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Dive into the research topics where Ulrich V. Willi is active.

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Featured researches published by Ulrich V. Willi.


Pediatric Radiology | 1998

Fibrous tumours in children: imaging features of a heterogeneous group of disorders

Georg Eich; Jean-Claude Hoeffel; Heinz Tschäppeler; Ingmar Gassner; Ulrich V. Willi

Background. Fibrous tumours are predominantly soft tissue lesions which are relatively frequent in childhood but are little known. Imaging is often used in the evaluation of these tumours but their characteristics, particularly on US or MRI, have not been studied systematically. Objectives. To provide an overview of the clinical and imaging features of the different disorders, and to correlate them with the currently used classification schemes. Material and methods. Twenty-five patients with fibrous tumours were evaluated retrospectively. Clinical histories were studied for the histopathological diagnosis, age, signs and symptoms at presentation, mode of therapy and follow-up where available. Imaging findings were analysed for the following variables: number, location, size, margin and architecture of soft tissue and/or visceral lesions and the presence and pattern of osseous involvement. Comparison with the available literature was performed. Results. The following tumour types were encountered: desmoid fibromatosis (n = 9), myofibromatosis (n = 7), fibromatosis colli (n = 2), congenital-infantile fibrosarcoma (n = 2), adult-type fibrosarcoma (n = 2), fibrous hamartoma of infancy (n = 1), angiofibroma (n = 1) and hyaline fibromatosis (n = 1). Conclusions. While some tumours were non-specific in their clinical and radiological manifestation, others such as myofibromatosis, fibromatosis colli, fibrous hamartoma of infancy and angiofibroma exhibited a characteristic pattern which allowed a diagnosis to be made even without histology.


Pediatric Radiology | 1994

Juvenile chronic arthritis: imaging of the knees and hips before and after intraarticular steroid injection.

Georg Eich; F. Hallé; J. Hodler; Reinhard Seger; Ulrich V. Willi

Intraarticular steroid therapy in juvenile chronic arthritis (JCA) is performed because of high local efficacy with few side effects. Imaging is used for initial evaluation and for monitoring of treatment response. The aim of this study was to compare imaging findings in diseased hips and knees before and after therapy. A prospective study was performed on 10 patients (15 joints) scheduled for intraarticular therapy. Pretherapeutic assessment included clinical work-up, radiographs, ultrasound (US), and magnetic resonance imaging (MRI) of affected joints. Following therapy, clinical and sonographic examinations were performed at 1 week and 1 month. MRI was repeated at 1 month. MRI and US demonstrated pannus formation and effusion, but differentiation was less distinct on US. Popliteal cysts and lymph nodes were visible in both modalities. MRI additionally revealed articular cartilage loss and subchondral cysts, not shown by US. Epiphyseal overgrowth and osteopenia were best seen radiographically. At present MRI is the best tool to assess the inflammatory changes of the joints in JCA. Initial staging of the joints may be done with plain films and MRI. US is useful to assess effusion and pannus and may be used to monitor treatment response.


Pediatric Radiology | 1991

Testicular adrenal-like tissue (TALT) in congenital adrenal hyperplasia: detection by ultrasonography.

Ulrich V. Willi; M. Atares; A. Prader; M. Zachmann

In a consecutive series of 15 male adolescents and young adults with congenital adrenal hyperplasia (CAH), the size, shape, firmness and echostructure of the testes were assessed. The latter was abnormal in 7 patients under long standing treatment with glucocorticoids (group I). In 8, 5 under and 3 off treatment for several years, ultrasonography (US) was normal (group II). On the basis of the US findings the patients were placed in two groups. In group I, the testes had a heterogeneous ultrasonographic pattern; clinically, most felt hard and irregular, although their volume was normal. Sperm count in 3 patients was 5.0 to 14.4×106/ml. Five patients have 21-hydroxylase deficiency that was diagnosed in early infancy and had salt-wasting; two have 11-beta-hydroxylase deficiency that was diagnosed late and had no salt-wasting. In group II, testicular volume, shape, firmness and echostructure were normal. All have 21-hydroxylase deficiency, no history of salt-wasting and were diagnosed late. Sperm counts in 3 patients off treatment were 10.5 to 66.0×106/ml. In severe cases with a history of salt loss, TALT with deficient spermiogenesis seems likely despite treatment. In mild cases, TALT is absent and spermiogenesis may be normal even without treatment. US is much more accurate in assessing the testes than palpation.


European Radiology | 2001

Cerebral venous thrombosis in childhood

Thierry A.G.M. Huisman; David Holzmann; Ernst Martin; Ulrich V. Willi

Abstract. This was a retrospective study to determine different etiologies of cerebral venous thrombosis (CVT) in childhood and to correlate extent and location of thrombosis with the etiology and the age of the child as well as the final outcome. In addition, the radiologic approach is discussed. This was a retrospective analysis of 19 children with CVT. The children were examined by contrast-enhanced dynamic CT. Radiologic findings were correlated with the etiology of CVT. Cerebral venous thrombosis is not as infrequent in children as has been thought. Cerebral venous thrombosis in children can occur due to trauma (n=9), infections (n=7), or coagulation disorders (n=3). Extent and location of thrombosis, as well as complications, final outcome, and therapy, depend on the etiology. Computed tomography remains a valuable primary imaging modality in the diagnosis of CVT in the acutely injured or diseased child.


