Indications and results of diagnostic biopsy in pediatric renal tumors: A retrospective analysis of 317 patients with critical review of SIOP guidelines.

OBJECTIVES: According to the Renal Tumor Study Group (RTSG) of the International Society of Paediatric Oncology (SIOP), diagnostic biopsy of renal tumors prior to neoadjuvant chemotherapy is not mandatory unless the presentation is atypical for a Wilms tumor (WT). This study addresses the relevance of this strategy as well as the accuracy and safety of image-guided needle biopsy. METHODS: Clinical, radiological, and pathological data from 317 children (141 males/176 females, mean age: 4 years, range, 0-17.6) consecutively treated in one SIOP-affiliated institution were retrospectively analyzed. RESULTS: Presumptive chemotherapy for WT was decided for 182 patients (57% of the cohort), 24 (8%) were operated upfront, and 111 (35%) were biopsied at diagnosis. A non-WT was confirmed after surgery in 5/182 (3%), 11/24 (46%), and 28/111 (25%), respectively. Age at diagnosis was the most commonly (46%) used criterion to go for biopsy but a nine-year threshold should be retrospectively considered more relevant. Tumor volumes of clear cell sarcoma of the kidney and WT were significantly higher than those of other tumors (P = 0.002). The agreement between core-needle biopsy (CNB) and final histology was 99%. No significant morbidity was associated with CNB. CONCLUSION: The use of SIOP criteria to identify patients eligible for presumptive WT neoadjuvant chemotherapy or upfront surgery avoided biopsy in 65% of children and led to a 97% rate of appropriate preoperative chemotherapy. Image-guided CNB is a safe and accurate diagnostic procedure. The relevance of SIOP biopsy criteria might be improved by using an older age threshold (9 years instead of 6 years) and by adding initial tumor volume.

Dose reduction with adaptive statistical iterative reconstruction for paediatric CT: phantom study and clinical experience on chest and abdomen CT.

OBJECTIVES: To assess the benefit and limits of iterative reconstruction of paediatric chest and abdominal computed tomography (CT). METHODS: The study compared adaptive statistical iterative reconstruction (ASIR) with filtered back projection (FBP) on 64-channel MDCT. A phantom study was first performed using variable tube potential, tube current and ASIR settings. The assessed image quality indices were the signal-to-noise ratio (SNR), the noise power spectrum, low contrast detectability (LCD) and spatial resolution. A clinical retrospective study of 26 children (M:F = 14/12, mean age: 4 years, range: 1-9 years) was secondarily performed allowing comparison of 18 chest and 14 abdominal CT pairs, one with a routine CT dose and FBP reconstruction, and the other with 30 % lower dose and 40 % ASIR reconstruction. Two radiologists independently compared the images for overall image quality, noise, sharpness and artefacts, and measured image noise. RESULTS: The phantom study demonstrated a significant increase in SNR without impairment of the LCD or spatial resolution, except for tube current values below 30-50 mA. On clinical images, no significant difference was observed between FBP and reduced dose ASIR images. CONCLUSION: Iterative reconstruction allows at least 30 % dose reduction in paediatric chest and abdominal CT, without impairment of image quality. KEY POINTS: • Iterative reconstruction helps lower radiation exposure levels in children undergoing CT. • Adaptive statistical iterative reconstruction (ASIR) significantly increases SNR without impairing spatial resolution. • For abdomen and chest CT, ASIR allows at least a 30 % dose reduction.

[Role of French hospital claims databases from care units in epidemiological studies: the example of the "Cohorte Enfant Scanner" study]. / Utilisation des données du programme de médicalisation des systèmes d'information (PMSI) dans les études épidémiologiques : application à la Cohorte Enfant Scanner.

