Neonatal cerebral ultrasound: anatomical variants and age-related diseases

Abstract

Cerebral ultrasound is a non-invasive imaging technique widely used for the assessment of brain anatomy and diseases in neonates and infants. Indeed, it allows a precise characterization of common variants such as cavum septum pellucidum or diseases like intraventricular hemorrhage. The aim of this pictorial review is to provide a comprehensive overview of the main ultrasound features of the most common cerebral anatomical variants and disorders detectable by cerebral ultrasound using an age-related approach which could support non-subspecialized radiologists.

Keywords: Anatomical variants; Brain disorders; Cerebral ultrasound; Infants.

Fig. 1

Cerebral ultrasound of 1-day-old premature male born at 32 weeks and 4 days of gestation showed midline fluid-filled cyst between the lateral ventricles on the coronal plane (yellow arrow) consisting in common anatomical variant such as Cavum Septum Pellucidum

Fig. 2

Cerebral ultrasound of 2-day-old full term male showed cavum veli interpositi, appearing as an interhemispheric well-defined unilocular anechoic cyst on mastoid view (blue arrow)

Fig. 3

Screening cerebral ultrasound of a premature female born at 32 weeks and 6 days of gestation showing on sagittal view well-defined anechoic space located in the posterior cranial fossa (yellow asterisk). This finding was suggestive of mega cisterna magna (common anatomical variant)

Fig. 4

Coronal planes of cerebral ultrasound performed on premature infant demonstrated left well-defined cyst (blue arrow in a) and hyperechoic central cleft defining split choroid sign (yellow arrow in b). These are typical findings of choroid plexus cyst

Fig. 5

Cerebral ultrasound of 4-day-old full-term male well demonstrating bilateral multiple-rounded cysts located in the frontal horns of the lateral ventricles on coronal plane (yellow arrows in a) with the typical “string-of-pearls” appearance on sagittal view (yellow arrow in b). These findings are suggestive of connatal cysts

Fig. 6

Premature male infant born at 34 weeks’ gestation who underwent cerebral ultrasound at 2-month old for fever (up to 38.7 °C) and anemia. Coronal plane well showed bilateral hemorrhage in the groove between the thalamus and the nucleus caudate. Grade 1 on the left side and grade 2 on the right side (yellow arrow and red asterisk, respectively)

Fig. 7

Typical findings of germinal matrix hemorrhage of grade 3. Premature male infant born at 34 weeks’ gestation who underwent cerebral ultrasound at 4 days of life showing left subependymal germinal matrix hemorrhage of grade 3 on coronal plane (blue arrow in a). This finding was confirmed on T2 weighted image by MR (yellow asterisk in b). Premature male infant born at 33 weeks and 5 days gestation who underwent cerebral ultrasound at first day of life showing both lateral ventricular hemorrhages and ventriculomegaly on coronal plane (yellow arrows and red asterisk in c, respectively). Magnetic Resonance performed to complete evaluation, confirmed intraventricular and third ventricle hemorrhages on coronal T1 weighted (yellow and blue arrows in d, respectively)

Fig. 8

Follow-up ultrasound of premature male infant born at 34 weeks gestation demonstrated progressive evolution of grade 2 left subependymal germinal matrix hemorrhage. In a intermediate phase of colliquation (yellow arrow in a), followed by subependymal cyst evolution after 2 weeks (red arrow in b)

Fig. 9

Early and late phases evolutions of periventricular leukomalacia of premature infants. a Third-day of life cerebral ultrasound of premature male infant born at 31 weeks and 5 days gestation showed right periventricular white matter hyperechoic areas (yellow arrow), particularly in the right occipital horn. These findings are typical of first 48-h periventricular leukomalacia. Cavum Vergae as anatomical variant is also showed (red asterisk in a). Follow-up radiological imaging of premature female infant born at 33 weeks gestation and birth weight of 1300 g performed three months after first ultrasound examination (not showed). Sagittal ultrasound plane well demonstrated cystic changes of the periventricular white matter (yellow arrow in b). Cystic areas were confirmed on coronal MR T2 weighted, also well demonstrating right ventricular dilatation (yellow arrow and red asterisk in c, respectively). These were typical findings of late-phase evolution of periventricular leukomalacia

Fig. 10

Full term female infant who underwent cerebral ultrasound at 3-days of life for central apneas and epileptic seizures. No cerebral pathological findings were identified on first ultrasound evaluation (not showed), therefore MR was performed at day 4 of life to detect brain anomalies. Right-side acute ischaemia of the temporal lobe and multiple cortical petechiae were detected on DWI (yellow circle and red arrows in a, respectively), which represent typical findings of hypoxic-ischemic encephalopathy. Follow-up cerebral ultrasound showed a corticalfocal hyperechoic area on coronal view as outcome of ischaemia (yellow arrow in b)

Fig. 11

Full term male infant who underwent cerebral ultrasound at second day of life for central apneas and convulsive seizures. No pathological findings were detected on cerebral ultrasound (a). Due to symptoms, MR was also performed, showing an extensive ischaemic lesion in the middle cerebri artery territory on DWI (red asterisk in b). The same patient underwent a follow-up cerebral ultrasound after one week from acute event, well demonstrating a left cortico-subcortical hyperechoic area (yellow arrow in c)

Fig. 12

Full term male infant who underwent cerebral ultrasound at 5 days of life for severe perinatal asphyxia requiring neonatal cardio-vascular reanimation. Coronal ultrasound showed fuzzy periventricular hyperechogenic areas (blue arrows in a). MR performed to complete brain evaluation well demonstrated periventricular ‘comb’ appearance of the deep medullary veins (red arrow in b) and haemorrhagic, punctiform hypointense lesions adjacent to the occipital horns of the lateral ventricles on SWI (yellow arrow in b). These findings were suggestive of deep medullary vein thrombosis

Fig. 13

Full term female who underwent radiological examinations at four day of life for hypothermia. Cerebral ultrasound showed left unilateral thalamic echogenic area on coronal plane (yellow arrow in a). MR well demonstrated left thalamic hemorrhagic stroke on coronal T2w image (yellow arrow in b) associated with linear hypointense area corresponding to thrombosis of thalamic vein (blue arrow in b)

Fig. 14

Four-month old male affected by Haemophilus Influenzae meningitis who underwent cerebral ultrasound showing dilatation of extra-axial spaces and increased vascularization on Doppler (a). MR of the same patient revealed bilateral subarachnoid empyema in the frontal, temporal and parietal areas on coronal T2 weighted (red arrows in b). Bilateral enlargement of supratentorial subarachnoid spaces was also present (yellow asterisk in b). DWI showed bilateral subarachnoid empyema and cortico-subcortical areas of ischaemia (yellow arrows in c)

Fig. 15

Three month-old male infant who underwent cerebral ultrasound for macrocephaly without other clinical symptoms. Coronal plane showed enlarged extra-axial spaces with increased interhemispheric distance (red asterisk). This finding was suggestive of benign external hydrocephalus