Arterial spin labelling: predictive role in surgical bleeding of paediatric optic pathway gliomas.

AIM: To analyse the performance of arterial spin labelling (ASL) in predicting surgical bleeding in a paediatric cohort of optic pathway glioma (OPG). MATERIALS AND METHODS: Preoperative ASL data were obtained for 51 OPG in 40 patients, aged from 9 months to 16 years. The relative cerebral blood flow (rCBF) in the tumour areas with the highest CBF (maximum rCBF) was measured and then correlated with qualitative local bleeding (graded no, moderate, and major by the neurosurgeon) and quantitative global surgical bleeding (assessed in millilitres using haematocrit data). RESULTS: Intratumoural maximum rCBF was significantly higher when qualitative local bleeding was high (median value in the no, moderate, and major bleeding groups equal to 0.81, 1.39 and 4.22, respectively, p=0.004), but there was no difference in global quantitative bleeding (p=0.7 for the total blood loss). The maximum tumour rCBF cut-off value of 1.1 yielded a sensitivity of 73%, a specificity of 78%, and an accuracy of 76% (39/51 tumours) in detecting haemorrhagic OPG. Choosing a maximum tumour rCBF cut-off value > 1.7 improved the specificity in diagnosing tumours with high bleeding risk with a specificity of 94%, a sensitivity of 53%, and an accuracy of 82% (42/51 tumours). CONCLUSION: ASL tumoural rCBF is a useful and simple diagnostic tool to help predict high intraoperative tumoural bleeding risk in paediatric OPG.

Arterial Spin-Labeling in the Assessment of Pediatric Nontraumatic Orbital Lesions.

Benign and malignant pediatric orbital lesions can sometimes have overlapping features on conventional MR imaging sequences. MR imaging of 27 children was retrospectively reviewed to describe the signal of some common pediatric extraocular orbital lesions on arterial spin-labeling and to evaluate whether this sequence helps to discriminate malignant from benign masses, with or without ADC value measurements. Qualitative and quantitative assessments of arterial spin-labeling CBF and ADC were performed. All lesions were classified into 3 arterial spin-labeling perfusion patterns: homogeneous hypoperfusion (pattern 1, n = 15; benign lesions), heterogeneous hyperperfusion (pattern 2, n = 9; cellulitis, histiocytosis, malignant tumors), and homogeneous intense hyperperfusion (pattern 3, n = 3; infantile hemangiomas). Arterial spin-labeling can be a valuable tool to improve the diagnostic confidence of some orbital lesions, including infantile hemangioma. An algorithm is proposed.

Arterial Spin-Labeling Perfusion Imaging in the Early Stage of Sturge-Weber Syndrome.

BACKGROUND AND PURPOSE: Sturge-Weber syndrome is a rare congenital neuro-oculo-cutaneous disorder. Although the principal mechanism of Sturge-Weber syndrome is characterized by a leptomeningeal vascular malformation, few data regarding perfusion abnormalities of the brain parenchyma are available. Therefore, the aim of this study was to assess the diagnostic performance of arterial spin-labeling perfusion imaging in the early stage of Sturge-Weber syndrome before 1 year of age until 3.5 years of age. We hypothesized that a leptomeningeal vascular malformation has very early hypoperfusion compared with controls with healthy brains. MATERIALS AND METHODS: We compared the CBF using arterial spin-labeling perfusion imaging performed at 3T MR imaging in the brain parenchymal regions juxtaposing the leptomeningeal vascular malformation in patients with Sturge-Weber syndrome (n = 16; 3.5 years of age or younger) with the corresponding areas in age-matched controls with healthy brains (n = 58). The analysis was performed following two complementary methods: a whole-brain voxel-based analysis and a visual ROI analysis focused on brain territory of the leptomeningeal vascular malformation. RESULTS: Whole-brain voxel-based comparison revealed a significant unilateral decrease in CBF localized in the affected cortices of patients with Sturge-Weber syndrome (P < .001). CBF values within the ROIs in patients with Sturge-Weber syndrome were lower than those in controls (in the whole cohort: median, 25 mL/100g/min, versus 44 mL/100g/min; P < .001). This finding was also observed in the group younger than 1 year of age, emphasizing the high sensitivity of arterial spin-labeling in this age window in which the diagnosis is difficult. CONCLUSIONS: Arterial spin-labeling perfusion imaging in the early stage of Sturge-Weber syndrome can help to diagnose the disease by depicting a cortical hypoperfusion juxtaposing the leptomeningeal vascular malformation.

