Cerebellar haemorrhages and pons development in extremely low birth weight infants

Neuropathological and Magnetic Resonance Imaging (MRI) studies showed a high frequency of posterior fossa abnormalities in preterms. To assess whether cerebellar haemorrhages (CH) diagnosed with ultrasound and/or MRI affect pons development in ELBW infants. The anteroposterior diameter of the pons was measured manually on the midline sagittal T1 MR image in 75 ELBW babies consecutively scanned at term postmenstrual age. Subjects with CH were identified and compared to babies with no posterior fossa bleeding. Nine ELBW infants with CH (CH-Group: median gestational age -GA- 26 wks, range 23-27; birth weight -BW- 680 g, 425-980) were compared with 66 babies with normal cerebellum (Control-Group: GA 28 wks, 23-33; BW 815 g, 430-1000). The two groups were comparable for BW (p=0.088) while GA was significantly shorter in CH babies (p=0.005). The pontine diameter was significantly lower in CH-Group compared to Control-Group (12.8 +/- 2.2 vs 14.8 +/- 1.2 mm; p<0.001).

CONCLUSIONS

Cerebellar haemorrhages seem to affect the development of the pons in ELBW with the youngest GA.

Prenatal MR imaging of the normal pituitary stalk

BACKGROUND AND PURPOSE

Prenatal imaging data of the normal pituitary gland and in vivo information on the development of the pituitary region are lacking; however, we noticed that the pituitary stalk (PS) is visible occasionally in utero on MR images. Our main purpose was to establish the detection rate of the PS in healthy fetuses at various gestational ages (GAs) by using single-shot fast spin-echo T2-weighted images.

MATERIALS AND METHODS

We selected 73 fetal cases with normal findings on prenatal MR imaging and clinical postnatal follow-up. The GA ranged between 19 and 37 weeks. The 3 planes of MR imaging sections were 4 mm thick with 1.25 x 1.25 mm in-plane resolution. Two pediatric neuroradiologists evaluated in consensus whether the PS was present as a linear isointense structure connecting the hypothalamic region with the floor of sella turcica. In those cases in which the PS was visible on the sagittal section, the angle formed by the intersection of the PS and the sellar plane (SP) was measured (PS-SP angle).

RESULTS

The PS was detectable on at least 1 coronal or sagittal section from 19 to 25 weeks' GA in 30/42 fetuses (71.4% sensitivity); from 26 to 37 weeks' GA, the PS was detected in all 31 fetuses (100% sensitivity). The PS-SP angle decreased significantly with GA, being <90 degrees in all fetuses after gestational week 25.

CONCLUSIONS

At the current spatial resolution of clinical prenatal MR imaging, PS can be reliably detected after 25 weeks' GA, so in case of a missing visualization, a strong suspicion of pituitary region anomaly could be raised.

Norman-Roberts syndrome: characterization of the phenotype in early fetal life

PURPOSE

Our purpose is to describe the prenatal manifestation of Norman-Roberts syndrome and to expand the knowledge of the fetal phenotype of this rare condition. The recurrence in two sibs might contribute to the hypothesis of a recessive condition.

METHODS

Three cases are presented in which the diagnosis was suggested by a prenatal ultrasound examination and confirmed by pathology of the fetuses, after termination of pregnancy. The major sign was the ultrasound detection of microcephaly at the 22nd and 23rd week of gestation. Fetal Magnetic Nuclear Resonance, the pathological examination with histological studies, was applied to arrive at the diagnosis of Norman-Roberts syndrome.

CONCLUSION

To the best of our knowledge, this is the second description of prenatal cases of Norman-Roberts syndrome. The combined clinical and pathological data is a contribution that might help to increase the identification of this rare condition and to correctly define the risk of its recurrence.

