Zero-echo time MRI: an alternative method for the diagnosis of urinary stones in children.

OBJECTIVES: To evaluate the potential of zero-echo time-magnetic resonance imaging (ZTE-MRI) in the assessment of urolithiasis and compare ZTE-MRI with computed tomography (CT) in pediatric patients. MATERIALS AND METHODS: This was a single-center, prospective cross-sectional study conducted between April 2023 and December 2023. 23 patients (12 girls, 11 boys; mean age: 12.3, range 1-18) with urinary tract stones detected on non-enhanced abdominal CT were enrolled. The images were evaluated independently by two radiologists for the presence, and number of stones in the kidneys, ureters, and bladder. In the second session, two radiologists evaluated whether urinary tract stones could be detected by MRI compared to CT, and the maximum diameter of the stones was measured. The CT and MRI results were compared with the Wilcoxon test. The agreement between the results of the observers was examined using Spearman's rho correlation coefficient and the intraclass correlation coefficient. RESULTS: A total of 58 urinary tract stones were detected by CT and 39 of these were detected by MRI. Most of the stones that MRI could not detect were < 5 mm and the detection sensitivity of MRI increased in correlation with stone size (p < 0.001). There was poor intermodality agreement for stones < 5 mm, substantial agreement for stones 5-10 mm, and almost perfect agreement for stones > 10 mm. Interobserver agreement for stone detection on MRI was almost perfect for stones > 10 mm and 5-10 mm and was substantial for stones < 5 mm. CONCLUSION: ZTE-MRI is a promising modality for detecting urinary stones without radiation exposure in children. CLINICAL RELEVANCE STATEMENT: Zero-echo time-magnetic resonance imaging is a potential method for identifying urinary stones in children and other populations who are particularly sensitive to radiation. KEY POINTS: Urinary system stone disease in children is increasing and imaging is needed for managing urolithiasis. Zero-echo time-magnetic resonance imaging (ZTE-MRI) had an accuracy of 81.8% and 93.7% for stones larger than 5 mm and 10 mm, respectively. ZTE-MRI is a potential non-irradiating method for the diagnosis and management of urolithiasis.

Abdominal imaging in precocious puberty in girls: can imaging determine onset of puberty?

Precocious puberty in girls is defined by the appearance of secondary sex characteristics before the age of 8 years. Precocious puberty is either peripheral or central. In most cases, the cause of central precocious puberty is unknown. Rapidly progressive forms of central precocious puberty may benefit from puberty suppression to prevent compromised final height and psychosocial problems related to the physical changes. Idiopathic central precocious puberty in girls can be a challenging diagnosis. Clinical examination, evaluation of growth charts, bone age, and hormonal tests are part of the workup. The role of pelvic ultrasound to evaluate pubertal features of the internal genitalia in this context is controversial. In this paper, we have reviewed the literature to find the scientific bases for several proposed ultrasound parameters and cutoff values for the determination of onset of puberty in girls with suspected central precocious puberty. There are no reliable cutoffs for the measurements of uterus and ovaries for the diagnosis of central precocious puberty and there is overlap in the appearance of the organs in both prepubertal and pubertal girls. The interpretation of the findings on pelvic ultrasound must be done with caution and always in close communication with the referring clinicians.

Imaging findings of primary lung tumors in children.

