Ryan Longman

Washington University in St. Louis, San Luis, Missouri, United States

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Publications (23)84.63 Total impact

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    ABSTRACT: Objective To estimate the rate and risk of appendix non-visualization and alternative diagnoses made with MRI for suspected appendicitis in pregnant women. Study design We performed a retrospective cohort study of consecutive pregnant women who underwent MRI for suspected appendicitis at a single center from 2007-2012. Data on clinical presentation, imaging, and surgical pathology were extracted from electronic medical records. Odds ratios estimated risk factors for non-diagnosis. Radiologic diagnoses were identified and rates of diagnoses calculated. Subgroup analysis was performed among women who underwent initial imaging with ultrasound. Results Over the 5-year period, 171 pregnant women underwent MRI for suspected appendicitis. The rate of non-visualization was 30.9% (n=53). Of the remaining 118 women with a visualized appendix, 18 had imaging findings consistent with appendicitis and underwent appendectomy. Twelve cases of appendicitis were confirmed on pathology (66.7%). Women with non-visualization of the appendix on MRI were more likely to be beyond the first trimester (OR 2.1, 95% CI 1.0-4.5). Seventy-four women had pathology diagnosed on MRI (43.3%). In the group of 43 women who had a non-diagnostic ultrasound prior to MRI, the rate of subsequent diagnostic MRI was 65% (n=28). Conclusions MRI yields a high diagnostic rate and accuracy in pregnant women with suspected appendicitis, and also provides alternative diagnoses to guide further management. Given the high rate of appendix non-visualization on ultrasound reported in the literature, we recommend MRI as the imaging modality of choice for this population in settings where MRI is readily available.
    American Journal of Obstetrics and Gynecology 10/2014; 212(3). DOI:10.1016/j.ajog.2014.10.002 · 4.70 Impact Factor
  • S.N. Conner · M.G. Tuuli · R.E. Longman · A.O. Odibo · G.A. Macones · A.G. Cahill ·

