Magnetic resonance imaging (MRI) is playing an increasing role in pediatric abdominal imaging, especially in the evaluation of diffuse parenchymal disease where other imaging modalities might be less ...sensitive. While quantitative imaging is slowly being incorporated into clinical imaging, qualitative assessment of visceral signal intensity should be part of the routine clinical workflow of all radiologists. Based on their T1 and T2 weighting, the liver, spleen, kidneys and pancreas have characteristic signal intensity patterns with respect to one another and to skeletal muscle. It is important to recognize normal signal intensity patterns of viscera and their evolution with patient age to be able to identify age-related variations and accurately identify diffuse parenchymal disease. Knowledge of normal signal intensity patterns can also help identify ectopic locations of normal tissue such as splenic rests and splenosis. In this review, we discuss normal signal intensity patterns of upper abdominal viscera and their variations on commonly used sequences in pediatric abdominal MRI. We also review normal variations in the perinatal period. Knowledge of these patterns can help pediatric radiologists become more astute in their interpretation of diffuse parenchymal disease in the abdomen.
Whole-body MR imaging is being increasingly used in children to evaluate the extent of various oncologic and non-oncologic entities. The lack of exposure to ionizing radiation, excellent soft-tissue ...contrast (even without the use of contrast agents), and functional imaging capabilities make it especially suitable for screening and surveillance in the pediatric population. Technical developments such as moving table platforms, multi-channel/multi-element surface coils, and parallel imaging allow imaging of the entire body with multiple sequences in a reasonable 30- to 40-min time frame, which has facilitated its acceptance in routine clinical practice. The initial investigations in whole-body MR imaging were primarily focused on oncologic applications such as tumor screening and staging. The exquisite sensitivity of fluid-sensitive MR sequences to many different types of pathology has led to new applications of whole-body MR imaging in evaluation of multifocal rheumatologic conditions. Availability of blood pool contrast agents has allowed whole-body MR angiographic imaging of vascular malformations, vasculitides and vasculopathies. Whole-body MRI is being applied for delineating the extent and distribution of systemic and multifocal diseases, establishing diagnoses, assessing treatment response, and surveillance imaging. This article reviews the technique and clinical applications of whole-body MR imaging in children.
Chronic recurrent multifocal osteomyelitis (CRMO) is an autoinflammatory disorder of children and young adults that is characterized by nonbacterial osteomyelitis. Patients typically present with ...multifocal bone pain secondary to sterile osseous inflammation, and the disease has a relapsing and remitting course. The cause of CRMO remains unclear, although the results of several studies have suggested a genetic component. The typical imaging findings of CRMO include lytic and sclerotic lesions in the metaphyses of long bones and the medial clavicles. Other common sites of disease are the vertebral bodies, pelvis, ribs, and mandible. CRMO is often bilateral and multifocal at presentation. Owing to the lack of a diagnostic test, CRMO remains a diagnosis of exclusion. Although generally a self-limiting disease, CRMO can have a prolonged course and result in significant morbidity. Radiologists can be the first to suggest this diagnosis given its characteristic radiographic appearance and distribution of disease. Radiologists should be familiar with the typical imaging findings of CRMO to prevent unnecessary multiple biopsies and long-term antibiotic treatment in children with CRMO.
Appropriate imaging is imperative in evaluating children with a primary hepatic malignancy such as hepatoblastoma or hepatocellular carcinoma. For use in the adult patient population, the American ...College of Radiology created the Liver Imaging Reporting and Data System (LI-RADS) to provide consistent terminology and to improve imaging interpretation. At present, no similar consensus exists to guide imaging and interpretation of pediatric patients at risk for developing a liver neoplasm or how best to evaluate a pediatric patient with a known liver neoplasm. Therefore, a new Pediatric Working Group within American College of Radiology LI-RADS was created to provide consensus for imaging recommendations and interpretation of pediatric liver neoplasms. The article was drafted based on the most up-to-date existing information as interpreted by imaging experts comprising the Pediatric LI-RADS Working Group. Guidance is provided regarding appropriate imaging modalities and protocols, as well as imaging interpretation and reporting, with the goals to improve imaging quality, to decrease image interpretation errors, to enhance communication with referrers, and to advance patient care. An expanded version of this document that includes broader background information on pediatric hepatocellular carcinoma and rationale for recommendations can be found in Appendix E1 (online).
