Cystic kidney diseases in children

Cystic kidney disease comprises a broad group of heterogeneous diseases, which differ greatly in age at onset, disease manifestation, systemic involvement, disease progression, and long-term prognosis. As our understanding of these diseases continues to evolve and new treatment strategies continue to emerge, correctly differentiating and diagnosing these diseases becomes increasingly important. In this review, we aim to highlight the key features of the most relevant cystic kidney diseases, underscore important diagnostic characteristics of each disease, and present specific management options if applicable.

Visual grading analysis of digital neonatal chest phantom X-ray images: Impact of detector type, dose and image processing on image quality

OBJECTIVES

To evaluate the impact of digital detector, dose level and post-processing on neonatal chest phantom X-ray image quality (IQ).

METHODS

A neonatal phantom was imaged using four different detectors: a CR powder phosphor (PIP), a CR needle phosphor (NIP) and two wireless CsI DR detectors (DXD and DRX). Five different dose levels were studied for each detector and two post-processing algorithms evaluated for each vendor. Three paediatric radiologists scored the images using European quality criteria plus additional questions on vascular lines, noise and disease simulation. Visual grading characteristics and ordinal regression statistics were used to evaluate the effect of detector type, post-processing and dose on VGA score (VGAS).

RESULTS

No significant differences were found between the NIP, DXD and CRX detectors (p>0.05) whereas the PIP detector had significantly lower VGAS (p< 0.0001). Processing did not influence VGAS (p=0.819). Increasing dose resulted in significantly higher VGAS (p<0.0001). Visual grading analysis (VGA) identified a detector air kerma/image (DAK/image) of ~2.4 μGy as an ideal working point for NIP, DXD and DRX detectors.

CONCLUSIONS

VGAS tracked IQ differences between detectors and dose levels but not image post-processing changes. VGA showed a DAK/image value above which perceived IQ did not improve, potentially useful for commissioning.

KEY POINTS

• A VGA study detects IQ differences between detectors and dose levels. • The NIP detector matched the VGAS of the CsI DR detectors. • VGA data are useful in setting initial detector air kerma level. • Differences in NNPS were consistent with changes in VGAS.

γ-H2AX foci as in vivo effect biomarker in children emphasize the importance to minimize x-ray doses in paediatric CT imaging

Objectives

Investigation of DNA damage induced by CT x-rays in paediatric patients versus patient dose in a multicentre setting.

Methods

From 51 paediatric patients (median age, 3.8 years) who underwent an abdomen or chest CT examination in one of the five participating radiology departments, blood samples were taken before and shortly after the examination. DNA damage was estimated by scoring γ-H2AX foci in peripheral blood T lymphocytes. Patient-specific organ and tissue doses were calculated with a validated Monte Carlo program. Individual lifetime attributable risks (LAR) for cancer incidence and mortality were estimated according to the BEIR VII risk models.

Results

Despite the low CT doses, a median increase of 0.13 γ-H2AX foci/cell was observed. Plotting the induced γ-H2AX foci versus blood dose indicated a low-dose hypersensitivity, supported also by an in vitro dose–response study. Differences in dose levels between radiology centres were reflected in differences in DNA damage. LAR of cancer mortality for the paediatric chest CT and abdomen CT cohort was 0.08 and 0.13 ‰ respectively.

Conclusion

CT x-rays induce DNA damage in paediatric patients even at low doses and the level of DNA damage is reduced by application of more effective CT dose reduction techniques and paediatric protocols.

Key Points

• CT induces a small, significant number of double-strand DNA breaks in children.

• More effective CT dose reduction results in less DNA damage.

• Risk estimates based on the LNT hypothesis may represent underestimates.

The use of duplex doppler ultrasound in a case of multifocal hepatic hemangioma

A one-month-old girl presented with multiple cutaneous hemangiomas, abnormal weight gain, hepatomegaly, and symptoms of bleeding disorder. Abdominal ultrasound and CT revealed a multifocal hypervascular hepatic tumor and signs of vascular overload. Biopsy confirmed the presence of an infantile hepatic hemangioma. Conservative treatment with high dose steroids showed regression of the hepatic lesions and the signs of vascular congestion. Ultrasound was used for follow-up and its role in treatment monitoring is discussed in this manuscript.

