Study Type
Study Type
Study Objective(Purpose of Study)
Study Objective(Purpose of Study)
Study Results
Study Results
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Study Quality
1. Copel JA, Bahtiyar MO. A practical approach to fetal growth restriction. Obstet Gynecol. 2014;123(5):1057-1069. Review/Other-Tx N/A To offer a practical approach to management and timing of delivery based on available data in the literature. No results stated in abstract. 4
2. Figueras F, Gratacos E. An integrated approach to fetal growth restriction. Best Pract Res Clin Obstet Gynaecol. 2017;38:48-58. Review/Other-Tx N/A To propose that the management of Fetal growth restriction (FGR) can be simplified using a sequential approach based on three steps: (1) identification of the "small fetus," (2) differentiation between FGR and small for gestational age (SGA), and (3) timing of delivery according to a protocol based on stages of fetal deterioration. No results stated in abstract. 4
3. Ott WJ. Intrauterine growth restriction and Doppler ultrasonography. J Ultrasound Med. 2000;19(10):661-665; quiz 667. Observational-Dx 578 patients A retrospective study to clarify the difference between the fetus that is small for gestational age and the fetus with true intrauterine growth restriction. The small for gestational age fetuses with normal Doppler studies showed no increased morbidity when compared with their average for gestational age cohorts. Umbilical artery Doppler blood flow studies were a better predictor of neonatal outcome than estimated fetal weight. Small for gestational age fetuses with normal Doppler studies most likely represent constitutionally small, not pathologically growth restricted, fetuses. 4
4. Savchev S, Sanz-Cortes M, Cruz-Martinez R, et al. Neurodevelopmental outcome of full-term small-for-gestational-age infants with normal placental function. Ultrasound Obstet Gynecol. 2013;42(2):201-206. Observational-Dx 223 infants To evaluate the 2-year neurodevelopmental outcome of full-term, small-for-gestational-age (SGA) newborns with normal placental function, according to current criteria based on umbilical artery Doppler findings. All studied neurodevelopmental domains were poorer in the SGA group, reaching significance for the cognitive (92.9 vs 100.2, adjusted P = 0.027), language (94.7 vs 101, adjusted P = 0.025), motor (94.2 vs 100, adjusted P = 0.027) and adaptive (89.2 vs 96.5, adjusted P = 0.012) scores. Likewise, the SGA group had a higher risk of low scores in language (odds ratio (OR) = 2.63; adjusted P = 0.045) and adaptive (OR = 2.72; adjusted P = 0.009) domains. 4
5. Morales-Rosello J, Khalil A, Morlando M, Papageorghiou A, Bhide A, Thilaganathan B. Changes in fetal Doppler indices as a marker of failure to reach growth potential at term. Ultrasound Obstet Gynecol. 2014;43(3):303-310. Observational-Dx 11576 term fetuses To evaluate whether changes in the middle cerebral artery (MCA), umbilical artery (UA) and cerebroplacental ratio (CPR) Doppler indices at term might be used to identify those appropriate-for-gestational-age (AGA) fetuses that are failing to reach their growth potential (FRGP). Within the AGA group, fetuses with lower birth weight (BW) had significantly higher UA pulsatility index (PI), lower MCA-PI and lower CPR MoM values. Large-for-gestational-age (LGA) fetuses were considered as the group least likely to be growth-restricted. The CPR multiples of the median (MoM) < 5(th) centile (0.6765 MoM) in these fetuses was used as a threshold for diagnosing FRGP. Using this definition, in the AGA pregnancies the percentage of fetuses with FRGP was 1% in the 75-90(th) BW centile group, 1.7% in the 50-75(th) centile group, 2.9% in the 25-50(th) centile group and 6.7% in the 10-25(th) centile group. 4
6. Prior T, Paramasivam G, Bennett P, Kumar S. Are fetuses that fail to achieve their growth potential at increased risk of intrapartum compromise? Ultrasound Obstet Gynecol. 2015;46(4):460-464. Observational-Dx 775 women To apply a new definition using cerebroplacental ratio (CPR) <0.6765 multiples of the median to a cohort of low-risk pregnancies recruited prospectively to determine if fetuses with CPR < 0.6765 are at increased risk of developing signs of intrapartum fetal compromise. Fetuses with CPR < 0.6765 MoM were significantly more likely to require Cesarean delivery because of presumed fetal compromise (P < 0.001). These fetuses were also at increased risk of compromise at any time during labor and were less likely to be delivered vaginally, spontaneously or otherwise, than were those with CPR >/= 0.6765 MoM. CPR < 0.6765 MoM gave a positive predictive value (PPV) for Cesarean delivery because of presumed fetal compromise of 36.7% and a negative predictive value of 88.7%, with a sensitivity of 18% and a specificity of 95.4%. 3
7. A randomised trial of timed delivery for the compromised preterm fetus: short term outcomes and Bayesian interpretation. Bjog. 2003;110(1):27-32. Experimental-Dx 547 mothers; 587 babies To compare the effect of delivering early to pre-empt terminal hypoxaemia with delaying for as long as possible to increase maturity. Of 548 women (588 babies) recruited, outcomes were available on 547 mothers (587 babies). The median time-to-delivery intervals were 0.9 days in the immediate group and 4.9 days in the delay group. Total deaths prior to discharge were 29 (10%) in the immediate group versus 27 (9%) in the delay group (odds ratio 1.1, 95% CI 0.61-1.8). Total caesarean sections were 249 (91%) in the immediate group versus 217 (79%) in the delay group: (OR 2.7; 95% CI 1.6-4.5). These odds ratios were similar for those randomized at gestational ages above or below 30 weeks. 1
8. Figueras F, Gratacos E. Stage-based approach to the management of fetal growth restriction. Prenat Diagn. 2014;34(7):655-659. Review/Other-Dx N/A To propose a protocol that integrates current evidence to classify stages of fetal deterioration, and establishes follow-up intervals and optimal delivery timings, which may facilitate decision-making and minimize variability in the clinical management. No results stated in abstract. 4
