Subventricular zone stem cell niche injury is associated with intestinal perforation in preterm infants and predicts future motor impairment.

Brain injury is highly associated with preterm birth. Complications of prematurity, including spontaneous or necrotizing enterocolitis (NEC)-associated intestinal perforations, are linked to lifelong neurologic impairment, yet the mechanisms are poorly understood. Early diagnosis of preterm brain injuries remains a significant challenge. Here, we identified subventricular zone echogenicity (SVE) on cranial ultrasound in preterm infants following intestinal perforations. The development of SVE was significantly associated with motor impairment at 2 years. SVE was replicated in a neonatal mouse model of intestinal perforation. Examination of the murine echogenic subventricular zone (SVZ) revealed NLRP3-inflammasome assembly in multiciliated FoxJ1+ ependymal cells and a loss of the ependymal border in this postnatal stem cell niche. These data suggest a mechanism of preterm brain injury localized to the SVZ that has not been adequately considered. Ultrasound detection of SVE may serve as an early biomarker for neurodevelopmental impairment after inflammatory disease in preterm infants.

KeyLoop: Mechanical Retraction of the Abdominal Wall for Gasless Laparoscopy.

Background. Despite favorable outcomes of laparoscopic surgery in high-income countries, its implementation in low- and middle-income countries (LMICs) is challenging given a shortage of consumable supplies, high cost, and risk of power outages. To overcome these barriers, we designed a mechanical retractor that provides vertical tension on the anterior abdominal wall. Methods. The retractor design is anatomically and mathematically optimized to provide exposure similar to traditional gas-based insufflation methods. Anatomical data from computed tomography scans were used to define retractor size. The retractor is constructed of biocompatible stainless steel rods and paired with a table-mounted lifting system to provide 5 degrees of freedom. Structural integrity was assessed through finite element analysis (FEA) and load testing. Functional testing was performed in a laparotomy model. Results. A user guide based on patient height and weight was created to customize retractor size, and 4 retractor sizes were constructed. FEA data using a 13.6 kg mass (15 mm Hg pneumoperitoneum) show a maximum of 30 mm displacement with no permanent deformation. Physical load testing with applied weight from 0 to 13.6 kg shows a maximum of 60 mm displacement, again without permanent deformation. Retraction achieved a 57% larger field of view compared to an unretracted state in a laparotomy model. Conclusions. The KeyLoop retractor maintains structural integrity, is easily sterilized, and can be readily manufactured, making it a viable alternative to traditional insufflation methods. For surgeons and patients in LMICs, the KeyLoop provides a means to increase access to laparoscopic surgery.

Advances in the Diagnosis and Management of Neonatal Sarcomas.

Neonatal sarcomas comprise a heterogeneous group of rare soft tissue neoplasms that present unique diagnostic and therapeutic challenges. Recent advances in molecular profiling have improved diagnostic capabilities and reveal novel therapeutic targets. Clinical trials demonstrate differences in behavior between sarcoma subtypes that allow for better clinical management. Surgical resection has been replaced with a multimodal approach that includes chemotherapy and radiotherapy. Despite these advances, neonates with sarcoma continue to fare worse than histologically similar sarcomas in older children, likely reflecting differences in tumor biology and the complexities of neonatal medicine. This review focuses on recent advances in managing neonatal sarcomas.

Imaging of childhood urologic cancers: current approaches and new advances.

Urologic tumors make up approximately 10% of all pediatric cancers, and include a variety of different histologies and imaging considerations. In this review, we discuss standard radiologic approaches for children with tumors arising in the genitourinary system, and identify important ways in which imaging affects the differential diagnosis, preoperative planning, and staging of these tumors. In addition, we provide an update on strategies to reduce the time of imaging, which may obviate the need for sedation in younger patients. Efforts to reduce a patient's overall radiation exposure and subsequent risk of second malignancy are also detailed, including recent work on surveillance imaging following completion of therapy. Finally, we highlight new techniques such as radiomics that are now being investigated for patients with these malignancies.

