Fetal middle cerebral arterial Doppler assessment
Fetal middle cerebral arterial (MCA) Doppler assessment is an important part of assessing fetal cardiovascular distress, fetal anaemia or fetal hypoxia. In the appropriate situation it is a very useful adjunct to umbilical artery Doppler assessment. It is also used in the additional work up of
- intra-uterine growth restriction (IUGR)
- twin to twin transfusion syndrome (TTTS) 5
- twin anaemia polycythaemia sequence (TAPS)
For an accurate measurement, the fetal head should be in the transverse plane. The MCA vessels are often found with colour or power Doppler ultrasound overlying the anterior wing of the sphenoid bone near the base of the skull. An angle of insonation of < 15o should be used; typically, an angle that approximates zero degrees can be achieved by moving the transducer on the maternal abdomen.
Paramaters used include
- fetal MCA time averaged mean velocity (TAMV)
- fetal MCA pulsality index (PI)
- fetal MCA peak systolic velocity (PSV) - the highest velocity should be recorded
- fetal MCA systolic/diastolic (S/D) ratio - a normal fetal MCA S:D ratio should always be higher than the umbilical arterial S:D ratio.
- in the normal situation the fetal MCA has a high resistance flow which means there is minimal antegrade flow in fetal diastole.
- in pathological states this can turn into a low resistance flow mainly as a result of the fetal head sparing theory.
- paradoxically in some situations such as with severe cerebral oedema, the flow can revert back to a high resistance pattern when the pathology hasn't yet resolved.
- 1. Mari G, Hanif F. Fetal Doppler: umbilical artery, middle cerebral artery, and venous system. Semin. Perinatol. 2008;32 (4): 253-7. doi:10.1053/j.semperi.2008.04.007 - Pubmed citation
- 2. Baschat AA, Gembruch U, Harman CR. The sequence of changes in Doppler and biophysical parameters as severe fetal growth restriction worsens. Ultrasound Obstet Gynecol. 2001;18 (6): 571-7. doi:10.1046/j.0960-7692.2001.00591.x - Pubmed citation
- 3. Moise KJ. The usefulness of middle cerebral artery Doppler assessment in the treatment of the fetus at risk for anemia. Am. J. Obstet. Gynecol. 2008;198 (2): 161.e1-4. doi:10.1016/j.ajog.2007.10.788 - Pubmed citation
- 4. Fong KW, Ohlsson A, Hannah ME et-al. Prediction of perinatal outcome in fetuses suspected to have intrauterine growth restriction: Doppler US study of fetal cerebral, renal, and umbilical arteries. Radiology. 1999;213 (3): 681-9. Radiology (full text) - Pubmed citation
- 5. Suzuki S, Sawa R, Yoneyama Y et-al. Fetal middle cerebral artery Doppler waveforms in twin-twin transfusion syndrome. Gynecol. Obstet. Invest. 1999;48 (4): 237-40. Gynecol. Obstet. Invest. (link) - Pubmed citation
- 6. Abdel-fattah SA, Soothill PW, Carroll SG et-al. Middle cerebral artery Doppler for the prediction of fetal anaemia in cases without hydrops: a practical approach. Br J Radiol. 2002;75 (897): 726-30. Br J Radiol (full text) - Pubmed citation
- 7. Rodeck CH, Whittle MJ. Fetal medicine, basic science and clinical practice. Elsevier Health Sciences. (2008) ISBN:0443104085. Read it at Google Books - Find it at Amazon
- 8. Mukherjee GG, Chakravarty S, Pal B et-al. Current Obstetrics & Gynecology. Jaypee Brothers Publishers. (2007) ISBN:8180619966. Read it at Google Books - Find it at Amazon
Synonyms & Alternative Spellings
|Synonyms or Alternative Spelling||Include in Listings?|
|Fetal middle cerebral arterial (mca) Doppler||✗|
|Fetal MCA Doppler assessment||✗|
|Fetal middle cerebral arterial (MCA) Doppler ultrasound assessment||✗|
|Fetal middle cerebral arterial (MCA) Doppler assessment||✗|