[(Uro)genital developmental disorders]. / (Uro)genitale Entwicklungsstörungen.

CLINICAL ISSUE: Congenital anomalies of the urogenital tract are common, whereas isolated developmental disorders of the genital organs are rare and varied. The type and timing of imaging to characterize these developmental disorders and the planning of any treatment are the subject of discussion. The aim of this article is to provide a brief overview of embryology, diagnostic procedures, and examples of findings. STANDARD RADIOLOGICAL METHODS: The primary procedure for imaging the genitals is sonography, which must be performed with appropriate empathy. In addition to the genitals, the general situation of the kidneys and urinary tract should be examined, as urogenital malformations are often combined. Dedicated magnetic resonance imaging (MRI) is indicated as advanced imaging in interdisciplinary consultations. Invasive procedures, such as genitography combined with micturition cystourethrography (MCU) using X­rays or contrast-enhanced sonography, are rarely required. Computed tomography (CT) or excretory urography play no role. CONCLUSION: Imaging plays an important role in the assessment of genital anomalies. Knowledge of embryology facilitates anatomical understanding and the assessment of pathologies.

Update on imaging recommendations in paediatric uroradiology: the European Society of Paediatric Radiology workgroup session on voiding cystourethrography.

Voiding cystourethrography (VCUG) is a fluoroscopic technique that allows the assessment of the urinary tract, including the urethra, bladder, and-if vesicoureteral reflux (VUR) is present-the ureters and the pelvicalyceal systems. The technique also allows for the assessment of bladder filling and emptying, providing information on anatomical and functional aspects. VCUG is, together with contrast-enhanced voiding urosonography (VUS), still the gold standard test to diagnose VUR and it is one of the most performed fluoroscopic examinations in pediatric radiology departments. VCUG is also considered a follow-up examination after urinary tract surgery, and one of the most sensitive techniques for studying anatomy of the lower genitourinary tract in suspected anatomical malformations. The international reflux study in 1985 published the first reflux-protocol and graded VUR into five classes; over the following years, other papers have been published on this topic. In 2008, the European Society of Paediatric Radiology (ESPR) Uroradiology Task Force published the first proposed VCUG Guidelines with internal scientific society agreement. The purpose of our work is to create a detailed overview of VCUG indications, procedural recommendations, and to provide a structured final report, with the aim of updating the 2008 VCUG paper proposed by the European Society of Paediatric Radiology (ESPR). We have also compared VCUG with contrast-enhanced VUS as an emergent alternative. As a result of this work, the ESPR Urogenital Task Force strongly recommends the use of contrast-enhanced VUS as a non-radiating imaging technique whenever indicated and possible.

[CF Lung Disease - a German S3 Guideline: Pseudomonas aeruginosa]. / S3-Leitlinie: Lungenerkrankung bei Mukoviszidose ­ Pseudomonas aeruginosa.

Cystic Fibrosis (CF) is the most common autosomal recessive genetic multisystemic disease. In Germany, it affects at least 8000 people. The disease is caused by mutations in the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) gene leading to dysfunction of CFTR, a transmembrane chloride channel. This defect causes insufficient hydration of the airway epithelial lining fluid which leads to reduction of the mucociliary clearance.Even if highly effective, CFTR modulator therapy has been available for some years and people with CF are getting much older than before, recurrent and chronic infections of the airways as well as pulmonary exacerbations still occur. In adult CF life, Pseudomonas aeruginosa (PA) is the most relevant pathogen in colonisation and chronic infection of the lung, leading to further loss of lung function. There are many possibilities to treat PA-infection.This is a S3-clinical guideline which implements a definition for chronic PA-infection and demonstrates evidence-based diagnostic methods and medical treatment in order to give guidance for individual treatment options.

[Imaging after kidney transplantation in childhood and adolescence]. / Bildgebung nach Nierentransplantation im Kindes- und Jugendalter.

