Lumbar spinal cord motion measurement with phase-contrast MR imaging in normal children and in children with spinal lipomas

We assessed the normal movement of the lumbar spinal cord using phase-contrast MR imaging, and also the movement of the spinal cord in patients with spinal lipoma pre- and postoperatively. Phase-contrast MR imaging proved to be a valuable tool in this context.

Nesidioblastosis and persistent neonatal hyperinsulinism

Neonatal hyperinsulinism is characterized by severe hypoglycaemia which can cause serious neurologic effects. Pancreatic morphological abnormalities involve either focal or diffuse lesions. The former can be cured by resection, whereas the latter, of uncertain pathogenesis, often require subtotal pancreatectomy. We investigated various hypotheses in an effort to explain the origin of this latter form of hyperinsulinism. We determined that nesidioblastosis, long considered to be the basic structural lesion of the diffuse form of hyperinsulinism, is not specific and does not correspond to a continuous proliferation of endocrine cells. We found that an increase in beta-cell mass can be excluded since the volume density of beta cells is not systematically higher in hyperinsulinemic infants than in controls. The hypothesis of a decrease in D cells is attractive but should be considered with due caution since the decrease of the D-cell volume density observed in hypoglycaemic infants is inconstant. Finally, the notion of beta-cell functional abnormality seems the most likely explanation since a higher quantity of proinsulin was detected within the Golgi area by a specific antibody and abnormal nuclei with abundant cytoplasm were observed in some cells. These histological abnormalities can be observed during intraoperative morphological examination. Functional activity might also be evaluated by studying the messenger RNA of proinsulin.

[Chronic septic granulomatosis revealed by neonatal pulmonary aspergillosis]

BACKGROUND

Pulmonary aspergillosis is now the main cause of death in chronic granulomatous disease (CGD); it may occur before the age of one year and then often reveals CGD.

CASE REPORT

A male newborn was referred to hospital at 27 days of age for fever (39 degrees C), hemodynamic failure and biological inflammation syndrome caused by pulmonary infection. Chest CT scan revealed multiple and bilateral intraparenchymatous nodules. An open lung biopsy showed histiocystic granuloma with multinucleated giant cells. Culture of tracheal, bronchoalveolar lavage samples and lung biopsy grew positive for Aspergillus fumigatus. Impaired chemiluminescence production by neutrophils was detected, enabling the diagnosis of CGD. It was later confirmed by the study of neutrophils functions. The child recovered after 12 months of parenteral amphotericin B therapy.

CONCLUSION

A febrile multifocal pneumopathy occurring in infancy should lead to consider the possibility of CGD which may be confirmed by the chemiluminescence test.

Hyperinsulinism in children: diagnostic value of pancreatic venous sampling correlated with clinical, pathological and surgical outcome in 25 cases

Neonatal hypoglycemia represents an emergency of heterogeneous etiology. The occurrence of persistent hypoglycemia caused by hyperinsulinism has not been well established. Some authors claim that it may be more common than previously suggested. The diagnostic goal is to distinguish hyperinsulinemia from other causes of hypoglycemia because management strategies differ. The diagnosis of persistent hypoglycemia attributable to hyperinsulinism is made when insulin secretion is excessive or inappropriate (> 10 microIU/ml). Medical management includes frequent feeding, high hydrocarbon intake, glucagon, diazoxide, somatostatin or steroid treatment. In case of resistance to medical intervention, surgery consisting of subtotal pancreatectomy is performed to avoid neurological sequelae. However, pediatric organic hypoglycemia secondary to hyperinsulinism can be caused by either diffuse or focal pancreatic lesions. Differentiation between these two types of lesion is necessary since partial pancreatectomy can prevent diabetes. In this prospective study, pancreatic venous sampling (PVS) was evaluated for the preoperative localization of lesions in 25 children with hyperinsulinism and correlated with surgical, pathological and clinical outcome. PVS is the most accurate preoperative technique for localizing focal lesions in children. Besides being safe and effective, it has the great advantage of detecting focal secretion, thus reducing the need for extensive surgery.

