Cerebral biometry in fetal magnetic resonance imaging: new reference data

OBJECTIVES

To provide normal magnetic resonance imaging (MRI) reference biometric data of the fetal brain, to evaluate reproducibility and gender effect, to compare the two cerebral hemispheres and to compare MRI with ultrasonographic biometry, in a large cohort.

METHODS

Normal cerebral fetal MRI examinations were collected prospectively and several parameters were measured: the supratentorial space (bone and cerebral fronto-occipital and biparietal (BPD) diameters), the length of the corpus callosum (LCC), the surface area, height and anteroposterior diameter of the vermis, the transverse cerebellar diameter (TCD) and the anteroposterior diameter of the pons. We evaluated the interobserver reproducibility of measurements and the possible gender effect on measurements of bone BPD, TCD and LCC. We compared right and left hemispheres, right and left atria and ultrasound and MRI measurements.

RESULTS

The study included 589 fetuses, ranging from 26 to 40 weeks. Normal values (from 3(rd) to 97(th) percentile) are provided for each parameter. Interobserver agreement was excellent, with an intraclass correlation coefficient (ICC) > 0.75 for many parameters. The gender effect was evaluated in 372 cases and did not reveal any clinically meaningful difference. Comparison between the right and left cerebral hemispheres and between the right and left atria did not reveal any meaningful differences. Ultrasound and MRI measurements of BPD and TCD were compared in 94 cases and 48 cases, respectively, and the agreement was excellent (ICC = 0.85).

CONCLUSIONS

We present new reproducible reference charts for cerebral MRI biometry at 26-40 weeks' gestation, from a large cohort of fetuses.

Anomalies cérébrales subtiles de l’Adrénomyéloneuropathie

PURPOSE

To describe subtle brain abnormalities detected on MRI in adult patients with adrenomyeloneuropathy (AMN). Materials and methods. Retrospective evaluation of data acquired prospectively as part of a clinical trial (Riluzole) in 66 adult patients with AMN without obvious brain lesion on MR. All patients underwent brain MR including T1W, T2W, FLAIR and spectroscopy. After a review had been validated by three different reviewers, review of MR images was performed by consensus using a semi-quantitative scale.

RESULTS

Preliminary analysis of MR images confirmed the presence of signal abnormalities involving the corticospinal tracts in 36 patients (54.6%). Additional subtle abnormalities were also detected: white matter palor, mainly parieto-occipital in location, with patchy hyperintensity in 36 patients (54.6%), hyperintense pontocerebellar fibers on T2W and FLAIR in 25 patients (41.7%). The presence of elevated Cho/Cr and mI/Cr ratios, described in the literature, were confirmed.

CONCLUSION

This retrospective study allows the description of an AMN pattern on MRI in patients without white matter or callosal abnormalities.

[Benefit of hip ultrasound in management of the limping child]

OBJECTIVE

To evaluate the contribution of sonography of the hip in the management of nontraumatic limping in children.

PATIENTS AND METHODS

Prospective study including children consulting for nontraumatic limping (n=93). These children had a clinical examination, a biological and imaging workup (pelvis x-rays (n=88), initial sonograph of the hip (n=93), and follow-up sonograph of the hip (n=29)).

RESULTS

Ninety-three children (69 boys, 24 girls) aged from 10 months to 13 years (median, 4 years) were included and divided into two groups: The sensitivity and specificity of sonography in establishing a serious diagnosis was 57% and 59%, respectively.

CONCLUSION

The advantage of systematic hip sonography is challenged in this study because of low sensitivity and specificity. Its main advantage seems to be in its negative results, which prompt other investigations.

Tuberculose de l'enfant après contage familial : une expérience en pédiatrie générale

The heterogeneity of clinical presentations of children in contact with a tuberculous adult do not allow simple guidelines for treatment and exams. Indications of thoracic computed tomography (CT) in young children and the risk of a follow-up without antituberculous treatment are always discussed.

PATIENTS

Sixty-nine children, belonging to 50 families, living in close contact with an adult treated for tuberculosis were explored during 7 years in a General Pediatric Unit. A CT was performed in 51 patients.