PURPOSE: Pediatric lung tumors are primarily discussed in the surgical literature. However, limited research has been reported on their imaging findings, and only a few tumor types have been documented. Therefore, the aim of this article is to describe the imaging features of primary lung tumors in children. METHODS: The archives of the pediatric radiology unit were reviewed for primary lung tumors documented between 2007 and 2023. In total, 24 patients (9 girls and 15 boys; aged 5 months to 16 years) were included in the study. Their demographic characteristics, clinical presentation, and histopathologic results were obtained. All imaging studies were reviewed by two radiologists for various findings (e.g., lymphadenopathy, atelectasis, pleural effusion, calcification, multiplicity, pneumothorax, axial and lobar location, laterality, tumor margin, mediastinal shift, contrast enhancement pattern, signal intensity on T1- and T2-weighted images, and diffusion pattern), and a final decision was made by consensus. The mean tumor size was compared between the benign and malignant groups using a t-test. RESULTS: There were 15 (62.5%) benign tumors, as follows: inflammatory myofibroblastic tumor (IMT; n = 10, 41%), hemangioma (n = 2, 8%), pneumocytoma (n = 2, 8%), and mature cystic teratoma (n = 1, 4%). Moreover, there were 9 (37.5%) malignant tumors, as follows: pleuropulmonary blastoma (PPB; n = 6, 25%), adenocarcinoma (n = 2, 8%), and lymphoepithelioma-like carcinoma (LELC) (n = 1, 4%). The most frequently reported symptoms were cough, fever, dyspnea, chest pain, and recurrent infection; six patients reported no clinical symptoms. Fifteen tumors (62%) were located in the right lung. The mean tumor diameter at the time of diagnosis was 6.4 ± 3 cm (benign group: 6.7 ± 3.4 cm; malignant group: 6 ± 2.3 cm, P > 0.050). Calcification was present in 80% of the patients with IMT. At the time of diagnosis, two (8.3%) patients were found to have metastasis: one was diagnosed with adenocarcinoma and the other with LELC. Tumors were located peripherally in 18 (75%) patients. CONCLUSION: The symptoms associated with lung masses are non-specific. There is no correlation between tumor size and malignancy. The most common tumors observed in this study were IMT and PPB, respectively. IMT is highly associated with calcification. CLINICAL SIGNIFICANCE: Primary lung tumors are rarely seen in children, and they have different histopathological types. Calcification might be an important radiological clue for the diagnosis of IMT, which is the most common lung tumor in children.

The role of malnutrition on outcomes of multisystem inflammatory syndrome in children (MIS-C) due to COVID-19.

BACKGROUND: Malnutrition increases the complications and mortality in critically-ill children. We performed a retrospective analysis to define the impact of malnutrition on the outcomes of multisystem inflammatory syndrome in children (MIS-C) due to COVID-19. METHODS: Patients with MIS-C were evaluated for demographic features, anthropometric parameters, clinical findings and outcomes. Patients with z scores of body mass index (> 5 years) and weight-for-age (< 5 years) < -2 were considered malnourished. Sarcopenia was defined by total psoas muscle area (tPMA), calculated on abdominal computed tomography (CT) at the level of L3 and L4 vertebrae. The z scores <- 2 for tPMA were considered sarcopenia. The results of patients with and without malnutrition were compared. RESULTS: Twenty-seven patients were included. Forty-four percent (n=12) of patients had malnutrition. Malnutrition was classified as mild to moderate (1/3), severe (1/3) and overweight (1/3). Eighty-two % of cases had acute malnutrition. Among MIS-C symptom criteria, rash was significantly higher in children with malnutrition (p<0.05). Laboratory investigations showed higher ferritin levels in patients with malnutrition (p<0.05). The median tPMA and sarcopenia were significantly higher in patients with malnutrition when compared to patients without malnutrition (42% vs 7%, p<0.05). The oral feeding time, complication rates, and length of hospital stay were similar in both groups (p>0.05). CONCLUSION: Children with MIS-C already had mild to severe malnutrition at admission. Rash and higher ferritin levels were more common in patients with malnutrition. In addition to anthropometric parameters, sarcopenia calculated using tPMA can be used to predict malnutrition in critically-ill children.

Update on imaging recommendations in paediatric uroradiology: the European Society of Paediatric Radiology workgroup session on voiding cystourethrography.