Pediatric Hepatoblastoma, Hepatocellular Carcinoma, and Other Hepatic Neoplasms: Consensus Imaging Recommendations from American College of Radiology Pediatric Liver Reporting and Data System (LI-RADS) Working Group.

Appropriate imaging is imperative in evaluating children with a primary hepatic malignancy such as hepatoblastoma or hepatocellular carcinoma. For use in the adult patient population, the American College of Radiology created the Liver Imaging Reporting and Data System (LI-RADS) to provide consistent terminology and to improve imaging interpretation. At present, no similar consensus exists to guide imaging and interpretation of pediatric patients at risk for developing a liver neoplasm or how best to evaluate a pediatric patient with a known liver neoplasm. Therefore, a new Pediatric Working Group within American College of Radiology LI-RADS was created to provide consensus for imaging recommendations and interpretation of pediatric liver neoplasms. The article was drafted based on the most up-to-date existing information as interpreted by imaging experts comprising the Pediatric LI-RADS Working Group. Guidance is provided regarding appropriate imaging modalities and protocols, as well as imaging interpretation and reporting, with the goals to improve imaging quality, to decrease image interpretation errors, to enhance communication with referrers, and to advance patient care. An expanded version of this document that includes broader background information on pediatric hepatocellular carcinoma and rationale for recommendations can be found in Appendix E1 (online).

Expanding the Concept of Diagnostic Reference Levels to Noise and Dose Reference Levels in CT.

OBJECTIVE. Diagnostic reference levels were developed as guidance for radiation dose in medical imaging and, by inference, diagnostic quality. The objective of this work was to expand the concept of diagnostic reference levels to explicitly include noise of CT examinations to simultaneously target both dose and quality through corresponding reference values. MATERIALS AND METHODS. The study consisted of 2851 adult CT examinations performed with scanners from two manufacturers and two clinical protocols: abdominopelvic CT with IV contrast administration and chest CT without IV contrast administration. An institutional informatics system was used to automatically extract protocol type, patient diameter, volume CT dose index, and noise magnitude from images. The data were divided into five reference patient size ranges. Noise reference level, noise reference range, dose reference level, and dose reference range were defined for each size range. RESULTS. The data exhibited strong dependence between dose and patient size, weak dependence between noise and patient size, and different trends for different manufacturers with differing strategies for tube current modulation. The results suggest size-based reference intervals and levels for noise and dose (e.g., noise reference level and noise reference range of 11.5-12.9 HU and 11.0-14.0 HU for chest CT and 10.1-12.1 HU and 9.4-13.7 HU for abdominopelvic CT examinations) that can be targeted to improve clinical performance consistency. CONCLUSION. New reference levels and ranges, which simultaneously consider image noise and radiation dose information across wide patient populations, were defined and determined for two clinical protocols. The methods of new quantitative constraints may provide unique and useful information about the goal of managing the variability of image quality and dose in clinical CT examinations.

Free-breathing unsedated MRI in children: Justification and techniques.

One of the more common and important challenges in the imaging of children is minimizing image degradation caused by motion. This is especially important in MRI, which is often preferable in the pediatric population due to better tissue characterization and lack of ionizing radiation. However, due to the length of time needed for most examinations, MRI is among the most sensitive to disruption by patient motion. Traditionally, deep conscious sedation or general anesthesia was the most common method of reducing motion in children who are unable or unwilling to follow direction. As the drawbacks and risks of anesthesia in children become more known and accepted, the development and optimization of means of mitigating motion and anxiety in children without the use of sedation or anesthesia becomes more urgent. In this article we describe the risks of sedation in the pediatric population and explore current methods of reducing both patient anxiety and imaging degradation from motion in the unsedated, free-breathing child. Level of Evidence: 5 Technical Efficacy: Stage 5 J. Magn. Reson. Imaging 2019;50:365-376.

