminate analysis were applied to the two measurements and differences between the observed and predicted values.The reference group included 64 fetuses of 13 to 38 weeks gestation. Both vermis length and inferior vermian distance increased linearly with time (r = 0.92, P 0.001; r = 0.32, P = 0.01). The prospective group included 64 additional fetuses with documented normal (39/64, 61%) and abnormal (25/64, 39%) outcomes. Significant differences were seen in vermis length, inferior vermian distance, and correlation with predicted values based on neurologic outcome (P 0.001). Vermis length discrepancy ≥ 4 mm or inferior vermian distance ≥ 4 mm were associated with abnormal neurologic outcome.MR measurements of a short, raised vermis characterized by a vermis length discrepancy ≥ 4 mm or an inferior vermian distance ≥ 4 mm is associated with abnormal neurologic, syndromic, and developmental outcomes. J. Magn. Reson. Imaging 2016;44:1284-1292.

Although ultrasound is the primary means of screening for fetal central nervous system (CNS) malformations, MRI has demonstrated added value in the evaluation of abnormalities not well assessed with sonography and in select circumstances for screening. In many fetal MRI practices, evaluation of the CNS is the most common indication for fetal MRI. MRI has demonstrated particular utility in evaluating the posterior fossa, midline structures, and cortex in the progressively ossifying fetal skull. The most common CNS indications are identified in Table 6.1 [98].

The objectives of this study were to estimate the rates of sonographically detected anal sphincter defects within 72 h of childbirth and to evaluate intra- and interobserver agreement using three-dimensional (3-D) endoanal sonography data. This is a prospective observational study of primiparous women delivered vaginally. Women without clinically identified anal sphincter lacerations underwent endoanal ultrasonography within 72 h of delivery. Intra- and interobserver agreement for diagnosis of sphincter defects using 3-D endoanal sonography data was calculated using kappa statistics. The rate of sphincter defects in 107 women undergoing 3-D endoanal sonography was 12 %. Characteristics of women with sonographically detected sphincter defects, compared to those without, included a significantly increased rate of clinically diagnosed second-degree lacerations (54 vs 20 %, p 0.008). The intra- and interobserver agreement for diagnosis of sphincter defects using 3-D endoanal sonography data was 0.82 [confidence interval (CI) 0.66–0.99] and 0.72 (CI 0.54–0.92), respectively. Anal sphincter defects detected using endoanal sonography are common, occurring in 12 % of primiparous women, and are significantly associated with other less severe perineal lacerations. Overall and combining sonographically detected defects with clinically diagnosed lacerations, we estimate that 17.8 % of primiparous women delivered vaginally sustain anal sphincter injuries. The intraobserver agreement for diagnosis of sphincter defects is very good and the interobserver agreement is good.

When medical therapy fails for menorrhagia in a premenopausal woman, minimally invasive endometrial ablation can be used as a conservative management alternative to hysterectomy. Endometrial ablation alone is not considered effective contraception, and women of reproductive age can become pregnant after ablative therapy. We now present two cases of pregnancy after endometrial ablation and associated imaging where both cases required cesarean hysterectomy due to post-partum hemorrhage. Pregnancy after endometrial ablation incurs increased morbidity and diagnostic dilemmas.

Although suspected corpus callosum abnormality is a common indication for fetal MR imaging, biometric data specific to MR imaging are sparse. We sought to characterize growth in corpus callosum length by EGA with fetal MR imaging. Corpus callosum segments were assessed and overall corpus callosum length was measured and plotted against the EGA for 68 anatomically normal fetal brains ranging in EGA from 18.5 to 37.7 weeks, and linear and polynomial regression models were calculated. The body of the corpus callosum was identified in all fetuses, followed in frequency by the splenium (91.2%), genu (85.3%), and rostrum (32.4%). Measurements of corpus callosum length by MR imaging were in agreement with values established by sonography. A second-degree polynomial function was the best fit for callosal length by EGA. Understanding this normal growth pattern may enhance detection of subtle growth abnormalities.

To estimate the position of the appendix in term pregnancy using magnetic resonance imaging (MRI) technique.Appendiceal distance from the iliac crest and axis rotation were determined in women between 39 and 40 weeks of gestation who were undergoing scheduled repeat cesarean delivery. A single-shot fast spin-echo MRI sequence of the maternal pelvis was performed without gadolinium contrast. A board-certified radiologist interpreted the MRIs and measured the distance from the base of appendix (or cecum) to the iliac crest in centimeters as well as the axis of the appendix using clock position annotation.Seventy-two women had optimal imaging for interpretation. The mean displacement of the appendix above the iliac crest was 45 mm and was significantly higher than previously described in the term pregnant woman (P.001).Despite recent studies supporting the contrary view, the upward displacement of the appendix in term pregnancy is confirmed in this study.II.