9. Thornton JG, Hornbuckle J, Vail A, Spiegelhalter DJ, Levene M. Infant wellbeing at 2 years of age in the Growth Restriction Intervention Trial (GRIT): multicentred randomised controlled trial. Lancet. 2004;364(9433):513-520. Experimental-Dx 548 pregnant women To compare the effect of delivering early with delaying birth among pregnant women. Primary outcomes were available on 290 (98%) immediate and 283 (97%) deferred deliveries. Overall rate of death or severe disability at 2 years was 55 (19%) of 290 immediate births, and 44 (16%) of 283 delayed births. With adjustment for gestational age and umbilical-artery doppler category, the odds ratio (95% CrI) was 1.1 (0.7-1.8). Most of the observed difference was in disability in babies younger than 31 weeks of gestation at randomisation: 14 (13%) immediate versus five (5%) delayed deliveries. No important differences in the median Griffiths developmental quotient in survivors was seen. 1
10. Scala C, Bhide A, Familiari A, et al. Number of episodes of reduced fetal movement at term: association with adverse perinatal outcome. Am J Obstet Gynecol. 2015;213(5):678 e671-676. Observational-Dx 21944 women To evaluate the association of reduced fetal movements (RFM) and small-for-gestational-age (SGA) birth at term and to explore if fetal and maternal outcomes are different with single vs repeated episodes of RFM and normal fetal assessment test results. Of the 21,944 women with a singleton pregnancy booked for maternity care during the study period, 1234 women (5.62%) reported RFMs >36+0 weeks. Of these, 1029 women (83.4%) reported a single episode of RFM and 205 (16.6%) had >/=2 presentations for RFM. Women with repeated RFMs had a significantly higher mean uterine artery pulsatility index in the second trimester. The prevalence of SGA baby at birth in women presenting with a single episode as compared to repeated episodes of RFM was 9.8% and 44.2%, respectively (odds ratio, 7.3; 95% confidence interval, 5.1-10.4; P < .05). 3
11. ACOG Practice bulletin no. 134: fetal growth restriction. Obstet Gynecol. 2013;121(5):1122-1133. Review/Other-Dx N/A To review the topic of fetal growth restriction with a focus on terminology, etiology, diagnostic and surveillance tools, and guidance for management and timing of delivery. No results stated in abstract. 4
12. Morales Rosello J, Hervas Marin D, Perales Marin A, Lopez Fraile S. Doppler study of the fetal vertebral and middle cerebral arteries in fetuses with normal and increased umbilical artery resistance indices. J Clin Ultrasound. 2013;41(4):224-229. Observational-Dx 1084 doppler examinations;1084 fetuses To compare the brain sparing mechanism of the fetal vertebral artery (VA), with the one of the middle cerebral artery (MCA) in fetuses with increased umbilical artery (UA) Doppler impedance. For both, the VA  resistance index (RI) and MCA RI, no differences were seen among the groups of fetuses who maintained diastolic flow in the UA. However, the VA RI and MCA RI were lower when the UA diastolic flow was absent. 3
13. Flood K, Unterscheider J, Daly S, et al. The role of brain sparing in the prediction of adverse outcomes in intrauterine growth restriction: results of the multicenter PORTO Study. Am J Obstet Gynecol. 2014;211(3):288 e281-285. Observational-Dx 1100 singleton pregnancies To evaluate the optimal management of fetuses with an estimated fetal weight less than the 10th centile and to describe the role of the cerebroplacental ratio (CPR) in the prediction of adverse perinatal outcome. Data for CPR calculation was available in 881 cases, which was performed at a mean gestational age of 33 weeks (interquarile range, 28.7-35.9). Of the 146 cases with CPR less than 1, 18% (n = 27) had an adverse perinatal outcome. This conferred an 11-fold increased risk (odds ratio, 11.7; P < .0001) when compared with cases with normal CPR (2%; 14 of 735). An abnormal CPR was present in all 3 cases of mortality. Prediction of adverse outcomes was comparable when using all definitions of abnormal CPR. 2
14. Spinillo A, Gardella B, Bariselli S, Alfei A, Silini EM, Bello BD. Cerebroplacental Doppler ratio and placental histopathological features in pregnancies complicated by fetal growth restriction. J Perinat Med. 2014;42(3):321-328. Observational-Dx 176 singleton pregnancies To correlate placental pathologic lesions, as defined by the Society for Pediatric Pathology, to the severity of the ratio of the pulsatility Doppler index (PI) of the fetal middle cerebral artery to that of the umbilical artery (cerebroplacental ratio, CPR). The mean values of gestational age, birth weight and CPR of the entire cohort were 33.9+/-3.6 weeks, 1552+/-561 g, and 1.33+/-0.68, respectively. In ordered logistic regression analysis, after adjustment for potential confounders, muscularised arteries (Odds Ratio [OR]=3.14; 95% confidence intervals [CI]=1.58-6.28, P=0.001), mural hypertrophy (OR=2.35; 95% CI=1.26-4.4, P=0.008), immature intermediate trophoblast (OR=2.0; 95% CI=1.07-3.71, P=0.03) and maternal vascular underperfusion (OR=2.32; 95% CI=1.25-4.23, P=0.007) were the only parameters associated with severity of CPR. 4
15. DeVore GR. The importance of the cerebroplacental ratio in the evaluation of fetal well-being in SGA and AGA fetuses. Am J Obstet Gynecol. 2015;213(1):5-15. Review/Other-Dx 8 studies To review the data from studies in which cerebroplacental ratio (CPR) has been evaluated in fetuses that were appropriate for gestational age (AGA) and those with SGA (small for gestational age) to determine whether this test should be considered for integration into clinical practice. Fetuses with an abnormal CPR that are appropriate for gestational age or have late-onset SGA (>34 weeks of gestation) have a higher incidence of fetal distress in labor requiring emergency cesarean delivery, a lower cord pH, and an increased admission rate to the newborn intensive care unit when compared with fetuses with a normal CPR. Fetuses with early-onset SGA (<34 weeks of gestation) with an abnormal CPR have a higher incidence of the following when compared with fetuses with a normal CPR: (1) lower gestational age at birth, (2) lower mean birthweight, (3) lower birthweight centile, (4) birthweight less than the 10th centile, (5) higher rate of cesarean delivery for fetal distress in labor, (6) higher rate of Apgar scores less than 7 at 5 minutes, (7) an increased rate of neonatal acidosis, (8) an increased rate of newborn intensive care unit admissions, (9) higher rate of adverse neonatal outcome, and (10) a greater incidence of perinatal death. The CPR is also an earlier predictor of adverse outcome than the biophysical profile, umbilical artery, or middle cerebral artery. 4