Prenatal diagnosis of tuberous sclerosis. Use of magnetic resonance imaging and its implications for prognosis

Tuberous sclerosis (TS) is an autosomal dominant disorder with a high rate of de novo mutation. The real difficulty is to ascertain the diagnosis and to give the neurological prognosis in each case. Prenatal diagnosis of TS is generally based on ultrasonographic signs of multiple cardiac tumours, i.e. rhabdomyomas. Recent progress in magnetic resonance imaging (MRI) enables the diagnosis in a large proportion of cases based on typical brain lesions. It may have a role in the prenatal management of TS, although MRI images seem to underestimate the anatomical findings. Two cases in which TS was diagnosed prenatally are presented with reference to the value of MRI in the prenatal management and comparison with anatomical findings.

[Aneurysmal cyst of the mandible: radiologic approach and therapy of this benign tumor]

The authors present a case of mandibular aneurysmal bone cyst with emphasis on the radiological aspects. The presence of fluid-fluid levels on CT and MR images is highly suggestive of ABC especially where there is no evidence of solid lesion. These findings help narrow differential diagnoses before making a therapeutic decision.

[Characteristic aspects of vascular complications in renal transplantation in children]

In a series of 859 transplantations performed in children and adolescents from January 1973 to December 1992, vascular thrombosis accounted for 18% of all graft losses (2nd cause of graft failure), and 57% of early failures (within 2 months). Renal veins and arteries were equally affected. The young age of the donors and recipients constituted the main risk factor, thrombosis accounting for 40 and 37% respectively of all graft losses in donors and recipients < 5 years old. This explained the lower survival rate of these age groups after grafting, as reported in most published pediatric series. The prophylactic use of a low molecular weight heparin in high-risk grafts may help to decrease its incidence. A renal artery stenosis, located a few cm beyond the anastomosis in 2/3 of cases, was observed in 10% of grafts. Often severe hypertension (HBP) with cerebral complications, responsible for permanent sequelae in some cases, was the prominent symptom. Anti-hypertensive drug therapy was sufficient to control HBP in 40 cases out of 72, and in 10 of these, a spontaneous regression of the stenosis was remarked within a few months after repeated angiography. Transluminal angioplasty was used on 26 stenosis and was effective in 2/3 of cases; the recurrence rate, however, was 27%.

Serious childhood angiomas: unsuccessful alpha-2b interferon treatment. A report of four cases

Over a 4-year period, we managed four children with alarming haemangiomas (two cases of Kasabach-Merritt syndrome and two life-threatening haemangiomas). Systemic steroid therapy was ineffective. Other treatments (radiotherapy, anti-platelet drugs) were also ineffective in the Kasabach-Merritt patients. On the basis of recent reports on the effects of interferon on endothelial cells, we used alpha-2 interferon therapy, but obtained no response.

[Role of magnetic resonance imaging in non-neoplastic hypothalamo-hypophyseal pathology]

This study was designed to evaluate the diagnostic, therapeutic, and pathogenetic data provided by magnetic resonance imaging (MRI) in nonneoplastic hypothalamo-pituitary disorders. After determination of age-specific pituitary heights, 46 children with idiopathic growth hormone deficiency (GH peak < 8 ng/ml) were studied. Twenty-nine patients (group I) had pituitary stalk interruption syndrome and 17 (group II) had no anatomic abnormalities. Age-specific pituitary height was decreased by more than 2 SDs in all group I patients versus only 60% (10/17) of group II patients. The GH deficiency was transient in 4 of the 7 children with normal pituitary findings. Forty-seven girls with breast development before eight years of age were also studied: age-specific pituitary height was normal in all girls with premature thelarche and 68% of girls with mild form of central precocious puberty (CPP). Conversely, in 70% of girls with evolutive CPP, age-specific pituitary height was increased by more than 2 SDs. These data show that MRI is useful for the diagnosis of pituitary insufficiency and that multiple anterior pituitary deficiencies can be expected in patients with anatomic abnormalities. MRI is of diagnostic and prognostic usefulness in CPP and, therefore, is of assistance in making therapeutic decisions.

Doppler ultrasonography in the early postoperative evaluation of renal transplants in children

The renal ultrasonography (US) scans of 23 children who had recently undergone kidney transplantation were reviewed; the studies included Doppler US scanning of the arterial vessels at several levels. There were 43 studies for children whose postoperative course was normal; 16 studies were obtained during episodes of acute tubular necrosis and 21 during episodes of acute rejection. The upper limit of normal for the resistive index (RI) at the arcuate artery is higher (up to 0.79) for a pediatric renal transplant patient than for adults with normal kidneys, regardless of the age of the kidney donor. Therefore, elevation of the RI to 0.80 or higher or complete loss of diastolic flow always indicates a complication of transplantation. Abnormally high RI values were seen in patients with both acute tubular necrosis and acute rejection; however, the RI value as determined by US did not distinguish these two entities. In addition, in 7 cases of acute tubular necrosis and 12 of acute rejection the RI was normal (0.58 to 0.79).

