Endemic mycoses in children in North America: a review of radiologic findings.

Clinically significant endemic mycoses (fungal infections) in the United States (U.S.) include Blastomyces dermatitidis, Histoplasma capsulatum, and Coccidioides immitis/posadasii. While the majority of infections go clinically unnoticed, symptomatic disease can occur in immunocompromised or hospitalized patients, and occasionally in immune-competent individuals. Clinical manifestations vary widely and their diagnosis may require fungal culture, making the rapid diagnosis a challenge. Imaging can be helpful in making a clinical diagnosis prior to laboratory confirmation, as well as assist in characterizing disease extent and severity. In this review, we discuss the three major endemic fungal infections that occur in the U.S., including mycology, epidemiology, clinical presentations, and typical imaging features with an emphasis on the pediatric population.

Imaging button battery ingestions and insertions in children: a 15-year single-center review.

BACKGROUND: Recent studies have shown an increase in morbidity associated with button battery ingestions in children. OBJECTIVE: To perform a comprehensive, imaging-focused review of all patients with confirmed button battery ingestions/insertions imaged at our institution in the last 15 years. MATERIALS AND METHODS: Radiology reports from Jan. 1, 2000, to July 12, 2015, were searched for the terms "battery" and "batteries." Confirmed cases of battery ingestion/insertion for which images were available were reviewed. Cases were reviewed for imaging studies performed, imaging findings, patient demographics, clinical history and management. Two pediatric gastroenterologists reviewed endoscopic images and graded mucosal injuries in selected cases. RESULTS: Two hundred seventy-six cases were reviewed. All patients were imaged with radiography, 19 with fluoroscopy (6.8%), and 4 with CT (1.4%). Batteries retained in the esophagus (n = 27, 9.8%) were larger in diameter on average than those that had passed distally (22.1 ± 3.3 mm vs. 13.7 ± 1.6 mm, P<0.0001). Battery diameter ≥20 mm was associated with esophageal impaction (P<0.0001) and higher grade esophageal injury (P<0.0001). Mean battery diameter was greater for patients with grade 1 or higher mucosal injury than for patients with no mucosal injury (22.1 ± 2.1 mm vs. 14.7 ± 4.5 mm, P<0.0001). Sixteen percent (4/25) of patients with grade ≥1 esophageal injury had batteries in the stomach on initial imaging. Five patients (1.8%) had serious clinical complications (e.g., esophageal perforation, tracheoesophageal fistula). CONCLUSION: Button batteries >20mm in diameter warrant increased clinical scrutiny due to higher likelihood and severity of injury. Implementation of recent pediatric gastroenterology societal guidelines will likely lead to a substantial increase in the number of CT and MRI examinations.

Magnetic resonance imaging of primary pediatric liver tumors.

Although primary hepatic neoplasms are less common than other intra-abdominal tumors in children, these neoplasms are a significant source of morbidity and mortality in the pediatric population. MRI is increasingly relied upon in the diagnostic evaluation of these lesions, both before and after treatment, and familiarity with the MRI findings associated with these neoplasms is a must for pediatric radiologists. Advances in MRI technology, particularly the advent of hepatocyte-specific gadolinium-based MRI contrast agents, have allowed for accurate characterization of several types of hepatic neoplasms on the basis of imaging appearance. In this review, we provide an overview of the approach to imaging hepatic neoplasms in children using MRI, including a sample imaging protocol. We also discuss the relevant clinical features and MRI findings of the most clinically relevant entities, including their appearance on post-contrast imaging using hepatocyte-specific gadolinium-based MRI contrast agents.

Simultaneous whole body (18)F-fluorodeoxyglucose positron emission tomography magnetic resonance imaging for evaluation of pediatric cancer: Preliminary experience and comparison with (18)F-fluorodeoxyglucose positron emission tomography computed tomography.