Voiding cystourethrography (VCUG) is a fluoroscopic technique that allows the assessment of the urinary tract, including the urethra, bladder, and-if vesicoureteral reflux (VUR) is present-the ureters and the pelvicalyceal systems. The technique also allows for the assessment of bladder filling and emptying, providing information on anatomical and functional aspects. VCUG is, together with contrast-enhanced voiding urosonography (VUS), still the gold standard test to diagnose VUR and it is one of the most performed fluoroscopic examinations in pediatric radiology departments. VCUG is also considered a follow-up examination after urinary tract surgery, and one of the most sensitive techniques for studying anatomy of the lower genitourinary tract in suspected anatomical malformations. The international reflux study in 1985 published the first reflux-protocol and graded VUR into five classes; over the following years, other papers have been published on this topic. In 2008, the European Society of Paediatric Radiology (ESPR) Uroradiology Task Force published the first proposed VCUG Guidelines with internal scientific society agreement. The purpose of our work is to create a detailed overview of VCUG indications, procedural recommendations, and to provide a structured final report, with the aim of updating the 2008 VCUG paper proposed by the European Society of Paediatric Radiology (ESPR). We have also compared VCUG with contrast-enhanced VUS as an emergent alternative. As a result of this work, the ESPR Urogenital Task Force strongly recommends the use of contrast-enhanced VUS as a non-radiating imaging technique whenever indicated and possible.

Pancake kidney and jejunal atresia: An uncommon dual anomaly detected prenatally-A case report.

Pancake kidney is a renal fusion anomaly with only a few reported prenatal diagnoses. Other structural anomalies beyond the urogenital system may also be associated. This study describes a dual anomaly case detected prenatally, comprising of pancake kidney and jejunal atresia. A postnatal abdominal ultrasound confirmed both kidneys were fused in the midline at the aortic bifurcation level, along with a type 3b jejunal atresia. Based on the available limited evidence about pancake kidney, renal functions appear to remain largely preserved and unaffected as in our case according to 6 months of follow-up. However, further investigation is needed to explore any potential association with chromosomal and structural abnormalities in selected cases.

Radiomics in differential diagnosis of Wilms tumor and neuroblastoma with adrenal location in children.

OBJECTIVES: Machine learning methods can be applied successfully to various medical imaging tasks. Our aim with this study was to build a robust classifier using radiomics and clinical data for preoperative diagnosis of Wilms tumor (WT) or neuroblastoma (NB) in pediatric abdominal CT. MATERIAL AND METHODS: This is a single-center retrospective study approved by the Institutional Ethical Board. CT scans of consecutive patients diagnosed with WT or NB admitted to our hospital from January 2005 to December 2021 were evaluated. Three distinct datasets based on clinical centers and CT machines were curated. Robust, non-redundant, high variance, and relevant radiomics features were selected using data science methods. Clinically relevant variables were integrated into the final model. Dice score for similarity of tumor ROI, Cohen's kappa for interobserver agreement among observers, and AUC for model selection were used. RESULTS: A total of 147 patients, including 90 WT (mean age 34.78 SD: 22.06 months; 43 male) and 57 NB (mean age 23.77 SD:22.56 months; 31 male), were analyzed. After binarization at 24 months cut-off, there was no statistically significant difference between the two groups for age (p = .07) and gender (p = .54). CT clinic radiomics combined model achieved an F1 score of 0.94, 0.93 accuracy, and an AUC 0.96. CONCLUSION: In conclusion, the CT-based clinic-radiologic-radiomics combined model could noninvasively predict WT or NB preoperatively. Notably, that model correctly predicted two patients, which none of the radiologists could correctly predict. This model may serve as a noninvasive preoperative predictor of NB/WT differentiation in CT, which should be further validated in large prospective models. CLINICAL RELEVANCE STATEMENT: CT-based clinic-radiologic-radiomics combined model could noninvasively predict Wilms tumor or neuroblastoma preoperatively. KEY POINTS: • CT radiomics features can predict Wilms tumor or neuroblastoma from abdominal CT preoperatively. • Integrating clinic variables may further improve the performance of the model. • The performance of the combined model is equal to or greater than human readers, depending on the lesion size.

