Radiological and surgical correlation of pelviureteric junction obstruction in positional anomalies of the kidney in children.

Pelviureteric junction obstruction, also known as ureteropelvic junction obstruction, is a congenital narrowing of the urinary excretory tract at the junction between the renal pelvis and the ureter and is a common cause of congenital pelvicalyceal dilatation. The outcome is variable, from spontaneous resolution to renal parenchymal function loss in cases of untreated high-grade obstruction. Abnormalities in renal ascent, rotation and vascularity can be associated with pelviureteric junction obstruction and easily overlooked radiologically. In this pictorial review, we explore the anatomical, radiological and surgical correlations of pelviureteric junction obstruction in the context of a normal kidney and a spectrum of renal abnormalities, including hyper-rotation (also known as renal malrotation), failed renal ascent, fusion anomalies and accessory crossing renal vessels. For each scenario, we provide technical tips on how to identify the altered anatomy at the first ultrasound assessment and correlation with scintigraphic, cross-sectional and postoperative imaging where appropriate. A detailed ultrasound protocol specifically to assess and characterise pelviureteric junction obstruction in paediatric patients is also offered.

Abdominal US in Pediatric Inflammatory Multisystem Syndrome Associated with SARS-CoV-2 (PIMS-TS).

Background Children with pediatric inflammatory syndrome temporally associated with SARS-CoV-2 (PIMS-TS), also known as multisystem inflammatory syndrome in children, present with abdominal pain among other nonspecific symptoms. Although initial imaging features of PIMS-TS have been reported, the duration of sonographic features remains unknown. Purpose To describe the abdominal US features of PIMS-TS at initial presentation and follow-up. Materials and Methods A retrospective review of children and young adults presenting with clinical features suspicious for PIMS-TS between April 2020 and June 2021 was carried out. US features were documented and reviewed at initial presentation and follow-up. Descriptive statistics were used and interobserver variability was calculated. Results Of 140 children and young adults presenting with suspected PIMS-TS, 120 had confirmed PIMS-TS (median age, 9 years; interquartile range, 7-12 years; 65 male patients) and 102 underwent abdominal US at presentation. PIMS-TS was present as a single abnormality in 109 of the 120 patients (91%) and abdominal symptoms were present in 104 of the 109 (95%). US examinations were abnormal in 86 of 102 patients (84%), with ascites being the most common abnormality in 65 (64%; 95% CI: 54, 73). Bowel wall thickening was present at US in 14 of the 102 patients (14%; 95% CI: 7, 20) and mesenteric inflammation was present in 16 (16%; 95% CI: 9, 23); all of these patients presented with abdominal symptoms. Among the patients with bowel wall thickening, the distal and terminal ileum were most involved (eight of 14 patients, 57%). Abdominal symptoms decreased to seven of 56 patients (13%) in those followed up at 6 months. Thirty-eight patients underwent follow-up US, and the presence of bowel inflammation had decreased to three of 27 patients (11%; 95% CI: -1, 23) in those followed up for less than 2 months and 0 of 17 (0%) in those followed up for more than 2 months. Conclusion Of 102 patients with pediatric inflammatory multisystem syndrome temporally associated with SARS-CoV-2 who underwent US at presentation, 14 (14%) had abdominal US findings of bowel inflammation and 16 (16%) had mesenteric edema. All US abnormalities resolved after 2 months. © RSNA, 2022 Online supplemental material is available for this article. See also the editorial by van Rijn and Pajkrt in this issue.

Incidence of Deflux® calcification masquerading as distal ureteric calculi on ultrasound.

OBJECTIVE: Dextranomer-hyaluronic acid (Deflux(®)), the most widely used compound in the endoscopic treatment of vesico-ureteric reflux (VUR) today, is believed to provoke only minimal inflammation. Reports of calcification of Deflux(®) are increasing. We ascertain the incidence of Deflux(®) calcification appearing as distal ureteric calculi on ultrasound. METHODS: Three cases (2 external patients) of ureteroscopy for calcified submucosal Deflux(®) prompted a retrospective review of the notes and imaging of all children treated with Deflux(®) for VUR between December 2000 and January 2011 at Great Ormond Street Hospital. RESULTS: 232 children (M:F = 5:3) received Deflux(®) for VUR at median age 2 years (range 2 months-12 years). Follow-up annual ultrasound, performed in all, identified calcification in 2. The interval between Deflux(®) injection and presentation of its calcification was 4 years. 104 of the 232 children had been followed up for 4-10 years. Considering the observed lag-period, after 4 years the incidence of calcification of Deflux(®) on ultrasound was 2% (2/104). CONCLUSIONS: Patients should be warned that calcification of Deflux(®) can occur. Misinterpretation as ureteric stones is common and may lead to unnecessary ureteroscopy. In this series, the incidence of calcification of Deflux(®) on ultrasound after 4 years was 2%.

