MRI Characteristics of Pediatric Renal Tumors: A SIOP-RTSG Radiology Panel Delphi Study

BACKGROUND

The SIOP-Renal Tumor Study Group (RTSG) does not advocate invasive procedures to determine histology before the start of therapy. This may induce misdiagnosis-based treatment initiation, but only for a relatively small percentage of approximately 10% of non-Wilms tumors (non-WTs). MRI could be useful for reducing misdiagnosis, but there is no global consensus on differentiating characteristics.

PURPOSE

To identify MRI characteristics that may be used for discrimination of newly diagnosed pediatric renal tumors.

STUDY TYPE

Consensus process using a Delphi method.

POPULATION

Not applicable.

FIELD STRENGTH/SEQUENCE

Abdominal MRI including T1- and T2-weighted imaging, contrast-enhanced MRI, and diffusion-weighted imaging at 1.5 or 3 T.

ASSESSMENT

Twenty-three radiologists from the SIOP-RTSG radiology panel with ≥5 years of experience in MRI of pediatric renal tumors and/or who had assessed ≥50 MRI scans of pediatric renal tumors in the past 5 years identified potentially discriminatory characteristics in the first questionnaire. These characteristics were scored in the subsequent second round, consisting of 5-point Likert scales, ranking- and multiple choice questions.

STATISTICAL TESTS

The cut-off value for consensus and agreement among the majority was ≥75% and ≥60%, respectively, with a median of ≥4 on the Likert scale.

RESULTS

Consensus on specific characteristics mainly concerned the discrimination between WTs and non-WTs, and WTs and nephrogenic rest(s) (NR)/nephroblastomatosis. The presence of bilateral lesions (75.0%) and NR/nephroblastomatosis (65.0%) were MRI characteristics indicated as specific for the diagnosis of a WT, and 91.3% of the participants agreed that MRI is useful to distinguish NR/nephroblastomatosis from WT. Furthermore, all participants agreed that age influenced their prediction in the discrimination of pediatric renal tumors.

DATA CONCLUSION

Although the discrimination of pediatric renal tumors based on MRI remains challenging, this study identified some specific characteristics for tumor subtypes, based on the shared opinion of experts. These results may guide future validation studies and innovative efforts.

LEVEL OF EVIDENCE

3 Technical Efficacy Stage: 3.

Relapse of Wilms' tumour and detection methods: a retrospective analysis of the 2001 Renal Tumour Study Group-International Society of Paediatric Oncology Wilms' tumour protocol database

BACKGROUND

Wilms' tumour is the most common renal cancer in childhood and about 15% of patients will relapse. There is scarce evidence about optimal surveillance schedules and methods for detection of tumour relapse after therapy.

METHODS

The Renal Tumour Study Group-International Society of Paediatric Oncology (RTSG-SIOP) Wilms' tumour 2001 trial and study is an international, multicentre, prospective registration, biological study with an embedded randomised clinical trial for children with renal tumours aged between 6 months and 18 years. The study covers 243 different centres in 27 countries grouped into five consortia. The current protocol of SIOP surveillance for Wilms' tumour recommends that abdominal ultrasound and chest x-ray should be done every 3 months for the first 2 years after treatment and be repeated every 4-6 months in the third and fourth year and annually in the fifth year. In this retrospective cohort study of the protocol database, we analysed data from participating institutions on timing, anatomical site, and mode of detection of all first relapses of Wilms' tumour. The primary outcomes were how relapse of Wilms' tumour was detected (ie, at or between scheduled surveillance and with or without clinical symptoms, scan modality, and physical examination) and to estimate the number of scans needed to capture one subclinical relapse. The RTSG-SIOP study is registered with Eudra-CT, number 2007-004591-39.

FINDINGS

Between June 26, 2001, and May 8, 2015, of 4271 eligible patients in the 2001 RTSG-SIOP Wilms' tumour database, 538 (13%) relapsed. Median follow-up from surgery was 62 months (IQR 32-93). The method used to detect relapse was registered for 410 (76%) of 538 relapses. Planned surveillance imaging captured 289 (70%) of these 410 relapses. The primary imaging modality used to detect relapse was reported for 251 patients, among which relapse was identified by abdominal ultrasound (80 [32%] patients), chest x-ray (78 [31%]), CT scan of the chest (64 [25%]) or abdomen (20 [8%]), and abdominal MRI (nine [4%]). 279 (68%) of 410 relapses were not detectable by physical examination and 261 (64%) patients did not have clinical symptoms at relapse. The estimated number of scans needed to detect one subclinical relapse during the first 2 years after nephrectomy was 112 (95% CI 106-119) and, for 2-5 years after nephrectomy, 500 (416-588).

INTERPRETATION

Planned surveillance imaging captured more than two-thirds of predominantly asymptomatic relapses of Wilms' tumours, with most detected by abdominal ultrasound, chest x-ray, or chest CT scan. Beyond 2 years post-nephrectomy, a substantial number of surveillance scans are needed to capture one relapse, which places a burden on families and health-care systems.

