Increased Musculoskeletal Deformities And Decreased Lung Volume In Patients After Ea/Tef Repair - A Real-Time Mri Study.

OBJECTIVE: This study aims to assess morphological and functional postoperative changes after open or minimally invasive (MIS) repair of esophageal atresia (EA) compared to healthy controls by thoracic real-time MRI. SUMMARY BACKGROUND DATA: Musculoskeletal deformities and pulmonary morbidity are common in children after EA repair. The real-time MRI is a novel technique that provides ultrafast, high-quality images during spontaneous breathing, without sedation even in young children. METHODS: Children aged 3-18 years were prospectively examined with a 3 Tesla MRI. Musculoskeletal deformities, static thoracic cross-sectional areas (CSA) at three different levels and lung volumes, as well as dynamic right-to-left ratio of CSA of hemithoraces and lung volumes during forced breathing were evaluated. RESULTS: 72 children (42 open, 8 MIS, 22 controls) were recruited. In the EA group, rib fusions and adhesions (78%, P<0.01) and scoliosis (15%, P=0.32) were found after thoracotomy, but not after MIS. Mean right-to-left ratio of CSA and lung volumes were lower after EA repair compared to controls (P <0.05), indicating impaired thoracic and lung development. The number of thoracotomies was a significant risk factor for smaller thoracic volumes (P<0.05). CONCLUSIONS: For the first time, morphological changes and thoracic motility after EA repair were visualized by dynamic real-time MRI. Children after EA repair show decreased right-sided thoracic and lung development compared to controls. Open repair leads to significantly more musculoskeletal deformities. This study emphasizes that musculoskeletal morbidity following a thoracotomy in infancy is high.

Brain deposition of gadobutrol in children-a cross-sectional and longitudinal MRI T1 mapping study.

OBJECTIVES: Depositions of linear gadolinium-based MRI contrast agents are readily visible in T1-weighted MRIs of certain brain regions in both adults and children. Macrocyclic contrast agents such as gadobutrol have so far escaped detection by qualitative MRI in children. This study aimed to assess whether there is evidence for deposition of gadobutrol in children using quantitative T1 mapping. METHODS: This retrospective study included patients, naive to other gadolinium-based contrast agents than gadobutrol, who had received gadobutrol as part of a clinically indicated MRI. For each patient, T1 relaxation times at 3 T were measured using single-shot T1 mapping at two time points. In each of six brain regions, age-adjusted T1 relaxation times were correlated with a number of previous gadobutrol administrations. To combine interindividual, cross-sectional effects with intraindividual, longitudinal effects, both linear mixed model and generalized additive mixed model were applied. RESULTS: One hundred four examinations of 52 children (age median 11.4, IQR 6.3-15, 26 female) with a median of 7 doses of gadobutrol in the history of their neurological or neurooncological disease were included. After correction for age and indeterminate disease-related effects to T1 time, a negative correlation of T1 time with the number of gadobutrol doses administered was observed in both mixed models in the putamen (beta - 1.65, p = .03) and globus pallidus (beta - 1.98, p = .012) CONCLUSIONS: The results indicate that in children, gadobutrol is deposited in the globus pallidus and putamen. KEY POINTS: • Previous gadobutrol administration correlates with reduced T1 relaxation times in the globus pallidus and putamen in children. • This decreased T1 might be caused by gadobutrol retention within these gray-matter nuclei.

Pectus excavatum in motion: dynamic evaluation using real-time MRI.