The ultrasound (US) examination is the most important imaging procedure in the clinical care of children with chronic kidney disease, the assessment before kidney transplantation and in the acute and chronic phase after successful kidney transplantation. In trained hands, particularly with experience in Doppler sonography, US ensures that vascular complications, such as occlusions, thrombosis, stenosis as well as non-vascular complications, e.g., urinary tract dilatation, abscesses, hematomas, urine leaks or lymphoceles, are cost-effectively and rapidly diagnosed at any time. For the diagnosis of acute rejection, the US signs in the intraindividual course are only suggestive, but not specific. The gold standard for the diagnosis of acute rejection is a kidney biopsy. In these cases, US serves to exclude other causes. The use of multimodal techniques, various Doppler techniques and microvascular procedures, such as superb microvascular imaging (SMI) or B­flow and contrast-enhanced ultrasonography (CEUS), optimizes the imaging in the context of transplantations in children. Magnetic resonance imaging with diffusion-weighed imaging (DWI), magnetic resonance angiography (MRA) and magnetic resonance urography (MRU) as well as functional MRU (fMRU) performed with the administration of gadolinium-containing contrast agents, are part of the extended diagnostics and possibly necessary for surgical planning in the early phase after kidney transplantation and for long-term assessment after transplantation. Excretory urography is associated with ionizing radiation and intravenous administration of iodine-containing contrast medium and is obsolete in children. Computed tomography (CT) using age-adapted and weight-adapted dose protocols is an alternative in emergencies if MRI is not available.

Forensic Diagnostics of the Skeletal Age in the Living - Backgrounds and Methodology. / Forensische Diagnostik des Skelettalters bei Lebenden ­ Hintergründe und Methodik.

BACKGROUND: The expert opinions on forensic age diagnostics requested by state institutions are used to show the exceeding of legally relevant age thresholds, especially the completed 18th year of life. According to the recommendations of the Study Group on Forensic Age Diagnostics (AGFAD), this requires - among other things - a determination of skeletal age. METHOD: Considering recent scientific knowledge, the current conditions and established skeletal age diagnostics methods are presented. Additionally, this review article sheds light on the influence of ethnicity and socioeconomic status, questions regarding indication, as well as alternative and future developments. RESULTS AND CONCLUSION: In forensic age diagnostics, particularly hand radiography and thin-slice CT of the medial clavicular epiphysis are relevant for determining skeletal age. The Atlas method of Greulich and Pyle (1959) and the clavicular stages by Schmeling et al. (2004) and Kellinghaus et al. (2010) are primarily used for this. This spectrum of methods, which is based on a very solid database, might be supplemented by MRI studies of the knee joint in the near future. KEY POINTS: · Determining skeletal age is an essential part of forensic age diagnostics commissioned by state authorities and courts.. · Hand radiography and CT of the medial clavicular epiphysis form the core of the spectrum of methods recommended by the Study Group of Forensic Age Diagnostics (AGFAD).. · Since the radiological studies required for forensic age diagnostics are not medically indicated, it must be ensured that the legal basis is specifically named in each case when commissioning expert opinions.. · MRI studies of the knee joint might increase the spectrum of methods in the near future.. CITATION FORMAT: · Wittschieber D, Hahnemann ML, Mentzel H. Forensic Diagnostics of the Skeletal Age in the Living - Backgrounds and Methodology. Fortschr Röntgenstr 2024; 196: 254 - 261.

[Congenital anomalies of the kidneys and urinary tract (CAKUT) : Embryology in radiology and fetal magnetic resonance imaging]. / Angeborene Anomalien der Nieren und ableitenden Harnwege (CAKUT) : Embryologie in der Radiologie und fetale Magnetresonanztomographie.