16. Warshak CR, Masters H, Regan J, DeFranco E. Doppler for growth restriction: the association between the cerebroplacental ratio and a reduced interval to delivery. J Perinatol. 2015;35(5):332-337. Observational-Dx 154 patients To evaluate the cerebroplacental ratio (CPR) as an adjunct to umbilical artery Doppler (UA) to assess risk of delivery before 32 weeks and/or delivery within 2 weeks from diagnosis of fetal growth restriction (FGR). Subjects in Group 3 had higher rates of the two primary outcomes: there was a fivefold increased risk (Adjusted odds ratio (aOR) =5.2 (95% CI=2.85-9.48)) for delivery before 32 weeks and over a fourfold increased risk for delivery within 2 weeks (aOR=4.76 (95% CI=2.32-9.76)) compared with those with a normal CPR (Group 1). In contrast, subjects in Group 2 (abnormal UA Doppler but normal CPR) had a similar rate of delivery before 32 weeks (aOR=1.16 (95% CI=0.55-2.48)) and within 2 weeks (aOR=1.07 (95% confidence interval (CI)=0.43-2.69)). The median gestational age at delivery was 36, 36 and 29 weeks in Groups 1, 2 and 3, respectively (P<0.001). Linear regression analysis revealed a strong correlation between the value of the CPR and gestational age at delivery: R(2)=0.56, correlation coefficient=0.75. Kaplan-Meier analysis revealed a significantly decreased latency to delivery in Group 3, as opposed to Groups 1 and 2 (Cox-Mantel hazard ratio (HR) of Group 2 versus Group 1 HR=1.20 (95% CI=0.78-1.83) and Group 3 versus Group 1 HR=5.00 (95% CI=2.4-10.21)). 3
17. Dunn L, Sherrell H, Kumar S. Review: Systematic review of the utility of the fetal cerebroplacental ratio measured at term for the prediction of adverse perinatal outcome. Placenta. 2017;54:68-75. Review/Other-Dx N/A To evaluate the utility of the fetal cerebroplacental ratio (CPR) when assessed at term (from 37 + 0 weeks gestation) as a predictor of adverse obstetric and perinatal outcomes. Fetal CPR was predictive of caesarean section for intrapartum fetal compromise, small for gestational age and fetal growth restriction and neonatal intensive care unit admission. Low CPR was also significantly associated with abnormal fetal heart rate pattern, meconium stained liquor, low Apgar score, acidosis at birth and composite adverse perinatal outcome scores. The CPR when taken at term had comparable if not better predictive value than that when taken at preterm. Most studies included small for gestational age fetuses and postdate pregnancies. Subtle variation existed in the threshold for low CPR. 4
18. Cosmi E, Ambrosini G, D'Antona D, Saccardi C, Mari G. Doppler, cardiotocography, and biophysical profile changes in growth-restricted fetuses. Obstet Gynecol. 2005;106(6):1240-1245. Observational-Dx 145 singleton growth-restricted fetuses To assess from diagnosis to delivery the Doppler studies of the umbilical artery, middle cerebral artery, umbilical vein, ductus venosus, and amniotic fluid index of fetuses with idiopathic growth restriction. There were 4 fetal and 50 neonatal deaths. Two growth-restricted groups were identified: Group A (n = 44) included fetuses in whom all measures became abnormal preceding an abnormal biophysical profile or nonreassuring nonstress test. Group B (n = 101) included fetuses in whom 1 or more measures were normal at the time of cesarean delivery. There was no statistically significant difference in perinatal morbidity and mortality between the 2 groups. Neonatal death was increased in fetuses with umbilical artery reversed flow (odds ratio 2.34, 95% confidence interval 1.16-4.73; P < .05) and ductus venosus reversed flow (odds ratio 4.18, 95% confidence interval 2.01-8.69; P < .05). A significant correlation was also found between low birth weight and adverse perinatal outcome. 3
19. Baschat AA, Cosmi E, Bilardo CM, et al. Predictors of neonatal outcome in early-onset placental dysfunction. Obstet Gynecol. 2007;109(2 Pt 1):253-261. Observational-Dx 604 patients To identify specific estimates and predictors of neonatal morbidity and mortality in early onset fetal growth restriction due to placental dysfunction. Major morbidity occurred in 35.9% of 604 neonates: bronchopulmonary dysplasia in 23.2% (n=140), intraventricular hemorrhage in 15.2% (n=92), and necrotizing enterocolitis in 12.4% (n=75). Total mortality was 21.5 % (n=130), and 58.3% survived without complication (n=352). From 24 to 32 weeks, major morbidity declined (56.6% to 10.5%), coinciding with survival that exceeded 50% after 26 weeks. Gestational age was the most significant determinant (P<.005) of total survival until 26(6/7) weeks (r(2)=0.27), and intact survival until 29(2/7) weeks (r(2)=0.42). Beyond these gestational-age cutoffs, and above birth weight of 600 g, ductus venosus Doppler and cord artery pH predicted neonatal mortality (P<.001, r(2)=0.38), and ductus venosus Doppler alone predicted intact survival (P<.001, r(2)=0.34). 3
20. Hassan WA, Brockelsby J, Alberry M, Fanelli T, Wladimiroff J, Lees CC. Cardiac function in early onset small for gestational age and growth restricted fetuses. Eur J Obstet Gynecol Reprod Biol. 2013;171(2):262-265. Observational-Dx 48 cases; 11 small for gestational age & 12 intrauterine growth restricted To examine cardiac function in appropriately grown, small for gestational age and intrauterine growth restricted fetuses and investigate the relationship between cardiac function and fetal arterial and venous Doppler parameters. In small for gestational age fetuses and fetuses with intrauterine growth restriction the myocardial performance index was 0.66 (0.63-0.7) and 0.64 (0.60-0.67), respectively, and compared to appropriately grown fetuses, at 0.45 (0.43-0.47), was significantly increased (p=0.001). No relationship was found between the myocardial performance index and arterial and venous Doppler Z-score. 3
21. Gudmundsson S, Flo K, Ghosh G, Wilsgaard T, Acharya G. Placental pulsatility index: a new, more sensitive parameter for predicting adverse outcome in pregnancies suspected of fetal growth restriction. Acta Obstet Gynecol Scand. 2017;96(2):216-222. Observational-Dx 53 pregnancies To combine the pulsatility indices of the umbilical and uterine arteries as the surrogate measures of utero-placental perfusion. The placental pulsatility index was closely associated with gestational age and decreased with advancing gestation in normal pregnancy. The placental pulsatility index had a higher sensitivity and comparable specificity in predicting adverse outcome in pregnancies suspected of intra-uterine fetal growth restriction when compared with conventional umbilical and uterine artery pulsatility indices. 3