Noninvasive Follow-up Imaging of Ruptured Pediatric Brain AVMs Using Arterial Spin-Labeling.

BACKGROUND AND PURPOSE: Brain AVMs represent the main etiology of pediatric intracranial hemorrhage. Noninvasive imaging techniques to monitor the treatment effect of brain AVMs remain an unmet need. In a large cohort of pediatric ruptured brain AVMs, we aimed to investigate the role of arterial spin-labeling for the longitudinal follow-up during treatment and after complete obliteration by analyzing CBF variations across treatment sessions. MATERIALS AND METHODS: Consecutive patients with ruptured brain AVMs referred to a pediatric quaternary care center were prospectively included in a registry that was retrospectively queried for children treated between 2011 and 2019 with unimodal or multimodal treatment (surgery, radiosurgery, embolization). We included children who underwent an arterial spin-labeling sequence before and after treatment and a follow-up DSA. CBF variations were analyzed in univariable analyses. RESULTS: Fifty-nine children with 105 distinct treatment sessions were included. The median CBF variation after treatment was -43 mL/100 mg/min (interquartile range, -102-5.5), significantly lower after complete nidal surgical resection. Following radiosurgery, patients who were healed on the last DSA follow-up demonstrated a greater CBF decrease on intercurrent MR imaging, compared with patients with a persisting shunt at last follow-up (mean, -62 [SD, 61] mL/100 mg/min versus -17 [SD, 40.1] mL/100 mg/min; P = .02). In children with obliterated AVMs, recurrences occurred in 12% and resulted in a constant increase in CBF (mean, +89 [SD, 77] mL/100 mg/min). CONCLUSIONS: Our results contribute data on the role of noninvasive arterial spin-labeling monitoring of the response to treatment or follow-up after obliteration of pediatric AVMs. Future research may help to better delineate how arterial spin-labeling can assist in decisions regarding the optimal timing for DSA.

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.

Imaging features of medulloblastoma: Conventional imaging, diffusion-weighted imaging, perfusion-weighted imaging, and spectroscopy: From general features to subtypes and characteristics.

Medulloblastoma is a frequent high-grade neoplasm among pediatric brain tumours. Its classical imaging features are a midline tumour growing into the fourth ventricle, hyperdense on CT-scan, displaying a hypersignal when using diffusion-weighted imaging, with a variable contrast enhancement. Nevertheless, atypical imaging features have been widely reported, varying according to the age of the patient, and histopathological subtype. In this study, we review the classical and atypical imaging features of medulloblastomas, with emphasis on advanced MRI techniques, histopathological and molecular subtypes and characteristics, and follow-up modalities.

Focal Areas of High Signal Intensity in Children with Neurofibromatosis Type 1: Expected Evolution on MRI.