Objective. The purpose of this study was to evaluate the effect of maternal habitus on adequate visualization of fetal anatomy during a standard second-trimester ultrasound examination. Methods. This was a retrospective cohort study of singleton pregnancies at 18 to 24 weeks that underwent sonography over a 5-year period. Pregnancies complicated by an indication for targeted sonography were excluded. Standard ultrasound examinations were performed according to American Institute of Ultrasound in Medicine criteria. Ten anatomic components were evaluated for adequacy of visualization: atria of the cerebral ventricles, posterior fossa, midline face, 4-chamber view of the heart, spine, ventral wall, umbilical cord vessels, stomach, kidneys, and bladder. The body mass index (BMI) was based on the patient's weight at the first prenatal visit. Results. Of 10,112 women who underwent a standard ultrasound examination, 2% were underweight; 38% were of normal weight; 34% were overweight; and 26% were obese. Visualization of fetal anatomy decreased significantly with increasing maternal BMI for the complete survey as well as for each individual component with the exception of the fetal bladder (all P < .001 Among those with a normal or underweight BMI, an overweight BMI, and class 1, 2, and 3 obesity, all 10 anatomic components were adequately visualized at the initial examination in 72%, 68%, 57%, 41 %, and 30% of cases, respectively (P < .001 ). Conclusions. Increasing maternal BMI limits visualization of fetal anatomy during a standard ultrasound examination at 18 to 24 weeks. In obese women, the fetal anatomy survey could be completed during the initial examination in only 50% of cases. Counseling may need to be modified to reflect the limitations of sonography in obese women.

OBJECTIVE: To evaluate prospectively whether salineinfusion sonography endometrial sampling will improve diagnosis of benign and malignant endometrial disease compared with blind endometrial biopsy in perimenopausal and postmenopausal women with abnormal uterine bleeding. METHODS: After initial assessments and endometrial biopsies, women aged 40 or older with abnormal uterine bleeding were referred for transvaginal ultrasonography. Patients with abnormal endometrial evaluations were offered sonohysterography and invited to enter the saline-infusion sonography endometrial sampling study. Saline-infusion sonography endometrial sampling was performed at the end of sonohysterography using an endometrial sampling curette at the sight of the endometrial abnormality or at a representative site in the endometrial cavity if the cavity was normal. Histopathologic diagnoses of blind endometrial biopsy and saline-infusion sonography endometrial sampling were compared with final outcomes. Kappa values for the two sampling techniques were calculated for diagnostic accuracy. RESULTS: A total of 88 saline-infusion sonography endometrial samples were obtained; final outcomes were attained in 80 cases. When comparing saline-infusion sonography endometrial sampling with final outcomes, saline-infusion sonography endometrial sampling provided a diagnosis 89% of the time (95% confidence interval [CI] 82–95%) compared with endometrial biopsy at 52% (95% CI 42–62%). Forty-five patients with endometrial biopsies had final outcomes. When comparing endometrial biopsy with final outcomes, endometrial biopsy underestimated the incidence of pathology, especially when focal lesions and malignancy were present. This difference was statistically significant (P

Objective To determine whether endometrial thickness and other parameters are useful predictors of normal intrauterine pregnancy (IUP) in the setting of vaginal bleeding and sonographic diagnosis of pregnancy of unknown location (PUL). Methods We reviewed the clinical and sonographic records of all 591 patients with vaginal bleeding and a sonographic diagnosis of PUL between 1 July 2005 and 30 June 2006. Data on maternal age, gravidity, parity, estimated gestational age by last menstrual period (EGA by LMP), endometrial thickness and serum β-human chorionic gonadotropin (β-hCG) were collected. Complete data were available for 517 patients, 40 (7.7%) of whom ultimately had normal IUPs. A logistic regression model was constructed using a stepwise procedure to identify variables significantly associated with the outcome of normal IUP. The validity of the model was assessed by receiver–operating characteristics (ROC) curve and Hosmer–Lemeshow Chi-square analysis. Results Four variables (maternal age, EGA by LMP, endometrial thickness and serum β-hCG) were significant in the prediction of normal IUP (area under the ROC curve = 0.86). As maternal age, EGA by LMP and β-hCG increased, the likelihood of a normal IUP decreased, while as the endometrial thickness increased, the likelihood of a normal IUP increased. For each millimeter increase in endometrial thickness, the odds increased by 27% that the patient would have a normal IUP. No normal IUP had an endometrial thickness < 8 mm. Conclusion Increased endometrial thickness predicts normal IUP in patients who present with vaginal bleeding and PUL. Copyright © 2008 ISUOG. Published by John Wiley & Sons, Ltd.

The objective of this study is to describe magnetic resonance (MR) signal intensity (SI) changes in the cervix during pregnancy. This is an observational cohort study of women with a history of preterm delivery. MR imaging sequences were performed every 3 to 4 weeks. Using 8 regions of interest, the SIs are quantified and analyzed with respect to gestational age. Twenty-seven MR studies were performed on a cohort of 8 women. The SIs of the external os are significantly greater than those of the internal os ( P = .035). Similarly, the SIs of the outer stroma are greater than those of the inner stroma (P = .002). As gestational age advances, the inner to outer stromal SI ratio increases, primarily because of a decreasing SI in the outer stromal layer (P = .03). The MR SIs of the cervical stromal zones display variability during pregnancy and decrease with advancing gestation.

