Normal volumetric and T1 relaxation time values at 1.5 T in segmented pediatric brain MRI using a MP2RAGE acquisition.

OBJECTIVES: This study introduced a tailored MP2RAGE-based brain acquisition for a comprehensive assessment of the normal maturing brain. METHODS: Seventy normal patients (35 girls and 35 boys) from 1 to 16 years of age were recruited within a prospective monocentric study conducted from a single University Hospital. Brain MRI examinations were performed at 1.5 T using a 20-channel head coil and an optimized 3D MP2RAGE sequence with a total acquisition time of 6:36 min. Automated 38 region segmentation was performed using the MorphoBox (template registration, bias field correction, brain extraction, and tissue classification) which underwent a major adaptation of three age-group T1-weighted templates. Volumetry and T1 relaxometry reference ranges were established using a logarithmic model and a modified Gompertz growth respectively. RESULTS: Detailed automated brain segmentation and T1 mapping were successful in all patients. Using these data, an age-dependent model of normal brain maturation with respect to changes in volume and T1 relaxometry was established. After an initial rapid increase until 24 months of life, the total intracranial volume was found to converge towards 1400 mL during adolescence. The expected volumes of white matter (WM) and cortical gray matter (GM) showed a similar trend with age. After an initial major decrease, T1 relaxation times were observed to decrease progressively in all brain structures. The T1 drop in the first year of life was more pronounced in WM (from 1000-1100 to 650-700 ms) than in GM structures. CONCLUSION: The 3D MP2RAGE sequence allowed to establish brain volume and T1 relaxation time normative ranges in pediatrics. KEY POINTS: • The 3D MP2RAGE sequence provided a reliable quantitative assessment of brain volumes and T1 relaxation times during childhood. • An age-dependent model of normal brain maturation was established. • The normative ranges enable an objective comparison to a normal cohort, which can be useful to further understand, describe, and identify neurodevelopmental disorders in children.

Improving diagnosis accuracy of brain volume abnormalities during childhood with an automated MP2RAGE-based MRI brain segmentation.

BACKGROUND AND PURPOSE: It can be challenging to depict brain volume abnormalities in the pediatric population on magnetic resonance imaging (MRI). The aim of the study was to evaluate the inter-radiologist reliability in brain MRI interpretation, including brain volume assessment and the efficiency of an automated brain segmentation. MATERIALS AND METHODS: We performed a single-center prospective study including 44 patients aged six months to five years recruited from the University Hospital, having a 1.5T brain MRI using a MP2RAGE sequence. All MRI were randomly and blindly reviewed by one junior and two senior pediatric radiologists. Inter-observer agreements were assessed using Fleiss' kappa coefficient. Brain volumetry (total intracranial volume (TIV), brain parenchyma, and cerebrospinal fluid volumes) was estimated using the MorphoBox prototype. Clinical head circumference (HC) and z scores were reported. A Pearson correlation coefficient was calculated between brain volumes with HC. RESULTS: Twenty-four brain MRI examinations were normal and twenty were pathological. Brain volume abnormalities were poorly detected by junior and senior radiologists: sensitivities 16.67% [confidence interval 4.7-44.8], 33.33% [13-60] and 30.7% [12-58] and specificities 93.75% [79-98], 84.38% [68-93] and 77% [60-88], respectively. Brain volume apart, interobserver kappa coefficients were 0.93 between junior and seniors as well as between seniors. Brain volumes were significantly correlated with HC (P<0.0001). In patients with normal MRI, brain parenchyma volumes increased regularly with age. Low brain volume was easier to identify with automated quantification. CONCLUSION: Brain volume was poorly appreciated by radiologists. The fully automated brain segmentation used can provide quantitative data to better diagnose, describe, and follow-up brain volume abnormalities.

Impact on child and parent anxiety level of a teddy bear-scale mock magnetic resonance scanner.

