Prenatal Diagnostic Sonography

Abend Weinger Marta MD Neonatology department Bnai Zion Hospital

 To date the prevalent practice is to report the US findings and to state the risk of malformed baby   The professional liability oblige to report The report may cause a great deal of anxiety to mother   Both sides of argument are well intentioned What is the good way?

Isoleted echogenic heart focus C.Coco – J.US Med.23:2004

 The consistent histologic finding is mineralization within papillary muscle  Various works have shown that there is no correlation to heart pathologic anomalies  Persistence after birth is not associated with cardiac anomalies  In 1994 Brown et all.reported CEF associated with trisomy 21(in pathology literature)  Numerous studies have attempted to quantify the risk, as well as the frequency of the finding

 Objective: to evaluate the risk of Down syndrome in fetuses with heart echogenic focus and likelihood ratios in an unselected population  Method: prospective evaluation of 12,672 second trimester sonographic features were examined. Population with echogenic focus was checked for chromosomal anomalies

 Results:Table 1+2+3  Discution: the prevalence of trisomy among fetuses with CEF 0.62%, higher than without CEF 0.065%

 The decision to performed amniocentesis on all fetuses with CEF- fetal loss 1/200  If restricted to CEF+associated anomalies only 46 kariotype need- calculated fetal loss 0.23%  Conclusion: CEF+ other major or minor anomalies justifies amniocentesis  Amniocentesis need not to be offer to patients at low risk with CEF

The significans of isolated choroid plexus cysts

 In 1984 was published the initial report on prenatal US detection of choroid plexus cyst  It was thought to be a finding without pathologic significance  Two years later the association with trisomy 18 was first suggested  In nearly two decades a large volume of literature has been published

 The clinical dilemma is between invasive genetic testing against potential missing a major aneuploidy  Two recent review articles summarized the literature: nine of the articles in 1 of these reviews recommended genetic testing, whereas 11 others concluded that was not indicated

 AIUM published standards for second trimester antenatal US examination  Some people recommend extended anatomic survey when ICPC found (EX : fetal hands)

Choroid plexus cyst and Echogenic intracardiac focus. J/US Med 23:2004

 These two markers have been the source of the greatest controversy as signs for aneuploidy  The EIF is considered a soft marker for trisomies 21 and 13, whereas the CPC is considered marker for trisomy 18  Large no. of practitioners feel that the reporting of these 2 findings cause more harm than good  The AIUM and SRU offer a compromise as guide line:

  The recommendation is: When CPC or EIF is identified without other minor or major anomalies - In the absence of other risk factors this is considered a normal variant,and no further evaluation is recommended  Risk status is ascertained preferably by the patients biochemical screening test results (the so-called triple or quadruple markers) and maternal age  The AIUM guidelines should be strictly followed

Outcome of fetuses with Club Feet J.US Med.23:2004

  One of the most common birth defect 1\1000 of live births  Clubfoot (talipes equinovarus) – malformation of the bones of ankle and foot inverted and rotated medially US DG: the bones of the foot lie in the same plane as the lower leg bones

 CF is commonly associated with other fetal anomalies and aneuploidy. Could be syndrome or genetic defect  Other causes of CF: uteral anomalies, restricted environment in utero, olygohydramnios

   The purpose of the study: to evaluate the outcome of fetuses with prenatally diagnosed clubfoot with attention to the difference between uni- and bilateral CF Method:identification of all fetuses scanned during 3 years in whom CF was suspected .or dg.prenatally

Collection of maternal and NN medical records: unilateral or bilateral CF, gestational age at dg., other sonographic findings, outcome and neonatal findings at birth

   RESULTS: 121 fetuses had prenatal dg. or susp. clubfoot 87 study cases :51 evaluated from NN records and 36 from pathology   48% had unilateral ,52% bilateral clubfoot False positive was significantly higher in unilateral group

 Other anomalies were more common with bilateral CF (76% vs. 55%)  The most common anomalies: musculo-skeletal, neural tube defects and cardio-vascular anomalies   The rate of aneuploidy was similar in the 2 groups Conclusion: fetuses with antenatal DG of clubfoot often have other anomalies, aneuploidy or both

 The risk of aneuploidy should be discussed with the patient and amniocentesis should be considered  The rate of false positive prenatal US dg. in fetuses with unilateral CF. is higher than bilateral

Prenatal dg. of fetal pyelectasis

 Pyelectasis is one of the most common DG in prenatal period (2-5%)  Reports on threshold of renal AP diameter which warrants pre- and postnatal FU are conflicting  Some of reports suggested thresholds varying from 4-10 mm to be associated with abnormal function  The reason for conflicting threshold is a poor understanding of the natural history of these DG

Prenatal mild pyelectasis J.US Med 23: 2004

 Objective: to evaluate the threshold of renal pelvic diameter associated with normal postnatal renal function  Methods: a retrospective review of US database conducted over a 3 years period for cases of mild pyelectasis diagnosed between 18 to 32 W  Results:7416 women were evaluated and 150 cases were identified with pyelectasis (2%)  Persistent postnatal renal anomalies were seen in 20 of these cases (30%)

 For purpose of the study, cases with pyelectasis of greater than 10 mm, multiple anomalies and aneuploidy were excluded  The renal pelvic AP thresholds evaluated included diameters of 6,7,8,9 mm

 The renal threshold that best predicted normal postnatal outcome was an AP diameter of

less than 7 mm at 32 W

(sensitivity and specificity of 87% and 85% , odds ratio 0.31)  Conclusion: in FU of fetuses with mild pyelectasis, renal pelvic AP diameter of 7 mm or less at 32 W is highly predictive of normal renal function

Frequency and nature of anomalies in fetuses with single umbilical arteries J .US. Med 1998: dec.

 Retrospective study of SUA+frequency and nature of sonographic anomalies  Study population 167 cases  GA at dg. range 17-41W.  37cases (31%) had structural abnormalities of multiple organs: heart (19), GI tract (14), CNS (9), abnormal karyotypes (5)

 Among 85 with apparently isolated SUA, 6 more had anomalies that were found only at birth (7%)  Even when SUA is apparently isolated finding, prove that there are no other structural anomalies

Do well infant born with isolated SUA need investigation?

Arch.dis.chid. 12.2004

 The source: Medline. A total of 477 articles found  152 English articles, human NN studies  A systematic review with meta-analysis was done  Clinical bottom line:

 There is an increased proportion of significant occult renal malformations in asymptomatic infants with SUA   A significant proportion may have VUR (gr 2 or >) Screening US and cystogram is needed to detect renal anomalies  There is a lack of data regarding other organ malformations