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The utility of MRI in ultrasound-detected fetal CNS abnormalities
SMFM Abstracts S241
Volume 189, Number 6 Am J Obstet Gynecol 671
THE UTILITY OF FETAL RENAL PELVIS DILATION IN DISTINGUISHING BETWEEN OBSTRUCTIVE AND NONOBSTRUCTIVE POSTNATAL HYDRONEPHROSIS JEFFREY M. DICKE1, DOUGLAS COPLEN1, 1Washington University in St. Louis, Obstetrics & Gynecology, St. Louis, MO OBJECTIVE: To determine the efficacy of current thresholds for fetal renal pelvis dilation (RPD) in identifying significant postnatal urinary tract obstruction. STUDY DESIGN: A retrospective analysis of prospectively collected measurements of fetal RPD. The entire study population consists of 287 fetuses who underwent ultrasound (U/S) examination in the Department of Obstetrics and Gynecology with isolated RPD of $4 mm at < 33 wks or $7 mm at >33 wks and known postnatal follow-up at St. Louis Children’s Hospital. All cases had postnatal U/S and evaluation by Ped Urology. RESULTS: Postnatal diagnoses included nonobstructive hydronephrosis (NOH) (40%), ureteropelvic junction obstruction (UPJO) (19%), megaureter (9%), reflux (7%), multicystic dysplastic kidney (7%), ureterocele (7%), normal (NL) (5%), and other (7%). One-way ANOVA indicated no difference in fetuses with normal postnatal ultrasound and those with NOH, defined as RPD that resolved or did not progress and did not require surgery. Receiver operating characteristic (ROC) analysis was performed comparing the maximum RPD in the NL/NOH (n = 128) group and the UPJO group (n = 53). ROC analysis revealed that the renal pelvis diameter that correctly classified the highest percentage (85%) of fetuses with respect to obstructive or nonobstructive postnatal hydronephrosis was 17 mm, with a sensitivity of 70% and specificity of 91%. Area under the ROC curve equals 0.859 with a standard error of 0.032 and a 95% confidence interval of 0.795 to 0.923. CONCLUSION: The current threshold for fetal pathologic RPD utilized at this institution was devised to ensure 100% sensitivity with less regard for specificity. When fetal RPD is associated with 100% sensitivity for detection of postnatal obstructive hydronephrosis, the false-positive rate is >90%. If maximum sensitivity is desired, consideration should be given to a single postnatal U/S rather than serial prenatal U/Ss in cases of mild ( < 10 mm) RPD.
673
NUCHAL TRANSLUCENCY MEASUREMENTS FOR DETERMINATION OF FETAL SELECTION IN MULTIFETAL PREGNANCY REDUCTION JULIE MOLDENHAUER1, ADEL GILBERT1, PATRICIA DEVERS1, KRISTEN MCBRIDE1, MARJORIE TREADWELL1, ANTHONY JOHNSON1, 1Wayne State University, Obstetrics and Gynecology, Detroit, MI OBJECTIVE: To investigate the practicality of utilizing non-invasive nuchal translucency (NT) measurements for fetal selection in gestations undergoing multifetal pregnancy reduction (MFPR). STUDY DESIGN: A retrospective review of patients presenting to our unit from December 1, 2000, until July 31, 2003, for the purpose of MFPR who declined concomitant invasive prenatal diagnosis. RESULTS: 77 patients with 276 live fetuses presented for MFPR. Gestational ages ranged from 9.5 to 14.1 weeks. The starting and finishing number of fetuses ranged from 2-8 and 1-3, respectively. NT measurements were able to be obtained in 211 of 276 (76.4%). Six measured $3 mm and 14 had NT measurements $2 mm but were < 3 mm. A total of 134 fetuses were reduced in the study group. Of the reduced fetuses, 4.5% (6/134) had an NT $3 mm, and 11.9% (16/134) had an NT $2 mm. Seven pregnancies with 13 fetuses are lost to follow-up and 23 pregnancies with 40 fetuses are ongoing at the time of abstract submission. In the delivered cohort of 47 pregnancies with 89 fetuses there was 1 triplet pregnancy that was further reduced to twins after later detection of a cardiac anomaly, a spontaneous abortion of a twin pregnancy, 4 twin pregnancies with a fetal demise of a co-twin who each then delivered a normal single liveborn, giving total pregnancy and fetal loss rates of 2.1% (1/47) and 6.8% (6/88), respectively. CONCLUSION: NT measurements were obtained in 76.4% of all fetuses and are a viable non-invasive method to assist in the selection of fetal reduction in MFPR procedures. NT measurements should be a routine part of screening for patients undergoing MFPR.