Imaging techniques in the diagnosis and management of rhinosinusitis in children

Sinusitis in children is a common problem. The diagnosis of both acute and chronic rhinosinusitis in the pediatric population, should be made first of all clinically, and not on the basis of imaging findings alone. Plain radiography may be used as a screening method for various pathological conditions of sinuses, but computed tomography (CT) remains the study of choice for the imaging evaluation of acute and chronic rhinosinusitis. In acute sinusitis, CT is indicated in patients with symptoms persisting after 10 days of appropriate therapy and in patients with suspected complications (especially in the brain and in the orbit). In addition to CT scanning, magnetic resonance (MR) imaging of the sinuses, orbits, and brain should be performed whenever extensive or multiple complications of sinusitis are suspected. In chronic sinusitis, CT scanning is the 'gold standard' for the diagnosis and the management, because it also provides an anatomic road map, when surgery is required. Nuclear medicine studies and ultrasound are rarely indicated in acute and chronic rhinosinusitis.

Disorders of cognitive and affective development in cerebellar malformations

Acquired cerebellar lesions in adults and children can lead to the development of a complex behavioural pattern termed 'Cerebellar Cognitive Affective Syndrome' (Schmahmann and Sherman, Brain, 1998; 121: 561-79), which is characterized by reduced cognitive efficiency associated with specific neuropsychological deficits (executive and visuospatial disorders), expressive language disorders (mild agrammatism and anomia) and affective disorders with blunting of affect. It is not known whether a symptomatological picture such as this can also be found in congenital cerebellar malformations. We studied the behavioural developmental profile of 27 patients including children and adults with congenital malformations confined to the cerebellum, the largest studied sample to date. Extensive clinical and neuropsychological investigations highlight the presence of a wide range of disorders supporting the important role played by the cerebellum in the acquisition of higher-order cognitive and affective skills. The type and extent of cerebral reorganization processes in the presence of malformative lesions are difficult to predict and may possibly account for the variability of clinical phenotypes. It is, therefore, more difficult to identify a syndromic picture defined as exactly as is the case with acquired lesions. However, the pattern of deficits that we document is in remarkable agreement with the general profile of the Cerebellar Cognitive Affective Syndrome. Malformations affecting the cerebellar vermis induce affective and social disorders and evolve towards more unfavourable pictures often associated with an autistic symptomatology. Malformations of cerebellar hemispheres are more frequently associated with selective neuropsychological deficits involving mainly executive functions and visuospatial and linguistic abilities. Motor deficits are generally less severe, and tend to improve slowly and progressively, in some cases reaching almost complete functionality. Finally, the overall favourable evolution with an onset of skills in advanced age in a consistent subset of subjects suggests that individual follow-ups should be performed in order to monitor the quality and stability of impairments and acquired abilities over time.

Diffusion-weighted magnetic resonance imaging of acute hypoxic-ischemic cerebral lesions in the survivor of a monochorionic twin pregnancy: case report

Monochorionic twin pregnancies complicated by the death of one twin are associated with substantial morbidity in the survivor, with a high risk of developing hypoxic-ischemic brain damage. In this report, we demonstrate how prenatal diffusion-weighted magnetic resonance imaging detected focal ischemic lesions in the survivor of a monochorionic twin pregnancy within 1-2 days of cotwin death. A very early diagnosis of cerebral ischemic lesions might influence the management of the pregnancy. Published by John Wiley & Sons, Ltd.

Brain magnetic resonance imaging in Wolf-Hirschhorn syndrome

Wolf-Hirschhorn syndrome (WHS) is a rare genetic disorder, which is caused by partial deletion of the short arm of one chromosome 4. Brain magnetic resonance (MR) imaging findings are lacking. We report on brain findings in 10 children with WHS. We evaluated the MR imaging films of 10 subjects affected by WHS, which had been confirmed by genetic study. The age range at MR imaging was between 1 month and 9 years. In 9/10 cases enlargement of the third lateral ventricles was present. In 9/10 cases a global reduction of cerebral hemispheres white matter was present. In 10/10 cases diffuse thinning of the corpus callosum was visible; it was severe in 7/10 cases. In 5/10 cases small foci of T (2) hyper intense signal were visible within the subcortical white matter. In three of the six cases studied within the first year of life frontal periventricular cysts were present. In three of the four cases studied after the first year of life a squared shape of the frontal horns of the lateral ventricles was visible. The MR imaging findings reported in WHS cannot be considered pathognomonic of the syndrome, however, they may suggest WHS.