BACKGROUND AND PURPOSE: Focal areas of high signal intensity are T2WI/T2-FLAIR hyperintensities frequently found on MR imaging of children diagnosed with neurofibromatosis type 1, often thought to regress spontaneously during adolescence or puberty. Due to the risk of tumor in this population, some focal areas of high signal intensity may pose diagnostic problems. The objective of this study was to assess the characteristics and temporal evolution of focal areas of high signal intensity in children with neurofibromatosis type 1 using long-term follow-up with MR imaging. MATERIALS AND METHODS: We retrospectively examined the MRIs of children diagnosed with neurofibromatosis type 1 using the National Institutes of Health Consensus Criteria (1987), with imaging follow-up of at least 4 years. We recorded the number, size, and surface area of focal areas of high signal intensity according to their anatomic distribution on T2WI/T2-FLAIR sequences. A generalized mixed model was used to analyze the evolution of focal areas of high signal intensity according to age, and separate analyses were performed for girls and boys. RESULTS: Thirty-nine patients (ie, 285 MR images) with a median follow-up of 7 years were analyzed. Focal areas of high signal intensity were found in 100% of patients, preferentially in the infratentorial white matter (35% cerebellum, 30% brain stem) and in the capsular lenticular region (22%). They measured 15 mm in 95% of cases. They appeared from the age of 1 year; increased in number, size, and surface area to a peak at the age of 7; and then spontaneously regressed by 17 years of age, similarly in girls and boys. CONCLUSIONS: Focal areas of high signal intensity are mostly small (<15 mm) abnormalities in the posterior fossa or capsular lenticular region. Our results suggest that the evolution of focal areas of high signal intensity is not related to puberty with a peak at the age of 7 years. Knowledge of the predictive evolution of focal areas of high signal intensity is essential in the follow-up of children with neurofibromatosis type 1.

Incidental Brain MRI Findings in Children: A Systematic Review and Meta-Analysis.

BACKGROUND: The detection of incidental findings on children's brain MR imaging poses various practical issues because the life-long implications of such findings may be profound. PURPOSE: Our aim was to assess the prevalence and characteristics of incidental brain MR imaging findings in children. DATA SOURCES: Electronic databases (PubMed, EMBASE, and Cochrane) were searched for articles published between 1985 to July 2018, with the following search terms: "incidental," "findings," "brain," "MR imaging." STUDY SELECTION: Inclusion criteria were the following: 1) patients younger than 21 years of age, 2) healthy children without any clinical condition, 3) MR images obtained with at least a 1.5T magnet, 4) original articles, and 5) a methodologic quality score of ≥10. DATA ANALYSIS: Two observers independently extracted data and assessed data quality and validity. The number and type of incidental findings were pooled. Heterogeneity was assessed using the Cochran Q statistic and the I2 statistic. DATA SYNTHESIS: Seven studies were included, reporting 5938 children (mean age, 11.3 ± 2.8 years). Incidental findings were present in 16.4% (99% CI, 9.8-26.2; Q = 117.5, I2= 94.9%) of healthy children, intracranial cysts being the most frequent (10.2%, 99% CI, 3.1-28.5; Q = 306.4, I2 = 98.0%). Nonspecific white matter hyperintensities were reported in 1.9% (99% CI, 0.2-16.8; Q = 73.6, I2 = 94.6%), Chiari 1 malformation was found in 0.8% (99% CI, 0.5-1.3; Q = 7.6, I2 = 60.5%), and intracranial neoplasms were reported in 0.2% (99% CI, 0.1-0.6; Q = 3.4, I2 = 12.3%). In total, the prevalence of incidental findings needing follow-up was 2.6% (99% CI, 0.5-11.7; Q = 131.2, I2 = 95.4%). Incidental findings needing specific treatment were brain tumors (0.2%) and cavernomas (0.2%). LIMITATIONS: Limitations were no age stratification or ethnicity data and variation in the design of included studies. CONCLUSIONS: The prevalence of incidental findings is much more frequent in children than previously reported in adults, but clinically meaningfull incidental findings were present in <1 in 38 children.

CT and Multimodal MR Imaging Features of Embryonal Tumors with Multilayered Rosettes in Children.

