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Biomedical subjects

F Rypens

Publications and source records attributed to F Rypens.

At least 19 recordsLinked to original sources
PubMed2001

Fetal lung volume: estimation at MR imaging-initial results.

PURPOSE: To plot normal fetal lung volume (FLV) obtained with fast spin-echo magnetic resonance (MR) images against gestational age; to investigate the correlation between lung growth and fetal presentation, sex, and ultrasonographic (US) biometric measurements; and to investigate its potential application in fetuses with thoracoabdominal malformations. MATERIALS AND METHODS: In a prospective multicenter study, 336 fetuses suspected of having central nervous system disorders underwent fast spin-echo T2-weighted lung MR imaging. Data obtained at 21-38 weeks gestation in 215 fetuses without thoracoabdominal malformations and with normal US biometric findings were selected for an FLV normative curve. FLV measurements obtained at pathologic examination with an immersion method were compared with MR FLV measurements in 11 fetuses. MR FLV values in 16 fetuses with thoracoabdominal malformations were compared with the normative curve. RESULTS: Normal FLV increased with gestational age as a power curve; the spread of values increased with age. Interobserver correlation was excellent (R(2) = 0.96). FLV measurements at MR imaging were 0.90 times those at pathologic examination. A constant ratio (0.78) between FLV on the left and right sides was observed. No significant difference in FLV was observed between fetal presentations. Normal FLV was observed in all fetuses with cystic adenomatoid malformations and in four of six with oligohydramnios. Lowest FLV values were observed in fetuses with diaphragmatic hernia. CONCLUSION: In fetuses with normal lungs, FLV distribution against gestational age is easily assessed in utero with fast spin-echo T2-weighted MR imaging. These preliminary findings illustrate the potential for comparing FLV measurements in fetuses at risk of lung hypoplasia with normative values.

Abnormalities, Multiple↗
PubMed2001

Prenatal diagnosis and postnatal follow-up of pericallosal lipoma: report of seven new cases.

BACKGROUND AND PURPOSE: Pericallosal lipomas are rare tumors. Few reports have included their imaging characteristics. Furthermore, little is known about their evolutive course. Our purpose was to describe the imaging features of seven cases of pericallosal lipoma diagnosed in utero and followed up after birth. METHODS: We reviewed seven cases of pericallosal lipoma diagnosed by obstetric sonography (n = 7) and examined by fetal MR imaging (n = 5). Analysis of the complementary findings provided by fetal MR imaging was conducted. All findings were correlated with the postnatal imaging and clinical findings. RESULTS: Obstetric sonography easily showed the pericallosal lipoma in all seven patients. In one, however, it was misinterpreted as intracranial hemorrhage. The morphology and integrity of the underlying corpus callosum were less easy to assess by using sonography. Fetal MR imaging confirmed the fatty content and location of the lesion in all five cases. It showed the choroidal extension in two patients and the type of associated callosal anomaly in another patient better than did sonography. In two patients, the lipoma grew, as revealed by subsequent postnatal MR imaging. The results of the neurologic examinations remained normal for the five surviving patients at a mean follow-up of 3 years (1 month-9 years). CONCLUSION: Obstetric sonography is able to easily show pericallosal lipoma. Fetal MR imaging may be useful to characterize the lipomatous nature and the extension of the lipoma and the status of the corpus callosum. Long-term follow-up is necessary to understand the clinical consequences of such lesions.

Agenesis of Corpus Callosum↗
PubMed2000

MRI spectrum of cortical malformations in tuberous sclerosis complex.

The diagnostic and prognostic value of magnetic resonance imaging in the tuberous sclerosis complex has increasingly been recognized. In this paper, we review the presumed pathogenesis of the cerebral dysgenesis seen in this condition in the light of magnetic resonance imaging features of selected patients. In addition to typical findings related to tubers, we show and discuss varied cortical malformations (from simple localized cortical dysplasia to transmantle dysplasia and schizencephaly) similar to those seen in sporadic cerebral dysgenesis. These cases support the hypothesis that the tuberous sclerosis complex focally affects the radial glial-neuronal complex as a basic unit for brain development. Abnormal stem cells would create dysplastic glia and neurons that fail to differentiate, proliferate, migrate and form a normally organized cortex.