Background The National Wilms Tumor Study (NWTS) approach to treating stage III favorable-histology Wilms tumor (FHWT) is Regimen DD4A (vincristine, dactinomycin, and doxorubicin) and radiation ...therapy. Further risk stratification is required to improve outcomes and reduce late effects. We evaluated clinical and biologic variables for patients with stage III FHWT without combined loss of heterozygosity (LOH) at chromosomes 1p and 16q treated in the Children's Oncology Group protocol AREN0532. Methods From October 2006 to August 2013, 588 prospectively treated, centrally reviewed patients with stage III FHWT were treated with Regimen DD4A and radiation therapy. Tumor LOH at 1p and 16q was determined by microsatellite analysis. Ineligible patients (n = 5) and those with combined LOH 1p/16q (n = 40) were excluded. Results A total of 535 patients with stage III disease were studied. Median follow-up was 5.2 years (range, 0.2 to 9.5). Four-year event-free survival (EFS) and overall survival estimates were 88% (95% CI, 85% to 91%) and 97% (95% CI, 95% to 99%), respectively. A total of 58 of 66 relapses occurred in the first 2 years, predominantly pulmonary (n = 36). Eighteen patients died, 14 secondary to disease. A better EFS was associated with negative lymph node status ( P < .01) and absence of LOH 1p or 16q ( P < .01), but not with gross residual disease or peritoneal implants. In contrast, the 4-year EFS was only 74% in patients with combined positive lymph node status and LOH 1p or 16q. A total of 123 patients (23%) had delayed nephrectomy. Submitted delayed nephrectomy histology showed anaplasia (n = 8; excluded from survival analysis); low risk/completely necrotic (n = 7; zero relapses), intermediate risk (n = 63; six relapses), and high-risk/blastemal type (n=7; five relapses). Conclusion Most patients with stage III FHWT had good EFS/overall survival with DD4A and radiation therapy. Combined lymph node and LOH status was highly predictive of EFS and should be considered as a potential prognostic marker for future trials.
Secretory carcinoma (SC) is a rare salivary gland tumor and has been recently included in the fourth edition of the World Health Organization classification of head and neck tumors. To understand the ...histopathologic findings and clinical behavior of mammary analogue secretory carcinoma (MASC) of the submandibular gland in a 23 year old female. MASC is an intriguing and rare malignant salivary gland tumor first described in 2010. It shares histologic, immunohistochemical and genetic features with secretory carcinoma of the breast. The clinical behavior of MASC ranges from slowly growing tumors to aggressive tumors that can cause widespread metastasis. Many cases of MASC were discovered in archived cases previously classified as pleomorphic adenoma, acinic cell carcinoma, mucoepidermoid carcinoma, and adenocarcinoma. They are only a few reported in submandibular gland. MASC is a newly recognized variant of salivary gland malignancy. Further research is needed to better delineate its overall prevalence and to define an appropriate treatment algorithm for this new clinical entity.
AREN0321 evaluated the activity of vincristine and irinotecan (VI) in patients with newly diagnosed diffuse anaplastic Wilms tumor (DAWT) and whether a regimen containing carboplatin (regimen UH1) in ...addition to regimen I agents used in the National Wilms Tumor Study 5 (NWTS-5; vincristine, doxorubicin, cyclophosphamide, and etoposide plus radiotherapy) would improve patient outcomes.
Patients with stage II to IV DAWT without measurable disease received regimen UH1. Patients with stage IV measurable disease were eligible to receive VI (vincristine, 1.5 mg/m
per day intravenously on days 1 and 8; irinotecan, 20 mg/m
per day intravenously on days 1-5 and 8-12 of a 21-day cycle) in an upfront window; those with complete (CR) or partial response (PR) had VI incorporated into regimen UH1 (regimen UH2). The study was designed to detect improvement in outcomes of patients with stage II to IV DAWT compared with historical controls treated with regimen I.
Sixty-six eligible patients were enrolled. Of 14 patients with stage IV measurable disease who received VI, 11 (79%) achieved CR (n = 1) or PR (n = 10) after 2 cycles. Doses of doxorubicin, cyclophosphamide, and etoposide were reduced midstudy because of nonhematologic toxicity. Four patients (6%) died as a result of toxicity. Four-year event-free survival, relapse-free survival, and overall survival rates were 67.7% (95% CI, 55.9% to 79.4%), 72.9% (95% CI, 61.5% to 84.4%), and 73.7% (95% CI, 62.7% to 84.8%), respectively, compared with 57.5% (95% CI, 47.6% to 67.4%;
= .26), 57.5% (95% CI, 47.6% to 67.4%;
= .048), and 59.2% (95% CI, 49.4% to 69.0%;
= .08), respectively, in NWTS-5.
VI produced a high response rate in patients with metastatic DAWT. AREN0321 treatment seemed to improve outcomes for patients with stage II to IV DAWT compared with NWTS-5, but with increased toxicity. The UH2 regimen warrants further investigation with modifications to reduce toxicity.
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