AIM: To describe our preliminary experience with simultaneous whole body (18)F-fluorodeoxyglucose ((18)F-FDG) positron emission tomography and magnetic resonance imaging (PET-MRI) in the evaluation of pediatric oncology patients. METHODS: This prospective, observational, single-center study was Health Insurance Portability and Accountability Act-compliant, and institutional review board approved. To be eligible, a patient was required to: (1) have a known or suspected cancer diagnosis; (2) be under the care of a pediatric hematologist/oncologist; and (3) be scheduled for clinically indicated (18)F-FDG positron emission tomography-computed tomography (PET-CT) examination at our institution. Patients underwent PET-CT followed by PET-MRI on the same day. PET-CT examinations were performed using standard department protocols. PET-MRI studies were acquired with an integrated 3 Tesla PET-MRI scanner using whole body T1 Dixon, T2 HASTE, EPI diffusion-weighted imaging (DWI) and STIR sequences. No additional radiotracer was given for the PET-MRI examination. Both PET-CT and PET-MRI examinations were reviewed by consensus by two study personnel. Test performance characteristics of PET-MRI, for the detection of malignant lesions, including FDG maximum standardized uptake value (SUVmax) and minimum apparent diffusion coefficient (ADCmin), were calculated on a per lesion basis using PET-CT as a reference standard. RESULTS: A total of 10 whole body PET-MRI exams were performed in 7 pediatric oncology patients. The mean patient age was 16.1 years (range 12-19 years) including 6 males and 1 female. A total of 20 malignant and 21 benign lesions were identified on PET-CT. PET-MRI SUVmax had excellent correlation with PET-CT SUVmax for both benign and malignant lesions (R = 0.93). PET-MRI SUVmax > 2.5 had 100% accuracy for discriminating benign from malignant lesions using PET-CT reference. Whole body DWI was also evaluated: the mean ADCmin of malignant lesions (780.2 + 326.6) was significantly lower than that of benign lesions (1246.2 + 417.3; P = 0.0003; Student's t test). A range of ADCmin thresholds for malignancy were evaluated, from 0.5-1.5 × 10(-3) mm(2)/s. The 1.0 × 10(-3) ADCmin threshold performed best compared with PET-CT reference (68.3% accuracy). However, the accuracy of PET-MRI SUVmax was significantly better than ADCmin for detecting malignant lesions compared with PET-CT reference (P < 0.0001; two-tailed McNemar's test). CONCLUSION: These results suggest a clinical role for simultaneous whole body PET-MRI in evaluating pediatric cancer patients.

Role of percutaneous abscess drainage in the management of young patients with Crohn disease.

BACKGROUND: Intra-abdominal abscess is a common complication of Crohn disease in children. Prior studies, primarily in adults, have shown that percutaneous abscess drainage is a safe and effective treatment for this condition; however, the data regarding this procedure and indications in pediatric patients is limited. OBJECTIVE: Our aim was to determine the success rate of percutaneous abscess drainage for abscesses related to Crohn disease in pediatric patients with a focus on treatment endpoints that are relevant in the era of biological medical therapy. MATERIALS AND METHODS: We retrospectively reviewed 25 cases of patients ages ≤20 years with Crohn disease who underwent percutaneous abscess drainage. Technical success was defined as catheter placement within the abscess with reduction in abscess size on post-treatment imaging. Clinical success was defined as (1) no surgery within 1 year of drainage or (2) surgical resection following drainage with no residual abscess at surgery or on preoperative imaging. Multiple clinical parameters were analyzed for association with treatment success or failure. RESULTS: All cases were classified as technical successes. Nineteen cases were classified as clinical successes (76%), including 7 patients (28%) who required no surgery within 1 year of percutaneous drainage and 12 patients (48%) who had elective bowel resection within 1 year. There was a statistically significant association between resumption of immunosuppressive therapy within 8 weeks of drainage and both clinical success (P < 0.01) and avoidance of surgery after 1 year (P < 0.01). CONCLUSION: Percutaneous abscess drainage is an effective treatment for Crohn disease-related abscesses in pediatric patients. Early resumption of immunosuppressive therapy is statistically associated with both clinical success and avoidance of bowel resection, suggesting a role for percutaneous drainage in facilitating prompt initiation of medical therapy and preventing surgical bowel resection.