672
ETHNIC VARIATIONS IN THE PREVALENCE OF ECHOGENIC INTRACARDIAC FOCI SUSAN H. TRAN1, AARON B. CAUGHEY2, MARY E. NORTON2, 1Kaiser Permanente Medical Center, Obstetrics and Gynecology, San Francisco, CA 2University of California, San Francisco, Obstetrics, Gynecology and Repro. Sciences, San Francisco, CA OBJECTIVE: To determine whether the prevalence of echogenic intracardiac foci (EIF) is affected by maternal ethnicity. STUDY DESIGN: A retrospective cohort study of all women undergoing second-trimester diagnostic ultrasound examination at a prenatal diagnosis referral center from January 1, 2000, to July 1, 2003. Data were collected on the frequency of echogenic intracardiac foci, gestational age at time of ultrasound, and maternal age and ethnicity. Univariate and multivariate analyses were conducted using STATA software. RESULTS: Among the 7535 women who underwent ultrasound examination for prenatal diagnosis during the study period, EIF was found in 309 (4.1%). When maternal ethnicity was subdivided into Caucasian, African American, Hispanic, Asian, Native American, Filipino, East Indian, and Middle Eastern, the highest rates of EIF were found in fetuses of Middle Eastern (8.1%), Asian (7.6%), and African American (6.7%) mothers compared to a rate of 3.3% in Caucasians (P < 0.001). In multivariate analyses controlling for maternal age greater than or equal to 35 years, the odds ratio for the presence of EIF was 2.5 (95% CI, 1.80, 3.40) in Asians and 1.9 (95% CI, 1.21, 2.96) in African Americans as compared to Caucasians. Despite the variation in EIF prevalence, it was associated with an increased risk (OR range from 1.9 to 7.0) for Down syndrome. CONCLUSION: Middle Eastern, Asian, and African American patients are more likely than patients of other ethnicities to have a fetus with EIF. This should be considered in the counseling of such patients. As more data accumulate, ethnic-based odds ratios may be used to adjust the a priori risk of Down syndrome.
674
THE UTILITY OF MRI IN ULTRASOUND-DETECTED FETAL CNS ABNORMALITIES JULIE MOLDENHAUER1, BETSY BEYER1, SWATI MODY2, APARNA JOSHI2, ANTHONY JOHNSON1, MARJORIE TREADWELL1, 1Wayne State University, Obstetrics and Gynecology, Detroit, MI 2 Wayne State University, Pediatric Radiology, Detroit, MI OBJECTIVE: The purpose of this study was to investigate the utility of magnetic resonance imagining (MRI) as an adjunct to 2-dimensional ultrasound (US) in the evaluation of suspected fetal central nervous system (CNS) malformations. STUDY DESIGN: A retrospective review of consecutive cases of patients with suspected fetal CNS malformations by US and MRI seen during the past 3 years in a tertiary care ultrasound unit. RESULTS: 18 patients with sonographically suspected CNS malformations underwent antenatal MRI. The average gestational age at the time of ultrasound and MRI was 24.1 weeks (range 19-34) and 26.9 weeks (range 20-35). The average time interval between ultrasound and MRI was 2.8 weeks (range 0-11). US and MRI were concordant in 16 of 18 (89%) cases. Additional information was gained by use of MRI in 5 patients. Two non-concordant cases included one failed MRI due to fetal motion and an encephalocele by US where MRI suggested calvarial deformity without defect. Neonatal evaluation was available in 12 cases. In the 11 concordant cases with neonatal outcomes, antenatal findings were confirmed in 9 of 11. In the case with discordance between U/S and MRI, prenatal diagnosis of encephalocele was confirmed postnatally. The two unconfirmed concordant cases were partial agenesis of the cerebellar vermis: one normal appearing neonate did not undergo postnatal imaging, and the other had a postnatal US, which described a normal posterior fossa. Massive autolysis prevented evaluation in one stillbirth; an additional case is ongoing; outcomes are not available in four cases. CONCLUSION: Subsequent imaging with MRI can confirm and provide additional information after antenatal US diagnosis of CNS malformations. This information can solidify the prenatal diagnosis. The usefulness may relate to the certainty of, or the specific prenatal diagnosis. The utility of additional imaging techniques, such as MRI and 3D ultrasound, in the diagnosis of fetal CNS abnormalities needs to be better defined.
