A radiofrequency coil for infants and toddlers.

Infants and toddlers are a challenging population upon which to perform magnetic resonance imaging (MRI) of the brain, both in research and clinical settings. Because of the large range in head size during the early years of development, paediatric neuro-MRI requires a radiofrequency (RF) coil, or set of coils, that is tailored to head size to provide the highest image quality. Mitigating techniques must also be employed to reduce and correct for subject motion. This manuscript describes an RF coil with a tailored mechanical-electrical design that can adapt to the head size of 3-month-old infants to 3-year-old toddlers. The RF coil was designed with tight-fitting coil elements to improve the signal-to-noise ratio (SNR) in comparison with commercially available adult head coils, while simultaneously aiding in immobilization. The coil was designed without visual obstruction to facilitate an unimpeded view of the child's face and the potential application of camera or motion-tracking systems. Despite the lack of elements over the face, the paediatric coil produced higher SNR over most of the brain compared with adult coils, including more than twofold in the periphery. Acceleration rates of fourfold in each Cartesian direction could be achieved. High SNR allowed for short acquisition times through accelerated imaging protocols and reduced the probability of motion during a scan. Modification of the acquisition protocol, with immobilization of the head through the adjustable coil geometry, and subsequently being combined with a motion-tracking system, provides a compelling platform for scanning paediatric populations without sedation and with improved image quality.

Post-Mortem Magnetic Resonance Imaging Appearances of Feticide in Perinatal Deaths.

OBJECTIVE: The aim of this study was to characterise the imaging features seen in fetuses having undergone feticide by intracardiac potassium chloride injection compared to those of non-terminated fetuses at post-mortem magnetic resonance imaging (PMMRI). METHODS: A case-control study was performed comparing PMMRI findings between two groups of patients - those having undergone feticide were matched to a control group of miscarried/stillborn fetuses. The groups were matched according to gestational age, weight, and time since death. Two independent readers reviewed the PMMRI for thoracic, abdominal, and musculoskeletal imaging features. The Fishers exact test was conducted for differences between the patient groups. RESULTS: Twenty-six cases of feticide (mean gestation 25 weeks [20-36]) and 75 non-terminated fetuses (mean gestation 26.7 weeks [19-36]) were compared. There was a higher proportion of feticide cases demonstrating pneumothorax (23.1 vs. 1.3%, p = 0.001), haemothorax (42.3 vs. 4%, p = 0.001), pneumopericardium (30.8 vs. 5.3%, p = 0.002), and haemopericardium (34.6 vs. 0%, p = 0.0001). Intracardiac gas and intra-abdominal findings were higher in the feticide group, but the differences were not statistically significant. CONCLUSION: Characteristic PMMRI features of feticide can help improve reporter confidence in differentiating iatrogenic from physiological/pathological processes.

Early US findings of biliary atresia in infants younger than 30 days.

PURPOSE: To investigate and compare ultrasound (US) findings for the diagnosis of biliary atresia (BA) in infants younger than 30 days with those of infants older than 30 days. MATERIALS AND METHODS: From 2000 to 2015, we reviewed hepatobiliary US images in 12 BA infants younger than 30 days (younger BA group) and 62 BA infants older than 30 days (older BA group) before Kasai procedure. Eight (67%) of younger BA group underwent follow-up US examinations before Kasai procedure. Our review of the images focused on triangular cord sign, gallbladder (GB) abnormalities, vascular changes, and signs of portal hypertension. RESULTS: The triangular cord sign was present in 17% of younger BA group and in 56% of older BA group (P=.024). GB abnormalities were commonly identified in both groups. The hepatic artery diameter was significantly smaller in younger BA group than in older BA group (P<.001). Signs of portal hypertension were less common in younger BA group (17%) than in older BA group (84%) (P<.001). Follow-up US of two infants in younger BA group showed a new appearance of the triangular cord sign. CONCLUSION: BA infants younger than 30 days showed atypical US findings compared with those older than 30 days. KEY POINTS: • BA infants younger than 30 days show atypical US findings. • GB abnormalities were common in both younger and older BA group. • Subsequent US examination may be helpful to diagnose BA in young infants.

