Search PubMed⌕ Search

Biomedical subjects

J Tröger

Publications and source records attributed to J Tröger.

At least 37 records · Page 2Linked to original sources
PubMed1999

Léri-Weill syndrome as part of a contiguous gene syndrome at Xp22.3.

We report on a mother and her 5-year old son, both with a terminal deletion of the short arm of the X chromosome. By molecular genetic analysis the breakpoint was located distal to steroid sulfatase gene. The boy manifested, due to nullisomy of this region, short stature (SHOX), chondrodysplasia punctata (ARSE), and mental retardation (putative mental retardation gene MRX 49). Short stature is present in mother and son, but both also had bilateral Madelung deformity, a key finding in the Léri-Weill syndrome. We discuss the phenotype in relationship to hitherto published cases with chromosomal aberrations and contiguous gene syndromes of Xp22.3.

Abnormalities, Multiple↗
PubMed1999

[Diagnostic imaging of the kidneys and the urinary tract in children].

Imaging flow charts differ in pediatric and general radiology. The reasons are: different illnesses, different consequences arising out of imaging results and different sequence of imaging methods. Ultrasound is always the first imaging method of the urinary tract in infancy and childhood starts with ultrasound with the exception of severe abdominal trauma which is investigated by computer-tomography. The decision "normal or abnormal" is possible using ultrasound in the most pediatric cases. The diagnostic value and significance of ultrasound in infancy and childhood is far better than in general radiology because of the higher resolution of the high-frequency units taken. The result of the ultrasound examination should be the basis for the following imaging procedures. We will describe diagnostic flow charts starting with three important clinical symptoms: Prenatal pathology, urinary tract obstruction and urinary tract infection.

Age Factors↗
PubMed1999

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.

Abnormalities, Multiple↗
PubMed1999

Randomized comparison of high-frequency ventilation with high-rate intermittent positive pressure ventilation in preterm infants with respiratory failure.

OBJECTIVE: In a randomized, controlled, multicenter trial, we tested the hypothesis that high-frequency ventilation (HFV) with a high lung volume strategy results in fewer treatment failures than intermittent positive pressure ventilation (IPPV) with high rates and low peak inspiratory pressures. STUDY DESIGN: Infants with a gestational age between >/=24 weeks and <30 weeks, requiring mechanical ventilation within 6 hours of birth, were randomly assigned to receive either IPPV or HFV until 240 hours after randomization, extubation, or meeting treatment failure criteria. Treatment failure, the primary end point, was determined when air leaks, an oxygenation index >35 to 45 (depending on gestational age), death, or chronic lung disease occurred. Chronic lung disease was defined as persistent requirement of mechanical ventilation, continuous positive airway pressure, or supplemental oxygen at a postmenstrual age of 36 weeks. Secondary end points included the incidence of intracranial hemorrhage. RESULTS: The third scheduled interim analysis led to termination of the trial after recruitment of 284 infants. Treatment failure criteria were met by 46% of infants receiving IPPV and 54% of infants receiving HFV (1-tailed primary hypothesis, P =.92; 2-tailed chi2 test, P =.15). Air leaks occurred in 31% and 42% (P =.042), CLD in 23% and 25%, and grade 3-4 intracranial hemorrhage in 13% and 14% of IPPV-treated and HFV-treated patients, respectively. The mortality rate before discharge was 10% in both groups. CONCLUSION: HFV with a high lung volume strategy did not cause less lung injury in preterm infants than IPPV with a high rate and low peak inspiratory pressures.

Bronchopulmonary Dysplasia↗
PubMed1999

Effect of iodine supply on neonatal thyroid volume and TSH.

A cross-sectional study was performed to prove the correlation between iodine intake and neonatal thyroid volume in a randomized group of 100 mother/newborn pairs. Thyroid volume and iodine excretion were measured by ultrasound and urinary iodine excretion, respectively. Iodine intake and, nutritional and smoking habits were estimated by questionnaire. In 89 mother/child-pairs the data were complete for all parameters and have been analyzed: 32 mothers substituted with iodine tablets, average dose 175 microg K-Iodide/day. Iodine excretion of prenatally iodine-substituted newborns increased by 62% whereas neonatal thyroid volume was reduced by 18% compared with the non-iodine-supplemented group. Smoker's newborns (n = 8) had a thyroid volume 20% larger than that of newborns of non-smokers. Neonatal TSH-screening values remained within normal limits.