Liver magnetic resonance elastography and fat fraction in pediatric patients with cystic fibrosis versus healthy children.

BACKGROUND: Liver involvement is an important cause of morbidity and mortality in patients with cystic fibrosis (CF). While liver biopsy is the gold standard for demonstrating involvement, its invasiveness prompts a search for noninvasive alternatives. OBJECTIVE: To evaluate liver involvement in pediatric patients with CF (versus healthy controls) using magnetic resonance (MR) elastography/spectroscopy and to correlate the imaging findings with clinical/laboratory characteristics. MATERIALS AND METHODS: This was a single-center, prospective cross-sectional study conducted between April 2020 and March 2022 in patients with CF versus healthy controls. Patients with CF were divided into two subgroups: those with CF-related liver disease and those without. MR images were acquired on a 1.5-tesla machine. Kilopascal (kPa) values were derived from processing MR elastography images. MR spectroscopy was used to measure liver fat fraction, as an indication of hepatosteatosis. Groups were compared using either the Student's t test or the Mann‒Whitney U test. The chi-square test or Fisher's exact test were used to compare qualitative variables. RESULTS: Fifty-one patients with CF (12 ± 3.3 years, 32 boys) and 24 healthy volunteers (11.1 ± 2.4 years, 15 boys) were included in the study. Median liver stiffness (P=0.003) and fat fraction (P=0.03) were higher in the CF patients than in the controls. Median liver stiffness values were higher in CF patients with CF-related liver disease than in those without CF-related liver disease (P=0.002). Liver stiffness values of CF patients with high alanine aminotransferase (ALT), high gamma-glutamyl transferase, and thrombocytopenia were found to be higher than those without (P=0.004, P<0.001, P<0.001, respectively). Only the high ALT group showed a high fat fraction (P=0.002). CONCLUSIONS: Patients with CF had higher liver stiffness than the control group, and patients with CF-related liver disease had higher liver stiffness than both the CF patients without CF-related liver disease and the control group. Patients with CF had a higher fat fraction than the control group. Noninvasive assessment of liver involvement using MR elastography/spectroscopy can support the diagnosis of CF-related liver disease and the follow-up of patients with CF.

Imaging Features of Pediatric Sarcoidosis.

Sarcoidosis is a granulomatous inflammatory disease of uncertain cause. It occurs most commonly in young and middle-aged adults and less frequently in children; therefore, few data on pediatric sarcoidosis exist in the literature. The diagnosis and management of sarcoidosis remain challenging because of diverse and often nonspecific clinical and imaging findings. In addition, the clinical picture varies widely by age. Prepubertal and adolescent patients often present with adult-like pulmonary disease; however, early-onset sarcoidosis is typically characterized by the triad of arthritis, uveitis, and skin rash. Sarcoidosis is mostly a diagnosis of exclusion made by demonstrating noncaseating granulomas at histopathologic examination in patients with compatible clinical and radiologic findings. Although sarcoidosis often affects the lungs and thoracic lymph nodes, it can involve almost any organ in the body. The most common radiologic manifestation is pulmonary involvement, characterized by mediastinal and bilateral symmetric hilar lymphadenopathies with perilymphatic micronodules. Abdominal involvement is also common in children and often manifests as hepatomegaly, splenomegaly, and abdominal lymph node enlargement. Although neurosarcoidosis and cardiac sarcoidosis are rare, imaging is essential to the diagnosis of central nervous system and cardiac involvement because of the risky biopsy procedure and its low diagnostic yield due to focal involvement. Being familiar with the spectrum of imaging findings of sarcoidosis may aid in appropriate diagnosis and management. ©RSNA, 2023 Test Your Knowledge questions are available in the supplemental material.