Magnetic resonance imaging of fetal cerebellar development

In the last few years fetal magnetic resonance imaging (MRI) has been proposed as a second level technique in the evaluation of fetal brain anomalies. It has been demonstrated that MRI is highly accurate in illustrating the morphologic changes of developing brain and fetal brain abnormalities being a useful procedure when ultrasonography is inconclusive or doubtful. Starting from the 19-20 weeks gestational age (GA), MRI can reliably depict fetal brain anatomy and locating pathology, offering a robust and reliable tool in the assessment of fetal CNS diseases. In this review both in vivo MRI quantitative and qualitative data about fetal cerebellar development are presented and compared with ultrasonography data. Fetal cerebellar development is gradual, steady, and largely comparable to the development of the supratentorial brain. Archicerebellar (flocculo-nodular lobe) and paleocerebellar (vermis) structures develop first, whereas neocerebellum (cerebellar hemispheres) develop slowly and largely after birth.

Magnetic resonance imaging assessment of brain maturation in preterm neonates with punctate white matter lesions

INTRODUCTION

Early white matter (WM) injury affects brain maturation in preterm infants as revealed by diffusion tensor imaging and volumetric magnetic resonance (MR) imaging at term postmenstrual age (PMA). The aim of the study was to assess quantitatively brain maturation in preterm infants with and without milder forms of WM damage (punctate WM lesions, PWML) using conventional MRI.

METHODS

Brain development was quantitatively assessed using a previously validated scoring system (total maturation score, TMS) which utilizes four parameters (progressive myelination and cortical infolding, progressive involution of glial cell migration bands and germinal matrix tissue). PWML were defined as foci of increased signal on T1-weighted images and decreased signal on T2-weighted images with no evidence of cystic degeneration. A group of 22 preterm infants with PWML at term PMA (PWML group) were compared with 22 matched controls with a normal MR appearance.

RESULTS

The two groups were comparable concerning gestational age, birth weight and PMA. TMS was significantly lower in the PWML group than in the control group (mean TMS 12.44 +/- 2.31 vs 14.00 +/- 1.44; P = 0.011). Myelination (mean 2.76 +/- 0.42 PWML group vs 3.32 +/- 0.55 control group, P = 0.003) and cortical folding (3.64 +/- 0.79 vs 4.09 +/- 0.43, P = 0.027) appeared to be significantly delayed in babies with PWML.

CONCLUSION

Conventional MRI appears able to quantify morphological changes in brain maturation of preterm babies with PWML; delayed myelination and reduced cortical infolding seem to be the most significant aspects.

Hippocampal infolding angle changes during brain development assessed by prenatal MR imaging

BACKGROUND AND PURPOSE

Epileptic syndromes or neurodevelopmental delay may be associated with congenital anomalies of the shape or the orientation of the hippocampus. Scarce data are available about quantitative hippocampal developmental changes during fetal life, in particular about the progressive rotational changes of the hippocampal infolding angle (HIA), which can be considered a hallmark of hippocampal development. We hypothesized that prenatal MR imaging could demonstrate the progressive rotation of the hippocampus, providing quantitative data by means of the HIA determination.

METHODS

We retrospectively selected 62 fetal MR imaging cases with normal brain at prenatal and postnatal imaging. The gestational age ranged from 20 to 37 weeks. The coronal section encompassing the pons was used to perform the measurement of HIA. HIA was defined as the angle between the line connecting the lateral margin of the cornu ammonis with the medial superior margin of the subiculum and the line passing through the midline structures.