    Obstetric Anesthesia Digest 09/2014; 34(3):170-171. DOI:10.1097/01.aoa.0000452186.16909.62
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    ABSTRACT: When congenital anomalies are diagnosed on prenatal ultrasound, the current standard of care is to perform G-banded karyotyping on cultured amniotic cells. Chromosomal microarray (CMA) can detect smaller genomic deletions and duplications than traditional karyotype analysis. CMA is the first-tier test in the postnatal evaluation of children with multiple congenital anomalies. Recent studies have demonstrated the utility of CMA in the prenatal setting and have advocated for widespread implementation of this technology as the preferred test in prenatal diagnosis. However, CMA remains significantly more expensive than karyotype. In this study, we performed an economic analysis of cytogenetic technologies in the prenatal diagnosis of sonographically detected fetal anomalies comparing four strategies: (i) karyotype alone, (ii) CMA alone, (iii) karyotype and CMA, and (iv) karyotype followed by CMA if the karyotype was normal. In a theoretical cohort of 1,000 patients, CMA alone and karyotype followed by CMA if the karyotype was normal identified a similar number of chromosomal abnormalities. In this model, CMA alone was the most cost-effective strategy, although karyotype alone and CMA following a normal karyotype are both acceptable alternatives. This study supports the clinical utility of CMA in the prenatal diagnosis of sonographically detected fetal anomalies. © 2014 Wiley Periodicals, Inc.
    American Journal of Medical Genetics Part A 05/2014; 164(5). DOI:10.1002/ajmg.a.36435 · 2.16 Impact Factor
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    ABSTRACT: To estimate the association between antenatal bowel dilation and postnatal small bowel atresia in fetal gastroschisis and to establish a threshold at which the risk of adverse neonatal outcomes increases. A retrospective cohort study of singleton gestations with an antenatal diagnosis of gastroschisis seen in our ultrasound unit from 2001-2010. Stored images were reviewed, blind to postnatal diagnoses and outcomes, from the last ultrasound exam before delivery. Fetal intra- and extra-abdominal bowel dilation as well as bowel wall thickness was measured. Previously published definitions of bowel dilation including >6 mm, >10 mm, >14 mm, and >18 mm were evaluated for association with the primary outcome of bowel atresia. The optimal threshold to define fetal bowel dilation was determined by evaluating the significance of association as well as test performance characteristics. Of 109 consecutive patients with fetal gastroschisis, there were 4 cases of intrauterine fetal demise and 3 neonatal deaths. Of the 94 live births with complete outcome data, 39 (41.5%) had measurable intra-abdominal bowel dilation (IABD). There were 14 (14.9%) cases of bowel atresia. Using a threshold of >14 mm, IABD was significantly associated with an increased risk for bowel atresia (RR 3.1, 95% CI 1.2-8.2) with a sensitivity of 57.1%, specificity of 75.0%, positive predictive value of 28.6%, and negative predictive value of 90.9%. IABD >14 mm was also associated with a significantly longer NICU length of stay. There was no significant association between extra-abdominal bowel dilation and bowel atresia at any of the thresholds evaluated. IABD >14 mm is associated with an increased risk for postnatal bowel atresia in fetal gastroschisis. This finding may be useful in counseling patients regarding the anticipated postnatal course for their neonate.
    Ultrasound in Obstetrics and Gynecology 04/2014; 43(4). DOI:10.1002/uog.12568 · 3.85 Impact Factor
  • Shayna N. Conner · Ryan E. Longman · Alison G. Cahill ·
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    ABSTRACT: The use of ultrasound in the prenatal diagnosis of fetal genetic syndromes is rapidly evolving. Advancing technology and new research findings are aiding in the increased accuracy of ultrasound-based diagnosis in combination with other methods of non-invasive and invasive fetal testing. Ultrasound as a screening tool for aneuploidy and other anomalies is increasingly being used throughout pregnancy, beginning in the first trimester. Given the number of recorded syndromes, it is important to identify patterns and establish a strategy for identifying abnormalities on ultrasound. These syndromes encompass a wide range of causes from viral, substance-linked, chromosomal, and other genetic syndromes. Despite the ability of those experienced in ultrasound, it is important to note that not all fetal genetic syndromes can be identified prenatally, and even common syndromes often have no associated ultrasound findings. Here, we review the role of ultrasound in the diagnosis of fetal genetic syndromes.
    Best practice & research. Clinical obstetrics & gynaecology 04/2014; 28(3). DOI:10.1016/j.bpobgyn.2014.01.005 · 1.92 Impact Factor
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    ABSTRACT: To compare maternal and neonatal infectious morbidity following cesareans performed in the second and first stages of labor. We conducted a retropective cohort study of all consecutive, singleton, term, cesarean deliveries in laboring women in a single institution from 2005 - 2012. Second stage cesareans were defined as those performed at complete cervical dilation (10 cm) and first stage cesareans were those performed before 10 cm cervical dilation. The primary outcome was endometritis. Rates of infectious morbidity were compared in the two groups. Multivariable logistic regression was used to calculate adjusted risk estimates. Of 2,505 cesareans meeting inclusion criteria, 400 (16.0%) were performed in the second stage while 2,105 (84.0%) were performed in the first stage of labor. The risk of endometritis was nearly 3-fold higher in second compared to first stage cesareans (4.25% vs 1.52%, crude OR 2.88 [95% CI 1.58, 5.23]). The risk remained significantly higher after controlling for confounders (adjusted OR 2.78 [95% CI 1.51, 5.09]). Second stage cesarean is associated with increased risk of endometritis compared to first stage cesarean. Further studies will determine if different infection preventive strategies are needed at second stage cesareans to reduce endometritis.
    American journal of obstetrics and gynecology 03/2014; 211(4). DOI:10.1016/j.ajog.2014.03.040 · 4.70 Impact Factor

  • American Journal of Obstetrics and Gynecology 01/2014; 210(1):S105-S106. DOI:10.1016/j.ajog.2013.10.224 · 4.70 Impact Factor

  • American Journal of Obstetrics and Gynecology 01/2014; 210(1):S272-S273. DOI:10.1016/j.ajog.2013.10.585 · 4.70 Impact Factor