BACKGROUND: The "Cohorte Enfant Scanner", a study designed to investigate the risk of radiation-induced cancer after childhood exposure to CT (computed tomography) examinations, used clinical information contained in the "programme de médicalisation des systèmes d'information" (PMSI) database, the French hospital activities national program based upon diagnosis related groups (DRG). However, the quality and adequacy of the data for the specific needs of the study should be verified. The aim of our work was to estimate the percentage of the cohort's children identified in the PMSI database and to develop an algorithm to individualize the children with a cancer or a disease at risk of cancer from medical diagnoses provided by the DRGs database. METHODS: Of the 1519 children from the "Cohorte Enfant Scanner", who had had a CT scan in the radiology department of a university hospital in 2002, a cross linkage was performed with the DRGs database. All hospitalizations over the period 2002-2009 were taken into account. An algorithm was constructed for the items "cancer" and "disease at risk for cancer" on a sample of 150 children. The algorithm was then tested on the entire population. RESULTS: Overall, 74% of our population was identified in the DRGs database. The algorithm individualized cancer diagnoses with 91% sensitivity (95% confidence interval [95%CI]: 86%; 97%) and 98% specificity (95%CI: 97%; 99%) and 86% positive predictive value (95%CI: 80%; 93%). For the diagnosis of disease at risk for cancer, the sensitivity, specificity and positive predictive value were respectively 91% (95%CI: 84%; 98%), 94% (95%CI: 92%; 95%) and 52% (95%CI: 43%; 61%). CONCLUSION: The DRG database identified with excellent sensitivity and specificity children with diagnoses of cancer or disease at risk for cancer. Hence, potential confounding factors related to the disease of the child can be taken into account for analyses performed with the cohort.

Imaging Features with Histopathologic Correlation of CNS High-Grade Neuroepithelial Tumors with a BCOR Internal Tandem Duplication.

BACKGROUND AND PURPOSE: A new brain tumor entity occurring in early childhood characterized by a somatic BCL6 corepressor gene internal tandem duplication was recently described. The aim of this study was to describe the radiologic pattern of these tumors and correlate this pattern with histopathologic findings. MATERIALS AND METHODS: This retrospective, noninterventional study included 10 children diagnosed with a CNS tumor, either by ribonucleic acid-sequencing analysis or deoxyribonucleic acid methylation analysis. Clinical, radiologic, and histopathologic data were collected. A neuropathologist reviewed 9 tumor samples. Preoperative images were analyzed in consensus by 7 pediatric radiologists. RESULTS: All tumors were relatively large (range, 4.7-9.2 cm) intra-axial peripheral masses with well-defined borders and no peritumoral edema. All tumors showed mild and heterogeneous enhancement and marked restriction on DWI of the solid portions. Perfusion imaging showed a relatively lower CBF in the tumor than in the adjacent normal parenchyma. Nine of 10 tumors showed areas of necrosis, with the presence of hemorrhage in 8/10 and calcifications in 4/7. Large intratumoral macroscopic veins were observed in 9/10 patients. No intracranial or spinal leptomeningeal dissemination was noted at diagnosis. CONCLUSIONS: CNS tumors with a BCL6 corepressor gene internal tandem duplication present as large intra-axial peripheral masses with well-defined borders, no edema, restricted diffusion, weak contrast enhancement, frequent central necrosis, hemorrhage and calcifications, intratumoral veins, and no leptomeningeal dissemination at the time of diagnosis. Knowledge of these imaging characteristics may aid in histologic, genomic, and molecular profiling of brain tumors in young children.

Soft tissue sarcoma in children, adolescents and young adults: Outcomes according to compliance with international initial care guidelines.

BACKGROUND: Outcomes for adults with soft tissue sarcoma are better when managed at referral centers. Care guidelines advise for 5 main criteria: 1-Imaging before biopsy; 2-Tumor biopsy before surgery; 3-Multidiscipinary team discussion (MTD) before biopsy; 4-Biopsy in "expert centers"; 5-Somatic molecular biology feasible. The aim is to describe and assess the prognostic impact of initial management of STS according to the type of referring centers and the number of optimal criteria. METHODS: Monocentric retrospective analysis of the management of 127 youths (0-25 years) with localized STS treated from 2006 to 2015. RESULTS: Median age at diagnosis was 9.6 years (range: 025). Overall, only 41% patients had 5/5, 28% 3-4, 31% ≤2. No adequate imaging was performed before surgery/biopsy for 18% patients, no biopsy before treatment for 29%. Patients referred by "expert centers" had higher compliance to guidelines (P = 0.025). Upfront surgery was performed in 59/127 patients. Immediate re-operation was inversely related to the number of criteria (0% when 5 criteria vs. 14% for 3-4, 46% if ≤ 2; P < 0.001). For malignant tumors, outcome was better when 5 criteria were reached: 5 year EFS 90.8% (81.4-100.0%) vs. 71.6 for (60.4-84.9%; ≤4 criteria; p = 0.033), OS 93.6% (85.5-100%) vs. 79.5% (68.9-91.8%; p = 0.11), and LRFFS 90.6% (81.0-100.0) vs. 73.1% (62.0-86.3%; p = 0.047). CONCLUSION: Less than half of the youths with STS are initially managed according to international guidelines, highlighting the need for better information about optimal management. These results plead for immediate management in reference centers to reduce initial burden of therapy.