Objective The purpose of this study was to compare middle cerebral artery (MCA) peak systolic velocity (PSV) values in monochorionic (MC) and dichorionic (DC) twin pregnancies. Methods This was a prospective cohort study in which MCA Doppler evaluation was performed in unselected twin pregnancies at time of routine sonography between 28 and 32 weeks. Pregnancies with known fetal anomalies, twin-twin transfusion syndrome, and red cell alloimmunization or other conditions associated with anemia were excluded. The intertwin MCA PSV difference, defined as the larger minus smaller PSV value within a pair, was compared in MC and DC pregnancies and was correlated with estimated fetal weight and birth weight discordance. Statistical analyses included Spearman correlation, analysis of variance, a t test, and a chi(2) test. Results Doppler indices were analyzed from 48 twin pregnancies, of which 32 (67%) were DC and 16 (33%) were MC. There was no difference in proportion of values above or below the singleton median for either the larger or smaller DC or MC twins (all P > or = .3). The median intertwin MCA PSV difference was 4.9 cm/s in MC pregnancies and 4.5 cm/s in DC pregnancies (P = .6). There was no significant correlation between the MCA PSV difference and either estimated fetal weight discordance or birth weight discordance in either MC or DC pregnancies (all P > or = .3). Conclusions Middle cerebral artery PSV values in uncomplicated twin pregnancies are comparable with published singleton norms, with a median intertwin MCA PSV difference of approximately 5 cm/s. We found no significant correlation between the intertwin MCA PSV difference and discordance in MC or DC twin gestations.

To compare saline infusion sonography (SIS) to tissue obtained from SIS-guided endometrial sampling (SISES) to determine sensitivity and specificity for benign and malignant conditions of the endometrium.Added value of SISES after SIS was evaluated over 5 years. SIS and SISES techniques have been previously described. Women with abnormal uterine bleeding and endometrial findings underwent SIS. Criteria for SISES included atypical polypoid mass, focal irregularity or global endometrial thickening, nondiagnostic SIS, discordance between SIS and endometrial biopsy, or request from the primary team. Final surgical pathology was compared with SIS and SISES.One-hundred twenty-three SIS patients had SISES. SIS alone had a sensitivity of 100%, specificity of 42%, positive predictive value of 16%, and negative predictive value of 100%. A total of 120 patients had final clinical or surgical outcomes. Specificity was greatly improved with addition of SISES (95.5%, p0.001). Combination of SIS with SISES detected all 12 premalignant and malignant endometrial lesions. Three cases had small foci of hyperplasia (n = 2) or atypia (n = 1) in polyps on final surgical pathology, which were not prospectively identified on SISES.SISES significantly improves the specificity in the diagnosis of endometrial lesions. False-negative findings of SISES in polyps in postmenopausal women with bleeding suggest the need for surgical removal in this setting. © 2016 Wiley Periodicals, Inc. J Clin Ultrasound 44:416-422, 2016.

To evaluate pregnancy outcomes with low-lying placenta according to the distance from placenta to cervical os.Retrospective cohort study of singleton pregnancies with low-lying placenta (placenta edge within 20 mm of internal os on transvaginal sonography) delivered at our hospital from 2002 to 2012, excluding suspected placenta accreta and vasa previa. Vaginal delivery was offered in the absence of another indication for cesarean. Outcomes were stratified according to placenta-os distance ≤10 mm and 11-20 mm.Of 98 pregnancies with low-lying placenta, 41% had placenta-os distance ≤10 mm and 59% placenta-os distance 11-20 mm. Fifty-four percent had a trial of labor. Six (15%) with placenta-os ≤10 mm and 21 (36%) with placenta-os 11-20 mm delivered vaginally, p = 0.02. Bleeding necessitating cesarean occurred in 25%, and postpartum hemorrhage in 43%; neither complication associated with placenta-os distance. Third-trimester bleeding prior to delivery hospitalization was reported in 44% and associated with later bleeding requiring cesarean in 51% versus 4% of those without third-trimester bleeding, p 0.001.Whereas low-lying placenta does not contraindicate labor, we found significant risk for bleeding complications, regardless of the planned mode of delivery. Placenta-os distance did not significantly affect outcomes in our series.