Nonfunctioning neuroendocrine tumor of the pancreas in an 8-year-old girl

We report a case of a nonfunctioning neuroendocrine pancreatic tumor in the pediatric age group. An 8-year-old child complains of vague abdominal pain and radiological investigations detect a tumoral mass in the pancreatic tail. Abdominal ultrasound, contrast enhanced computed tomography and magnetic resonance imaging demonstrate a round intrapancreatic solid moderately vascularized lesion of approximately 5 cm in diameter, with a smooth contour and well demarcated from the surrounding tissues. After surgical resection, the diagnosis of a hormonally inactive benign neuroendocrine tumor is histologically diagnosed. Patient's follow-up is uneventful.

Cervical ectopic thymus presenting as a painless neck mass in a child

Ectopic cervical thymus is an uncommon entity to be considered in the differential diagnosis of neck masses in infants and children. The sonographic appearance of a hyporeflective mass with characteristic internal linear hyperreflections situated along the path of the thymopharyngeal duct should suggest diagnosis. On MRI, signal intensities differ significantly from other more common neck mass lesions in children such as a branchiogenic cyst, hemangioma and lymphangioma. Diagnosis can be confirmed by performing a sonographically guided thru-cut biopsy.

Accuracy of magnetic resonance imaging for measuring fetal sheep lungs and other organs

OBJECTIVE

Lung volume measurement by fetal magnetic resonance imaging (fetMRI) has been used to predict survival of fetuses with isolated congenital diaphragmatic hernia (CDH). So far, the accuracy and precision of fetMRI for volumetry of either the normal or hypoplastic developing lung has not been formally studied.

METHODS

A total of nine sheep carrying 14 fetuses underwent fetMRI under general anesthesia at a mean of 118 days' gestational age (term = 145 days). A total of 61 organs were measured in nine normal fetal sheep and five that underwent surgical creation of diaphragmatic hernia (DH), so as to induce pulmonary hypoplasia. Lungs were measured on T2-WI (weighted images) in three different planes, while liver and kidneys were measured in the axial (T1-WI) and sagittal (T2-WI) planes, respectively. Necropsy was done within 24 h after fetMRI to determine the volume postmortem by the water displacement method. Values were linearly correlated and a Bland and Altman analysis was done for volume measurement comparison, calculating means +/- SD, bias (mean of the difference of volume measurements), precision (SD of the difference) and absolute and proportionate limits of agreement for both methods. The accuracy of fetMRI volume measurement was determined for different organ groups by calculating the median relative error and precision index, both being measures of error in proportion to the magnitude of the volume measured, as a clinically relevant proxy of potential errors.

RESULTS

The fetMRI volume measurements were on average larger than postmortem volumes, except for the kidneys. Kidney volume determination had a relative error of 29%, while measurements of larger organs had larger relative errors (42% for liver). Normal lungs were less accurately measured in the coronal or sagittal than in the axial plane (relative error 53%, 73% and 38%, respectively; P < 0.05 for sagittal vs. axial). Axially-measured lung volumes were more accurate for lungs of normal sheep compared to DH lungs (relative error 38% vs. 73%, respectively; P < 0.05).

CONCLUSION

FetMRI measured systematically higher volumes for organs such as fetal liver or lung. This may be related to fluid loss or lack of perfusion at the time of necropsy. Measurement of lung volume by fetMRI was most accurate in the axial plane. Measurements of lung and liver volumes by fetMRI in normal sheep were both in agreement with volumes measured at necropsy. Loss of accuracy for DH-lungs in comparison with the accuracy when measuring other similarly small organs, such as kidneys, suggests that fetMRI measurements can be less accurate for hypoplastic lungs related to CDH. With improving hardware, it might become easier to render the fetal lung and determine its volume reliably.

The use of methohexital during chest tube removal in neonates

BACKGROUND

The aim of the study was the evaluation of the effect of methohexital during chest tube removal (CTR) in neonates.