RESULTS

Mantoux test was negative in 3/17 children with typical tuberculous disease on X-ray. When results of CT were compared with those of standard thoracic X-ray, a difference for the diagnosis of mediastinal adenopathies was found only in children younger than 5 years. Fifty-eight patients were given usual treatment of latent or patent tuberculosis if indicated, or a chemoprophylaxis. All of them had normal clinical and X-ray exam 2 to 4 years later. Eleven children, initially checked in an other unit, were given no treatment, but a follow-up was set up. However, after 6 to 24 months, 4/11 had a patent tuberculosis and 5/11 a latent tuberculosis, 6/9 being aged more than 3 years.

CONCLUSION

This study shows that risk of tuberculosis after familial contamination is high, and that the choice of absence of treatment with following re-evaluation, is sometimes questionable because families or doctors do not perform the prescribed follow-up. To perform systematically a thoracic CT, searching for mediastinal adenopathies, is useful only before the age of 5 years.

Imagerie cérébrale de la sclérose tubéreuse de bourneville chez l’enfant

Tuberous sclerosis (TS) is a frequent phakomatosis, with autosomal dominant transmission. The diagnosis relies on a list of criteria (2 major criteria or 1 major criterion and 2 minor criteria). Brain MRI is very important for diagnosis, already showing the major signs during fetal life: subependymal nodules, tubers and giant cell astrocytomas. In childhood, FLAIR sequences are the more interesting while in fetuses, neonates and infants T1 sequences are required because of the myelination process.

Imagerie de la pathologie iatrogène médicamenteuse

Iatrogenic drug disorders should be considered when presented with a number of imaging findings mainly involving the nervous, musculoskeletal, gastrointestinal or genitourinary system. Care should be used when differentiating between imaging findings related to the underlying pathology and imaging findings related to drug-related complications: examples include the impact of steroid therapy on bones and the impact of triple-drug anti-HIV therapy and its impact of fatty tissue. Knowledge of the necessary imaging surveillance protocol is implied.

Évaluation des doses d’irradiation aux organes en scanographie pédiatrique

PURPOSE

To estimate radiation doses from routine pediatric CT scans (body) and to propose dose reduction protocols.

MATERIAL AND METHODS

[corrected] Study performed with a phantom equivalent to the body of 5 year old child with evaluation of doses delivered to breast, gonads, bone marrow (sternum, T12) and thyroid for CT examinations of the chest, abdomen, pelvis and spine. Extrapolation is made to estimate the doses for 1 year old and 10 year old children. Finally, dose reduction protocols are evaluated.

RESULTS

CT of the chest delivers significant doses to breast tissue and bone marrow, CT of the abdomen and pelvis delivers significant doses to the ovaries and CT pf the spine delivers significant doses to thyroid and bone marrow. Optimization can be achieved without degradation of the image quality, by reducing Kv and mAs within reasonable limits. This study may be used in order to evaluate the doses delivered by multi-detector CT units.

Traumatismes du rachis chez l’enfant

Spine injuries in the pediatric population can lead to instability and subsequent neurological damage. Initial work up includes frontal and lateral cross-table spine radiographs, completed by CT and MRI when any doubt exists about possible injury. At the cervical level, injuries frequently involve the first three segments.

Les hémangiomes palpébraux du nourisson : apport de l’IRM

OBJECTIVES

To describe the MR imaging features and patterns of local extension of hemangiomas of the eyelid in correlation with the clinical presentation.

PATIENTS AND METHODS

Retrospective study including 21 MRI (GE, 1.5T, T1 +/- Gadolinium, T2 +/- fat saturation, 3 planes) examinations performed for eyelid hemangiomas with occlusion>50% and/or ocular deviation. All examinations were reviewed by two observers using a standardized list of criteria.

RESULTS

All hemangiomas had a heterogeneous signal described as "salt and pepper" on T2W sequences. The extension was extra-orbital in 8 cases, intra-orbital in 13 cases, extra-conal in 9 cases, intra-conal in 4 cases. The "fat sat T2" sequence provided the best anatomical details. There was a strong correlation between ocular deviation at clinical examination and intra-orbital extension, but no correlation between the extent of eyelid involvement and orbital location of the hemangioma. Dysplastic cerebellum anomalies related to the PHACES syndrome were present in 3 patients.

CONCLUSION

MRI of the brain and orbits provides information that appears essential for optimal management of infants with hemangioma of the eyelid.