Objectives The purpose of this study was to evaluate the association between first-trimester sonographic findings and morbidly adherent placenta at delivery. Methods We conducted a retrospective review of all first-trimester sonographic examinations from pregnancies that underwent third-trimester sonography for placenta previa or low-lying placenta between September 1997 and October 2011. Only women with a prior cesarean delivery were included. Transabdominal and transvaginal images from these first-trimester studies were reviewed for the following sonographic parameters: distance from the inferior border of the gestational sac to the external cervical os, location of the decidua basalis, presence of anechoic areas, uterine-bladder interface irregularity, and smallest anterior myometrial thickness. Morbidly adherent placentation was confirmed on histologic examination of hysterectomy specimens. Statistical methods included univariate and multivariate analyses. Results Thirty-nine patients met inclusion criteria, of whom 14 (36%) had confirmed placental invasion. The number of prior cesarean deliveries was significantly associated with placental invasion (P < .0001). The only first-trimester sonographic finding associated with invasion was the smallest anterior myometrial thickness measured in the sagittal plane (P< .02). Multivariate analysis based on these two variables yielded an area under the receiver operating characteristic curve of 0.94 (95% confidence interval, 0.87–1.00) and significantly improved the prediction of placental invasion compared to using the number of prior cesarean deliveries alone. Conclusions In women with persistent placenta previa or low-lying placenta and prior cesarean delivery, the smallest anterior myometrial thickness on first-trimester sonography significantly improved detection of morbidly adherent placenta.

Objective To evaluate the incidence of vaginal bleeding in women with placenta accreta according to gestational age at delivery. Methods This is a retrospective cohort study of women with prior cesarean delivery and persistent placenta previa delivered at our institution between December 1997 and December 2011. Diagnosis of invasion was based on hysterectomy performed for an abnormally adherent placenta with histologic confirmation. Suspicion for invasion was based on the impression of the attending physician at the time of ultrasonography. Records were reviewed to identify indication for delivery and estimated blood loss. Statistical analyses were performed using Student's t test, χ2 test, and Mantel-Haenszel and Jonckheere-Terpstra tests for trend. Results Of 216 women with prior cesarean delivery and persistent previa, 65 (30%) required cesarean hysterectomy and had histologic confirmation of invasion. Urgent delivery for bleeding was performed in 20% of these pregnancies (13/65). Delivery for bleeding decreased significantly with advancing gestation (P=.001). In our series, 71% with accreta were delivered at 36 weeks of gestation or greater with delivery for bleeding in five (11%), and estimated blood loss was not increased in these pregnancies. Of 79 women with ultrasonographic suspicion for accreta, the incidence of vaginal bleeding prompting urgent delivery also decreased with advancing gestation (P Conclusion Likelihood of vaginal bleeding necessitating delivery declined with advancing gestation in pregnancies with placenta accreta as did blood loss. Most were delivered at 36 weeks of gestation or greater, nearly 90% in the absence of bleeding complications. Thus, although preterm delivery is an important consideration when placenta accreta is suspected, our findings support individualizing delivery planning.

The purpose of this study was to evaluate neural tube defect (NTD) detection according to whether serum alpha-fetoprotein (AFP) screening or standard ultrasound are performed.Prenatal and neonatal datasets were reviewed to identify pregnancies with NTDs from 1 institution between January 2000 and December 2003. AFP screening was offered21 weeks and considered elevated ifor = 2.50 multiples of the median. Standard ultrasound was performed for specific indications in low-risk pregnancies.There were 66 NTDs, 1 per 950 deliveries. AFP sensitivity was 65%. If the gestational age used for AFP calculation was confirmed with ultrasound, sensitivity improved to 86%. The sensitivity of standard ultrasound was 100%, P.001 compared with AFP screening. NTDs detected with standard ultrasound were identified later in gestation, as examinations were performed for other indications.Standard ultrasound improved NTD detection over AFP screening alone, by improving AFP test sensitivity and identifying NTDs in low-risk pregnancies.

The purpose of this study was to describe levator ani (LA) anatomy in postterm nulliparas using 3-dimensional (3-D) magnetic resonance (MR).Nulliparas (n = 84) with uncomplicated, postterm pregnancies underwent an MR (4 mm slices, 0 gap) of the uterus and pelvis. LA volume and morphometry were assessed using 3-D post-processing software.LA insertion into the symphysis was visible in 93%, and the iliococcygeus muscle assumed a convex shape (arch) in the 92% of the 84 women. The LA shape was characterized as "U" in 53% and "V" in 47%. Mean LA volume was 13.5 (3.7) cm3. There was a positive association between LA volume and higher fetal station (P = .02) and increasing BMI (P.001). However, no relationship between LA volume and station was found after adjusting for BMI.BMI was correlated with LA volume in postterm nulliparas. LA insertion into the symphysis and the iliococcygeus arch were well-preserved overall and morphometry was variable.

