Whole-body magnetic resonance imaging for staging Langerhans cell histiocytosis in children and young adults.

INTRODUCTION: Radiographic skeletal survey (R-SS) is the standard imaging technique for the initial staging of Langerhans cell histiocytosis (LCH). Whole-body magnetic resonance imaging (WB-MRI) has been proposed as an effective, radiation-free alternative. METHODS: We prospectively assessed patients with LCH followed at three tertiary centers in Italy and Austria. Two national study protocols were independently designed, and data were then pooled to increase the power of their findings. R-SS and WB-MRI were performed at diagnosis and repeated at the follow-up to confirm the nature of the identified lesions and to study their evolution. RESULTS: Data from 67 patients were analyzed (52 from Italy and 15 from Austria). Compared to R-SS, WB-MRI identified 29 additional skeletal lesions in 14 patients (including two false-positive lesions). Two skeletal lesions were detected at R-SS and missed at WB-MRI (false negative). Per-lesion sensitivity rates were 78.6% (95% CI: 71.0-85.9) for R-SS and 98.4% (95% CI: 94.4-99.8) for WB-MRI, respectively. Based on WB-MRI findings, six patients would have been upstaged to a higher risk class than staging with R-SS. CONCLUSIONS: WB-MRI had a significantly higher detection rate for skeletal lesions compared to R-SS. Clinical and radiology expertise is required to avoid upstaging and overtreatment.

Ultrasonography as first line imaging for the diagnosis of positional plagiocephaly.

BACKGROUND: In the last years, numerous studies evaluated different tools for the diagnosis of positional plagiocephaly (PP). The purpose of this study was to evaluate ultrasonography (US) as a first line screening test of lambdoid sutural patency in child with PP and to compare our results with the literature. METHODS: All consecutive patients who referred to our Institute from January 2016 to October 2017 with the suspicion of PP, were included in the study and performed US examination of the lambdoid sutures. A 3-6-month clinical follow-up was performed by a pediatric neurosurgeon or a pediatrician to confirm the diagnosis of PP. RESULTS: Thirty-five children performed US examination and in all cases the diagnosis of PP was confirmed. No cases of anticipated suture fusion were examined during this period. The concordance between US findings and clinical exam follow-up was 100%. CONCLUSIONS: Ultrasonography of the lambdoid sutures represents an ideal first-line screening test and reliable alternative to other diagnostic techniques for lambdoid sutural patency in child with PP, being radiation free, fast and cheap.

Abdominal rhabdoid tumor presenting with symptomatic spinal epidural compression in a newborn. A case report.

The occurrence of an abdominal tumor invading the spinal canal and causing symptoms of epidural compression is rare in an infant, and exceptional at birth. Peripheral neuroblastic tumors are by far the most common cause. Emergency chemotherapy is commonly curative, though permanent sequelae are possible. Although other malignancies may be involved, no case of rhabdoid tumors at birth has been reported. We describe the case of a neonate who presented symptoms of spinal epidural compression at birth secondary to a rhabdoid tumor. As expected with this highly malignant tumor, the patient experienced a rapidly progressive clinical course and died within three months of diagnosis.

Presenting features of neuroblastoma with spinal canal invasion. A prospective study of the International Society of Pediatric Oncology Europe - Neuroblastoma (SIOPEN).