FUNDING

Great Ormond Street Hospital Children's Charity, the European Expert Paediatric Oncology Reference Network for Diagnostics and Treatment, The Danish Childhood Cancer Foundation, Cancer Research UK, the UK National Cancer Research Network and Children's Cancer and Leukaemia Group, Société Française des Cancers de l'Enfant and Association Leon Berard Enfant Cancéreux and Enfant et Santé, Gesellschaft für Pädiatrische Onkologie und Hämatologie and Deutsche Krebshilfe, Grupo Cooperativo Brasileiro para o Tratamento do Tumor de Wilms and Sociedade Brasileira de Oncologia Pediátrica, the Spanish Society of Pediatric Haematology and Oncology and the Spanish Association Against Cancer, and SIOP-Netherlands.

Detecting inflammation in inflammatory bowel disease - how does ultrasound compare to magnetic resonance enterography using standardised scoring systems?

BACKGROUND

Magnetic resonance enterography (MRE) is the current gold standard for imaging in inflammatory bowel disease, but ultrasound (US) is a potential alternative.

OBJECTIVE

To determine whether US is as good as MRE for the detecting inflamed bowel, using a combined consensus score as the reference standard.

MATERIALS AND METHODS

We conducted a retrospective cohort study in children and adolescents <18 years with inflammatory bowel disease (IBD) at a tertiary and quaternary centre. We included children who underwent MRE and US within 4 weeks. We scored MRE using the London score and US using a score adapted from the METRIC (MR Enterography or Ultrasound in Crohn's Disease) trial. Four gastroenterologists assessed an independent clinical consensus score. A combined consensus score using the imaging and clinical scores was agreed upon and used as the reference standard to compare MRE with US.

RESULTS

We included 53 children. At a whole-patient level, MRE scores were 2% higher than US scores. We used Lin coefficient to assess inter-observer variability. The repeatability of MRE scores was poor (Lin 0.6). Agreement for US scoring was substantial (Lin 0.95). There was a significant positive correlation between MRE and clinical consensus scores (Spearman's rho = 0.598, P=0.0053) and US and clinical consensus scores (Spearman's rho = 0.657, P=0.0016).

CONCLUSION

US detects as much clinically significant bowel disease as MRE. It is possible that MRE overestimates the presence of disease when using a scoring system. This study demonstrates the feasibility of using a clinical consensus reference standard in paediatric IBD imaging studies.

Paediatric magnetic resonance enteroclysis under general anaesthesia - initial experience

MR enterography is the accepted imaging reference standard for small bowel assessment in inflammatory bowel disease. There is an increasing cohort of children with inflammatory bowel disease presenting at an early age (<5 years) with severe disease. Younger children present a technical challenge for enterography because of the need for sedation/general anaesthesia to allow image optimisation and the need for oral contrast to allow adequate luminal assessment. Through our experiences, MR enteroclysis under general anaesthesia has proven to be a successful imaging technique for the work-up of these patients. In this paper, we present our institutional practice for performing MR enteroclysis under general anaesthesia.

Apparent diffusion coefficient as it relates to histopathology findings in post-chemotherapy nephroblastoma: a feasibility study

BACKGROUND

Nephroblastomas represent a group of heterogeneous tumours with variable proportions of distinct histopathological components.

OBJECTIVE

The purpose of this study was to investigate whether direct comparison of apparent diffusion coefficient (ADC) measurements with post-resection histopathology subtypes is feasible and whether ADC metrics are related to histopathological components.

MATERIALS AND METHODS

Twenty-three children were eligible for inclusion in this retrospective study. All children had MRI including diffusion-weighted imaging (DWI) after preoperative chemotherapy, just before tumour resection. A pathologist and radiologist identified corresponding slices at MRI and postoperative specimens using tumour morphology, the upper/lower calyx and hilar vessels as reference points. An experienced reader performed ADC measurements, excluding non-enhancing areas. A pathologist reviewed the corresponding postoperative slides according to the international standard guidelines. We tested potential associations with the Spearman rank test.

RESULTS

Side-by-side comparison of MRI-DWI with corresponding histopathology slides was feasible in 15 transverse slices in 9 lesions in 8 patients. Most exclusions were related to extensive areas of necrosis/haemorrhage. In one lesion correlation was not possible because of the different orientation of sectioning of the specimen and MRI slices. The 25% ADC showed a strong relationship with percentage of blastema (Spearman rho=-0.71, P=0.003), whereas median ADC was strongly related to the percentage stroma (Spearman rho=0.74, P=0.002) at histopathology.

CONCLUSION

Side-by-side comparison of MRI-DWI and histopathology is feasible in the majority of patients who do not have massive necrosis and hemorrhage. Blastemal and stromal components have a strong linear relationship with ADC markers.