Cell Differentiation↗
PubMed1999

Sporadic case of trichorhinophalangeal syndrome type III in a European patient.

Trichorhinophalangeal syndrome type III (TRP III) shares common traits with TRP I and II, including sparse hair, a "pear-shaped" nose, osteodysplasia with cone-shaped epiphyses, and autosomal dominant inheritance, but is distinguished by the presence of severe brachydactyly. TRP III was first described in 1984 in Japanese patients, one sporadic case [Sugio and Kajii, 1984: Am. J. Med. Genet. 19:741-753,1984] and two families [Niikawa and Kamei, 1986: Am. J. Med. Genet. 24:759-760; Nagaï et al., 1994: Am. J. Med. Genet. 49:278-280], and more recently in a Turkish family [Itin et al., 1996: Dermatology 193:349-352]. We report an additional observation in a patient of European descent, who presented with short stature, cone-shaped epiphyses, sparse hair, a pear-shaped nose, normal intelligence and severe brachydactyly. Neither parent had manifestations of TRP and there was no other reported case in the family, indicating a presumably fresh mutation. Our observation refines the clinical spectrum of TRP III in another ethnic background and may be of help in identifying the gene or genes for TRP syndromes.

Abnormalities, Multiple↗
PubMed1999

Renal sinus hyperechogenicity in acute pyelonephritis: description and pathological correlation.

This paper reports on the association between renal sinus hyperechogenicity and acute pyelonephritis. The medical records and imaging studies of 18 children displaying this pattern were retrospectively studied. Thickening of the renal pelvis and renal enlargement were the most frequent associated sonographic abnormalities. Further subtle findings can be found on sonography and colour/power Doppler. Their identification can help in the diagnostic approach to acute pyelonephritis and may obviate the need for other imaging modalities such as enhanced CT or 99mTc-DMSA scintigraphy. Renal sinus hyperechogenicity was also identified in a parallel study performed in female rabbits with experimental pyelonephritis and was shown, histologically, to be related to exudates of fibrin and polymorphonuclear leukocytes, interstitial oedema and micro-abscesses.

Acute Disease↗
PubMed1999

A pilot study for identifying at risk thyroid lesions by means of a decision tree run on clinicocytological variables.

Fine-needle aspiration biopsy (FNAB) is safe, inexpensive, minimally invasive, and highly accurate in the diagnosis of nodular diseases of the thyroid. However, FNAB does not provide a reliable benign versus malignant diagnosis for 100% of the cases analysed. It is possible to increase the accuracy of the cytological diagnosis by means of information contributed by different clinical variables. In the present study we evaluate the diagnostic value of 10 variables in addition to FNAB on a series of 218 specimens for which we obtained histological diagnoses including 37 cancers (17%). The diagnostic information contributed by these variables was analyzed by means of the Decision Tree technique, an artificial intelligence-related method which forms part of the Supervised Learning algorithms. The results show that Decision Trees enable some subpopulations of patients with uncertain FNAB results to be characterized.

Adolescent↗
PubMed1998

Fetal endocardial fibroelastosis: ultrasonographic findings in two cases.

EFE is a rare cardiac disorder with poor prognosis and uncertain cause. Primary and secondary forms have been described. Most authors consider that all EFE is secondary--a reactive process set off in the endocardium by stress on the myocardium. We report two cases representing the primary dilated form and the secondary contracted form. The dilated form was associated with intracavitary thrombus of the left ventricle. In both cases, an unusual presence of subendocardial calcifications was noted. The ultrasonographic findings are discussed.

Adult↗
PubMed1997

Anomalies of fetal development in GK rats.

Fetal development was investigated in Goto-Kakizaki (GK) rats. Between days 15 and 20 after identification of a positive sperm plug, the GK rats gained less weight than control animals. The number of conceptuses in each litter was not significantly different in control and GK rats. The incidence of abortive fetal development, however, averaged 39.7% +/- 9.1% in GK rats, compared with only 5.6% +/- 0.2% in control animals. The placental weight in living fetuses was slightly lower in GK rats than control rats. The crown-rump length was identical in the fetuses of control and diabetic mothers. The number of ossification points in the lumbosacral spine, pelvic girdle and anterior and posterior limbs was significantly lower in fetuses of GK rats than control animals. These anomalies could not be blamed on a lower plasma insulin concentration in GK than control animals, whether before or during (days 15-20) pregnancy. Moreover, in both control and GK rats, the insulinogenic index was raised during pregnancy. These findings indicate that GK rats represent a new model for the study of diabetes-related fetal anomalies, their pathogenesis and prevention.

