Scan Neonatal Brain Early to Optimize Results

LONDON – Magnetic resonance imaging should be used as early as possible to scan the neonatal brain if there are any unexplained symptoms, or if hemorrhagic or thrombotic lesions are suspected.

In the case of thrombosis, it’s important to scan early to decide whether anticoagulation is required, neonatal imaging expert Dr. Mary A. Rutherford of Imperial College London said at the Excellence in Paediatrics annual meeting.

However, Dr. Rutherford, who trained as a pediatrician, noted that for acquired injuries, the use of conventional MRI should be delayed 1-4 weeks, as hypoxic-ischemic brain injury is easier to detect 7 days after the insult.

MRI can be used for a variety of diagnostic and prognostic reasons in full-term neonates; it can help to establish the cause of symptoms, identify brain abnormalities, and determine the likely timing of any injury to the developing brain, she said. Neonatal MRI can also help predict outcomes, provide information for risk management and, in these days of increased medicolegal vigilance, perhaps help clinicians avoid the threat of litigation.

Today, most clinical departments will have an MRI scanner that uses field strengths of 1.5-3 Tesla, which are fine for neonatal imaging, Dr. Rutherford said. "What you really need," she noted, "is an interested radiologist or radiographer." Myelination occurs during the first 2 years of life, so an experienced pediatric or radiology image interpreter is also required.

As access to MRI scanners may be limited, it’s important to be ready as soon as a scanner is free, Dr. Rutherford advised. This means that the neonate must be suitably prepared prior to the scan. Choral hydrate, given 15 minutes before the scan, may be used to keep the neonate sedated temporarily, and ear protection must be worn. The neonate’s head and body should then be "wrapped and fixed" as carefully as possibly into position inside the scanner, so there is little chance of any waking or movement during the scan.

Ventilation may be needed during the scan, and a pediatric staff member needs to be with the baby at all times. Pulse oximetry can be used to monitor the neonate while the scan is in progress.

"MRI is an expensive technology, and you really want to make sure that you get the best possible results from all the effort that is put in by trying to put a baby into an MRI scanner," Dr. Rutherford said.

A key element to successful scanning is ensuring that the MRI coil used fits as closely as possibly to the neonate’s head. "Poor coil choice or head positioning results in poor image quality," she warned.

Motion is another common reason for poor quality images, so motion-resistant sequences need to be considered. T1-weighted (transverse/sagittal), T2-weighted (transverse), and diffusion-weighted imaging may all be appropriate sequences to use. Magnetic resonance venography and angiography can provide useful information about thrombosis or stroke, respectively.

"In this day and age, all infants with a neonatal encephalopathy require – and deserve to have – the benefit of an MR scan," Dr. Rutherford said. Other candidates for MRI include neonates with seizures, severe jaundice, abnormal cranial ultrasound findings, unexplained neurologic signs, dysmorphic features, and where a co-twin has died in utero.

Neonates with unexplained symptoms or who are at risk of hemorrhagic/thrombotic lesions require prompt MRI, as soon as access to a scanner can be arranged.

"You will also want to image fairly quickly in cases of severe neonatal encephalopathy, especially if you are considering withdrawing active treatment," Dr. Rutherford said.

By contrast, for acquired injuries, she noted, "If we want to get the best possible detection of any acquired injury, then we should think about imaging probably between 1 and 4 weeks post insult." Diffusion-weighted imaging is best for identifying early ischemic lesions.

With regards to preterm neonates, routine MRI scanning is not recommended, but early scanning is perhaps advisable if there are unexplained symptoms or withdrawal of care is being considered.

Dr. Rutherford is the editor of "MRI of the Neonatal Brain," (Philadelphia: Saunders, Ltd., 2001). More information: MRI of the Neonatal Brain.

LONDON – Magnetic resonance imaging should be used as early as possible to scan the neonatal brain if there are any unexplained symptoms, or if hemorrhagic or thrombotic lesions are suspected.

In the case of thrombosis, it’s important to scan early to decide whether anticoagulation is required, neonatal imaging expert Dr. Mary A. Rutherford of Imperial College London said at the Excellence in Paediatrics annual meeting.

However, Dr. Rutherford, who trained as a pediatrician, noted that for acquired injuries, the use of conventional MRI should be delayed 1-4 weeks, as hypoxic-ischemic brain injury is easier to detect 7 days after the insult.

MRI can be used for a variety of diagnostic and prognostic reasons in full-term neonates; it can help to establish the cause of symptoms, identify brain abnormalities, and determine the likely timing of any injury to the developing brain, she said. Neonatal MRI can also help predict outcomes, provide information for risk management and, in these days of increased medicolegal vigilance, perhaps help clinicians avoid the threat of litigation.

Today, most clinical departments will have an MRI scanner that uses field strengths of 1.5-3 Tesla, which are fine for neonatal imaging, Dr. Rutherford said. "What you really need," she noted, "is an interested radiologist or radiographer." Myelination occurs during the first 2 years of life, so an experienced pediatric or radiology image interpreter is also required.

As access to MRI scanners may be limited, it’s important to be ready as soon as a scanner is free, Dr. Rutherford advised. This means that the neonate must be suitably prepared prior to the scan. Choral hydrate, given 15 minutes before the scan, may be used to keep the neonate sedated temporarily, and ear protection must be worn. The neonate’s head and body should then be "wrapped and fixed" as carefully as possibly into position inside the scanner, so there is little chance of any waking or movement during the scan.

Ventilation may be needed during the scan, and a pediatric staff member needs to be with the baby at all times. Pulse oximetry can be used to monitor the neonate while the scan is in progress.