METHODS

Evaluation was based on the degree of sedation (grades 1-4) and relaxation (grades 1-4) and trends in vital signs heart rate, mean arterial blood pressure (MAP), oxygen saturation at time points (-10, -5, -3, -1, 0, 1, 3, 5, and 10 min) before and after administration of methohexital. A multidimensional pain scale [Leuven Neonatal Pain Scale (LNPS)] was used to evaluate pain expression. Effective sedation and relaxation (grade >2) would enable the physician to perform CTR without difficulties. Paired Wilcoxon was used to compare vital signs and pain expression before and after the procedure.

RESULTS

Twenty-two procedures in 22 infants were recorded. Eleven infants were ventilated and 21 infants were having intravenous analgesics during CTR. Birth weight was 2645 g (range 1235-4500 g). Postnatal age was 6 days (range 1-80 days). Methohexital had no effect on ventilatory weaning, MAP or oxygen saturation. Heart rate increased from 144 (49) to 162 (43) (P = 0.012) b.min(-1). Sedation and relaxation were effective (>grade 2) and lasted for <5 min. No major side effects were documented. Adequate analgesia by LNPS was more difficult to evaluate as clinical pain evaluation was not feasible during full muscular relaxation.

CONCLUSIONS

Administration of methohexital for CTR resulted in adequate sedation and relaxation without major side effects in neonates. This approach should be compared with other strategies.

The value of fast MR imaging as an adjunct to ultrasound in prenatal diagnosis

The aim of this study was to evaluate the role of MR imaging of the fetus to improve sonographic prenatal diagnosis of congenital anomalies. In 40 fetuses (not consecutive cases) with an abnormality diagnosed with ultrasound, additional MR imaging was performed. The basic sequence was a T2-weighted single-shot half Fourier (HASTE) technique. Head, neck, spinal, thoracic, urogenital, and abdominal fetal pathologies were found. This retrospective, observational study compared MR imaging findings with ultrasonographic findings regarding detection, topography, and etiology of the pathology. The MR findings were evaluated as superior, equal to, or inferior compared with US, in consent with the referring gynecologists. The role of these findings in relation to pregnancy management was studied and compared with postnatal follow-up in 30 of 40 babies. Fetal MRI technique was successful in 36 of 39 examinations and provided additional information in 21 of 40 fetuses (one twin pregnancy with two members to evaluate). More precise anatomy and location of fetal pathology (20 of 40 cases) and additional etiologic information (8 of 40 cases) were substantial advantages in cerebrospinal abnormalities [ventriculomegaly, encephalocele, vein of Galen malformation, callosal malformations, meningo(myelo)cele], in retroperitoneal abnormalities (lymphangioma, renal agenesis, multicystic renal dysplasia), and in neck/thoracic pathology [cervical cystic teratoma, congenital hernia diaphragmatica, congenital cystic adenomatoid lung malformation (CCAM)]. This improved parental counseling and pregnancy management in 15 pregnancies. In 3 cases, prenatal MRI findings did not correlate with prenatal ultrasonographic findings or neonatal diagnosis. The MRI provided a more detailed description and insight into fetal anatomy, pathology, and etiology in the vast majority of these selected cases. This improved prenatal parental counseling and postnatal therapeutic planning.

Pediatric emergencies: thoracic emergencies

Emergencies always require rapid diagnosis and an urgent or semi-urgent medical, interventional, or surgical action. In most cases radiology plays an essential role in making an accurate diagnosis. Reviewing the causes of acute respiratory pathology in the different pediatric age groups, we thought it would be interesting to divide the pathologies into two main parts: one part concerning pathologies involving the air flow and the other part concerning pathology affecting the pulmonary parenchyma. We acknowledge, however, that both conditions can occur concomitantly. The esophagus is another anatomic structure in the thorax that can be responsible for acute pathology in children. Acute pathology predominantly involving the air flow can be intrinsic and/or extrinsic, affecting the upper airways, trachea, main and segmental bronchi, and the small airways. Acute lung pathology can be congenital, infectious, or less frequently, tumoral or traumatic in children. Pleural pathology and cardiogenic emergencies are discussed also. Acute esophageal pathology is discussed briefly.