BACKGROUND: Pediatric magnetic resonance imaging (MRI) can be stressful. Mock MR scanners have been proven to be effective in avoiding the use of general anesthesia. OBJECTIVES: We prospectively evaluated the impact of a teddy bear-scale model of a mock MR scanner on the anxiety experienced by parents and their children during MRI without general anesthesia . MATERIALS AND METHODS: A 1-year prospective study before and after the installation of a mock scanner in a Pediatric Radiology Department of a university hospital. Anxiety levels were self-estimated by children ages 4 to 16 years and by the parents with a visual analogue scale (from 0, completely relaxed, to 100, extremely stressed) at three moments: in the waiting room, in the preparation room after an explanation by the MRI technologists, and at the issue of the MR acquisition images. Two groups were tested: one with a mock MR scanner, the other without. Analysis of variance (ANOVA) and Fisher exact tests were performed. Motion artifacts were studied. RESULTS: Ninety-one children and their parents were included. The median age was 8 years (standard deviation [SD]=2). In the post mock period, the ambiance of the preparation room was considered by children as significantly more relaxing in 50% vs. 20% (P=0.004) and the anxiety level of children was significantly lower after the explanation, particularly in girls, but unchanged for their parents. The anxiety levels at the end of the examination were significantly lower for parents. The motion artifacts rate was lower (1.7% vs. 4.7%, P=0.04). CONCLUSION: A mock scanner was an efficient tool to improve efficiency of the explanation and to decrease anxiety in children and motion artifacts in pediatric MRI.

Can We Reduce Frame Rate to 15 Images per Second in Pediatric Videofluoroscopic Swallow Studies?

Videofluoroscopic Swallow studies (VFSS) are useful radiological examinations to explore swallowing disorders but which require ionizing radiation. The aim of our study was to evaluate the comparability of pediatric VFSS at 15 frames per second (fps) with 30 fps. Fifty-five loops including 190 swallowings of VFSS at 30 fps performed on 32 consecutive pediatric patients in a University Hospital Center were retrospectively modified by a software to delete one image out of two to obtain secondary loops with a frame rate of 15 fps. An otorhinolaryngologist-phonatrician and a radiologist reviewed all swallowings blindly and randomly using the penetration and aspiration scale (PAS). In case of discordance, they concluded a consensual interpretation. Fifteen girls and seventeen boys were included. The median age was 4 years and 8 months (range = 4 months-16 yr.). 144 swallowings were normal. Swallowing disorder was confirmed in 46 swallowings, (23 supraglottic penetrations and 23 aspirations). Considering each swallowing at 15 fps, sensitivity and specificity were, respectively, 93% (CI 0.82-0.98) and 98% (CI 0.94-0.99). The Cohen'Kappa coefficient between each interpretation at 15 and 30 fps was "almost perfect" (κ = 0.95; CI 0.88-0.99). Considering each loop, conclusion was identical. Reducing frame rate at 15 fps during pediatric VFSS seemed to be acceptable with comparable diagnostic performances without clinical impact compared to 30 fps, while being an efficient way to reduce the ionizing radiation exposition in children. We would suggest reconsidering the possibility of using VFSS with a 15 fps in a pediatric population.

Posterior fossa tumors in children: Radiological tips & tricks in the age of genomic tumor classification and advance MR technology.

Imaging plays a major role in the comprehensive assessment of posterior fossa tumor in children (PFTC). The objective is to propose a global method relying on the combined analysis of radiological, clinical and epidemiological criteria, (taking into account the child's age and the topography of the lesion) in order to improve our histological approach in imaging, helping the management and approach for surgeons in providing information to the patients' parents. Infratentorial tumors are the most frequent in children, representing mainly medulloblastoma, pilocytic astrocytoma and brainstem glioma. Pre-surgical identification of the tumor type and its aggressiveness could be improved by the combined analysis of key imaging features with epidemiologic data.

Clinical equivalence assessment of T2 synthesized pediatric brain magnetic resonance imaging.

BACKGROUND AND PURPOSE: Automated synthetic magnetic resonance imaging (MRI) provides qualitative, weighted image contrasts as well as quantitative information from one scan and is well-suited for various applications such as analysis of white matter disorders. However, the synthesized contrasts have been poorly evaluated in pediatric applications. The purpose of this study was to compare the image quality of synthetic T2 to conventional turbo spin-echo (TSE) T2 in pediatric brain MRI. MATERIALS AND METHODS: This was a mono-center prospective study. Synthetic and conventional MRI acquisitions at 1.5 Tesla were performed for each patient during the same session using a prototype accelerated T2 mapping sequence package (TAsynthetic=3:07min, TAconventional=2:33min). Image sets were blindly and randomly analyzed by pediatric neuroradiologists. Global image quality, morphologic legibility of standard structures and artifacts were assessed using a 4-point Likert scale. Inter-observer kappa agreements were calculated. The capability of the synthesized contrasts and conventional TSE T2 to discern normal and pathologic cases was evaluated. RESULTS: Sixty patients were included. The overall diagnostic quality of the synthesized contrasts was non-inferior to conventional imaging scale (P=0.06). There was no significant difference in the legibility of normal and pathological anatomic structures of synthetized and conventional TSE T2 (all P>0.05) as well as for artifacts except for phase encoding (P=0.008). Inter-observer agreement was good to almost perfect (kappa between 0.66 and 1). CONCLUSIONS: T2 synthesized contrasts, which also provides quantitative T2 information that could be useful, could be suggested as an equivalent technique in pediatric neuro-imaging, compared to conventional TSE T2.

