MRI is increasingly used because it is a noninvasive imaging modality that offers excellent anatomic detail, enabling the differentiation of ossified and unossified components of the hip. The radiologist should be aware of the increasing role of MRI and recognize the critical MRI findings of DDH.

We report the case of a 6-year-old girl presenting with acute appendicitis complicated by perforated appendix, followed by perihepatic abscess associated with ectopic appendicoliths. CT findings were initially suspicious for an intrahepatic abscess with internal calcifications. However, on sonography the abscess appeared to be in a perihepatic location. Perihepatic abscess associated with a dropped or retained appendicolith has been rarely reported. Awareness of the possibility of a perihepatic abscess as a complication of laparoscopic appendectomy and use of sonography should result in optimal management of this rare complication.

Background: There are currently no clear guidelines for the management and radiological monitoring of pediatric patients with epidural hematomas (EDH). We aim to compare clinical and radiographic characteristics of pediatric EDH patients managed with observation alone versus surgical evacuation and to describe results of repeat head imaging in both groups. Methods: We performed a retrospective observational study of pediatric patients diagnosed with traumatic EDH at a level II trauma center. Results: Forty-seven cases of EDH were analyzed. Sixty-two percent were managed by observation alone. Patients undergoing surgery were more likely to have an altered mental status (17 vs. 72%, p < 0.001), but there were no other significant clinical differences between the groups. The mean initial EDH thickness and volume were 8.0 mm and 8.6 ml in the observed group and 15.5 mm and 35 ml in the surgery group, respectively (p < 0.001 for both comparisons). Eighty-six percent of the observed and all surgery patients underwent repeat CT imaging. The initial repeat CT scan results led to surgery in 1 patient who was initially treated with observation. Conclusions: Most pediatric patients with EDH can be managed with observation. Mental status and radiographic findings should guide the need for surgical intervention. Multiple repeat CT scans have minimal utility in changing management.

To determine the optimal time window for MR imaging with quantitative ADC measurement in neonatal HIE after hypothermia treatment, a retrospective review was performed on consecutive hypothermia-treated term neonates with HIE, with an initial and follow-up MR imaging within the first two weeks of life. Three neuroradiologists categorized each set of MR imaging as normal, mild, moderate or severe HIE based on a consensus review of the serial imaging. The lowest ADC values from the white matter, corpus callosum, and basal ganglia/thalamus were measured. The ADC values between mild-moderate and severe HIE were compared using a Student's t-test over a range of different time windows. A total of 33 MR imaging examinations were performed on 16 neonates that included three normal, four mild, five moderate, and four severe HIE. The time window of 3-10 days showed a statistically significant decrease in ADC value in severe HIE compared to mild-moderate HIE in all three locations, respectively: white matter 0.5 ± 0.22 versus 0.83 ± 0.27 ( p value 0.01), corpus callosum 0.69 ± 0.19 versus 0.91 ± 0.17 ( p value 0.01), and basal ganglia/thalamus 0.63 ± 0.16 versus 0.98 ± 0.06 ( p value <0.01). The range of 3-10 days is the optimal time window for MR imaging with quantitative ADC after hypothermia treatment.

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