Age-related variations in white matter anisotropy in school-age children

Background

Determination of diffusion tensor metrics in typically developing school-age children shows that maturational increases in fractional anisotropy (FA) vary across the brain and that age effects on FA are to increases in axial diffusivity in some regions, to decreases in radial diffusivity in some, and to both increases in axial and decreases in radial diffusivity in others.

Objective

When studying developing white matter (WM) using diffusion tensor imaging (DTI), knowledge of age-related normative tensor metrics is important, as normal variations can mask or mimic disease effects.

Materials and methods

Right-handed English-speaking children (n?=?32) 6–18 years old (mean 11.0) were studied over 31 months, 7 longitudinally. Anisotropy data were analyzed using tract-based spatial statistics; 43 regions showing significant (P?<?0.05) age effects on fractional anisotropy (FA) were analyzed for age effects (r), coefficient of variability (CV), and FA, axial and radial diffusivity. This study was IRB-approved.

Results

The callosal genu and splenium showed the highest FA values, smallest age effects, and lowest between-subject variability. Mean FA was lower and age effects were greatest in the dorsal callosal body. The highest age effects on FA were in the cingulum, centrum semiovale, right corticospinal tract, and right temporal WM. The dorsal callosal body, calcarine WM, superior frontal and temporal gyri, and right corticospinal tract showed the highest CV. Radial diffusivity decreased while axial diffusivity increased in the cingulum, decreased in the optic tracts, and showed minimal or no age effects in most other regions.

Conclusion

Age effects on FA and variability in FA are location-dependant in developing WM.     

Radiologic differences in white matter maturation between preterm and full-term infants: TBSS study

Background

Widespread white matter (WM) pathology in preterm children has been proposed.

Objective

The purpose of this study was to investigate maturational differences of WM between preterm infants with thinning of the corpus callosum and full-term infants.

Materials and methods

A total of 18 preterm children and 18 full-term children were divided into three subgroups according to the corrected age at the time of diffusion tensor imaging scanning. Tract-based spatial statistics was used for assessing differences in fractional anisotropy (FA) between preterm and full-term children, and between each age-related subgroup in preterm and in full-term children.

Results

In the preterm group, FA values of overall WM showed an increase with age. This trend indicates that WM maturation is a gradual occurrence during a child’s first 2 years. In the full-term group, most WM structures had reached maturation at around 1 year of age; however, centrum semiovale level showed sustained maturation during the first 2 years.

Conclusion

Results of our study demonstrate radiologic maturational differences of WM and provide evidence of the need for therapeutic intervention within 2 years of birth to prevent specific functional impairment and to improve clinical outcome in preterm children.     

Effect of antenatal growth and prematurity on brain white matter: diffusion tensor study

Background

White matter maturation is characterised by increasing fractional anisotropy (FA) and decreasing mean diffusivity (MD). Contradictory results have been published on the effect of premature birth on white matter maturation at term-equivalent age.

Objective

To assess the association of gestational age and low birth-weight-for-gestational-age (z-score) with white matter maturation.

Materials and methods

Infants (n?=?76, 53 males) born at different gestational ages were imaged at term-equivalent age. Gestational age and birth weight z-score were used as continuous variables and the effect on diffusion parameters was assessed. Brain maturation was studied using regions-of-interest analysis in several white matter areas.

Results

Gestational age showed no significant effect on white matter maturation at term-equivalent age. Children with low birth weight z-score had lower FA in the genu and splenium of the corpus callosum (regression, P?=?0.012 and P?=?0.032; correlation, P?=?0.009 and P?=?0.006, respectively), and higher MD in the splenium of the corpus callosum (regression, P?=?0.002; correlation, P?=?0.0004) compared to children whose birth weight was appropriate for gestational age.

Conclusion

Children with low birth weight relative to gestational age show delay and/or anomaly in white matter maturation at term-equivalent age.     

Prognostic value of gradient echo T2* sequences for brain MR imaging in preterm infants

Background

Gradient echo T2*-W sequences are more sensitive than T2-W spin-echo sequences for detecting hemorrhages in the brain.

