Prevalence of "compressed" and asymmetric lateral ventricles in healthy full-term neonates: sonographic study

Post-hemorrhagic ventricular dilatation: inter-observer reliability of ventricular size measurements in extremely preterm infants

BACKGROUND

Post-hemorrhagic ventricular dilatation (PHVD) in preterm infants can be assessed with ventricular size indices from cranial ultrasound. We explored inter-observer reliability of these indices for prediction of severe PHVD.

METHODS

For all 139 infants with IVH, serial neonatal ultrasound at 3 time points (days 4-7, day 14, 36 weeks PMA) were assessed independently by 3 observers with differing levels of training/experience. Ventricular index (VI), anterior horn width (AHW), and fronto-temporal horn ratio (FTHR) were measured and used to diagnose PHVD. For all, inter-observer reliability and predictive values for receipt of surgical intervention were calculated.

RESULTS

Inter-observer reliability for all observers varied from poor to excellent, with higher reliability for VI/AHW (ICC 0.49-0.84/0.51-0.81) than FTHR (0.41-0.82), particularly from the second week. Good-excellent inter-expertise reliability was found between observers with ample experience/training (0.65-0.99), particularly for VI and AHW, while poor-moderate when comparing with an inexperienced observer (0.28-0.88). Slightly higher predictive value for PHVD intervention (n = 12) was found for AHW (AUC 0.86-0.96) than for VI and FTHR (0.80-0.96/0.80-0.95).

CONCLUSIONS

AHW and VI are highly reproducible in experienced hands compared to FTHR, with AHW from the second week onwards being the strongest predictor for receiving surgical intervention for severe PHVD. AHW may aid in early PHVD diagnosis and decision-making on intervention.

IMPACT

While ventricular size indices from serial cUS are superior to clinical signs of increased intracranial pressure to assess PHVD, questions remained on their inter-observer reproducibility and reliability to predict severity of PHVD. AHW and VI are highly reproducible when performed by experienced clinicians. AHW from the second week of birth is the strongest predictor of PHVD onset and severity. AHW, combined with VI, may aid in early PHVD diagnosis and decision-making on need for surgical intervention. Consistent use of these indices has the potential to improve PHVD management and therewith the long-term outcomes in preterm infants.

Hydrocephalus caused by unilateral foramen of Monro obstruction: A review on terminology

Background:

Hydrocephalus caused by unilateral foramen of Monro (FM) obstruction has been referred to in literature by many different terminologies. Precise terminology describing hydrocephalus confined to just one lateral ventricle has a very important prognostic value and determines whether or not the patient can be shunt free after an endoscopic procedure.

Methods:

Aiming to define the best term for unilateral FM obstruction, 19 terms were employed on PubMed database (http://www.ncbi.nlm.nih.gov/pubmed) as quoted phrases.

Results:

A total of 194 articles were found. Four patterns of hydrocephalus were discriminated as a result of our research term query and were divided by types for didactic purpose. Type A - partial dilation of the lateral ventricle; Type B - pure unilateral obstruction of the FM; Type C - previously shunted patients with secondary obstruction of the FM; and Type D - asymmetric lateral ventricles with patent FM.

Conclusion:

In unilateral FM obstruction hydrocephalus, an in-depth review on terminology application is critical to avoid mistakes that may compromise comparisons among different series. This terminology review suggests that Type B hydrocephalus, i.e., the hydrocephalus confined to just one lateral ventricle with no other sites of cerebrospinal fluid circulation blockage, are best described by the terms unilateral hydrocephalus (UH) and monoventricular hydrocephalus, the first being by far the most popular. Type A hydrocephalus is best represented in the literature by the terms uniloculated hydrocephalus and loculated ventricle; Type C hydrocephalus by the terms isolated lateral ventricle and isolated UH; and Type D hydrocephalus by the term asymmetric hydrocephalus.

Neonatal neurosonography

Neonatal neurosonography is used commonly to evaluate the central nervous system in the neonatal intensive care setting. The procedure can be performed at the bedside in these critically ill patients who may suffer from hemodynamic and thermoregulatory instability and often require mechanical ventilation. This article reviews current recommendations regarding neurosonography technique, pathophysiology, and imaging of intracranial insults including hemorrhage, white matter injury, infarction, and hypoxic-ischemic encephalopathy.

New reference values for the neonatal cerebral ventricles

PURPOSE

To establish new cross-sectional reference values for the size of the lateral ventricles in a large cohort of neonates between 24 and 42 weeks' gestational age (GA) as well as longitudinal reference values for the follow-up of very preterm infants born at less than 30 weeks' gestation.