OBJECTIVES: The breathing phase for the determination of thoracic indices in patients with pectus excavatum is not standardized. The aim of this study was to identify the best period for reliable assessments of morphologic indices by dynamic observations of the chest wall using real-time MRI. METHODS: In this prospective study, patients with pectus excavatum underwent morphologic evaluation by real-time MRI at 3 T between January 2020 and June 2021. The Haller index (HI), correction index (CI), modified asymmetry index (AI), and modified eccentricity index (EI) were determined during free, quiet, and forced breathing respectively. Breathing-related differences in the thoracic indices were analyzed with the Wilcoxon signed-rank test. Motion of the anterior chest wall was analyzed as well. RESULTS: A total of 56 patients (11 females and 45 males, median age 15.4 years, interquartile range 14.3-16.9) were included. In quiet expiration, the median HI in the cohort equaled 5.7 (4.5-7.2). The median absolute differences (Δ) in the thoracic indices between peak inspiration and peak expiration were ΔHI = 1.1 (0.7-1.6, p < .001), ΔCI = 4.8% (1.3-7.5%, p < .001), ΔAI = 3.0% (1.0-5.0%, p < .001), and ΔEI = 8.0% (3.0-14.0%, p < .05). The indices varied significantly during different inspiratory phases, but not during expiration (p > .05 each). Furthermore, the dynamic evaluation revealed three distinctive movement patterns of the funnel chest. CONCLUSIONS: Real-time MRI reveals patterns of chest wall motion and indicate that thoracic indices of pectus excavatum should be assessed in the end-expiratory phase of quiet expiration. KEY POINTS: • The thoracic indices in patients with pectus excavatum depend on the breathing phase. • Quiet expiration represents the best breathing phase for determining thoracic indices. • Real-time MRI can identify different chest wall motion patterns in pectus excavatum.

Real-time MRI: a new tool of radiologic imaging in small children.

Real-time MRI (rt-MRI) in children is a new imaging technique that combines the advantages of US - at frame rates of up to 50 images per second - with the quality and features of MRI. Although still subject of research, it has become a standard tool in the diagnostic portfolio of two pediatric radiology departments in Germany. Based on ultrashort acquisition times, any detrimental effects of macroscopic movements of the child and the physiological movements of the organs are negligible. Especially in pediatric brain imaging, rt-MRI has already proven its value. With suitable indications, rt-MRI can reduce anesthesia and sedation examinations in children below 6 years of age by 40% due to its very short examination time and its robustness to motion. There is a high level of acceptance among parents and referrers when diagnostic possibilities and limitations are communicated correctly. CONCLUSION: Completely new diagnostic possibilities arise in the imaging of the moving lung, the beating heart, joint movements, and speaking and swallowing, as demonstrated in this video-backed review. WHAT IS KNOWN: • MRI in moving children has been burdened with severe artifacts. • Gross motion usually has to be handled by sedation and periodic motion of the heart and lungs has to be compensated with time-consuming techniques until now. WHAT IS NEW: • Real-time MRI allows image acquisition with up to 50 frames per second similar to ultrasound frame rate. • Real-time MRI proofs to be very promising for imaging children, reducing examination time and sedation rate drastically.

Chest magnetic resonance imaging in cystic fibrosis: technique and clinical benefits.

Cystic fibrosis (CF) is one of the most common inherited and life-shortening pulmonary diseases in the Caucasian population. With the widespread introduction of newborn screening and the development of modulator therapy, tremendous advances have been made in recent years both in diagnosis and therapy. Since paediatric CF patients tend to be younger and have lower morbidity, the type of imaging modality that should be used to monitor the disease is often debated. Computed tomography (CT) is sensitive to many pulmonary pathologies, but radiation exposure limits its use, especially in children and adolescents. Conventional pulmonary magnetic resonance imaging (MRI) is a valid alternative to CT and, in most cases, provides sufficient information to guide treatment. Given the expected widespread availability of sequences with ultra-short echo times, there will be even fewer reasons to perform CT for follow-up of patients with CF. This review aims to provide an overview of the process and results of monitoring CF with MRI, particularly for centres not specialising in the disease.

Chest examinations in children with real-time magnetic resonance imaging: first clinical experience.