Objective To study whether magnetic resonance imaging (MRI) pelvimetry has the ability to identify those women who require cesarean delivery for labor dystocia. Methods From July 2003 to April 2004, nulliparous women scheduled for a labor induction for prolonged pregnancy (42 weeks) were asked to participate in a pelvimetry study. Those who consented underwent fast-acquisition MRI that included two 90-second acquisitions to evaluate fetal biometry and volumetry and maternal pelvimetry, including novel measurements of pelvic bony and soft tissue volumes as determined by MRI. Information about each patient's pregnancy, labor course, and neonatal outcome was prospectively collected. Pelvimetry results for those women undergoing operative delivery for labor dystocia were compared with those who did not. Single fetal and maternal pelvic measurements, as well as ratios of both, were analyzed. In addition, previously described radiographic pelvimetry techniques and formulas to predict dystocia were used. Results One hundred one women underwent MRI, and 22 of these underwent cesarean delivery for dystocia. No single fetal measurement was statistically associated with dystocia. Several maternal pelvic measures, fetal-to-maternal ratios, and previously reported pelvimetric techniques were significantly associated with dystocia. The ratio of magnetic resonance (MR) fetal head volume to pelvic soft tissue volume had statistical significance (P = .04). Receiver operator characteristic curves were developed for the different measurements, ratios, and formulas studied to assess whether any of the techniques could accurately predict labor dystocia requiring operative delivery. The area under the curve values ranged from 0.6 to 0.8, with the ratio of MR head volume to pelvic soft tissue being 0.7. These values suggest that MRI can identify those women at greatest risk for dystocia, but it cannot with accuracy predict which ones will require a cesarean. Conclusion We found significant associations with MRI pelvimetry and labor dystocia, but MRI was not a significant improvement over previously described pelvimetric techniques. Level of evidence II-3.

To determine the effect of a 6 gram intravenous bolus of magnesium sulfate on maternal cerebral blood flow in women with preeclampsia.Velocity-encoded phase-contrast magnetic resonance imaging studies were performed on twelve preeclamptic women prior to and immediately after infusion of a 6 gram magnesium sulfate loading dose. Cerebral blood flow was determined at the bilateral proximal middle and posterior cerebral arteries. Study participants returned 6 weeks postpartum for a non-pregnant measurement of cerebral blood flow. The Wilcoxon paired-sample test was used with statistical significance defined as p0.05.There was no significant difference in cerebral vessel diameter nor blood flow for any of the examined arteries between the pre- and post magnesium sulfate therapy states.The absence of a significant difference in cerebral blood flow of the middle and posterior cerebral arteries before and after infusion of a 6 gram loading dose of magnesium sulfate in women with preeclampsia could suggest the absence of vasoconstriction of the large cerebral arteries in preeclampsia and question the role of magnesium sulfate as a vasodilator of these arteries.

Objective: The purpose of this study was to compare the relationship between the actual amnionic fluid volume that was measured at delivery and magnetic resonance amnionic fluid volume determination, largest vertical pocket, and amnionic fluid index. Study design: Three hours before cesarean delivery, 80 women had sonographic measurement of the amnionic fluid index and the largest vertical pocket. Magnetic resonance imaging was then completed, and the magnetic resonance amnionic fluid volume was determined. At surgery, the amnionic fluid was collected. Pearson correlations were determined. Receiver operating characteristic curves were developed for each method as a measure of predictability for oligohydramnios. Results: The correlations for the magnetic resonance amnionic fluid volume, amnionic fluid index, and largest vertical pocket to amnionic fluid volume was 0.84, 0.77, and 0.71, respectively. Magnetic resonance amnionic fluid volume has a statistically higher correlation than the largest vertical pocket (P = .046). The 3 methods, however, are statistically comparable for identifying oligohydramnios. Conclusion: Magnetic resonance imaging is comparable with ultrasound evaluation for the prediction of oligohydramnios. Correlations to actual amnionic fluid volume are also comparable.

Objective: The purpose of this study was to compare third trimester and nonpregnant cerebral blood flow of women with preeclampsia to normotensive control subjects with the use of magnetic resonance imaging techniques.Study design: Nine normotensive pregnant women and 12 untreated women with preeclampsia underwent velocity-encoded phase contrast magnetic resonance imaging of the bilateral middle and posterior cerebral arteries in the third trimester and at 6 to 8 weeks after delivery. The Student t test was used for comparison, with a probability value ofResults: Third-trimester large cerebral artery blood flow was significantly higher in preeclampsia. Mean vessel diameter was unchanged, except for the left posterior cerebral artery. There was no difference in mean vessel diameter or cerebral blood flow between the 2 groups while the women were not pregnant.Conclusion: Cerebral blood flow is increased significantly in preeclampsia. We hypothesize that increased cerebral blood flow ultimately could lead to eclampsia through hyperperfusion and the development of vasogenic edema. (C) 2004 Elsevier Inc. All rights reserved.