Volume 189, Number 6 Am J Obstet Gynecol 671
THE UTILITY OF FETAL RENAL PELVIS DILATION IN DISTINGUISHING BETWEEN OBSTRUCTIVE AND NONOBSTRUCTIVE POSTNATAL HYDRONEPHROSIS JEFFREY M. DICKE1, DOUGLAS COPLEN1, 1Washington University in St. Louis, Obstetrics & Gynecology, St. Louis, MO OBJECTIVE: To determine the efficacy of current thresholds for fetal renal pelvis dilation (RPD) in identifying significant postnatal urinary tract obstruction. STUDY DESIGN: A retrospective analysis of prospectively collected measurements of fetal RPD. The entire study population consists of 287 fetuses who underwent ultrasound (U/S) examination in the Department of Obstetrics and Gynecology with isolated RPD of $4 mm at < 33 wks or $7 mm at >33 wks and known postnatal follow-up at St. Louis Children’s Hospital. All cases had postnatal U/S and evaluation by Ped Urology. RESULTS: Postnatal diagnoses included nonobstructive hydronephrosis (NOH) (40%), ureteropelvic junction obstruction (UPJO) (19%), megaureter (9%), reflux (7%), multicystic dysplastic kidney (7%), ureterocele (7%), normal (NL) (5%), and other (7%). One-way ANOVA indicated no difference in fetuses with normal postnatal ultrasound and those with NOH, defined as RPD that resolved or did not progress and did not require surgery. Receiver operating characteristic (ROC) analysis was performed comparing the maximum RPD in the NL/NOH (n = 128) group and the UPJO group (n = 53). ROC analysis revealed that the renal pelvis diameter that correctly classified the highest percentage (85%) of fetuses with respect to obstructive or nonobstructive postnatal hydronephrosis was 17 mm, with a sensitivity of 70% and specificity of 91%. Area under the ROC curve equals 0.859 with a standard error of 0.032 and a 95% confidence interval of 0.795 to 0.923. CONCLUSION: The current threshold for fetal pathologic RPD utilized at this institution was devised to ensure 100% sensitivity with less regard for specificity. When fetal RPD is associated with 100% sensitivity for detection of postnatal obstructive hydronephrosis, the false-positive rate is >90%. If maximum sensitivity is desired, consideration should be given to a single postnatal U/S rather than serial prenatal U/Ss in cases of mild ( < 10 mm) RPD.
673
NUCHAL TRANSLUCENCY MEASUREMENTS FOR DETERMINATION OF FETAL SELECTION IN MULTIFETAL PREGNANCY REDUCTION JULIE MOLDENHAUER1, ADEL GILBERT1, PATRICIA DEVERS1, KRISTEN MCBRIDE1, MARJORIE TREADWELL1, ANTHONY JOHNSON1, 1Wayne State University, Obstetrics and Gynecology, Detroit, MI OBJECTIVE: To investigate the practicality of utilizing non-invasive nuchal translucency (NT) measurements for fetal selection in gestations undergoing multifetal pregnancy reduction (MFPR). STUDY DESIGN: A retrospective review of patients presenting to our unit from December 1, 2000, until July 31, 2003, for the purpose of MFPR who declined concomitant invasive prenatal diagnosis. RESULTS: 77 patients with 276 live fetuses presented for MFPR. Gestational ages ranged from 9.5 to 14.1 weeks. The starting and finishing number of fetuses ranged from 2-8 and 1-3, respectively. NT measurements were able to be obtained in 211 of 276 (76.4%). Six measured $3 mm and 14 had NT measurements $2 mm but were < 3 mm. A total of 134 fetuses were reduced in the study group. Of the reduced fetuses, 4.5% (6/134) had an NT $3 mm, and 11.9% (16/134) had an NT $2 mm. Seven pregnancies with 13 fetuses are lost to follow-up and 23 pregnancies with 40 fetuses are ongoing at the time of abstract submission. In the delivered cohort of 47 pregnancies with 89 fetuses there was 1 triplet pregnancy that was further reduced to twins after later detection of a cardiac anomaly, a spontaneous abortion of a twin pregnancy, 4 twin pregnancies with a fetal demise of a co-twin who each then delivered a normal single liveborn, giving total pregnancy and fetal loss rates of 2.1% (1/47) and 6.8% (6/88), respectively. CONCLUSION: NT measurements were obtained in 76.4% of all fetuses and are a viable non-invasive method to assist in the selection of fetal reduction in MFPR procedures. NT measurements should be a routine part of screening for patients undergoing MFPR.