Objective

The aim of this study is to correlate presence of hemosiderin deposits in the brain of very preterm infants (gestational age <32 weeks) detected by T2*-W gradient echo MRI to white matter injury and neurodevelopmental outcome at 2 years.

Materials and methods

In 101 preterm infants, presence and location of hemosiderin were assessed on T2*-W gradient echo MRI performed around term-equivalent age (range: 40–60 weeks). White matter injury was defined as the presence of >6 non-hemorrhagic punctate white matter lesions (PWML), cysts and/or ventricular dilatation. Six infants with post-hemorrhagic ventricular dilatation detected by US in the neonatal period were excluded. Infants were seen for follow-up at 2 years. Univariate and regression analysis assessed the relation between presence and location of hemosiderin, white matter injury and neurodevelopmental outcome.

Results

In 38/95 (40%) of the infants, hemosiderin was detected. Twenty percent (19/95) of the infants were lost to follow-up. There was a correlation between hemosiderin in the ventricular wall with >6 PWML (P?<?0.001) and cysts (P?<?0.001) at term-equivalent age, and with a lower psychomotor development index (PDI) (P=0.02) at 2 years. After correcting for known confounders (gestational age, gender, intrauterine growth retardation and white matter injury), the correlation with PDI was no longer significant.

Conclusion

The clinical importance of detecting small hemosiderin deposits is limited as there is no independent association with neurodevelopmental outcome.     

Melamine-induced urinary calculi in infants—sonographic manifestations and outcomes 1 year after exposure

Background

In 2008, the melamine-tainted-milk incident started with reports of increased incidence of urolithiasis in infants in China. Affected children were screened for urolithiasis.

Objective

The purpose of this study was to analyze sonographic characterization of infant melamine-induced urolithiasis.

Materials and methods

Transabdominal US examination was done in 603 infants with melamine-induced calculi. The imaging characteristics of calculi and hydronephrosis were analyzed. Follow-up US imaging was performed.

Results

Comet-tail sign was seen behind the calculus of <4 mm. Calculi of ≥4 mm were found in 299 inpatients with clear posterior border and with or without light shadowing. Solitary and multiple stones had similar incidence. Incidence of calculi in the inferior renal calyx was the highest (55.2%) in inpatients. Calculus size in inpatients age 2–3 years was smaller than that of children younger than 2 years old (P?<?0.05). Inpatients age 2–3 years had the highest incidence rate (48.0%) of hydronephrosis.

Conclusion

Calculi of <4 mm manifested as hyperechoic foci near the renal papillae, while calculi of ≥4 mm usually manifested as echogenic foci with visible inferior edge in the renal calyx. Hydronephrosis was a common imaging finding in inpatients ages 2–3 years.     

Computed tomography measurements of the normal and the pathologic cochlea in children

Background

Radiological investigation is frequently undertaken to assess the aetiology of sensorineural hearing loss (SNHL).

Objective

To establish the CT measurements of the normal cochlea in children and to determine radiological criteria correlated with SNHL.

Materials and methods

A retrospective study of temporal bone CT performed in 159 children, age range from 3 days to 16 years between February 1999 and July 2004. A control group (n?=?88) comprised children without SNHL; the SNHL group comprised 71 children. The width of the second turn of the cochlea (CW), the cochlear height (CH), and the width of the bony canal for the cochlear nerve (WCN) were measured on a reference plane containing the modiolus, the posterior semicircular canal, the footplate, and the stapes arch.

Results

Width of the canal measurements ≤1.7 mm or ≥2.5 mm supported the diagnosis of SNHL with a specificity of 97% and 91%, respectively. Cochlear width was found to be significantly smaller in the SNHL group (5.61?±?0.51 mm) than in the control group (5.75?±?0.31 mm, P?<?0.02), a size <5.4 mm being highly suggestive of SNHL with a specificity of 90%. No significant variations of all measurements were found with age.

Conclusion

Appropriate measurements of WCN and CW are highly correlated with SNHL.     

White matter integrity on fractional anisotropy maps in encephalopathic neonates post hypothermia therapy with normal-appearing MR imaging

Background

Neonatal encephalopathy (NE) is a clinically defined neurological syndrome commonly caused by ischemia.

