Lenticulostriate vasculopathy in twin-to-twin transfusion syndrome

High-resolution neurosonographic examination of the lenticulostriate vessels in neonates with hypoxic-ischemic encephalopathy

OBJECTIVE

To assess the feasibility of visualizing lenticulostriate vessels (LV) using a linear high-resolution ultrasound probe and characterize LV morphology to determine whether morphological alterations in LV are present in neonatal hypoxic-ischemic encephalopathy (HIE) as compared to the unaffected infants.

METHODS

We characterized LV by their echogenicity, width, length, tortuosity, and numbers of visualized stems/branches in neurosonographic examinations of 80 neonates. Our population included 45 unaffected (non-HIE) and 35 with clinical and/or imaging diagnosis of HIE. Of the neonates with clinical diagnosis of HIE, 16 had positive MRI findings for HIE (HIE+MRI) and 19 had negative MRI findings (HIE-MRI). Annotations were performed twice with shuffled data sets at a 1-month interval and intrarater reliability was assessed. Focused comparison was conducted between non-HIE, HIE+MRI and HIE-MRI neonates whose images were acquired with a high frequency linear transducer.

RESULTS

Studies acquired with the two most frequently utilized transducers significantly differed in number of branches (p = 0.002), vessel thickness (p = 0.007) and echogenicity (p = 0.009). Studies acquired with the two transducers also significantly differed in acquisition frequency (p < 0.001), thermal indices (p < 0.001) and use of harmonic imaging (p < 0.001). Groupwise comparison of vessels imaged with the most frequently utilized transducer found significantly fewer branches in HIE + MRI compared to HIE-MRI negative and non-HIE patients (p = 0.005).

CONCLUSION

LV can be visualized in the absence of pathology using modern high-resolution neurosonography. Visualization of LV branches varies between HIE + MRI, HIE-MRI neonates and controls.

ADVANCES IN KNOWLEDGE

High-resolution neurosonography is a feasible technique to assess LV morphology in healthy neonates and neonates with HIE.

Fetal stroke and cerebrovascular disease: Advances in understanding from lenticulostriate and venous imaging, alloimmune thrombocytopaenia and monochorionic twins

Fetal stroke is an important cause of cerebral palsy but is difficult to diagnose unless imaging is undertaken in pregnancies at risk because of known maternal or fetal disorders. Fetal ultrasound or magnetic resonance imaging may show haemorrhage or ischaemic lesions including multicystic encephalomalacia and focal porencephaly. Serial imaging has shown the development of malformations including schizencephaly and polymicrogyra after ischaemic and haemorrhagic stroke. Recognised causes of haemorrhagic fetal stroke include alloimmune and autoimmune thrombocytopaenia, maternal and fetal clotting disorders and trauma but these are relatively rare. It is likely that a significant proportion of periventricular and intraventricular haemorrhages are of venous origin. Recent evidence highlights the importance of arterial endothelial dysfunction, rather than thrombocytopaenia, in the intraparenchymal haemorrhage of alloimmune thrombocytopaenia. In the context of placental anastomoses, monochorionic diamniotic twins are at risk of twin twin transfusion syndrome (TTTS), or partial forms including Twin Oligohydramnios Polyhydramnios Sequence (TOPS), differences in estimated weight (selective Intrauterine growth Retardation; sIUGR), or in fetal haemoglobin (Twin Anaemia Polycythaemia Sequence; TAPS). There is a very wide range of ischaemic and haemorrhagic injury in a focal as well as a global distribution. Acute twin twin transfusion may account for intraventricular haemorrhage in recipients and periventricular leukomalacia in donors but there are additional risk factors for focal embolism and cerebrovascular disease. The recipient has circulatory overload, with effects on systemic and pulmonary circulations which probably lead to systemic and pulmonary hypertension and even right ventricular outflow tract obstruction as well as the polycythaemia which is a risk factor for thrombosis and vasculopathy. The donor is hypovolaemic and has a reticulocytosis in response to the anaemia while maternal hypertension and diabetes may influence stroke risk. Understanding of the mechanisms, including the role of vasculopathy, in well studied conditions such as alloimmune thrombocytopaenia and monochorionic diamniotic twinning may lead to reduction of the burden of antenatally sustained cerebral palsy.