Growth in PHEX-associated X-linked hypophosphatemic rickets: the importance of early treatment.

Inactivating mutations in phosphate-regulating endopeptidase (PHEX) cause X-linked hypophosphatemic rickets (XLHR) characterized by phosphaturia, hypophosphatemia, bony deformities, and growth retardation. We assessed the efficacy of combined calcitriol and orally administered phosphate (Pi) therapy on longitudinal growth in relation to age at treatment onset in a retrospective, single-center review of children with XLHR and documented PHEX mutations. Growth was compared in those who started treatment before (G1; N = 10; six boys) and after (G2; N = 13; five boys) 1 year old. Median height standard deviation score (HSDS) at treatment onset was normal in G1: 0.1 [interquartile range (IR) -1.3 to 0.4) and significantly (p = 0.004) lower in G2 (IR -2.1 (-2.8 to -1.4). Treatment duration was similar [G1 8.5 (4.0-15.2) vs G2 11.9 (6.2-14.3) years; p = 0.56], as were prescribed phosphate and calcitriol doses. Recent HSDS was significantly (p = 0.009) better in G1 [-0.7 (-1.5 to 0.3)] vs G2 [-2.0 (-2.3 to -1.0)]. No effects of gender or genotype on growth could be identified. Children with PHEX-associated XLHR benefit from early treatment and can achieve normal growth. Minimal catchup growth was seen in those who started treatment later. Our findings emphasize the importance of early diagnosis to allow treatment before growth has been compromised.

Multicystic dysplastic kidney and cystic accessory uterine cavity: a new prenatally diagnosed association.

The co-existence of renal and mullerian anomalies is well-recognised. Multicystic dysplastic kidneys (MCDK) are known to be associated with the presence of genital cysts in both males and females, but this is the first report of a prenatally diagnosed MCDK associated with a non-communicating cystic uterine cavity. The management of these abnormalities in childhood is not well-established.

Postmortem MRI of bladder agenesis.

We report a 35-week preterm neonate with bladder agenesis and bilateral dysplastic kidneys. A suprapubic catheter was inadvertently inserted into one of the larger inferior cysts of the left dysplastic kidney. A postmortem MRI scan was performed with the findings being confirmed on autopsy. We are unaware of another postmortem MRI study demonstrating bladder agenesis.

Imaging of the urinary tract: the role of CT and MRI.

Computed tomography (CT) and magnetic resonance imaging (MRI) are increasingly valuable tools for assessing the urinary tract in adults and children. However, their imaging capabilities, while overlapping in some respects, should be considered as complementary, as each technique offers specific advantages and disadvantages both in actual inherent qualities of the technique and in specific patients and with a specific diagnostic question. The use of CT and MRI should therefore be tailored to the patient and the clinical question. For the scope of this article, the advantages and disadvantages of these techniques in children will be considered; different considerations will apply in adult practice.

Gastrointestinal tract imaging in children: current techniques.

Imaging of the gastrointestinal (GI) tract in children continues to evolve, with new techniques, both radiological and non-radiological, being added to the repertoire. This article provides a summary of current imaging techniques of the GI tract (primarily the upper GI tract) and the relationship between those techniques. It covers the upper GI series and other contrast studies, US, CT and MRI. Note is also made of the contribution now made by capsule endoscopy (CE). Abdominal emergency imaging is not covered in this article.

The predictive value of a repeat micturating cystourethrogram for remnant leaflets after primary endoscopic ablation of posterior urethral valves.