Objective

We investigated white matter integrity in children with NE using diffusion tensor imaging (DTI) and examined the hypothesis that white matter insults not visible on conventional MRI may have abnormal fractional anisotropy (FA) on DTI.

Materials and methods

DTI was performed on 36 term encephalopathic neonates who had hypothermia therapy. Of these, 12 neonates had normal conventional MRI findings (NNE) and 24 neonates had abnormal MRI findings (ANE). Twelve term-equivalent premature neonates with normal clinical neuroimaging and neurological function served as the control group.

Results

We found significant reductions in measured FA in white matter in the ANE neonates compared to the control group. There were, however, no significant differences in measured FA in white matter between the NNE and the control group.

Conclusion

We did not find white matter changes detectable by DTI in encephalopathic neonates post hypothermia with normal conventional MRI findings. Further studies would be required to determine whether this unexpected finding is a direct result of neuroprotective effects of hypothermia, or more sophisticated measures of FA are required to detect subtle white matter injury.     

Incidental pineal cysts in children who undergo 3-T MRI

Background

Pineal cysts, both simple and complex, are commonly encountered in children. More cysts are being detected with MR technology; however, nearly all pineal cysts are benign and require no follow-up.

Objective

To discover the prevalence of pineal cysts in children at our institution who have undergone high-resolution 3-T MRI.

Materials and methods

We retrospectively reviewed 100 consecutive 3-T brain MRIs in children ages 1 month to 17 years (mean 6.8 ± 5.1 years). We evaluated 3-D volumetric T1-W imaging, axial T2-W imaging, axial T2-W FLAIR (fluid attenuated inversion recovery) and coronal STIR (short tau inversion recovery) sequences. Pineal parenchymal and cyst volumes were measured in three planes. Cysts were analyzed for the presence and degree of complexity.

Results

Pineal cysts were present in 57% of children, with a mean maximum linear dimension of 4.2 mm (range 1.5–16 mm). Of these cysts, 24.6% showed thin septations or fluid levels reflecting complexity. None of the cysts demonstrated complete T2/FLAIR signal suppression. No cyst wall thickening or nodularity was present. There was no significant difference between the ages of children with and without cysts. Cysts were more commonly encountered in girls than boys (67% vs. 52%; P?=?0.043). There was a slight trend toward increasing pineal gland volume with age.

Conclusion

Pineal cysts are often present in children and can be incidentally detected by 3-T MRI. Characteristic-appearing pineal cysts in children are benign, incidental findings, for which follow-up is not required if there are no referable symptoms or excessive size.     

Ganglion cysts in the paediatric wrist: magnetic resonance imaging findings

Background

The majority of published literature on ganglion cysts in children has been from a surgical perspective, with no dedicated radiologic study yet performed.

Objective

Our aim was to assess the magnetic resonance (MR) imaging appearance of ganglion cysts in a series of paediatric MR wrist examinations.

Materials and methods

Ninety-seven consecutive paediatric MR wrist examinations were retrospectively reviewed for the presence of ganglion cysts. Only those studies with wrist ganglia were included. Cysts were assessed for location, size, internal characteristics and secondary effect(s).

Results

Forty-one ganglion cysts (2–32 mm in size) were seen in 35/97 (36%) patients (24 female, 11 male), mean age: 13 years 11 months (range: 6 years 3 months-18 years). The majority were palmar (63.4%) with the remainder dorsal. Of the cysts, 43.9% were related to a wrist ligament(s), 36.6% to a joint and 17.1% to the triangular fibrocartilage complex. Of the patients, 91.4% had wrist symptoms: pain (n=29, 82.9%), swelling (n=7, 20%) and/or palpable mass (n=4, 11.4%); 71.4% patients had significant additional wrist abnormalities.

Conclusion

Ganglion cysts were frequently found in children referred for wrist MRI.     

Acoustic radiation force impulse imaging—normal values of liver stiffness in healthy children

Background

Acoustic radiation force impulse imaging (ARFI) is a recent ultrasound technique to assess tissue stiffness.

Objective

Our aim was to describe the feasibility and to define normal ARFI values in liver in children.

