Ah Young Jung

Angiomyxolipoma (vascular myxolipoma) of the knee in a 9-year-old boy.

Angiomyxolipoma (vascular myxolipoma) is a very rare variant of lipoma. This tumor is characterized by mature adipose tissue mixed with myxoid stroma and vascular vessels. To date, nine cases have been reported, all of them occurring in adults. Herein, we report a unique case of a 9-year-old boy presenting with a solitary painful mass on the right medial thigh and illustrate the imaging characteristics of this rare tumor.

Multidetector CT Findings of Bowel Transection in Blunt Abdominal Trauma

Objective Though a number of CT findings of bowel and mesenteric injuries in blunt abdominal trauma are described in literature, no studies on the specific CT signs of a transected bowel have been published. In the present study we describe the incidence and new CT signs of bowel transection in blunt abdominal trauma. Materials and Methods We investigated the incidence of bowel transection in 513 patients admitted for blunt abdominal trauma who underwent multidetector CT (MDCT). The MDCT findings of 8 patients with a surgically proven complete bowel transection were assessed retrospectively. We report novel CT signs that are unique for transection, such as complete cutoff sign (transection of bowel loop), Janus sign (abnormal dual bowel wall enhancement, both increased and decreased), and fecal spillage. Results The incidence of bowel transection in blunt abdominal trauma was 1.56%. In eight cases of bowel transection, percentage of CT signs unique for bowel transection were as follows: complete cutoff in 8 (100%), Janus sign in 6 (100%, excluding duodenal injury), and fecal spillage in 2 (25%). The combination of complete cutoff and Janus sign were highly specific findings in patients with bowel transection. Conclusion Complete cut off and Janus sign are the unique CT findings to help detect bowel transection in blunt abdominal trauma and recognition of these findings enables an accurate and prompt diagnosis for emergency laparotomy leading to reduced mortality and morbidity.

Liver Stiffness Measured by Shear-wave Elastography for Evaluating intra-hepatic Portal Hypertension in Children.

Objectives: The aim of the study was to correlate liver stiffness (LS) and hepatic venous-pressure gradient (HVPG) and to evaluate the diagnostic performance of shear-wave elastography (SWE) for predicting clinically significant portal hypertension in children with suspected liver diseases, in consideration of the reliability criteria. Methods: We identified 33 SWEs from 32 children who underwent HVPG measurement within 2 weeks between June 2012 and October 2015. The correlation between LS and HVPG was assessed. The diagnostic performance for predicting clinically significant portal hypertension (HVPG ≥ 10 mmHg) was assessed using the receiver-operating characteristic curve. Reliable measurement was evaluated based on the coefficient of variation (CV). Results: LS was significantly correlated with HVPG (r = 0.742, P < 0.001). The area under the receiver-operating characteristic curve for predicting clinically significant portal hypertension was 0.914, and the best cutoff value of 18.4 kPa showed sensitivity of 87.5% and specificity of 84.0%. LS measurements having CV ⩽ 0.2 were significantly correlated with HVPG (r = 0.774, P < .001), whereas those having CV > 0.2 did not show a significant correlation with HVPG (r = 0.598, P = 0.089). Conclusions: SWE had excellent diagnostic performance for predicting clinically significant portal hypertension in children with suspected liver diseases. LS measurements having CV ⩽ 0.2 may possibly be used as a reliability criterion in SWE measurement.

Anomalous Double Right Coronary Arteries: Characteristic Multidetector-Row Computed Tomography Findings

Purpose: To evaluate the characteristic multidetector-row computed tomography (MDCT) findings of anomalous double right coronary arteries (RCAs), an extremely rare variant. Methods: During a 3-year period, 2569 patients with chest pain underwent MDCT coronary angiography. Five patients (0.2%) with anomalous double RCAs were found (mean age, 66 years; range, 43-81 years; 3 women). The location and number of orifice, anatomical distribution of the RCA and its branches, and presence of atherosclerosis were analyzed. Results: All the 5 cases of double RCAs originated from the right sinus of Valsalva and could be classified into 3 types according to the characteristics. One patient (type 1) had a double RCA arising from 2 separated orifices in the right sinus of Valsalva; another patient (type 2) had 2 separate RCAs originating from a common orifice in the sinus of Valsalva; the other 3 patients with double RCAs (type 3) had a common main RCA in the sinus of Valsalva with a proximal bifurcation, like the usual left coronary arterial system. Conclusions: Our data showed that although a double RCA is a rare anomaly, it is easily detected using MDCT and can be classified into 3 types.

Cranial Nerve Disorders in Children: MR Imaging Findings.