Cross-Sectional Studies↗
PubMed1999

[The quality of the care of children and adolescents within the realm of conventional x-ray diagnosis--a pilot study].

PURPOSE: The aim of the study was to evaluate the current quality of the outpatient radiodiagnostic care of children and adolescents as demonstrated for the example of conventional X-ray procedures. MATERIALS AND METHODS: A consecutive series of 166 outpatient X-rays, selected by fixed criteria, was analysed according to both diagnostic aspects and radiation protection. RESULTS: The X-rays examined were mainly gathered from orthopedic and radiological practices and from hospital radiological departments. The majority of these outpatient X-rays showed significant deficiencies regarding exposure, appropriate field size, and focussing or positioning of the patient. After the evaluation of the 166 X-rays by a total-score, 25% (42/166) of the X-rays were considered to be diagnostically insufficient. CONCLUSIONS: Improvements in outpatient radiodiagnostics are necessary to ensure adequate radiodiagnostic care of children and adolescents.

Adolescent↗
PubMed1998

[Diagnosis of vesicoureteral reflux with echo-enhanced micturition urosonography].

AIM: To ascertain the diagnostic efficacy of reflux sonography with the application of the echo-enhancing agent Levovist in comparison with X-ray voiding cystourethrography (VCUG). PATIENTS AND METHODS: Echo-enhanced voiding urosonography (VUS) and VCUG were performed successively in one examination session in 114 children referred for the investigation of possible vesicoureteral reflux (VUR). After sonography of the urinary tract the bladder was filled with normal saline and Levovist was administered. Reflux was diagnosed when hyperechogenic, floating microbubbles appeared in the ureters or renal pelvises. RESULTS: A total of 226 kidney-ureter units were available for analysis. Reflux was diagnosed in 80 units. All grades of reflux were represented. In 15 kidney-ureter units VUR was diagnosed with echo-enhanced VUS but was not seen at VCUG. The contrary was true in 3 units. High sensitivity and specificity in comparison to the VCUG could be attributed to the echo-enhanced VUS. The long imaging window attainable with Levovist makes the documentation of convincing images possible, contributing to the high diagnostic efficacy. CONCLUSION: Echo-enhanced VUS is comparable to VCUG in the diagnosis of reflux.

Adolescent↗
PubMed1998

[SieScape--a new dimension of ultrasound imaging in pediatric radiology].

The extended field of view imaging procedure named "SieScape" provides, for the first time, a mode of establishing in real time a sonographic picture up to 60 cm in length. This allows the display of large organs or tumors as well as large areas of the body in a single view, without having to assemble several pictures. Furthermore, pathological findings can be shown in full size in their surroundings. This method makes it considerably easier to convey sonographic results to the therapist who is not present at the investigation and to control a finding, for instance a tumor, during therapy.

Child↗
PubMed1998

[Morphologic image processing operators: reduction of partial volume effects for improved 3D visualization of CT data].

AIM: The quality of segmentation and three-dimensional reconstruction of anatomical structures in tomographic slices is often impaired by disturbances due to partial volume effects (PVE). The potential for artefact reduction by use of the morphological image processing operators (MO) erosion and dilation is investigated. DESIGN: The CT examinations of 31 patients with pathological alterations in lung or brain were segmented using automatic region growing and the MO were applied in a different number of iterations. The processed regions were 3D-reconstructed (shaded surface display, MIP, volume rendering) and the occurrence of PVE-related artefacts using the signal-to-background ratio (SBR) prior to and after MO application was compared. RESULTS: For all patients under review, the artefacts caused by PVE were significantly reduced by erosion (lung: mean SBRpre = 1.67, SBRpost = 4.83; brain: SBRpre = 1.06, SBRpost = 1.29) even with only a small number of iterations. Region dilation was applied to integrate further structures (e.g. at tumor borders) into a configurable neighbourhood for segmentation and quantitative analysis. CONCLUSIONS: The MO represent an efficient approach for the reduction of PVE artefacts in 3D-CT reconstructions and allow optimized visualization of individual objects.

Densitometry↗
PubMed1998

Sonomorphology and involution of the normal urachus in asymptomatic newborns.

