The contribution of fetal MR imaging to the assessment of oesophageal atresia.

OBJECTIVE: Present challenges are to improve the diagnosis rate of oesophageal atresia (OA) and evaluate as completely as possible a fetus affected by OA, specifically the type of OA and the length of the gap. Our aim was to evaluate the accuracy of fetal MR imaging (fMRI) for diagnosis of OA. METHODS: We reviewed fMRI performed because of sonographic suspicion of an OA. The signs reviewed included stomach size, "pouch sign", bowing of the trachea and visualization of the lower oesophageal lumen. The fetuses were assigned by consensus as having or not having EA, as well as having a tracheaoesophageal fistula (TOF). All findings were correlated with postnatal data. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were calculated. RESULTS: Se, Sp, PPV and NPV of the technique were respectively 91%, 100%, 100% and 88%. The presence of the pouch sign yielded corresponding values of 82%, 100%, 100% and 78%. Mid-tracheal bowing was correlated positively with EA. The type of atresia was correctly evaluated in 90% of patients. CONCLUSION: fMRI is useful for the diagnosis of EA through the visualization of the oesophageal pouch or through associated signs such as tracheal bowing. Visualization of the lower oesophageal lumen seems to be a good sign of TEF. KEY POINTS: • Challenges are to improve the prenatal diagnosis of EA and associated malformations. • fMRI is able to diagnose EA through demonstration of the pouch sign. • Tracheal bowing is a promising indirect sign of EA. • Tracheoesophageal fistula can also be suspected thanks to fMRI. • Obstetrical US, fMRI and fetal CT are complementary for assessing associated malformations.

The case of HNF-1beta mutation with medullary cysts.

We describe one case of long-term post-natal follow-up of hyperechoic fetal kidneys related to HNF-1beta mutation with cystic changes over a 9-year period in a female patient. This diagnosis was suspected on the basis of the renal US findings and was confirmed by complementary genetic examination. After birth, cortical cysts were detected and at the age of 4, medullary cysts were found, that disappeared with time. Currently our patient displays hyperechoic kidneys with only cortical cysts. This case report highlights the variability of US appearances in relation with HNF-1beta genetic mutation.

ESPR uroradiology task force and ESUR paediatric working group: imaging recommendations in paediatric uroradiology, part IV: Minutes of the ESPR uroradiology task force mini-symposium on imaging in childhood renal hypertension and imaging of renal trauma in children.

Two new recommendations of the European Society of Radiology task force and the European Society of Uroradiology workgroup on paediatric uroradiology are presented. One deals with diagnostic imaging in children after trauma to the urinary tract-renal trauma, in particular. The other concerns the evaluation of suspected renal hypertension. Available data in the paediatric literature are either unsatisfactory or controversial for both of these clinical settings. Therefore, the following consensus-based proposals aim at outlining effective imaging algorithms to reduce invasive imaging procedures while optimising diagnostic accuracy. The objective of following a more uniform imaging approach is to facilitate future meta-analysis as well as multicentre and other more evidence-based studies. The practise in paediatric radiology is typically based on local availability and on the limitations of professional expertise and equipment, balanced against the perceived needs of the individual child. Although this is unlikely to change in the near future, it does not release the physicians in charge of diagnostic imaging from their responsibility in choosing and providing state-of-the-art imaging and management protocols that are adapted specifically for use in children.

[Imaging of urinary tract infection in children]. / Imagerie de l'infection urinaire de l'enfant.