Cranial nerve disorders are uncommon disease conditions encountered in pediatric patients, and can be categorized as congenital, inflammatory, traumatic, or tumorous conditions that involve the cranial nerve itself or propagation of the disorder from adjacent organs. However, determination of the normal course, as well as abnormalities, of cranial nerves in pediatric patients is challenging because of the small caliber of the cranial nerve, as well as the small intracranial and skull base structures. With the help of recently developed magnetic resonance (MR) imaging techniques that provide higher spatial resolution and fast imaging techniques including three-dimensional MR images with or without the use of gadolinium contrast agent, radiologists can more easily diagnose disease conditions that involve the small cranial nerves, such as the oculomotor, abducens, facial, and hypoglossal nerves, as well as normal radiologic anatomy, even in very young children. If cranial nerve involvement is suspected, careful evaluation of the cranial nerves should include specific MR imaging protocols. Localization is an important consideration in cranial nerve imaging, and should cover entire pathways and target organs as much as possible. Therefore, radiologists should be familiar not only with the various diseases that cause cranial nerve dysfunction, and the entire course of each cranial nerve including the intra-axial nuclei and fibers, but also the technical considerations for optimal imaging of pediatric cranial nerves. In this article, we briefly review normal cranial nerve anatomy and imaging findings of various pediatric cranial nerve dysfunctions, as well as the technical considerations of pediatric cranial nerve imaging. Online supplemental material is available for this article. (©)RSNA, 2016.

Rhabdomyosarcoma in Children and Adolescents: Patterns and Risk Factors of Distant Metastasis

OBJECTIVE The objective of this study is to evaluate patterns of distant metastasis and identified factors that may increase the risk of distant metastasis in pediatric patients with rhabdomyosarcoma. MATERIALS AND METHODS This retrospective study included 69 patients (age, ≤ 20 years) who had rhabdomyosarcoma diagnosed between January 2000 and February 2016. Various imaging features, including distant metastasis, were evaluated on initial and follow-up imaging studies. Differences in the distribution of distant metastasis on the basis of the primary location were analyzed. Logistic regression analysis was performed to identify factors associated with distant metastasis. RESULTS Twenty-six of the 69 patients (37.7%) had distant metastasis. Nineteen of the 26 patients had distant metastasis noted at initial presentation, and 15 of the 26 patients had new metastasis noted during follow-up. The most common site of metastasis was bone (n = 14), followed by lung (n = 12) and distant lymph nodes (n = 9). Lymph node metastasis more frequently developed in patients with primary rhabdomyosarcoma in an extremity than in patients with primary rhabdomyosarcoma that developed at other sites (p = 0.003). Of 15 patients who had metastasis during follow-up, nine (60%) did not appear to have simultaneous locoregional recurrence at the time of the discovery of distant metastasis. Older age at presentation and unfavorable sites of the primary tumor were significantly associated with distant metastasis in multivariate analysis. CONCLUSION Distant metastasis of rhabdomyosarcomas in pediatric patients showed different patterns according to the location of the primary tumor and even occurred without local recurrence.

Risk Estimation for Biliary Atresia in Patients with Neonatal Cholestasis: Development and Validation of a Risk Score

Purpose To develop and validate a scoring system based on clinical and imaging features to predict the risk for biliary atresia in patients with neonatal cholestasis. Materials and Methods Patients with neonatal cholestasis who underwent both ultrasonography (US) and hepatobiliary scintigraphy (n = 480) were retrospectively identified from two tertiary referral hospitals from January 2000 to February 2017. Patients from one hospital were classified as the derivation cohort (n = 371), and those from the other hospital were classified as the validation cohort (n = 109). Clinical and imaging features associated with biliary atresia were assessed. Histopathologic or intraoperative cholangiographic findings served as the reference standard for biliary atresia. A prediction model was developed by using logistic regression and was then transformed into a scoring system. The scoring system was internally and externally validated. Results Among the 371 patients in the derivation cohort, 97 (26.15%) had biliary atresia. A scoring system was constructed with the following variables: full-term birth, presence of the triangular cord sign at US, abnormal gallbladder morphology at US, and failure of radioisotope excretion to the small bowel at hepatobiliary scintigraphy. The maximum possible score with this system is 7 points. This system enabled differentiation of biliary atresia in the derivation cohort (C statistic, 0.981; 95% confidence interval [CI]: 0.970, 0.992) and the validation cohort (C statistic, 0.995; 95% CI: 0.987, 1.000). The risk score also showed good calibration in both the derivation and the validation cohorts (P = .328 and P = .281, respectively). Conclusion A simple scoring system combining clinical and imaging features can help accurately estimate the risk for biliary atresia in patients with neonatal cholestasis.

Imaging findings of angiomyxolipoma of the spermatic cord mimicking inguinal hernia

We report the case in a 72-year-old man who presented with a right inguinal mass and with a one month history that was initially interpreted as an inguinal hernia. Ultrasonography (US) and computed tomography (CT) demonstrated a right inguinal mass, including myxoid and fat component, extending from the right spermatic cord to the right inguinal subcutaneous layer. Mass excision was performed, and the diagnosis turned out to be angiomyxolipoma. Angiomyxolipoma is a rare tumor and the preoperative diagnosis of this disease is very difficult. However, angiomyxolipoma of the spermatic cord should be considered in the differential diagnosis in patients with an irreducible inguinal mass. Imaging diagnosis, such as US and CT may help to make a preoperative diagnosis.