BACKGROUND AND PURPOSE: Embryonal tumors with multilayered rosettes, C19MC-altered, are brain tumors occurring in young children, which were clearly defined in the 2016 World Health Organization classification of central nervous system neoplasms. Our objective was to describe the multimodal imaging characteristics of this new entity. MATERIALS AND METHODS: We performed a retrospective monocentric review of embryonal brain tumors and looked for embryonal tumors with multilayered rosettes with confirmed C19MC alteration. We gathered morphologic imaging data, as well as DWI and PWI data (using arterial spin-labeling and DSC). RESULTS: We included 16 patients with a median age of 2 years 8 months. Tumors were both supratentorial (56%, 9/16) and infratentorial (44%, 7/16). Tumors were large (median diameter, 59 mm; interquartile range, 48-71 mm), with absent (75%, 12/16) or minimal (25%, 4/16) peritumoral edema. Enhancement was absent (20%, 3/15) or weak (73%, 11/15), whereas intratumoral macrovessels were frequently seen (94%, 15/16) and calcifications were present in 67% (10/15). Diffusion was always restricted, with a minimal ADC of 520 mm2/s (interquartile range, 495-540 mm2/s). Cerebral blood flow using arterial spin-labeling was low, with a maximal CBF of 43 mL/min/100 g (interquartile range, 33-55 mL/min/100 g 5). When available (3 patients), relative cerebral blood volume using DSC was high (range, 3.5-5.8). CONCLUSIONS: Embryonal tumors with multilayered rosettes, C19MC-altered, have characteristic imaging features that could help in the diagnosis of this rare tumor in young children.

Arterial Spin-Labeling to Discriminate Pediatric Cervicofacial Soft-Tissue Vascular Anomalies.

BACKGROUND AND PURPOSE: Differentiating major subtypes of cervicofacial vascular lesions is crucial for appropriate management. The aim of our study was to evaluate the performance of an MR imaging arterial spin-labeling perfusion sequence in discriminating pediatric cervicofacial soft-tissue vascular anomalies. MATERIALS AND METHODS: We conducted a retrospective analysis of data from a prospectively maintained registry including pediatric patients at a tertiary pediatric center between January 2012 and January 2014. We included pediatric patients with a final diagnosis of soft-tissue vascular anomalies and an MR imaging, including an arterial spin-labeling sequence at presentation. We performed an analysis of lesion perfusion, blinded to clinical data, by using concurrent spiral 3D pseudocontinuous arterial spin-labeling (1.5T magnet; spiral matrix, 512 × 8 mm; postlabeling delay, 1025 ms). Lesional flow was recorded with calibrated intralesional ROIs. Perfusion characteristics were compared among lesion subtypes with the Mood Median test. RESULTS: Among 840 patients screened, 46 matched the inclusion criteria and were included (median age, 1.45 years; interquartile range, 0.4-5.1 years; 27 females). Hemangiomas, including infantile hemangiomas (n = 18 patients) and noninvoluting (n = 2) and rapidly involuting (n = 1) congenital types, demonstrated marked hyperperfusion (median flow, 436 mL/min/100 g; interquartile range, 212.5-603 mL/min/100 g), significantly higher than that of lymphatic malformations (median, 22.5 mL/min/100 g; interquartile range, 16-60 mL/min/100 g; P < .001) or venous malformations (median, 25 mL/min/100 g; interquartile range, 15-66.5 mL/min/100 g; P = .003). CONCLUSIONS: MR imaging arterial spin-labeling is a valuable tool for the assessment of soft-tissue vascular anomaly hemodynamics and for the classification of major lesion subtypes.

Academic productivity of French radiology residents: Where do we stand?

RATIONALE AND OBJECTIVES: Although medical research by French radiology residents is encouraged, their publication productivity remains unknown. Thus, we aimed to assess and analyze the publication rate of medical theses and the overall academic productivity of radiology residents who graduated in 2009 and 2010. MATERIALS AND METHODS: The list of radiology residents and imaging theses were obtained from the French internet database of university theses. The main characteristics of the theses were recorded and correlated with associated publications identified by scanning the PubMed database. All other publications by French radiology residents not related to the theses were also obtained, described and compared to published theses. RESULTS: Seventy-nine out of 224 (35.3%) medical theses written by French radiology residents in 2009 and 2010 were transformed into articles published in Medline-indexed journals. Residents were first authors in 69% (60/87) of these articles. The factors associated with publication of the thesis were a prospective design (P=0.01) and the publication as a first author of an original study not related to the thesis (P=0.01). Seventy-one percent of the residents had published at least one other article, including 36.6% as first authors. CONCLUSION: Academic productivity of French radiology residents is high thanks to published theses and other articles.

Choroid Plexus Neoplasms: Toward a Distinction between Carcinoma and Papilloma Using Arterial Spin-Labeling.