Unlocking the potential of photon counting detector CT for paediatric imaging: a pictorial essay.

Recent advancements in CT technology have introduced a revolutionary innovation to practice known as the Photon-Counting detector (PCD) CT imaging. The pivotal hardware enhancement of the PCD-CT scanner lies in its detectors, which consist of smaller pixels than standard detectors and allow direct conversion of individual X-rays to electrical signals. As a result, CT images are reconstructed at higher spatial resolution (as low as 0.2 mm) and reduced overall noise, at no expense of an increased radiation dose. These features are crucial for paediatric imaging, especially for infants and young children, where anatomical structures are notably smaller than in adults and in whom keeping dose as low as possible is especially relevant. Since January 2022, our hospital has had the opportunity to work with PCD-CT technology for paediatric imaging. This pictorial review will showcase clinical examples of PCD-CT imaging in children. The aim of this pictorial review is to outline the potential paediatric applications of PCD-CT across different anatomical regions, as well as to discuss the benefits in utilizing PCD-CT in comparison to conventional standard energy integrating detector CT.

Lung ultrasound in neonates - An underused tool.

Point of care lung ultrasound (USG) can help in the diagnosis and management of critically sick neonates. It is based on seven simple principles that are comprehensive enough to diagnose all major lung pathologies. A compact small machine and a micro-convex or linear probe are the basic requirements to perform lung USG. In contrast to traditional USG principles, USG of the lung is based on artefacts. Some of the terminologies that are used to characterize normal lung include the pleural line, A-line, bat sign, lung sliding and seashore sign. Air/fluid mixture in varying ratios helps in diagnosis of normal lung, pneumothorax, interstitial syndrome (transient tachypnoea of newborn, respiratory distress syndrome, bronchopulmonary dysplasia), lung consolidation and pleural effusion.

Cinematic versus volume rendered imaging for the depiction of complex congenital heart disease.

INTRODUCTION: Planning for surgical intervention for patients with complex congenital heart disease requires a comprehensive understanding of the individual's anatomy. Cinematic rendering (CR) is a novel technique that purportedly builds on traditional volume rendering (VR) by converting CT image data into clearly defined 3D reconstructions through the stimulation and propagation of light rays. The purpose of this study was to compare CR to VR for the understanding of critical anatomy in unoperated complex congenital heart disease. METHODS: In this retrospective study, CT data sets from 20 sequential scanned cases of unoperated paediatric patients with complex congenital heart disease were included. 3D images were produced at standardised and selected orientations, matched for both VR and CR. The images were then independently reviewed by two cardiologists, two radiologists and two surgeons for overall image quality, depth perception and the visualisation of surgically relevant anatomy, the coronary arteries and the pulmonary veins. RESULTS: Cinematic rendering demonstrated significantly superior image quality, depth perception and visualisation of surgically relevant anatomy than VR. CONCLUSION: Cinematic rendering is a novel 3D CT-rendering technique that may surpass the traditionally used volumetric rendering technique in the provision of actionable pre-operative anatomical detail for complex congenital heart disease.

Traumatic pseudoaneurysm of the internal iliac artery following bone marrow aspiration in a child: An extremely rare complication of a very common procedure.

Presented here is a very rare and potentially life-threatening complication of a very common procedure. Vascular injury with traumatic pseudoaneurysm following BMAT in a paediatric patient has only been reported once in the literature to the best of our knowledge. Presented here is a second case, with pathognomonic imaging findings on CT that underwent successful coil embolisation.

Radiation risk-benefit communication during paediatric CT imaging: Experiences of radiographers at two public hospitals.