Intra-Tumor Genetic Heterogeneity in Wilms Tumor: Clonal Evolution and Clinical Implications

The evolution of pediatric solid tumors is poorly understood. There is conflicting evidence of intra-tumor genetic homogeneity vs. heterogeneity (ITGH) in a small number of studies in pediatric solid tumors. A number of copy number aberrations (CNA) are proposed as prognostic biomarkers to stratify patients, for example 1q+ in Wilms tumor (WT); current clinical trials use only one sample per tumor to profile this genetic biomarker. We multisampled 20 WT cases and assessed genome-wide allele-specific CNA and loss of heterozygosity, and inferred tumor evolution, using Illumina CytoSNP12v2.1 arrays, a custom analysis pipeline, and the MEDICC algorithm. We found remarkable diversity of ITGH and evolutionary trajectories in WT. 1q+ is heterogeneous in the majority of tumors with this change, with variable evolutionary timing. We estimate that at least three samples per tumor are needed to detect >95% of cases with 1q+. In contrast, somatic 11p15 LOH is uniformly an early event in WT development. We find evidence of two separate tumor origins in unilateral disease with divergent histology, and in bilateral WT. We also show subclonal changes related to differential response to chemotherapy. Rational trial design to include biomarkers in risk stratification requires tumor multisampling and reliable delineation of ITGH and tumor evolution.

Access and utilisation of healthcare services in rural Tanzania: A comparison of public and non-public facilities using quality, equity, and trust dimensions

This study compared the access and utilisation of health services in public and non-public health facilities in terms of quality, equity and trust in the Mbarali district, Tanzania. Interviews, focus group discussions, and informal discussions were used to generate data. Of the 1836 respondents, 1157 and 679 respondents sought healthcare services on their last visit at public or non-public health facilities, respectively. While 45.5% rated the quality of services to be good in both types of facilities, reported medicine shortages were more pronounced among those who visited public rather than non-public health facilities (OR = 1.7, 95% CI 1.4, 2.1). Respondents who visited public facilities were 4.9 times less likely than those who visited non-public facilities to emphasise the influence of cost in accessing and utilising health care (OR = 4.9, CI 3.9-6.1). A significant difference was also found in the provider-client relationship satisfaction level between non-public (89.1%) and public facilities (74.7%) (OR = 2.8, CI: 1.5-5.0), indicating a level of lower trust in the later. Revised strategies are needed to ensure availability of medicines in public facilities, which are used by the majority of the population, while strengthening private-public partnerships to harmonise healthcare costs.

A multi-Gaussian model for apparent diffusion coefficient histogram analysis of Wilms' tumour subtype and response to chemotherapy

Wilms' tumours (WTs) are large heterogeneous tumours, which typically consist of a mixture of histological cell types, together with regions of chemotherapy-induced regressive change and necrosis. The predominant cell type in a WT is assessed histologically following nephrectomy, and used to assess the tumour subtype and potential risk. The purpose of this study was to develop a mathematical model to identify subregions within WTs with distinct cellular environments in vivo, determined using apparent diffusion coefficient (ADC) values from diffusion-weighted imaging (DWI). We recorded the WT subtype from the histopathology of 32 tumours resected in patients who received DWI prior to surgery after pre-operative chemotherapy had been administered. In 23 of these tumours, DWI data were also available prior to chemotherapy. Histograms of ADC values were analysed using a multi-Gaussian model fitting procedure, which identified 'subpopulations' with distinct cellular environments within the tumour volume. The mean and lower quartile ADC values of the predominant viable tissue subpopulation (ADC(1MEAN), ADC(1LQ)), together with the same parameters from the entire tumour volume (ADC(0MEAN), ADC(0LQ)), were tested as predictors of WT subtype. ADC(1LQ) from the multi-Gaussian model was the most effective parameter for the stratification of WT subtype, with significantly lower values observed in high-risk blastemal-type WTs compared with intermediate-risk stromal, regressive and mixed-type WTs (p < 0.05). No significant difference in ADC(1LQ) was found between blastemal-type and intermediate-risk epithelial-type WTs. The predominant viable tissue subpopulation in every stromal-type WT underwent a positive shift in ADC(1MEAN) after chemotherapy. Our results suggest that our multi-Gaussian model is a useful tool for differentiating distinct cellular regions within WTs, which helps to identify the predominant histological cell type in the tumour in vivo. This shows potential for improving the risk-based stratification of patients at an early stage, and for guiding biopsies to target the most malignant part of the tumour.

Fusion and subtraction post-processing in body MRI

Interpreting complex paediatric body MRI studies requires the integration of information from multiple sequences. Image processing software, some freely available, allows the radiologist to use simple and rapid post-processing techniques that may aid diagnosis. We demonstrate the use of fusion and subtraction post-processing techniques with examples from four areas of application: enterography, oncological imaging, musculoskeletal imaging and MR fistulography.

Intra- and interobserver variability of whole-tumour apparent diffusion coefficient measurements in nephroblastoma: a pilot study

BACKGROUND

The apparent diffusion coefficient (ADC) is potentially useful for assessing treatment response in nephroblastoma (Wilms tumour). However the precision of ADC measurements in these heterogeneous lesions is unknown.

OBJECTIVE

To assess intra- and interobserver variability of whole-tumour ADC measurements in viable parts of nephroblastomas at diagnosis and after preoperative chemotherapy.