A Simulation Paradigm for Evaluation of Subtle Liver Lesions at Pediatric CT: Performance and Confidence.

Purpose: To create and validate a systematic observer performance platform for evaluation of simulated liver lesions at pediatric CT and to test this paradigm to measure the effect of radiation dose reduction on detection performance and reader confidence. Materials and Methods: Thirty normal pediatric (from patients aged 0-10 years) contrast material-enhanced, de-identified abdominal CT scans obtained from July 1, 2012, through July 1, 2016, were retrospectively collected from the clinical database. The study was exempt from institutional review board approval. Zero to three simulated, low-contrast liver lesions (≤6 mm) were digitally inserted by using software, and noise was added to simulate reductions in volume CT dose index (representing radiation dose estimation) of 25% and 50%. Pediatric, abdominal, and resident radiologists (three of each) reviewed 90 data sets in three sessions using an online interface, marking each lesion location and rating confidence (scale, 0-100). Statistical analysis was performed by using software. Results: Mixed-effects models revealed a significant decrease in detection sensitivity as radiation dose decreased (P < .001). The mean confidence of the full-dose and 25% dose reduction examinations was significantly higher than that of the 50% dose reduction examinations (P = .011 and .012, respectively) but not different from one another (P = .866). Dose was not a significant predictor of time to complete each case, and subspecialty was not a significant predictor of sensitivity or false-positive results. Conclusion: Sensitivity for lesion detection significantly decreased as dose decreased; however, confidence did not change between the full-dose and 25% reduced-dose scans. This suggests that readers are unaware of this decrease in performance, which should be accounted for in clinical dose reduction efforts.Keywords: Abdomen/GI, CT, Liver, Observer Performance, Pediatrics, Perception Image© RSNA, 2019.

Current utilization and procedural practices in pediatric whole-body MRI.

BACKGROUND: Whole-body magnetic resonance imaging (MRI) is an evolving and increasingly powerful imaging tool with a variety of applications in the pediatric patient population. Variability exists among radiology practices in how this MRI tool is used and how it is performed. OBJECTIVE: Our objective was to gain an improved understanding of technical and utilization practices in pediatric whole-body MRI across North America by exploring indications for exam performance, determining referral patterns, and assessing technical protocols and procedures. MATERIALS AND METHODS: A 19-question survey was generated in Survey Monkey and distributed in 2016 to the Society for Pediatric Radiology membership. The survey asked questions that included practice type, imaging modality preferences for diseases commonly evaluated with whole-body MRI, MRI field strength and sequence selection, and billing practices. RESULTS: Data were obtained from 62 unique responses to the survey, representing 471 physicians. The majority (93%) practice in an academic institution or private practice with academic affiliation and most practices have utilized whole-body MRI for less than 6 years. Whole-body MRI is performed in pediatric patients 0 to 18 years of age, and was the preferred imaging modality for diagnosis/staging/follow-up in neurofibromatosis, type 1 (75%), chronic recurrent multifocal osteomyelitis (CRMO) (74%), cancer predisposition syndromes (75%), vasculopathies (50%) and disseminated/multifocal infection (49%). The most commonly utilized sequences are coronal short tau inversion recovery (STIR) (90%), coronal T1 with or without fat saturation (65%), and axial diffusion-weighted imaging (DWI) (48%). No preference was shown for either 1.5-T or 3-T systems. Wide variability was seen in preference for billing code utilization, though the majority use chest/abdomen/pelvis (57%) or unlisted MRI (37%) codes. CONCLUSION: Radiology practitioners - represented by the Society for Pediatric Radiology pediatric radiologists - are using whole-body MRI in the imaging care of pediatric patients for a variety of indications. Survey results reveal some variability in exam utilization and technical performance practices among those pediatric radiologists who perform whole-body MRI.

Children with Cough and Fever: Up-to-date Imaging Evaluation and Management.