OBJECTIVE: We routinely perform a cystourethroscopy 3 months after initial ablation of posterior urethral valves. The aim of this study was to determine the predictive value of the urethral appearance on preoperative micturating cystourethrogram (MCUG) for further valve resection at check cystoscopy. PATIENTS AND METHODS: We retrospectively reviewed 31 consecutive boys (aged 4-18 months) who underwent check cystoscopy and repeat MCUG between 2006 and 2008. RESULTS: Repeat MCUG suggested remnant valves in 10, but no residual leaflets were identified cystoscopically in 4. In 20 boys, the valves appeared completely ablated on MCUG but valve leaflets received further resection in 10. One study was undiagnostic. Residual valves were resected in 83% (5/6) where valves and urethral dilatation were noted on MCUG. Where MCUG suggested either valves or persistent dilatation alone, further resection occurred in 40% (4/10). Remnant leaflets were also present in half of those (7/14) in whom the repeat MCUG had shown complete ablation and resolved/reduced posterior urethral dilatation. CONCLUSIONS: The positive predictive value of valve leaflets and/or posterior urethral dilatation on repeat MCUG for subsequent resection of valve remnants was 56%; the negative predictive value was 50%. We found repeat MCUG alone imprecise in excluding residual valve tissue and recommend check cystoscopy in all.

Mild controlled hypothermia in preterm neonates with advanced necrotizing enterocolitis.

OBJECTIVES: Necrotizing enterocolitis (NEC) with multiple organ dysfunction syndrome (MODS) carries significant morbidity and mortality. There is extensive experimental evidence to support investigation of therapeutic hypothermia in infants with these conditions. We aimed to establish the feasibility and safety of mild hypothermia in preterm neonates with NEC and MODS as a prelude to a randomized trial. METHODS: This was a prospective, nonrandomized pilot study of 15 preterm infants who were referred for surgical intervention of advanced NEC and failure of at least 3 organs. Whole-body cooling was achieved by ambient temperature adjustment with or without cooling mattress. Three groups (n = 5 per group) were cooled to core temperatures of 35.5 degrees C (+/-0.5 degrees C), 34.5 degrees C, and 33.5 degrees C, respectively, for 48 hours before rewarming to 37 degrees C. Infants were carefully assessed to identify adverse effects that potentially were related to cooling and rewarming. A noncooled group (n = 10) with advanced surgical NEC and MODS was used for comparison. Data are medians (interquartile range). RESULTS: Gestational age at birth was 27 weeks (26-30), admission weight was 1.1 kg (1.0-1.7), and admission age was 31 days (12-45). Core temperature was maintained within target range for 90% (88%-97%) of the intended time. Statistically significant relationships were identified between core temperature and heart rate (P < .0001), pH (P < .0001), base excess (P = .003), and blood clot dynamics (longer time to initial clot formation, slower rate of clot formation, and decrease in clot strength; all P < .001) as assessed by thromboelastography. No major clinical problems or adverse events were noted during cooling or rewarming. Comparison with the noncooled group revealed no increase in mortality, bleeding, infection, or need for inotropes in infants who were cooled. CONCLUSIONS: Mild hypothermia for 48 hours in preterm neonates with severe NEC seems both feasible and safe. Additional investigation of the efficacy of this therapeutic intervention in this population is warranted.

Is necrotizing enterocolitis associated with development or progression of intraventricular hemorrhage?

An association between necrotizing enterocolitis (NEC) and poor neurodevelopmental outcome is increasingly recognized. A progression of preexisting intraventricular hemorrhage (IVH) or new IVH during an episode of NEC may be contributory. We investigated the incidence of IVH in infants with NEC. We performed an observational study of 105 infants with acute NEC during a 3-year period. Cranial ultrasound scans were performed on admission, following surgery, and following periods of clinical instability. Median birth weight was 0.92 kg (interquartile range, 0.73 to 1.56), gestational age 27 weeks (interquartile range, 25 to 30), and age at admission 14 days (interquartile range, 6 to 32). Twenty-five infants had an IVH before developing NEC. Eighty-one had Bell stage III disease, and 84 required surgery. Four infants developed a new IVH during the episode of NEC and all four died. IVH during an episode of NEC is rare even in very sick babies but carries a poor prognosis. IVH during an episode of NEC is unlikely to account for the poor neurodevelopmental outcome in this group as a whole.

Dialysis accelerates medial vascular calcification in part by triggering smooth muscle cell apoptosis.