MATERIALS AND METHODS

We included children with histopathologically proven nephroblastoma who had undergone MRI with diffusion-weighted imaging before and after preoperative chemotherapy. Three independent observers performed whole-tumour ADC measurements of all lesions, excluding non-enhancing areas. One observer evaluated all lesions on two occasions. We performed analyses using Bland-Altman plots and concordance correlation coefficient (CCC) calculations with 95% limits of agreement for median ADC, difference between pre- and post-chemotherapy median ADC (ADC shift) and percentage of pixels with ADC values <1.0 × 10(-3) mm(2)/s.

RESULTS

In 22 lesions (13 pretreatment and 9 post-treatment) in 10 children the interobserver variability in median ADC and ADC shift were within the interval of approximately ±0.1 × 10(-3) mm(2)/s (limits of agreement for median ADC ranged -0.08-0.11 × 10(-3) mm(2)/s and for ADC-shift -0.11-0.09 × 10(-3) mm(2)/s). The interobserver variability for percentage of low-ADC pixels was larger and also biased. The calculated CCC confirmed good intra- and interobserver agreement (ρ-c ranging from 0.968 to 0.996).

CONCLUSION

Measurements of whole-tumour ADC values excluding necrotic areas seem to be sufficiently precise for detection of chemotherapy-related change.

The accountability for reasonableness approach to guide priority setting in health systems within limited resources--findings from action research at district level in Kenya, Tanzania, and Zambia

BACKGROUND

Priority-setting decisions are based on an important, but not sufficient set of values and thus lead to disagreement on priorities. Accountability for Reasonableness (AFR) is an ethics-based approach to a legitimate and fair priority-setting process that builds upon four conditions: relevance, publicity, appeals, and enforcement, which facilitate agreement on priority-setting decisions and gain support for their implementation. This paper focuses on the assessment of AFR within the project REsponse to ACcountable priority setting for Trust in health systems (REACT).

METHODS

This intervention study applied an action research methodology to assess implementation of AFR in one district in Kenya, Tanzania, and Zambia, respectively. The assessments focused on selected disease, program, and managerial areas. An implementing action research team of core health team members and supporting researchers was formed to implement, and continually assess and improve the application of the four conditions. Researchers evaluated the intervention using qualitative and quantitative data collection and analysis methods.

RESULTS

The values underlying the AFR approach were in all three districts well-aligned with general values expressed by both service providers and community representatives. There was some variation in the interpretations and actual use of the AFR in the decision-making processes in the three districts, and its effect ranged from an increase in awareness of the importance of fairness to a broadened engagement of health team members and other stakeholders in priority setting and other decision-making processes.

CONCLUSIONS

District stakeholders were able to take greater charge of closing the gap between nationally set planning and the local realities and demands of the served communities within the limited resources at hand. This study thus indicates that the operationalization of the four broadly defined and linked conditions is both possible and seems to be responding to an actual demand. This provides arguments for the continued application and further assessment of the potential of AFR in supporting priority-setting and other decision-making processes in health systems to achieve better agreed and more sustainable health improvements linked to a mutual democratic learning with potential wider implications.

MRI: how to perform a pediatric scan

Magnetic resonance imaging (MRI) is rich in diagnostic information but requires optimization for use in children. The main problems are motion artifacts and poor signal-to-noise ratio (SNR). SNR is proportional to voxel volume, which must therefore not be too small, however, usually needs to be reduced compared to adult imaging to account for the finer anatomy of the child. The use of multi-channel coils with element sizes appropriate for the anatomy of interest ensures optimal baseline SNR. Longer acquisition time increases SNR (with a square-root factor), but the flip-side is that this allows more motion artifacts. Attention to patient preparation and to techniques for motion artifact reduction is therefore crucial, and the most important principles are discussed. Low SNR may in part be compensated by optimizing the image contrast by weighting (tissue and lesions T1 and T2 may differ from adults) and by using contrast agents. It is also powerful to combine different image contrasts during postprocessing. The basic principles are discussed, followed by an example scan protocol.

Advances in pediatric oncology MRI

Refined stratification of disease is thought to result in better survival from childhood malignant disease while minimizing the adverse effects of anticancer therapies. There is a potential for magnetic resonance imaging (MRI) to contribute to such stratification by improved tissue characterization, anatomical depiction, staging, and assessment of early treatment response. Recent advances in pediatric MRI outside the central nervous system (CNS) are reviewed in this context. The focus is on new applications for conventional MRI and on clinical implementation of tissue-specific and quantitative techniques. This area is largely unexplored, and potential directions for research are indicated.

Contrast-enhanced magnetic resonance imaging in pediatric patients: review and recommendations for current practice

Magnetic resonance imaging (MRI), frequently with contrast enhancement, is the preferred imaging modality for many indications in children. Practice varies widely between centers, reflecting the rapid pace of change and the need for further research. Guide-line changes, for example on contrast-medium choice, require continued practice reappraisal. This article reviews recent developments in pediatric contrast-enhanced MRI and offers recommendations on current best practice. Nine leading pediatric radiologists from internationally recognized radiology centers convened at a consensus meeting in Bordeaux, France, to discuss applications of contrast-enhanced MRI across a range of indications in children. Review of the literature indicated that few published data provide guidance on best practice in pediatric MRI. Discussion among the experts concluded that MRI is preferred over ionizing-radiation modalities for many indications, with advantages in safety and efficacy. Awareness of age-specific adaptations in MRI technique can optimize image quality. Gadolinium-based contrast media are recommended for enhancing imaging quality. The choice of most appropriate contrast medium should be based on criteria of safety, tolerability, and efficacy, characterized in age-specific clinical trials and personal experience.

