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.

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.

Childhood CT scans and cancer risk: impact of predisposing factors for cancer on the risk estimates.

To investigate the role of cancer predisposing factors (PFs) on the associations between paediatric computed tomography (CT) scan exposures and subsequent risk of central nervous system (CNS) tumours and leukaemia. A cohort of children who underwent a CT scan in 2000-2010 in 23 French radiology departments was linked with the national childhood cancers registry and national vital status registry; information on PFs was retrieved through hospital discharge databases. In children without PF, hazard ratios of 1.07 (95% CI 0.99-1.10) for CNS tumours (15 cases) and 1.16 (95% CI 0.77-1.27) for leukaemia (12 cases) were estimated for each 10 mGy increment in CT x-rays organ doses. These estimates were similar to those obtained in the whole cohort. In children with PFs, no positive dose-risk association was observed, possibly related to earlier non-cancer mortality in this group. Our results suggest a modifying effect of PFs on CT-related cancer risks, but need to be confirmed by longer follow-up and other studies.

[Retinoblastoma update]. / Actualités du rétinoblastome.

Retinoblastoma is the most common intraocular malignancy of infancy with an incidence of 1/15,000 births. Sixty percent of retinoblastomas are unilateral, with a median age at diagnosis of 2 years, and in most cases they are not hereditary. Retinoblastoma is bilateral in 40% of cases, with an earlier median age at diagnosis of 1 year. All bilateral and multifocal unilateral forms are hereditary and are part of a genetic cancer predisposition syndrome. All children with a bilateral or familial form, and 10-15% of children with a unilateral form, constitutionally carry an RB1 gene mutation. The two most frequent symptoms at diagnosis are leukocoria and strabismus. Diagnosis is made by fundoscopy, with ultrasound and magnetic resonance imaging (MRI) contributing both to diagnosis and assessment of the extension of the disease. Treatment of patients with retinoblastoma must take into account the various aspects of the disease (unilateral/bilateral, size, location), the risks for vision, and the possible hereditary nature of the disease. The main prognostic aspects are still early detection and adapted coverage by a multidisciplinary, highly specialized team. Enucleation is still often necessary in unilateral disease; the decision for adjuvant treatment is made according to the histological risk factors. The most important recent therapeutic advances concern conservative treatment, which is proposed for at least one of the two eyes in most bilateral cases: laser alone or in combination with chemotherapy, cryotherapy, or brachytherapy. Recently, the development of new conservative techniques of treatment, such as intra-arterial selective chemotherapy perfusion and intravitreal injections, aims at preserving visual function in these children and decreasing the number of enucleations and the need for external beam radiotherapy. The vital prognosis related to retinoblastoma is now excellent in industrialized countries, but long-term survival is still related to the development of secondary tumors, mainly secondary sarcoma. Retinoblastoma requires multidisciplinary care as well as a long-term specialized follow-up. Early counseling of patients and their family concerning the risk of transmission of the disease and the risk of development of secondary tumors is necessary.

Treatment of retinoblastoma: The Institut Curie experience on a series of 730 patients (1995 to 2009).

INTRODUCTION: To describe the results of retinoblastoma treatment from 1995-2009 in a single institution. MATERIAL AND METHODS: Retrospective review of the charts of patients treated for retinoblastoma. Clinical characteristics at diagnosis, treatments and outcomes in terms of survival and ocular preservation are described. RESULTS: During the study period 826 children were referred for retinoblastoma and 730 were managed in our institution. Four hundred and eleven children presented with unilateral retinoblastoma and 319 with bilateral retinoblastoma. Median follow-up is of 93 months. Global survival is 98.5% of children, 10 children presented with second tumors, 11 children died (6 of tumor-related causes). Of the 411 children with unilateral retinoblastoma enucleation was needed at diagnosis for 324 (78.8%). Conservative treatments were attempted for 87 patients (21.2%) and ocular preservation obtained for 65 patients (74% of eyes). Three hundred and nineteen patients presented with bilateral retinoblastoma. Three hundred and ten could be treated conservatively for at least one eye. Initial intravenous chemotherapy was necessary for 75% of them. Ocular preservation without external beam radiation was possible for 221 patients (70%). The use of EBR decreased significantly after 2004 (9.1% of eyes vs 25.1%: P<0.001). DISCUSSION: Management and treatment of retinoblastoma are complex, adapted to the extent of the disease. Survival is good. Enucleation is still required for extensive ocular disease, especially for unilateral patients. Intravenous chemotherapy allows good tumor control and eye preservation and decrease the need of EBR. CONCLUSIONS: Retinoblastoma treatment with intravenous chemotherapy and ocular adjuvant therapies is very effective on the local tumor control and eye preservation.