INTRODUCTION: Radiation dose knowledge and effective communication skills are essential for both radiographers and radiologists to be able to appropriately fulfil their legal responsibilities to justify each medical exposure. Furthermore, they enable the optimisation of imaging protocols and techniques according to the child's characteristics and underlying clinical conditions. Previous studies have shown that radiographers do not provide paediatric patients and their parents/guardians with adequate information about doses and risks before a procedure. However, they have a legal responsibility to explain the radiation risk associated with performing the procedure as well as the associated risk of not performing the same procedure. There are several obstacles to describing ionizing radiation risk, including the ionizing radiation language that is not readily understood by non-imaging personnel. This study aimed to explore and describe the radiographers' experiences of radiation risk-benefit communication during paediatric CT imaging at two public hospitals. This is important to understand the effectiveness of the communication process and institute corrective action where shortcomings are evident. METHODS: A qualitative, exploratory, descriptive research design was applied. The sample consisted of 12 purposively selected radiographers who were trained and working in the CT imaging department. Data were collected using face-to-face individual interviews. Tesch's 8 steps were used to analyse the data collected and generate themes and subthemes. RESULTS: Two themes emerged from the data collected: (1)Positive experiences with two sub-themes (job satisfaction and mutual benefit) and (2) negative experiences with three sub-themes (.professional deprecation, ineffectual outcomes and communication impediments). CONCLUSION: Positive experiences boosted radiographers' confidence and enhanced their participation in radiation risk-benefit communication with paediatric patients' parents and guardians while negative experiences hindered patient-centred care in the process of risk-benefit communication. IMPLICATIONS FOR PRACTICE: Continuous education of radiographers and doctors on radiation risk-benefit communication before paediatric CT procedures is recommended, in line with their scope of practice, to improve patient-centred care.

Neuroimaging manifestations of paediatric histiocytoses.

Histiocytoses are rare multi-system disorders marked by abnormal histiocyte cell proliferation, affecting children with diverse clinical presentations. Classified into five groups in 2016, including Langerhans-related (L), cutaneous (C), malignant (M), Rosai-Dorfman disease (R) and haemophagocytic lymphohistiocytosis (H), newer entities such as ALK-positive histiocytosis have also emerged, heralding the era of molecular (sub)classification. Common entities include Langerhans cell histiocytosis (LCH), Erdheim-Chester disease (ECD), Rosai-Dorfman disease (RDD) and haemophagocytic lymphohistiocytosis (HLH). This pictorial essay aids radiologists in recognising and differentiating paediatric histiocytoses based on unique neuroimaging features.

Low-cost chest paediatric phantom for dose optimisation: construction and validation.

INTRODUCTION AND OBJECTIVES: In order to perform chest dose optimisation studies, the imaging phantom should be adequate for image quality evaluation. Since high-end phantoms are cost prohibitive, there is a need for a low-cost construction method with fairly available tissue substitutes. MATERIALS AND METHODS: Theoretical calculations of radiological characteristics were performed for each of lung, cortical bone and soft tissues in order to choose appropriate substitute, then, cork, P.V.C. (Polyvinyl chloride) and water were chosen, respectively. Validation included, firstly, measuring CT Hounsfield Units (HU) of a real patient's tissues then compared against their corresponding anatomies in the constructed phantom. Secondly, Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) values were acquired in this study to evaluate the quality of images generated from the constructed phantom, then, compare their trends with a valid phantom under different exposure parameters (kVp and mAs). RESULTS: From theoretical calculations, the percentage differences showed high accuracy of tissue substitutes when simulating real patient tissues; P.V.C. was ≥5.78%, cork was ≥4.46% and water ≥5%. The percentage difference (CT HU) between lung and cortical bone and their equivalent tissue substitutes were 10.44% and 0.53%-3.17%, respectively. Strong positive correlations were found for SNR when changing both kVp (0.79) and mAs (0.65). While the correlation strength of CNR values were found to be moderate when changing both kVp (0.58) and mAs (0.53). CONCLUSIONS: Our low-cost phantom approved through CT HU that their materials replicate the radiological characteristics of real one-year-old child while SNR and SNR correlations confirmed its applicability in imaging and optimisation studies.

Is there benefit to concurrent x-ray imaging of the wrist, forearm and elbow in paediatric patients following a fall on the outstretched hand?