BACKGROUND: Real-time magnetic resonance imaging (MRI) based on a fast low-angle shot technique 2.0 (FLASH 2.0) is highly effective against artifacts caused due to the bulk and pulmonary and cardiac motions of the patient. However, to date, there are no reports on the application of this innovative technique to pediatric lung MRI. OBJECTIVE: This study aimed to identify the limits of resolution and image quality of real-time lung MRI in children and to assess the types and minimal size of lesions with these new sequences. MATERIALS AND METHODS: In this retrospective study, pathological lung findings in 87 children were classified into 6 subgroups, as detected on conventional MRI: metastases and tumors, consolidation, scars, hyperinflation, interstitial pathology and bronchiectasis. Subsequently, the findings were grouped according to size (4-6 mm, 7-9 mm and ≥ 10 mm) and evaluated for visual delineation of the findings (0 = not visible, 1 = hardly visible and 2 = well visualized). RESULTS: Real-time MRI allows for diagnostic, artifact-free thorax images to be obtained, regardless of patient movements. The delineation of findings strongly correlates with the size of the pathology. Metastases, consolidation and scars were visible at 100% when larger than 9 mm. In the 7-9 mm subgroup, the visibility was 83% for metastases, 88% for consolidation and 100% for scars in T2/T1 weighting. Though often visible, smaller pathological lesions of 4-6 mm in size did not regularly meet the expected diagnostic confidence: The visibility of metastases was 18%, consolidation was 64% and scars was 71%. Diffuse interstitial lung changes and hyperinflation, known as "MR-minus pathologies," were not accessible to real-time MRI. CONCLUSION: The method provides motion robust images of the lung and thorax. However, the lower sensitivity for small lung lesions is a major limitation for routine use of this technique. Currently, the method is adequate for diagnosing inflammatory lung diseases, atelectasis, effusions and lung scarring in children with irregular breathing patterns or bulk motion on sedation-free MRI. A medium-term goal is to improve the diagnostic accuracy of small nodules and interstitial lesions.

Quantitative T1 mapping of the normal brain from early infancy to adulthood.

BACKGROUND: Quantitative mapping of MRI relaxation times is expected to uncover pathological processes in the brain more subtly than standard MRI techniques with weighted contrasts. So far, however, most mapping techniques suffer from a long measuring time, low spatial resolution or even sensitivity to magnetic field inhomogeneity. OBJECTIVE: To obtain T1 relaxation times of the normal brain from early infancy to adulthood using a novel technique for fast and accurate T1 mapping at high spatial resolution. MATERIALS AND METHODS: We performed whole-brain T1 mapping within less than 3 min in 100 patients between 2 months and 18 years of age with normal brain at a field strength of 3 T. We analyzed T1 relaxation times in several gray-matter nuclei and white matter. Subsequently, we derived regression equations for mean value and confidence interval. RESULTS: T1 relaxation times of the pediatric brain rapidly decrease in all regions within the first 3 years of age, followed by a significantly weaker decrease until adulthood. These characteristics are more pronounced in white matter than in deep gray matter. CONCLUSION: Regardless of age, quantitative T1 mapping of the pediatric brain is feasible in clinical practice. Normal age-dependent values should contribute to improved discrimination of subtle intracerebral alterations.

Real-time magnetic resonance imaging in pediatric radiology - new approach to movement and moving children.

The recent development of highly undersampled radial gradient echo sequences in combination with nonlinear inverse image reconstruction now allows for MRI examinations in real time. Image acquisition times as short as 20 ms yield MRI videos with rates of up to 50 frames per second with spin density, T1- and T2-type contrast. The addition of an initial 180° inversion pulse achieves accurate T1 mapping within only 4 s. These technical advances promise specific advantages for studies of infants and young children by eliminating the need for sedation or anesthesia. Our preliminary data demonstrate new diagnostic opportunities ranging from dynamic studies of speech and swallowing processes and body movements to a rapid volumetric assessment of brain cerebrospinal fluid spaces in only few seconds. Real-time MRI of the heart and blood flow can be performed without electrocardiogram gating and under free breathing. The present findings support the idea that real-time MRI will complement existing methods by providing long-awaited diagnostic options for patients in early childhood. Major advantages are the avoidance of sedation or anesthesia and the yet unexplored potential to gain insights into arbitrary body functions.

[Lymphoma in children and adolescents]. / Lymphomerkrankungen im Kindes- und Jugendalter.

