How MRI and Ultrasound Works
- Magnetic resonance imaging (MRI) does not use X-rays to take images of body organs.
- It is possible to take pictures of any part of the body at almost any angle using MRI.
- Ultrasound uses high frequency sound waves to create images of various body parts and organs.
- Both MRI and ultrasound are non-invasive procedures.
MRI vs. Ultrasound
- Neonatal cranial ultrasound is used in detecting brain injury in preterm infants and can be used repetitively without harming the infant.
- MRI is used for the same purpose of imaging the brain but it is time consuming and is hardly used repetitively.
- Ultrasound scans help in determining the extent of intracranial hemorrhage.
- Ultrasound is fast and inexpensive and can be done at the bedside without any side effects.
- MRI is expensive, time consuming and resource consuming thus not readily available.
- MRI is however better in predicting adverse neurodevelopmental outcomes even at the age of 2 years compared to cranial ultrasound.
- Conventional MRI is powerful in detecting white matter abnormalities and analyzing effects in preterm babies, but ultrasound cannot.
- There is difficulty in establishing superiority of MRI at term to sequential cranial ultrasound from birth to term.
- Cranial ultrasound in very low birth weight infants has high reliability in determining cystic white matter injury.
- However, it is poor in detecting non-cystic injuries, which are more common.
- MRI however at term is sensitive enough to WM injury of non-cystic form.
General Observations
- Conventional MRI adds insignificant clinical information to term age infants with normal cranial ultrasound.
- Ultrasound therefore emerges as not only beneficial but also cost effective than MRI in detecting low risk disabilities.
- MRI techniques can however be useful in detecting abnormalities at an earlier age in infants.
- Ultrasound has been widely used in effective detection of abnormal motor development.
Conclusion
- Ultrasound is highly favored in sensing severe abrasions of white matter in preterm infants.
- MRI is however useful for diagnosis of less severe damage.
- MRI is very effective for final diagnosis at term if it is done within 3 weeks of life.
- MRI has the potential of detecting a wide range of white and gray matter defects and it should be considered on a routine basis for preterm babies.
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