Materials and methods

ARFI values were measured in 103 children (ages 2 weeks to 17 years) divided into four age groups, at a minimum depth of 3 cm. In 20 children, measurements were done at 3-, 4- and 5-cm depth in the liver to assess the suitability of measurement location. The impact of age groups and of depth groups was examined using multilevel models. The precision of the measurements was determined using intraclass correlation coefficient (ICC).

Results

There was no statistical difference between measurements taken at different ages, with a mean propagation velocity of 1.12 m/s (range: 0.73 to 1.45 m/s). There was no significant difference according to the depth of the regions of interest (up to 5 cm). The ICC was 0.77 (95% CI 0.69–0.83).

Conclusion

ARFI is feasible in children at any age with an acceptable reliability. The depth of measurements in the liver seems to have no influence on test results. We set the standard ARFI elastography values for healthy liver in children.     

Laparoscopic resection of adrenal neuroblastoma without image-defined risk factors: a prospective study on 21 consecutive pediatric patients

Background

Over the last 20 years MIS has progressively gained popularity in children with cancer. We therefore aimed at evaluating the safety of Minimally Invasive Surgery (MIS) resection in a series of children affected by adrenal neuroblastoma (NB) presenting without Image-Defined Risk Factors (IDRFs).

Methods

An Institutional protocol for MIS resection of adrenal NB in pediatric patients without IDRFs has been applied since 2008. Absence of IDRFs represented the main indication for MIS in NB, regardless of tumor size. All pediatric patients who underwent MIS for NB between January 2008 and May 2013 were included. Specific technical considerations, demographic data, and outcome have been recorded.

Results

Twenty-one patients underwent MIS resection for IDRFs-negative adrenal NB. Nine of these patients experienced preoperative downgrading of IDRFs after chemotherapy. Radiological median diameter of the mass was 30 mm (range 10–83 mm). Median operative time was 90 min. Median hospital stay was 4 days. All patients were treated successfully, without serious intraoperative complications. One mild intraoperative hemorrhage occurred and was treated without the need for conversion to open surgery nor blood transfusion was required. No postoperative complications, including port-site or peritoneal metastases were experienced.

Conclusions

This study demonstrated the safety and effectiveness of MIS for the resection of adrenal NB without IDRFs in children. Pediatric surgeons dedicated to oncology should be aware of this alternative approach to open resection.     

Effect of antenatal growth on brain white matter maturation in preterm infants at term using tract-based spatial statistics

Background

White matter maturation of infants can be studied using diffusion tensor imaging (DTI). DTI of the white matter of the infant brain provides the best available clinical measures of brain tissue organisation and integrity.

Objective

The purpose of this study was to compare white matter maturation between preterm infants born small for gestational age (SGA) and preterms with weight appropriate for gestational age (AGA) at birth.

Materials and methods

A total of 36 preterm infants were enrolled in the study (SGA, n?=?9). A rater-independent method called tract-based spatial statistics (TBSS) was used to assess white matter maturation.

Results

When measured by TBSS, the AGA infants showed higher fractional anisotrophy values in several white matter tracts than the SGA infants. Areas with significant differences included anterior thalamic radiation, corticospinal tract, forceps major and minor, inferior fronto-occipital fasciculus, inferior longitudinal fasciculus, superior longitudinal fasciculus, uncinate fasciculus, and superior longitudinal fasciculus (temporal part). No significant difference was found for mean diffusivity.

Conclusion

As an objective and user-independent method, TBSS confirmed that preterm infants with impaired antenatal growth have impaired white matter maturation compared to preterm infants with normal antenatal growth. The differences were mainly detected in radiations that are myelinated first.     

Validation of automatic bone age determination in children with congenital adrenal hyperplasia

Background

Determination of bone age is routinely used for following up substitution therapy in congenital adrenal hyperplasia (CAH) but today is a procedure with significant subjectivity.

Objective

The aim was to test the performance of automatic bone age rating by the BoneXpert software package in all radiographs of children with CAH seen at our clinic from 1975 to 2006.