Animals↗
PubMed1997

Can careful ultrasound examination of the urinary tract exclude vesicoureteric reflux in the neonate?

The aim of the study was to determine whether a urinary tract appearing normal when assessed by meticulous ultrasound (US) examination may coexist with vesicoureteric reflux (VUR) and whether a normal US scan can be used to exclude VUR, thereby avoiding unnecessary voiding cystourethrography (VCUG). The US features of 35 neonates with known VUR were reviewed. Criteria studied included pelvic dilatation above 7 mm on a transverse scan, calyceal or ureteral dilatation, pelvic or ureteral wall thickening, absence of the corticomedullary differentiation (CMD) and signs of renal dysplasia (small kidney, thinned or hyperechoic cortex and cortical cysts); all signs that have been shown to result from or to be associated with VUR. 57 refluxing renal units (RRU) were found among the 35 patients. VUR was bilateral in 22. Among the 57 RRU, at least one US anomaly that would have prompted VCUG was present in 50 (87.7%). Pelvic dilatation above 7 mm was present in 29 RRU (50.9%) only. Calyceal dilatation was present in 24 RRU, the dilatation involving the calyces but not the renal pelvis in seven. Ureteral dilatation was observed in 15 RRU. Pelvic or ureteral wall thickening was present in seven RRU. CMD was absent in 32 RRU (56.1%). US signs of dysplasia were found in 19 RRU. No US anomaly was found in seven RRU (12.3%) in six patients. A careful and meticulous US examination of the neonatal urinary tract allows the detection of over 87% of RRU by showing at least one sonographic abnormality. It is concluded that a normal appearing urinary tract on US does not usually coexist with VUR and that in such cases VCUG is not necessary.

Dilatation, Pathologic↗
PubMed1996

Sonographic prediction of chronic lung disease in the premature undergoing mechanical ventilation.

The aims of the study are to investigate the possible role of ultrasound (US) of the chest in predicting the development of chronic lung disease (CLD) in patients with hyaline membrane disease (HMD) and to determine the optimal age for the sonographic examination. One hundred and five consecutive prematures undergoing mechanical ventilation were prospectively studied by US of the chest. The US examinations were performed at birth and at least once a week until discharge from the neonatal unit. The sonographic patterns observed behind the diaphragm and their evolutions were recorded and correlated with the clinical and radiological data at day 28, which corresponds to the currently accepted limit for determining the presence of CLD. CLD is currently defined as oxygen dependency on day 28 with radiographic abnormalities. A diffuse retrodiaphragmatic hyperechogenicity was observed in all the patients with HMD. The hyperechogenicity resolved completely in patients with an uncomplicated clinical evolution. In contrast, in patients with CLD the hyperechogenicity resolved only partially, resulting in less diffuse and less extensive hyperechogenicity. Day 18 was the earliest day where the persistence of the abnormal retrodiaphragmatic hyperechogenicity was observed in 100% of the patients presenting CLD at day 28. At that time, 95.2% of the patients without abnormal hyperechogenicity showed uncomplicated evolution and no CLD. US can be a useful diagnostic tool to determine the occurrence of CLD and to predict as early as day 18 the prematures at risk for the disease.

Bronchopulmonary Dysplasia↗
PubMed1996

Antenatal diagnosis of short-limb dwarfism: sonographic approach.