RESULTS

A significant positive correlation was found between the HIA value and the gestational age. The HIA was generally below 70 degrees before the gestational week 25 and above 70 degrees after week 30.

CONCLUSION

Prenatal MR imaging allowed the progressive rotation of hippocampus to be detected during fetal life, providing normative data about HIA changes. These data could support further investigations to assess how fetal HIA anomalies might affect postnatal neurologic outcome.

Patterns of damage in the mature neonatal brain

Patterns of damage in the mature neonatal brain can be subdivided into focal, multifocal and diffuse. The main cause of diffuse brain damage in the term newborn is hypoxic-ischaemic encephalopathy (HIE). HIE is still the major recognized perinatal cause of neurological morbidity in full-term newborns. MRI offers today the highest sensitivity in detecting acute anoxic injury of the neonatal brain. Conventional acquisition techniques together with modern diffusion techniques can identify typical patterns of HIE injury, even in the early course of the disease. However, even though highly suggestive, these patterns cannot be considered as pathognomonic. Perinatal metabolic disease such as kernicterus and severe hypoglycaemia should be differentiated from classic HIE. Other conditions, such as infections, non-accidental injury and rarer metabolic diseases can be misinterpreted as HIE in their early course when diffuse brain swelling is still the predominant MRI feature. Diffusion techniques can help to differentiate different types of diffuse brain oedema. Typical examples of focal injuries are arterial or venous infarctions. In arterial infarction, diffusion techniques can define more precisely than conventional imaging the extent of focal infarction, even in the hyperacute phase. Moreover, diffusion techniques provide quantitative data of acute corticospinal tract injury, especially at the level of the cerebral peduncles. Venous infarction should be suspected in every case of unexplained cerebral haematoma in the full-term newborn. In the presence of spontaneous bleeding, venous structures should always be evaluated by MR angiography.

Spinal cord and vertebral stroke: a paediatric case

Spinal cord ischaemia is a rare entity and very few cases of simultaneous spinal cord and vertebral body infarction have been reported: all of them in adult age. We observed a 15-year-old girl with abrupt onset of myelopathy and pain at the vertebral column studied by means of serial magnetic resonance imaging (MRI), and in whom bone infarction was a confirmatory sign of the vascular origin of the spinal lesion. This is to the best of our knowledge the first paediatric case described in the literature.

Thrombophilia and fetal germinal matrix-intraventricular hemorrhage: does it matter?

Germinal matrix-intraventricular hemorrhage (GMH-IVH) in the fetus is very rare and the role of thrombophilia in its pathogenesis is unclear. We report on the prenatal diagnosis by magnetic resonance imaging of GMH-IVH in a 24-week fetus. The newborn presented posthemorrhagic ventriculomegaly and was found to be heterozygous for two thrombophilic patterns, factor V Leiden and methylenetetrahydrofolate reductase mutation. The combination of this hypercoagulable state and prenatal GMH-IVH is discussed together with the opportunity of testing these infants for thrombophilia.

MRI of fetal and neonatal cerebellar development

In the last few years magnetic resonance imaging (MRI) has expanded its diagnostic capability in the evaluation of fetal brain. Starting from the 18th to 20th gestational weeks, MRI can reliably depict fetal brain anatomy and locate pathology, offering a robust and reliable tool for the assessment of disorders of the fetal central nervous system. In this review quantitative and qualitative in vivo MRI data on fetal cerebellar development are presented. Our normative reference data have been obtained from a database of 580 MR fetal imaging studies. Normal cases were selected within normal MRI fetal brain studies, and all selected cases had a normal clinical evaluation and a normal cranial ultrasound or MR image after birth. Fetal cerebellar development is gradual, steady, and grossly comparable to the development of the supratentorial brain. Archicerebellar (flocculonodular lobe) and paleocerebellar (vermis) structures develop before the neocerebellum (cerebellar hemispheres) that develops more slowly and largely after birth.