Materials and methods

Eight hundred and ninety-two left-hand radiographs from 100 children aged 0 to 17 years were presented to a human rater and BoneXpert for bone age rating. Images where ratings differed by more than 1.5 years were each rerated by four human raters.

Results

Rerating was necessary in 20 images and the rerating result was closer to the BoneXpert result than to the original manual rating in 18/20 (90 %). Bone age rating precision based on the smoothness of longitudinal curves comprising a total of 327 data triplets spanning less than 1.7 years showed BoneXpert to be more precise (P<0.001).

Conclusion

BoneXpert performs reliable bone age ratings in children with CAH.     

The long-term effect of erythropoiesis stimulating agents given to preterm infants: a proton magnetic resonance spectroscopy study on neurometabolites in early childhood

Background

Erythropoiesis stimulating agents (ESAs) are neuroprotective in cell and animal models of preterm birth. Prematurity has been shown to alter neurometabolite levels in children in studies using proton magnetic resonance spectroscopy (1H-MRS).

Objective

We hypothesized that ESA treatment in premature infants would tend to normalize neurometabolites by 4–6 years of age.

Materials and methods

Children in a longitudinal study of neurodevelopment underwent MRI and 1H-MRS at approximately 4 years and 6 years of age. Prematurely born children (500–1,250 g birth weight) received ESAs (erythropoietin or darbepoetin) or placebo during their neonatal hospitalization, and these groups were compared to healthy term controls. 1H-MRS spectra were obtained from the anterior cingulate (gray matter) and frontal lobe white matter, assessing combined N-acetylaspartate and N-acetylaspartylglutamate (tNAA), myo-inositol, choline compounds (Cho), combined creatine and phosphocreatine, and combined glutamate and glutamine.

Results

No significant (P≤0.5) group differences were observed for any metabolite level. Significant age-related increases in white-matter tNAA and Cho were observed, as well as a trend for increased gray-matter tNAA.

Conclusion

Neither prematurity nor neonatal ESA treatment was associated with differences in brain metabolite levels in the children of this study at a significance level of 0.05. These findings suggest that earlier differences that might have existed had normalized by 4–6 years of age or were too small to be statistically significant in the current sample.

     

Lung tattooing combined with immediate video-assisted thoracoscopic resection (IVATR) as a single procedure in a hybrid room: our institutional experience in a pediatric population

Background

Analysis of small pulmonary nodules in children poses an important diagnostic and therapeutic challenge for clinicians.

Objective

To review our experience of lung tattooing with immediate video-assisted thoracoscopic resection (IVATR) performed as a single procedure in a hybrid room for technical difficulties, complications and diagnostic yield of the procedure.

Material and methods

Retrospective analysis of 31 children (16 boys, 15 girls) who underwent lung tattooing of various lesions from January 2001 to July 2011. Data were collected from the Interventional Radiology database, Electronic Patient Chart (EPC) and PACS.

Results

A total of 34 lesions were treated in 31 children. Tattooing was performed on lung lesions with median size 3 mm and median depth 2 mm from pleura. Technical success was 91.1% and diagnostic yield was 100%. In seven children, it was combined with other interventional radiologic procedures. The median procedure time for lung tattooing and IVATR was 197 min.

Conclusion

Lung tattooing with IVATR as a single procedure in a hybrid room is safe and effective in children with several inherent advantages, including avoiding the need to move the child from the interventional radiology suite to the operating room.     

Evaluation of carotid intima-media thickness, a marker of subclinical atherosclerosis, in children with cerebral palsy

Background

Respiratory and cardiovascular diseases are the most common causes of death in children with cerebral palsy.

Objective

To evaluate sonographic carotid intima-media thickness, an early marker of atherosclerosis, in children with cerebral palsy and in healthy controls.

Materials and methods

One hundred children with cerebral palsy (65 boys), mean age 6.2 (SD, 2.1) years, and 35 age-matched and sex-matched healthy controls were included. Common carotid artery intima-media thickness was measured sonographically. Differences between patients and controls were evaluated with an independent samples t-test.