Validation of the relative 3D orientation of vertebrae reconstructed by bi-planar radiography

The three dimensional (3D) reconstruction of the spine can be obtained by stereoradiographic techniques. To be safely used on a routine clinics basis, stereoradiography must provide both accurate vertebral shape and coherent position. Although the accuracy of the reconstructed morphology of the vertebrae is well documented, only few authors studied the accuracy of the vertebral orientation. Therefore, this paper focuses on the evaluation of the orientation accuracy of the reconstructed vertebrae (obtained by non-stereo corresponding point technique) considering either a 178 point vertebral model or a 6 point vertebral model (previously proposed in the literature). Five dried vertebrae were fixed on holders containing four markers each. The 3D reconstruction of both vertebrae and markers were obtained by stereoradiographic techniques. Using least square method matching from one position to another, the relative orientation was computed for the vertebral models (6 or 178 points) and the four markers. These vertebral and holder orientations were compared (considering the holder's one as reference). The repeatability of these relative orientations (vertebrae and holders) was also evaluated. The mean (RMS) orientation error of 178 point vertebral model was 0.6 degrees (0.8 degrees ), for lateral rotation, 0.7 degrees (1.0 degrees ) for sagittal rotation and 1.4 degrees (1.9 degrees ) for axial rotation. The intra-observer repeatability was 0.5 degrees (0.7 degrees ) for lateral rotation, 0.7 degrees (0.8 degrees ) for sagittal rotation and 0.9 degrees (1.2 degrees ) for axial rotation. The orientation was found more accurate and precise when using the 178 point vertebral model than when using the basic 6 point vertebral model. The relative orientation (in post-operative follow-up with respect to the pre-operative examination) of the vertebrae of one scoliotic patient was performed as an example of clinical application. The stereoradiographic method is a reliable 3D quantitative tool to assess the spine deformity, that can be used in clinics for the follow-up of scoliotic patients.

Intralesional Ethibloc injections in primary aneurysmal bone cysts: an efficient and safe treatment

OBJECTIVE

Ethibloc is a fibrogenic and thrombogenic agent recently proposed for the treatment of bone cysts. The purpose of this study is to report the results of direct Ethibloc injection in primary aneurysmal bone cyst (ABC) in children.

DESIGN AND PATIENTS

Seventeen patients, aged from 2 to 18 years (mean 8 years), were treated with either a single injection (14 patients) or supplementary injections (3 patients) of Ethibloc. The histological diagnosis was assessed following surgical biopsy and was retrospectively reviewed. The mean follow-up was 5 years (range 18 months to 11 years).

RESULTS

At 5 year follow-up, 14 of 17 patients demonstrated complete healing manifest by increased cortical and septal thickening. Surgical excision was required in three patients, in two of whom the ABC increased rapidly in size despite the injection, and in one of whom the healing was incomplete. We observed inflammatory reactions in 16 of 17 patients with local pain and fever. Three patients developed a small cutaneous fistula which resolved spontaneously in a few weeks. No major complications such as deep infection, pulmonary embolism, epiphyseal necrosis or malignant degeneration were observed.

CONCLUSION

Percutaneous direct Ethibloc injection is a safe, efficient and noninvasive treatment for ABC. The authors highlight the frequent local reactions.

[Imaging of the pediatric cerebellum]

After a brief overview of embryology, histogenesis, anatomy, as well as terminology, the authors will review the main acquired (neoplastic and non-neoplastic) and congenital (malformative and non-malformative) cerebellar pathologies through a pictorial essay. Even though there is some overlap, malformations are classified into agenesis, hypoplasia, and dysplasia, either cystic or non-cystic. Their embryological origin will be discussed. The main known syndromes associated with vermian agenesis will be reviewed. Non-neoplastic acquired cerebellar lesions, including atrophy and isolated signal anomalies, will be briefly reviewed. A classification of the main cerebellar malformations will be proposed.

[A peculiar form of neonatal adrenal insufficiency: the IMAGe association. Two new cases]

We report two siblings with an IMAGe syndrome. IMAGe is a newly reported syndrome characterized by the association of intra-uterine growth retardation, metaphyseal dysplasia, congenital adrenal hypoplasia and genital anomalies. This clinical association has only been described in five unrelated males. These two additional patients (one brother and one sister) suggest an autosomal recessive inheritance although identification of new cases will give further insight into the pathogenesis. The radiologic signs of osteopenia and metaphyseal dysplasia can suggest this diagnosis in affected individuals.