INTRODUCTION: Concurrent X-ray imaging of the wrist, forearm and elbow in paediatric patients following a fall on the outstretched hand (FOOSH) is intended to minimise the risk of an undetected co-occurring injury and is typically performed on patients aged 0-10 years. The purpose of this study was to explore the benefit of this strategy and to identify if age could provide evidence for imaging. METHODS: A 12-month retrospective review of all X-ray examinations of the wrist, forearm and distal humerus of patients aged 0-10 years referred from the Emergency Department of Logan Hospital, Queensland was undertaken. The frequency, type and location of radiographic abnormalities and the requested examinations region of interest (ROI), referral notation and patient's age were recorded. Analysis was made by descriptive statistics. RESULTS: Four hundred and seventy-six examinations met the studies inclusion criteria, 4.8% (n = 23) identified an abnormality outside of the documented ROI. On review of the admission and treatment notes, 1.7% (n = 8) were deemed to have detected traumatic abnormalities as a direct outcome of concurrent imaging. No age-related evidence for imaging was identified. CONCLUSION: This study demonstrates limited benefit (1.7%) to concurrent imaging following a FOOSH. The results suggest that a thorough physical evaluation of the paediatric upper limb performed by the referrer is sufficient to accurately guide X-ray imaging. These findings have the potential to positively impact a reduction in the number of X-rays performed on paediatric patients and in turn contribute to limiting radiation dose. Further studies may be beneficial in verifying the study's findings.

Lessons learnt from the global iodinated contrast media shortage in head and neck imaging.

A recent shortage in the global supply of iodinated contrast media (ICM) has required health service providers to review their contrast administration policies and implement strategies to conserve inventory. This article will review the current best practices in head and neck imaging for a variety of common presentations and provide examples where alternative imaging can be considered due to the recent ICM shortage. Ultrasound and MRI techniques can feature heavily in many diagnostic processes in head and neck pathology, and a variety of common presentations can be appropriately investigated through clinical evaluation or naso-endoscopy. In many instances, for the routine assessment of non-acute adult and paediatric head and neck presentations, the use of contrast-enhanced CT can be safely minimised to conserve ICM if required.

Prostate abscess in a paediatric patient: A rare diagnosis.

Prostate abscess (PA) is an uncommon clinical manifestation that typically presents in the fifth to sixth decade of age and sporadically affects neonates. These characteristics, coupled with the atypical presentation, represent a clinical dilemma and a challenging diagnosis. A detailed history depicting the clinical course and the presence of risk factors is imperative to alert the clinician of the possibility of a PA. In this case report, we present a surgically confirmed PA, a diagnosis that is rarely encountered within the paediatric age group.

Multimodality imaging review for suspected ovarian torsion cases in children.

OBJECTIVES: Ovarian torsion (OT), although rare, can be described as a complete or partial twist of the ovary with impairment of blood flow. Although occurring at any age, it is more common in children and during pregnancy. Presenting symptoms are non-specific but include either persistent or intermittent acute abdominal pain, making early diagnosis difficult. Delayed diagnosis is associated with an increased need for oophorectomy. The aim of this literature review is to establish the safest and most efficacious imaging strategy for OT by comparing and contrasting evidence for current imaging modalities found in the literature. KEY FINDINGS: Characteristically, OT can be identified through a combination of findings some of which includes an enlarged ovary, multiple follicles at the periphery and a "whirlpool" sign. Currently, ultrasound is the preferred primary imaging modality; although computed tomography (CT) and magnetic resonance imaging (MRI) may also be used when findings are equivocal; with MRI being the safer option. CONCLUSION: Ultimately, while it is true that ovarian torsion is not a common cause of acute abdominal pain in children, it should always be considered in the differential diagnosis. Prior to selecting an imaging modality; the clinical presentation, age group, possible radiation dose and availability of the modality needs to be considered to ensure the appropriate imaging strategy. IMPLICATIONS FOR PRACTICE: With new tools such as scoring systems, B-flow imaging (BFI), diffusion-weighted imaging (DWI) and susceptibility-weighted imaging (SWI) currently being explored for possible use in the future, early diagnosis of OT may be attainable. Thus, reducing the likelihood of adverse complications and consequently the need for oophorectomy.

Reducing Radiation Exposure to Paediatric Patients Undergoing [18F]FDG-PET/CT Imaging.