Old renal transplants examined by Doppler ultrasonography

Twenty-four ultrasonography (US) studies of 21 renal transplants that had been in place for 1 to 19 (median 3) years were evaluated. The absolute resistive indices (RIs) determined during Doppler US at various arterial levels and the differences in RI between the levels did not correlate with the clinical diagnosis of chronic rejection. This study suggests that measuring RI values with Doppler US in people who received renal grafts as children does not currently contribute additional information for diagnosis or management.

Extraosseous spinal chordoma: radiographic appearance

The authors describe a chordoma arising within the soft tissues of the spinal canal (rather than from a vertebral body) in a 6-year-old boy. The lesion was entirely extradural as shown by CT and MR; this was confirmed at surgery.

Precocious puberty in girls: pituitary height as an index of hypothalamo-pituitary activation

The pituitary heights in 47 girls having breast development before 8 yr were measured by magnetic resonance imaging and compared to the normal values for age and to clinical and laboratory data. They were classified into 3 groups: 1) premature thelarche (PT), isolated breast development with plasma estradiol less than 74 pmol/L (8 cases); 2) mild form of central precocious puberty (CPP1) with an LH/FSH peak ratio after the LH-releasing hormone test less than 1 (22 cases); 3) classical form of CPP (CPP2) with an LH/FSH peak ratio greater than 1 (17 cases). All girls with CPP had breast and pubic hair development before 8 yr, accelerated growth velocity, and no intracranial lesion. The mean ages at breast development [7.2 +/- 0.4 (SE), 6.5 +/- 0.4, and 7.2 +/- 0.3 yr] and the mean times between breast development and magnetic resonance imaging evaluation (0.8 +/- 0.1, 0.8 +/- 0.2, and 0.9 +/- 0.1 yr) were similar in the 3 groups. The mean pituitary heights were 4.9 +/- 0.2 in PT, 5.1 +/- 0.2 in CPP1, and 6.2 +/- 0.2 mm in CPP2. They were not significantly different in PT and CPP1 but were significantly greater in CPP2 than in PT (P < 0.001) or CPP1 (P < 0.001). Individual values of pituitary height were compared to those of age-matched girls: they were greater than or equal to mean +/- 2 SD in 8% of PT, 32% of CPP1, and 70% of CPP2. In the CPP group, the pituitary height was correlated with the LH/FSH peak ratio [correlation coefficient (r = 0.52, P < 0.01] and plasma estradiol (r = 0.60, P < 0.01). Four patients with high pituitary height despite LH/FSH peak ratios less than 1 had an increase of their breast development within 1 yr. We conclude that the pituitary height is normal for age in girls with premature thelarche or a mild form of CPP. Conversely, pituitary height is in the pubertal range in girls with the classical form of CPP. Its correlation with LH/FSH peak ratio suggests that pituitary height reflects changes in the degree of hypothalamo-pituitary activation and may provide an indication of its future development. It may therefore help in decisions on LH-releasing hormone analog therapy in certain cases.

[The value of CT and MRI in the assessment of basal encephaloceles in children]

Basal cephaloceles of the child are rare pathologies which require accurate preoperative imaging work-up. The CT and MR studies of six children with surgically proven basal cephalocele were retrospectively reviewed to evaluate the role of CT and MR in the preoperative work-up of a basal cephalocele of the child. In five patients, MR allowed to define the nature and topography of the cephalocele, and allowed an accurate depiction of the optic tract, ante- and post-hypophysis and associated agenesis of corpus callosum when present. 3-D CT allowed in one case a more precise depiction of the basal bony defect. MRI allows in a non invasive and non ionising way the best depiction of herniating meninges, brain or ventricles as well as associated cerebral anomalies.

