[en] Diffusion-weighted magnetic resonance imaging (DWI) provides functional information and can be used for the detection and characterization of pathologic processes, including malignant tumors. The recently introduced concept of ''diffusion-weighted whole-body imaging with background body signal suppression'' (DWIBS) now allows acquisition of volumetric diffusion-weighted images of the entire body. This new concept has unique features different from conventional DWI and may play an important role in whole-body oncological imaging. This review describes and illustrates the basics of DWI, the features of DWIBS, and its potential applications in oncology. (orig.)

[en] Flattening of the epiphyses of long bones is seen in several skeletal dysplasias and standardized measurements on a radiograph of the knee to detect skeletal dysplasias using this feature have been described. Since then only two other studies in which this method was used have been published, and both included only a small number of children and neither had a control group. In addition, the Dutch National Working Group on Skeletal Dysplasias began to have doubts about the reliability of the method. We therefore decided to re-evaluate its accuracy in a population of children with and without a skeletal dysplasia. To determine the diagnostic value of standardized measurements on conventional AP radiographs of the knee in children with a skeletal dysplasia. Subjects and methods: We measured the distal femoral metaphysis and epiphysis according to the published method on conventional AP radiographs of the knee in 45 healthy children and 52 children with a skeletal dysplasia. We compared graphically the height of the distal femoral epiphysis with its width and with the width of the femoral metaphysis. Receiver operating characteristic (ROC) curves were calculated for each group of children. All graphs showed a considerable overlap between children with a skeletal dysplasia and healthy children. The size of the area under the ROC curves for the different groups was small, varying between 0.567 and 0.653. This method does not discriminate between children with a skeletal dysplasia and healthy children. We therefore consider it to be of little diagnostic value. (orig.)

[en] CT is currently the mainstay in staging malignant lymphoma in children, but the risk of second neoplasms due to ionizing radiation associated with CT is not negligible. Whole-body MRI techniques and whole-body diffusion-weighted imaging (DWI) in particular, may be a good radiation-free alternative to CT. DWI is characterized by high sensitivity for the detection of lesions and allows quantitative assessment of diffusion that may aid in the evaluation of malignant lymphomas. This article will review whole-body MRI techniques for staging malignant lymphoma with emphasis on whole-body DWI. Furthermore, future considerations and challenges in whole-body DWI will be discussed. (orig.)

[en] Imaging plays a major role in the diagnostic work-up of children with hepatobiliary or pancreatic diseases. It consists mainly of US, CT and MRI, with US and MRI being the preferred imaging modalities because of the lack of ionizing radiation. In this review the technique of US, CT and MRI in children will be addressed, followed by a comprehensive overview of the imaging characteristics of several hepatobiliary and pancreatic disease entities most common in the paediatric age group. (orig.)

[en] Purpose: Apparent diffusion coefficient (ADC) measurements in diffusion-weighted magnetic resonance imaging (DWI) may be of value in discriminating malignant from non-malignant lymph nodes, provided that they are reproducible. The aim of this study was to determine the inter- and intra-observer reproducibilities of ADC measurements of lymph nodes and to provide an overview of the current literature on ADC measurements in the characterization of lymph nodes. Materials and methods: Twenty healthy volunteers underwent DWI of the head and neck region and the pelvic region, at b-values of 0 and 1000 s/mm². Two observers independently and blindly measured ADCs of lymph nodes. Inter- and intra-observer reproducibilities were assessed using the Bland-Altman method. Results: Mean ADCs of normal lymph nodes (in 10^-3 mm²/s) varied between 1.15 and 1.18. Ranges of mean ADC difference ± limits of agreement (in 10^-3 mm²/s) for inter-observer agreement were -0.03 to 0.02 ± 0.15 to 0.31. Ranges of mean ADC difference ± limits of agreement (in 10^-3 mm²/s) for intra-observer agreement were 0.00 to 0.04 ± 0.13 to 0.32. Conclusion: In conclusion, in light of previously reported data, the results of the present study suggest that ADC measurements may not always be sufficiently reproducible to discriminate malignant from non-malignant lymph nodes. Future studies which directly compare the ADCs of different nodal pathologies/conditions are required to further investigate the inter- and intra-observer reproducibilities of ADC measurements of lymph nodes.

[en] The recent technical development of multidetector CT (MDCT) has contributed to a substantial increase in its diagnostic applications and accuracy in children. A major drawback of MDCT is the use of ionising radiation with the risk of inducing secondary cancer. Therefore, justification and optimisation of paediatric MDCT is of great importance in order to minimise these risks (''as low as reasonably achievable'' principle). This review will focus on all technical and non-technical aspects relevant for paediatric MDCT optimisation and includes guidelines for radiation dose level-based CT protocols. (orig.)