[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.

Are the studies on cancer risk from CT scans biased by indication? Elements of answer from a large-scale cohort study in France.

BACKGROUND: Recent epidemiological results suggested an increase of cancer risk after receiving computed tomography (CT) scans in childhood or adolescence. Their interpretation is questioned due to the lack of information about the reasons for examination. Our objective was to estimate the cancer risk related to childhood CT scans, and examine how cancer-predisposing factors (PFs) affect assessment of the radiation-related risk. METHODS: The cohort included 67,274 children who had a first scan before the age of 10 years from 2000 to 2010 in 23 French departments. Cumulative X-rays doses were estimated from radiology protocols. Cancer incidence was retrieved through the national registry of childhood cancers; PF from discharge diagnoses. RESULTS: During a mean follow-up of 4 years, 27 cases of tumours of the central nervous system, 25 of leukaemia and 21 of lymphoma were diagnosed; 32% of them among children with PF. Specific patterns of CT exposures were observed according to PFs. Adjustment for PF reduced the excess risk estimates related to cumulative doses from CT scans. No significant excess risk was observed in relation to CT exposures. CONCLUSIONS: This study suggests that the indication for examinations, whether suspected cancer or PF management, should be considered to avoid overestimation of the cancer risks associated with CT scans.

Malformations, genetic abnormalities, and Wilms tumor.

BACKGROUND: Wilms Tumor (WT) can occur in association with tumor predisposition syndromes and/or with clinical malformations. These associations have not been fully characterized at a clinical and molecular genetic level. This study aims to describe clinical malformations, genetic abnormalities, and tumor predisposition syndromes in patients with WT and to propose guidelines regarding indications for clinical and molecular genetic explorations. PROCEDURE: This retrospective study analyzed clinical abnormalities and predisposition syndromes among 295 patients treated for WT between 1986 and 2009 in a single pediatric oncological center. RESULTS: Clinically identified malformations and predisposition syndromes were observed in 52/295 patients (17.6%). Genetically proven tumor predisposition syndromes (n = 14) frequently observed were syndromes associated with alterations of the chromosome WT1 region such as WAGR (n = 6) and Denys-Drash syndromes (n = 3), syndromes associated with alterations of the WT2 region (Beckwith-Wiedeman syndrome, n = 3), and Fanconi anemia (n = 2). Hemihypertrophy and genito-urinary malformations (n = 12 and n = 16, respectively) were the most frequently identified malformations. Other different syndromes or malformations (n = 10) were less frequent. Median age of WT diagnosis was significantly earlier for children with malformations than those without (27 months vs. 37 months, P = 0.0009). There was no significant difference in terms of 5-year EFS and OS between WT patients without or with malformations. CONCLUSIONS: The frequency of malformations observed in patients with WT underline the need of genetic counseling and molecular genetic explorations for a better follow-up of these patients, with a frequently good outcome. A decisional tree, based on clinical observations of patients with WT, is proposed to guide clinicians for further molecular genetic explorations.

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.

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.

[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.

[Typical patient radiation doses in diagnostic imaging]. / Ordre de grandeur des doses délivrées en radiodiagnostic.

Radiologists should be able to appreciate the radiation dose delivered to patients for routine diagnostic procedures. The radiology report should include data necessary to calculate the patient dose in Gray. Using the effective dose, it is possible to compare with other source of radiation exposure. Simple formulas, taking into account different anatomical regions, derived from dose-area product (conventional radiography) or dose-length product (CT) are provided to calculate the effective dose in Sievert. For conventional (non-interventional) radiography, the effective dose for a given exam is inferior or equal to the yearly background radiation. For CT, the effective dose corresponds to 1 to 10 years of yearly background radiation.

[Spontaneous subretinal isolated hematomas or associated with macular degeneration: a retrospective review of 95 cases]. / Diagnostic des hématomes sous-rétiniens spontanés isolés ou associés à une dégénérescence maculaire liée à l'âge. Etude rétrospective de 95 cas.