Cough and fever in infants and children are frequent but nonspecific symptoms. Several usual differential diagnoses are under consideration and imaging is often necessary to help arrive at an accurate diagnosis and ensure proper management. A broad spectrum of underlying disorders may be present. Radiologists must remain cognizant of the potential for immune dysfunction and underlying structural abnormalities. A clear understanding of up-to-date imaging evaluation recommendations and characteristic imaging features can assist radiologists and clinicians in arriving at the most accurate diagnosis in a timely manner and help ensure proper management and necessary follow-up imaging assessment.

JOURNAL CLUB: Can Coronal STIR Be Used as Screening for Acute Nontraumatic Hip Pain in Children?

OBJECTIVE: The objective of this study is to evaluate whether coronal STIR MRI can be used as a screening test for nontraumatic acute hip pain in children. MATERIALS AND METHODS: From 2008 to 2012, we identified all patients younger than 18 years at our tertiary care facility who underwent pelvic MRI including coronal STIR for the following indications: acute hip pain, limping, or refusal to bear weight. Patients with a history of trauma were excluded. Each MR image was independently reviewed by four radiologists who were blinded to the clinical outcome. After first reviewing the coronal STIR images only, they then reviewed the full MRI studies in a random order different from that used for review of the coronal STIR images. The sensitivity and specificity of STIR-only images in identifying the presence of abnormality and specific diagnoses were calculated, with the full MRI study considered as the reference standard. Kappa values were calculated for STIR-only and full MRI studies. RESULTS: A total of 127 patients (67 female patients and 60 male patients; median age, 9 years; range, 5 months to 17 years) were identified. The most common abnormalities (calculated as the mean of frequency values noted by four readers) were hip effusion (52%; range, 46-58%), osteomyelitis (42%; range, 29-48%), and myositis (32%; range, 20-40%). For the detection of any abnormality, STIR-only images had a mean sensitivity of 95% and a mean specificity of 67%. For approximately one-third of STIR-only studies with true-positive results, additional abnormalities were found on full MRI studies. CONCLUSION: Coronal STIR imaging of the pelvis has high sensitivity (95%) in the detection of abnormalities associated with acute nontraumatic hip pain in children, but it often misses additional abnormalities.

Structured Reporting of Magnetic Resonance Enterography for Pediatric Crohn's Disease: Effect on Key Feature Reporting and Subjective Assessment of Disease by Referring Physicians.

PURPOSE: To objectively compare the content of structured reports (SR) vs nonstructured reports (NSR) for magnetic resonance enterography (MRE) of pediatric patients with Crohn's disease, and to evaluate referring clinicians' subjective assessment of reports. METHODS: This institutional review board-approved, Health Insurance Portability and Accountability Act-compliant retrospective study included 25 pediatric subjects (15 male, 10 female; mean age = 14 years [range: 9-18 years]) with Crohn's disease imaged with MRE. Three radiologists independently interpreted all examinations using both NSR and SR, separated by 4 weeks. Reports were assessed for documentation of the presence or absence of 15 key reporting features. A total of 30 reports (15 NSR [5 per reader] and 15 SR [5 per reader]) were randomly selected for review by 3 referring physicians, who subjectively evaluated the reports independently. RESULTS: NSR documented the presence or absence of 7.7 ± 2.5 key features, whereas SR documented 14.0 ± 0.8 features (P < 0.001). SR resulted in increased documentation of 12 of 15 features including stricture (P < 0.001), fistula (P < 0.001), fluid collection (P = 0.003), and perianal disease (P < 0.001). Referring physicians preferred SR regarding ease of information extraction, clarity of anatomy, and ability to identify disease phenotype (P < 0.01 for each). CONCLUSION: The use of structured reporting in describing pediatric Crohn's disease, MRE resulted in significantly increased reporting of key features. Referring clinicians also demonstrated a subjective preference for SR.

Pediatric whole-body MRI: A review of current imaging techniques and clinical applications.