[en] Purpose: Incidental extracolonic findings affect patient treatment and cost. Therefore, to consider magnetic resonance colonography (MRC) as a tool for colorectal cancer and polyps screening, more knowledge is needed on extracolonic findings. In this study, we sought to determine the prevalence and the spectrum of extracolonic findings in patients with an increased risk colorectal cancer that underwent bright lumen MRC. Materials and methods: MRC examinations were performed in 210 patients. A gadolinium solution was administered rectally for distension of the colon. Extracolonic findings were scored by two radiologists and classified by using C-RADS Reporting System. All findings (with advice regarding work-up) were reported to the patient's physician and followed up for 4.5 years on average. Results: Extracolonic findings were found in 125 (59.5%) patients. Ten (4.8%) had 'potentially important' findings (C-RADS category E4). Twenty-five patients (11.9%) had 'likely unimportant' findings (E3), 90 (42.8%) had 'clinically unimportant' findings (E2) and 85 (40.5%) had a normal exam (E1). In 14 (6.7%) patients additional work-up was performed for their incidentally discovered lesions. In three of them surgery was performed. After work-up, only in two (1.0%) patients a malignancy was found. Conclusion: The number of new relevant extracolonic findings is small and the required additional work-up is limited. This should be considered for implementation of 'bright lumen' MRC as a screening tool.

[en] Normative data on pulmonary nodules in children without malignancy are limited. Knowledge of the frequency and characteristics of pulmonary nodules in healthy children can influence care decisions in children with malignant disease. To provide normative data concerning the frequency and characteristics of pulmonary nodules on computed tomography (CT) in young children. All children ages 1 year-12 years who underwent chest CT after high-energy trauma were retrospectively investigated. Exclusion criteria were a history of malignancy, thick image slices, motion artefacts and extensive post-traumatic pulmonary changes. Two radiologists were asked to independently identify all nodules and to characterize each nodule with respect to location, size, perifissural location and calcification. Discrepancies were adjudicated by a third reader, who set the reference standard in this study. Interobserver agreement in detection and characterization was assessed using the kappa coefficient (κ). Identified were 120 patients, of whom 72 (75% male; median age: 8.0 years [interquartile range: 4-11]) were included. A total of 59 pulmonary nodules were present in 27 patients (38%; 95% confidence interval: 26-49%; range: 1-5 nodules per patient, with a mean diameter of 3.2 mm [standard deviation: 0.9 mm]). For nodule detection, the per-patient interobserver agreement was substantial (κ=0.78) and per-lobe agreement was moderate (κ=0.40). For characterization, there was fair to substantial agreement (κ=0.36-0.74). Small pulmonary nodules on chest CT are a common finding in otherwise healthy children, but detection and characterization have only moderate interobserver agreement. (orig.)

[en] To systematically review and meta-analyse published data on the diagnostic performance of ¹⁸F-FDG PET/CT in detecting bone marrow involvement in patients with newly diagnosed diffuse large B-cell lymphoma (DLBCL). PubMed/MEDLINE and Embase were systematically searched for relevant studies. The methodological quality of each study was assessed. Sensitivities and specificities of FDG PET/CT in individual studies were calculated and meta-analysed with a random effects model. A summary receiver operating characteristic curve (sROC) was constructed with the Moses-Shapiro-Littenberg method. Weighted summary proportions of discrepancies between the FDG PET/CT and (blind) bone marrow biopsy (BMB) results among all patients were calculated. Seven studies, with a total of 654 patients with newly diagnosed DLBCL, were included. Overall, the quality of the included studies was moderate. The sensitivity and specificity of FDG PET/CT for detecting bone marrow involvement ranged from 70.8 % to 95.8 % and from 99.0 % to 100 %, with pooled estimates of 88.7 % (95 % confidence interval, CI, 82.5 - 93.3 %) and 99.8 % (95 % CI 98.8 - 100 %), respectively. The area under the sROC curve was 0.9983. The weighted summary proportion of FDG PET/CT-negative patients with positive BMB findings among all patients was 3.1 % (95 % CI 1.8 - 5.0 %) and the weighted summary proportion of FDG PET/CT-positive patients with negative BMB findings among all patients was 12.5 % (95 % CI 8.4 - 17.3 %). FDG PET/CT is accurate and complementary to BMB for detecting bone marrow involvement in patients with newly diagnosed DLBCL. A negative FDG PET/CT scan cannot rule out the presence of bone marrow involvement, but positive FDG PET/CT findings obviate the need for BMB for the detection of bone marrow involvement in these patients. (orig.)

[en] Lymph node enlargement is commonly used to indicate abnormality. To evaluate the normal size and prevalence of abdominal lymph nodes in children at CT. In this retrospective study, we included a total of 152 children ages 1–17 years who underwent abdominal CT examination after high-energy trauma. We measured abdominal lymph nodes in five lymph node stations (inguinal, iliac, para-aortic, hepatic and mesenteric). For the largest lymph node in each level, we measured long- and short-axis diameters in both the axial and coronal planes. We then calculated distribution parameters, correlation coefficients between lymph node size and age, and reference intervals. The prevalence of detectable lymph nodes was high for the inguinal (100%), iliac (98%), para-aortic (97%) and mesenteric (99%) stations and lower for the hepatic station (32%). Lymph node size showed small to medium significant correlations (ranging from 0.21 to 0.50) with age. When applying the Lugano criteria and RECIST (Response Criteria in Solid Tumors), 29 children (19%) would have had one or more enlarged abdominal lymph nodes. The results of this study provide normative data of abdominal lymph node size in children. The current adult guidelines for enlarged lymph nodes seem adequate for most children with the exception of young adolescents, in which larger lymph nodes were relatively common, particularly in the inguinal region.