The purpose of this study was to determine whether differences are seen in calculation of fetal weight using 5-mm sagittal, 3-mm coronal, and 8-mm axial MRI acquisitions compared with term birth weight and contemporaneous sonography.Fetal volume measurements were obtained from MRI acquisitions as follows: 5-mm sagittal (2 acquisitions), 3-mm coronal (2 acquisitions), and 8-mm axial (1 acquisition). A 90-sec single-shot fast spin-echo sequence was used. MRI and sonographic studies for fetal weight estimates were performed within 3 hr of term delivery. MRI calculation was based on the equation 0.12 + 1.031 x fetal volume (fetal area x slice thickness) (mL) = MRI fetal weight (kg). The sonographic fetal weight estimate was calculated using the Hadlock formula. MRI and sonographic calculations were compared with birth weight. Concordance coefficient analysis was performed.Thirty-five retrospective fetal calculations were performed. Concordance coefficients, gram weight means and standard deviations (mean +/- SD) between birth weight and MRI acquisitions were as follows: 8-mm axial, 0.91 (3,554 +/- 431 g); 3-mm coronal, 0.84 (3,752 +/- 578 g); and 5-mm sagittal, 0.83 (3,685 +/- 567 g), compared with 0.78 (3,518 +/- 332 g) for sonography. The MRI axial concordance coefficient was significantly different from that of the sonographic estimates (p = 0.05). MRI axial concordance coefficient was not statistically different from that of the MRI coronal concordance coefficient (p = 0.22) or the MRI sagittal concordance coefficient (p = 0.19).Calculated weights from a 90-sec single-shot fast spin-echo sequence MR acquisition with 8-mm-thick slices in the axial plane at term are better than sonographic estimates.

This study was undertaken to determine blood flow changes in the large cerebral arteries during normal pregnancy.Ten healthy pregnant volunteers underwent velocity-encoded phase contrast magnetic resonance imaging at 4 time intervals: 14 to 16, 28 to 32, and 36 to 38 weeks' gestation, and at 6 to 8 weeks' postpartum. Analysis consisted of serial paired Student t tests, with P.05 considered significant.By using postpartum values for comparison, cerebral blood flow decreased by 14 to 16 weeks in the middle cerebral artery (P.001), but was not significantly changed in the posterior cerebral artery. Significant decreases occurred in both the middle (P.0001) and posterior (P=.002) cerebral arteries in late pregnancy.An approximately 20% reduction in large artery cerebral blood flow occurs during normal pregnancy, secondary to changes in velocity, whereas the area of these vessels remains unchanged. These findings may represent generalized vasodilatation of downstream resistance arterioles, assuming constant blood flow at the tissue level.

Objective This study was undertaken to compare magnetic resonance (MR) and ultrasound (US) fetal weight estimates obtained immediately before delivery with birth weight. Study design Eighty women scheduled for a cesarean delivery underwent a fast acquisition MR and US for fetal weight estimation within 3 hours of delivery. Prospective MR calculation was based on the equation 0.12+1.031 g/mL×fetal volume (mL)=MR weight (g). US fetal weight estimation was calculated by the formula by Hadlock et al. Estimations were compared with birth weight. Results Correlation (95% CI) between birth weight and MR weight is 0.95 with a mean absolute error of 129 g (105–155) compared with the correlation between birth weight and US of 0.85 with a mean absolute error of 225 g (186–264). The correlation for birth weight and MR imaging is significantly greater than that of birth weight and US, P Conclusion Birth weight estimation is more accurate by MR imaging than by US in term infants.

To determine which non-biometric components of the ultrasound fetal survey can routinely be seen on a single fast acquisition magnetic resonance (MR) sequence aligned axial to the maternal uterus.The non-biometric components of the routine fetal ultrasound examination were applied retrospectively to the initial MR single-shot fast spin-echo acquisition aligned axial to the maternal uterus in the normal fetus to determine whether these parameters could be routinely evaluated. Nineteen women with anatomically normal fetuses had a total of 31 MR studies performed for fetal or maternal indications, either as part of an indicated examination or as part of a study protocol approved by the institutional review board. The images in these 31 MR studies were reviewed by two independent examiners who were blinded to the other's assessment; concordance was necessary for a component to be adequately assessed. The Wilcoxon rank sum test was used to determine the effect of gestational age and fetal lie on the ability to assess non-biometric parameters.Assessment was possible in 85% of the non-biometric parameters. Cord insertion, external genitalia and the four-chamber view of the heart were most problematic. In only two cases was the four-chamber view of the heart identified. Longitudinal lie allowed significantly more parameters (82%) to be evaluated than transverse lie (45%) (p0.003). No difference based on gestational age was found.A single fast acquisition axial MR sequence can evaluate 85% of the non-biometric components of the fetal ultrasound survey. Fetal lie is an important confounder in the ability to resolve fetal anatomy with a single MR axial uterine acquisition.

