Unusual Thymic Hyperplasia Mimicking Lipomatous Tumor in an Eight-Year-Old Boy with Concomitant Pericardial Lipomatosis and Right Facial Hemihypertrophy

We report a case of thymic hyperplasia accompanied by pericardial lipomatosis and right facial hemihypertrophy in an 8-year-old boy. On imaging studies, the hyperplastic thymus had prominent curvilinear and nodular fatty areas simulating a fat-containing anterior mediastinal mass, which is an unusual finding in children. To our knowledge, this is the first report on a child with a combination of thymic hyperplasia, pericardial lipomatosis, and right facial hemihypertrophy. The radiologic findings are presented with a brief discussion.

Balloon Dilatation for Corrosive Esophageal Strictures in Children: Radiologic and Clinical Outcomes

OBJECTIVE: We retrospectively evaluated the effectiveness of the esophageal balloon dilatation (EBD) in children with a corrosive esophageal stricture. MATERIALS AND METHODS: The study subjects included 14 patients (M:F = 8:6, age range: 17-85 months) who underwent an EBD due to a corrosive esophageal stricture. The causative agents for the condition were glacial acetic acid (n = 9) and lye (n = 5). RESULTS: A total of 52 EBD sessions were performed in 14 patients (range 1-8 sessions). During the mean 15-month follow-up period (range 1-79 months), 12 patients (86%) underwent additional EBD due to recurrent esophageal stricture. Dysphagia improved after each EBD session and oral feeding was possible between EBD sessions. Long-term success (defined as dysphagia relief for at least 12 months after the last EBD) was achieved in two patients (14%). Temporary success of EBD (defined as dysphagia relief for at least one month after the EBD session) was achieved in 17 out of 52 sessions (33%). A submucosal tear of the esophagus was observed in two (4%) sessions of EBD. CONCLUSION: Only a limited number of children with corrosive esophageal strictures were considered cured by EBD. However, the outcome of repeated EBD was sufficient to allow the children to eat per os prior to surgical management.

Clinical Application of Liver MR Imaging in Wilson's Disease

OBJECTIVE: To determine whether there is a correlation between liver MR findings and the clinical manifestations and severity of liver dysfunction in patients with Wilson's disease. MATERIALS AND METHODS: Two radiologists retrospectively evaluated MR images of the liver in 50 patients with Wilson's disease. The Institutional Review Board approved this retrospective study and informed consent was waived. MR images were evaluated with a focus on hepatic contour abnormalities and the presence of intrahepatic nodules. By using Fisher's exact test, MR findings were compared with clinical presentations (neurological and non-neurological) and hepatic dysfunction, which was categorized by the Child-Pugh classification system (A, B and C). Follow-up MR images were available for 17 patients. RESULTS: Contour abnormalities of the liver and intrahepatic nodules were observed in 31 patients (62%) and 25 patients (50%), respectively. Each MR finding showed a statistically significant difference (p < 0.05) among the three groups of Child-Pugh classifications (A, n = 36; B, n = 5; C, n = 9), except for splenomegaly (p = 0.243). The mean age of the patients with positive MR findings was higher than that of patients with negative MR findings. For patients with Child-Pugh class A (n = 36) with neurological presentation, intrahepatic nodules, surface nodularity, and gallbladder fossa widening were more common. Intrahepatic nodules were improved (n = 8, 47%), stationary (n = 5, 29%), or aggravated (n = 4, 24%) on follow-up MR images. CONCLUSION: MR imaging demonstrates the contour abnormalities and parenchymal nodules of the liver in more than half of the patients with Wilson's disease, which correlates with the severity of hepatic dysfunction and clinical manifestations.