Individual radiation exposure from computed tomography: a survey of paediatric practice in French university hospitals, 2010-2013.

OBJECTIVES: To describe computed tomography (CT) scanning parameters, volume CT dose index (CTDIvol) and dose-length product (DLP) in paediatric practice and compare them to current diagnostic reference levels (DRLs). METHODS: The survey was conducted in radiology departments of six major university hospitals in France in 2010-2013. Data collection was automatised to extract and standardise information on scanning parameters from DICOM-header files. CTDIvol and DLP were estimated based on Monte Carlo transport simulation and computational reference phantoms. RESULTS: CTDIvol and DLP were derived for 4,300 studies, four age groups and 18 protocols. CTDIvol was lower in younger patients for non-head scans, but did not vary with age for routine head scans. Ratios of 95th to 5th percentile CTDIvol values were 2-4 for most body parts, but 5-7 for abdominal examinations and 4-14 for mediastinum CT with contrast, depending on age. The 75th percentile CTDIvol values were below the national DRLs for chest (all ages) and head and abdominal scans (≥10 years). CONCLUSION: The results suggest the need for a better optimisation of scanning parameters for routine head scans and infrequent protocols with patient age, enhanced standardisation of practices across departments and revision of current DRLs for children. KEY POINTS: • CTDIvol varied little with age for routine head scans. • CTDIvol was lowest in youngest children for chest or abdominal scans. • Individual and inter-department variability warrant enhanced standardisation of practices. • Recent surveys support the need for revised diagnostic reference levels. • More attention should be given to specific protocols (sinuses, neck, spine, mediastinum).

Variability in Imaging Practices and Comparative Cumulative Effective Dose for Neuroblastoma and Nephroblastoma Patients at 6 Pediatric Oncology Centers.

The purpose of this study was to estimate the cumulative effective dose (CED) from diagnosis and posttherapy computed tomographic (CT) scans performed on children treated for neuroblastoma or nephroblastoma (Wilms tumor) and to examine the different imaging practices used in 6 regional pediatric oncology centers between January 2010 and December 2013. We analyzed retrospectively the CT scan acquisition data in children aged 10 years or younger at diagnosis. The use of nonionizing imaging modalities was reported. The CT examinations of 129 children, with a mean age at diagnosis of 36 months, treated for 66 neuroblastomas and 63 nephroblastomas, were analyzed. The mean follow-up period was 28 months (minimum, 8 months, maximum, 41 mo). There were 600 CT scans, with a total of 1039 acquisitions. The mean CED from CT scans was 27 mSv (minimum=18.25, maximum=45). Abdominal CT examinations contributed 85% of the total CED. A median of 4.6 CT scans, 10.3 sonograms, and 0.4 magnetic resonance imaging examinations per child were performed. Our results suggest a reduction in radiation exposure but variability in the imaging modality choice and acquisition protocols. We emphasize the need for consensus and standardization in oncologic pediatric imaging procedures. When feasible, we encourage the substitution of nonionizing examinations for CT.

The prevalence of lumbar spondylolysis in young children: a retrospective analysis using CT.

PURPOSE: Although lumbar spondylolysis is encountered in general population with an incidence estimated to be 3-10%, limited information is available for children. The aim of the study is to determine the prevalence of spondylolysis according to associated vertebral bony malformation and spinopelvic parameters in children under eight requiring CT evaluation for unrelated lumbar conditions. METHODS: Seven hundred and seventeen abdominal and pelvic multi-detector CT scans were obtained in patients under 8 years of age were reviewed. Two board certificated radiologists and two resident radiologists retrospectively evaluated CT scans for lumbar spondylolysis and associated malformations. Pelvic incidence and spondylolisthesis were reported. RESULTS: Our analysis included 717 CT scans in 532 children (259 girls and 273 boys). Twenty-five cases of spondylolysis were diagnosed (16 bilateral and 9 unilateral, 64 and 36%, respectively) in 14 boys (56%) and 11 girls (44%), associating with 12 grade I spondylolisthesis. The mean normal pelvic incidence was 45° (median 44°, SD 7°). The prevalence of spondylolysis was 1% in children under age 3 (n = 3 among 292 patients), 3.7% in children under age 6 (n = 17 among 454 patients) and 4.7% among the 532 patients. Unilateral spondylolysis was significantly associated with a spinal malformation (p = 0.04, Fisher's exact test), with normal pelvic incidence. Half of the patients with bilateral spondylolysis had high pelvic incidence. CONCLUSIONS: We observed a prevalence peak of unilateral spondylolysis in the context of a specific malformation in young infants under age 4 with normal pelvic incidence, and, then, a progressive increase in the prevalence of bilateral isolated spondylolysis.