  • American Journal of Obstetrics and Gynecology 01/2014; 210(1):S158-S159. DOI:10.1016/j.ajog.2013.10.337 · 4.70 Impact Factor
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    ABSTRACT: Ectopic complete molar pregnancy in the ovary is an exceptionally rare event. Here we present a case of ovarian complete hydatidiform mole in a 20-year-old gravida 2 para 1 woman. At presentation, the patient underwent excision of a hemorrhagic left ovarian cyst, with routine sections demonstrating a hemorrhagic corpus luteum with a single microscopic focus of detached atypical trophoblast, without chorionic villi. Subsequent left salpingo-oophorectomy for persistently elevated human chorionic gonadotropin led to a final diagnosis of complete hydatidiform mole arising in the ovary. The fallopian tube was unremarkable. Zygosity was determined using short tandem repeat analysis, confirming the diagnosis of monospermic complete mole. In the clinical setting of a markedly elevated human chorionic gonadotropin level and an ovarian mass, histopathologic examination is critical in distinguishing ectopic pregnancy from choriocarcinoma. Short tandem repeat analysis can be a useful adjunct to histologic diagnosis in challenging cases.
    Human pathology 10/2013; 44(12). DOI:10.1016/j.humpath.2013.07.027 · 2.77 Impact Factor
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    ABSTRACT: Objective: The purpose of this study was to test the hypothesis that increasing body mass index (BMI) is associated with increased time from skin incision to infant delivery and increased neonatal morbidity at cesarean delivery. Study design: We performed a retrospective cohort study of all cesarean deliveries that occurred at 1 institution from 2004-2008. Four comparison groups were defined by BMI of <30 kg/m(2) (n = 668 women), 30-39.9 kg/m(2) (n = 1002 women), 40-49.9 kg/m(2) (n = 403 women), or ≥50 kg/m(2) (n = 193 women). The primary outcome was time from skin incision to infant delivery. Secondary outcomes were a composite measure of neonatal morbidity and its individual components: 5-minute Apgar score <7, umbilical cord arterial pH <7.10 and <7.20, umbilical cord arterial base excess ≤8 mmol/L, special care nursery admission, and neonatal intensive care unit admission. Results: Increasing BMI was associated with significantly increased time from skin incision to infant delivery, which demonstrated a dose-response pattern. Minutes from skin incision to delivery of the infant by BMI strata were 9.4 ± 5.9 for <30 kg/m(2), 11.0 ± 6.8 for 30-39.9 kg/m(2), 13.0 ± 8.0 for 40-49.9 kg/m(2), and 16.0 ± 11.3 for ≥50 kg/m(2) (P < .01). Composite neonatal morbidity was significantly higher with increasing BMI: 23.0% for <30 kg/m(2), 25% for 30-39.9 kg/m(2), 29.8% for 40-49.9 kg/m(2), and 32.1% for ≥50 kg/m(2) (P = .02). Conclusion: Increasing BMI is associated with a significantly increased time from skin incision to infant delivery and neonatal morbidity. Cesarean delivery technique remains to be optimized for obese women.
    American journal of obstetrics and gynecology 05/2013; 209(4). DOI:10.1016/j.ajog.2013.05.054 · 4.70 Impact Factor
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    ABSTRACT: Objectives: The aim of this study was to estimate the incidence of single umbilical artery (SUA) in twin pregnancies and to investigate whether SUA in twin gestations is associated with adverse obstetric outcomes. Methods: We performed a retrospective cohort study of consecutive twin pregnancies over 17 years at a tertiary care hospital. Primary exposure was SUA in one or both twins documented at routine second trimester anatomic survey. Adverse obstetric outcomes included small for gestational age (SGA), placental abruption, and preterm birth, evaluated in univariable and multivariable analyses. Analysis was performed both at the pregnancy level and at the fetal level using paired analyses to account for the non-independence of twin pairs. Results: Of the 2378 twin pregnancies without major anatomic abnormalities, 1.7% (n = 40) had SUA. Only one pregnancy (one monochorionic twin pair) was complicated by both twins having SUA. Twin fetuses with SUA are at increased risk for SGA (aOR = 2.1 (1.2-4.1), p = 0.03) after adjusting for pertinent confounding factors, similar to the findings of previous studies in singleton pregnancies. In addition, twins with SUA may be at increased risk for preterm delivery before 28 weeks compared with twin pregnancies with normal three-vessel umbilical cords (adjusted odds ratio (aOR) 3.2 (1.3-7.89.4), p = 0.01). Conclusions: The incidence of SUA in twin gestations in this cohort is significantly less than the recently published data. Similar to reports in singleton gestations, SUA appears to be associated with an increased risk for SGA in twins.
    Prenatal Diagnosis 03/2013; 33(3). DOI:10.1002/pd.4057 · 3.27 Impact Factor