Inflammatory pseudotumor of the lung

Inflammatory pseudotumor is the most frequent primary lung tumor in children under the age of 16. Clinical history and radiological diagnosis are often non-specific, making diagnosis uneasy. In some instances, only surgery can provide a definite diagnosis. However, when dealing with a solitary mass of the lung in an infant the radiologists should always include inflammatory pseudotumor among the entities of the differential diagnosis. This case report discusses the radiological features of inflammatory pseudotumors.

Multicystic kidney dysplasia: a prospective study on the natural history of the affected and the contralateral kidney

In a 6-year period, 41 young infants with multicystic kidney dysplasia were seen in our department. In 30 cases, the diagnosis had already been suspected by prenatal ultrasonography. A prospective protocol was proposed to the parents which comprised ultrasound evaluation every 3 months until the age of 24 months and renal function assessment at the age of 18 months. In 33 patients, the study was completed as scheduled. At the start of the study, the maximal diameter of the multicystic kidney was above the mean length of normal kidneys in all cases where precise measurement was possible. Within 24 months, 7 of the dysplastic kidneys disappeared, 20 regressed in size, 1 remained unchanged and only 5 increased in size. Between the age of 0 to 3 months, renal length of the contralateral kidney was within the normal range in 19 infants and above +2SD in 14 cases. At the age of 18 to 24 months, renal length was, with few exceptions, between 0 and +4SD. Inulin clearance was normal in all 33 individuals with a median value of 112 ml/min per 1.73 m2.

CONCLUSION

As a rule, multicystic kidneys shrink in the first 2 years of life. In most cases the contralateral kidney maintains a normal renal function as a consequence of progressive compensatory hypertrophy.

Treatment of Pseudomonas aeruginosa lung infection in cystic fibrosis with high or conventional doses of ceftazidime

In cystic fibrosis patients with Pseudomonas aeruginosa colonization and increasing pulmonary infection, ceftazidime 150 mg/kg/day was compared with 320 mg/kg/day. Changes in clinical findings, laboratory tests, pulmonary function and chest radiographs were evaluated after 14 days of treatment in hospital. Both treatments were associated with a significant improvement, but the higher dose did not offer an additional benefit. An increase in alanine aminotransferase (ALT) occurred after both treatments; with a significantly greater increase after the high-dose therapy (mean increase +/- S.E.M. 8% +/- 2% vs 2% +/- 1 %; P < 0.01). All but one of the ALT values after treatment were within normal limits.

Caroli's syndrome

We report the case of a two-year-old girl presenting with recurrent episodes of fever and hepatomegaly. High resolution ultrasound (US) and computed tomography (CT) of the liver show dilated intrahepatic bile ducts with bridge formation and intraluminal protrusions. The extrahepatic bile duct is normal. The diagnosis of irregular dilated bile ducts with signs of cholangitis and cholangiolitis is proved by liver biopsy. The histologically associated congenital liver fibrosis in our patient enter into the Caroli's syndrome. We illustrate the high resolution US and the CT findings in this case.

Bronchopulmonary dysplasia: correlation of radiographic and clinical findings

BACKGROUND AND PURPOSE

Abnormalities of the chest wall have been described in bronchopulmonary dysplasia (BPD). Clinical, radiographic and pulmonary function variables were evaluated in 1-year-old children ventilated because of neonatal lung disease in order to quantify these thoracic changes and to evaluate the lung disease.

METHODS

The pulmonary status of 51 infants with neonatal lung disease requiring artificial ventilation was reevaluated clinically and radiographically at the age of 1 year. Twenty-two of these infants had developed BPD. Thoracic depth and width were measured clinically and on chest X-ray. The Toce score evaluated the presence of cardiomegaly, hyperinflation, emphysema and interstitial lung disease. Lung function was measured after sedation using previously reported methods. In BPD patients, Toce score and lung function were determined and compared at 1 month and at 1 year of age.