[Prenatal diagnosis of isolated posterior fossa anomalies: attempt at a simplified approach]

The authors suggest, after some embryological, anatomical and nosological reviews, a simplified approach mainly based on the appearance of the pons, cerebellar hemispheres and vermis, independently from an associated cystic dilatation of the posterior fossa. Pontocerebellar hypoplasias and partial or total vermian agenesis are detailed because they can be diagnosed with a prenatal MRI. This classification based on our experience and on the literature data should be of value to evaluate the neurological prognosis.

The AP diameter of the pelvis: a new criterion for continence in the exstrophy complex?

OBJECTIVE

Reconstructive surgery of bladder exstrophy remains a challenge. By using CT of the pelvis, we suggest a new pre- and post-operative investigative procedure to define the AP diameter (APD) as a predictive criterion for continence in this anomaly.

PATIENTS AND METHODS

Three axial CT slices were selected in nine children with exstrophy who had undergone neonatal reconstructive surgery. The three levels selected were the first sacral plate, the mid acetabular plane and the superior pubic spine. We used combined slices to measure: APD = distance between the first sacral vertebra and the pubic symphysis. Pubic diastasis (PD). Three angles defined on the transverse plane of the first sacral vertebra--iliac wing angle, sacropubic angle and acetabular version.

RESULTS

In exstrophy, the angles demonstrate opening of the iliac wings and the pubic ramus, and acetabular retroversion compared to controls. Comparisons between controls, continent and incontinent patients reveal that in continent patients, APD increases with growth and seems to be a predictive criterion for continence, independent of diastasis of the pubic symphysis.

CONCLUSIONS

We believe that CT of the pelvis with measurements of the APD should be performed in all neonates with bladder exstrophy before reconstructive surgery and for better understanding of the malformation. The APD seems to be predictive and may be a major criterion for continence, independent of PD.

Procalcitonin in children admitted to hospital with community acquired pneumonia

AIMS

To assess the sensitivity, specificity, and predictive value of procalcitonin (PCT) in differentiating bacterial and viral causes of pneumonia.

METHODS

A total of 72 children with community acquired pneumonia were studied. Ten had positive blood culture for Streptococcus pneumoniae and 15 had bacterial pneumonia according to sputum analysis (S pneumoniae in 15, Haemophilus influenzae b in one). Ten patients had Mycoplasma pneumoniae infection and 37 were infected with viruses, eight of whom had viral infection plus bacterial coinfection. PCT concentration was compared to C reactive protein (CRP) concentration and leucocyte count, and, if samples were available, interleukin 6 (IL-6) concentration.

RESULTS

PCT concentration was greater than 2 microg/l in all 10 patients with blood culture positive for S pneumoniae; in eight of these, CRP concentration was above 60 mg/l. PCT concentration was greater than 1 microg/l in 86% of patients with bacterial infection (including Mycoplasma and bacterial superinfection of viral pneumonia). A CRP concentration of 20 mg/l had a similar sensitivity but a much lower specificity than PCT (40% v 86%) for discriminating between bacterial and viral causes of pneumonia. PCT concentration was significantly higher in cases of bacterial pneumonia with positive blood culture whereas CRP concentration was not. Specificity and sensitivity were lower for leucocyte count and IL-6 concentration.

CONCLUSIONS

PCT concentration, with a threshold of 1 microg/l is more sensitive and specific and has greater positive and negative predictive values than CRP, IL-6, or white blood cell count for differentiating bacterial and viral causes of community pneumonia in untreated children admitted to hospital as emergency cases.

Technetium-99m HMPAO-labeled leukocyte imaging compared with endoscopy, ultrasonography, and contrast radiology in children with inflammatory bowel disease

BACKGROUND

The purpose of this study was to evaluate retrospectively the value of leukocyte-labeled scintigraphy, ultrasonography, and contrast radiography compared with endoscopy in children suspected of having inflammatory bowel disease (IBD).

METHODS

Twenty-eight children (17 boys; mean age, 10.2 years) with IBD based on standard colonoscopic, histologic, and radiologic criteria (16 with Crohn's disease, 5 with ulcerative colitis, 5 with nonspecific colitis, I with granulomatous disease, and I with Beh,cet's disease) were included. Endoscopic, ultrasonographic, and contrast radiologic examinations were realized for 28, 23, and 19 children respectively.

RESULTS

Sensitivity and specificity were 75% and 92% for leukocyte-labeled scintigraphy, 39% and 90% for ultrasonography, and 58% and 83% for contrast radiography. The authors noted discontinuous uptake for 14 of 15 true-positive results for patients with Crohn's disease and continuous uptake for 4 of 4 true-positive results for patients with ulcerative colitis. A negative correlation between scan activity index and Lloyd-Still clinical score was found for 11 patients with Crohn's disease (r = -0.77).

