The Scan ‘Menu’

Trish Chudleigh

Advanced Practitioner Manager

Cambridge University Hospitals

Rationale for the Scan Menu

to provide consistency in the scan procedure

to specify measuring techniques

to define the range of anatomical structures to be assessed

to provide the minimum assessment that should be undertaken

The NHS FASP Anomaly Screening Service

population pre-screened & low risk for Down’s (or declined screening)

examination focused towards optimising perinatal management pathways

addresses 11 selected conditions

Includes target detection rates

incorporates annual audit

Key Ultrasound Features

gestational age 18+0 – 20+6 weeks - change from ~20 weeks

- no need to recall if scanned ‘early’

appointment time 30 minutes - times currently vary from 10-30 mins, 61% 20mins

- underpins clinical importance of examination

- supports extension of scanning time to incorporate additional views & measurements

Key Ultrasound Features

six specified images recorded & stored- allows audit of examination’s quantitative & qualitative components at local level

- valuable tool for confirming quality

single further scan only, at 23 weeks if first assessment incomplete- when quality compromised by ↑BMI,fibroids, abdominal scarring, fetal position ‘allows’ an incomplete screen

Key Ultrasound Features

range of normal variants extended to include previous ‘markers’, with exception of ↑nuchal fold (Tri 21)

outflow tracts & coronal lips included

fingers, toes, carrying angles, profile not screened

normal renal pelvis increases to 7.0mm

Eleven Auditable Conditions

Condition Detection rate (%)

Anencephaly 98

Open spina bifida 90

Cleft lip 75

Diaphragmatic hernia 60

Gastroschisis 98

Exomphalos 80

Serious cardiac abnormalities 50

Bilateral renal agenesis 84

Lethal skeletal dysplasia 60

Edward’s syndrome (Trisomy 18) 95

Patau’s syndrome (Trisomy 13) 95

Scan Menu – ‘tick list’

Area Views

1, 2 Head and neck HC (Chitty) + suboccipito-bregmatic

3 Face Lips coronal

4-7 Chest 4ch, both outflow tracts, lungs

8-12 Abdomen AC, cord insertion, kidneys, bladder

13-14 Spine Sagittal & transverse, skin covering

15-19 Limbs FL, metacarpals & metatarsals x 2

20-21 Uterine cavity Amniotic fluid, placenta position noted

Scan Menu – fetal biometry

HCChitty et alBr J Obstet Gynaecol 1994101:35-43

ACChitty et alBr J Obstet Gynaecol 1994101:125-131

Scan Menu – fetal biometry

FLChitty et alBr J Obstet Gynaecol 1994101:132-135

small measurements compared to dating scan

(significantly less than 5th centile on national charts)

- refer

Scan Menu – images & diagrams

Scan Menu – other measurements

ISUOG Guideline. Ultrasound Obstet Gynecol 2007;29:109-116 Goldstein et al. Am J Obstet Gynecol 1987:156:1065-9

atrium >10.0mm – refer

nuchal fold >6.0mm - refer

Scan Menu – tick list & referral

echogenic bowel (with density equivalent to bone) – refer

renal pelvic dilatation(AP measurement > 7.0mm) - refer

Scan Menu – tick list limbs

femur – length (one leg only)

hands – metacarpals (right & left)

feet – metatarsals (right & left)

Scan Menu – uterine cavity

amniotic fluid – subjective volume

placenta – visible & position noted

Scan Menu – six images

measured HC & atrium

1 2

measured TCD (+ NF))

3

measured AC

4

measured FL

5

sagittal spine including sacrum & skin covering

6

coronal lips & nasal tip

Conclusions

implementation of national programme should shift emphasis of routine anomaly scan from ‘markers’ to ‘requiring referral’ and from aneuploidy to perinatal management.

adopting scan menu should extend diagnostic capability of anomaly scan rather than diminish it

the scan menu provides an exciting challenge for all health professionals involved along pathway & an opportunity for many sonographers to develop & extend their range of skills