22. Snijders RJ, Sherrod C, Gosden CM, Nicolaides KH. Fetal growth retardation: associated malformations and chromosomal abnormalities. Am J Obstet Gynecol. 1993;168(2):547-555 Review/Other-Dx 458 fetuses To determine the incidence and pattern of chromosomal abnormalities in fetal growth retardation. The fetal karyotype was normal in 369 and abnormal in 89 (19%) of the cases. The most common chromosomal defect in the group referred at < 26 weeks' gestation was triploidy; in those referred at > or = 26 weeks, it was trisomy 18. The incidence of fetal autosomal chromosome aberrations increased, whereas the incidence of triploidy did not change, with maternal age. Ninety-six percent of chromosomally abnormal fetuses had multisystem fetal defects that were characteristic of the different types of chromosomal abnormalities. Compared with those fetuses with a normal karyotype, the chromosomally abnormal group had a higher mean head circumference/abdominal circumference ratio, a higher incidence of normal or increased amniotic fluid volume, and normal waveforms from the uterine or umbilical arteries or both. 4
23. Contro E, Cha DH, De Maggio I, et al. Uterine artery Doppler longitudinal changes in pregnancies complicated with intrauterine growth restriction without preeclampsia. Prenat Diagn. 2014;34(13):1332-1336. Observational-Dx 53 cases; 1000 controls To evaluate the longitudinal changes in uterine artery Doppler pulsatility index (UtA-PI) in pregnancies complicated with early onset intrauterine growth restriction (IUGR). Regression line having log10 UtA-PI as dependent variable was a function of both gestational age and IUGR. UtA-PI decreased with gestational age in both groups. In IUGR group, UtA-PI was higher from 20 weeks onward and the difference with controls increased with gestational age. In fact, at 20 weeks, the UtA-PI ratio between cases and controls was 1.84, but at 30 weeks it rose to 2.05. Finally, the weight at delivery in the IUGR group was also inversely correlated with the UtA-PI values. 4
24. Savchev S, Figueras F, Sanz-Cortes M, et al. Evaluation of an optimal gestational age cut-off for the definition of early- and late-onset fetal growth restriction. Fetal Diagn Ther. 2014;36(2):99-105. Observational-Dx 656 pregnant women To distinguish two phenotypes characterized by differences in onset, fetoplacental Doppler, association with preeclampsia (PE) and severity. We evaluated the optimal gestational age (GA) cut-off maximizing differences among these two forms. We identified 32 weeks at diagnosis as the optimal cut-off, resulting in two groups with 7.1 and 0%, p < 0.001 perinatal mortality, 35.1 and 12.1%, p < 0.001 association with PE, and 13.4 and 4.6%, p < 0.001 composite adverse perinatal outcome. Abnormal versus normal umbilical artery (UA) Doppler classified two groups with 10.6 and 0.2%, p < 0.001 perinatal mortality, 50.0 and 11.8%, p < 0.001 association with PE, and 18.2 and 4.2%, p < 0.001 composite adverse perinatal outcome. 3
25. Crimmins S, Desai A, Block-Abraham D, Berg C, Gembruch U, Baschat AA. A comparison of Doppler and biophysical findings between liveborn and stillborn growth-restricted fetuses. Am J Obstet Gynecol. 2014;211(6):669 e661-610. Observational-Dx 987 patients To evaluate the surveillance characteristics that precede stillbirth in growth-restricted fetuses that receive integrated Doppler and biophysical profile scoring (BPS). Forty-seven stillbirths occurred in 2 clusters, 37 at <34 weeks of gestation and 10 thereafter. Before 34 weeks of gestation, stillbirths had parallel escalation of umbilical artery and ductus venosus Doppler findings followed by abnormal biophysical profile scoring (BPS). At >/=34 weeks of gestation, only a decline in middle cerebral artery (MCA) pulsatility index was observed, and 75% of stillbirths were unanticipated by the BPS. 3
26. Roma E, Arnau A, Berdala R, Bergos C, Montesinos J, Figueras F. Ultrasound screening for fetal growth restriction at 36 vs 32 weeks' gestation: a randomized trial (ROUTE). Ultrasound Obstet Gynecol. 2015;46(4):391-397. Observational-Dx 2586 patients To compare the utility of routine third-trimester ultrasound examination at 36 weeks' gestation with that at 32 weeks in detecting fetal growth restriction (FGR). There were no significant differences in perinatal outcome between those who underwent a scan at 32 weeks' gestation and those who underwent a scan at 36 weeks' gestation. Severe FGR at birth was associated significantly with emergency Cesarean delivery for fetal distress (odds ratio (OR), 3.4 (95% CI, 1.8-6.7)), neonatal admission (OR, 2.23 (95% CI, 1.23-4.05)), hypoglycemia (OR, 9.5 (95% CI, 1.8-49.8)) and hyperbilirubinemia (OR, 9.0 (95% CI, 4.6-17.6)). Despite similar false-positive rates (FPRs) (6.4% vs 8.2%), false-positive rates (FPRs) detection rates were superior at 36 vs 32 weeks' gestation (sensitivity, 38.8% vs 22.5%; P = 0.006), with positive and negative likelihood ratios of 6.1 vs 2.7 and 0.65 vs 0.84, respectively. In cases of severe FGR, FPRs for both scans were also similar (8.5% vs 8.7%), but detection rates were superior at 36 vs 32 weeks' gestation (61.4% vs 32.5%; P = 0.008). Positive and negative likelihood ratios were 7.2 vs 3.7 and 0.4 vs 0.74, respectively. 3
27. Manning FA. The use of sonography in the evaluation of the high-risk pregnancy. Radiol Clin North Am. 1990;28(1):205-216 Review/Other-Dx N/A To review the role of dynamic ultrasound fetal assessment and fetal biophysical profile scoring in the recognition and management of the high-risk pregnancy. No results stated in abstract. 4