Imperforate Anus: Determination of Type Using Transperineal Ultrasonography

OBJECTIVE: This study was designed to assess the usefulness of transperineal ultrasonography (US) for the determination of imperforate anus (IA) type. MATERIALS AND METHODS:From January 2000 to December 2004, 46 of 193 patients with an IA underwent transperineal US prior to corrective surgery. Sonographic findings were reviewed to identify the presence of internal fistulas and to determine "distal rectal pouch to perineum (P-P)" distances. IA types were determined based on the sonographic findings, and the diagnostic accuracy of transperineal US was evaluated based on surgical findings. RESULTS: Of the 46 patients, 17 patients were surgically confirmed as having a high-type IA, three patients were confirmed as having an intermediate-type IA and 26 patients were confirmed as having a low-type IA. The IA type was correctly diagnosed by the use of transperineal US in 39 of the 46 patients (85%). In 14 of the 17 patients with a high-type IA, internal fistulas were correctly identified. All cases with a P-P distance > 16 mm were high-type IAs and all cases with a P-P distance < 5 mm were low-type IAs. CONCLUSION: Transperineal US is a good diagnostic modality for the identification of internal fistulas in cases of high-type IA and for defining the IA level.

Power Doppler Imaging in Acute Renal Vein Occlusion and Recanalization: a Canine Model

OBJECTIVE: To evaluate the dynamic changes of the power Doppler (PD) in acute renal vein occlusion and recanalization in a canine model. MATERIALS AND METHODS: We performed a PD of the kidney during graded renal vein occlusion and recanalization induced by balloon inflation and deflation in nine dogs. The PD images were transferred to a personal computer, and the PD signals were quantified. RESULTS: We observed the temporal change of the PD signal during renal vein occlusion and recanalization, with a decrease in the PD signal during occlusion and an increase during recanalization. The mean PD signal decreased gradually as the renal vein was occluded, and conversely increased gradually with sequential relief of occlusion. The sequential change of the mean value of the PD signal was statistically significant. CONCLUSION: The PD can detect a change in renal blood flow during acute renal vein occlusion and recanalization in a canine model. The PD may be used as a helpful tool for the early detection of acute renal vein thrombosis and the monitoring of renal perfusion.

Congenital Absence of the Portal Vein Presenting as Pulmonary Hypertension

Congenital absence of the portal vein (CAPV) is a rare malformation in which intestinal and splenic venous flow bypasses the liver and drains directly into the systemic circulation via a congenital portosystemic shunt. We describe two cases of CAPV presenting as pulmonary hypertension that were initially suspected as primary pulmonary hypertension. However, subsequent ultrasonography and CT detected the absence of a portal vein and the presence of a portosystemic shunt. Pulmonary hypertension is a recognized complication of liver disease and portal hypertension. However, these two cases illustrate that CAPV may result in pulmonary hypertension without liver disease or portal hypertension.

Radiological Spectrum of Hepatic Mesenchymal Hamartoma in Children

OBJECTIVE: A hepatic mesenchymal hamartoma is an uncommon benign tumor in children and little is known about the spectrum of its radiological features. The purpose of this study is to describe the spectrum of radiological features of a hepatic mesenchymal hamartoma in children. MATERIALS AND METHODS: Thirteen children with a pathologically confirmed hepatic mesenchymal hamartoma (M:F = 7:6; mean age, 3 years 2 months) were included in our study. Ultrasonography (US) was performed in nine patients including color and power Doppler US (n = 7). CT scans were performed in all patients. We evaluated the imaging findings of the hepatic mesenchymal hamartomas and the corresponding pathological features. RESULTS: Each patient had a single tumor (mean diameter: 13 cm [1.8-20 cm]). On CT and/or US, four patients (31%) had a "multiseptated cystic tumor", five patients (38%) had a " mixed solid and cystic tumor", and four patients (31%) had a "solid tumor." The septa of the cystic portion were thin in the multiseptated cystic tumors and irregularly thick in the mixed solid and cystic tumors as seen on US. On a post-contrast CT scan, solid portions or thick septa of the tumors showed heterogeneous enhancement. The amount of hepatocytes was significantly different among the three tumor groups according to the imaging spectrum (p = 0.042). CONCLUSION: A hepatic mesenchymal hamartoma in children can show a wide spectrum of radiological features, from a multiseptated cystic tumor to a mixed solid and cystic tumor, and even a solid tumor.

