A pictorial review of the pathophysiology and classification of the magnetic resonance imaging patterns of perinatal term hypoxic ischemic brain injury – What the radiologist needs to know…

Abstract

This article provides a correlation of the pathophysiology and magnetic resonance imaging (MRI) patterns identified on imaging of children with hypoxic ischemic brain injury (HIBI). The purpose of this pictorial review is to empower the reading radiologist with a simplified classification of the patterns of cerebral injury matched to images of patients demonstrating each subtype. A background narrative literature review was undertaken of the regional, continental and international databases looking at specific patterns of cerebral injury related to perinatal HIBI. In addition, a database of MRI studies accumulated over a decade (including a total of 314 studies) was analysed and subclassified into the various patterns of cerebral injury. Selected cases were annotated to highlight the areas involved and for ease of identification of the affected substrate in daily practice.

A proposed magnetic resonance imaging grading system for the spectrum of central neonatal parasagittal hypoxic–ischaemic brain injury

“…with neuroradiological expertise of 15 years and 30 years, respectively. From this database of 297 patients, we classified injuries into the four major patterns of HIBI [ 8 ] as per classification in Table 1 .…”

“…From this database of 297 patients, we classified injuries into the four major patterns of HIBI [ 8 ] as per classification in Table 1 .…”

“…It is not uncommon for radiologists to report these injuries as “mixed patterns” of injury (with suggestion of partial watershed zone involvement in the parasagittal cortex owing to the exaggerated boundaries of the area of encephalomalacia). However, careful examination reveals continuity of the lesions with no intervening normal cerebral substrate, indicating that all the affected structures are contiguously destroyed, most likely due to a common pathophysiological mechanism [ 8 ].…”

“…Neural networks connect these cortical areas with the basal ganglia as well as the thalamus and primary visual cortex, all highly metabolically active areas of the brain in a term neonate, and all demonstrating high N-methyl-D-aspartate (NMDA) receptor expression [ 9 , 10 ]. It is, therefore, highly likely that near-complete injuries to these areas (as in the massive paramedian injury subtype) would be seen in an exaggerated form of profound ischaemia which is severe but also sustained for a more prolonged period of time [ 8 ].…”

Cerebral Palsy and Criteria Implicating Acute Intrapartum Hypoxia in Neonatal Encephalopathy – An Obstetric Perspective for the South African Setting

“…The neuro-radiological magnetic resonance imaging (MRI) terms of 'acute profound' and 'partial prolonged' brain lesions, which have found their way into the medico-legal domain, are often used retrospectively to 'diagnose' and implicate clinical events and scenarios. [23][24][25][26][27] Ideally, the MRI needs to be performed within 21 days of delivery to time the cerebral insult. [28] Timing of the insult becomes more difficult after this period.…”