CONCLUSIONS

Leukocyte-labeled scintigraphy, a noninvasive and reproducible technique, is a useful tool in the diagnosis and therapeutic strategy of IBD, and provides information on the presence, the intensity, and the extent of the disease, particularly in the terminal ileum. Leukocyte-labeled scintigraphy may not replace colonoscopy with biopsies for diagnosis confirmation. Its reliability seems higher than that of ultrasonography.

[MRI of the brain in the evaluation of children with developmental delay]

PURPOSE

To analyze the diagnostic value of MRI in children with developmental delay. Materials and Methods. From 1991 to 1997, 224 examinations were performed. Retrospective analysis of clinical findings and diagnostic yield was carried out.

RESULTS

MRI was abnormal in 109 cases. It never resulted in any patient care modification. 55 malformations, 12 cases of cerebral atrophy, 7 cases of white matter disease and 2 patients with phakomatose were identified. Myelination delay (26 cases), increased signal of posterior white matter on T2-weighted images (9 cases) or widened Virchow-Robin spaces (3 cases) were frequently encountered, but it remained unclear whether they represented normal variants or true abnormalities. Post ischemic lesions were identified in 10 cases. Frequency of abnormal studies was significantly lower in children with developmental delay and behavioral disorders than in patients with other clinical presentation.

CONCLUSION

Diagnostic yield of cerebral MRI can justify its performance by comparison to other imaging modalities. It should be correlated with other investigations performed in a specialized unit. Its main interest is for classification and research. Risk of sedation or anesthesia should also be taken in account. Risk can be lowered using adequately equipped MR units and organizing procedures in collaboration with anesthesiologists.

Reduced lung diffusion capacity after Mycoplasma pneumoniae pneumonia

BACKGROUND

Mycoplasma pneumoniae is a frequent but underdiagnosed cause of community-acquired pneumonia (CAP) in children, and appropriate macrolide treatment is often given late. The aim of this work was to estimate the frequency of pulmonary involvement in children 6 months after a clinical episode of Mycoplasma CAP.

METHODS

We measured carbon monoxide diffusion capacity (TLCO) and conducted spirometric tests in 35 children without asthma or chronic lung disease (ages 4.5 to 15 years), 6 months and 1 year after acute CAP caused by M. pneumoniae (23 children), pneumococci (5 children) or viruses (7 children). Only 11 of 23 patients with M. pneumoniae CAP required hospitalization, whereas all the patients with pneumococcal or viral pneumonia were admitted to hospital.

RESULTS

Lung volumes and spirometric tests were normal for all children. TLCO was normal 6 months after pneumococcal or viral pneumonia (87 to 112% of expected values for height and sex). After acute M. pneumoniae CAP, 11 of 23 patients (48%) had TLCO values <80% of the expected value. The extent of change in lung diffusion capacity was correlated with the delay to diagnosis and treatment: TLCO was low in 8 of 11 patients given macrolide treatment 10 days or more after the onset of acute symptoms vs. only 3 of 10 patients given appropriate treatment in the first 10 days. TLCO was low in 7 of 7 who received macrolide therapy for <2 weeks. TLCO had increased slightly after 1 year in the 5 patients retested after a new course of macrolide treatment. TLCO reached the lower normal range in 2 patients controlled after 3 years.

CONCLUSIONS

The abnormal TLCO values suggest that some children with Mycoplasma pneumonia have reduced pulmonary gas diffusion after recovery from the illness. The reduction is related to delay and short macrolide therapy.

Rheumatological presentation of developmental bone diseases

Developmental bone disease may be present, with rheumatological disorders as the major symptoms, even in children. The major lesions encountered are early osteo arthritis, osteo chondromatosis and vertebral involvement with two leading types, pseudo Scheuermann's disease or pseudo ankylosing spondylitis. This paper presents the different features and lists the rheumatological problems in bone dysplasia.

[Radiologic anomalies of pseudohypoparathyroidism: diagnostic importance]

Pseudohypoparathyroidism is a congenital metabolic disorder which is often revealed by growth retardation. The diagnosis may be suggested by plain radiological findings such as short metacarpals, mainly the fourth, epiphyseal anomalies or subcutaneous calcifications. The following biological tests are mandatory to confirm this diagnosis: CaP workup and plasma level of PTH; urine cAMP measurement after PTH challenge; Evaluation of protein Gs activity In this study of 20 cases displays will be reviewed the different radiological findings seen in patients with PsHP and the relative value discussed, such as narrowing of the spinal canal and presence of bony findings of hyperparathyroidism.