Tracheobronchial Branching Abnormalities: Lobe-based Classification Scheme.

Boyden's nomenclature, which was based on postmortem specimens and published in 1955 prior to the advent of computed tomography (CT), is commonly used to describe the normal segmental bronchial anatomy and various abnormalities. However, several additional anomalies have been recognized since that time, and there is some confusion over the names used to describe these anomalies. Several congenital branching anomalies affecting the trachea, main bronchi, and intermediate bronchus have been reported, all of which can be recognized at chest CT but are often overlooked. These anomalies, which probably occur early in fetal life, can be either supernumerary, with defects occurring at 29-30 days gestation, or displaced, with defects occurring later. Tracheobronchial positional anomalies are often associated with other congenital abnormalities but may be isolated. They often are asymptomatic but can be responsible for pulmonary symptoms such as dyspnea, recurrent pneumonia, and hemoptysis. It is essential that these anomalies are recognized prior to lung resection to avoid complications, especially when video-assisted thoracoscopic surgery is performed. In addition, bronchoscopists should be aware of these anomalies before performing diagnostic or therapeutic bronchoscopic procedures. Awareness of a few key bronchial anatomic principles and use of a lobe-based classification scheme will facilitate recognition of tracheobronchial positional anomalies.

Sturge-Weber syndrome in patients with facial port-wine stain.

Facial port-wine stain (PWS) may be associated with cerebrovascular abnormalities such as Sturge-Weber syndrome (SWS). In a large series, we aimed to assess which topography of facial PWS can predict SWS. This was a cross-sectional study of consecutive patients with facial PWS seen in pediatric dermatologic or angiodysplasia consultations from 1993 to 2005 at the University Hospital Center of Tours. A standardized form was used to collect data on clinical and imaging findings. Patients with and without SWS were compared in terms of topography of the cutaneous angioma and related ophthalmologic and neurologic features. Two hundred fifty-nine patients were included, 15 with a diagnosis of SWS. All patients with SWS showed involvement of the V1 trigeminal cutaneous area. SWS was significantly associated with bilateral topography of the PWS, its extension to another territory, and involvement of the upper eyelid. Knowledge of the topography of facial PWS with risk of associated neurological or ocular anomalies allows for early diagnosis of SWS and avoids unnecessary and costly radiography for patients with uncomplicated facial PWS.

Proton MR spectroscopic imaging of basal ganglia and thalamus in neurofibromatosis type 1: correlation with T2 hyperintensities.

INTRODUCTION: Neurofibromatosis type 1 (NF1) is frequently associated with hyperintense lesions on T2-weighted images called "unidentified bright objects" (UBO). To better characterize the functional significance of UBO, we investigate the basal ganglia and thalamus using spectroscopic imaging in children with NF1 and compare the results to anomalies observed on T2-weighted images. METHODS: Magnetic resonance (MR) data of 25 children with NF1 were analyzed. On the basis of T2-weighted images analysis, two groups were identified: one with normal MR imaging (UBO- group; n = 10) and one with UBO (UBO+ group; n = 15). Within the UBO+ group, a subpopulation of patients (n = 5) only had lesions of the basal ganglia. We analyzed herein seven regions of interest (ROIs) for each side: caudate nucleus, capsulo-lenticular region, lateral and posterior thalamus, thalamus (lateral and posterior voxels combined), putamen, and striatum. For each ROI, a spectrum of the metabolites and their ratio was obtained. RESULTS: Patients with abnormalities on T2-weighted images had significantly lower NAA/Cr, NAA/Cho, and NAA/mI ratios in the lateral right thalamus compared with patients with normal T2. These abnormal spectroscopic findings were not observed in capsulo-lenticular regions that had UBO but in the thalamus region that was devoid of UBO. CONCLUSION: Multivoxel spectroscopic imaging using short-time echo showed spectroscopic abnormalities in the right thalamus of NF1 patients harboring UBO, which were mainly located in the basal ganglia. This finding could reflect the anatomical and functional interactions of these regions.