  • American Journal of Obstetrics and Gynecology 01/2013; 208(1):S342. DOI:10.1016/j.ajog.2012.10.154 · 4.70 Impact Factor
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    ABSTRACT: Objective: Uterine fibroid tumors have been associated with adverse outcomes in singleton pregnancies. We aimed to estimate risk for adverse obstetric outcomes that are associated with fibroid tumors in twin pregnancies. Study design: A retrospective cohort study of twin pregnancies with ≥1 fibroid tumor on second trimester ultrasound examination. Outcomes included small-for-gestational-age fetal growth, preterm delivery, preterm rupture of membranes, abruption, preeclampsia, and intrauterine fetal death. Univariable and multivariable analyses were used to evaluate the impact of fibroid tumors on outcomes in twin pregnancies compared with twin pregnancies without fibroid tumors. Results: Of 2378 nonanomalous twin pregnancies, 2.3% had fibroid tumors. Twin pregnancies with fibroid tumors were no more likely to have small-for-gestational-age growth (40.0% vs. 36.0%; adjusted odds ratio, 1.1; 95% confidence interval, 0.7-2.0) or preterm delivery at <34 weeks' gestation (25.0% vs. 24.0%; adjusted odds ratio, 1.0; 95% confidence interval, 0.5-1.9) than twin pregnancies without fibroid tumors. Other adverse outcomes were no more likely to occur in twin pregnancies with fibroid tumors than in twin pregnancies without fibroid tumors. Post hoc power calculations suggested >97% power to detect 2-fold differences in small for gestational age and preterm delivery at <34 weeks' gestation. Conclusion: In contrast to data that suggest an increased risk for adverse outcomes in singleton pregnancies with fibroid tumors, twin pregnancies with fibroid tumors do not appear to be at increased risk for complications compared with those pregnancies without fibroid tumors.
    American journal of obstetrics and gynecology 10/2012; 208(1). DOI:10.1016/j.ajog.2012.10.879 · 4.70 Impact Factor
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    ABSTRACT: To estimate the association between neural tube defects (NTDs) and low birth weight. This was a retrospective cohort study of women undergoing ultrasound from 17 to 22 weeks from 1990 to 2008. Presence or absence of fetal NTD defined the two study groups. The primary outcomes were intrauterine growth restriction (IUGR), birth weight <10th percentile, and severe IUGR <5th percentile. Subgroup analysis was performed to observe if the association with IUGR persisted. Of 66,956 women, 170 were found to have fetal NTD. Only the rate of advanced maternal age differed between the study groups. Fetuses with an NTD were at significantly increased risk for IUGR <10th percentile (adjusted odds ratio [aOR] 2.6, 95% confidence interval [CI] 1.8 to 3.9) and <5th percentile (aOR 2.8, 95% CI 1.9 to 4.3). The association persisted in subgroup analyses. Fetuses with NTD are at increased risk for IUGR, suggesting that a policy of serial growth scans in cases with isolated NTD is justified.
    American Journal of Perinatology 03/2012; 29(6):473-6. DOI:10.1055/s-0032-1304830 · 1.91 Impact Factor

