What is the value of magnetic resonance venography in children before renal transplantation?

Radiological evaluation before renal transplantation includes imaging of vascular anatomy, as thrombosis, narrowing and anomalies of the inferior vena cava (IVC) and/or iliac veins (IV) can influence the surgical technique. Most cases only require investigation with Doppler vessel ultrasonography (US), with magnetic resonance venography (MRV) reserved to clarify US findings and investigate high-risk patients. The purpose of this study was to compare these modalities in evaluating IVC and IV and correlate imaging and operative findings of patients at RTx surgery. Twenty-nine children, 21 (72%) of whom had subsequent RTx surgery, were investigated over 5 years with correlation of US and MRV in 62% (18 of 29). Technically difficult US examinations needing MRV for clarification occurred in six (21%), and normal US with anatomical variations on MRV was seen in three (10%). The anatomical variations consisted of left-sided IVC, aberrant right common femoral vein and a left IV partly draining into the azygos and renal veins. US is an excellent screening tool for evaluating vascular anatomy patency in children. MRV infrequently contributes beneficial information, is difficult to justify as a screening tool, and due to the risks of gadolinium in uraemia, should only be used on an individual patient basis.

Postnatal investigation of fetal renal disease.

Following the introduction of routine prenatal scanning, and more recently detailed anomaly scans, antenatal ultrasound (US) diagnosis of fetal renal tract abnormalities has become well established. Prenatal detection has resulted in a group of asymptomatic infants becoming patients in the last two decades. These infants are referred for paediatric (general, urological and nephrological) consultations, radiological imaging and monitoring. The urgency with which to undertake imaging depends on the suspected antenatal diagnosis and clinical scenario, with bilateral hydronephrosis, posterior urethral valves and complicated duplex systems taking a high priority. Treatment is mainly preventive and relies on close follow-up and timely intervention. US remains the main imaging modality of choice postnatally; together with nuclear medicine, it gives a powerful combination of both anatomy and function. However, magnetic resonance urography may have increasing importance in becoming the investigation of choice of the future for more complex cases.

Mutation analyses of Uroplakin II in children with renal tract malformations.

BACKGROUND: Uroplakin (UP) proteins cover urothelial apical surfaces. Mice lacking UPIIIa have elevated urothelial permeability and congenital renal tract anomalies, and UPIIIa mutations have been reported in children with kidney and ureter malformations. Mice with null mutation of another UP family member, UPII, are often born with congenital hydronephrosis. We hypothesized that UPII mutations may be present in humans with renal tract malformations. METHODS: Mutations were sought, using direct sequencing of the five UPII exons, in 42 children with diverse renal tract anomalies. RESULTS: No UPII abnormalities were detected in 41 patients, whereas one index case had a heterozygous frameshift change which, if expressed, would generate a truncated protein. This Caucasian child presented with vesicoureteric reflux (VUR), bilateral nephropathy and renal failure. The genetic change was also found in the index case's mother who had normal renal ultrasonography, but it was absent in 150 healthy Caucasian control individuals (96 assessed by direct sequencing and another 54 assessed by restriction digests). UPII was immunolocalized in urothelium of the normal human embryonic renal pelvis in a pattern similar to UPIIIa. CONCLUSION: This study offers no definitive support for UPII mutations causing human renal tract malformations. In rare patients, UPII variants might be implicated in pathogenesis when acting in conjunction with other yet-to-be-defined, genetic or environmental modifying factors.

Three-dimensional sonographic evaluation of the infant spine: preliminary findings.

PURPOSE: The aims of this study were to evaluate normal spinal anatomy in neonates and infants as seen by 3-dimensional sonography (3D US), to determine the value of 3D US in the evaluation of occult spinal dysraphia in infants, and to correlate the findings of 3D US with those of 2-dimensional sonography (2D US) and MRI, when available. METHODS: We used 2D US and 3D US to examine the lumbosacral spine in infants with cutaneous stigmata, syndromes associated with spinal dysraphia, and abnormal radiographs. We also evaluated, as controls, healthy infants who had no markers of spinal abnormality. 2D sonograms, 3D sonograms, radiographs, and MRI scans, when available, were compared to assess differences in the display of the infant spine. RESULTS: In total, we examined 29 infants: 18 subjects and 11 control infants. The correlation between 2D US and 3D US was 100% in the detection of congenital defects of the spinal cord, although 3D US allowed superior visualization of the vertebral bodies and posterior spinal elements. When a gross abnormality of the posterior spinal elements occurred with pathologic overlying soft tissue, interpretation was simpler with MRI than with sonography. CONCLUSIONS: 3D US is a useful adjunct to 2D US when screening the infant spine for congenital defects, particularly in showing alignment of posterior spinal elements and integrity of vertebral bodies. This ability is important because posterior spinal defects may be associated with underlying spinal cord abnormalities.