New frontiers in pediatric oncologic imaging

Artificial intelligence applications for pediatric oncology imaging

Machine learning algorithms can help to improve the accuracy and efficiency of cancer diagnosis, selection of personalized therapies and prediction of long-term outcomes. Artificial intelligence (AI) describes a subset of machine learning that can identify patterns in data and take actions to reach pre-set goals without specific programming. Machine learning tools can help to identify high-risk populations, prescribe personalized screening tests and enrich patient populations that are most likely to benefit from advanced imaging tests. AI algorithms can also help to plan personalized therapies and predict the impact of genomic variations on the sensitivity of normal and tumor tissue to chemotherapy or radiation therapy. The two main bottlenecks for successful AI applications in pediatric oncology imaging to date are the needs for large data sets and appropriate computer and memory power. With appropriate data entry and processing power, deep convolutional neural networks (CNNs) can process large amounts of imaging data, clinical data and medical literature in very short periods of time and thereby accelerate literature reviews, correct diagnoses and personalized treatments. This article provides a focused review of emerging AI applications that are relevant for the pediatric oncology imaging community.

Reconstruction of a severe mandibular pathological fracture caused by Langerhans cell histiocytosis using a free fibula osteocutaneous flap:a case report

Langerhans cell histiocytosis (LCH) is a rare disease in which Langerhans cells, which are bone marrow-derived antigen-presenting cells, proliferate in single or multiple organs. We successfully treated a patient with unifocal LCH of the mandible with malocclusion due to a severe pathological fracture, using reconstruction with a vascularised free bone.

Safety of contrast-enhanced ultrasound in children for non-cardiac applications: a review by the Society for Pediatric Radiology (SPR) and the International Contrast Ultrasound Society (ICUS)

The practice of contrast-enhanced ultrasound in children is in the setting of off-label use or research. The widespread practice of pediatric contrast-enhanced US is primarily in Europe. There is ongoing effort by the Society for Pediatric Radiology (SPR) and International Contrast Ultrasound Society (ICUS) to push for pediatric contrast-enhanced US in the United States. With this in mind, the main objective of this review is to describe the status of US contrast agent safety in non-cardiac applications in children. The five published studies using pediatric intravenous contrast-enhanced US comprise 110 children. There is no mention of adverse events in these studies. From a European survey 948 children can be added. In that survey six minor adverse events were reported in five children. The intravesical administration of US contrast agents for diagnosis of vesicoureteric reflux entails the use of a bladder catheter. Fifteen studies encompassing 2,951 children have evaluated the safety of intravesical US contrast agents in children. A European survey adds 4,131 children to this group. No adverse events could be attributed to the contrast agent. They were most likely related to the bladder catheterization. The existing data on US contrast agent safety in children are encouraging in promoting the widespread use of contrast-enhanced US.

Neuroblastoma

Neuroblastoma is a common malignancy of infancy and early childhood. The difference in the outcomes for patients with these neoplasms is striking. Infants younger than one year have a good prognosis, even in the presence of metastatic disease, whereas older patients with metastatic disease fare poorly even when treated with aggressive therapy. The noninvasive nature of diagnostic sonography has allowed it to play a major role in the early detection and treatment of neuroblastoma. This early sonographic detection, in conjunction with early postnatal surgical intervention, has greatly improved the prognosis of infants born with neuroblastoma.

Ultrasound contrast media in paediatric patients: is it an off-label use? Regulatory requirements and radiologist's liability

The use of ultrasound contrast media is yet to be validated in children. The rare reports in the scientific literature denote their "sporadic" and "experimental" use. Their most likely use is in the setting of off-label prescription of medications. As there are still no guidelines available in Italy for the off-label use of medications, we aim to define the duties, obligations and liability of ultrasound radiologists according to the laws in force.

Regional and whole-body imaging in pediatric oncology

The goals of tumor imaging include tumor detection, tumor characterization and differential diagnosis, imaging-guided biopsy, evaluation of tumor extent and staging, assessment of treatment responses, and surveillance for residual tumor or tumor recurrence. In clinical practice, various combinations of imaging modalities are used to achieve these goals. Recently introduced tumor imaging methods, such as diffusion MRI, perfusion MRI, whole-body MRI, and positron emission tomography (PET-CT), have shown promising results. Depending on tumor type and management plan, imaging protocols for children should be individually optimized to achieve the shortest examination time, the highest image quality, the lowest risk, and maximum clinical benefits. In this article, the roles of regional and whole-body tumor imaging will be reviewed, and several important issues related to recent technical developments will be discussed.

Molecular ultrasound imaging and its potential for paediatric radiology

US is a low-cost, real-time imaging modality that is the most used diagnostic tool in paediatric radiology. Reasons include the improved US image quality in children as compared to adults and the demand for avoiding X-rays as much as possible because children are more sensitive to radiation than adults. Stabilized microbubbles have been approved as US contrast agents for adults and show great potential in improving the diagnostic accuracy for many diseases. Initial studies show that in paediatric radiology contrast-enhanced US could also be beneficial for more than just the diagnosis of vesicoureteral reflux, if US contrast agents were approved for children. Molecular US imaging utilizes microbubbles conjugated to biomolecules that target intravascular disease-specific molecules. Many preclinical studies show that molecular US imaging is a highly sensitive tool to detect neovascularisation, inflammation and cardiovascular diseases. Its main advantages are the higher informative value, the longer persistence of the label at the target lesion and the chance to work with lower contrast agent dosages. Now, clinical translation of molecular US appears at the horizon. This review article reports on the current status of molecular US imaging and discusses its potential for paediatric radiology.

A rabbit bone tumor model for high-intensity focused ultrasound therapy

The incidence of malignant bone tumor increases every year. Because the application of high-intensity focused ultrasound (HIFU) for the treatment of bone tumors is still at a nascent stage, it is essential to study the effectiveness of this technique in ideal animal models in order to obtain a beneficial reference for imaging studies. In this study, we established a VX2 malignant bone tumor model and evaluated this model by contrast-enhanced sonography and magnetic resonance imaging (MRI). The results show that all tumors were enhanced after injection of SonoVue. A contrast-enhanced MRI scan revealed obvious enhancement within the tumors. Histological examination revealed the presence of a large number of tumor cells. The model can serve as an ideal experimental model for the study of HIFU therapy in the treatment of malignant bone tumors and as a reference for imaging studies during follow-ups.

MR imaging of primary bone tumors and tumor-like conditions in children

This article provides a review of the MR imaging features of the major primary malignant and benign bone tumors and tumorlike conditions encountered in the pediatric population. Malignant tumors discussed include osteosarcoma, Ewing sarcoma, chondrosarcoma, lymphoma, and malignant fibrous histiocytoma. Benign lesions discussed include simple bone cysts, aneurysmal bone cysts, giant cell tumor, osteochondroma, enchondroma, chondroblastoma, osteoid osteoma, osteoblastoma, nonossifying fibroma, fibrous dysplasia, osteofibrous dysplasia, hemangioma, and histiocytosis. The use of MR imaging in the diagnosis of these lesions is discussed, and the text is enhanced with imaging examples of the lesions.