Implementing accountability for reasonableness framework at district level in Tanzania: a realist evaluation

Background

Despite the growing importance of the Accountability for Reasonableness (A4R) framework in priority setting worldwide, there is still an inadequate understanding of the processes and mechanisms underlying its influence on legitimacy and fairness, as conceived and reflected in service management processes and outcomes. As a result, the ability to draw scientifically sound lessons for the application of the framework to services and interventions is limited. This paper evaluates the experiences of implementing the A4R approach in Mbarali District, Tanzania, in order to find out how the innovation was shaped, enabled, and constrained by the interaction between contexts, mechanisms and outcomes.

Methods

This study draws on the principles of realist evaluation -- a largely qualitative approach, chiefly concerned with testing and refining programme theories by exploring the complex interactions of contexts, mechanisms, and outcomes. Mixed methods were used in data collection, including individual interviews, non-participant observation, and document reviews. A thematic framework approach was adopted for the data analysis.

Results

The study found that while the A4R approach to priority setting was helpful in strengthening transparency, accountability, stakeholder engagement, and fairness, the efforts at integrating it into the current district health system were challenging. Participatory structures under the decentralisation framework, central government's call for partnership in district-level planning and priority setting, perceived needs of stakeholders, as well as active engagement between researchers and decision makers all facilitated the adoption and implementation of the innovation. In contrast, however, limited local autonomy, low level of public awareness, unreliable and untimely funding, inadequate accountability mechanisms, and limited local resources were the major contextual factors that hampered the full implementation.

Conclusion

This study documents an important first step in the effort to introduce the ethical framework A4R into district planning processes. This study supports the idea that a greater involvement and accountability among local actors through the A4R process may increase the legitimacy and fairness of priority-setting decisions. Support from researchers in providing a broader and more detailed analysis of health system elements, and the socio-cultural context, could lead to better prediction of the effects of the innovation and pinpoint stakeholders' concerns, thereby illuminating areas that require special attention to promote sustainability.

Decentralized health care priority-setting in Tanzania: evaluating against the accountability for reasonableness framework

Priority-setting has become one of the biggest challenges faced by health decision-makers worldwide. Fairness is a key goal of priority-setting and Accountability for Reasonableness has emerged as a guiding framework for fair priority-setting. This paper describes the processes of setting health care priorities in Mbarali district, Tanzania, and evaluates the descriptions against Accountability for Reasonableness. Key informant interviews were conducted with district health managers, local government officials and other stakeholders using a semi-structured interview guide. Relevant documents were also gathered and group priority-setting in the district was observed. The results indicate that, while Tanzania has a decentralized public health care system, the reality of the district level priority-setting process was that it was not nearly as participatory as the official guidelines suggest it should have been. Priority-setting usually occurred in the context of budget cycles and the process was driven by historical allocation. Stakeholders' involvement in the process was minimal. Decisions (but not the reasoning behind them) were publicized through circulars and notice boards, but there were no formal mechanisms in place to ensure that this information reached the public. There were neither formal mechanisms for challenging decisions nor an adequate enforcement mechanism to ensure that decisions were made in a fair and equitable manner. Therefore, priority-setting in Mbarali district did not satisfy all four conditions of Accountability for Reasonableness; namely relevance, publicity, appeals and revision, and enforcement. This paper aims to make two important contributions to this problematic situation. First, it provides empirical analysis of priority-setting at the district level in the contexts of low-income countries. Second, it provides guidance to decision-makers on how to improve fairness, legitimacy, and sustainability of the priority-setting process.

Women's experiences and views about costs of seeking malaria chemoprevention and other antenatal services: a qualitative study from two districts in rural Tanzania

BACKGROUND

The Tanzanian government recommends women who attend antenatal care (ANC) clinics to accept receiving intermittent preventive treatment against malaria during pregnancy (IPTp) and vouchers for insecticide-treated nets (ITNs) at subsidized prices. Little emphasis has been paid to investigate the ability of pregnant women to access and effectively utilize these services.

OBJECTIVES

To describe the experience and perceptions of pregnant women about costs and cost barriers for accessing ANC services with emphasis on IPTp in rural Tanzania.

METHODS

Qualitative data were collected in the districts of Mufindi in Iringa Region and Mkuranga in Coast Region through 1) focus group discussions (FGDs) with pregnant women and mothers to infants and 2) exit-interviews with pregnant women identified at ANC clinics. Data were analyzed manually using qualitative content analysis methodology.