BACKGROUND: The number of reports on the sonomorphology of the urachus or urachal remnants in neonates and the pattern of involution is limited. OBJECTIVE: To determine whether a sonographically visible urachus in the first months of life is a pathologic condition and whether postnatal involution can be demonstrated by ultrasound. MATERIALS AND METHODS: A total of 102 asymptomatic infants (premature and term newborns) were examined with a high-resolution 7.5-MHz linear transducer between 0 and 60 days of age. In 70 infants, a second examination followed 3-5 months later. RESULTS: In all infants, the urachus could be identified on the first examination. Different morphological types were differentiated. There was no difference between premature and term newborns in the morphology of the urachus. Spontaneous involution of the urachus was observed in all infants receiving a second examination, and they most often showed a fusiform urachal remnant at the apex of the bladder. CONCLUSION: Involution of the urachus is not complete at birth and can be followed up sonographically in the first months of life. This knowledge should prompt a new strategy in young infants with a discharging umbilicus or even an infected urachus. Instead of early surgery, a conservative approach under sonographic control seems reasonable, because there is a chance of spontaneous involution and any abnormal development can be detected by ultrasound.

Female↗
PubMed1998

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.

Case-Control Studies↗
PubMed1998

US, CT and MR imaging characteristics of nephroblastomatosis.

OBJECTIVES: To describe the imaging features of nephroblastomatosis with US, CT and MR, to point out characteristics of differentiation between nephrogenic rests (NR) and Wilms' tumour (WT) and to determine the most appropriate imaging modality. MATERIALS AND METHODS: We reviewed the US, CT and MR images of 29 cases of histopathologically confirmed nephroblastomatosis sent to our department for reference evaluation (German nephroblastoma study). The series included 17 kidneys with NR, 6 kidneys with WT and 32 kidneys with both NR and WT. RESULTS: NR presented as multinodular, peripheral, cortical lesions, the diffuse form of distribution being less common. Foci were homogeneous and of low echogenicity, density or signal intensity. The lesions were most clearly depicted with contrast-enhanced CT and T1-weighted (T1-W) MR images. Lesions smaller than 1 cm were rarely identified by US. The most reliable criterion to differentiate NR from WT was their homogeneity. CONCLUSIONS: Contrast-enhanced CT and T1-W MR images are of similar potential and superior to US in the diagnosis of nephroblastomatosis. Due to the significant radiation dose of serial CT, MR imaging should be the method of choice wherever it is available. The cost-effectiveness and availability of US makes it ideal for serial follow-up of known lesions.

Case-Control Studies↗
PubMed1998

Eosinophilic gastroenteritis mimicking idiopathic hypertrophic pyloric stenosis.

We report two infants with eosinophilic gastroenteritis (EG). This rare disease can mimic the clinical symptoms and US appearance of idiopathic hypertrophic pyloric stenosis (IHPS). US examination of the antropyloric region with a high-frequency linear transducer can assist in the differentiation of EG from IHPS, which is important because the therapeutic approaches are completely different. Eosinophilic gastroenteritis should be considered in the differential diagnosis of IHPS, especially when there has been an ineffective pyloromyotomy.

Adrenal Cortex Hormones↗
PubMed1998

Evaluation of segmentation algorithms for generation of patient models in radiofrequency hyperthermia.

Time-efficient and easy-to-use segmentation algorithms (contour generation) are a precondition for various applications in radiation oncology, especially for planning purposes in hyperthermia. We have developed the three following algorithms for contour generation and implemented them in an editor of the HyperPlan hyperthermia planning system. Firstly, a manual contour input with numerous correction and editing options. Secondly, a volume growing algorithm with adjustable threshold range and minimal region size. Thirdly, a watershed transformation in two and three dimensions. In addition, the region input function of the Helax commercial radiation therapy planning system was available for comparison. All four approaches were applied under routine conditions to two-dimensional computed tomographic slices of the superior thoracic aperture, mid-chest, upper abdomen, mid-abdomen, pelvis and thigh; they were also applied to a 3D CT sequence of 72 slices using the three-dimensional extension of the algorithms. Time to generate the contours and their quality with respect to a reference model were determined. Manual input for a complete patient model required approximately 5 to 6 h for 72 CT slices (4.5 min/slice). If slight irregularities at object boundaries are accepted, this time can be reduced to 3.5 min/slice using the volume growing algorithm. However, generating a tetrahedron mesh from such a contour sequence for hyperthermia planning (the basis for finite-element algorithms) requires a significant amount of postediting. With the watershed algorithm extended to three dimensions, processing time can be further reduced to 3 min/slice while achieving satisfactory contour quality. Therefore, this method is currently regarded as offering some potential for efficient automated model generation in hyperthermia. In summary, the 3D volume growing algorithm and watershed transformation are both suitable for segmentation of even low-contrast objects. However, they are not always superior to user-friendly manual programs for contour generation. When the volume growing algorithm is used, the contours have to be postprocessed with suitable filters. The watershed transformation has a large potential if appropriately developed to 3D sequences and 3D interaction features. After all, the practicality and feasibility of every segmentation method critically depend on various details of the user software as pointed out in this article.