A Dose Simulation X-Ray Software: An Innovating Tool to Reduce Chest Radiograph Exposure in Children.

PURPOSE: Chest radiography is one of the most frequent x-ray examinations performed on children. Reducing the delivered dose is always a major task. The objective of our study was to determine the minimum dose to be delivered while maintaining the image quality of chest radiographs, using dose reduction simulation software. MATERIALS AND METHODS: We included 60 children who had had a chest radiography in 5 groups established according to the diagnostic reference levels equitably represented by weight ranges. The software simulated for each radiograph 6 additional simulated photonic noise images corresponding to 100%, 80%, 64%, 50%, 40%, and 32% of the initial dose. The 360 radiographs were blindly scored by 2 radiologists, according to the 7 European quality criteria and a subjective criterion of interpretability, using a semiquantitative visual Lickert scale. RESULTS: There was no significant difference in scoring between the reference radiograph (100%) and simulated radiographs at 80% of the dose in children between 5 and 20 kg, 50% of the dose in children between 20 and 30 kg, and between simulated radiographs at 40% of the dose in children over 30 kg. Interobserver reproducibility was moderate to excellent. CONCLUSION: Chest radiography dose might be reduced by 20% in children between 5 and 20 kg, 50% in children between 20 and 30 kg, and 60% in children over 30 kg, without any difference in the image quality appreciation. Software that produced simulated x-ray with decreasing delivered dose is an innovating tool for an optimization process.

REDUCING PELVIS RADIOGRAPH EXPOSURE IN CHILDREN USING A DOSE SIMULATION X-RAY RESEARCH SOFTWARE.

Pelvis radiography is a frequent X-ray examination. The objective of our study was to determine the minimum dose to be delivered without reducing the quality. We included 60 children having a pelvis X-ray in four groups that were equally represented by weight ranges. A software simulated, for each radiograph, six additional simulated photonic noise images corresponding to 100, 80, 64, 50, 40 and 32% of the initial dose. The 360 radiographs were blindly scored by two radiologists using a semi-quantitative Likert scale. There was no significant difference in scoring between the reference radiograph and simulated radiographs at 80% of the dose in children between 0 and 15 kg and over 35 kg. Inter-observer reproducibility was moderate to very good. Pelvis X-ray doses might be reduced by 20% in children in our institution. Software that produces simulated X-ray with decreasing dose might be a useful tool for an optimization process.

Automated brain MRI metrics in the EPIRMEX cohort of preterm newborns: Correlation with the neurodevelopmental outcome at 2 years.

PURPOSE: The purpose of this study was to identify in the EPIRMEX cohort the correlations between MRI brain metrics, including diffuse excessive high signal intensities (DEHSI) obtained with an automated quantitative method and neurodevelopmental outcomes at 2 years. MATERIALS AND METHODS: A total of 390 very preterm infants (gestational age at birth≤32 weeks) who underwent brain MRI at term equivalent age at 1.5T (n=338) or 3T (n=52) were prospectively included. Using a validated algorithm, automated metrics of the main brain surfaces (cortical and deep gray matter, white matter, cerebrospinal fluid) and DEHSI with three thresholds were obtained. Linear adjust regressions were performed to assess the correlation between brain metrics with the ages and stages questionnaire (ASQ) score at 2 years. RESULTS: Basal ganglia and thalami, cortex and white matter surfaces positively and significantly correlated with the global ASQ score. For all ASQ sub-domains, basal ganglia and thalami surfaces significantly correlated with the scores. DEHSI was present in 289 premature newborns (74%) without any correlation with the ASQ score. Metrics of DEHSI were greater at 3T than at 1.5T. CONCLUSION: Brain MRI metrics obtained in our multicentric cohort correlate with the neurodevelopmental outcome at 2 years of age. The quantitative detection of DEHSI is not predictive of adverse outcomes. Our automated algorithm might easily provide useful predictive information in daily practice.

Detection of recurrent brain tumors in children: No significant difference in sensitivity between unenhanced and contrast-enhanced MRI.