28. Carter EB, Goetzinger K, Tuuli MG, et al. Evaluating the Optimal Definition of Abnormal First-Trimester Uterine Artery Doppler Parameters to Predict Adverse Pregnancy Outcomes. J Ultrasound Med. 2015;34(7):1265-1269. Observational-Dx 1192 pregnant women To investigate the optimal definition of abnormal first-trimester uterine artery Doppler parameters associated with adverse pregnancy outcomes Of 1192 patients with complete outcome data, preeclampsia was seen in 8.4%, early preeclampsia in 1.8%, preterm birth in 12.9%, early preterm birth in 5.6%, and small for gestational age (SGA) in 8.5%. A mean PI above the 75th percentile (>1.91) was the best index for predicting early preeclampsia (sensitivity, 45.0%; specificity, 75.5%; negative predictive value (NPV), 98.7%; ROC area, 0.65). A mean PI above the 75th percentile was also the best index for predictive early preterm birth (sensitivity, 40.0%; specificity, 76.0%; NPV, 95.5%; ROC area, 0.65). None of the parameters were significant for predicting SGA. 3
29. Parry S, Sciscione A, Haas DM, et al. Role of early second-trimester uterine artery Doppler screening to predict small-for-gestational-age babies in nulliparous women. Am J Obstet Gynecol. 2017;217(5):594 e591-594 e510. Observational-Dx 8050 patients To determine the utility of early second-trimester uterine artery Doppler studies as a predictor of small-for-gestational-age neonates. Uterine artery Doppler indices, birthweight, and gestational age at birth were available for 8024 women. Birthweight <5th percentile for gestational age occurred in 358 (4.5%) births. Typical thresholds for the uterine artery Doppler indices were all associated with birthweight <5th percentile for gestational age (P < .0001 for each), but the positive predictive values for these cutoffs were all <15% and areas under receiver operating characteristic curves ranged from 0.50-0.60. Across the continuous scales for these measures, the areas under receiver operating characteristic curves ranged from 0.56-0.62. Incorporating maternal age, early pregnancy body mass index, race/ethnicity, smoking status prior to pregnancy, chronic hypertension, and pregestational diabetes in the prediction model resulted in only modest improvements in the areas under receiver operating characteristic curves ranging from 0.63-0.66. 3
30. Shwarzman P, Waintraub AY, Frieger M, Bashiri A, Mazor M, Hershkovitz R. Third-trimester abnormal uterine artery Doppler findings are associated with adverse pregnancy outcomes. J Ultrasound Med. 2013;32(12):2107-2113. Observational-Dx 198 patients To evaluate the association between third-trimester abnormal uterine artery Doppler findings and pregnancy outcomes. In patients with bilateral pathologic uterine artery Doppler waveforms, the rates of cesarean delivery, small-for-gestational-age (SGA) neonates, preterm delivery, and low Apgar scores were increased compared to patients with normal or pathologic unilateral waveforms (P = .009; P > .001; P = .007; P > .001, respectively). The incidence rates for SGA neonates, cesarean delivery, and preterm delivery were significantly higher among patients without intrauterine growth restriction in previous pregnancies (IUGR) or preeclampsia toxemia when associated with pathologic bilateral waveforms in comparison to normal waveforms (P = .01 for all). A bilateral pathologic waveform was found to be an independent risk factor for cesarean delivery and SGA neonates. The incidence rates for SGA neonates and preterm delivery were significantly higher among patients with IUGR and/or preeclampsia toxemia when associated with bilateral abnormalities in comparison to normal waveforms (P = .01 for both). 3
31. Newnham JP, Patterson LL, James IR, Diepeveen DA, Reid SE. An evaluation of the efficacy of Doppler flow velocity waveform analysis as a screening test in pregnancy. Am J Obstet Gynecol. 1990;162(2):403-410. Observational-Dx 535 medium-risk pregnancies Prospective double-blind study to evaluate the efficacy of uterine and umbilical Doppler waveform analysis as a screening test for development of fetal hypoxia and IUGR. Uteroplacental systolic to diastolic ratios at 24 weeks was associated with subsequent fetal hypoxia. Sensitivity 24%, specificity 94%, 70% of abnormal tests did not have fetal hypoxia. UA systolic to diastolic ratio at 24-34 weeks was predictive of IUGR, but only weakly if no hypoxia. Favors role for uteroplacental and UA Doppler in high-risk pregnancies, but not as a primary screening test for low risk pregnancies. 3
32. American College of Radiology. ACR Appropriateness Criteria®: Assessment of Fetal Well-Being. Available at: Review/Other-Dx N/A Evidence-based guidelines to assist referring physicians and other providers in making the most appropriate imaging or treatment decision for a specific clinical condition. No abstract available. 4
33. Lesmes C, Gallo DM, Saiid Y, Poon LC, Nicolaides KH. Prediction of small-for-gestational-age neonates: screening by uterine artery Doppler and mean arterial pressure at 19-24 weeks. Ultrasound Obstet Gynecol. 2015;46(3):332-340. Observational-Dx 63,975 pregnancies; 60,273 cases To investigate the potential value of uterine artery (UtA) pulsatility index (PI) and mean arterial pressure (MAP) at 19-24 weeks' gestation, in combination with maternal characteristics and medical history and fetal biometry in the prediction of delivery of small-for-gestational-age (SGA) neonates in the absence of pre-eclampsia (PE) and to examine the potential value of such assessment in deciding whether the third-trimester scan should be performed at 32 and/or 36 weeks' gestation The detection rates (DRs) of combined screening by maternal factors, fetal biometry and UtA-PI at 19-24 weeks were 90%, 68% and 44% for SGA < 5(th) delivering < 32, 32-36 and >/= 37 weeks' gestation, respectively, at a false-positive rate (FPR) of 10%. The performance of screening was not improved by the addition of MAP. The DR of SGA < 5(th) delivering at 32-36 weeks improved from 68% to 90% with screening at 32 rather than at 19-24 weeks. Similarly, the DR of SGA < 5(th) delivering >/= 37 weeks improved from 44% with screening at 19-24 weeks to 59% and 76% when screening at 32 and 36 weeks, respectively. In a hypothetical model, it was estimated that if the desired objective of prenatal screening is to predict about 80% of the cases of SGA < 5(th) , it would be necessary to select 17% of the population at the 19-24-week assessment to be reassessed at 32 weeks and 38% to be reassessed at 36 weeks; 62% would not require a third-trimester scan. 3