European Journal of Pediatrics | 1992

Connatal rickets following repeated administration of phosphate enemas in pregnancy: A case report

Peter C. Rimensberger; G. Schubiger; Ulrich V. Willi

We present a case of antenatal failure of bone growth and mineralisation in a newborn whose anorectic mother repeatedly administered hypertonic phosphate enemas during pregnancy. Phosphate overload in pregnant women appears to impede calcification of the fetal skeleton.


Pediatric Radiology | 2003

Burkitt's lymphoma with bilateral cavernous sinus and mediastinal involvement in a child

Thierry A.G.M. Huisman; Frank Tschirch; Jacques Schneider; Felix Niggli; Ernst Martin-Fiori; Ulrich V. Willi

We report a 12-year-old boy who presented with incomplete right ophthalmoplegia, exophthalmos and headache. Initial CT and MRI revealed a mass in the right cavernous sinus. During tumour work-up, CT identified additional tumour within the mediastinum. Biopsy of the mediastinal lesion identified Burkitts lymphoma. We report on this case because radiologists and clinicians should be alerted to identify sites of primary Burkitts lymphoma outside of the central nervous system if clinical symptoms indicate, or imaging shows, CNS lesions. Primary CNS involvement in Burkitts lymphoma is rare.


Pediatric Surgery International | 1998

Cystic nephroma : a rare benign renal tumor

P. Sacher; Ulrich V. Willi; Felix Niggli; Thomas Stallmach

Abstract We report two boys aged 1 year and 2 years 2 months, respectively, with cystic nephromas. Both presented with a painless abdominal mass. Computed tomography showed a homogeneous, multicystic tumor of the lower pole of the kidney in both cases with thin septa without solid parts. Macroscopically, the surface of the tumor was smooth. Both patients underwent a renal-sparing procedure; histology confirmed the diagnosis of cystic nephroma.


Pediatric Radiology | 2006

Pre- and postnatal imaging of a girl with a cloacal variant.

Thierry A.G.M. Huisman; Marianne van der Hoef; Ulrich V. Willi; Rita Gobet; Robert L. Lebowitz

We describe the prenatal MR findings in a 29-week fetus with a cloacal variant (urogenital sinus and anterior placed anus) in combination with an enlarged clitoris and urethral duplication and correlate them with postnatal imaging. Fetal MR imaging permits the diagnosis and characterization of cloacal and urogenital sinus malformations in utero. This information may guide pre-, peri- and postnatal management.


American Journal of Rhinology | 2001

Allergic rhinitis as a risk factor for orbital complication of acute rhinosinusitis in children

David Holzmann; Ulrich V. Willi; David Nadal

The purpose of this article is to determine allergic rhinitis and age as potential risk factors for the development of orbital complications of acute rhinosinusitis in children. One hundred two children presenting with orbital swelling were investigated by computed tomography (CT) of the paranasal sinuses and the orbit as well as for underlying allergic rhinitis. Sixty (58.8%) patients had orbital complications of clinical and radiological acute rhinosinusitis. They were grouped accordingly: preseptal cellulitis (n = 24), periostitis (n = 10), and subperiosteal abscess (n = 26). No abscess within the orbit or cavernous sinus thrombosis was found. Thirty-four (56.7%) of the 60 patients underwent allergy investigation. Allergic rhinitis was found in 9 (64.3%) of 14 children with preseptal cellulitis, in 1 (25%) out of 4 children with periostitis, and in 13 (76.5%) out of 17 children with subperiosteal abscess. The prevalence of allergic rhinitis was significantly higher in patients presenting in pollen season from February to August (17:4) than in patients presenting in the period between September and January (6:7). Thus, allergic rhinitis may be a cofactor in the pathogenesis of orbital complications of acute rhinosinusitis. According to our study population, age only influences the type of orbital complication of acute rhinosinusitis in the sense that older children are more likely to develop subperiosteal abscess, whereas younger children develop preseptal cellulitis.


Pediatric Radiology | 2004

Solitary infantile choriocarcinoma of the liver: MRI findings

Marianne van der Hoef; Felix Niggli; Ulrich V. Willi; Thierry A.G.M. Huisman

Infantile hepatic choriocarcinoma is a rare, highly malignant germ-cell tumour believed to result from a choriocarcinoma of the placenta that spreads to the child. Most infants present with a characteristic clinical picture of anaemia, hepatomegaly and precocious puberty. Imaging findings, including conventional MRI, may be non-specific. To improve the accuracy of diagnosis, we present the imaging findings of contrast-enhanced dynamic MRI in a 4.5-month-old boy with infantile hepatic choriocarcinoma.

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David Nadal

Boston Children's Hospital

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Ernst Martin

Boston Children's Hospital

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Felix Niggli

Boston Children's Hospital

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Georg Eich

Boston Children's Hospital

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Rita Gobet

Boston Children's Hospital

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Eugen Boltshauser

Boston Children's Hospital

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