Based on the findings in 12 patients with skeletal dysplasia diagnosed antenatally, the authors propose a tailored approach to the evaluation of foetuses with shortened long bones, depending on the time of discovery, the degree of shortening and the associated findings. During the second trimester, a very short femur [2 standard deviations (SD) - 5 mm and less] most probably corresponds to a bone dysplasia, although the differential diagnosis is mainly early intra-uterine growth retardation, and the foetal skeleton should be surveyed completely in order to find supplementary features suggestive of dwarfism. Anomalies of long bones in their shape, thickness or contour, or spinal ossification disorders or undermineralisation (best evaluated at the level of calvarial bones) are most helpful in determining the type of dysplasia. A short femur (between 2 SD and 2 SD - 4 mm) may indicate growth retardation, a chromosomal anomaly or dwarfism. Follow-up examinations are mandatory in order to differentiate between them. During the third trimester a very short femur may indicate a bone dysplasia and the work-up should be the same as in the second trimester. A short femur may correspond to dwarfism of late development, a growth-retarded foetus or constitutional shortness. Various ratios, especially that of the femur/foot, are helpful in differentiating between them. In case of previous family history, a short or very short femur usually indicates recurrence of the dwarfism. In all cases of antenatal diagnosis, confirmation of the sonographic findings should be obtained either by foetal or neonatal radiographs. The approach proposed by the authors should provide sufficient information to counsel the family not only for the ongoing pregnancy but also for subsequent ones.

Bone and Bones↗
PubMed1996

Desmoplastic supratentorial neuroepithelial tumours of childhood: imaging in 5 patients.

Desmoplastic neuroepithelial tumours are rare supratentorial neoplasms of infancy with a favourable prognosis. We characterised their imaging findings by reviewing the clinical and radiological reports of five affected children. The tumours were massive, predominantly cystic and with preferential frontal and parietal lobe involvement. The cystic component was in the white matter, with no communication with the ventricle. The solid part was superficially, abutting a meningeal surface, and showed intense contrast enhancement. A heterogeneous predominantly solid mass was observed in one patient. Thinning and deformation of the skull adjacent to the tumour was shown in four cases. Peritumoral oedema was absent or moderate. No calcification or haemorrhage were present. Angiography showed a tumour blush from the internal or external carotid arteries in one case each. Follow-up (3 months-9 years, mean 4.5 years) showed no recurrence.

Angiography↗
PubMed1996

[Abdominal complications of ventriculoperitoneal shunts].

Three cases of abdominal complications of ventriculo-peritoneal shunts are reported. Abdominal pseudocysts were identified in 2 patients (surinfection was proven in one of them). Malposition of the shunt was demonstrated for the third patient. Ultrasound was the most helpful imaging technique for the detection of these abdominal complications. Abdominal computed tomography confirmed the sonographic findings before the patients were reoperated.

Abdomen↗
PubMed1995

Twin-twin transfusion syndrome--possible roles for Doppler ultrasound and amniocentesis.

A 29-year-old woman was referred for suspicion of twin-twin transfusion syndrome (TTTS). Several ultrasonographic and neonatal criteria of TTTS were encountered in this twin pregnancy. The peculiar observations in this case were, firstly, the demonstration of superficial anastomosis by Doppler ultrasound and, secondly, that one single therapeutic amniocentesis could have been sufficient to partially correct the progression of the syndrome, as after amniocentesis it was no longer possible to demonstrate the vascular communication. This observation suggests that superficial anastomoses could also have a role in the genesis of TTTS. Their effect could be monitored by Doppler ultrasound and could be more easily corrected by therapeutic amniocentesis.

Adult↗
PubMed1995

Atypical and equivocal sonographic features of the spinal cord in neonates.

Thanks to the wider use of sonography to examine the spinal content in the neonate, normal anatomy and anomalies may be detected easily. Yet, unusual sonographic patterns are also observed. These must be differentiated from true pathologies. During a prospective study of 103 neurologically asymptomatic neonates, atypical sonographic patterns were found in 16 patients, corresponding to normal variants in 13. Nine of these 13 patients presented with a widening of the distal part of the central echo complex (one had a dilated ventriculus terminalis). Nerve roots of the cauda equina were disposed asymmetrically in three patients; the spinal cord movements were still present. In two of these babies, this distribution was associated with thin arachnoid pseudocysts. One patient presented with transitorily hyperechoic and narrow subdural spaces, probably related to neonatal dehydration. None of the 13 patients showing normal variants required any treatment. The other 3 patients (of 16) presented with equivocal entities of unknown evolution: sonographic tethered cord, fibrolipoma of the filum terminale and epidural varices. Sonography is highly accurate in evaluating the spinal cord content and aids differentiation of normal and normal variants from equivocal or pathological entities.

Diagnosis, Differential↗