Urinary tract infection is very common in children. Its diagnosis, management and treatment have led to abundant literature and many controversies. The main challenges are to identify patients at risk of infection and those at risk of complicated infections. Long-term complications include reflux nephropathy, renal hypertension and stage renal disease. Imaging has a triple role: to confirm the diagnosis in patients with equivocal clinical symptoms; to determine patients at risk of recurrence; prevention of infection by detecting already in utero patients with congenital malformation. During the acute phase, Ultrasound has an important role in detecting favouring conditions such as urinary tract dilatation. The use of color Doppler increases the sensibility and specificity of ultrasound. To date, DMSA scan is the key examination for demonstrating the parenchymal lesions. CT-scan and MRI are rarely used in this acute phase. Retrograde voiding cystography (RVC) will be used whenever vesico-ureteric reflux is suspected. A decision algorithm can be proposed bases on US and DMSA; RVC will be performed whenever one of them is positive. CT or MRI will be used to look for abscesses complicating the UTI. DMSA scan is the gold standard for detecting renal scanning, sequellae of the infection. In the future, the role of MRI will surely increase for the demonstration of uropathy acute and sequelae of the renal involvement.

Evolution of fetal ultrasonography.

The authors wish to highlight the evolution that has occurred in fetal ultrasound in recent years. A first significant evolution lies in the increasing contribution of first trimester ultrasound for the detection of fetal anomalies. Malformations of several organs and systems have been diagnosed during the first trimester. Furthermore the systematic measurement of the fetal neck translucency has led to increasing rate of detection of aneuploidies and heart malformations. For several years now, three-dimensional (3D) and 4D ultrasound (US) have been used as a complementary tool to 2D US for the evaluation of fetal morphology. This brings an improved morphologic assessment of the fetus. Applications of the techniques are increasing, especially for the fetal face, heart and extremities. The third field where fetal US is continuously providing important information is the knowledge of the natural history of diseases. This has brought significant improvement in the postnatal management of several diseases, especially urinary tract dilatation and broncho-pulmonary malformation.

[Management of isolated fetal dilatations of the kidney pelvis]. / Prise en charge des dilatations pyéliques foetales isolées.

The most common sonographic abnormality found in the fetal urinary tract is collecting system dilatation, accounting for 4.5% of examinations. Numerous renal pelvis measurements and various gestational age cut-off points have been recommended in the assessment of obstructive fetal uropathy. As a result, renal pelvic measurements are not well standardized. The first measurements of the renal pelvis diameter in the 80's suggested that a threshold value of 10 mm was significant in order to distinguish between physiologic and pathologic dilatations. The routine use of prenatal ultrasound and the improving resolution of ultrasound equipment allow the detection of smaller dilatations. The third-trimester threshold value for the antero-posterior renal pelvis diameter of 7 mm is the best ultrasound criterion to predict postnatal renal abnormalities with a positive predictive value of 69%. A renal pelvis dilatation during the second trimester of pregnancy can be used as a warning sign for urinary tract malformation, and should not be ignored even if there is no further progression in the third trimester, because this finding may reveal a significant urologic abnormality in 12% of cases. Isolated pyelectasis can signal the presence of vesico-ureteral reflux. Normal appearing urinary tract on 2 successive neonatal ultrasound rarely coexist with significant abnormal findings on voiding cysto-urethrography. Therefore, in such cases, invasive investigations are not justified.

The role of MR imaging for the assessment of complicated duplex kidneys in children: preliminary report.

OBJECTIVE: To determine whether MR imaging, including MR urography, is able to assess complicated duplex kidneys and to determine the possible role of MRI compared to other imaging techniques in such uropathies. MATERIAL AND METHODS: Twenty consecutive patients (age 1 month-11 years) presenting with a suspicion of a complicated duplex kidney were prospectively studied with MRI and MR urography. The examinations were performed on a 0.5-T machine using routinely available sequences that were optimised to the patient's age and size. MR images were reviewed separately by two observers blinded to the patient history. They were asked to assess the presence of a duplex kidney, the presence of an abnormality that may require surgery and to indicate the type of the inferior ureteric insertion. A qualitative gradation of these results was performed on the basis of the final diagnosis provided at endoscopy (n = 6) or surgery (n = 14). MR results were compared to those provided by US examinations and excretory urography, when available, and a non-parametric statistical analysis was performed. RESULTS: MRI differentiated well between the upper and the lower poles of the kidneys and correctly answered the three questions in all 20 patients. The two observers agreed completely in all the 20 patients. MR was statistically superior to both US and excretory urography in the evaluation of the distal ureter (P < 0.05). CONCLUSIONS: MRI provides a precise assessment of the complications associated with duplex kidneys. Its optimal role seems to be the assessment of ectopic extra-vesical ureteric insertions and whenever an occult upper pole is suspected.