CLINICAL PROBLEM: Congenital anomalies of the kidney and urinary tract (CAKUT) are very common findings in fetal diagnostics. Their effects range from variants without pathological significance to pronounced functional impairment with the need for renal replacement therapy in childhood. Sometimes the genital organs are also affected. The aim of the article is to provide an overview of embryology and examples of key findings. IMAGING PROCEDURES: In the fetal period, magnetic resonance imaging (MRI) is used, while postnatally, sonography with the option of contrast-enhanced micturition urosonography (MUS, ceVUS) dominates imaging in pediatric radiology, supplemented in individual cases by fluoroscopy (micturition cysturethrography) and MRI. Quantitative methods for assessing kidney function and excretion (MAG3 scintigraphy, functional MR urography) are essential when planning further therapeutic procedures, especially in obstructive uropathies. CONCLUSION: Imaging plays an essential role in the assessment of abnormalities of the kidneys and urinary tract both pre- and postnatally. Knowledge of embryology facilitates anatomical understanding and assessment of pathologies.

Biallelic NUDT2 variants defective in mRNA decapping cause a neurodevelopmental disease.

Dysfunctional RNA processing caused by genetic defects in RNA processing enzymes has a profound impact on the nervous system, resulting in neurodevelopmental conditions. We characterized a recessive neurological disorder in 18 children and young adults from 10 independent families typified by intellectual disability, motor developmental delay and gait disturbance. In some patients peripheral neuropathy, corpus callosum abnormalities and progressive basal ganglia deposits were present. The disorder is associated with rare variants in NUDT2, a mRNA decapping and Ap4A hydrolysing enzyme, including novel missense and in-frame deletion variants. We show that these NUDT2 variants lead to a marked loss of enzymatic activity, strongly implicating loss of NUDT2 function as the cause of the disorder. NUDT2-deficient patient fibroblasts exhibit a markedly altered transcriptome, accompanied by changes in mRNA half-life and stability. Amongst the most up-regulated mRNAs in NUDT2-deficient cells, we identified host response and interferon-responsive genes. Importantly, add-back experiments using an Ap4A hydrolase defective in mRNA decapping highlighted loss of NUDT2 decapping as the activity implicated in altered mRNA homeostasis. Our results confirm that reduction or loss of NUDT2 hydrolase activity is associated with a neurological disease, highlighting the importance of a physiologically balanced mRNA processing machinery for neuronal development and homeostasis.

[Hip dysplasia]. / Hüftdysplasie.

BACKGROUND: Hip dysplasia is one of the most common malformations in childhood and has a significant impact on the further life of those affected. A distinction must be made between congenital and the much rarer acquired dysplasia. Early diagnosis and therapy are pivotal for further development of patients. OBJECTIVES: The paper gives an overview of current radiological possibilities of diagnosis with focus on congenital hip dysplasia supplemented by insights into therapeutic options. MATERIALS AND METHODS: Basic and review papers were analyzed. RESULTS: Clinical examination of the newborn has low sensitivity and specificity in the diagnosis of hip dysplasia. The introduction of Graf ultrasound screening has significantly improved the early detection of dysplastic hips. With the help of sonography, but also magnetic resonance imaging (MRI), the shape of the acetabulum and the position of the femoral head in the socket can be precisely and quickly determined, while X­ray examinations have their place especially in the context of follow-up examinations after treatment from the age of 1 year and in the diagnosis of secondary dysplasia. Therapeutic options range from spreading treatment to open reduction with fixation in the newborn as well as conversion osteotomy in older children. CONCLUSION: Early detection of hip dysplasia is critical to the course of treatment. The right choice of examination method and correct performance are essential for further treatment.

Functional MR urography in children - update 2023. / Funktionelle MR-Urografie im Kindesalter ­ Update 2023.