MATERIALS AND METHODS

Institutional review board approval and parental written informed consent were obtained for this prospective cohort study of 625 neonates (58% male patients) with a median GA of 33.4 weeks (range, 24.7-42.6 weeks). All infants underwent cranial ultrasonography (US) within 4 days after birth to evaluate the size of the lateral ventricles. Scanning was repeated in 301 preterm and term neonates within the 1st week of life to assess the presence of ventricular reopening. Seventy-nine very preterm infants (GA, <30 weeks) were prospectively included for cranial US at term-equivalent age (TEA). US measurements were performed of the ventricular index (VI), anterior horn width (AHW), and thalamo-occipital distance (TOD). Statistical analysis was conducted by using a paired t test, multilevel analysis, and analysis of covariance.

RESULTS

Cross-sectional reference values for the VI and TOD increased with maturity, whereas the AHW remained constant. Vaginal birth was independently associated with a slightly smaller AHW following birth and with an increase in AHW within the 1st week of life (P < .05). Preterm-born infants showed a larger ventricular size at TEA compared with term infants (P < .001).

CONCLUSION

New cross-sectional and longitudinal reference curves were established for the size of the neonatal lateral ventricles, which may allow for early identification and quantification of ventriculomegaly due to either posthemorrhagic ventricular dilation or periventricular white matter loss.

State-of-the-art cranial sonography: Part 2, pitfalls and variants

OBJECTIVE

In the first part of this article, modern cranial sonography techniques and interpretation were discussed, emphasizing ways in which the application of modern imaging technology and techniques are able to enhance detection of pathologic abnormalities on cranial sonography.

CONCLUSION

In this part of the article, we will describe pitfalls and variants that may be confused with pathologic abnormalities. Emphasis will be placed on recognizing normal variations and distinguishing them from pathologic abnormalities that may require additional imaging or clinical follow-up.

Cerebral measurements made using cranial ultrasound in term Ugandan newborns

BACKGROUND

Few cUS studies of cerebral measurements are available for normal term infants. Normative data is important for evaluating cerebral structure size in symptomatic term infants and assessing preterm brain growth by term age.

OBJECTIVES

To (i) make linear measurements using cranial ultrasound (cUS) for major cerebral structures and intracranial spaces in normal newborn term infants, (ii) correlate these measurements with gestational age (GA), birth weight (BW), head circumference (HC), gender and within one infant (iii) examine inter/intra-observer variation, and (iv) compare these data with those currently available.

DESIGN, SETTING AND PATIENTS

Linear cUS measurements of major cerebral structures were made in well term-born Ugandan infants at Mulago University Hospital, Kampala. Correlations between the measurements and gender, HC, BW and GA were calculated. Intra- and inter-observer agreements were assessed.

RESULTS

Data from 106 infants (mean GA 39.20±1.4SD weeks) were analysed. Intra/inter-observer agreement was substantial/excellent. Significant correlations were found between HC and pons anterior-posterior diameter (p<0.01), corpus callosal (CC) length (p=0.02) and transverse cerebellar diameter (TCD, p<0.01) and between BW and CC length (p=0.02), vermis height (<0.01) and thalamo-occipital distance (p=0.03); no significant correlation was found with GA. Within infants CC length and TCD correlated significantly (p=0.019). Males had larger left ventricular indices than females (p=0.04). The data was similar to those from other populations.

CONCLUSIONS

These data provide reliable reference values for linear measurements of many cerebral structures made using cUS. The data agree well with those from other populations suggesting that cerebral size is similar in different ethnic groups.

Ultrasound measurements of the lateral ventricles in neonates: why, how and when? A systematic review

Germinal matrix-intraventricular haemorrhage and subsequent post-haemorrhagic ventricular dilatation (PHVD) are frequently encountered complications in preterm neonates. As progressive dilatation of the lateral ventricles may be associated with elevated intracranial pressure, ultrasound measurements of ventricular size play a major role in the evaluation of neonates at risk of ventricular dilatation as well as in assessing the effect of intervention for PHVD. A systematic search was carried out in Medline and Embase to identify neonatal and foetal ultrasound studies on lateral ventricular size. This review presents an overview of the available data concerning neonatal reference values for lateral ventricular size, the influence of gender, ventricular asymmetry and the effect of the mode of delivery on the phenomenon of ventricular reopening following birth.