Lenticulostriate vasculopathy in neonates: Is it a marker of cerebral insult? Critical review of the literature

Although lenticulostriate vasculopathy (LSV) was recognized nearly 30 years ago, neonatologists and radiologists still question its clinical significance. The diagnosis of LSV may be highly subjective, resulting in many false negatives when the radiologist is not familiar with the lesion or false positive if over-read by those with special interest in this finding. There has been an increase in incidence of LSV since its recognition in 1985 which might reflect nothing more than a growing awareness of this finding on neonatal cranial ultrasound. On the other hand, improved ultrasound imaging technology may have enhanced identification of LSV. Prospective studies evaluating the presence, significance and diagnosis of LSV are limited and have produced conflicting results. Therefore, the associated risk factors and clinical relevance of LSV on cranial ultrasound remain unclear. This review will examine the existing literature.

The etiology of lenticulostriate vasculopathy and the role of congenital infections

Lenticulostriate vasculopathy (LSV) refers to increased echogenicity of the penetrating vessels that supply the basal ganglia and segments of the internal capsule seen on cranial ultrasound. Initially identified in infants with congenital infection, LSV has now been associated with a variety of infectious and non-infectious conditions. Although robust epidemiologic studies are lacking, the available evidence does not support broad evaluation for multiple congenital infections when LSV is identified. We propose screening infants with LSV for congenital cytomegalovirus infection and ensuring that prenatal screening included appropriate testing for syphilis, human immunodeficiency virus, and rubella-immune status. Large, prospective observational studies are needed to determine the incidence of LSV and the relative contribution of infectious and non-infectious conditions to LSV in the neonate.

Imaging patterns of sonographic lenticulostriate vasculopathy and correlation with clinical and neurodevelopmental outcome

PURPOSE

To evaluate the relationship between the imaging patterns of lenticulostriate vasculopathy (LSV) and clinical outcomes.

METHODS

We performed cranial sonography (US) in 110 neonates and evaluated the patterns of visible lenticulostriate vessels with three grades: 0: no vessel seen; 1 (low grade): one or two thin branches seen; and 2 (high grade): more than three prominent branches seen. Color Doppler US was performed on these vessels to evaluate the presence of flow. Associated underlying diseases and the presence of neurodevelopmental delay on follow-up were reviewed retrospectively.

RESULTS

There were 51 neonates with associated underlying diseases, including congenital heart diseases (CHD) (n = 34) and neonatal hypoxia (n = 13). Sonographic LSV was detected in 29.1% cases (22 low- and 10 high-grade cases). Doppler flow was not detected in three patients with CHD (p = 0.028). CHD (odds ratio [OR], 25.73; p < 0.001), neonatal hypoxia (OR, 7.00; p = 0.020), two underlying diseases (OR, 73.232; p < 0.001), high-grade LSV (OR, 16.29; p = 0.005), and absent color Doppler flow (OR, 40.80; p = 0.046) were significantly associated with neurodevelopmental delay in univariate analysis. In multivariate analysis, underlying diseases and absent color Doppler flow were associated with neurodevelopmental delay. Both high LSV grade (area under the receiver operating characteristic curves of 0.901; 95% confidence interval, 0.823-0.979) and absent color Doppler flow (area under the receiver operating characteristic curves of 0.874; 95% confidence interval, 0.803-0.945) had a high predictive power for neurodevelopmental delay.

CONCLUSIONS

High-grade sonographic LSV and absent color Doppler flow on lenticulostriate vessels were significantly associated with neurodevelopmental delay.

Lenticulostriate vasculopathy in extremely low gestational age newborns: Inter-rater variability of cranial ultrasound readings, antecedents and postnatal characteristics

Although lenticulostriate vasculopathy (LSV) was first detected on a cranial ultrasound nearly 30 years ago, its clinical implications and significance remain unknown. The objective of this study was to evaluate the inter-rater reliability of cranial ultrasound readings of LSV, and to explore relationships with potential antecedents and developmental correlates in extremely low gestational age newborns. Of the 1506 infants enrolled during the years 2002-2004, 1450 had at least one set of ultrasound scans evaluated for LSV and 939 had all three sets. To evaluate the inter-rater agreement for identifying LSV, we compared readings from two independent radiologists on days 1-4, 5-14, and on or after day 15. We then evaluated the relationships between LSV and maternal, antenatal, and postnatal characteristics. Our results showed that kappa values were 0.18, 0.33, and 0.36 on days 1-4, days 5-14, and day 15 or greater. Infants who were identified as LSV positive by two readers had higher Score for Neonatal Acute Physiology-II (an illness severity indicator), higher rates of tracheal infection and bacteremia, lower partial pressure of arterial oxygen and pH levels on 2 of the first 3 postnatal days, and they were more likely to have a lower psycho-motor development index at age 2 years. Positive agreement on the presence of LSV was low, as was the kappa value, an index of inter-rater reliability. Infants with high illness severity scores and their correlates were at increased risk of developing LSV, while those who develop LSV appear to be at increased risk of motor dysfunction.