Ischio-vertebral dysplasia: a distinct entity

BACKGROUND

Kyphoscoliosis is a complication of some bone dysplasias, including cleidocranial dysplasia.

OBJECTIVES

We report a distinct disorder with defective ossification of the ischial rami, severe kyphoscoliosis and normal clavicles. Early recognition of this syndrome allows prevention of complications.

MATERIALS AND METHODS

All patient cases (aged 1 day to 33 years) were selected according to the above criteria, with special attention to radiological findings, family history and follow-up (5-30 years).

RESULTS

In all eight patients, we observed the following: (a) Severe thoracic scoliosis of early onset and rapid progression, leading to rotatory dislocation. Spinal cord compression occurred in four cases with respiratory problems related to chest deformity. (b) Bilateral and symmetrical incomplete ossification of the ischial rami. (c) Peculiar facies with retrognathia. (d) Normal clavicles. Three patients were from the same family (grandmother, mother and daughter).

CONCLUSION

Ischio-vertebral dysplasia seems to represent a true entity, with radiological and genetic findings that make it distinct from cleidocranial dysostosis. The association of kyphoscoliosis and these pelvic abnormalities is specific for this condition. Neurological and respiratory complications can be avoided if the condition is recognised early and early treatment is instituted.

[Imaging in pediatric Herpes simplex virus type I encephalitis]

PURPOSE

The aim of this study was to describe radiological features of herpes simplex virus 1 encephalitis, rarely reported in children.

PATIENTS AND METHODS

We analyzed imaging findings in 10 children with biologically proven herpes simples virus 1 encephalitis.

RESULTS

Eight CT scans were performed before the second day of the clinical course, 6 CT and 6 MRI were performed after day 4. The initial CT scan was normal in half of the cases. Low densities and hemorrhagic lesions were seen in almost half of the cases. There was no abnormal contrast enhancement in this series.

DISCUSSION

After 4 days of infection, hemorrhagic lesions were seen in all cases. Unilateral thalamic involvement was observed in half of the children, in correlation with clinical recurrence of encephalitis. The diagnostic, histological and therapeutic significance of these thalamic involvements remains to be elucidated.

Focal cortical dysplasia and hemimegalencephaly: histological and neuroimaging correlations

BACKGROUND

The classification of cerebral cortical dysplasia is difficult and there are histological similarities between focal cortical dysplasia (FCD) and hemimegalencephaly. Objectives. To correlate the MR features and histological data of cortical dysplasias.

MATERIALS AND METHODS

The MR appearances of 17 brains were examined. According to the signal intensity within the pathological area on T2-weighted (T2-W) sequences we selected two groups.

RESULTS

Group 1 comprised ten patients with high signal in the dysplastic area on T2-W images. This group included five hemimegalencephalies, three frontal quadramegalencephalies, and one gyral dysplasia. The pathological hemisphere was reduced in size in one case. The cortex was thickened in all cases on T1-weighted (T1-W) images. There was loss of delineation between white matter (WM) and grey matter (GM) in all cases on both T1-W and T2-W sequences. The differential diagnosis with tumour, neoplastic-like malformation or polymicrogyria was questionable. Group 2 comprised seven patients presenting without increased signal within the dysplastic area on T2-W images. WM and GM were of similar signal intensity in six cases, and delineation between white and grey matter was absent in all cases. There were mild abnormalities on T1-W sequences in all cases. The dysplasias were limited to a lobe in five cases and a gyrus in two cases. In all cases, depiction of the malformation was a greater diagnostic problem than the differential diagnosis.

CONCLUSIONS

A constant MR sign in our series was the loss of delineation between WM and GM in the dysplastic area. This correlated well with the observed histological disorganisation. Markedly high signal within the dysplastic area seems to be related to myelin abnormalities rather than glial cell abnormalities.

Evaluation of a new low-dose digital x-ray device: first dosimetric and clinical results in children

BACKGROUND

A new low-dose digital X-ray device, based on Charpak's Nobel prize-winning multiwire chamber, enables the production of images at very low doses. Objectives. To present the first dosimetric and clinical results.