PURPOSE: To investigate the possibility of reducing the injected activity for whole-body [18F]FDG-PET/CT studies of paediatric oncology patients and to assess the usefulness of time-of-flight (TOF) acquisition on PET image quality at reduced count levels. PROCEDURES: Twenty-nine paediatric oncology patients (12F/17M, 3-18 years old (median age 13y), weight 45±20 kg, BMI 19±4 kg/m2), who underwent routine whole-body PET/CT examinations on a Siemens Biograph mCT TrueV system with TOF capability (555ps) were included in this study. The mean injected activity was 156 ± 45 MBq (3.8 ± 0.8 kg/MBq) and scaled to patient weight. The raw data was collected in listmode (LM) format and pre-processed to simulate reduced levels of [18F]FDG activity (75, 50, 35, 20 and 10% of the original counts) by randomly removing events from the original LM data. All data were reconstructed using the vendor-specific e7-tools with standard OSEM only, with OSEM plus resolution recovery (PSF). The reconstructions were repeated with added TOF (TOF) and PSF+TOF. The benefit of TOF together with the reduced count levels was evaluated by calculating the gains in signal-to-noise ratio (SNR) in the liver and contrast-to-noise ratio (CNR) in all PET-positive lesions before and after TOF employed at every simulated reduced count level. Finally, the PSF+TOF images at 50, 75 and 100% of counts were evaluated clinically on a 5-point scale by three nuclear medicine physicians. RESULTS: The visual inspection of the reconstructed images did not reveal significant differences in image quality between 75 and 100% count levels for PSF+TOF. The improvements in SNR and CNR were the greatest for TOF reconstruction and PSF combined. Both SNR and CNR gains did increase linearly with the patients BMI for both OSEM only and PSF reconstruction. These benefits were observed until reducing the counts to 50 and 35% for SNR and CNR, respectively. CONCLUSIONS: The benefit of using TOF was noticeable when using 50% or greater of the counts when evaluating the CNR and SNR. For [18F]FDG-PET/CT, whole-body paediatric imaging the injected activity can be reduced to 75% of the original dose without compromising PET image quality.

A multi institutional comparison of imaging dose and technique protocols for neonatal chest radiography.

INTRODUCTION: The focus on paediatric radiation dose reduction supports reevaluation of paediatric imaging protocols. This is particularly important in the neonates where chest radiographs are frequently requested to assess respiratory illness and line placement. This study aims to assess the impact of neonatal chest radiographic protocols on patient dose in four hospitals in different countries. METHODS: Exposure parameters, collimation, focus to skin distance (FSD) and radiation dose from 200 neonatal chest radiographs were registered prospectively. Inclusion criteria consisted of both premature and full-term neonates weighing between 1000 and 5000 g. Only data from the examinations meeting diagnostic criteria and approved for the clinical use were included. Radiation dose was assessed using dose area product (DAP). RESULTS: The lowest DAP value (4.58 mGy cm2) was recorded in the Norwegian hospital, employing a high kVp, low mAs protocol using a DR system. The Canadian hospital recorded the highest DAP (9.48), using lower kVp and higher mAs with a CR system, including the addition of a lateral projection. The difference in the mean DAP, weight, field of view (FOV) and kVp between the hospitals is statistically significant (p < 0.001). CONCLUSION: Use of non-standardised imaging protocols in neonatal chest radiography results in differences in patient dose across hospitals included in the study. Using higher kVp, lower mAs and reducing the number of lateral projections to clinically relevant indications result in a lower DAP measured in the infant sample studied. Further studies to examine image quality based on exposure factors and added filtration are recommended. IMPLICATIONS FOR PRACTICE: Reevaluation of paediatric imaging protocols presents an opportunity to reduce patient dose in a population with increased sensitivity to ionising radiation.

Pediatric chest x-ray in covid-19 infection.

