Pearls and Pitfalls in Diagnosing Pediatric Urinary Bladder Masses

Urinary bladder masses are rare in children, and the associated histologic features and prognoses in this population are different from those in adults. Most children with urinary bladder masses present with lower urinary tract symptoms, which may include hematuria, dysuria, frequent urination, and urgency to urinate. However, some of these masses may be identified incidentally or involve generic symptoms such as abdominal distention. In general, pediatric bladder tumors can be divided into those that originate from the bladder epithelium, known as urothelial neoplasms, and mesenchymal bladder neoplasms, which are more prevalent. The most common bladder malignancy in children is a rhabdomyosarcoma, whereas the most common benign bladder lesion in the pediatric population is a papillary urothelial neoplasm of low malignant potential (PUNLMP). The first-line imaging tool for assessing bladder lesions is ultrasonography, which may be followed by a cross-sectional imaging examination such as computed tomography or magnetic resonance imaging if the origin of the mass is unclear or if distant spread is suspected. Although imaging may enable the radiologist to suggest a differential diagnosis based on lesion location and patient age, tissue biopsy generally is required to identify the exact pathologic entity. This is usually performed at cystoscopy and may be curative in cases in which the lesion is small and has low recurrence potential. Knowledge of the clinical, histopathologic, and imaging features of common bladder neoplasms is essential, as it can aid in preventing imaging pitfalls. These may include the misinterpretation of either a pelvic mass as arising from the bladder or a bladder mass as arising from the pelvis, and interpreting an inflammatory mass or bladder detritus as a neoplasm

Imaging of late complications of cancer therapy in children

Long-term survival after childhood cancer has improved dramatically over recent decades but survivors face lifelong risks of adverse health effects. Many of these chronic conditions are a direct result of previous therapeutic exposures. Compared to their siblings, survivors face a greater than 8-fold increase in relative risk of severe or life-threatening medical conditions; the most significant of these include second malignancies and cardiovascular and pulmonary diseases. Imaging can play a key role in identifying and characterizing such complications, which can be reasonably predicted with knowledge of the child’s treatment. This article highlights the varied radiologic presentations and features seen in late cancer-therapy-related conditions

Hepatobiliary and pancreatic imaging in children—techniques and an overview of non-neoplastic disease entities

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

Magnetic resonance imaging in children: common problems and possible solutions for lung and airways imaging

Pediatric chest MRI is challenging. High-resolution scans of the lungs and airways are compromised by long imaging times, low lung proton density and motion. Low signal is a problem of normal lung. Lung abnormalities commonly cause increased signal intenstities. Among the most important factors for a successful MRI is patient cooperation, so the long acquisition times make patient preparation crucial. Children usually have problems with long breath-holds and with the concept of quiet breathing. Young children are even more challenging because of higher cardiac and respiratory rates giving motion blurring. For these reasons, CT has often been preferred over MRI for chest pediatric imaging. Despite its drawbacks, MRI also has advantages over CT, which justifies its further development and clinical use. The most important advantage is the absence of ionizing radiation, which allows frequent scanning for short- and long-term follow-up studie

Delineation of Tumor Habitats based on Dynamic Contrast Enhanced MRI

Tumor heterogeneity can be elucidated by mapping subregions of the lesion with differential imaging characteristics, called habitats. Dynamic Contrast Enhanced (DCE-)MRI can depict the tumor microenvironments by identifying areas with variable perfusion and vascular permeability, since individual tumor habitats vary in the rate and magnitude of the contrast uptake and washout. Of particular interest is identifying areas of hypoxia, characterized by inadequate perfusion and hyper-permeable vasculature. An automatic procedure for delineation of tumor habitats from DCE-MRI was developed as a two-part process involving: (1) statistical testing in order to determine the number of the underlying habitats; and (2) an unsupervised pattern recognition technique to recover the temporal contrast patterns and locations of the associated habitats. The technique is examined on simulated data and DCE-MRI, obtained from prostate and brain pre-clinical cancer models, as well as clinical data from sarcoma and prostate cancer patients. The procedure successfully identified habitats previously associated with well-perfused, hypoxic and/or necrotic tumor compartments. Given the association of tumor hypoxia with more aggressive tumor phenotypes, the obtained in vivo information could impact management of cancer patients considerably