Brain apparent diffusion coefficient decrease during correction of severe hypernatremic dehydration

We report on the brain diffusion MR imaging findings in a neonate with severe hypernatremic dehydration, which resulted in cerebral edema (osmotic edema) and in apparent diffusion coefficient decrease, despite a careful and slow rehydration. This report provides in vivo insight into nervous cell response to osmotic challenge.

Neuroradiology of multiple sclerosis in children

Neuroimaging features of multiple sclerosis in children can differ from the usual adult pattern. Frequently, lesions can be more larger and pseudo-tumoral with a variable evolution. The most critical differential diagnosis in childhood is with acute disseminated encephalomyelitis that is a relatively frequent acquired inflammatory disease of the white matter with a polymorphous appearance. Some differences between multiple sclerosis and acute disseminated encephalomyelitis in children such as distribution of white matter lesions and frequency of gray matter involvement should be pointed out. Neveretheless only follow-up examination can make the definitive diagnosis in the majority of the cases.

Frontal bilateral megalencephaly: fetal and autopsy MR evaluation of an unclassified malformation

OBJECTIVE

To describe an unreported brain malformation with in utero onset.

METHODS

A 21-weeks-of-gestational-age fetus underwent prenatal MR imaging because of macrocephaly detected by ultrasound. Prenatal MR imaging revealed a complex brain malformation. At 22 weeks of GA, pregnancy was terminated; an MR autopsy study was also performed.

RESULTS

MR imaging revealed frontal bilateral megalencephaly and malformation of cortical development, suggesting polymicrogyria. These findings do not fit into any of the known megalencephalic syndromes.

CONCLUSIONS

To our knowledge, this is a previously unreported malformation. Fetal and autoptic MR examination have been the best tools in understanding this complex brain pathology, allowing a more complete genetic counseling.

Prenatal Magnetic Resonance Imaging of Rhombencephalosynapsis and Associated Brain Anomalies

Rhombencephalosynapsis (RES) is a rare congenital abnormality characterized by vermian agenesis and fusion of the cerebellar hemispheres. In the 3 cases reported here, prenatal magnetic resonance imaging clearly depicted cerebellar features characteristic of RES, allowing a definite diagnosis.

MR imaging of the superior profile of the midbrain: differential diagnosis between progressive supranuclear palsy and Parkinson disease

BACKGROUND AND PURPOSE

Quantitative evaluation of midbrain atrophy may be useful in differentiating progressive supranulear palsy (PSP) from Parkinson disease (PD); however, this finding is not specific of PSP, and quantitative measurements are not always practical. We determined whether an abnormal superior midbrain profile (flat or concave aspect) is a more practical diagnostic parameter for PSP.

METHODS

MR imaging studies of 25 patients with PSP and 27 with PD were reviewed by means of five parameters: midbrain superior profile on midsagittal T1-weighted images, midbrain atrophy, tegmental abnormal T2 hyperintensity, abnormal T2 putaminal hypointensity or hyperintensity on axial proton density-weighted images. We also measured the anteroposterior diameter of the midbrain on axial T2-weighted sections at the level of the superior colliculus.

RESULTS

The finding of an abnormal superior profile of the midbrain had 68% sensitivity and 88.8% specificity. Midbrain atrophy had 68% sensitivity and 77.7% specificity. Tegmental T2 hyperintensity had 100% specificity but poor sensitivity (28%). Only 14.8% of patients with PD and 24% of those with PSP had abnormal putaminal T2 hypointensity; none had proton-density hyperintensity. With PSP, the average midbrain diameter was smaller than that with PD, but an important overlap was observed. Reader discordance was lower for the midbrain superior profile sign (eight of 52 cases); this was similar for tegmental hyperintensity (nine of 52 cases) and higher for midbrain atrophy (16 of 52 cases).

CONCLUSION

An abnormal superior profile of the midbrain facilitates the distinction of PSP from PD and may support the clinical differential diagnosis of parkinsonism.