CONCLUSION

Serial cranial ultrasound measurements of the lateral ventricles play a key role in the early recognition and therapeutic evaluation of post-haemorrhagic ventricular dilation and can be of prognostic value in neonates with ventricular dilatation.

Magnetic resonance imaging characteristics of necrotizing meningoencephalitis in Pug dogs

BACKGROUND

The magnetic resonance imaging (MRI) characteristics of necrotizing meningoencephalitis (NME) are not well documented.

OBJECTIVES

To describe common MRI features of NME, to compare the MRI features to histopathologic findings, and to determine whether or not MRI lesions are predictive of survival time.

ANIMALS

Eighteen Pugs with NME.

METHODS

Retrospective MRI case study of Pugs identified by a search of medical records at 6 veterinary institutions. Eighteen dogs met inclusion criteria of histopathologically confirmed NME and antemortem MRI exam. MRI lesions were characterized and compared with histopathology with the kappa statistic. Survival times were compared with MRI findings by use of Mann-Whitney U-tests and Spearman's rho.

RESULTS

Twelve of 18 lesions were indistinctly marginated with mild parenchymal contrast enhancement. Prosencephalic (17/18) lesion distribution included the parietal (16/18), temporal (16/18), and occipital (16/18) lobes. There were cerebellar (4/18) and brainstem (3/18) lesions. Asymmetric lesions were present in both gray and white matter in all dogs. Falx cerebri shift was common (11/18), and 6 dogs had brain herniation. Leptomeningeal enhancement was present in 9/18 dogs. A moderate positive association was found between parenchymal contrast enhancement and both necrosis (kappa= 0.45; P= .045) and monocytic inflammation (kappa= 0.48; P= .025). Higher MRI lesion burden was correlated with longer time from disease onset to MRI (P= .045). MRI lesion burden did not correlate to survival time.

CONCLUSIONS AND CLINICAL IMPORTANCE

Asymmetric prosencephalic grey and white matter lesions with variable contrast enhancement were consistent MRI changes in Pugs with confirmed NME. While not pathognomonic for NME, these MRI characteristics should increase confidence in a presumptive diagnosis of NME in young Pugs with acute signs of neurologic disease.

Cerebral ventricular size in developing normal kittens measured by ultrasonography

To evaluate the age of fontanelle closure of normal kittens and the size of their lateral ventricles, 50 ultrasonographic examinations using the bregmatic fontanelle as an acoustic window were made. Seven kittens, laboratory animals, were included in the study. To verify the location of the lateral ventricle, two of the kittens were sacrificed as neonates. In one of them ink was injected prior to autopsy into one lateral ventricle under sonographic guidance. In a longitudinal study of five of the kittens, the skull depth and the depth of the central part of the lateral ventricle reproduced in a longitudinal view could be measured up to the age of about 5 months. During that period, the skull depth increased from a median value of 1.95 cm (1.92-1.98) in a seven-day-old cat to 2.58 cm (2.52-2.59) in a 154-day-old cat, while the afore-mentioned ventricle values increased from 0.3 mm to 1.1 mm.

Developmental change of lateral ventricular volume and ratio in Beagle-type dogs up to 7 months of age

Eighteen healthy Beagle-type dogs were studied using magnetic resonance (MR) imaging from a few days after birth up to 7 months of age. We evaluated the onset of lateral ventricular expansion, the developmental change of lateral ventricular volume and the ratio of the largest to the smallest lateral ventricular volume. The onset of lateral ventricular expansion was defined as the day that the expansion by cerebrospinal fluid (CSF) was first visible in unilateral or bilateral lateral ventricles on the transverse images at the level of the intraventricular foramen. It was found that the expansion of lateral ventricles were first detectable at 3-4 weeks. Lateral ventricular volume ratio varied most from the onset of lateral ventricular expansion to 75 days of age and stabilized after that, although absolute brain and lateral ventricular volumes continued to increase.

Computed tomographic findings in full-term infants with good prognosis

To determine the normal neonatal computed tomographic (CT) findings, 121 CT scans of term infants with some neurological symptoms in the neonatal periods and a later good prognosis were studied. The majority of the neonates had asymmetric skulls with backward protrusion of the left occipital bone. In early neonates, the ventricles were small and straight high density lines were commonly seen in the posterior longitudinal cerebral fissure. In many, the left posterior horn was larger than the right one. Periventricular low density areas in the anterior and the posterior horns were noticed. The basal ganglia and the thalamus showed homogeneous density that was the same as that of the cerebellum. About one-third of the neonates had extra-cerebellar low density areas.