Introduction: Between 5 and 15% of children with neuroblastoma (NB) present with or develop spinal canal invasion (SCI). The majority of these children have symptoms of epidural compression of spinal cord and/or spinal nerves. Treatment of NB-SCI is considered an emergency but its modalities are not yet well-established. Independently of treatment, NB-SCI may result in significant long-term disabilities. We report on the first prospective study of NB-SCI focused on presenting characteristics of both symptomatic and asymptomatic patients and correlation between SCI-related symptoms and imaging features. Materials and methods: This SIOPEN prospective NB-SCI study opened in June 2014. Patient data including SCI symptoms evaluated by standardized measures and spinal cord imaging studies were collected for each patient. For the purpose of this study data entry was locked on July 2021. Results: Of the 208 NB-SCI patients registered, 196 were evaluable for this analysis of whom 67% were symptomatic and 33% asymptomatic. Median age was 11 months. The thorax was the commonest primary tumor site. The median intervals between initial symptoms and diagnosis and between first medical visit and diagnosis were 14 and 3 days, respectively. The was no statistical difference in frequency of presenting characteristics between symptomatic and asymptomatic patients. Presenting features of NB-SCI patients differed from other NBs for older median age, prevalence of thoracic vs. abdominal primary site, prevalence of localized vs. metastatic disease and lower incidence of MYCN gene amplification. The most common SCI features were motor deficit in the younger and pain in the older patients that correlated on imaging with both transverse and longitudinal extent but not with the level of intraspinal tumor. Spinal cord T2-hyperintensity was more frequently detected in symptomatic patients (not significant). Conclusion: This prospective study confirms that children with NB-SCI differ from NBs without SCI. Compared to previous studies, it provides more detailed information regarding presenting symptoms, time intervals between SCI symptoms, medical visit and diagnosis, and correlations between symptoms and imaging features.

Functional Magnetic Resonance Urography in Ureteropelvic Junction Obstruction: Proposal for a Pediatric Quantitative Score.

Background: Ureteropelvic junction obstruction (UPJO) is one of the most frequent causes of congenital hydronephrosis. It is essential to distinguish UPJO which needs surgical treatment. fMRU combines high quality morphological details of the kidney and excretory pathways with functional data. Objective: This study aims to introduce a new radiological score based on fMRU findings to be able to differentiate surgical from non-surgical kidneys. Materials and Methods: We retrospectively selected patients with hydronephrosis due to UPJO who underwent fMRU (January 2009-June 2018). A multidisciplinary team identified a list of fMRU morpho-functional predictive variables to be included in the analysis. To evaluate the role of different independent variables in predicting the outcome, a multivariable logistic regression model has been performed; the outcome variable was the surgical intervention. For each predictive variable, Odds Ratio and 95% Confidence Intervals were calculated. The likelihood ratio test was used to assess the significance of the variables. Using the regression model, we assigned a numerical value to each predictive variable, rounding up the beta-coefficients. The cut-off value of the total score was obtained from the ROC curve analysis. Results: A total of 192 patients were enrolled, corresponding to 200 pathological kidneys. All of them underwent fMRU; 135 were surgically treated, while 65 underwent ultrasound or MRU follow-up. Predictive variables significantly associated with surgery resulted to be the urographic phase, the presence of abnormal vessels, and a baseline anterior-posterior pelvic diameter >23 mm. Beta coefficients of the logistic regression model were then converted in scores. The ROC curve of the score showed high sensitivity (84.3%) and specificity (81.3%) with a cut-off > 2.5. Conclusions: We propose a new fMRU score able to identify surgical vs. non-surgical kidneys with UPJO.

Comparison of Qualitative and Quantitative Analyses of MR-Arterial Spin Labeling Perfusion Data for the Assessment of Pediatric Patients with Focal Epilepsies.

The role of MR Arterial-Spin-Labeling Cerebral Blood Flow maps (ASL-CBF) in the assessment of pediatric focal epilepsy is still debated. We aim to compare the Seizure Onset Zone (SOZ) detection rate of three methods of evaluation of ASL-CBF: 1) qualitative visual (qCBF), 2) z-score voxel-based quantitative analysis of index of asymmetry (AI-CBF), and 3) z-score voxel-based cluster analysis of the quantitative difference of patient's CBF from the normative data of an age-matched healthy population (cCBF). Interictal ASL-CBF were acquired in 65 pediatric patients with focal epilepsy: 26 with focal brain lesions and 39 with a normal MRI. All hypoperfusion areas visible in at least 3 contiguous images of qCBF analysis were identified. In the quantitative evaluations, clusters with a significant z-score AI-CBF ≤ −1.64 and areas with a z-score cCBF ≤ −1.64 were considered potentially related to the SOZ. These areas were compared with the SOZ defined by the anatomo-electro-clinical data. In patients with a positive MRI, SOZ was correctly identified in 27% of patients using qCBF, 73% using AI-CBF, and 77% using cCBF. In negative MRI patients, SOZ was identified in 18% of patients using qCBF, in 46% using AI-CBF, and in 64% using cCBF (p < 0.001). Quantitative analyses of ASL-CBF maps increase the detection rate of SOZ compared to the qualitative method, principally in negative MRI patients.

