1. * (p<0.05, Pearson Correlation Coefficient; Compared to MRI)
ҰMeasurements are not made using this view
* (p<0.05, Pearson Correlation Coefficient; Compared to MRI)
ҰMeasurements are not made using this view
Detection of Moderate to Severe Brain Injury in Preterm Infants by adding Mastoid and Posterior Fontanelle
Views to Routine Cranial Ultrasonography compared to Magnetic Resonance Imaging
J Afifi, MM Seshia, RJ Baier, J Wrogemann, M Reed
Departments of Pediatrics and Radiology • University of Manitoba
Introduction
The posterior fossa and cerebellum are poorly visualized using standard cranial ultrasound (cUS). Cerebellar injuries are under-diagnosed in premature infants by standard cUS using anterior fontanelle (AF) approach. cUS imaging adding mastoid fontanelle (MF) and posterior fontanelle (PF) views (extended cUS) may increase the rate of detection of significant brain injury in preterm infants.
Standard cUS Extended cUS
Conventional MRI at term has been reported to be superior to cUS in detecting brain injury and predicting outcome of preterm infants. However, previous studies compared MRI at term to early cUS and used only standard cUS.
Objective
In very preterm infants at term, does extended cUS (compared to standard cUS alone improve detection of moderate to severe brain injury as defined by MRI?
Results
29 infants were studied
9 Infants had moderate-severe brain injury by MRI
Lesion specific comparison between ultrasound and MRI
Standard US
Extended US
Sensitivity 67 78
Specificity 90
NPV 86
PPV 75
Characteristics of Infants studied (n=29)
Gestation (weeks)
27.1± 2.4
Birth weight (grams)
922 ±188
PMA MRI (weeks)
38.7±2.5
PMA cUS (weeks)
39.6± 2.4
MRI 9/29 (31%)
Extended cUS 9/29 (31%)
Standard cUS 8/29 (28%)
Moderate-severe WMI 4 6 8
Grey matter Injury 1
Cerebellar Injury 5
Methods
Prospective study of cUS and MRI at term in preterm infants admitted to NICUs in Winnipeg between May 2011 and February 2013
Inclusion Criteria
Gestational age ≤ 32 weeks
Birth weight ˂ 1250 grams
Exclusion Criteria Major congenital anomalies (CNS anomalies) Chromosomal abnormalities
Independent (blinded) interpretation of US and MRI images by 2 radiologists (1 for US and 1 for MRI)
Definition of moderate to severe brain injury :
Moderate to severe white matter injury (WMI)
Gray matter injury (GMI)
Cerebellar injury (CLI)
Statistical analysis:
Kappa statistic for level of agreement between cUS and MRI detection of moderate-severe brain injury
Extended cUS had better sensitivity, positive and negative predictive values than standard cUS in detecting MRI defined moderate-severe brain injury. Specificity was the same between cUS techniques.
Location of MRI defined Brain Lesions
Conclusions
There is moderate agreement between extended ultrasound and MRI in detection of moderate-severe brain injury
Extended cUS is required for the detection of cerebellar injury by US
Normal extended cUS imaging makes moderate-to- severe brain injury on MRI unlikely
Agreement between ultrasound and MRI
Extended cUS detected all 4 infants with white matter injury and 4/5 infants with cerebellar injury. All 4 cerebellar lesions were detected by extended cUS only and none were detected by standard cUS alone.
Patient
WMI
GMI
Cerebellar Injury 1
Moderate
Normal 2 3 4 5
Mild 6 7 8 9
One infant had grey matter injury and one had cerebellar injury not detected by
cUS (standard and extended).
Injury on MRI
Kappa P
(95%CI)
Normal/Mild Injury
n=20
Moderate-Severe
n=9
Standard US
Normal/Mild 18 3
0.59
0.002
( ) 2 6
Extended US
0.68
<0.001
( ) 7
Aims
To compare detection of MRI defined significant brain injury using standard cUS and extended cUS.
To determine what proportion of infants with normal extended cUS have significant MRI abnormalities.