BACKGROUND: Vascular calcification is associated with increased morbidity and mortality in stage V chronic kidney disease, yet its early pathogenesis and initiating mechanisms in vivo remain poorly understood. To address this, we quantified the calcium (Ca) load in arteries from children (10 predialysis, 24 dialysis) and correlated it with clinical, biochemical, and vascular measures. METHODS AND RESULTS: Vessel Ca load was significantly elevated in both predialysis and dialysis and was correlated with the patients' mean serum Ca x phosphate product. However, only dialysis patients showed increased carotid intima-media thickness and increased aortic stiffness, and calcification on computed tomography was present in only the 2 patients with the highest Ca loads. Importantly, predialysis vessels appeared histologically intact, whereas dialysis vessels exhibited evidence of extensive vascular smooth muscle cell (VSMC) loss owing to apoptosis. Dialysis vessels also showed increased alkaline phosphatase activity and Runx2 and osterix expression, indicative of VSMC osteogenic transformation. Deposition of the vesicle membrane marker annexin VI and vesicle component mineralization inhibitors fetuin-A and matrix Gla-protein increased in dialysis vessels and preceded von Kossa positive overt calcification. Electron microscopy showed hydroxyapatite nanocrystals within vesicles released from damaged/dead VSMCs, indicative of their role in initiating calcification. CONCLUSIONS: Taken together, this study shows that Ca accumulation begins predialysis, but it is the induction of VSMC apoptosis in dialysis that is the key event in disabling VSMC defense mechanisms and leading to overt calcification, eventually with clinically detectable vascular damage. Thus the identification of factors that lead to VSMC death in dialysis will be of prime importance in preventing vascular calcification.

Airway wall thickening and emphysema show independent familial aggregation in chronic obstructive pulmonary disease.

RATIONALE: It is unclear whether airway wall thickening and emphysema make independent contributions to airflow limitation in chronic obstructive pulmonary disease (COPD) and whether these phenotypes cluster within families. OBJECTIVES: To determine whether airway wall thickening and emphysema (1) make independent contributions to the severity of COPD and (2) show independent aggregation in families of individuals with COPD. METHODS: Index cases with COPD and their smoking siblings underwent spirometry and were offered high-resolution computed tomography scans of the thorax to assess the severity of airway wall thickening and emphysema. MEASUREMENTS AND MAIN RESULTS: A total of 3,096 individuals were recruited to the study, of whom 1,159 (519 probands and 640 siblings) had technically adequate high-resolution computed tomography scans without significant non-COPD-related thoracic disease. Airway wall thickness correlated with pack-years smoked (P < or = 0.001) and symptoms of chronic bronchitis (P < 0.001). FEV(1) (expressed as % predicted) was independently associated with airway wall thickness at a lumen perimeter of 10 mm (P = 0.0001) and 20 mm (P = 0.0013) and emphysema at -950 Hounsfield units (P < 0.0001). There was independent familial aggregation of both the emphysema (adjusted odds ratio, 2.1; 95% confidence interval, 1.1-4.0; P < or = 0.02) and airway disease phenotypes (P < 0.0001) of COPD. CONCLUSIONS: Airway wall thickening and emphysema make independent contributions to airflow obstruction in COPD. These phenotypes show independent aggregation within families of individuals with COPD, suggesting that different genetic factors influence these disease processes.

The circulating calcification inhibitors, fetuin-A and osteoprotegerin, but not matrix Gla protein, are associated with vascular stiffness and calcification in children on dialysis.

BACKGROUND: Vascular calcification occurs in the majority of patients with chronic kidney disease, but a subset of patients does not develop calcification despite exposure to a similar uraemic environment. Physiological inhibitors of calcification, fetuin-A, osteoprotegerin (OPG) and undercarboxylated-matrix Gla protein (uc-MGP) may play a role in preventing the development and progression of ectopic calcification, but there are scarce and conflicting data from clinical studies. METHODS: We measured fetuin-A, OPG and uc-MGP in 61 children on dialysis and studied their associations with clinical, biochemical and vascular measures. RESULTS: Fetuin-A and OPG were higher and uc-MGP lower in dialysis patients than controls. In controls, fetuin-A and OPG increased with age. Fetuin-A showed an inverse correlation with dialysis vintage (P = 0.0013), time-averaged serum phosphate (P = 0.03) and hs-CRP (P = 0.001). Aortic pulse wave velocity (PWV) and augmentation index showed a negative correlation with fetuin-A while a positive correlation was seen with PWV and OPG. Patients with calcification had lower fetuin-A and higher OPG than those without calcification. On multiple linear regression analysis Fetuin-A independently predicted aortic PWV (P = 0.004, beta = -0.45, model R(2) = 48%) and fetuin-A and OPG predicted cardiac calcification (P = 0.02, beta = -0.29 and P = 0.014, ss = 0.33, respectively, model R(2) = 32%). CONCLUSIONS: This is the first study to define normal levels of the calcification inhibitors in children and show that fetuin-A and OPG are associated with increased vascular stiffness and calcification in children on dialysis. Higher levels of fetuin-A in children suggest a possible protective upregulation of fetuin-A in the early stages of exposure to the pro-calcific and pro-inflammatory uraemic environment.