The relevance of image quality indices for dose optimization in abdominal multi-detector row CT in children: experimental assessment with pediatric phantoms.

This study assessed and compared various image quality indices in order to manage the dose of pediatric abdominal MDCT protocols and to provide guidance on dose reduction. PMMA phantoms representing average body diameters at birth, 1 year, 5 years, 10 years and 15 years of age were scanned in a four-channel MDCT with a standard pediatric abdominal CT protocol. Image noise (SD, standard deviation of CT number), noise derivative (ND, derivative of the function of noise with respect to dose) and contrast-to-noise ratio (CNR) were measured. The 'relative' low-contrast detectability (rLCD) was introduced as a new quantity to adjust LCD to the various phantom diameters on the basis of the LCD(1%) assessed in a Catphan phantom and a constant central absorbed dose. The required variations of CTDIvol(16) with respect to phantom size were analyzed in order to maintain each image quality index constant. The use of a fixed SD or CNR level leads to major dose ratios between extreme patient sizes (factor 22.7 to 44 for SD, 31.7 to 51.5 for CNR(2.8%)), whereas fixed ND and rLCD result in acceptable dose ratios ranging between factors of 2.9 and 3.9 between extreme phantom diameters. For a 5-9 mm rLCD1(%), adjusted ND values range between -0.84 and -0.11 HU mGy(-1). Our data provide guidance on dose reduction on the basis of patient dimensions and the required rLCD (e.g., to get a constant 7 mm rLCD(1%) for abdominal diameters of 10, 13, 16, 20 and 25 cm, tube current-time product should be adjusted in order to obtain CTDIvol(16) values of 6.2, 7.2, 8.8, 11.6 and 17.7 mGy, respectively).

[CT exposure from pediatric MDCT: results from the 2007-2008 SFIPP/ISRN survey]. / Niveaux d'exposition en tomodensitométrie multicoupes pédiatrique: résultats de l'enquête dosimétrique SFIPP/IRSN 2007-2008.

PURPOSE: To evaluate current exposure levels from pediatric MDCT examinations in order to issue recommendations for the routine clinical practice that may be used for establishing future diagnostic reference levels (DRL). Materials and methods. A survey was conducted at hospital sites affiliated with the SFIPP (Société Francophone d'Imagerie Pédiatrique et Prénatale). Tube potential and volume computed tomography dose index (CTDI) vol. values were obtained for three age groups (1, 5 and 10 years) for typical scanning indications of eight anatomical regions. RESULTS: Twenty of 29 sites provided us with a copy of their protocols. All ages groups combined, 97% of protocols used a tension level < or =120 kVp. For age groups 1, 5 and 10 years respectively, the 75th percentiles of dose distributions were: 31, 39.5 and 49.5 mGy for the "head" protocol; 24, 22 and 24 mGy for "head and neck"; 11, 11, and 11 mGy for "paranasal sinuses"; 46, 71 and 87 mGy for "petrous bone"; 3, 3.5 and 5.5 mGy for "chest"; 2, 3 and 4 mGy for "low dose lung"; 4, 4.5 and 7 mGy for "abdomen-pelvis"; 7, 11 and 12 mGy for "bone". The inter-center discrepancy for doses were still high. CONCLUSION: This study provided an evaluation of current practices in reference centers for pediatric imaging and allowed readjustment of MDCT dose recommendations. It could help in the development of DRLS for pediatric MDCT.

[Pseudotumoral soft tissue masses in children and adolescents]. / Masses des tissus mous d'allure tumorale de l'enfant et de l'adolescent.