"MRI is an expensive technology, and you really want to make sure that you get the best possible results from all the effort that is put in by trying to put a baby into an MRI scanner," Dr. Rutherford said.

A key element to successful scanning is ensuring that the MRI coil used fits as closely as possibly to the neonate’s head. "Poor coil choice or head positioning results in poor image quality," she warned.

Motion is another common reason for poor quality images, so motion-resistant sequences need to be considered. T1-weighted (transverse/sagittal), T2-weighted (transverse), and diffusion-weighted imaging may all be appropriate sequences to use. Magnetic resonance venography and angiography can provide useful information about thrombosis or stroke, respectively.

"In this day and age, all infants with a neonatal encephalopathy require – and deserve to have – the benefit of an MR scan," Dr. Rutherford said. Other candidates for MRI include neonates with seizures, severe jaundice, abnormal cranial ultrasound findings, unexplained neurologic signs, dysmorphic features, and where a co-twin has died in utero.

Neonates with unexplained symptoms or who are at risk of hemorrhagic/thrombotic lesions require prompt MRI, as soon as access to a scanner can be arranged.

"You will also want to image fairly quickly in cases of severe neonatal encephalopathy, especially if you are considering withdrawing active treatment," Dr. Rutherford said.

By contrast, for acquired injuries, she noted, "If we want to get the best possible detection of any acquired injury, then we should think about imaging probably between 1 and 4 weeks post insult." Diffusion-weighted imaging is best for identifying early ischemic lesions.

With regards to preterm neonates, routine MRI scanning is not recommended, but early scanning is perhaps advisable if there are unexplained symptoms or withdrawal of care is being considered.

Dr. Rutherford is the editor of "MRI of the Neonatal Brain," (Philadelphia: Saunders, Ltd., 2001). More information: MRI of the Neonatal Brain.

LONDON – Magnetic resonance imaging should be used as early as possible to scan the neonatal brain if there are any unexplained symptoms, or if hemorrhagic or thrombotic lesions are suspected.

In the case of thrombosis, it’s important to scan early to decide whether anticoagulation is required, neonatal imaging expert Dr. Mary A. Rutherford of Imperial College London said at the Excellence in Paediatrics annual meeting.

However, Dr. Rutherford, who trained as a pediatrician, noted that for acquired injuries, the use of conventional MRI should be delayed 1-4 weeks, as hypoxic-ischemic brain injury is easier to detect 7 days after the insult.

MRI can be used for a variety of diagnostic and prognostic reasons in full-term neonates; it can help to establish the cause of symptoms, identify brain abnormalities, and determine the likely timing of any injury to the developing brain, she said. Neonatal MRI can also help predict outcomes, provide information for risk management and, in these days of increased medicolegal vigilance, perhaps help clinicians avoid the threat of litigation.

Today, most clinical departments will have an MRI scanner that uses field strengths of 1.5-3 Tesla, which are fine for neonatal imaging, Dr. Rutherford said. "What you really need," she noted, "is an interested radiologist or radiographer." Myelination occurs during the first 2 years of life, so an experienced pediatric or radiology image interpreter is also required.

As access to MRI scanners may be limited, it’s important to be ready as soon as a scanner is free, Dr. Rutherford advised. This means that the neonate must be suitably prepared prior to the scan. Choral hydrate, given 15 minutes before the scan, may be used to keep the neonate sedated temporarily, and ear protection must be worn. The neonate’s head and body should then be "wrapped and fixed" as carefully as possibly into position inside the scanner, so there is little chance of any waking or movement during the scan.

Ventilation may be needed during the scan, and a pediatric staff member needs to be with the baby at all times. Pulse oximetry can be used to monitor the neonate while the scan is in progress.

"MRI is an expensive technology, and you really want to make sure that you get the best possible results from all the effort that is put in by trying to put a baby into an MRI scanner," Dr. Rutherford said.

A key element to successful scanning is ensuring that the MRI coil used fits as closely as possibly to the neonate’s head. "Poor coil choice or head positioning results in poor image quality," she warned.

Motion is another common reason for poor quality images, so motion-resistant sequences need to be considered. T1-weighted (transverse/sagittal), T2-weighted (transverse), and diffusion-weighted imaging may all be appropriate sequences to use. Magnetic resonance venography and angiography can provide useful information about thrombosis or stroke, respectively.

"In this day and age, all infants with a neonatal encephalopathy require – and deserve to have – the benefit of an MR scan," Dr. Rutherford said. Other candidates for MRI include neonates with seizures, severe jaundice, abnormal cranial ultrasound findings, unexplained neurologic signs, dysmorphic features, and where a co-twin has died in utero.

Neonates with unexplained symptoms or who are at risk of hemorrhagic/thrombotic lesions require prompt MRI, as soon as access to a scanner can be arranged.

"You will also want to image fairly quickly in cases of severe neonatal encephalopathy, especially if you are considering withdrawing active treatment," Dr. Rutherford said.

By contrast, for acquired injuries, she noted, "If we want to get the best possible detection of any acquired injury, then we should think about imaging probably between 1 and 4 weeks post insult." Diffusion-weighted imaging is best for identifying early ischemic lesions.

With regards to preterm neonates, routine MRI scanning is not recommended, but early scanning is perhaps advisable if there are unexplained symptoms or withdrawal of care is being considered.

Dr. Rutherford is the editor of "MRI of the Neonatal Brain," (Philadelphia: Saunders, Ltd., 2001). More information: MRI of the Neonatal Brain.