Pediatric choroid plexus papillomas and carcinomas are highly vascularized neoplasms, which are difficult to distinguish with conventional imaging. We aimed to analyze the diagnostic accuracy of PWI, by using both pseudocontinuous arterial spin-labeling and DSC-PWI. We reviewed the PWI of 13 children with choroid plexus neoplasms (7 papillomas and 6 carcinomas). We quantified CBF, relative CBF, and relative CBV in each lesion and compared papillomas and carcinomas. Relative CBF values by using arterial spin-labeling were significantly higher for carcinomas (P = .028). The median value of relative CBF was 1.7 (range, 1.4-1.9) for carcinomas and 0.4 (range, 0.3-0.6) for papillomas. The CBF median value was 115 mL/min/100 g (range, 90-140 mL/min/100 g) for carcinomas and 41 mL/min/100 g (range, 10-73 mL/min/100 g) for papillomas (P = .056). Measures with DSC-PWI were more variable and not significantly different (P = .393). Arterial spin-labeling is a promising technique to differentiate choroid plexus carcinomas and papillomas.

Analysis of subsequent publication of scientific orally presented abstracts of the French National Congress of Radiology. Part II: Focus on the French abstracts.

AIM: To evaluate the publication rate of scientific abstracts that were presented orally at the 2008, 2009, and 2010 annual meetings of the French Society of Radiology by French radiologists, and to perform a French regional analysis. MATERIAL AND METHODS: Orally presented abstracts were identified by examining online abstract books of the 2008, 2009, and 2010 annual meetings of the French Society of Radiology, and cross-checked by reviewing the paper version of abstracts for the same period. Only abstracts from French teams were selected. The administrative region of submission was noted for each abstract and for each region the total population, the number of active radiologists, the number of active members of the French Society of Radiology and the number of academic radiologists were noted. Imaging subspecialties were also noted. RESULTS: 625 abstracts were identified resulting in 268 publications (publication rate: 43%). The median number of presentations and publications per region was 18 (range: 1-255) and 7 (range: 0-101), respectively. The ratio per million inhabitants was 7.5 and 3 respectively. The median number of presentations and publications per 100 active radiologists (respectively members of the FSR) was 7 and 3 (respectively 10 and 4). The median number of presentations and publications per academic radiologist were 2.6, and 1.2, respectively. The regional variations for each indicator were high (40-180%). Three subspecialties had a publication rate of more than 50%: thoracic imaging (58%), abdominal imaging (52%), and genitourinary imaging (51%). CONCLUSION: The publication rate of orally presented French scientific abstracts was high, with important variations according to the regions of origin and imaging subspecialties.

Analysis of subsequent publication of scientific orally presented abstracts of the French national congress of radiology. Part I: General characteristics.

PURPOSE: To evaluate the publication rate of scientific abstracts orally presented at the annual meeting of the French Society of Radiology (FSR), and to identify factors associated with publication. MATERIAL AND METHODS: Abstracts were selected from the books of abstracts of the 2008-2010 annual meetings of the FSR. For each abstract, country of origin, diagnostic/interventional radiology, imaging techniques (plain radiography, angiography, ultrasound [US], computed tomography [CT], magnetic resonance imaging [MRI]), human/experimental study, retrospective/prospective design, number of subjects, oncologic study or not were noted. Publications were searched in Medline-indexed journals and factors associated analyzed by multivariate analysis. RESULTS: Seven hundred and forty-four abstracts lead to 298 publications (publication rate 40%). Most abstracts reported retrospective studies (61%), in humans (94%), diagnostic imaging (85%), from European authors (90%), and oncology (27%). Median number of subject was 39 (19-87). Main imaging techniques were MRI, CT, US (46%, 29%, 21%). Publications were mostly in English (89%), in radiological journals (72%), with a mean 3.5±3.7 impact factor. Publication was associated with a prospective design (OR=1.80), a submission from Europe (OR=1.71), angiography (OR=2.44), and oncology (OR=1.81). CONCLUSION: The annual meeting of the FSR is in French, but the rate of publication of presented abstracts is high, mostly in English in reputable journals.