34. Cruz-Martinez R, Savchev S, Cruz-Lemini M, Mendez A, Gratacos E, Figueras F. Clinical utility of third-trimester uterine artery Doppler in the prediction of brain hemodynamic deterioration and adverse perinatal outcome in small-for-gestational-age fetuses. Ultrasound Obstet Gynecol. 2015;45(3):273-278. Observational-Dx 327 SGA fetuses To assess the clinical value of third-trimester uterine artery (UtA) Doppler ultrasound in the prediction of hemodynamic deterioration and adverse perinatal outcome in term small-for-gestational-age (SGA) fetuses. Abnormal UtA Doppler at diagnosis of SGA was associated with a higher risk of developing abnormal brain Doppler indices before induction of labor than in those with a normal UtA at diagnosis (62.7% vs 34.6%, respectively; P < 0.01). Compared to those with normal UtA Doppler indices, those with abnormal UtA Doppler findings were associated with a higher risk of intrapartum Cesarean section (52.2% vs 37.3%, respectively; P = 0.03), Cesarean section for non-reassuring fetal status (NRFS) (35.8% vs 23.1%, respectively; P = 0.03), neonatal acidosis (10.4% vs 7.7%, respectively; P = 0.47) and neonatal hospitalization (23.9% vs 16.5%, respectively; P = 0.16). Logistic regression analysis indicated that UtA Doppler findings were not significantly associated with adverse perinatal outcome independent of brain Doppler findings 2
35. Alfirevic Z, Neilson JP. Doppler ultrasonography in high-risk pregnancies: systematic review with meta-analysis. Am J Obstet Gynecol. 1995;172(5):1379-1387. Meta-analysis 12 randomized controlled trials To review all available (published and unpublished) randomized controlled trials of Doppler ultrasonography of the umbilical artery in high-risk pregnancies. Meta-analysis shows a significant reduction in the number of antenatal admissions (44%, 95% confidence interval 28% to 57%), inductions of labor (20%, 95% confidence interval 10% to 28%), and cesarean sections for fetal distress (52%, 95% confidence interval 24% to 69%) in the Doppler group and that the clinical action guided by Doppler ultrasonography reduces the odds of perinatal death by 38% (95% confidence interval 15% to 55%). The reduction in perinatal deaths was also observed in five mortality subgroups (i.e., stillbirths, neonatal deaths, deaths of normally formed babies, normally formed stillbirths, and deaths of normally formed neonates). Post hoc analyses revealed a statistically significant reduction in elective delivery, intrapartum fetal distress, and hypoxic encephalopathy in the Doppler group. M
36. Figueras F, Savchev S, Triunfo S, Crovetto F, Gratacos E. An integrated model with classification criteria to predict small-for-gestational-age fetuses at risk of adverse perinatal outcome. Ultrasound Obstet Gynecol. 2015;45(3):279-285. Observational-Dx 509 fetuses To develop an integrated model with the best performing criteria for predicting adverse outcome in small-for-gestational-age (SGA) pregnancies. An adverse outcome occurred in 134 (26.3%) cases. The best performing predictors for defining a high risk for adverse outcome in SGA fetuses was the presence of a cerebroplacental ratio (CPR)< 10th centile, a mean mean uterine artery (UtA)-pulsatility index (PI) > 95th centile or an estimated fetal weight (EFW) < 3rd centile. The algorithm showed a sensitivity, specificity and positive and negative predictive values for adverse outcome of 82.8% (95% confidence interval (CI), 75.1-88.6%), 47.7% (95% CI, 42.6-52.9%), 36.2% (95% CI, 30.8-41.8%) and 88.6% (95% CI, 83.2-92.5%), respectively. Positive and negative likelihood ratios were 1.58 and 0.36. 2
37. Isalm ZS, Dileep D, Munim S. Prognostic value of obstetric Doppler ultrasound in fetuses with fetal growth restriction: an observational study in a tertiary care hospital. J Matern Fetal Neonatal Med. 2015;28(1):12-15. Observational-Dx 253 cases To determine the prognostic value of umbilical artery Doppler (UAD) with fetal growth restriction (FGR) and their perinatal outcomes. The perinatal morality rate was 3.2%. Neonates with abnormal Doppler were at increased risk of cesarean delivery, low birth weights and low Apgar scores. Among the perinatal morbidity, neonatal intensive care unit (NICU) admission was 4.2 and 15.3 times in neonates with reduced end diastolic flow (REDF) and Absent/Reverse End Diastolic Flow (AREDF) and similarly the perinatal mortality of AREDF was 12.5 times higher as compared to Normal End Diastolic Flow (NEDF). Other morbidities were also much higher in abnormal Doppler groups. 3
38. Siddiqui TS, Asim A, Ali S, Tariq A. Comparison of perinatal outcome in growth restricted fetuses retaining normal umbilical artery Doppler flow to those with diminished end-diastolic flow. J Ayub Med Coll Abbottabad. 2014;26(2):221-224. Observational-Dx 60 patients To compare perinatal outcome in growth restricted fetuses retaining normal umbilical artery Doppler flow to those with diminished or severely reduced/absent end-diastolic flow. Umbilical artery Doppler velocimetry showed a significant correlation with the perinatal outcome. In 90% of cases of Intrauterine growth restriction /retardation (IUGR) having abnormal waveform, poor perinatal outcome was seen as compared to only 33.3% retaining normal Doppler flow. 3
39. O'Dwyer V, Burke G, Unterscheider J, et al. Defining the residual risk of adverse perinatal outcome in growth-restricted fetuses with normal umbilical artery blood flow. Am J Obstet Gynecol. 2014;211(4):420 e421-425. Observational-Dx 1116 patients To determine the cause of adverse perinatal outcome in fetal growth restriction (FGR) where umbilical artery (UA) Doppler was normal, as identified from the Prospective Observational Trial to Optimize Pediatric Health (PORTO). In all, 57 (5.0%) of the 1116 fetuses had an adverse perinatal outcome. Nine (1.3%) of 698 fetuses with normal UA Doppler had an adverse outcome, compared with 48 (11.5%) of 418 with abnormal UA Doppler (P < .0001). There were 2 perinatal deaths in the normal group and 6 in the abnormal group (P = .01). The perinatal deaths in the normal group were 1 case of pulmonary hypoplasia after prolonged preterm rupture of the membranes from 12 weeks' gestation and a case of placental abruption. Gestation at delivery was 33 +/- 3 vs 31 +/- 4 weeks (P = .05) and mean birthweight was 1830 +/- 737 vs 1146 +/- 508 g (P = .001) in the respective groups. Neonatal sepsis was the commonest adverse outcome in both groups: 0.1% and 0.4%, respectively (P = .01). 3