BACKGROUND: Functional MR urography (fMRU) has developed into an innovative, radiation-free option for assessing parameters of kidney function in pediatric radiology. The importance of fMRU in comparison to the standardized established nuclear medicine procedure (99mTc-Mercapto-acetyltriglycerine, MAG3 scintigraphy) is shown using SWOT analysis. METHODS: To assess the current state of research, a selective literature search was carried out in PubMed. Taking into account the current scientific status, the examination technique, preparation, and evaluation of fMRU are presented. RESULTS: As a result of the comparison with MAG3, fMRU is suitable for certain indications and represents an optimal combination of morphological and functional representation of the kidneys and urinary tract, especially in the case of surgical consequences. CONCLUSION: fMRU has been successfully established as a diagnostic method for assessing the morphology and function of the kidneys in competition with MAG3 scintigraphy. KEY POINTS: · Functional MRU allows reliable statements on the morphology and function of the kidneys and urinary tract.. · The results of the functional assessment of fMRU are comparable to the results of MAG3 scintigraphy.. · The complex implementation and demanding evaluation limits the spread of fMRU as a complete alternative to MAG3 scintigraphy. fMRU is reserved for special indications.. · Functional MRU has prevailed over MAG3 scintigraphy for complex renal and urinary tract anomalies (CAKUT) that require surgical correction. An example is the clarification of dribbling in girls, which is usually based on an ectopic opening of a ureter in a double system.. CITATION FORMAT: · Kirsch H, Krüger P, John-Kroegel U et al. Functional MR urography in children - update 2023. Fortschr Röntgenstr 2023; 195: 1097 - 1105.

Amniotic fluid content in children with kidney and urinary tract anomalies determines pre- and postnatal development.

BACKGROUND: Renal oligohydramnios (ROH) describes an abnormally low volume of amniotic fluid (AF) during pregnancy. ROH is mostly caused by congenital fetal kidney anomalies. The ROH diagnosis frequently implies an increased risk of peri- and postnatal fetal mortality and morbidity. The present study aimed to evaluate the impact of ROH on pre-and postnatal development in children with congenital kidney anomalies. METHODS: This retrospective study included 168 fetuses with anomalies in the kidney and urinary tract. Based on the amount of AF measured by ultrasound, patients were divided into three groups: normal amniotic fluid (NAF), amniotic fluid in the lower normal range (LAF), and ROH. These groups were compared with respect to prenatal sonographic parameters, perinatal outcomes, and postnatal outcomes. RESULTS: Among the 168 patients with congenital kidney anomalies, 26 (15%) had ROH, 132 (79%) had NAF, and 10 (6%) had LAF. Of the 26 families affected by ROH, 14 (54%) decided to terminate pregnancy. Of 10 live-born children in the ROH group, 6 (60%) survived the observation time; of these, 5/6 presented with chronic kidney disease, stages I-III, at their last examination. The main differences in postnatal development between the ROH group and the NAF and LAF groups were: restricted height and weight gain, respiratory issues, complicated feeding, and the presence of extrarenal malformations. CONCLUSIONS: ROH is not a mandatory indicator of severe postnatal kidney function impairment. However, children with ROH have complicated peri-and postnatal periods, due to the presence of concomitant malformations, which must be considered in prenatal care. A higher resolution version of the Graphical abstract is available as Supplementary information.

Radiation Exposure and Frequency of Dental, Bitewing and Occlusal Radiographs in Children and Adolescents.