MATERIALS AND METHODS

The analysis was performed on 93 children with scoliosis and 47 undergoing pelvic radiography. The comparative study between conventional X-ray and the new technique focused on three points: (1) the dose delivered by each system (2) the diagnostic information provided by each system and (3) comparison of image quality criteria with European guidelines.

RESULTS

The mean ratio of conventional dose to that of the low-dose technique was 13.1 for the spinal examination and 18.8 for the pelvis. There was no significant difference in diagnostic information available from each modality, but there was a slight difference in quality criteria in favour of the conventional technique.

CONCLUSION

This new device allows spectacular dose reduction, consistent with adequate clinical information. Improvements of the prototype will lead to extension of potential indications and industrial development.

Etiology and response to antibiotic therapy of community-acquired pneumonia in French children

The aim of this study was to determine the etiologic agents associated with community-acquired pneumonia in 104 French children ages 18 months to 13 years. Potential respiratory pathogens were identified in 87 (85%) cases; these included respiratory syncytial virus in ten, other viruses in 20, Streptococcus pneumoniae in 14 and Mycoplasma pneumoniae (diagnosed by serologic procedures) in 43. Of 32 patients with Mycoplasma pneumoniae infection who were initially treated with beta-lactam antibiotics, 30 failed treatment. Recovery from mycoplasma infection occurred rapidly in patients treated with macrolide antibiotics (which included spiramycin in 31 patients, josamycin in 7, and erythromycin in 3); however, cough persisted in 12 patients for one month. The high frequency of Mycoplasma pneumoniae in children over 18 months of age must be considered when selecting an antibiotic for initial therapy.

Accelerated myelination in early Sturge-Weber syndrome: MRI-SPECT correlations

The prognosis of Sturge-Weber syndrome (SWS) is partly related to early occurrence of seizures but the diagnosis of this phakomatosis may be difficult during the 1st year of life. We have performed a retrospective study of seven patients with confirmed SWS (age 7 days to 3 months). None of the patients was asymptomatic at the time of the study. They all underwent MRI (T1 and T2 sequences) and single photon emission computed tomography (SPECT) at the same time. Regional cerebral blood flow was measured using xenon-133. In all cases, myelination appeared to be accelerated in the areas underlying the leptomeningeal angioma on both MRI sequences. In five cases, SPECT showed hyperperfusion in the damaged hemisphere. In one case, the SPECT was symmetrical and in another it showed hypoperfusion in the damaged hemisphere which was already atrophied. These data suggest that the accelerated myelination is not related to ischemia but to transient hyperperfusion. This MRI pattern can be helpful for the early diagnosis of SWS, which is of utmost importance for preventive antiepileptic treatment.

Hypomelanosis of Ito and brain abnormalities: MRI findings and literature review

We report the results of a 14-year retrospective study of brain MRI abnormalities in 12 pediatric patients presenting with hypomelanosis of Ito (HI). Miscellaneous brain abnormalities were found: one patient had a medulloblastoma, three had cortical malformations, and five demonstrated "minor" abnormalities such as dilated Virchow-Robin spaces or brain atrophy. We emphasize the polymorphism of brain abnormalities associated with HI.

Role of magnetic resonance imaging in the diagnosis and prognosis of growth hormone deficiency

OBJECTIVE

In patients with congenital GH deficiency (GHD), magnetic resonance imaging (MRI) has revealed morphological abnormalities such as pituitary hypoplasia, absence of the stalk and ectopia of the posterior pituitary (PPE). Our study was aimed at investigating the possible relationship between neuroradiological images and the presence of isolated GH or multiple pituitary hormone deficiency.

DESIGN

We studied 121 patients, aged 0.3-25 years, with isolated GHD (IGHD, 81 cases) or multiple pituitary hormone deficiency (MPHD, 40 cases). Of 81 IGHD patients, 50 were at prepubertal and 22 at pubertal age, while 9 had a delayed onset of puberty. Out of 40 MPHD patients, 25 were at prepubertal age and 15 at the age of puberty.