  • American Journal of Obstetrics and Gynecology 01/2012; 206(1):S224-S225. DOI:10.1016/j.ajog.2011.10.512 · 4.70 Impact Factor
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    ABSTRACT: Fetal congenital heart disease may lead to abnormal fetal growth. Our objective was to estimate the association between fetal congenital heart disease (CHD) and intrauterine growth restriction (IUGR) in an effort to better inform clinical management of continuing pregnancies complicated by fetal congenital heart disease. In a retrospective cohort study, outcome data was collected from singleton pregnancies undergoing routine anatomic survey at a tertiary medical center between 1990 and 2008. Dedicated research nurses collected information on delivery outcomes in an on-going manner. Subjects with a prenatal diagnosis of fetal CHD were compared to those without CHD. Stratified analyses for isolated fetal CHD and major CHD were performed. The primary outcome was IUGR less than 10th percentile by the Alexander growth standard. Logistic regression was used to adjust for confounding variables and refine the estimates of risk. Among 67,823 patients, there were 193 cases of fetal CHD (0.3%) and 5,669 cases of IUGR (8.4%). Prenatal diagnosis of CHD was associated with an increased risk of IUGR (23.8% vs. 8.5%, adjusted odds ratio [aOR] 3.3, 95% confidence interval [CI] 2.4-4.6), and the risk was greatest in fetuses with major CHD (16.5% vs. 8.5%, aOR 2.1, 95% CI 1.3-3.2). Isolated CHD was also associated with an increased risk of IUGR (17.8% vs. 8.5%, aOR 2.2, 95% CI 1.4-3.7). Patients with a prenatal diagnosis of fetal CHD have a three-fold increase in risk of developing IUGR; patients with isolated fetal CHD are twice as likely to develop IUGR. Based on our findings, serial growth assessment may be a reasonable option for patients with fetal CHD diagnosed at routine anatomic survey.
    The journal of maternal-fetal & neonatal medicine: the official journal of the European Association of Perinatal Medicine, the Federation of Asia and Oceania Perinatal Societies, the International Society of Perinatal Obstetricians 08/2011; 25(6):662-5. DOI:10.3109/14767058.2011.597900 · 1.37 Impact Factor
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    ABSTRACT: We sought to estimate whether the presence of a maternal uterine anomaly is associated with adverse pregnancy outcomes. This retrospective cohort study included singleton pregnancies undergoing routine anatomic survey from 1990 through 2008 at a major tertiary care medical center. Pregnancies with a diagnosis of uterine anomaly (uterine septum, unicornuate uterus, bicornuate uterus, uterine didelphys) were compared to those with normal anatomy. Primary outcomes of interest were spontaneous preterm birth (PTB), breech presentation, and cesarean delivery. The presence of an anomaly was associated with PTB <34 weeks (adjusted odds ratio [aOR], 7.4; 95% confidence interval [CI], 4.8-11.4; P < .01), PTB <37 weeks (aOR, 5.9, 95% CI, 4.3-8.1; P < .01), primary nonbreech cesarean delivery (aOR, 2.6; 95% CI, 1.7-4.0; P < .01), preterm premature rupture of membranes (aOR, 3.2; 95% CI, 1.8-5.6; P < .01), and breech presentation (aOR, 8.6; 95% CI, 6.2-12.0; P < .01). Women with a uterine anomaly are at risk for PTB, highlighting an at-risk population that needs additional study for possible interventions for PTB prevention.
    American journal of obstetrics and gynecology 07/2011; 205(6):558.e1-5. DOI:10.1016/j.ajog.2011.07.022 · 4.70 Impact Factor
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    ABSTRACT: We sought to determine whether twin gestations with an anomalous fetus are at increased risk of preterm delivery or intrauterine growth restriction (IUGR) compared to twins with 2 normal fetuses. This was a retrospective cohort of twins undergoing ultrasound 15-22 weeks' gestation. Groups were defined by the presence of 1 twin with a major anomaly (discordant) or by twins with no major anomalies (normal). The primary outcomes were preterm delivery (<37 weeks) and IUGR (<10th percentile). Of 1977 twin pregnancies, 66 had a twin with a major anomaly. Preterm delivery occurred in 42 (63.6%) discordant twins, compared to 1271 (66.5%) normal twins (risk ratio, 1.0; 95% confidence interval, 0.8-1.2). IUGR was diagnosed in 15 (22.7%) normal co-twins, compared to 406 (21.3%) presenting twins in normal twins (risk ratio, 1.1; 95% confidence interval, 0.7-1.7). Twins discordant for major anomalies are not at increased risk of preterm delivery or IUGR compared to twins with no major anomalies.
    American journal of obstetrics and gynecology 07/2011; 206(1):70.e1-5. DOI:10.1016/j.ajog.2011.07.025 · 4.70 Impact Factor
  • Yan Zhong · Ryan Longman · Rachael Bradshaw · Anthony O Odibo ·
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    ABSTRACT: The purpose of this study was to compare the screening efficiency for Down syndrome using likelihood ratios versus logistic regression coefficients. We conducted a retrospective study of women at increased risk for Down syndrome referred for a second-trimester genetic sonogram. Likelihood ratios were calculated by multiplying the risk ratio from maternal serum screening by the likelihood ratios of sonographic markers. Logistic regression coefficients were calculated using a formula derived from β coefficients generated from a multivariable logistic regression model. The screening efficiency of both methods was tested in an independent population of patients. The McNemar test was used to compare the predictive ability of the two methods. In the validation population, the use of likelihood ratios had an area under the receiver operator characteristic curve of 0.90 for Down syndrome detection, whereas the use of logistic regression coefficients had an area under the curve of 0.86. Adopting a risk cutoff point of 1/270, the sensitivity of likelihood ratios was 77.4% (95% confidence interval [CI], 58.9%-90.4%) with a false-positive rate of 17.9% (95% CI, 15.0%-21.1%), whereas the sensitivity of logistic regression coefficients was 93.5% (95% CI, 78.6%-99.2%) with a false-positive rate of 34.6% (95% CI, 30.9%-38.4%). There was significant difference in screening efficiency for Down syndrome detection between the two methods (exact McNemar χ(2), P < .001 ). With a slight reduction in the Down syndrome detection rate, the use of the likelihood ratio approach was associated with a significantly lower false-positive rate compared with the logistic regression approach.
    Journal of ultrasound in medicine: official journal of the American Institute of Ultrasound in Medicine 04/2011; 30(4):463-9. · 1.54 Impact Factor