Whole-body MR imaging in suspected physical child abuse: comparison with skeletal survey and bone scintigraphy findings from the PEDIMA prospective multicentre study

OBJECTIVES

To assess the contribution of whole-body magnetic resonance imaging (WBMRI) and bone scintigraphy (BS) in addition to skeletal survey (SS) in detecting traumatic bone lesions and soft-tissue injuries in suspected child abuse.

METHODS

In this prospective, multicentre, diagnostic accuracy study, children less than 3 years of age with suspected physical abuse were recruited. Each child underwent SS, BS and WBMRI. A blinded first review was performed in consensus by five paediatric radiologists and three nuclear medicine physicians. A second review investigated discrepancies reported between the modalities using a consensus result of all modalities as the reference standard. We calculated the sensitivity, specificity and corresponding 95% confidence interval for each imaging modality (SS, WBMRI and BS) and for the combinations [SS + WBMRI] and [SS + BS].

RESULTS

One hundred seventy children were included of which sixty-four had at least one lesion. In total, 146 lesions were included. The sensitivity and specificity of each examination were, respectively, as follows: 88.4% [95% CI, 82.0-93.1] and 99.7% [95% CI, 99.5-99.8] for the SS, 69.9% [95% CI, 61.7-77.2] and 99.5% [95% CI, 99.2-99.7] for WBMRI and 54.8% [95% CI, 46.4-63.0] and 99.7% [95% CI, 99.5-99.9] for BS. Sensitivity and specificity were, respectively, 95.9% [95% CI, 91.3-98.5] and 99.2% [95% CI, 98.9-99.4] for the combination SS + WBMRI and 95.2% [95% CI, 90.4-98.1] and 99.4% [95% CI, 99.2-99.6] for the combination SS + BS, with no statistically significant difference between them.

CONCLUSION

SS was the most sensitive independent imaging modality; however, the additional combination of either WBMRI or BS examinations offered an increased accuracy.

KEY POINTS

• SS in suspected infant abuse was the most sensitive independent imaging modality in this study, especially for detecting metaphyseal and rib lesions, and remains essential for evaluation. • The combination of either SS + BS or SS + WBMRI provides greater accuracy in diagnosing occult and equivocal bone injuries in the difficult setting of child abuse. • WBMRI is a free-radiation technique that allows additional diagnosis of soft-tissue and visceral injuries.

T1-weighted dynamic contrast-enhanced brain magnetic resonance imaging: A preliminary study with low infusion rate in pediatric patients

Background The aim of this preliminary study is to evaluate the results of T1-weighted dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) in pediatric patients at 1.5T, with a low peripheral intravenous gadoteric acid injection rate of 1 ml/s. Materials and methods Children with neurological symptoms were examined prospectively with conventional MRI and T1-weighted DCE MRI. An magnetic resonance perfusion analysis method was used to obtain time-concentration curves (persistent pattern, type-I; plateau pattern, type-II; washout pattern, type-III) and to calculate pharmacokinetic parameters. A total of two radiologists manually defined regions of interest (ROIs) in the part of the lesion exhibiting the greatest contrast enhancement and in the surrounding normal or contralateral tissue. Lesion/surrounding tissue or contralateral tissue pharmacokinetic parameter ratios were calculated. Tumors were categorized by grade (I-IV) using the World Health Organization (WHO) Grade. Mann-Whitney testing and receiver-operating characteristic (ROC) curves were performed. Results A total of nine boys and nine girls (mean age 10.5 years) were included. Lesions consisted of 10 brain tumors, 3 inflammatory lesions, 3 arteriovenous malformations and 2 strokes. We obtained analyzable concentration-time curves for all patients (6 type-I, 9 type-II, 3 type-III). K^trans between tumor tissue and surrounding or contralateral tissue was significantly different ( p = 0.034). K^trans ratios were significantly different between grade I tumors and grade IV tumors ( p = 0.027) and a K^trans ratio value superior to 0.63 appeared to be discriminant to determine a grade IV of malignancy. Conclusions Our results confirm the feasibility of pediatric T1-weighted DCE MRI at 1.5T with a low injection rate, which could be of great value in differentiating brain tumor grades.

Prenatal findings in carpenter syndrome and a novel mutation in RAB23

Carpenter syndrome is caused by mutations of the RAB23 gene. To date, 12 distinct mutations have been identified among 34 patients from 26 unrelated families. We report on the prenatal findings in a fetus with Carpenter syndrome with a novel RAB23 mutation. Cystic hygroma, bowed femora, abnormal skull shape and a complex heart defect were seen on ultrasound scan, and Carpenter syndrome was diagnosed at birth. Craniosynostosis and preaxial hexadactyly of the feet were retrospectively detectable on the fetal CT scan. Sequencing of RAB23 identified a homozygous mutation leading to skipping of exon 6 and premature termination codon (c.481G>C; p.Val161Leufs*16). This observation illustrates the difficulty of prenatal ultrasound diagnosis of Carpenter syndrome. To our knowledge, this diagnosis was suggested on ultrasound scan in only one prior patient, although in five other patients abnormal skull shape and variable findings, mainly limb anomalies including bowed femora in one case, were described during the pregnancy. Heart defect and bowed femora are rare postnatal findings. The diagnosis of Carpenter syndrome should therefore be considered on prenatal imaging in cases of bowed femora and/or cardiac defect associated with abnormal skull shape.