To carry out a prospective study of Doppler velocimetry of the fetomaternal circulation in women with chronic hypertension, to evaluate whether the subsequent development of superimposed pre-eclampsia can be predicted.Serial Doppler studies of the maternal uterine and renal arteries, and fetal middle cerebral and umbilical arteries, were performed at 16-20 and at 28-32 weeks' gestation in 56 women with chronic hypertension. Pulsatility indices were compared using the Wilcoxon rank sum method. A p value of0.05 was considered significant.Uterine artery impedance was significantly elevated as early as 16-20 and at 28-32 weeks' gestation, while the cerebroplacental ratio was lower at 28-32 weeks' gestation, in the 14 women who developed superimposed pre-eclampsia. The maternal renal artery impedance remained constant throughout gestation, regardless of the development of pre-eclampsia.Uterine artery Doppler velocimetry at 16-20 and at 28-32 weeks' gestation showing increased impedance is predictive for the development of superimposed pre-eclampsia in women with chronic hypertension. The cerebroplacental ratio suggested early fetal brain sparing at 28-32 weeks' gestation in these women.

Our purpose was to evaluate the ventricular atria and cisterna magna in fetuses with and without suspected central nervous system (CNS) anomalies by magnetic resonance (MR).Measurements of the right and left ventricular atria and cisterna magna were obtained by MR in two groups: those with and without CNS anomalies. Published mean ultrasound measurements of the far field atrium were compared with MR.MR measurements were obtained in 23 fetuses without and 37 fetuses with CNS anomalies. Atrial measurements were independent of gestational age in healthy subjects. MR atrial widths were larger in abnormal compared with normal subjects (P.05). The atrial cutoff value derived by 2 SDs above the mean with MR is 10 mm. MR cisterna magna measurements increased with gestational age (P =.005).The cutoff value for ventriculomegaly on MR is10 mm. MR cisterna magna measurements are dependent on gestational age. Both ventricular atria and cisterna magna are readily measured with MR.

We sought to apply a standardized evaluation of ultrasound parameters for the prediction of placental invasion in a high-risk population.This was a retrospective review of gravidas with ≥1 prior cesarean delivery who received an ultrasound diagnosis of placenta previa or low-lying placenta in the third trimester at our institution from 1997 through 2011. Sonographic images were reviewed by an investigator blinded to pregnancy outcome and sonography reports. Parameters assessed included loss of retroplacental clear zone, irregularity and width of uterine-bladder interface, smallest myometrial thickness, presence of lacunar spaces, and bridging vessels. Diagnosis of placental invasion was based on histologic confirmation. Statistical analyses were performed using linear logistic regression and multiparametric analyses to generate a predictive equation evaluated using a receiver operating characteristic curve.Of 184 gravidas who met inclusion criteria, 54 (29%) had invasion confirmed on hysterectomy specimen. All sonographic parameters were associated with placental invasion (P.001). Constructing a receiver operating characteristic curve, the combination of smallest sagittal myometrial thickness, lacunae, and bridging vessels, in addition to number of cesarean deliveries and placental location, yielded an area under the curve of 0.87 (95% confidence interval, 0.80-0.95). Using logistic regression, a predictive equation was generated, termed the "Placenta Accreta Index." Each parameter was weighted to create a 9-point scale in which a score of 0-9 provided a probability of invasion that ranged from 2-96%, respectively.Assignment of the Placenta Accreta Index may be helpful in predicting individual patient risk for morbidly adherent placenta.

Objective: The aim of this study was to describe Doppler velocimetric findings in pregnancies complicated by the twin reversed-arterial perfusion sequence and to determine the association of these findings with pregnancy outcome. Study Design: Six twin pregnancies complicated by twin reversed-arterial perfusion sequence had ultrasonographic and Doppler studies performed between 1990 and 1997. Pulsatile vessels in the umbilical cords of the pump and acardiac twins were insonated, and reversal of flow was confirmed in all cases. Resistive index values were calculated, and the difference in resistive index between the pump and acardiac twin in each pair was evaluated as a marker of pregnancy outcome. Results: Five of 6 pump twins survived the immediate neonatal period. Although 5 of the acardiac twins had abnormally elevated Doppler index values, no ratio of systolic to diastolic velocity or resistive index value of the acardiac twin alone was associated with either a good or poor prognosis for the pump twin. Among the 3 pump twins with good outcomes, all had a resistive index difference >0.20. Among the 3 pump twins with poor outcomes, all had small resistive index differences ( Conclusion: We found larger differences in resistive index to be associated with improved outcome of the pump twin in pregnancies complicated by twin reversed-arterial perfusion sequence. Smaller resistive index differences were associated with poor outcome, including cardiac failure and central nervous system hypoperfusion. (Am J Obstet Gynecol 2001;185:135-9.)

Objectives: Our aim was to evaluate the utility of color flow mapping in the prediction of placental myometrial invasion in women with Cesarean delivery.Methods: Ultrasound color flow mapping was performed on placental implantations in potential proximity to the hysterotomy scar. The smallest myometrial thickness was measured under the placenta to evaluate the degree of myometrial attenuation in this area and note was made of unusual vascular lakes.Results: Two hundred fifteen women with placentas in proximity to the prior hysterotomy scar underwent color Doppler mapping. Of 20 women with placenta previa and Cesarean delivery, 15 had Cesarean hysterectomy for bleeding complications and nine had the pathological diagnosis of placental invasion. The measurement of < 1 mm for the smallest myometrial thickness or presence of large intraplacental lakes was predictive of myometrial invasion (sensitivity 100%, specificity 72%, PPPV 72%, and NPV 100%).Conclusions: Color flow mapping predicted myometrial invasion ...