Dental radiographs are valuable diagnostic aids for oral healthcare, but exposure to ionizing radiation carries health risks, especially in children due to their high radio-sensitivity. Valid reference values for intraoral radiographs in children and adolescents are still missing. This study aimed to investigate the radiation dose values and underlying justifications of dental, bitewing and occlusal X-rays in children and adolescents. Data from routinely executed intraoral radiographs between 2002 and 2020 with conventional and digital tube-heads were extracted from the Radiology Information System. The effective exposure was calculated from technical parameters and statistical tests performed. A total number of 4455 intraoral (3128 dental, 903 bitewing and 424 occlusal) radiographs were investigated. For dental and bitewing radiographs, the dose area product (DAP) was 2.57 cGy × cm2 and the effective dose (ED) 0.77 µSv. For occlusal radiographs, the DAP was 7.43 cGy × cm2 and the ED 2.22 µSv. Overall, 70.2% of all intraoral radiographs were dental, 20.3% bitewing and 9.5% occlusal radiographs. The most frequent indication for intraoral radiographs was trauma (28.7%), followed by caries (22.7%) and apical diagnostics (22.7%). Moreover, 59.7% of all intraoral radiographs were taken in boys, especially for trauma (66.5%) and endodontics (67.2%) (p ≤ 0.00). Girls were significantly more frequently X-rayed for caries diagnostics than boys (28.1% vs. 19.1%, p ≤ 0.00). The average ED of 0.77 µSv for intraoral dental and bitewing radiographs in this study was within the range of other reported values. The technical parameters of the X-ray devices were found at the lowest recommended levels to best limit the radiation exposure and to assure acceptable diagnostic efficacy. Intraoral radiographs were performed predominantly for trauma, caries and apical diagnostics-reflecting general recommendations for the use of X-rays in children. For improved quality assurance and radiation protection, further studies are necessary to determine the meaningful dose reference level (DRL) for children.

Lung ultrasound in children and adolescents with long-term effects of COVID-19: Initial results.

Introduction: Chronic health effects following acute COVID-19 are increasingly observed as the pandemic continues and are grouped under long COVID. Although the acute course of the COVID disease is often milder, long COVID also affects children and adolescents. As the symptoms present in Long-COVID often seem to be non-specific and not limited to organ systems, clarification of the causes and the creation of a meaningful, efficient and targeted diagnostic algorithm is urgently needed. Methods: Therefore, in this prospective observational study, we examined 30 children with long COVID using lung ultrasound and compared the results with those of 15 lung-healthy children. Results: In our study, no significant difference was found between the two groups in the morphological criteria of lung ultrasound of the pleura or pleural lung structures. There was no significant correlation between the lung ultrasound findings and clinical Data. Discussion: Our findings are congruent with the current, albeit sparse, data. It is possible that the causes of persistent thoracic symptoms in long COVID might be more likely to be present in functional examinations, but not morphologically imageable. Nonspecific symptoms do not appear to be due to changes in the lung parenchyma. In conclusion, lung ultrasound alone and without baseline in acute disease is not suitable as a standard in the follow-up of long COVID patients. Further investigations on the morphological and functional changes in patient with long COVID is needed.

Pediatric computed tomography doses in Germany from 2016 to 2018 based on large-scale data collection.

PURPOSE: Accumulating evidence from epidemiological studies that pediatric computed tomography (CT) examinations can be associated with a small but non-zero excess risk for developing leukemia or brain tumor highlights the need to optimize doses of pediatric CT procedures. Mandatory dose reference levels (DRL) can support reduction of collective dose from CT imaging. Regular surveys of applied dose-related parameters are instrumental to decide when technological advances and optimized protocol design allow lower doses without sacrificing image quality. Our aim was to collect dosimetric data to support adapting current DRL to changing clinical practice. METHOD: Dosimetric data and technical scan parameters from common pediatric CT examinations were retrospectively collected directly from Picture Archiving and Communication Systems (PACS), Dose Management Systems (DMS), and Radiological Information Systems (RIS). RESULTS: We collected data from 17 institutions on 7746 CT series from the years 2016 to 2018 from examinations of the head, thorax, abdomen, cervical spine, temporal bone, paranasal sinuses and knee in patients below 18 years of age. Most of the age-stratified parameter distributions were lower than distributions from previously-analyzed data from before 2010. Most of the third quartiles were lower than German DRL at the time of the survey. CONCLUSIONS: Directly interfacing PACS, DMS, and RIS installations allows large-scale data collection but relies on high data-quality at the documentation stage. Data should be validated by expert knowledge or guided questionnaires. Observed clinical practice in pediatric CT imaging suggests lowering some DRL in Germany is reasonable.

Whole-body diffusion magnetic resonance imaging with simultaneous multi-slice excitation in children and adolescents.