CLINICAL/METHODOLOGICAL ISSUE: Lymphoma is the third most common neoplasm in children. Detection, accurate staging, and restaging are important for all radiologists involved in the diagnosis of children. STANDARD RADIOLOGICAL METHODS: Magnetic resonance imaging (MRI), positron emission tomography/computed tomography (PET/CT), CT, ultrasound, X­ray. METHODOLOGICAL INNOVATIONS: Whole-body imaging (MRI and PET-MRI or PET-CT) play a key role in diagnostics and for therapy selection in Hodgkin lymphoma. PERFORMANCE: In particular, hybrid imaging using 18F­FDG PET is proving to be a powerful method for staging and restaging. ACHIEVEMENTS: Standardization of imaging and inclusion in therapy studies (e.g. within the framework of the EuroNet-PHL-C2 study) improves diagnostics and simultaneously reduces therapy-related side effects. PRACTICAL RECOMMENDATIONS: In Hodgkin lymphoma, deviations from the prescribed diagnostic procedure should be avoided. In clinically very heterogeneous non-Hodgkin lymphoma (NHL), on the other hand, the diagnostic procedure should be adapted to the actual clinical condition of the child. The role of interim PET in NHL is currently still the subject of clinical discussion.

Hypomorphic Pathogenic Variants in TAF13 Are Associated with Autosomal-Recessive Intellectual Disability and Microcephaly.

In two independent consanguineous families each with two children affected by mild intellectual disability and microcephaly, we identified two homozygous missense variants (c.119T>A [p.Met40Lys] and c.92T>A [p.Leu31His]) in TATA-box-binding-protein-associated factor 13 (TAF13). Molecular modeling suggested a pathogenic effect of both variants through disruption of the interaction between TAF13 and TAF11. These two proteins form a histone-like heterodimer that is essential for their recruitment into the general RNA polymerase II transcription factor IID (TFIID) complex. Co-immunoprecipitation in HeLa cells transfected with plasmids encoding TAF11 and TAF13 revealed that both variants indeed impaired formation of the TAF13-TAF11 heterodimer, thus confirming the protein modeling analysis. To further understand the functional role of TAF13, we performed RNA sequencing of neuroblastoma cell lines upon TAF13 knockdown. The transcriptional profile showed significant deregulation of gene expression patterns with an emphasis on genes related to neuronal and skeletal functions and those containing E-box motives in their promoters. Here, we expand the spectrum of TAF-associated phenotypes and highlight the importance of TAF13 in neuronal functions.

[Current Treatment of Esophageal Atresia with Tracheoesophageal Fistula - Updated Guidelines of the German Society of Pediatric Surgery]. / Behandlung der Ösophagusatresie mit unterer tracheoösophagealer Fistel ­ Zusammenfassung der aktuellen S2K-Leitlinie der DGKCH.

Esophageal atresia (EA) is a congenital anomaly that entails an interrupted esophagus with or without tracheoesophageal fistula (TEF). Depending on the distance of the two esophageal pouches a "short-gap" is distinguished from a "long-gap" variant. Up to 50% of newborns have additional anomalies. EA is prenatally diagnosed in 32-63% of cases. Recently, the interdisciplinary care in these children underwent substantial changes. Therefore, we summarize the current guideline of the German society of pediatric surgery for the treatment of patients with EA and distal TEF (Gross Type C). Controversies regarding the perioperative management include surgical-technical aspects, such as the thoracoscopic approach to EA, as well as general anesthesia (preoperative tracheobronchoscopy, intraoperative hypercapnia and acidosis). Moreover, postoperative complications and their management like anastomotic stricture are outlined. Despite significant improvements in the treatment of EA, there is still a relevant amount of long-term morbidity after surgical correction. This includes dysmotility of the esophagus, gastroesophageal reflux disease, recurrent respiratory infections, tracheomalacia, failure to thrive, and orthopedic complications following thoracotomy in the neonatal age. Therefore, close follow-up is mandatory to attain optimal quality of life.

Outpacing movement - ultrafast volume coverage in neuropediatric magnetic resonance imaging.