INTRODUCTION: Pseudotumoral soft tissue masses in children and adolescents are a frequent reason for consultation and a diagnostic dilemma. Soft tissue malignancies are relatively uncommon, unlike the large number of benign lesions that may be seen in the superficial tissue and that can be diagnosed with clinical characteristics. MATERIALS AND METHODS: This retrospective study concerns 161 children and adolescents less than 20 years old, referred for a soft tissue mass between 2007 and 2011. It describes their epidemiology, clinical characteristics, and course of care to validate a diagnostic strategy for such masses. RESULTS: Final diagnoses were malignant tumors (44%), benign tumors (32%), and pseudotumoral lesions (24%). Clinical features were similar between these three groups except for age and tumor location, with more benign thoracic masses in younger children. Clinical and radiological association led to an accurate diagnosis for 50% of benign masses and with cytological analysis contribution in 79% of benign tumors and 86% of pseudotumoral lesions. Malignant tumors were suspected in only 39% of cases with radiological exams and in 89% after fine-needle aspiration, an essential additional diagnostic tool. Final diagnoses were formally established through simple standard clinical and radiological evaluation in 19 patients (11.8%; benign tumors, seven patients; malformations, eight patients; post-traumatic lesions, two patients; infection and inflammation, one patient each); ultrasound exam in five patients (3.1%; hemangioendotheliomas, two patients, fascial dehiscence, hemangioma, and vascular malformation, one patient each); MRI in four patients (2.5%; three vascular malformations and one lipoma); CT in two cases (1.2%; vascular malformation and myositis ossificans), and radiological examinations associated with cell aspiration in 15 cases (9.3%; ten benign tumors and five malignant tumors). CONCLUSIONS: A multidisciplinary approach should be requested from oncological, radiological, and pathologic experts to optimize soft tissue mass management as soon as initial investigations start. The authors advise a diagnostic strategy for children with pseudotumoral soft tissue masses.

Sonographic, CT, and MR imaging findings in diffuse infiltrative retinoblastoma: report of two cases with histologic comparison.

SUMMARY: Diffuse infiltrating retinoblastoma is a rare form of retinoblastoma. We report two cases of this disease in which sonographic, CT, and MR imaging findings were compared with histologic studies obtained after enucleation. Although nonspecific, MR imaging provides valuable morphologic data for the diagnosis of diffuse infiltrating retinoblastoma and may help in decisions regarding enucleation.

[Diagnostic radiation exposure in children and cancer risk: current knowledge and perspectives]. / Expositions radiologiques à visée diagnostique pendant l'enfance et risque de cancer : bilan des connaissances et perspectives.

The question of the risk of cancer associated with postnatal diagnostic medical exposure involving ionizing radiation in childhood is particularly relevant at the moment given the growing use of diagnostic examinations, especially computed tomography scans, in children. Compared to adults, pediatric patients are more sensitive to radiation and have more years of life expectancy and therefore more years at risk of cancer occurrence as compared to adults. This paper provides a description of diagnostic x-ray exposure in children in France and summarizes epidemiologic studies on subsequent risk of cancer. Overall, this review, based on 12 case-control studies and 6 cohort studies, shows no significant association between exposure to medical diagnostic radiation exposure and childhood cancer risk. The methodological limitations of these studies are discussed. As the expected cancer risks are low, epidemiological studies require very large sample sizes and long periods of follow-up in addition to a good dosimetry assessment to enable quantitative risk estimation. New cohort studies of young patients who underwent CT scans are currently underway within the European EPI-CT project. In the meantime, continued efforts to reduce doses and the number of radiological examinations in children are needed, including adhering to the "as long as reasonably achievable" (Alara) principle.

Radiation exposure from CT in early childhood: a French large-scale multicentre study.

OBJECTIVES: The increasing use of CT scans in the paediatric population raises the question of a possible health impact of ionising radiation exposure associated with CT scans. The aim of this study was to describe the pattern of CT use in early childhood. METHODS: In 14 major French paediatric radiology departments, children undergoing at least 1 CT scan before age 5, between 2000 and 2006, were included. For each examination, absorbed organ doses were calculated. RESULTS: 43% of the 27 362 children in the cohort were aged less than 1 year during their first exposure, with 9% being aged less than 1 month. The mean number of examinations per child was 1.6 (range 1-43). The examinations included: head in 63% of the cases, chest in 21%, abdomen and pelvis in 8% and others in 8%. Brain and eye lenses received the highest cumulative doses from head examinations, with mean organ dose values of 22 mGy (maximum 1107 mGy) and 26 mGy (maximum 1392 mGy), respectively. The mean cumulative effective dose was 3.2 mSv (range 0.1-189 mSv). CONCLUSION: CT scan exposure in childhood is responsible for relatively high doses to radiosensitive organs. The rather large dose range according to the protocols used requires their optimisation. The cohort follow-up will study the risk of long-term radiation-induced cancer.