BACKGROUND: Whole-body magnetic resonance imaging (WB-MRI) is an increasingly used guideline-based imaging modality for oncological and non-oncological pathologies during childhood and adolescence. While diffusion-weighted imaging (DWI), a part of WB-MRI, enhances image interpretation and improves sensitivity, it also requires the longest acquisition time during a typical WB-MRI scan protocol. Interleaved short tau inversion recovery (STIR) DWI with simultaneous multi-slice (SMS) acquisition is an effective way to speed up examinations. OBJECTIVE: In this study of children and adolescents, we compared the acquisition time, image quality, signal-to-noise ratio (SNR) and apparent diffusion coefficient (ADC) values of an interleaved STIR SMS-DWI sequence with a standard non-accelerated DWI sequence for WB-MRI. MATERIALS AND METHODS: Twenty children and adolescents (mean age: 13.9 years) who received two WB-MRI scans at a maximum interval of 18 months, consisting of either standard DWI or SMS-DWI MRI, respectively, were included. For quantitative evaluation, the signal-to-noise ratio (SNR) was determined for b800 images and ADC maps of seven anatomical regions. Image quality evaluation was independently performed by two experienced paediatric radiologists using a 5-point Likert scale. The measurement time per slice stack, pause between measurements including shim and total measurement time of DWI for standard DWI and SMS-DWI were extracted directly from the scan data. RESULTS: When including the shim duration, the acquisition time for SMS-DWI was 43% faster than for standard DWI. Qualitatively, the scores of SMS-DWI were higher in six locations in the b800 images and four locations in the ADC maps. There was substantial agreement between both readers, with a Cohen's kappa of 0.75. Quantitatively, the SNR in the b800 images and the ADC maps did not differ significantly from one another. CONCLUSION: Whole body-MRI with SMS-DWI provided equivalent image quality and reduced the acquisition time almost by half compared to the standard WB-DWI protocol.

Frequency of Dental X-ray Diagnostics in Children and Adolescents: What Is the Radiation Exposure?

Children are exposed to ionizing radiation through radiographs during their development for various reasons. At present, there are no officially valid reference values for dental X-rays in children and adolescents for dental X-ray diagnostics. This study retrospectively examined 9680 extraoral dental radiographs in pediatric patients between 2002 and 2020. The aim was to analyze the radiation doses in pediatric patients, which indications were used, and whether there were specific age and gender differences. The evaluation showed that radiation doses were considered low, with dose area products of 2.2 cGy × cm2 for a lateral cephalogram, 14 cGy × cm2 for an orthopantomogram (OPG), and 45 cGy × cm2 for cone beam computer tomography (CBCT). This corresponds to an effective dose of 1.5 µSv for a lateral cephalogram, 7 µSv for an OPG, and 33.8 µSv for CBCT. Of the 9680 images, 78% were orthopantomograms, and only 0.4% were CBCT images. OPG has become more important over the years, as reflected in the indication. Approximately one-third of all extraoral exposures are orthodontic indications. Overall, the indications were similar for both genders. According to the dental indications, boys were X-rayed slightly more frequently than girls (54.5-45.5%). A future publication of dose guide values and corresponding guidelines is of high priority.

[Radiological methods for age diagnostics : Clinical and forensic aspects]. / Radiologische Methoden zur Altersdiagnostik : Klinische und forensische Aspekte.

Age diagnostics play an increasing role in radiology. Medical and forensic questions are indications for the application of age diagnostics. In addition to X­rays of the hand in childhood, panoramic tomography and computed tomography are currently the standard procedures. Alternative modalities without ionizing radiation (sonography, magnetic resonance imaging) have not (yet) been established. The purpose of this article is to present the indications and methods of age diagnostics in the clinical and forensic contexts and to familiarize you with their advantages and disadvantages as well as the possibility of determining the final length.

Ultrasound findings of the thyroid gland in children and adolescents.