BACKGROUND: Magnetic resonance imaging (MRI) with a gadolinium injection is currently used in the follow-up of children in remission of cerebral tumors (CTs). Intracerebral gadolinium deposition has been recently reported with unknown risks. The aim of this study was to evaluate the sensitivity of unenhanced brain MRI (U-MRI) in detection of tumor recurrence. METHODS AND MATERIALS: A set of 58 U-MRIs of children in remission was retrospectively evaluated by three seniors (a neuroradiologist, a pediatric and a general radiologist) and one junior to look for any recurrence. Clinical, tumoral and imaging data were collected. The final diagnosis was anatomopathological when available, or the clinicoradiological evolution. Sensitivity, specificity, predictive values and interobserver agreement were calculated. A Fisher test and Fleiss kappa coefficient were performed. RESULTS: For the seniors, the U-MRI had a sensitivity of 81% (95% confidence interval (CI): 0.56-0.90), and a negative predictive value (NPV) of 82% (95% CI: 0.63-0.94). The U-MRI sensitivity, regardless of the observer, was not significantly different from the contrast-enhanced MRI sensitivity (86%) according to a Fisher test (p > 0.05). No significant difference in sensitivity within the subgroups was found. The interobserver agreement of seniors was good (κ = 0.68). CONCLUSION: U-MRI brain was suboptimal for 80% of patients. Three-dimensional millimetric, fluid-attenuated inversion recovery, and diffusion would constitute helpful sequences in follow-up. Further specific studies depending on each tumor type are still required to determine whether a potential abstention of gadolinium intravenous injection should be discussed for children.

Sonography of suspected acute appendicitis in children: Evaluation of the progress in performance of senior residents.

PURPOSE: The objective of this study was to evaluate the progress in performance of senior residents in diagnosing acute appendicitis. MATERIAL AND METHODS: Results were collected and compared of ultrasound examinations performed for suspected acute appendicitis by three senior residents and two faculty members over a six-month period in a university hospital setting. A grid with the sonographic findings was completed separately by the residents and the faculty members immediately after each examination. The duration of each examination was reported. The final ultrasound diagnosis was compared to the surgical and pathological results and to the clinical follow-up. RESULTS: The residents and faculty members performed 171 consecutive ultrasound examinations including 49 children with acute appendicitis and 122 with normal appendices. The accuracy of the diagnosis by the residents was 96%, and was similar to that of the faculty members (kappa=0.90) over the six months. The duration of the resident ultrasound examinations was significantly shorter during the second three-month period (p=0.01). No significant differences in diagnostic accuracy were demonstrated by the residents between the first and second three-month periods (p=0.06). CONCLUSIONS: The residents performed well when using sonography to diagnose acute appendicitis in children, and were faster during the second three-month period. LEVEL OF EVIDENCE: I.

Systematic ultrasound examinations in neonates admitted to NICU: evolution of portal vein thrombosis.

OBJECTIVE: The aim of the study was to better describe incidence, risk factors, and the natural evolution of neonatal portal vein thrombosis (PVT). STUDY DESIGN: One hundred and twenty-three premature newborns or with birth weight <1.5 kg were prospectively included in a single center during a one-year period. Three systematic abdominal ultrasound examinations at day 3, day 10, and day 45 (and 1 year in case of persistent PVT) were performed. Clinical and biological data were recorded. RESULTS: Seventy neonates (57%) had three normal US examinations. Fifty-three neonates (43%) had a clinical and biological asymptomatic left PVT. No right or extrahepatic portal venous thrombosis was observed. Umbilical vascular catheter (UVC) was removed in case of PVT. No anticoagulation therapy was required. No risk factor was significantly associated with PVT. At 1 year of follow-up, five infants had persistent isolated left PVT (4%). CONCLUSION: A spontaneous favorable evolution of left PVT occurred in more than of 95%.

Constant delay in adapted cerebral response to light stimulation in premature neonates: a transcranial Doppler study.

Transcranial Doppler has been used previously to determine hemodynamic response to sensorial stimulation in adults but not in the neonatal period. Cerebral blood flow velocity (CBFV) was recorded in both middle cerebral arteries (MCA) and posterior cerebral arteries (PCA) in 100 premature neonates (male 56; female 44; 26 to 36 weeks gestation) from birth to 12 months. Brain development was evaluated on clinical examination. No difference in velocities was noted on prestimulation recordings from birth to 12 months. During light stimulation before six months, the CBFV was reduced (-11 +/- 6% in MCA and -13 +/- 5% in PCA compared with baseline values). After stimulation, the CBFV was increased (+6.7 +/- 3% in MCA and + 10.5 +/- 4% in PCA compared with baseline values). This study is in favor of cortex maturation in normal premature neonates at only six months. Consequently, functional transcranial Doppler technique will be helpful for the diagnosis of abnormal maturation timing in neonates with possible developmental retardation.