J. Tröger

Normative values for intima-media thickness and distensibility of large arteries in healthy adolescents.

Objective Sonographic evaluation of arterial wall morphology and elasticity is increasingly accepted as a non-invasive tool in cardiovascular assessment. Several studies suggest that intima–media thickness (IMT) and arterial elasticity indices may sensitively reflect different vasculopathic processes in children. However, normative values and the impact of adolescent growth are largely unknown. Methods We assessed the IMT of the common carotid (cIMT) and femoral arteries (fIMT), carotid elasticity indices and interacting anthropometric factors in 247 healthy subjects aged 10–20 years. Results cIMT, fIMT, incremental elastic modulus (Einc) and circumferential wall stress (CWS) were positively, and distensibility coefficient (DC) inversely, correlated with age, height, body mass index (BMI), systolic blood pressure (BP) and brachial pulse pressure (r = 0.56 to −0.45, P < 0.05 to 0.0001). DC (r = −0.29, P < 0.0001) and stiffness index β (r = 0.25, P < 0.0001), but not Einc, were significantly associated with cIMT independently of age. All vascular parameters showed non-Gaussian distributions. Excessively high IMT was associated with BMI and pulse pressure above the 90th percentile, and elevated Einc with high-normal BMI. Multivariate analysis identified independent positive effects of standardized BMI and brachial pulse pressure on normalized cIMT, negative effects of systolic BP and cIMT on DC, a positive effect of cIMT on stiffness, and positive effects of systolic BP and BMI on Einc and CWS. Conclusions Morphological and functional measures of large arteries should be normalized to take account of changes during adolescence and skewed distributions. Relative body mass, systolic blood pressure and/or pulse pressure are determinants of IMT and elasticity.

Combined static-dynamic MR urography for the simultaneous evaluation of morphology and function in urinary tract obstruction. I. Evaluation of the normal status in an animal model.

Objective. A new approach, combined static-dynamic MR urography is evaluated to determine its potential utility for the functional-morphological diagnosis of paediatric urinary tract obstruction. In this initial investigation we sought to evaluate the procedure by imaging the urinary tract of piglets. Materials and methods. Twenty-nine healthy piglets were studied with MR urography (MRU), 99 mTc-MAG3 diuretic renal scintigraphy (DRS), ultrasound (US) and excretory urography (EU). The functional and morphological findings were compared. For MRU we combined a respiration-triggered 3D-IR-TSE sequence and a dynamic 2D-FFE sequence after Gd-DTPA injection. Results. MRU depicted the complete urinary tract with superior image quality compared to EU. Calculation of time-intensity curves from the dynamic sequence permitted determination of single kidney function from parenchymal ROIs and urinary excretion using the whole kidney ROI. MRU and DRS showed significant agreement in the assessment of both single kidney function and urinary excretion. Disturbances of urinary drainage were generally caused by an overfilled bladder. Conclusions. Combined static-dynamic MRU is well suited for the depiction of the complete urinary tract and for the determination of individual kidney function and urinary excretion in the piglet.

Current radiological management of intussusception in children

Intussusception is the most common abdominal emergency situation in infants and small children. There has been great progress in diagnostic and therapeutic management of intussusception. Ultrasound (US) has been shown to be the first-choice imaging technique in diagnosing intussusception for reasons of high accuracy, simultaneous exclusion of differential diagnoses, and disclosure of additional pathologies. Controversial opinions exist worldwide concerning the nonoperative treatment of intussusception in infants and children. Pneumatic reduction under fluoroscopic guidance and hydrostatic reduction under US monitoring are the preferred techniques. The aim should be a success rate of at least 90% in idiopathic intussusception. This review summarizes different types of intussusception and outlines diagnostic aspects as well as several treatment concepts.

Combined static-dynamic MR urography for the simultaneous evaluation of morphology and function in urinary tract obstruction. II. Findings in experimentally induced ureteric stenosis.