BACKGROUND: Conventional MRI sequences are often affected in neuropediatric imaging by unavoidable movements. Therefore, children younger than 6 years usually have to be examined under sedation/anesthesia. A new real-time MRI technique with automatic slice advancement allows for motion-robust T2-weighted volume coverage of the whole brain within a few seconds in adults. OBJECTIVE: To evaluate to which extent the new volume coverage method can be used to visualize cerebrospinal fluid and reduce the need for anesthesia in children. MATERIALS AND METHODS: We assessed 30 children ages 6 years and younger with suspected or proven hydrocephalus, hygroma or macrocephalus using volume coverage sequences with 20 slices per second in three planes. If necessary, a parent was placed in the bore together with the child for calming and gentle immobilization. We compared visualization of cerebrospinal fluid spaces and course of the shunt catheter in volume coverage sequences vs. fast spin-echo sequences. RESULTS: The clinical issue could be sufficiently assessed in all children with use of volume coverage sequences, whereas conventional fast spin-echo sequences performed moderately to poorly. Visualization of the tip of a shunt failed in 16% of volume coverage scans and 27% of turbo spin-echo scans. A subsequent examination under anesthesia was never necessary. None of the examinations had to be stopped prematurely. CONCLUSION: The motion-robust volume coverage sequences with T2-type contrast can be used to avoid sedation of children in the evaluation of cerebrospinal fluid spaces, even in the presence of vigorous motion. For other indications and contrasts, the technique must still be evaluated.

The current status and further prospects for lung magnetic resonance imaging in pediatric radiology.

Lung MRI makes it possible to replace up to 90% of CT examinations with radiation-free magnetic resonance diagnostics of the lungs without suffering any diagnostic loss. The individual radiation exposure can thus be relevantly reduced. This applies in particular to children who repeatedly require sectional imaging of the lung, e.g., in tumor surveillance or in chronic lung diseases such as cystic fibrosis. In this paper we discuss various factors that favor the establishment of lung MRI in the clinical setting. Among the many sequences proposed for lung imaging, respiration-triggered T2-W turbo spin-echo (TSE) sequences have been established as a good standard for children. Additional sequences are mostly dispensable. The most important pulmonary findings are demonstrated here in the form of a detailed pictorial essay. T1-weighted gradient echo sequences with ultrashort echo time are a new option. These sequences anticipate signal loss in the lung and deliver CT-like images with high spatial resolution. When using self-gated T1-W ultrashort echo time 3-D sequences that acquire iso-voxel geometry in the sub-millimeter range, secondary reconstructions are possible.

Management strategies for children with COVID-19: ESPR practical recommendations.

During the outbreak of the COVID-19 pandemic, guidelines have been issued by international, national and local authorities to address management and the need for preparedness. Children with COVID-19 differ from adults in that they are less often and less severely affected. Additional precautions required in the management of children address their increased radiosensitivity, need for accompanying carers, and methods for dealing with children in a mixed adult-paediatric institution. In this guidance document, our aim is to define a pragmatic strategy for imaging children with an emphasis on proven or suspected COVID-19 cases. Children suspected of COVID-19 should not be imaged routinely. Imaging should be performed only when expected to alter patient management, depending on symptoms, preexisting conditions and clinical evolution. In order to prevent disease transmission, it is important to manage the inpatient caseload effectively by triaging children and carers outside the hospital, re-scheduling nonurgent elective procedures and managing symptomatic children and carers as COVID-19 positive until proven otherwise. Within the imaging department one should consider conducting portable examinations with COVID-19 machines or arranging dedicated COVID-19 paediatric imaging sessions and performing routine nasopharyngeal swab testing before imaging under general anaesthesia. Finally, regular personal hygiene, appropriate usage of personal protective equipment, awareness of which procedures are considered aerosol generating and information on how to best disinfect imaging machinery after examinations should be highlighted to all staff members.

Thoracic imaging of coronavirus disease 2019 (COVID-19) in children: a series of 91 cases.