[Kasabach-Merritt syndrome in children]

Kasabach-Merritt syndrome is a combination of thrombocytopenia, intravascular coagulation, and a rapid increase in the size of an angioma. Anemia and disseminated intravascular coagulation may develop. This infrequent syndrome is severe and may be life-threatening. Pathophysiologic mechanisms underlying the condition are incompletely understood and, consequently, many different treatments are used, including systemic corticosteroids, compression, embolization, antifibrinolytic agents, platelet aggregation inhibitors, irradiation, and others. From findings in eight personal cases, the authors review clinical and biological features, pathophysiologic hypotheses and therapeutic strategies.

Magnetic resonance imaging in the diagnosis of growth hormone deficiency

Forty-six patients with idiopathic growth hormone deficiency were examined by magnetic resonance imaging at a mean (+/- SEM) age of 9 +/- 1 years (range 15 days to 20 years). They were classified into two groups according to MRI images: group 1 (n = 29) had pituitary stalk interruption syndrome and group 2 (n = 17) had normal pituitary anatomy. All patients with pituitary stalk interruption had a pituitary height at less than -2 SD for age; three had no visible anterior pituitary lobe. By contrast, the pituitary height was less than normal in only 10 patients (60%) with normal pituitary anatomy. Growth hormone deficiency was transient in one of the seven patients with normal pituitary anatomy and height. The group with pituitary stalk interruption had the first symptom of growth hormone deficiency at an earlier age (2.8 +/- 0.6 vs 5.5 +/- 1.2 years; p less than 0.001), were of smaller stature (-4 +/- 0.2 vs -3 +/- 0.2 SD; p less than 0.01) and had lower GH peak response to provocative testing (3 +/- 0.4 vs 5 +/- 0.5 ng/ml; p less than 0.001) than did the group with normal pituitary anatomy. Their pituitary gland was also shorter (2.5 +/- 0.2 vs 3.5 +/- 0.2 mm; p less than 0.01). All the patients with multiple pituitary deficiencies except one (n = 19) belonged to this group. One girl with pituitary stalk interruption and deficiencies in growth hormone and thyroid-stimulating hormone had advanced central precocious puberty. We conclude that the evaluation of the shape and height of the pituitary gland by MRI is an additional tool for the diagnosis of growth hormone deficiency. The presence of pituitary stalk interruption confirms this diagnosis and is predictive of multiple anterior pituitary deficiencies. The lack of a significant increase in perinatal abnormalities in this group and the association of pituitary stalk interruption with microphallus and with facial or sella abnormalities suggest that this appearance may have an early antenatal origin. The finding of a familial case of pituitary stalk interruption suggests a genetic origin.

Neuroradiological findings in Sturge-Weber syndrome (SWS) and isolated pial angiomatosis

In 14 children with Sturge-Weber syndrome, cortical calcifications on CT scan was present in 12, localized brain atrophy in 10, enlargement of the choroid plexus in 7, and abnormal veins in 7. Cortical enhancement was present on 12 CTs performed shortly after an episode of severe seizures or hemiplegia but was absent or considerably less marked at a distance from the acute episodes. We suggest that cortical enhancement is related to seizure activity and/or blood-brain disturbances rather than to the extension of pial angioma.

Height of normal pituitary gland as a function of age evaluated by magnetic resonance imaging in children

MR anatomy of hypothalamo-hypophyseal axis is well established. However data about pituitary gland height (PGH) in children are sparse. A retrospective study was therefore performed in 60 children (30 boys and 30 girls) aged from 8 days to 21 years. All these children had MR for various neurological diseases. Patients with hypothalamo-hypophyseal disease and intracranial hypertension were excluded. The PGH was measured on a strict midline sagittal T1 weighted scan 3 to 7 mm thick. A positive linear correlation was found in children aged from 1 year to puberty followed by a plateau. In the first year of life a negative linear correlation was found. A positive linear correlation was found between PGH and statural height as well.

MR appearances of bone marrow in children following bone marrow transplantation

Two cases are presented of children who demonstrated complete absence of bone marrow signal on MR imaging of the spine following bone marrow transplantation. The possible causes for these appearances are discussed.

Modified Blalock Taussig shunt anastomosis in a three month old child with pulmonary stenosis: embolization therapy

A case of transcatheter occlusion of a modified Blalock-Taussig (BT) shunt with a detachable balloon is described. A three month old boy with pulmonary atresia with intact ventricular septum had a repair consisting in valvotomy and a modified BT. This palliative aorticopulmonary shunt created congestive heart failure. As an alternative to surgery, a detachable balloon was used to occlude the BT shunt.