Purpose. To assess the diagnostic value of combined static-dynamic MR urography (MRU) for the functional-morphological evaluation of experimentally induced urinary tract obstruction in the piglet. Materials and methods. In 20 piglets unilateral ureteric stenosis was created operatively. Post-surgery repeated comparative examinations were obtained with MRU, diuretic renal scintigraphy (DRS), excretory urography (EU) and ultrasound (US). MRU was performed as a combination study with a static 3D-IR-TSE sequence and a dynamic 2D-FFE sequence after Gd-DTPA with frusemide administration. Results. MRU allowed complete depiction of the prestenotic urinary tract and of the stenosis in all cases. In 43 comparative studies MRU was superior to EU in 36, EU to MRU in 2. When single kidney function was calculated with both MRU and DRS, results were highly correlated (r = 0.92). When urinary excretion was compared, significant agreement was achieved with concordant findings in 86 % and slightly discordant results in 12 %. Conclusions. Static-dynamic MR urography permits excellent depiction of experimentally induced urinary tract obstruction in piglets and reliable assessment of individual renal function and urinary excretion. Two advantages of the method stand out – it does not require radiation and it permits functional-morphological correlation.

Hydrostatic reduction of intussusception under US guidance

The current nonoperative management of ileocolic intussusception includes hydrostatic and pneumatic reduction, both performed under fluoroscopic monitoring. Recently, a new technique — ultrasoundguided reduction — replaced the conventional approach in our institution. Over a 20-month period, 46 intussusceptions were diagnosed sonographically in 40 patients. In all cases, reduction was attempted under ultrasound guidance by means of a normal saline enema. In 42 cases (91%) reduction was successful and only four patients had to be operated (two resections, two manual reductions). Complications did not occur. this technique permits distinct visualization of the entire process, providing a clear and detailed echogram of the fluid-filled large and small intestine. We established the following definite criteria of reduction: disappearance of the target, demonstration of the ileocecal valve, visualization of the fluid reflux, and fluid filling of small bowel loops. The presented technique for the reduction of intussusception without radiation exposure is reliable and safe, and appears to be one of the most promising methods for the nonoperative treatment of ileocolic intussusception.

The conus medullaris: time of ascendence to normal level

This study was intended to determine the level of the conus medullaris in normal babies. We examined 114 healthy infants using high resolution ultrasound which identified the spinal cord and the tip of the conus medullaris. This method provided a good analysis of the level of the conus medullaris so that we could assess the rate of ascent to L1/2. The range of the conus level for all children was at TH12/L1 interspace to L4.78% of babies aged between the 30th and 39th postmenstrual week had the tip of the conus medullaris between L2 and L4. 84% of babies aged between the 40th and 63rd postmenstrual week had their conus level between TH12/L1 and L1/2 interspace. In one girl aged 53 weeks the tip was found at L4. Ultrasound is a reliable method to observe the development of the conus level in young infants and to identify a tethered cord.

MR to assess renal function in children

Abstract.Renal function evaluation in the pediatric patient is generally based on scintigraphic examinations where a baseline gamma-camera renography is used to determine single kidney function, and diuresis renography is obtained to assess urinary drainage from the pelvicalyceal system. Magnetic resonance imaging also permits the evaluation of renal functional processes using fast dynamic sequences. Principally, an agent cleared by renal excretion is intravenously injected and its cortical uptake, parenchymal transport, and eventually its urinary excretion are followed with serial images. Different approaches have been presented most of which are based on T1-weighted gradient-recalled echo sequences with short TR and TE and a low flip angle obtained after intravenous injection of Gd-DTPA or Gd-DOTA. These techniques permit renal functional assessment using different qualitative and quantitative parameters; however, most of these methods are not suitable for the evaluation of urinary tract dilatation in infants and children. For the diagnostic work-up of children with congenital urinary tract obstruction and malformation a technique was developed which permits quantitative determination of single kidney function, in addition to evaluating urinary excretion disturbances analogous to that possible with scintigraphy.