BACKGROUND: Pulmonary infection with SARS-CoV-2 virus (severe acute respiratory syndrome coronavirus 2; COVID-19) has rapidly spread worldwide to become a global pandemic. OBJECTIVE: To collect paediatric COVID-19 cases worldwide and to summarize both clinical and imaging findings in children who tested positive on polymerase chain reaction testing for SARS-CoV-2. MATERIALS AND METHODS: Data were collected by completion of a standardised case report form submitted to the office of the European Society of Paediatric Radiology from March 12 to April 8, 2020. Chest imaging findings in children younger than 18 years old who tested positive on polymerase chain reaction testing for SARS-CoV-2 were included. Representative imaging studies were evaluated by multiple senior paediatric radiologists from this group with expertise in paediatric chest imaging. RESULTS: Ninety-one children were included (49 males; median age: 6.1 years, interquartile range: 1.0 to 13.0 years, range: 9 days-17 years). Most had mild symptoms, mostly fever and cough, and one-third had coexisting medical conditions. Eleven percent of children presented with severe symptoms and required intensive unit care. Chest radiographs were available in 89% of patients and 10% of them were normal. Abnormal chest radiographs showed mainly perihilar bronchial wall thickening (58%) and/or airspace consolidation (35%). Computed tomography (CT) scans were available in 26% of cases, with the most common abnormality being ground glass opacities (88%) and/or airspace consolidation (58%). Tree in bud opacities were seen in 6 of 24 CTs (25%). Lung ultrasound and chest magnetic resonance imaging were rarely utilized. CONCLUSION: It seems unnecessary to perform chest imaging in children to diagnose COVID-19. Chest radiography can be used in symptomatic children to assess airway infection or pneumonia. CT should be reserved for when there is clinical concern to assess for possible complications, especially in children with coexisting medical conditions.

Severe gyration and migration disorder in fetofetal transfusion syndrome: two case reports and a review of the literature on the neurological outcome of children with lesions on neuroimaging.

INTRODUCTION: Fetofetal transfusion syndrome is a dreaded cause of morbidity and mortality in monochorionic pregnancies. CASE REPORTS: We present two pairs of twins one of which we have followed for more than 6 years. The donors suffer from cerebral palsy, orofacial, and motor problems, and both are significantly smaller than their recipient twins. Interestingly, cranial MRI revealed medial frontal lobe polymicrogyria, ventriculomegaly, and decreased thickness in both parietal lobes in both donors. We suggest this as a possible feature of fetofetal transfusion syndrome. REVIEW: A minireview of the literature on neuroimaging and neurodevelopmental outcome in fetofetal transfusion syndrome is presented. CONCLUSION: While the close resemblance of the imaging features of both cases is likely incidental further study of a connection between migration and gyration disorders and fetofetal transfusion syndrome is warranted.

Diffusion profiling of tumor volumes using a histogram approach can predict proliferation and further microarchitectural features in medulloblastoma.

BACKGROUND: Medulloblastomas are the most common central nervous system tumors in childhood. Treatment and prognosis strongly depend on histology and transcriptomic profiling. However, the proliferative potential also has prognostical value. Our study aimed to investigate correlations between histogram profiling of diffusion-weighted images and further microarchitectural features. MATERIAL AND METHODS: Seven patients (age median 14.6 years, minimum 2 years, maximum 20 years; 5 male, 2 female) were included in this retrospective study. Using a Matlab-based analysis tool, histogram analysis of whole apparent diffusion coefficient (ADC) volumes was performed. RESULTS: ADC entropy revealed a strong inverse correlation with the expression of the proliferation marker Ki67 (r = - 0.962, p = 0.009) and with total nuclear area (r = - 0.888, p = 0.044). Furthermore, ADC percentiles, most of all ADCp90, showed significant correlations with Ki67 expression (r = 0.902, p = 0.036). DISCUSSION AND CONCLUSION: Diffusion histogram profiling of medulloblastomas provides valuable in vivo information which potentially can be used for risk stratification and prognostication. First of all, entropy revealed to be the most promising imaging biomarker. However, further studies are warranted.

Disseminated oligodendroglial-like leptomeningeal tumors: preliminary diagnostic and therapeutic results for a novel tumor entity [corrected].