672
ETHNIC VARIATIONS IN THE PREVALENCE OF ECHOGENIC INTRACARDIAC FOCI SUSAN H. TRAN1, AARON B. CAUGHEY2, MARY E. NORTON2, 1Kaiser Permanente Medical Center, Obstetrics and Gynecology, San Francisco, CA 2University of California, San Francisco, Obstetrics, Gynecology and Repro. Sciences, San Francisco, CA OBJECTIVE: To determine whether the prevalence of echogenic intracardiac foci (EIF) is affected by maternal ethnicity. STUDY DESIGN: A retrospective cohort study of all women undergoing second-trimester diagnostic ultrasound examination at a prenatal diagnosis referral center from January 1, 2000, to July 1, 2003. Data were collected on the frequency of echogenic intracardiac foci, gestational age at time of ultrasound, and maternal age and ethnicity. Univariate and multivariate analyses were conducted using STATA software. RESULTS: Among the 7535 women who underwent ultrasound examination for prenatal diagnosis during the study period, EIF was found in 309 (4.1%). When maternal ethnicity was subdivided into Caucasian, African American, Hispanic, Asian, Native American, Filipino, East Indian, and Middle Eastern, the highest rates of EIF were found in fetuses of Middle Eastern (8.1%), Asian (7.6%), and African American (6.7%) mothers compared to a rate of 3.3% in Caucasians (P < 0.001). In multivariate analyses controlling for maternal age greater than or equal to 35 years, the odds ratio for the presence of EIF was 2.5 (95% CI, 1.80, 3.40) in Asians and 1.9 (95% CI, 1.21, 2.96) in African Americans as compared to Caucasians. Despite the variation in EIF prevalence, it was associated with an increased risk (OR range from 1.9 to 7.0) for Down syndrome. CONCLUSION: Middle Eastern, Asian, and African American patients are more likely than patients of other ethnicities to have a fetus with EIF. This should be considered in the counseling of such patients. As more data accumulate, ethnic-based odds ratios may be used to adjust the a priori risk of Down syndrome.
674
THE UTILITY OF MRI IN ULTRASOUND-DETECTED FETAL CNS ABNORMALITIES JULIE MOLDENHAUER1, BETSY BEYER1, SWATI MODY2, APARNA JOSHI2, ANTHONY JOHNSON1, MARJORIE TREADWELL1, 1Wayne State University, Obstetrics and Gynecology, Detroit, MI 2 Wayne State University, Pediatric Radiology, Detroit, MI OBJECTIVE: The purpose of this study was to investigate the utility of magnetic resonance imagining (MRI) as an adjunct to 2-dimensional ultrasound (US) in the evaluation of suspected fetal central nervous system (CNS) malformations. STUDY DESIGN: A retrospective review of consecutive cases of patients with suspected fetal CNS malformations by US and MRI seen during the past 3 years in a tertiary care ultrasound unit. RESULTS: 18 patients with sonographically suspected CNS malformations underwent antenatal MRI. The average gestational age at the time of ultrasound and MRI was 24.1 weeks (range 19-34) and 26.9 weeks (range 20-35). The average time interval between ultrasound and MRI was 2.8 weeks (range 0-11). US and MRI were concordant in 16 of 18 (89%) cases. Additional information was gained by use of MRI in 5 patients. Two non-concordant cases included one failed MRI due to fetal motion and an encephalocele by US where MRI suggested calvarial deformity without defect. Neonatal evaluation was available in 12 cases. In the 11 concordant cases with neonatal outcomes, antenatal findings were confirmed in 9 of 11. In the case with discordance between U/S and MRI, prenatal diagnosis of encephalocele was confirmed postnatally. The two unconfirmed concordant cases were partial agenesis of the cerebellar vermis: one normal appearing neonate did not undergo postnatal imaging, and the other had a postnatal US, which described a normal posterior fossa. Massive autolysis prevented evaluation in one stillbirth; an additional case is ongoing; outcomes are not available in four cases. CONCLUSION: Subsequent imaging with MRI can confirm and provide additional information after antenatal US diagnosis of CNS malformations. This information can solidify the prenatal diagnosis. The usefulness may relate to the certainty of, or the specific prenatal diagnosis. The utility of additional imaging techniques, such as MRI and 3D ultrasound, in the diagnosis of fetal CNS abnormalities needs to be better defined.