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.