Ultrasonography (US) is an important diagnostic tool in evaluating thyroid diseases in pediatric patients. This pictorial essay reviews the application of various ultrasound techniques such as B-Mode ultrasound and color Doppler, elastography and contrast enhanced ultrasound (CEUS) in children and adolescents in various thyroid pathologies including congenital thyroid abnormalities, diffuse thyroid diseases (DTD), focal thyroid lesions and thyroid malignancy.

The distal femoral epiphysis in forensic age diagnostics: studies on the evaluation of the ossification process by means of T1- and PD/T2-weighted magnetic resonance imaging.

The age of majority, which corresponds to the age of 18 years in most European countries, plays a crucial role for a large number of legal decisions. Accordingly, an increasing number of requests by authorities to forensic age estimation experts comprise the question of whether the age of 18 years has been reached by an individual. In recent years, novel study data suggested that magnetic resonance imaging (MRI) of the knee might likewise allow for the determination of majority beyond reasonable doubt. However, the data basis, especially concerning the distal femoral epiphysis (DFE), is still poor. For this reason, 392 routine MRI cases of the knee (204 males and 188 females of a Western Caucasian population, aged between 12 and 25 years) were retrospectively analyzed. T1-weighted and water-selective fat-saturated PD/T2-weighted sequences, generated at 1.5 and 3.0 T clinical MR scanners, were available. Ossification stages of the DFE were determined by means of the classification system by Vieth et al. (Eur Radiol 2018; 28:3255-3262). Both the intra-observer agreement and inter-observer agreement were found to be "very good" (κ = 0.899 and κ = 0.830). The present study confirmed that MRI of the DFE is suitable to determine majority in both sexes when stage 6 is present as the study revealed minimum ages above the age of 18 years for this stage (20.40 years in males and 20.60 years in females). Accordingly, the data represent a strong support for the so far existing database. Hence, the investigation of the knee using routine MRI appears to become a realistic alternative for forensic age estimation practice in the near future.

Characterization of subdural collections in initial neuroimaging of abusive head trauma: Implications for forensic age diagnostics and clinical decision-making.

PURPOSE: Subdural collections (SDCs) represent a key finding in abusive head trauma (AHT), a serious form of child physical abuse. Common SDC entities in this context are subdural hematoma (SDH), subdural hygroma (SDHy), subdural hematohygroma (SDHHy), and chronic subdural hematoma (cSDH). The present study examines the prevalence of the different SDC entities and investigates the influence of the SDC diagnosis on the forensic age estimation of the injury. METHODS: In this retrospective multi-center study from three German university hospitals of a 10-year period, the initial neuroimaging material (CT or MRI) of 56 children (36 males, 20 females; age median 3.9 months) with medico-legally well-documented AHT was analyzed. SDCs were characterized by determining presence, location, extension, and visual appearance, by assigning to one of the five entities, and by categorizing with three different classification systems, one of which represents a novel system based on focality and Mixed Appearance Pattern and especially developed for children with AHT. The data were correlated with demographic and clinical data. By means of court files, AHT cases were also sub-divided into confession (n = 14) and non-confession cases (n = 42) and then compared. RESULTS: Most cases showed a multifocal presence of SDCs (96.4%) and the presence of a Mixed Appearance Pattern (82.1%). The most common SDC entity was the heterogeneous variant of the SDHHy (66.1%). The cSDH occurred infrequently only (3.6%). Our novel classification system illustrates that unifocal SDCs rarely occur in AHT, and that more complex SDC patterns are common. In nearly all cases (94.6%), additional signs of recently caused brain injury were present beside the SDCs. Comparison between confession and non-confession groups did not reveal any significant differences, indicating that the diagnostic criteria of AHT are robust. CONCLUSIONS: Although precise dating of SDCs based on initial neuroimaging alone remains unrealistic, the exact diagnosis of the SDC entity provide an important basis for differentiation between acute trauma and chronic post-traumatic state. Therefore, especially the confirmation or exclusion of subdural neomembranes, that define the cSDH, should be considered indispensable.