Glutaric aciduria type I: ultrasonographic demonstration of early signs

Background. Glutaric aciduria type I (GA-I) is a rare inherited metabolic disease with increased excretion of glutaric acid and its metabolites. Diagnosis is often delayed until the onset of irreversible neurological deficits. Material and methods. We reviewed the clinical and imaging (US, CT and MRI) findings in six patients with proven GA-I and with emphasis on the early US findings. Coronal and sagittal US images of the brain were obtained through the anterior fontanelle in all patients. CT was obtained in three patients and MRI was obtained in two. Results. Macrocephaly was found in all patients, being present in three children at birth or developing rapidly within the first weeks of life. US showed, in all patients, bilateral symmetrical cyst-like dilatation of the sylvian fissures. Progressive fronto-temporal atrophy developed within the first months. CT and MRI demonstrated fronto-temporal atrophy with lack of opercularisation in all cases and basal ganglia or periventricular hypodensities in three patients. Conclusions. In patients with macrocephaly at birth or rapidly developing within the first weeks of life, US should be performed as the primary imaging modality. Cyst-like bilateral widening of the sylvian fissures is the first sign of GA-I, followed by progressive fronto-temporal and ventricular enlargement. These patients should be screened for GA-I in order to initiate treatment in the asymptomatic stage.

Ovarian cysts in the fetus and neonate—changes in sonographic pattern in the follow-up and their management

In a multicenter trial we retrospectively evaluated the clinical and sonographic data of 49 neonatal ovarian cysts, 44 of which were detected prenatally and 5 on the first day after delivery. Of the 44 prenatally detected cysts 39 were purely cystic, 5 echogenic or had a mixed pattern. In 20 patients the cystic appearance changed during delivery from purely cystic to a mixed pattern being independent on the size of the cyst. 26 of the 44 cysts were treated surgically. Salpingotorsion was found in 8 and was independent on the size of the cyst. In 15 a salpingo-oophorectomy or oophorectomy was performed, in 11 the ovary was saved. 23 patients were followed sonographically: 15 cysts showed complete resolution within 14 months without correlation to the sonographic pattern. The volume of these cysts varied between 5 and 71 ml. Neonatal ovarian cysts disappear spontaneously frequently and rarely cause severe symptoms. The authors recommend follow-up by ultrasound as the primary modality. Surgical intervention is recommended only if the cyst is space-occupying and percutaneous puncture can not be performed or in the case of emergency.

Pyloric muscle in asymptomatic infants: sonographic evaluation and discrimination from idiopathic hypertrophic pyloric stenosis

Objective. To compare the morphological and functional US appearance of the pylorus in healthy infants with those suffering from idiopathic hypertrophic pyloric stenosis (IHPS) in order to determine the pathological limits and to find out the most discriminating morphometric parameter. Materials and methods. The pylorus of 84 asymptomatic infants was prospectively evaluated with respect to morphology (pyloric length, pyloric diameter, muscle thickness and pyloric volume) and function (gastric peristalsis and emptying, pyloric opening and the fluid passage). Results were compared with 85 patients with proven IHPS. Results. In every normal infant we observed frequent pyloric opening with passage of gastric contents and quick gastric emptying. All infants with proven IHPS presented with a permanently closed pylorus and exaggerated, retrograde gastric peristalsis. For each of the four parameters, highly significant differences (P < 0.0001) were found between the control and IHPS groups. Pathological limits were 3 mm for muscle thickness (accuracy 100 %), 15 mm for pyloric length (accuracy 94 %), 11 mm for pyloric diameter (accuracy 92 %) and 12 ml for pyloric volume (accuracy 96 %). Conclusions. Evaluation of pyloric function plays an important role in the diagnosis of IHPS. The morphometric parameters are highly accurate in differentiating IHPS from a normal pylorus, muscle thickness being the most discriminating parameter.