40. Unterscheider J, Daly S, Geary MP, et al. Predictable progressive Doppler deterioration in IUGR: does it really exist? Am J Obstet Gynecol. 2013;209(6):539 e531-537. Observational-Dx 1116 nonanomalous fetuses To study Doppler changes in multiple vessels including UA, MCA, DV, AoI, and myocardial performance index (MPI) and to establish whether a predictable progressive sequence of Doppler deterioration exists at the level of the individual fetus and to determine any added benefit in applying these Doppler assessments in IUGR informing surveillance intervals and timing of delivery. optimal surveillance of fetuses with an estimated fetal weight (EFW) less than the 10th centile Our study of 1116 nonanomalous fetuses comprised 7769 individual Doppler data points. Five hundred eleven patients (46%) had an abnormal UA, 300 (27%) had an abnormal MCA, and 129 (11%) had an abnormal DV Doppler. The classic pattern from abnormal UA to MCA to DV existed but no more frequently than any of the other potential pattern. Doppler interrogation of the UA and MCA remains the most useful and practical tool in identifying fetuses at risk of adverse perinatal outcome, capturing 88% of all adverse outcomes. 3
41. Lee VR, Pilliod RA, Frias AE, Rasanen JP, Shaffer BL, Caughey AB. When is the optimal time to deliver late preterm IUGR fetuses with abnormal umbilical artery Dopplers? J Matern Fetal Neonatal Med. 2016;29(5):690-695. Review/Other-Dx 10,000 women To determine the optimal timing of delivery in late preterm intrauterine growth restriction (IUGR) fetuses with abnormal umbilical artery Doppler (UAD) indices. The optimal gestational age (GA) for delivery is 35 weeks, which minimized perinatal deaths and maximized total quality-adjusted life years (QALYs). Earlier delivery became optimal once the risk of stillbirth was threefold our baseline assumption; our model was also robust until the risk of absent or reversed end-diastolic flow (AREDF) at 35 weeks was half our baseline assumption, after which delivery at 36 weeks was preferred. Delivery at 35 weeks was the optimal strategy in 77% of trials in Monte Carlo multivariable sensitivity analysis. 4
42. Dahlke JD, Mendez-Figueroa H, Maggio L, Albright CM, Chauhan SP, Wenstrom KD. Early term versus term delivery in the management of fetal growth restriction: a comparison of two protocols. Am J Perinatol. 2015;32(6):523-530. Observational-Dx 540 pregnancies To compare two management protocols in pregnancies diagnosed with fetal growth restriction (FGR). There were 228 and 312 women in the early term and term protocol, respectively, who met inclusion criteria. Compared with the early term group, the term group had an increased median gestational age (GA) at delivery (37.1 vs. 38.6%, p < 0.001), decreased deliveries less than 37(0/7) weeks (37 vs. 24%, p = 0.01) and decreased neonatal intensive care unit (NICU) admissions (38 vs. 28%, p = 0.02). 3
43. Maggio L, Dahlke JD, Mendez-Figueroa H, Albright CM, Chauhan SP, Wenstrom KD. Perinatal outcomes with normal compared with elevated umbilical artery systolic-to-diastolic ratios in fetal growth restriction. Obstet Gynecol. 2015;125(4):863-869. Observational-Dx 11,785 pregnancies To compare the composite neonatal morbidity of pregnancies with fetal growth restriction (estimated fetal weight less than the 10th percentile) and normal compared with elevated umbilical artery systolic-to-diastolic ratios. Of 11,785 pregnancies evaluated, 789 (7%) were diagnosed with fetal growth restriction. Among 512 that met inclusion criteria, 394 (77%) had normal and 118 (23%) had elevated umbilical artery systolic-to-diastolic ratios. When fetal growth-restricted pregnancies with elevated umbilical artery systolic-to-diastolic ratios were delivered at 37 weeks of gestation were compared with those with normal umbilical artery systolic-to-diastolic ratios delivered at 39 weeks of gestation, there was no difference in the rate of neonatal intensive care unit admission (101 [25.7%] compared with 51 [43.2%]; crude odds ratio [OR] 2.5, 95% confidence interval 1.5-4.0; adjusted OR 1.37, 95% CI 0.69-2.71) or composite neonatal morbidity (60 [15.2%] compared with 24 [20.3%]; crude OR 1.42, 95% CI 0.84-2.40; adjusted OR 0.91, 95% CI 0.45-1.84). 4
44. Korkalainen N, Rasanen J, Kaukola T, Kallankari H, Hallman M, Makikallio K. Fetal hemodynamics and adverse outcome in primary school-aged children with fetal growth restriction: a prospective longitudinal study. Acta Obstet Gynecol Scand. 2017;96(1):69-77. Observational-Dx 72 patients To hypothesize that the adverse outcome of Fetal growth restriction (FGR) children at primary school age is associated with abnormalities in placental and fetal central and peripheral circulations. Fetal growth restriction children with adverse long-term outcome were delivered earlier and with lower birthweights than were those with non-compromised outcome. Seventy percent of the fetal growth restriction group showed non-compromised long-term outcomes and participated in mainstream education at the appropriate age level. Absent/retrograde diastolic flow in the umbilical artery (p < 0.001), negative A-wave in the ductus venosus (p = 0.006), cardiomegaly (p = 0.02), hydrops (p = 0.006) and cardiovascular profile score <6 (p = 0.002) were associated with increased risk of adverse outcome. After adjustment for gestational age, these parameters demonstrated hazard ratios of 5.0-16.5 for adverse long-term outcome; increased systemic venous pulsatility and low cardiovascular profile score had the highest predictive power. 2
45. Lakshmi CV, Pramod G, Geeta K, et al. Outcome of very low birth weight infants with abnormal antenatal Doppler flow patterns: a prospective cohort study. Indian Pediatr. 2013;50(9):847-852. Observational-Dx 238 infants To determine outcomes of preterm infants with history of absent/reversed end-diastolic umbilical artery Doppler flow (AREDF) vs. infants with forward end-diastolic flow (FEDF). At 40 weeks adjusted post-menstrual age, AREDF vs. FEDF group had a higher risk for death in the Neonatal intensive care unit (NICU) (12% vs. 1%), respiratory distress syndrome (33% vs. 19%), and cystic periventricular leukomalacia (12% vs. 1%). At 12-18 months corrected age, AREDF vs. FEDF group had a trend towards increased risk for cerebral palsy (7% vs. 1%, P=0.06). After logistic regression analysis, adjusting for confounders, AREDF was independently associated only with mortality in the NICU. 2