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.

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.

Vesicoureteral reflux in children: endoscopic treatment.

Endoscopic correction of vesicoureteral reflux in children has been increasingly used in the last years with encouraging results. During a 4-year period 152 children were treated by endoscopic injection of Teflon. A follow-up, ranging from 3 months to 5 years, was available for 173 refluxing ureters. For primary reflux, correction was observed after a single injection in 87% of the cases and in 93% after a second injection in some failures. In duplication, the technique is somewhat more difficult but the results quite satisfactory with 58% success after one injection, increasing to 74% after a second injection. The limitations of these techniques are underlined, the major concern being the safety of the injectable Teflon particles, eliciting a foreign-body granulomatous reaction with the potential hazard of distant migration. So far no long-term morbidity and complications have been observed with the use of Teflon to correct reflux. Extensive pathological study in 7 children submitted to ureteral reimplantation for failure of endoscopic correction showed a typical encapsulated granulomatous reaction below the intramural ureter, but particles of Teflon were noted in only one hypogastric ganglion when the Teflon was injected outside of the bladder. There is a need for finding an ideal substance for endoscopic injection, preferably prepared from the patient's own tissue allowing simple and safe correction of vesicoureteral reflux in children.

[Morphologic study of ultrasonic placental anomalies in the second half of pregnancy]. / Etude morphologique des anomalies placentaires échographiques de la deuxième moitié de la gestation.

Fifty cases of placental lesions detected by sonography during the second half of pregnancy were pathologically investigated. Sonographic evaluation included the size of the lesion, its echogenicity on subsequent examinations and location in relation to the placental margin and umbilical cord insertions. Classical pathologic examination was performed after delivery to confirm the ultrasonographic findings. The echogenic pattern of these lesions was distinct from that of the rest of the placenta and the lesions were classified in two categories. The parenchymal lesions including 19 intervillous thrombosis, 14 caverns, 3 cases of hydatidiform changes, 2 infarcts, 1 septal cyst and one case of fibrin deposition and, the chorionic lesions including 5 subchorionic thrombosis, 3 cases of extrachorial placentas and 2 amniotic cysts. Therefore diagnostic ultrasound gives the clinician a unique opportunity to perform detailed examination of the placenta in vivo and can be an effective and non-invasive way to diagnose different types of lesions that are usually described in the post-partum by the pathologist.

[Perinatal research on feto-maternal anti-Kell immunization]. / Investigations périnatales de l'immunisation foeto-maternelle anti-kell.

Three cases of pregnancies complicated by feto-maternal anti-Kell iso-immunisation are presented, as well as a review of the literature. The evolution of new techniques for antenatal diagnosis has made it possible to have a new approach to this fetal pathology. Chorionic villus biopsy can be carried out in the first trimester of pregnancy when there has previously been a serious incidence of anti-Kell immunisation with a couple where the husband is heterozygous for the Kell antigen. In the second and third trimesters the surveillance of the patient is essentially dependent on ultrasound examination of the fetus and placenta, which makes it possible to detect hydropic changes, and also depends on blood sampling from the cord which makes it possible to assess by direct measurement the degree of fetal anaemia. Now pulsed Doppler must be added to these classical diagnostic techniques because it allows a gross estimation of fetal haematocrit levels.

Umbilical cord pseudocyst in trisomy 18.

Prenatal diagnosis of cord defects by means of ultrasound examination is possible and highly accurate. Although this is a rare pathological finding, we report two cases in which umbilical cord pseudocysts were associated with trisomy 18. These observations underscore the need of umbilical blood sampling for establishing the karyotype in fetuses with such umbilical cord anomalies and the importance of careful examination of placentas and infants born with such defects.