INTRODUCTION: Diagnosis of choroidal hematoma, either spontaneous or associated with age-related macular degeneration, is clinical. In some cases of expansive or posterior lesion, hematoma may be misdiagnosed as a tumor. MRI and color Doppler imaging (CDI) are important in ruling out uveal melanoma in these cases. PATIENTS AND METHODS: We reviewed the clinical, MRI, and ultrasonographic characteristics of 95 patients sent to the Curie Institute for suspected uveal melanoma between 1998 and 2006, whose final diagnosis was a choroidal hematoma. Imaging differences with melanomas are discussed. RESULTS: A total of 95 patients with a diagnosis of hematoma were seen; the age varied from 54 to 92 years with a median age of 77 years; there was a history of macular degeneration in 27 cases and 11 patients were taking an anticoagulant. Intravitreous hemorrhage was noted in 18 cases and the lesion was located in the posterior pole in 28 cases. The thickness of the lesions measured by B scan ultrasonography varied between 1 and 7.8mm, with a mean thickness of 2.86mm. MRI was performed in 27 cases and CDI in ten cases. On CDI, hematomas appeared as linear or regular bulging lesions with no intralesional blood flow. On MRI, hematomas appeared as a high-intensity signal on T1-weighted images, heterogeneous on T2-weigted images in relation to the progression of the clot, but no contrast enhancement was noted inside the lesion. Follow-up examinations showed the progressive involvement of the clot and delayed decreasing size of the lesion. CONCLUSION: The diagnosis of choroidal hematoma is usually made by fundus examination. In some posterior locations with pseudo-tumoral appearance, CDI and MRI are useful to rule out a uveal tumor.

From childhood to adulthood: long-term outcome of medulloblastoma patients. The Institut Curie experience (1980-2000).

Medulloblastoma patients treated at the Institute Curie between 1980 and 2000 were reviewed. Only patients whose primary treatment included craniospinal radiation were considered. Surviving patients were identified and evaluated by means of self-report questionnaires using the Health Utility Index (HUI). Psychosocial functioning, employment, and other health-related indicators were recorded. Seventy-three patients were treated during the study period. At a median follow-up from diagnosis of 14.4 years, 49 patients were alive and 45 surviving patients could be contacted. Late sequelae were frequent, particularly neurological deficits (71%) and endocrine complications (52%). Impairments of psychosocial functioning, including employment, driving capacity, independent living, and marital status, were identified in most patients. Most long-term medulloblastoma survivors suffer persistent deficits in several domains, with a significant impact on their psychosocial functioning. These findings reinforce the importance of early intervention programs for all survivors in order to reduce the psychosocial impacts of their disease.

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.

A significant upward shift in plant species optimum elevation during the 20th century.

Spatial fingerprints of climate change on biotic communities are usually associated with changes in the distribution of species at their latitudinal or altitudinal extremes. By comparing the altitudinal distribution of 171 forest plant species between 1905 and 1985 and 1986 and 2005 along the entire elevation range (0 to 2600 meters above sea level) in west Europe, we show that climate warming has resulted in a significant upward shift in species optimum elevation averaging 29 meters per decade. The shift is larger for species restricted to mountain habitats and for grassy species, which are characterized by faster population turnover. Our study shows that climate change affects the spatial core of the distributional range of plant species, in addition to their distributional margins, as previously reported.

[Differential diagnosis of retinoblastoma: a retrospective study of 486 cases]. / Diagnostic différentiel du rétinoblastome: étude rétrospective de 486 cas.

OBJECTIVES: Detail the most frequent problems encountered in the differential diagnosis of retinoblastoma. PATIENTS: and method: We conducted a retrospective study on the children referred to the Curie Institute for suspicion of retinoblastoma between 2000 and 2006. Diagnosis was made by fundus examination using the indirect ophthalmoscope, ultrasonography, and MRI. RESULTS: Of the 486 children seen during this period, 408 had unilateral or bilateral retinoblastoma and 78 (16%) had another lesion: Coats disease (20 children, 25%), congenital malformations (23 children, 30%; coloboma, PHPV, microphthalmia, isolated or associated with retinal dysplasia), other tumors (10 children, 13%; astrocytomas and medulloepithelioma), combined hamartomas (six children, 8%), inflammatory diseases (six children, 8%) (Toxocara canis, cat scratch eye disease, or toxoplasmosis), and other diseases (13 children, 16%; corneal opacities, congenital cataract, or retinal detachment). DISCUSSION: Compared to previous series, this study shows the proportion of erroneous diagnosis has lowered (16%) compared to earlier studies by Balmer (1986; 30%), and Shields (1991; 42%). No cases of retinopathy of prematurity were seen in our series, demonstrating that screening is good or of a lower frequency in France. The frequency of PHPV has dropped. Coats disease remains a frequent and sometimes difficult diagnosis to make, particularly in advanced stages of the disease.