Bilateral adrenal primary tumor in Stage 4S neuroblastoma: The Italian experience and review of the literature.

Bilateral adrenal neuroblastoma (NB) is rare and is mainly stage 4S. Its incidence, presenting features, management, and outcome have not been fully defined yet. We searched the Italian NB Registry (RINB) for stage 4S NB infants with bilateral adrenal primary tumor to compare them with stage 4S NB with unilateral tumor. Between 1979 and 2016, the RINB enrolled 3731 NB patients aged 0-18 years including 317 infants (8.5%) diagnosed with stage 4S NB. Eleven/317 (3.5%) had a bilateral adrenal primary tumor (Group 1) and 190/317 (59.9%) had a unilateral tumor (Group 2). Group 1 infants were significantly younger (51 vs. 89 days) but were comparable with Group 2 for any other presenting features. In the absence of specific protocols, upfront treatment was based on symptoms, size of adrenal tumors, and biology, and consisted of observation in 5 cases, radiotherapy in one, chemotherapy in 2, and surgery in 3. Five/11 developed progression and 2 of them, both with MYCN amplification, died. The 5-year EFS rates of Group 1 and 2 were 54.5% vs. 73.3% (P=.14) and 5-year OSs were 81.8% and 89.4%, respectively (P=.44). Our data support the hypothesis that 4S NB infants with bilateral adrenal tumors can have favorable outcome with personalized therapeutic approach. The three patients with MYCN amplified tumor benefited from upfront aggressive chemotherapy, in accordance with current protocols. Because of the rarity of this intriguing form of neuroblastoma, collaborative prospective studies are warranted, especially in view of gaining a better insight on its biological and genetic features.

Surgical validation of functional magnetic resonance urography in the study of ureteral anomalies distal to the uretero-pelvic junction in a pediatric cohort.

BACKGROUND: Ureteral anomalies distal to the Uretero-Pelvic Junction (UPJ) belong to the wide spectrum of congenital anomalies of the kidney and urinary tract (CAKUT). They can cause severe obstruction requiring a detailed anatomical depiction to define the surgical approach. Up to date, ultrasonography, voiding cystourethrography and scintigraphy are considered the gold-standard diagnostic tools to study obstructive anomalies of the urinary tract, however, they do not provide accurate ureteral anatomical details. The aim of our study was to evaluate the concordance between functional magnetic resonance urography (fMRU) and intraoperative findings to define ureteral anomalies distal to UPJ. METHODS: Pediatric patients with ureteral anomalies distal to the UPJ who underwent surgery after performing fMRU were retrospectively collected. Surgical data were compared with radiological results. The concordance was assessed considering both pathological and non-pathological urinary tracts and was calculated by means of the Cohen's kappa coefficient. fMRU diagnostic accuracy was defined by sensitivity, specificity, and binomial exact confidence intervals. RESULTS: We included 46 patients. The sensitivity and specificity of fMRU were 98.0% and 83,3%; positive predictive value 90,4%, negative predictive value 96.2%. The concordance between surgical findings and fMRU was 92,3%, with a k Cohen's coefficient of 0.83 (excellent). CONCLUSIONS: Our study demonstrates the excellent agreement between fMRU and surgical findings in the definition of ureteral anomalies distal to the UPJ in children. Thus, it could be considered a valid imaging technique in the preoperative planning as it provides the surgeon with important information regarding the etiology and site of the obstruction.

Magnetic resonance urography of congenital abnormalities - what the radiologist needs to know.