Objective: Our purpose was to assess whether antepartum oligohydramnios is associated with adverse perinatal outcomes. Study Design: Women delivered between July 1, 1991, and September 30, 1996, who underwent ultrasonography at ≥34 weeks' gestation were analyzed. Oligohydramnios was defined as an amniotic fluid index ≤50 mm. Perinatal outcomes in pregnancies with oligohydramnios were compared with those with an amniotic fluid index of >50 mm. Results: In our analysis of 6423 pregnancies, 147 (2.3%) were complicated by oligohydramnios. This complication was associated with increased labor induction (42% vs 18%; P P P P P P Conclusion: Antepartum oligohydramnios is associated with increased perinatal morbidity and mortality. (Am J Obstet Gynecol 2000;182:909-12.)

Objective: To determine if unexplained changes in the amniotic fluid index or pulsatility indices of the fetal renal, middle cerebral, or umbilical artery are predictive of perinatal outcome in pregnancies complicated by oligohydramnios.Methods: Changes in amniotic fluid measurements and fetal vessel velocimetry in patients with oligohydramnios were evaluated for correlation with fetal outcome. Fourteen fetuses with oligohydramnios underwent serial sonography evaluating the amniotic fluid index and fetal middle cerebral, renal, and umbilical velocimetry. Matched controls and neonatal outcomes were obtained.Results: Change in amniotic fluid index and in renal artery pulsatility index were inversely correlated. Change in the middle cerebral artery pulsatility index was different in infants with normal outcome compared to infants with advetse outcomeConclusions: Serial velocimetry of the middle cerebral artery may identify fetuses with oligohydramnios at risk for adverse outcomes.

Objective: To describe the anatomic and technical difficulties encountered with transvaginal ultrasound imaging of the cervix in a consecutive series of women at risk for preterm delivery. Methods: Three groups of women had cervical ultrasound examinations: those with histories of preterm birth, those with incompetent cervices, and those admitted for preterm labor that did not progress. Standardized ultrasound examinations of the cervix involved measuring the length of the endocervical canal, funneling length, and internal os dilation with and without fundal pressure. Results: Sixty consecutive women had transvaginal ultrasound examinations for assessment of the cervix. Forty-six had histories of preterm birth, five had incompetent cervices, and nine had arrested preterm labor. Six types of problems arose, which can be divided into anatomic or technical considerations, with an overall frequency of 27% (95% confidence interval 16%, 40%). Anatomic pitfalls that hampered identification of the internal os included an undeveloped lower uterine segment (n = 5), a focal myometrial contraction (n = 1), rapid and spontaneous cervical change (n = 1), and an endocervical polyp (n = 1). Technical pitfalls included incorrect interpretation of internal os dilation because of vaginal probe orientation (n = 7) and artificial lengthening of the endocervical canal because of distortion of the cervix by the transducer (n = 1). Conclusion: We caution those who perform cervical length examinations to be wary of falsely reassuring findings due to potential anatomic and technical pitfalls.

The patient is a 20 year old gravida 2 para 1 Hispanicwoman who was referred for ultrasonographic eval-uation because of uterine size less than expected fordates. Her previous child is healthy. She was in anonconsanguineous relationship.Antenatal ultrasonography revealed fetal biomet-ric data consistent with a 16 week singleton gesta-tion. The amount of amniotic fluid was normal.Multiple fetal anomalies were noted, including scalpand hand edema with redundant skin and bilateralcystic hygromas extending along the spine (Fig. 1). Adiaphragmatic hernia was noted with dextropositionof the heart secondary to mass effect. The stomachwas in the fetal thorax (Fig. 2). The kidneys wereechogenic (Fig. 3). Amniocentesis was performed,which subsequently documented a normal femalekaryotype. Amniotic fluid alpha-fetoprotein levelswere normal.A follow-up ultrasonogram was obtained 3 weekslater, after the final results of the amniocentesis wereavailable. Fetal growth as assessed with biometricswas now consistent with an 18 week gestation. Againthe diaphragmatic hernia, echogenic kidneys, andcystic hygroma were noted. The amniotic fluid vol-ume was now low normal with the largest pocketmeasuring 38 mm. At this time cardiac evaluationwas performed and a small aortic outflow tract, smallleft ventricle, mediastinal shift, and ventriculoseptal

Glenoid dysplasia is an anomaly of the scapula characterized by underdevelopment of the bony glenoid and adjacent part of the scapular neck which may be seen as a primary isolated condition, in patients with multiple anomalies or ill-defined syndromes, in well-described syndromes, in mucopolysaccharidoses and related conditions, and in certain skeletal dysplasias. The general subject of glenoid dysplasia is reviewed with reference to descriptions in the literature and personal observations.