FINDINGS

FGD participants and interview respondents identified the following key limiting factors for women's use of ANC services: 1) costs in terms of money and time associated with accessing ANC clinics, 2) the presence of more or less official user-fees for some services within the ANC package, and 3) service providers' application of fines, penalties and blame when failing to adhere to service schedules. Interestingly, the time associated with travelling long distances to ANC clinics and ITN retailers and with waiting for services at clinic-level was a major factor of discouragement in the health seeking behaviour of pregnant women because it seriously affected their domestic responsibilities.

CONCLUSION

A variety of resource-related factors were shown to affect the health seeking behaviour of pregnant women in rural Tanzania. Thus, accessibility to ANC services was hampered by direct and indirect costs, travel distances and waiting time. Strengthening of user-fee exemption practices and bringing services closer to the users, for example by promoting community-directed control of selected public health services, including IPTp, are urgently needed measures for increasing equity in health services in Tanzania.

Common fetal measurements: a comparison between ultrasound and magnetic resonance imaging

BACKGROUND

Ultrasound has been the method of choice for antenatal fetal assessment for the past three decades; however, problems may arise in cases of oligohydramnion, unfavorable position of the fetus, and maternal obesity.

PURPOSE

To compare ultrasound (US) and magnetic resonance imaging (MRI) for common fetal measurements at 19-30 weeks' gestation, and to assess the effect of high maternal body-mass index (BMI).

MATERIAL AND METHODS

59 low-risk singleton pregnancies were enrolled in a prospective blinded cross-sectional study. In a first session, an experienced obstetrician used a high-resolution US technique and in a second session on the same day MRI was used to measure biparietal diameter (BPD), head circumference (HC), mean abdominal diameter (MAD), abdominal circumference (AC), and femur length (FL). Inter- and intraobserver and intermodality variability was determined using Bland-Altman plots. The effect of maternal BMI was assessed using Spearman's statistics.

RESULTS

A total of 45 women aged 19-43 years (median 29 years) attended both US and MRI at median 22 weeks' gestation. The mean differences between US and MRI were 1.6 mm for HC (95% confidence interval [CI] -1.0, 4.3 mm), 1 mm for AC (95% CI -0.2, 4.0 mm), 0.2 mm for MAD (95% CI -0.7, 1.2 mm), 2.2 mm for BPD (95% CI 1.7, 2.7 mm), and 4.6 mm for FL (95% CI 2.9, 6.4 mm). Maternal BMI did not affect the results (Spearman' rho 0.054-0.277; P=NS). The intraobserver agreement for all MRI measurements was acceptable, except for FL, while the interobserver agreement was poor.

CONCLUSION

There was good agreement between US and MRI for common fetal measurements, but not for all (i.e., BPD and particularly FL). MRI had a poor interobserver agreement, underscoring the need for technical refinement and reference ranges specifically established for MRI.

Gadolinium and nephrogenic systemic fibrosis: time to tighten practice

Nephrogenic systemic fibrosis (NSF) is a relatively new entity, first described in 1997. Few cases have been reported, but the disease has high morbidity and mortality. To date it has been seen exclusively in patients with renal dysfunction. There is an emerging link with intravenous injection of gadolinium contrast agents, which has been suggested as a main triggering factor, with a lag time of days to weeks. Risk factors include the severity of renal impairment, major surgery, vascular events and other proinflammatory conditions. There is no reason to believe that children have an altered risk compared to the adult population. It is important that the paediatric radiologist acknowledges emerging information on NSF but at the same time considers the risk:benefit ratio prior to embarking on alternative investigations, as children with chronic kidney disease require high-quality diagnostic imaging.

Tumors in pediatric patients at diffusion-weighted MR imaging: apparent diffusion coefficient and tumor cellularity

PURPOSE

To prospectively assess whether there is a relationship between the apparent diffusion coefficient (ADC) and the histopathologic cell count and whether the ADC can enable differentiation of benign and malignant extracranial mass lesions in children.

MATERIALS AND METHODS

Institutional ethics approval and parent or guardian consent were obtained. Eleven malignant and eight benign lesions in 19 children (11 girls, eight boys; median age, 3.9 years; age range, 11 days to 15.5 years) who underwent magnetic resonance (MR) imaging of extracranial mass lesions-including a diffusion-weighted sequence (with b values 0, 500, and 1000 sec/mm(2))-and histopathologic analysis to prove findings were studied. The median ADC within each mass lesion was compared with the median cell count for 10 high-power microscopic fields in the specimen. The inverse regression between cell count and ADC was calculated. The difference in ADC between benign and malignant lesions was assessed by using the Mann-Whitney U test.

RESULTS

There was an inverse relationship between ADC and cell count, expressed as ADC (in x10(-3) mm(2)/sec) = 0.56 + (66.2/cell count), with a relatively good fit to the observed data (analysis of variance R(2) = 0.541, F = 20.0, P < .001). The ADCs of benign lesions ranged from (0.84-2.83) x 10(-3) mm(2)/sec (median, 1.35 x 10(-3) mm(2)/sec; standard deviation, 0.68). The ADCs of malignant lesions ranged from (0.73-1.53) x 10(-3) mm(2)/sec (median, 1.00 x 10(-3) mm(2)/sec; standard deviation, 0.29). There was no significant difference in ADC between benign and malignant lesions (Mann-Whitney U = 22, P = .069). All highly cellular (>150 cells per high-power field) lesions had an ADC lower than 1.5 x 10(-3) mm(2)/sec.