RESULTS

Pituitary hypoplasia, defined as a gland with a height of less than -2 SD for age, was observed more frequently in prepubertal (66%) than pubertal (18%) IGHD patients. It was also found in the majority of MPHD patients of prepubertal (76%) and pubertal age (80%), and of IGHD patients with delayed onset of puberty (100%). Mean +/- SEM pituitary height was significantly lower (P < 0.001) in both prepubertal IGHD (-2.70 +/- 0.20 SD) and MPHD children (-3.10 +/- 0.39 SD) than in IGHD patients with normal onset of puberty (-1.55 +/- 0.2 SD). A significantly greater pituitary height was observed in IGHD patients with normal onset of puberty (-1.55 +/- 0.20 SD) than in MPHD patients at the age of puberty (-4.38 +/- 0.61 SD, P < 0.001) and in IGHD subjects with delayed onset of puberty (-4.06 +/- 0.41 SD, P < 0.001). An important increase (P < 0.02) in the height of the pituitary gland was found in 6 of the 9 patients with delayed puberty when they were re-evaluated after completing their spontaneous pubertal development. The frequency of other MRI abnormalities (PPE, stalk transection) was significantly higher in MPHD patients than in IGHD patients (P < 0.001).

CONCLUSION

Our results confirm the usefulness of MRI in the evaluation of children affected by GH deficiency. The association of gland hypoplasia with other MR abnormalities could suggest the presence of multiple anterior pituitary deficiencies. Finally, puberty seems to play an important role in the increase of pituitary size in multiple pituitary hormone deficiency and isolated GH deficiency patients.

[Corpus callosum agenesis and parasagittal interhemispheric cyst]

We report the association of a corpus callosum agenesis with a parasagittal interhemispheric cyst, without cortical malformation. This rare malformation is related to an early disorder in embryogenesis. The importance of the anatomic abnormalities compared with the good clinical status is remarkable. MR findings avoid misdiagnosis with a medial interhemispheric cyst associated to corpus callosum agenesis in which the prognosis is unpredictable.

[Community-acquired pneumonia in children: importance of Mycoplasma pneumoniae infections and efficacy of antibiotics]

OBJECTIVES

Define a therapeutic management schema adapted to children with community-acquired pneumonia.

METHODS

A prospective survey was conducted in 104 children over 18 months of age with community-acquired pneumonia. The pathogen was isolated in 85% of the cases.

RESULTS

Viral infection alone was proven in 30 children (respiratory syncytial virus in 10). Pneumococci pneumonia was found in 12 patients; the isolated strains were sensitive to penicillin. Apyrexia was obtained in 11/12 cases with amoxicillin. Mycoplasma infections occurred in 42% of the cases (41 alone and in association with pneumococci in 2 cases). Pneumococci and mycoplasma infections could not be differentiated with standard radiography and laboratory tests. Initial treatment with beta lactamines was always unsuccessful in children with mycoplasma infections. Apyrexia was achieved when antibiotics were changed to macrolides.

CONCLUSION

Since lower respiratory tract infections due to pneumococci are much more severe than those due to mycoplasma, beta lactamines should be given as first intention treatment for children over 18 months with pneumonia. Macrolides should be given in case of failure because mycoplasma would then be the most probable infectious agent.

[Magnetic resonance imaging in pediatrics]

In this study, the authors present the problems related to MRI in children, mainly sedation. Main indications of this method in children are reported as well as the role compared to other imaging modalities. MRI is now a routine tool. Well oriented use of MRI remains consistent with the health expenses control and allows improvement of health care and shortens the diagnostic delays.

Alteration of lung diffusion capacity in IgA nephropathy

OBJECTIVE

To establish whether changes of lung transfer for carbon monoxide (TLCO) are related to the phase of IgA nephropathy.

METHODS

Respiratory function was tested in 12 children with IgA nephropathy assessed by percutaneous renal biopsy. This was done during acute exacerbations or haematuria-free phases of the disease.

RESULTS

TLCO was low in 12/13 measurements made in the haematuric phase of IgA nephropathy or during the month following gross haematuria (mean TLCO 64% of expected values). Lung volumes and blood gas values were normal and only minor radiological signs of interstial lung involvement were observed in 11/12 patients. When respiratory tests were performed more than three months after gross haematuria, TLCO was low in 4/9 patients, with no relation to the significance of residual proteinuria or severity of findings at renal biopsy. There was a significant difference between tests performed when haematuria was present or recent and those performed more than three months after an episode of gross haematuria (p < 0.01).

CONCLUSIONS

The decrease of TLCO in the acute phases of the disease is probably related to alterations of the lung alveolarcapillary membrane by immune complexes containing IgA. This non-invasive technique, easy to perform and repeat, could be of value in the diagnosis of IgA nephropathy in haematuric children.