46. Meher S, Hernandez-Andrade E, Basheer SN, Lees C. Impact of cerebral redistribution on neurodevelopmental outcome in small-for-gestational-age or growth-restricted babies: a systematic review. Ultrasound Obstet Gynecol. 2015;46(4):398-404. Review/Other-Dx 9 studies To review systematically the evidence on impact of cerebral redistribution, as assessed by fetal middle cerebral artery (MCA) Doppler, on neurological outcomes in small-for-gestational-age (SGA) or growth-restricted fetuses. The search yielded 1180 possible citations, of which nine studies were included in the review, with a total of 1198 fetuses. Definitions of SGA and cerebral redistribution were variable, as was study quality. Data could not be synthesized in meta-analyses because of heterogeneity in outcome reporting. Cerebral redistribution was not associated with increased risk of intraventricular hemorrhage in neonates (five studies; n = 806). When present in preterm fetuses, cerebral redistribution was associated with normal Neonatal Behavioral Assessment Scale (NBAS) scores at 40 weeks (one study; n = 62) but abnormal psychomotor development at 1 year of age on the Bayley scale (one study; n = 172). When present in term SGA fetuses, cerebral redistribution was associated with increased risk of motor and state organizational problems on NBAS (two studies; n = 158), and lower mean percentile scores in communication and problem solving at 2 years of age on the Ages and Stages Questionnaire (one study; n = 125). 4
47. Lees CC, Marlow N, van Wassenaer-Leemhuis A, et al. 2 year neurodevelopmental and intermediate perinatal outcomes in infants with very preterm fetal growth restriction (TRUFFLE): a randomised trial. Lancet. 2015;385(9983):2162-2172. Observational-Dx 542 women To assess whether changes in the fetal ductus venosus Doppler waveform (DV) could be used as indications for delivery instead of cardiotocography short-term variation (STV). Between Jan 1, 2005 and Oct 1, 2010, 503 of 542 eligible women were randomly allocated to monitoring groups (166 to cardiotocograph (CTG) short-term variation (STV), 167 to DV p95, and 170 to DV no A). The median gestational age at delivery was 30.7 weeks (IQR 29.1-32.1) and mean birthweight was 1019 g (SD 322). The proportion of infants surviving without neuroimpairment did not differ between the CTG STV (111 [77%] of 144 infants with known outcome), DV p95 (119 [84%] of 142), and DV no A (133 [85%] of 157) groups (ptrend=0.09). 12 fetuses (2%) died in utero and 27 (6%) neonatal deaths occurred. Of survivors, more infants where women were randomly assigned to delivery according to late ductus changes (133 [95%] of 140, 95%, 95% CI 90-98) were free of neuroimpairment when compared with those randomly assigned to CTG (111 [85%] of 131, 95% CI 78-90; p=0.005), but this was accompanied by a non-significant increase in perinatal and infant mortality. 2
48. Bilardo CM, Hecher K, Visser GHA, et al. Severe fetal growth restriction at 26-32 weeks: key messages from the TRUFFLE study. Ultrasound Obstet Gynecol. 2017;50(3):285-290. Review/Other-Dx N/A No abstract available. No abstract available. 4
49. Visser GHA, Bilardo CM, Derks JB, et al. Fetal monitoring indications for delivery and 2-year outcome in 310 infants with fetal growth restriction delivered before 32 weeks' gestation in the TRUFFLE study. Ultrasound Obstet Gynecol. 2017;50(3):347-352. Observational-Dx 310 patients To investigate the indications for delivery in relation to 2-year outcome in infants delivered before 32 weeks to further refine management proposals. Overall, only 32% of liveborn infants were delivered according to the specified monitoring parameter for indication for delivery; 38% were delivered because of safety-net criteria, 15% for other fetal reasons and 15% for maternal reasons. In the CTG-STV group, 51% of infants were delivered because of reduced STV. In the DV-p95 group, 34% of infants were delivered because of abnormal DV and, in the DV-no-A group, only 10% of infants were delivered accordingly. The majority of infants in the DV groups were delivered for the safety-net criterion of spontaneous decelerations in FHR. Two-year intact survival was highest in the DV groups combined compared with the CTG-STV group (P = 0.05 for live births only, P = 0.21 including fetal death), with no difference between DV groups. A poorer outcome in the CTG-STV group was restricted to infants delivered because of FHR decelerations in the safety-net subgroup. Infants delivered because of maternal reasons had the highest birth weight and a non-significantly higher intact survival. 4
50. American College of Radiology. ACR–SPR Practice Parameter for the Safe and Optimal Performance of Fetal Magnetic Resonance Imaging (MRI). Available at: Review/Other-Dx N/A To promote safe and optimal performance of fetal magnetic resonance imaging (MRI). No abstract available. 4
51. American College of Radiology. ACR-SPR Practice Parameter for Imaging Pregnant or Potentially Pregnant Adolescents and Women with Ionizing Radiation. Available at: Review/Other-Dx N/A To assist practitioners in providing appropriate radiologic care for pregnant or potentially pregnant adolescents and women by describing specific training, skills and techniques. No abstract available. 4
52. American College of Radiology. ACR-ACOG-AIUM-SRU Practice Paramater for the Performance of Obstetrical Ultrasound. Available at: Review/Other-Dx N/A To promote the safe and effective use of diagnostic and therapeutic radiology by describing the key elements of standard ultrasound examinations in the first, second, and third trimesters of pregnancy. No abstract available. 4
53. American College of Radiology. Manual on Contrast Media. Available at: Review/Other-Dx N/A To assist radiologists in recognizing and managing risks associated with the use of contrast media. No abstract available. 4
54. Expert Panel on MR Safety, Kanal E, Barkovich AJ, et al. ACR guidance document on MR safe practices: 2013. J Magn Reson Imaging. 37(3):501-30, 2013 Mar. Review/Other-Dx N/A To help guide MR practitioners regarding MR safety issues and provide a basis for them to develop and implement their own MR policies and practices. No abstract available. 4
55. American College of Radiology. ACR Appropriateness Criteria® Radiation Dose Assessment Introduction. Available at: Review/Other-Dx N/A To provide guidelines on exposure of patients to ionizing radiation. No abstract available. 4