Algorithms↗
PubMed1998

Sonographic determination of the thickness of the peritoneum in healthy children and paediatric patients on CAPD.

BACKGROUND: Prolonged peritoneal dialysis and frequent episodes of peritonitis lead to structural changes and thickening of the peritoneum. Ultrasonography investigations may provide the opportunity to detect morphological changes early, but no systematic investigations have been performed yet. METHODS: Normal values of peritoneal thickness were obtained by systematically examining 131 healthy children (0-15 years) by ultrasound. Parietal peritoneal thickness was best measured at the sternal-umbical line distal from the xiphoid. Growth charts with 95% intervals were prepared. The data of 26 patients with end-stage renal failure (5-18 years) were compared to those of the normal children. RESULTS: The variation coefficient for the consecutive measurements was only 5%, interobserver error was approximately 7%. Whereas gender did not have any influence, peritoneal thickness was significantly correlated to age, weight and most obviously to height (r = 0.81; P<0.001). Children treated only by haemodialysis had normal values, while an increased thickness, loss of movement, and adhesion of the two peritoneal layers were found in children on CAPD. These changes were only noted in patients who had a history of peritonitis. CONCLUSION: Ultrasound examination is a simple, noninvasive and precise method to measure the peritoneal changes in children on CAPD.

Adolescent↗
PubMed1998

Metacarpal index in short stature before and during growth hormone treatment.

AIMS: To assess the usefulness of the metacarpal index (MCI) as a radiographic measure of the proportions of the metacarpals in the differential diagnosis of short stature. To investigate the significance of the MCI in following the longitudinal growth and proportions of individual long bones during growth hormone stimulated catch up growth in children with short stature with and without growth hormone deficiency. SUBJECTS: 124 children, including 65 children with short stature caused by growth hormone deficiency, 13 with familial short stature, 29 with idiopathic short stature, and 17 with Ullrich-Turner syndrome. METHODS: Retrospective analysis of the MCI in five posterior-anterior radiographs of the left hand of all patients, which were performed sequentially for routine bone age determinations (Greulich and Pyle) before and during the first three years of growth hormone treatment. RESULTS: The MCI was similar in all patient groups, resembled that of healthy children, and correlated significantly with chronological age, bone age, and height before and during growth hormone treatment. Despite a remarkable growth hormone stimulated catch up growth, the MCI did not change significantly during growth hormone treatment. CONCLUSIONS: The role of the MCI is insignificant in the diagnosis of short stature, but the MCI can serve as an auxological measure of osseous proportions during longitudinal growth. Growth hormone treatment accelerates longitudinal growth without affecting the proportions of the long bones, indicating that growth hormone stimulated bone growth closely resembles spontaneous bone growth.

Body Height↗
PubMed1997

[Malignant lymphoma in childhood. Ultrasound diagnosis].

The sonographic diagnosis of malignant lymphoma in childhood is described. Malignant lymphomas are sonographically relatively uniform: initial enlargement of the lymph nodes and organs involved and disturbance of normal echo texture by mainly hypoechoic lesions can be found. Generally, four sonographic patterns of infiltration are described: diffuse, small nodular, large nodular and bulky type. Secondary, tumor-related or inflammatory complications (e.g. dislocation or compression of vessels, thoracic inlet syndrome, venous thrombosis, ileus, urinary retention, abscess and effusion) can be sonographically evaluated. Response to therapy correlates with normalization of size and echo texture and recovery from tumor-related complications. Differential diagnosis with ultrasound is based on the topographic distribution and echo pattern of infiltration and, with certain restrictions, on the echogenicity of lesions and perfusion feasible with Doppler sonography. The primary diagnosis has to be established histologically.

Child↗