Initial Clinical Experience With Extremity Cone-Beam CT of the Foot and Ankle in Pediatric Patients.

OBJECTIVE: Extremity cone-beam CT (CBCT) scanners have become available for clinical use in the United States. The purpose of this study was to review an initial clinical experience with CBCT of the foot and ankle in pediatric patients. MATERIALS AND METHODS: A retrospective review was conducted of all foot or ankle CBCT examinations performed on patients 18 years old and younger at one institution from August 1, 2013, through February 28, 2015. A t test was used to compare mean effective dose for CBCT with that for MDCT foot or ankle examinations of age-matched control subjects. To assess changes in utilization, a t test also was used to compare the mean numbers of foot or ankle CT examinations per month before and after installation of the CBCT scanner at the institution. RESULTS: Thirty-four CBCT examinations were performed. The mean effective dose was 0.013 ± 0.003 mSv compared with 0.023 ± 0.020 mSv for MDCT of age-matched control subjects (p < 0.005). The mean numbers of foot or ankle CT examinations per month were 3.4 in the 18 months before and 3.8 in the 18 months after installation of the CBCT scanner (p = 0.28). The mean number of foot or ankle MDCT examinations per month decreased significantly (3.4 vs 1.9, p = 0.03) over the same period. In 56% of patients, CBCT revealed important findings that were not visible on contemporaneous radiographs. In 68% of patients, the CBCT findings affected clinical management. CONCLUSION: CBCT of the foot or ankle of pediatric patients is a viable lower-dose alternative to MDCT that provides important information that may affect clinical management.

Review of Ingested and Aspirated Foreign Bodies in Children and Their Clinical Significance for Radiologists.

Ingested and aspirated foreign bodies are a common occurrence in children and are important causes of morbidity and mortality in the pediatric population. Imaging plays an important role in the diagnosis of ingested and aspirated foreign bodies in children and can be crucial to guiding the clinical management of these patients. Prompt identification and localization of ingested foreign bodies is essential to determining the appropriate treatment, as several types of commonly ingested foreign bodies require urgent removal and others can be managed conservatively. In particular, disk batteries impacted in the esophagus carry a high risk of esophageal injury or perforation; multiple ingested magnets can become attracted to each other across bowel walls and cause bowel perforation and fistula formation; and sharp objects commonly cause complications as they pass through the gastrointestinal tract. Accordingly, these ingested foreign bodies warrant aggressive clinical management and therefore radiologists must be familiar with their imaging appearances and clinical implications. Prompt recognition of secondary radiographic signs of foreign-body aspiration is also crucial, as clinical symptoms can sometimes be nonspecific and most aspirated foreign bodies are radiolucent. Overall, radiography is the most important modality in the evaluation of ingested or aspirated foreign bodies; however, fluoroscopy and computed tomography play an ancillary role in complicated cases. It is essential that every radiologist who interprets imaging examinations of children be aware of the imaging appearances of commonly ingested and aspirated foreign bodies and their clinical significance.

Role of MRI in the diagnosis and treatment of osteomyelitis in pediatric patients.

Osteomyelitis is a significant cause of morbidity in children throughout the world. Multiple imaging modalities can be used to evaluate for suspected osteomyelitis, however magnetic resonance imaging (MRI) has distinct advantages over other modalities given its ability to detect early changes related to osteomyelitis, evaluate the true extent of disease, depict extraosseous spread of infection, and help guide surgical management. MRI has assumed a greater role in the evaluation of osteomyelitis with the increase in musculoskeletal infections caused by methicillin-resistant Staphylococcus aureus which have unique imaging features that are well-demonstrated with MRI. This review focuses primarily on the use of MRI in the evaluation of osteomyelitis in children and will include a discussion of the clinically important and characteristic findings on MRI of acute bacterial osteomyelitis and related conditions.