Results

Age, sex distribution and levels of serum lipids were comparable between patients and controls. Average, right and left carotid artery intima-media were thicker in patients compared with controls (mean ± SD, 0.61?±?0.13 mm vs 0.40?±?0.03 mm; 0.61?±?0.14 mm vs 0.40?±?0.03 mm; 0.61?±?0.13 mm vs 0.40?±?0.03 mm, respectively; all P?Conclusion Carotid intima-media is sonographically thicker in children with cerebral palsy compared with healthy controls, which may express an increased risk of atherosclerotic diseases.     

Self-reported assessment of health-related quality of life in children who underwent restorative proctocolectomy with ileal J-pouch anal anastomosis for ulcerative colitis

Purpose

To clarify health-related quality of life (HRQOL) by self-evaluation after restorative proctocolectomy with ileal J-pouch anal anastomosis (IPAA) in children with ulcerative colitis, a questionnaire using the Pediatric Quality of Life Inventory? 4.0 (PedsQL) was administered.

Methods

The PedsQL was administered to 13 consecutive children (mean age 14.5 years) who underwent IPAA between 2005 and 2010 in our hospital and age-matched healthy controls. The mean duration after IPAA was 2.5 years (range 0.08–6 years) at the time of this study. Healthy children completed the same questionnaire by retrospective imaging during the past 1 month by the PedsQL evaluation policy.

Results

Patients’ total score and each functioning score after IPAA reached the same levels as those in healthy controls. Soiling, pouchitis occurrence, and bowel movements had no significant relationship to the PedsQL total score and each functioning score.

Conclusions

Interference of physical activity, emotional status, and social life caused by refractory ulcerative colitis (UC) worsens patients’ HRQOL. IPAA could resolve these problems in children with UC and result in an HRQOL comparable with that in healthy children.     

Does Staphylococcus aureus nasal carriage require eradication prior to elective ambulatory surgery in children?

Purpose

Rates of community-associated Staphylococcus aureus, and particularly of methicillin-resistant Staphylococcus aureus (MRSA) in children, have increased in recent years. We investigated rates of nasal colonization of S. aureus, and a possible correlation between nasal carriage and wound infection.

Methods

A prospective study of children scheduled for elective day-care surgical procedures between January 2008 and December 2012 at one medical center. Nasal swabs were taken before surgery, and follow-up was performed 1–2 weeks following surgery.

Results

Of 1,127 children (median age 2 years, 70.6 % males), positive nasal swabs were detected in 228 (20.2 %). Rates of S. aureus nasal carriage were lowest for ages 6 months to 2 years and highest for ages 4–11 years. Child’s sex did not associate with the risk for positive nasal swabs. Positive nasal swabs for MRSA were detected in five boys (0.62 % of the population). Five children (0.44 %) had wound infection. None of them was a nasal carrier.

Conclusions

No correlation was observed between positive nasal swabs and wound infection in children who were candidates for elective ambulatory operations. This suggests that evaluation of S. aureus nasal carriage and eradication may not be necessary in this population.     

Predictors of mortality in children with typhoid ileal perforation in a Nigerian tertiary hospital

Purpose

Childhood typhoid ileal perforation is associated with high morbidity and mortality. Our aim was to ascertain the predictors of survival in children.

Materials and methods

This is a tertiary hospital-based retrospective review of patients aged ≤15 years managed for typhoid ileal perforations between January 2005 and December 2013. The details of their biodata, potential risk factors and outcome were evaluated.

Results

Forty-five children out of a total of 97 with typhoid fever had typhoid ileal perforation. The age range was 2–15 years, mean (±SD) = 9.3 (±3.31) years, median = 10 years. There were more males than females (26:19). Thirty-nine (86.7 %) patients were >5 years old. There were nine deaths (20 % mortality). The mean (±SD) age of survivors was 9.8 (±2.9) years and 7.1 (±4.2) for non-survivors (p = 0.026). The duration of illness at presentation, gender, admission temperature, nutritional status and packed cell volume, perforation-operation interval, number of perforations, surgical procedure, and the duration of surgery did not statistically influence survival (p > 0.05). The age of the patients and burst abdomen attained statistical significance (p < 0.05).

Conclusion

The patients’ age and postoperative burst abdomen were significant determinants of survival in children with typhoid ileal perforation.