• Share
  • Email
  • Embed
  • Like
  • Save
  • Private Content
UOG Journal Club: Intra- and interoperator reliability of manual and semi-automated measurements of intracranial translucency
 

UOG Journal Club: Intra- and interoperator reliability of manual and semi-automated measurements of intracranial translucency

on

  • 724 views

This Journal Club presentation provides a summary and discussion of the following free access article published in UOG: ...

This Journal Club presentation provides a summary and discussion of the following free access article published in UOG:

Intra- and interoperator reliability of manual and semi-automated measurements of intracranial translucency.
K. Karl, K.O Kagan, R. Chaoui
Volume 39, Issue 2, Date: February 2012, pages 164-168

This can be accessed here: http://onlinelibrary.wiley.com/doi/10.1002/uog.10137/abstract

Statistics

Views

Total Views
724
Views on SlideShare
724
Embed Views
0

Actions

Likes
0
Downloads
10
Comments
0

0 Embeds 0

No embeds

Accessibility

Categories

Upload Details

Uploaded via as Microsoft PowerPoint

Usage Rights

© All Rights Reserved

Report content

Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
  • Full Name Full Name Comment goes here.
    Are you sure you want to
    Your message goes here
    Processing…
Post Comment
Edit your comment

    UOG Journal Club: Intra- and interoperator reliability of manual and semi-automated measurements of intracranial translucency UOG Journal Club: Intra- and interoperator reliability of manual and semi-automated measurements of intracranial translucency Presentation Transcript

    • UOG Journal Club: February 2012Intra- and interoperator reliability of manual and semi-automated measurements of intracranial translucency K. Karl, K. O. Kagan and R. Chaoui Volume 39, Issue 2, Date: February 2012, pages 164–168 Journal Club slides prepared by Dr Asma Khalil (UOG Editor for Trainees)
    • Spina Bifida 25 3–6 per 10,000 births 25Birth prevalence (/10,000) Birth prevalence (/10,000) 20 20 3-6 per 10,000 • Prenatal diagnosis 15 births • Folic acid fortification 15 10 10 5 5 0 0 1930s1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 1930s Year Rankin J et al., Paediatr Perinat Epidemiol 2000 Centre for Disease Control and Prevention statistics 2011 Boyd PA et al., J Med Screen 2011
    • Open spina Bifida Prenatal Detection History MS AFP Ultrasound* 5% 75% 98% *2nd trimesterMS AFP, maternal serum alpha fetoprotein. Detection rate by ultrasound at 11-14 weeks is 14% Wald N et al., Lancet 1974 Nicolaides KH et al., Lancet 1986 Campbell J et al., Obstet Gynecol 1987 Syngelaki A et al., Prenat Diagn 2011
    • First-trimester detection of open spina bifida using intracranial translucency (IT) Normal Open spina bifida BS,brainstem; BSOB, brainstem–occipital bone distance; f.CM, future cisterna magna; OB,occipital bone; Th, Thalamus. Chaoui R et al., UOG 2011
    • B, brainstem;T, thalamus;M, midbrain; My, medulla oblongata. Chaoui R et al., UOG 2009
    • Normal Open spina bifida Chaoui R et al., UOG 2009
    • Intra- and interoperator reliability of manual and semi-automated measurements of intracranial translucency Karl et al., UOG 2012Retrospective; 116 stored images at 11–13 weeks; IT measurementObjectiveExamine whether the assessment of IT at 11–13 weeks can be further standardized by using the semi-automated NT algorithm, SonoNT®, in comparison to manual measurement.
    • Methodology• 11–13 weeks• Mid-sagittal plane• Dorsoposterior position• Two experienced operators• Twice manually and twice using the semi-automated software (SonoNT®)• Intraoperator and interoperator repeatability BS,brainstem; f.CM, future cisterna magna; OB,occipital bone; Plex.chor., choroid plexus; Th, Thalamus.
    • Manual Semi-automatedThe mean of the two manual measurements of the more experiencedoperator 2 was considered the ‘gold standard’.
    • Methodology - manual measurement• Magnify the image• Place the cursor on the innerborder of the echogenicposterior brainstem border andon the inner border of the 4thventricle choroid plexus•The longest vertical distance inthe middle portion
    • Methodology – semi-automated• Corresponding ‘edge enhancement image’ that reflects thedifferences in brightness rather than the brightness itself• Define the echogenic lines delineating the translucency• Calipers placed automatically on the inner borders (inner–inner)Left and central images show semi-automated measurement of nuchal translucency, Moratalla J et al., UOG 2010
    • Methodology – semi-automated•The measurement algorithm connects every point on one of the two echogenic lines to all points on the other line, then selects the minimum distance for each point• From these minimum distances, it selects the largest as the final translucency measurementLeft and central images show semi-automated measurement of nuchal translucency, Moratalla J et al., UOG 2010
    • IT vs NT semi-automated measurement IT NT• IT has a more complex shape• Risk of incorrect recognition of borders due to neighbouring structures• Vertical borders close to the echogenic edges of the brainstem andchoroid plexus• Lateral borders rather narrow over the IT region• Square frame rather than rectangular• Smaller frame Moratalla J et al., UOG 2010
    • Results Manual Semi-automated Operator 1 Operator 2 Operator 1 Operator 2Median (IQR) (mm) 2.1 (1.9–2.4) 2.1 (1.8–2.3) 2.2 (1.9–2.4) 2.2 (1.8-2.2)Intraoperator SD (mm) 0.091 0.088 0.054 0.067Intraclass correlation 0.940 0.939 0.982 0.971Mean difference (mm) –0.09 Reference* 0.01 –0.09 *The mean of the two manual measurements of operator 2 was considered the ‘gold standard’.
    • Results95% limits of agreement Manual Semi-automatedIntraoperator –0.26 and 0.23 mm –0.17 and 0.17 mmInteroperator & intermethod* –0.34 and 0.17 mm –0.20 and 0.23 mm Good overall agreement with a trend towards larger measurements using the semi-automated approach *versus the gold standard (the mean of the two manual measurements of operator 2 ).
    • Intra- and interoperator reliability of manual and semi-automated measurements of intracranial translucency Karl et al., UOG 2012 Strengths Limitations• SonoNT can be used • Unknown reliability reliably for IT with variations in• Benefit for less gestation and anatomy experienced operators • Possible misdiagnosis• High repeatability of Blake’s pouch cyst as spina bifida
    • Intra- and interoperator reliability of manual and semi-automated measurements of intracranial translucency Karl et al., UOG 2012 Conclusion  Manual IT measurements are reproducible  IT can be assessed reliably using the semi- automated NT algorithm, leading to standardization of the IT assessment process
    • Intra- and interoperator reliability of manual and semi-automated measurements of intracranial translucency Karl et al., UOG 2012 Discussion points• What is the recurrence risk for spina bifida after having one affected pregnancy?• What medical advice should be given to parents regarding a future pregnancy in the above scenario?• If a recurrence occurs, will it always be limited to the fetal spine?• What is the difference between exencephaly, anencephaly and encephalocele?• Can the above be diagnosed with confidence at 11–14 weeks’ gestation by ultrasound?• Is measurement of intracranial translucency (IT) reproducible and reliable enough to be tested in clinical practice?• Do we know how sensitive measurement of IT is in the detection of spina bifida?