BACKGROUND: The outbreak of COVID-19 has become pandemic. Pediatric population has been less studied than adult population and prompt diagnosis is challenging due to asymptomatic or mild episodes. Radiology is an important complement to clinical and epidemiological features. OBJECTIVE: To establish the most common CXR patterns in children with COVID-19, evaluate interobserver correlation and to discuss the role of imaging techniques in the management of children. MATERIALS AND METHODS: Forty-four patients between 0 and 16 years of age with confirmed SARS-Cov-2 infection and CXR were selected. Two paediatric radiologists independently evaluated the images and assessed the type of abnormality, distribution and evolution when available. RESULTS: Median age was 79.8 months (ranging from 2 weeks to 16 years of age). Fever was the most common symptom (43.5 %). 90 % of CXR showed abnormalities. Peribronchial cuffing was the most common finding (86.3 %) followed by GGOs (50 %). In both cases central distribution was more common than peripheral. Consolidations accounted for 18.1 %. Normal CXR, pleural effusion, and altered cardiomediastinal contour were the least common. CONCLUSION: The vast majority of CXR showed abnormalities in children with COVID-19. However, findings are nonspecific. Interobserver correlation was good in describing consolidations, normal x-rays and GGOs. Imaging techniques have a role in the management of children with known or suspected COVID-19, especially in those with moderate or severe symptoms or with underlying risk factors.

MRπ: Inside the meat pie.

Meat pies have been adopted as one of Australia's favourite foods, and considered an icon by many. The hand-held convenience of the pie has made them a culinary necessity while watching sport, also beloved in Australia. An enduring question about the meat pie is what exactly is inside. This can be difficult to ascertain by digital, ocular or oral exploration. In this study we use MR imaging to study the contents of some of Australia's best loved pies.

Activity estimation and biokinetic analysis of 99mTc-DMSA in renal infant patients using a gamma camera.

Biokinetic data from the administration of radiopharmaceuticals is essential in nuclear medicine dosimetry. It has particular significance in children, as their metabolism is very different from adults. Biokinetic models for paediatric patients could therefore need to be adapted to better reflect their absorption, retention and excretion functions, when compared to adults. Obtaining quality in vivo infant or paediatric biokinetic data is then essential to improve the available reference models, which in turn can lead to the optimization of paediatric procedures and protocols in clinical practice. This study analyses the biokinetic behaviour of 99mTc-dimercaptosuccinic acid (DMSA), in 8 infants aged 4 months to 2 years old, through an imaging study using a gamma camera, and compares the obtained values with those obtained with the reference ICRP biokinetic model. The in vivo data was treated using an adapted methodology from the MIRD 16 pamphlet. Activity curves for the liver, the kidney and the whole body, were built, and new effective absorption, retention and excretion half-lives were estimated, and compared with the reference biokinetic parameters of ICRP 128. The obtained residence time in the kidneys of 2.56 h, has a deviation of 30.8% to the ICRP 128 value of 3.70 h. The obtained maximum uptake in the kidneys was of 0.22/A0, which compares to the value of 0.31/A0 for ICRP. The obtained biokinetic parameters were used to estimate the absorbed dose. The obtained dose values are smaller than the reference ICRP 128 ones by 32.1% in the kidneys, and 18.4% in the liver.

Benefit-risk communication in paediatric imaging: What do referring physicians, radiographers and radiologists think, say and do?

INTRODUCTION: To assess how referrers and practitioners disclose benefit-risk information about medical imaging examinations to paediatric patients and their parents/guardians; to gauge their confidence in doing so; and to seek their opinion about who is responsible for disclosing such information. METHODS: This study followed on from a previously published study, with a questionnaire distributed in staggered phases to 146 radiographers, 22 radiology practitioners, 55 emergency physicians and 43 paediatricians at a primary paediatric referral centre in Malta. The questionnaire sought details about referrers' and practitioners' practice of disclosing benefit-risk information, as well as their opinion about their confidence and responsibility to do so. RESULTS: An overall response rate of 63.2% (168/266) was achieved. Most referrers and practitioners would generally explain the purpose of the imaging examination, with fewer providing benefit-risk information. The content and the approach adopted to communicate benefit-risk information varied, at times considerably. While 75% (123/164) felt that the responsibility to provide benefit-risk information was a shared one between referrers and practitioners, only 32.1% (53/165) reported a high level of confidence in their own ability to do so. CONCLUSIONS: Our findings highlight potential knowledge and skills gaps amongst local referrers and practitioners. This needs addressing so as to ensure that paediatric patients and their parents/guardians are provided with adequate, reassuring and consistent information. Additionally, we recommend that local referrers and practitioners come together and develop a consensus document that can offer guidance on how to go about discussing the benefits and risks of paediatric imaging examinations.