There are many congenital, neoplastic, inflammatory, and infectious processes in the pediatric patient for which whole-body imaging may be of benefit diagnostically and prognostically. With recent improvements in magnetic resonance imaging (MRI) hardware and software and resultant dramatically reduced scan times, imaging of the whole body with MRI has become a much more practicable technique in children. Whole-body MRI can provide a high level of soft tissue and skeletal detail while avoiding the exposure to ionizing radiation inherent to computed tomography and nuclear medicine imaging techniques. This article reviews the more common current whole-body MRI techniques in children and the primary pathologies for which this imaging modality may be most useful to the radiologists and referring clinicians. J. MAGN. RESON. IMAGING 2016;44:783-793.

Gastrointestinal Tract Perforation in the Newborn and Child: Imaging Assessment.

Gastrointestinal tract perforation can arise from various underlying etiologies ranging from congenital causes to ingested foreign bodies in the pediatric patient population. Imaging assessment in patients with suspected gastrointestinal tract perforation plays a central role in making the diagnosis and follow-up evaluation. This article reviews the more common etiologies of gastrointestinal tract perforation in pediatric patients, their imaging manifestations, and strategies for imaging assessment to assist the radiologist in arriving at a timely and accurate diagnosis.

Size of sentinel node tumor deposits and extent of axillary lymph node involvement: which breast cancer patients may benefit from less aggressive axillary dissections?

BACKGROUND: In most breast cancer series, nearly 30% to 40% of all patients are sentinel node positive; however, in a large proportion of these, the disease is limited to three or fewer positive nodes. On the basis of these observations, the object of this study is to identify a subset of patients who might benefit from a less aggressive axillary dissection, without compromising staging or local disease control. We reviewed known clinicopathologic variables associated with a higher risk for axillary metastasis in 467 patients who underwent sentinel node mapping at our institution. We then compared the incidence of these variables in patients with N1a versus N2-3 stage disease. RESULTS: Although the presence of lymphvascular invasion in the primary tumor and extracapsular extension of tumor in the sentinel node were statistically significantly different between N1a and N2-3 patients (P < .025 and P < .01, respectively), the variable that most reliably separated N1a from N2-3 patients was the size of the tumor deposits in the sentinel node (P < .001). All patients with sentinel node tumor deposits

Ultrasound-guided fine-needle aspiration of clinically negative lymph nodes versus sentinel node mapping in patients at high risk for axillary metastasis.

BACKGROUND: Sonographically directed fine-needle aspiration is a less invasive and less costly alternative to sentinel node (SN) mapping in breast cancer patients at high risk for metastatic disease but with clinically negative axillae. METHODS: Radiographic, cytological, and histological diagnostic data on breast primary tumors from 114 consecutive SN candidates were prospectively assessed for clinicopathologic variables associated with an increased incidence of axillary metastases. Patients in whom these variables were identified underwent sonographic examination of their axillae followed by fine-needle aspiration when abnormal nodes were detected. SN mapping was performed in patients with normal axillary sonogram results or negative cytological results. Patients with positive cytological results proceeded to complete axillary dissection. Final axillary histological outcomes from patients not meeting the high-risk criteria were recorded. Additionally, a cost analysis was performed in which the costs of ultrasonography and ultrasound-guided fine-needle aspiration of the axilla were compared with those of SN mapping. RESULTS: According to our selection criteria, a third of the patients with clinically negative axillae (37 of 114; 32%) were considered at high risk for axillary metastases. Fifty-nine percent of these patients (22 of 37) had metastatic disease on final histological analysis. Forty percent (15 of 37) of high-risk patients were spared SN mapping, with a reduction in health care costs of 20% in this patient population. Eighty-seven percent of patients not meeting high-risk criteria were SN negative. CONCLUSIONS: This study suggests that in patients at increased risk for axillary metastases, the use of sonographic evaluation of the axilla in combination with fine-needle aspiration is not only clinically justified, but also cost-effective.