RESULTS

In BPD patients, chest depth was significantly smaller when measured clinically as well as on chest radiograph (P < 0.05; Mann-Whitney U-test). There was a statistically significant correlation between chest depth measured clinically and on chest X-ray. Toce score was significantly higher in BPD patients (P < 0.05). In BPD patients intersitial abnormalities and decreased lung compliance were more frequent at the age of 1 month than at the age of 1 year. At the age of 1 year, hyperinflation was more frequent and at that time increased airway resistance was still noted. Thus the type of X-ray abnormality reflects the type of lung function disturbance.

CONCLUSION

The flatness of the chest is most likely a consequence of the long-standing lung function abnormalities.

The Holt-Oram syndrome: radiological approach

The clinical and radiological findings in a female child with Holt-Oram syndrome are reported. The most important features are cardiac anomalies associated with typical anomalies of the skeleton of the forearms.

High-dose growth hormone treatment of short children born small for gestational age

The effect of GH administration was evaluated over 2 yr in 50 short, prepubertal, non-GH deficient children born small for gestational age, who had been randomly allocated to a group receiving no treatment or daily sc GH treatment at a dose of 0.2 or 0.3 IU/kg. At the start of the study, mean age was 5.2 yr, bone age was 4.0 yr, height SDS was -3.5, height velocity SDS was -0.8, weight SDS was -2.7, and body mass index SDS was -1.9. Catch-up growth was observed in none of the untreated and all of the treated children. The response to GH treatment included a near doubling of growth velocity and of weight gain and a mean height increment of more than 2 SDS. GH treatment was associated with a distinct acceleration of bone maturation. The differences between the growth responses evoked by the two GH doses were minor. The prepubertal GH-induced catch-up growth was associated with elevated serum concentrations of insulin, insulin-like growth factor-I, insulin-like growth factor binding protein-3, and osteocalcin, whereas insulin-like growth factor-II levels remained unaltered. GH treatment was well tolerated. In conclusion, high-dose GH administration over 2 yr is emerging as a potential therapy to increase the short stature that results from insufficient catch-up growth in young children born small for gestational age. The long-term impact of this approach remains to be delineated.

Mesenchymal hamartoma: radiological differentiation from other possible liver tumors in childhood

We report a case of hepatic mesenchymal hamartoma in a young boy. The clinically huge abdominal mass was demonstrated on ultrasound and computed tomography as a cystic, minimally vascularized tumor, attached to the liver. The mass was surgically removed.

Localized brain proton NMR spectroscopy in young adult phenylketonuria patients

Localized proton magnetic resonance spectroscopy with short echo time (TE = 20 ms) was used to investigate biochemical changes in the cerebral white matter of 20 young adult patients (median 19 years) with phenylketonuria (PKU). Results were compared with those of a group of 12 age-matched healthy volunteers (median 25 years). Concentrations of N-acetyl-aspartate (NAA) and choline (Cho) relative to creatine (Cr) were unchanged. However, concentrations of inositol (Ins) relative to creatine were found to be significantly lower (P < 0.001) in the PKU patients (0.30 +/- 0.09 versus 0.57 +/- 0.17). Individual inositol concentrations did not correlate with age, diet, serum phenylalanine (Phe) levels or extent of pathological regions in the T2-weighted images. The lack of correlation with individual data suggests that the decreased inositol concentration could be related to a metabolic deficiency during fetal development. No signal from the phenyl ring protons of phenylalanine was detected in the PKU patients (phenylalanine serum concentration < or = 1.27 mM), which suggests that concentration of phenylalanine may be lower in brain than in serum.

Late-onset Bochdalek hernia with a rare postoperative complication: case report

We report a case of a 7-year-old-girl with a late-presenting Bochdalek hernia. The postoperative course was complicated by splenic torsion and subsequent total splenic infarction. Total splenic infarction due to splenic torsion has been reported in children with "wandering spleen" and in incarcerated Bochdalek hernias, but to our knowledge, not as a postoperative complication of Bochdalek hernia repair.