CONCLUSION

Although there is a significant relationship between cellularity and ADC, cell count probably is not the sole determinant of the ADC. Use of the ADC cannot enable accurate differentiation of malignant and benign lesions.

Surveillance for Wilms tumour in at-risk children: pragmatic recommendations for best practice

BACKGROUND

Most Wilms tumours occur in otherwise healthy children, but a small proportion occur in children with genetic syndromes associated with increased risks of Wilms tumour. Surveillance for Wilms tumour has become widespread, despite a lack of clarity about which children are at increased risk of these tumours and limited evidence of the efficacy of screening or guidance as to how screening should be implemented.

METHODS

The available literature was reviewed.

RESULTS

The potential risks and benefits of Wilms tumour surveillance are finely balanced and there is no clear evidence that screening reduces mortality or morbidity. Prospective evidence-based data on the efficacy of Wilms tumour screening would be difficult and costly to generate and are unlikely to become available in the foreseeable future.

CONCLUSIONS

The following pragmatic recommendations have been formulated for Wilms tumour surveillance in children at risk, based on our review: (1) Surveillance should be offered to children at >5% risk of Wilms tumour. (2) Surveillance should only be offered after review by a clinical geneticist. (3) Surveillance should be carried out by renal ultrasonography every 3-4 months. (4) Surveillance should continue until 5 years of age in all conditions except Beckwith-Wiedemann syndrome, Simpson-Golabi-Behmel syndrome and some familial Wilms tumour pedigrees where it should continue until 7 years. (5) Surveillance can be undertaken at a local centre, but should be carried out by someone with experience in paediatric ultrasonography. (6) Screen-detected lesions should be managed at a specialist centre.

Is there a role for CT in the neonate?

Choice of imaging modalities should be based on scientific proof and best practice guidelines. However, in the neonatal age group there is a paucity of medical evidence, and imaging is often guided by local experience, availability of equipment and expertise, and by logistical factors. This paper discusses possible indications for CT in the neonate, the associated radiation protection issues, common CT findings and potential pitfalls in technique and image interpretation. Due to the particular range of abnormalities in this age group, imaging must be tailored to the individual, and should in most cases be done in specialist units.

Atypical abdominal paediatric lymphangiomatosis: diagnosis aided by diffusion-weighted MRI

We report a 4-year-old child with a mesenteric mass, which on ultrasound, CT and conventional MRI appeared solid, raising lymphoma as a possible diagnosis. Diffusion weighted MRI (DW-MRI), however, suggested a low-cellularity lesion, making lymphoma less likely. Biopsy confirmed lymphangioma. DW-MRI may be a useful adjunct to conventional imaging, even in the abdomen.

Garlic arrests MDA-MB-435 cancer cells in mitosis, phosphorylates the proapoptotic BH3-only protein BimEL and induces apoptosis

Components of garlic (Allium sativum) can cause disruption of microtubules, cell cycle arrest, and apoptosis in cancer cells. We show here that a water-soluble extract of garlic arrested MDA-MB-435 cancer cells in mitosis and caused apoptosis. The proapoptotic BH3-only, bcl-2 family protein Bim_EL, which in healthy cells can be tightly sequestered to the microtubule-associated dynein motor complex, was modified after garlic treatment. The main effect of garlic on Bim_EL was a considerable increase in a phosphorylated form of the protein. This phosphorylation(s), probably partly dependent on c-jun N-terminal kinase activity, promoted mitochondrial localisation of Bim_EL. Furthermore, inhibition of extracellular signal-regulated kinases 1/2 increased the amount of another form of Bim_EL present in the mitochondrial cellular fraction. Treatment of cells with the garlic compound diallyl disulphide had similar effects on Bim_EL. The results indicate that the apoptotic effect of garlic and a combination of garlic and the inhibitor of extracellular signal-regulated kinases 1/2 in MDA-MB-435 cells partly is due to modifications that are necessary for translocation of the proapoptotic protein Bim_EL to mitochondria where it executes its proapoptotic function.

Complicated deliveries, critical care and quality in Emergency Obstetric Care in Northern Tanzania

Our objective was to determine the availability and quality of obstetric care to improve resource allocation in northern Tanzania. We surveyed all facilities providing delivery services (n=129) in six districts in northern Tanzania using the UN Guidelines for monitoring emergency obstetric care (EmOC). The three last questions in this audit outline are examined: Are the right women (those with obstetric complications) using emergency obstetric care facilities (Met Need)? Are sufficient quantities of critical services being provided (cesarean section rate (CSR))? Is the quality of the services adequate (case fatality rate (CFR))? Complications are calculated using Plan 3 of the UN Guidelines to assess the value of routine data for EmOC indicator monitoring. Nearly 60% of the expected complicated deliveries in the study population were conducted at EmOC qualified health facilities. 81.2% of the expected complicated deliveries are conducted in any facility (including facilities not qualifying as EmOC facilities). There is an inadequate level of critical services provided (CSR 4.6). Voluntary agencies provide most of these services in rural settings. All indicators show large variations with the setting (urban/rural location, level and ownership of facilities). Finally, there is large variation in the CFR with only one facility meeting the minimum accepted level. Utilization and quality of critical obstetric services at lower levels and in rural districts must be improved. The potential for improving the resource allocation within lower levels of the health care system is discussed. Given the small number of qualified facilities yet relatively high Met Need, we argue that it is neither the mothers' ignorance nor their lack of ability to get to a facility that is the main barrier to receiving quality care when needed, but rather the lack of quality care at the facility. Little can be concluded using the CFR to describe the quality of services provided.