Follow-up imaging after laparoscopic heminephrectomy in children.

BACKGROUND: The radiological findings after laparoscopic heminephrectomy in children are not widely reported. OBJECTIVE: To document the range of imaging appearances following laparoscopic heminephrectomy in children. MATERIALS AND METHODS: We reviewed all imaging and all radiology reports performed on children in our institution who had undergone laparoscopic heminephrectomy over a 6-year period. RESULTS: Between 2001 and 2007, 35 patients (24 girls, 11 boys) had laparoscopic heminephrectomy. The mean age at surgery was 3.5 years. The sites of surgery comprised 12 right upper, 5 right lower, 18 left upper and 3 left lower heminephrectomies. These numbers included three patients who had bilateral procedures. The most consistent postoperative finding was an avascular cyst related to the site of surgery, seen after 23 of 38 procedures. Of these 23 cysts, 13 were simple and 10 were septated and/or contained echogenic debris. CONCLUSION: A cyst related to the site of laparoscopic heminephrectomy is a frequent postoperative occurrence but is not widely recognized for being simply this. Simple, anechoic, and septated appearances are possible. This cyst may be confusing to the radiologist and the clinician if they are not aware of the history of laparoscopic heminephrectomy and the technique that has been used. Whilst the exact aetiology of this cystic lesion is uncertain, all the patients in our series had a heminephrectomy performed with the use of an Endoloop (Ethicon, Somerville, NJ). No patients have required intervention to date.

A bimodal association of vitamin D levels and vascular disease in children on dialysis.

In addition to its classical role in calcium-phosphate homeostasis, vitamin D has anti-inflammatory effects that may influence vascular disease. This study examined the impact of vitamin D levels on the vascular phenotype in 61 children who had been on dialysis for >or=3 mo and in 40 age-matched control subjects. All dialysis patients were prescribed daily oral 1-alpha hydroxyvitamin D(3). 92% of patients were deficient in 25-hydroxyvitamin D [25(OH)D]. 1,25-dihydroxyvitamin D [1,25(OH)(2)D] levels were low in 36% and high in 11% of patients. There was a weak correlation between 1 alpha-hydroxyvitamin D(3) dosage and 1,25(OH)(2)D levels. Both carotid intima-media thickness and calcification scores showed a U-shaped distribution across 1,25(OH)(2)D levels: patients with both low and high 1,25(OH)(2)D had significantly greater carotid intima-media thickness (P < 0.0001) and calcification (P = 0.0002) than those with normal levels. Low 1,25(OH)(2)D levels were associated with higher high-sensitivity C-reactive protein (P < 0.0001). Calcification was most frequently observed in patients with the lowest 1,25(OH)(2)D and the highest high-sensitivity C-reactive protein. In contrast, 25(OH)D levels did not correlate with any vascular measure. In conclusion, both low and high 1,25(OH)(2)D levels are associated with adverse morphologic changes in large arteries, and this may be mediated through the effects of 1,25(OH)(2)D on calcium-phosphate homeostasis and inflammation. For optimization of strategies to protect the vasculature of dialysis patients, careful monitoring of 1,25(OH)(2)D levels may be required.

The role of dynamic magnetic resonance urography in complex neonatal hydrometrocolpos.

Urinary hydrometrocolpos is rarely diagnosed and is most often attributed to a persistent urogenital sinus or a cloaca. We report the case of a neonate in which the use of dynamic MRI allowed accurate preoperative diagnosis of urinary hydrometrocolpos secondary to ectopic drainage of a small left pelvic kidney, associated with a bicornuate uterus.