Transcranial Doppler and Magnetic Resonance in Tanzanian Children With Sickle Cell Disease

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Background and Purpose—

We determined prevalences of neurological complications, vascular abnormality, and infarction in Tanzanian children with sickle cell disease.

Methods—

Children with sickle cell disease were consecutively enrolled for transcranial Doppler; those with slightly elevated (>150 cm/s), low (<50 cm/s) or absent cerebral blood flow velocity (CBFv) were invited for brain magnetic resonance imaging and magnetic resonance angiography.

Results—

Of 200 children (median age 9; range 6–13 years; 105 [2.5%] boys), 21 (11%) and 15 (8%) had previous seizures and unilateral weakness, respectively. Twenty-eight (14%) had elevated and 39 (20%) had low/absent CBFv, all associated with lower hemoglobin level, but not higher indirect bilirubin level. On multivariable analysis, CBFv>150 cm/s was associated with frequent painful crises and low hemoglobin level. Absent/low CBFv was associated with low hemoglobin level and history of unilateral weakness. In 49 out of 67 children with low/absent/elevated transcranial Doppler undergoing magnetic resonance imaging, 43% had infarction, whereas 24 out of 48 (50%) magnetic resonance angiographies were abnormal. One had hemorrhagic infarction; none had microbleeds. Posterior circulation infarcts occurred in 14%. Of 11 children with previous seizure undergoing magnetic resonance imaging, 10 (91%) had infarction (5 silent) compared with 11 out of 38 (29%) of the remainder (P=0.003). Of 7 children with clinical stroke, 2 had recurrent stroke and 3 died; 4 out of 5 had absent CBFv. Of 193 without stroke, 1 died and 1 had a stroke; both had absent CBFv.

Conclusions—

In one-third of Tanzanian children with sickle cell disease, CBFv is outside the normal range, associated with frequent painful crises and low hemoglobin level, but not hemolysis. Half have abnormal magnetic resonance angiography. African children with sickle cell disease should be evaluated with transcranial Doppler; those with low/absent/elevated CBFv should undergo magnetic resonance imaging/magnetic resonance angiography.

Cerebral perfusion characteristics show differences in younger versus older children with sickle cell anaemia: Results from a multiple-inflow-time arterial spin labelling study

Sickle cell anaemia (SCA) is associated with chronic anaemia and oxygen desaturation, which elevate cerebral blood flow (CBF) and increase the risk of neurocognitive complications. Arterial spin labelling (ASL) provides a methodology for measuring CBF non-invasively; however, ASL techniques using only a single inflow time are not sufficient to fully characterize abnormal haemodynamic behaviour in SCA. This study investigated haemodynamic parameters from a multi-inflow-time ASL acquisition in younger (8-12 years) and older (13-18 years) children with SCA with and without silent cerebral infarction (SCI+/-) (n = 20 and 19 respectively, 6 and 4 SCI+ respectively) and healthy controls (n = 9 and 7 respectively). Compared with controls, CBF was elevated globally in both groups of patients. In the younger SCA patients, blood oxygen content was negatively correlated with CBF in the middle and posterior cerebral artery territories and significantly positively correlated with bolus arrival time (BAT) in the anterior and middle cerebral artery territories. In older children, SCA patients had significantly shorter BAT than healthy controls and there was a significant negative correlation between CBF and oxygen content only in the territory of the posterior cerebral artery, with a trend for a correlation in the anterior cerebral artery but no relationship for the middle cerebral artery territory. In the younger group, SCI+ patients had significantly higher CBF in the posterior cerebral artery territory (SCI+ mean = 92.78 ml/100 g/min; SCI- mean = 72.71 ml/100 g/min; F = 4.28, p = 0.04), but this no longer reached significance when two children with abnormal transcranial Doppler and one with haemoglobin SC disease were excluded, and there were no significant differences between patients with and without SCI in the older children. With age, there appears to be increasing disparity between patients and controls in terms of the relationship between CBF and oxygen content in the anterior circulation, potentially predicting the risk of acute and chronic compromise of brain tissue.

Leigh's disease associated with a dorsal midbrain syndrome

Leigh's disease is a rare progressive neurodegenerative condition caused by a mitochondrial cytopathy. The authors present the case of a 9-year-old girl with dorsal midbrain syndrome causing convergence retraction nystagmus. Magnetic resonance imaging, skin biopsy, and genetic testing confirmed the cause to be Leigh's disease due to two SURF1 mutations. To the authors' knowledge, this is the first reported case of dorsal midbrain syndrome caused by a mitochondrial cytopathy.

The jugular foramen in complex and syndromic craniosynostosis and its relationship to raised intracranial pressure

BACKGROUND AND PURPOSE

Complex and syndromic craniosynostosis can be complicated by raised intracranial pressure (ICP), which in the absence of other identifiable origins, is probably caused by venous hypertension. Children with these conditions have been shown to have narrowing of the sigmoid sinus-jugular vein complex. Evidence of bony narrowing of the jugular foramina in children with complex or syndromic craniosynostosis and raised ICP compared with that in children with craniosynostosis without raised ICP would provide support for the theory that venous hypertension occurs in the former children.

METHODS

Measurements of the jugular foramina were obtained from reformatted helical CT scans obtained in 12 children with complex or syndromic craniosynostosis and raised ICP (group 1) and in two control groups of children with normal ICP. The first control group comprised 10 children with simple nonsyndromic synostosis of one or two sutures (group 2), and the second control group included nine children with complex or syndromic craniosynostosis (group 3).

RESULTS

Children with raised ICP had narrower jugular foramina than did the age-matched control subjects. For group 1, the mean diameter of jugular foramina was 6.5 mm; group 2, 11.5 mm (P <.01); and group 3, 10 mm (P <.05). No significant difference existed between the two control groups.

CONCLUSION

Significantly narrower jugular foramina in children with raised ICP is further evidence of the role of venous outflow obstruction and intracranial venous hypertension in the development of raised ICP in complex and syndromic craniosynostosis.

Measures of folding applied to the development of the human fetal brain

Previous work has suggested the existence of differences between the cerebral cortex of normal individuals, and those of patients with diseases such as epilepsy and schizophrenia. These shape abnormalities may be of developmental origin. Improved shape measures could provide useful tools for neuroscience research and patient diagnosis. We consider the theoretically desirable properties of measures of brain shape. We have implemented seven measures, three from the neuroscience literature, and four new to this field. Three of the measures are zero-order and four are second-order with respect to the surface. We validate the measures using simple geometrical shapes, and a collection of magnetic resonance scans of ten histologically normal ex vivo fetal brains with gestational ages from 19-42 weeks. We then apply the measures to MR scans from two histologically abnormal ex vivo brains. We demonstrate that our implementation of the measures is sensitive to anatomical variability rather than to the discreteness of the image data. All the measures were sensitive to changes in shape during fetal development. Several of the measures could distinguish between the normal and abnormal fetal brains. We propose a multivariate approach to studying the shape of the cerebral cortex, in which both zero-order and second-order measures are used to quantify folding.