Changes in computed tomography features following preoperative chemotherapy for nephroblastoma: relation to histopathological classification

The objective of this study is to assess computed tomography (CT) changes, both volume estimates and subjective features, following preoperative chemotherapy for nephroblastoma (Wilms' tumour) in patients treated on the United Kingdom Children's Cancer Study Group Wilms' Tumour Study-3 (UKW-3) protocol and to compare CT changes and histopathological classification. Twenty-one nephroblastomas in 15 patients treated on UKW-3 were included. All patients were examined by CT before and after preoperative chemotherapy treatment. CT images were reviewed (estimated volume change and subjectively assessed features). CT changes were compared to histopathological classification. Of the 21 tumours, all five high-risk tumours decreased in volume following chemotherapy (median -79%; range -37 to -91%). The sole low-risk tumour decreased in volume by 98%. Ten intermediate-risk tumours decreased in volume (median -72%; range -6 to -98%) and five intermediate-risk tumours increased (median +110%; range +11 to +164%). None of the five high-risk tumours, compared to 15/16 intermediate or low-risk tumours, became less dense and/or more homogeneous, or virtually disappeared, following chemotherapy. Volume change following chemotherapy did not relate to histopathological risk group. Changes in subjectively assessed qualitative CT features were more strongly related to histopathological risk group.

Ossification sequence in infants who die during the perinatal period: population-based references

PURPOSE

To determine population-based references for the relationships between the presence of ossification centers and gestational age and skeletal length measurements among infants who die during the perinatal period, as well as to evaluate the possible influence of intrauterine growth restriction on ossification stage.

MATERIALS AND METHODS

During an 11-year period, nearly all infants who died perinatally in a well-defined geographic area routinely underwent radiography with a standardized technique. The presence of visible secondary ossification centers in the singletons (n = 495) was evaluated. Cluster analysis was used to identify stages of ossification; a sequential appearance of secondary ossification centers was assumed. Comparisons were made with Wilks lambda between male and female infants and between infants who were presumed to have growth restriction and those who were not. Reference ranges for the presence of ossification centers were calculated for interquartile ranges of femur length and gestational age.

RESULTS

Eight clusters of ossification defining different stages of ossification of the pelvis, hindfeet, and knees were identified. The sequential clusters outlined well-defined intervals of femur length and gestational age. Bone lengths, birth weight, and gestational age within ossification clusters did not differ between the sexes (Wilks lambda = 0.989, P =.532) or according to whether growth restriction was presumed to exist (Wilks lambda = 0.958, P =.481).

CONCLUSION

The reference diagrams calculated with this method indicate relationships between ossification sequence and both gestational age and skeletal length measurements.

Skeletal measurements among infants who die during the perinatal period: new population-based reference

BACKGROUND

Reference data for roentgen skeletal measurements among infants who die during the perinatal period is not available, although it might prove helpful in the study of pre-autopsy radiographs.

OBJECTIVE

Our aim was to define new population-based reference data for skeletal measurements among infants who die during the perinatal period.

MATERIALS AND METHODS

We routinely took standardised pre-autopsy radiographs of aborted and stillborn fetuses from 16 weeks gestational age to 7 days after delivery during a period of 11 years in our hospital. The data presented here represents nearly all perinatal deaths in a well-defined geographical area during the study period. We calculated detailed plots of estimated 10th-90th centiles and quartiles of different skeletal measurements by gestational age at death.

RESULTS

High correlations were seen between birth weight and the different skeletal measurements, including cranial width ( r>0.9, P<0.001). We were not able to identify any asymmetrical pattern of skeletal growth. Reference plots for femoral, tibial, humeral, radial and lumbar spine lengths, and for pelvic width are presented.

CONCLUSIONS

We suggest that the current population-based reference data might be beneficial, and that skeletal radiographic measurements might contribute substantially in the assessment of fetal growth stage and in detection of skeletal abnormalities in infants who die during the perinatal period.

Congenital absence of the nose: a case report and literature review

A case of congenital absence of the nose is presented. The etiology of this rare condition is unknown. A review of the literature reveals that the previously applied terms, e.g. 'arhinia', are unclear. In the reviewed cases there seems to be a pattern of facial anomalies associated with nasal absence. In most cases, one could probably expect a lack of the olfactory bulbs and tracts. We suggest a new terminology and summarize the aims of the radiological evaluation of this condition.