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.

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.

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.

Focal fatty sparing areas of the pediatric steatotic liver: pseudolesions on hepatobiliary phase magnetic resonance images.

PURPOSE: Focal fatty sparing in liver can be detected as hyperintense pseudolesions on hepatobiliary phase magnetic resonance imaging (MRI). Distinguishing these pseudolesions from liver lesions may make diagnosis challenging. The aim of this study was to evaluate the imaging features of fatty sparing areas on liver MRI in pediatric patients who have been administered gadoxetate disodium. METHODS: A total of 63 patients between January 2018 and June 2023 underwent gadoxetate disodium-enhanced liver MRI, and 9 (14%) patients with a focal fatty sparing were included in the study. The fat spared areas were evaluated qualitatively and quantitatively including signal intensity measurements and fat fraction calculations. RESULTS: The liver MRI examinations of 9 patients (5 boys, 4 girls; aged 8-18 years, median age: 14.4) using gadoxetate disodium were evaluated. Based on in-phase and opposed-phase sequences, 13 areas of focal fatty sparing were identified. The mean fat fraction of the liver and fat spared areas were 26.2% (range, 15-47) and 9% (range, 2-17), respectively. All fat spared areas were hyperintense in the hepatobiliary phase images. The mean relative enhancement ratios of the liver and fat spared areas were 0.78 (range, 0.35-1.6) and 1.11 (range, 0.45-1.9), respectively. CONCLUSION: Focal fatty sparing in liver in children was observed as hyperintense on hepatobiliary phase MRI, and it should not be identified as a focal liver lesion.

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.

Many faces of torsion in pediatric female pelvis.

Pediatric patients of various ages, from infancy through adolescence, can have ovarian torsion. Torsion may not only be confined to the ovaries but may also involve the isolated cyst, tube, and even the uterus. In this pictorial review, we review the spectrum of torsion in pediatric (from infants to adolescents) female pelvis, emphasizing imaging methods.