Congenital abnormalities of the kidney and urinary tract include a wide range of malformations ranging from asymptomatic to life-threatening conditions. Although pediatric urogenital system imaging is based on the use of US (pre- and postnatal), voiding cystourethrography and scintigraphic study, magnetic resonance (MR) urography plays a fundamental role in the classification and management of congenital abnormalities of the kidney and urinary tract, giving an overview of the different clinical pictures, thanks to its panoramicity and high anatomical detail. In fact the anomalies of the urinary tract are phenotypically variable because they can affect simultaneously several segments of different embryonic derivation, with complex clinical pictures; they can appear both as isolated phenotypes or as complex malformative conditions, involving renal parenchyma, collecting system and bladder. A deep knowledge of this complex embryogenesis and its possible phenotypic patterns allows a correct interpretation of MR urography images. We describe the embryology and pathophysiology of congenital abnormalities of the kidney and urinary tract as well as MR urography technique and findings. Congenital abnormalities of the kidney and urinary tract are classified into four groups: (1) obstruction (proximal, middle and distal), (2) budding with respect to the Wolffian duct (site and number of ureter), (3) ascent and rotation (ectopia, malrotation and fusion of kidney) and (4) anomaly of metanephric differentiation (dysplasia, megapolicalycosis).

Diffusion-Weighted MRI in the Evaluation of Renal Parenchymal Involvement during Febrile Urinary Tract Infections in Children: Preliminary Data.

Background: Urinary tract infection (UTI) is the most common infection in pediatric-age patients. Acute pyelonephritis (PNA) represents a worrying situation in pediatric patients due to the risk of sepsis and long-term cicatricial consequences. The purpose of this retrospective study is to evaluate the diagnostic role of DW-MRI in relation to clinical data, to understand if there are any clinical parameters useful in identifying which patients should undergo it. Methods: According to inclusion and exclusion criteria, we enrolled 51 patients ≤15 years old admitted to our Institute between September 2012 and April 2020 with a febrile UTI who underwent DW-MRI evaluation. Clinical, laboratory and imaging data were collected. Statistical analysis was performed. Results: 34 of 51 patients with an fUTI (66.7%) showed signs of acute parenchymal involvement at DW-MRI evaluation. In 27 of these 34 (79.4%), DW-MRI showed multiple areas of pyelonephritis. A statistically significant relationship (p = 0.0004) between older age at admission and pyelonephritis was demonstrated. No statistically significant relationship was found between the other clinical, anamnestic and laboratory parameters and the outcome of DWI. Only two ultrasound examinations allowed the identification of pathological areas on the renal parenchyma. Conclusions: From these preliminary investigations, we can say that selecting the patients with fUTI on whom to perform a DW-MRI is difficult. Nevertheless, thanks to the low cost, the very rare need for sedation and the accuracy in identifying pyelonephritic areas, the use of DW-MRI in patients with febrile UTI seems recommendable.

Imaging of diseases of the vagina and external genitalia in children.

A wide range of congenital or acquired conditions, some pretty rare, may affect the vulva and vagina in children. Swelling, visible or palpable masses and abnormal discharges are common symptoms of conditions affecting the vulva and/or the lower genital tract. The majority of these diseases are benign. Ultrasonography is pivotal to elucidate the anatomical origin of these conditions and make the diagnosis. Magnetic resonance imaging can be relevant to improve diagnostic confidence and, if needed, to plan more accurate surgical treatment. The aim of this pictorial essay is to review the related imaging findings to help make radiologists familiar with these conditions.

Non-contrast-enhanced magnetic resonance angiography for detecting crossing renal vessels in infants and young children: comparison with contrast-enhanced angiography and surgical findings.

