MRI More Sensitive, Specific Than Ultrasound in Diagnosing Fetal Stroke
Out of 34 cases of MRI-detected fetal stroke, ultrasound was only able to identify 5 cases.
VANCOUVER – Magnetic resonance imaging (MRI) has superior sensitivity and specificity for the diagnosis of fetal stroke, compared to ultrasonography, according to study results presented at the 2016 Child Neurology Society Annual Meeting in Vancouver, British Columbia, October 26-29, 2016.
Despite its strong association with morbidity and mortality, little research has been done comparing the diagnostic value of MRI vs the more accessible ultrasound in fetal stroke.
In this study, researchers led by Aleksandra Korostyshevskaya, of the Institute International Tomography Center of the Russian Academy of Sciences, conducted a retrospective review of 207 cases that underwent fetal MRI at 1.5 Tesla and ultrasonography for a range of indications (mean gestation age= 25 weeks [15-38 weeks]). In all cases, MRI was conducted within 1 week of ultrasound.
Fetal MRI detected 22 cases of hemorrhagic stroke, 5 cases of subacute ischemic stroke, and 7 cases of chronic ischemic stroke, compared to ultrasonography, which correctly identified 3 cases of severe hemorrhagic stroke and 2 cases of chronic ischemic stroke.
Analysis of MRI scans allowed researchers to determine hemorrhagic severity, with 50% of cases graded by researchers as first degree, 25% as second degree, and 25% as third degree severity.
Diagnostic performance of ultrasonography was measured at 15.6% sensitivity, 98.3% specificity, 62.5% true positive value, and 13.6% true negative value.
Ultimately, diagnosis of fetal stroke with ultrasonography is plagued by low sensitivity and false-negatives, suggesting that fetal MRI should be standard in cases of suspected fetal stroke. However, limited availability of fetal MRI may contribute to the underestimation of fetal stroke prevalence.
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Korostyshevskaya A, Savelov A, Makogon A, Yarnykh V. Diagnosis of Prenatal Stroke: The Value of Fetal Ultrasonography and MRI. Presented at: 2016 Child Neurology Society Annual Meeting. October 26-29, 2016; Vancouver, BC. Abstract 86.