Pediatric tumors of the central nervous system composed of oligoid tumor cells showing diffuse leptomeningeal spread without a primary mass lesion seem to represent a novel tumor entity. The terms "diffuse leptomeningeal glioneural tumor" or-preferably-"disseminated oligodendroglial-like leptomeningeal tumor of childhood" (DOGLT) were proposed. Four patients were identified with clinico-neuropathologic findings compatible with DOGLT and a mean follow-up time of 54 months was determined. Seven different biopsies obtained from the four patients were histologically evaluated. Clinical course, diagnostic measures, histopathologic and radiologic features and treatment suggestions were recorded, on the basis of which diagnostic and therapeutic algorithm was proposed. Patients with DOGLT presented with hydrocephalus as first symptom, requiring neurosurgical therapy. Open arachnoid biopsy was necessary to confirm diagnosis. The oligoid cells in a desmoplastic or focally myxoid matrix showed OLIG2-, MAP2-, S-100 and rare HuC/HuD protein-immunopositivity. IDH1 (R132H)- and CD99-immunohistochemistry was negative in all patients. None of the evaluable biopsies of three patients showed chromosome 1p/19q deletion, neither as isolated nor combined allelic loss. Chemotherapy according to the SIOP-LGG 2004 standard induction and consolidation protocol resulted in complete response and partial response, respectively, in 50 % of the patients. However, after discontinuation of chemotherapy, two patients experienced tumor progression and one of them succumbed to the disease after 19 months. Radiological criteria as well as preliminary treatment results are presented after observation of four clinical cases. Prognosis and long-term clinical courses remain to be observed.

Retroclival arachnoid cyst in a preterm infant after ventriculitis and intraventricular hemorrhage-a case report.

DISCUSSION: We present a case of a preterm boy of 29 gestational weeks with complicated posthemorrhagic hydrocephalus who developed a retroclival cyst extending to the upper cervical spinal canal and leading to brainstem compression. At the age of 2 months, third ventriculocisternocystostomy (ETVCC) resulted in temporary relief but was followed by reclosure of the stoma within weeks. At the age of 4 months, navigated endoscopic ventriculocisternocystostomy and endoscopy-guided stent catheter placement was performed with connection to a ventriculoperitoneal (VP) shunt system through a burr hole reservoir. CONCLUSION: This strategy improved the multiloculated hydrocephalus by establishing a communication between theretroclival subarachnoid cyst and the ventricular system, leading to uneventful further development of the child.

Integrated PET/MRI for planning navigated biopsies in pediatric brain tumors.

INTRODUCTION: An integrated PET/MRI scanner has been used in selected cases of pediatric brain tumor patients to obtain additional metabolic information about lesions for preoperative biopsy planning and navigation. PATIENTS AND METHODS: Four patients, age 9-16 years, received PET/MRI scans employing [(11)C]methionine positron emission tomography (PET) and contrast-enhanced 3D-MR sequences for neuronavigation. PET and MR sequences have been matched for neurosurgical guidance. An infrared camera-based neuronavigation system was employed with co-registered MR and PET images fused to hybrid images for preoperative planning, stereotactic biopsy planning, and/or intraoperative guidance. RESULTS: All patients showed hot spots of increased amino acid transport in PET and contrast-enhancing lesions in MRI. In three of the four patients, PET hot spots were congruent with contrast-enhancing areas in MRI. In two patients, frame-based stereotactic biopsies were taken from thalamo-mesencephalic lesions. One patient underwent second-look surgery for the suspicion of recurrent malignant glioma of the posterior fossa. One incidental frontal mass lesion was subtotally resected. No complications occurred. Hybrid imaging was helpful during the procedures to obtain representative histopathologic specimens and for surgical guidance during resection. Co-registered images did match with intraoperative landmarks, tumor borders, and histopathologic specimens. CONCLUSION: The integrated PET/MRI scanner offers co-registered multimodal, high-resolution data for neuronavigation with reduced radiation exposure compared to PET/CT scans. One examination session provides all necessary data for neuronavigation and preoperative planning, avoiding additional anesthesia in the small patients. Hybrid multimodality imaging may improve safety and yield additional information when obtaining representative histopathologic specimens of brain tumors.