BACKGROUND: Knowing that ureteropelvic junction obstruction is due to a crossing renal vessel is essential in choosing the appropriate surgical treatment. OBJECTIVE: To evaluate the diagnostic accuracy of non-contrast magnetic resonance (MR) angiography in identifying crossing renal vessels in children younger than 4 years old with unilateral hydronephrosis. MATERIALS AND METHODS: A retrospective review of preoperative MR urography of children with unilateral hydronephrosis was conducted by two independent readers. The presence or absence of crossing renal vessels was identified and compared with surgical findings. RESULTS: Twenty-nine patients were included. The disagreement between MR angiography with and without contrast enhancement in detecting a crossing renal vessel was 8%. The disagreement between non-contrast-enhanced MR and surgical findings was 17%. The disagreement between contrast-enhanced MR angiography and surgical findings was 25%. The balanced triggered angiography without contrast enhancement had a sensitivity of 70% (95% confidence interval [CI]: 35-93%) and a specificity of 93% (95% CI: 66-100%). Contrast-enhanced MR angiography had a sensitivity of 56% (95% CI: 21-86%) and a specificity of 91%. (95% CI: 59-100%). CONCLUSION: MR without contrast enhancement may be a reliable, valid and safe alternative to contrast-enhanced MR angiography for identifying crossing renal vessels.

Comparative Study Between Functional MR Urography and Renal Scintigraphy to Evaluate Drainage Curves and Split Renal Function in Children With Congenital Anomalies of Kidney and Urinary Tract (CAKUT).

Background: Obstructive congenital anomalies of the kidney and urinary tract have a high risk of kidney failure if not surgically corrected. Dynamic renal scintigraphy is the gold standard technique to evaluate drainage curves and split renal function (SRF). Objectives: To compare functional magnetic resonance (MR) urography with dynamic renal scintigraphy in measuring volumetric SRF and in the classification of drainage curves in patients with congenital anomalies of the kidney and urinary tract. Materials and Methods: We retrospectively collected patients with hydroureteronephrosis or pelvicalyceal dilatation at renal ultrasound, who underwent both functional MR urography and dynamic renal scintigraphy (DRS) within 6 months. DRS studies were evaluated by a single nuclear medicine physician with a double reading. Functional MR urography renograms were blind evaluated twice by two radiologists. The functional MR urographyintra- and inter-reading agreements as well as the agreement between the two imaging techniques were calculated. SRF was evaluated by Area Under the Curve and Rutland-Patlak methods. Drainage curves were classified as normal, borderline or accumulation patterns by both the techniques. Results: Fifty-two children were studied, 14 with bilateral involvement. A total of 104 kidney-urinary tracts were considered: 38 normal and 66 dilated. Considering Area Under the Curve and Rutland-Patlak for SRF, the intra- and inter-reader agreements of functional MR urography had excellent and good results, respectively, and the two techniques demonstrated a good concordance (r2: 67% for Area Under the Curve and 72% for Rutland-Patlak). Considering drainage curves, the inter-readers agreement for functional MR urography and the concordance between the two techniques were moderate (Cohen's k, respectively, 55.7 and 56.3%). Conclusions: According to our results, there are no significant differences between functional MR urography and DRS in measuring volumetric SRF and in the classification of drainage curves in patients with congenital anomalies of the kidney and urinary tract.

Electroclinical features of epilepsy in patients with InvDup(15).

PURPOSE: InvDup(15) syndrome is one of the most common chromosomal abnormalities associated with epilepsy. Here we review the seizure types described in InvDup(15) patients and the main electroclinical, therapeutic, and prognostic aspects of the syndrome. METHODS: A literature search of PubMed, MEDLINE, and EMBASE was performed to identify papers examining InvDup(15) syndrome and epilepsy. RESULTS: About 65% of the InvDup(15) patients described in the literature had multiple seizure types with a predominance (40.4%) of tonic-clonic seizures. Age at seizure onset was before 10 years in more than half of them. Patients suffered from a variety of EEG abnormalities, generalized spike activity being the most frequent. Brain MRI was unremarkable in the majority of patients. Treatment was with several anticonvulsant drugs used as mono- or polytherapy. Valproic acid was the most common treatment against generalized seizures and was often effective, although drug resistance was a major concern in a large number of cases. Finally, more than 30% of the children suffered from infantile spasms, and status epilepticus was described in nearly 20% of patients, occasionally resulting in death. CONCLUSION: Seizures are very common in InvDup(15) patients, who suffer from a variety of seizure types. Information about EEG and brain MRI findings, seizure treatment, and prognosis is often poor. The overall prognosis is fair. Prospective studies of larger samples are needed, to gain further insights into the natural history of InvDup(15) syndrome.