Repères échographiques de gyration cérébrale fœtale normale

PURPOSE

Define normal sulcation patterns and their chronological order of appearance on transabdominal ultrasound by comparing them with brain maturation references available in fetopathological studies and MRI findings.

PATIENTS AND METHODS

By means of a prospective study, 158 normal fetal brains aged 21 to 34 gestational weeks have been analyzed with standardized data by transabdominal ultrasound in eleven different views using axial, coronal and sagittal orientation.

RESULTS

The sequential development of cerebral sulci has been described according to the gestational age. This chronology was consistent with anatomo-pathologic references presenting a mean late period of one week and with MRI but without any late period. This study is available on the following website:

CONCLUSION

This ultrasound study provides accurate landmarks and imaging features of normal fetal brain sulcation. The analysis and the knowledge of this sulcation provide better understanding of the brain cortex maturation and may be helpful in diagnosing brain diseases.

[Value of fetal cerebral magnetic resonance imaging for the prenatal diagnosis and prognosis of corpus callosum agenesis]

OBJECTIVE

To evaluate MR contribution to prenatal diagnosis and prognosis of corpus callosum agenesis suspected by ultrasound and to ascertain how and when this examination should be included part in prenatal management of such malformation.

PATIENTS AND METHODS

During a six-year period from January 1st 1994 and December 31st 2000, fifteen patients (and fifteen fetuses) were referred to our fetal medicine unit with suspicion of corpus callosum agenesis on prenatal ultrasound. Cerebral MRI was performed in all cases to confirm prenatal diagnosis. In our study, prenatal MRI examinations were retrospectively studied and compared with neuropathological examinations (n=8) or postnatal imaging (n=6).

RESULTS

Corpus callosum agenesis were either complete (n=13) or partial (n=1). All were visible on prenatal MRI but only six on prenatal ultrasound. In one case, ultrasound suspicion of corpus callosum agenesis was ruled-out (false positive on prenatal ultrasound) by fetal cerebral MRI. In five cases corpus callosum agenesis was an isolated finding whereas in 12 cases associated malformations were encountered (cerebral n=7 or extra-cerebral n=5). MR depicted 7 of the 12 associated neurologic abnormalities.

CONCLUSION

Prenatal MRI is a valuable complementary technique for either diagnosis of corpus callosum agenesis and depiction of associated neurologic abnormalities. Superiority of MR on prenatal sonography and its help in post-mortem examination of the brain (help in the choice of the pathologic technique and localisation of the samples) makes it essential even when pregnancy termination is considered.

Prenatal diagnosis and early in utero management of fetal dyshormonogenetic goiter

We present a case of a fetal dyshormonogenetic goiter diagnosed by ultrasound examination at 24 weeks of gestation, in a woman with no past history of thyroid disease or goitrogen treatment and with normal thyroid tests, including absence of auto-antibodies. In this situation, fetal goiter may only be associated with fetal hypothyroidism, therefore cord blood sampling was not performed but early treatment was initiated. Amniotic fluid instillation of thyroid hormone led to a rapid decrease in amniotic fluid volume and a clear reduction in thyroid goiter. However, fetal thyroid volume did not totally normalise, and cord blood analysis at birth showed elevated fetal TSH level. As prenatal treatment of fetal hypothyroidism remains controversial in euthyroid mothers, the main objective is to prevent obstetrical complications of large goiters. Therefore, in some selected cases with no maternal history of thyroid disease and normal thyroid function tests, cordocentesis is not necessary to confirm fetal thyroid status or to adjust fetal treatment.

Fetal ovarian cysts: a report of three cases managed by intrauterine aspiration

Small follicular or functional theca-lutein cysts are a common finding in fetal and neonatal ovaries. After delivery, decrease of hormonal stimulation may lead to spontaneous resolution of the cyst. A high rate of complication has been underlined by recent studies, the most common being ovarian torsion with subsequent loss of the ovary. Because torsion may happen with any size of cyst, however large or small, we suggest in utero decompression even in small fetal ovarian cysts (< 5 cm). We report here three cases of such cysts managed by intrauterine aspiration with good outcome and no further need for neonatal surgery. In all cases cytology of the cyst aspirate demonstrated numbers of granulosa cells and fluid biochemistry showed a high amount of estradiol, progesterone, and testosterone that confirmed the etiology as ovarian. Despite the small size of the cysts, no technical difficulties were encountered and no maternal or fetal morbidity occurred. Prenatal management of fetal ovarian cysts remains controversial, however, and our limited experience needs to be assessed on a larger number of cases.