MR findings in Acute Disseminated Encephalomyelitis in Children

PURPOSE: We reviewed the distribution of lesion and the characteristics of the MR findings of acute disseminated encephalomyelitis (ADEM) in children. We evaluated the differences in the imaging findings and the clinical outcomes between the patients with deep gray matter involvement and the patients without deep gray matter involvement. MATERIALS AND METHODS: We retrospectively reviewed the 62 MR examinations of 21 patients who were discharged with the clinical diagnosis of ADEM. The patients were aged from 13 months to 12 years old (mean age: 4.5 years). Follow-up MR examinations were done one to 5 times (mean: 3 times) for 2 weeks to 4 years (mean: 3 months) after the initial examination. We compared the signal intensity on T2WI, the enhancement and residue on the MR images and the clinical outcomes between the patients with deep gray matter involvement and the patients without deep gray matter involvement. RESULTS: A total of 21 patients had white matter abnormalities on their initial MR. Fifteen patients (71%) had foci of increased signal intensity on T2WI in the deep gray matter: thalamus (n=15), globus pallidus (n=14) and putamen (n=10). On the follow-up images, all patients showed decreased signal intensity and enhancement of their lesion. We could not find the significant differences in signal intensity, enhancement and residue on the MRIs and also the clinical outcomes between the patients with deep gray matter involvement and the patients without deep gray matter involvement (<.05). CONCLUSION: There were no significant differences in the characteristics of the imaging and the clinical outcomes between the ADEM patients with deep gray matter involvement and those ADEM patients without deep gray matter involvement.

Differentiation of Hyperplastic from Metastatic Lymph Nodes Using a Lymph Node Specific MR Contrast Agent Gadofluorine M

PURPOSE: We wanted to evaluate the value of a lymph node specific MR contrast agent, Gadofluorine M, for the differentiation of hyperplastic and metastatic lymph nodes. MATERIALS AND METHODS: This study included thirty-one rabbits. In ten rabbits, an injection of egg yolk or feces of rat into the calf muscles induced hyperplasia of the lymph node. In sixteen rabbits, metastasis of the lymph node was induced by implantation of VX2 tumor. Five rabbits were normal control models. We acquired the T1-, T2-weighted and SPGR coronal imaging before enhancement with 1.5 T MR. After injection of Gadofluorine M (5 micromol/mL, total amount: 4 mL) interstitially into the interdigital skin fold of the hind limb, we acquired the SPGR coronal imaging at 15, 30, 60 and 90 minutes. We calculated the signal-to-noise ratios on the sequential images, and we recorded the number, size and location of the popliteal and iliac lymph nodes. Three readers assessed the state of the lymph nodes according to the pattern of enhancement: they were deemed hyperplastic nodes when totally enhanced and as metastatic nodes when there was no or partial enhancement. We also compared the imaging patterns with the histopathological results. RESULTS: Among the 26 hyperplasia- or metastasis-induced rabbits, two rabbits were excluded because of failure to be enhanced. Histopathologic evaluation of the 24 rabbits detected one hundred seventeen lymph nodes: forty-six lymph nodes in nine hyperplasia-induced rabbits and seventy-one (metastasis in twenty-eight) lymph nodes in fifteen metastasis-induced rabbits. Out of one hundred two lymph nodes that were larger than 5 mm in size, MR enabled us to detect one hundred one lymph nodes (99.1%). The means of sensitivity, specificity, and the positive and negative predictive values for the diagnosis of lymph node metastasis by three readers were 97.6% (82/84), 98.2% (215/219), 95.3% (82/86), and 99.1% (215/217), respectively (p < 0.05). CONCLUSION: Interstitial MR lymphography using Gadofluorine M showed excellent results in differentiating hyperplastic from metastatic lymph nodes.

Metanephric Adenoma of the Kidney in an Infant: A Case Report

Metanephric adenoma is a rare tumor of the kidney that has been reported mostly in adults. Despite its rarity, metanephric adenoma should be included in any differential diagnosis of solid renal masses in children, especially because of its benign nature and benign clinical course allowing for nephron sparing surgery. We report a case of metanephric adenoma, presented as a solid renal mass in a 14-month-old boy, and discuss the histologic basis of the imaging features of this entity.

Standard Bone-Age of Infant and Children in Korea

To evaluate the developmental status of children and adolescents, bone-age chart based on the radiograph of hand and wrist has been used in many countries. The bone-age reflects not only the functional status of various hormones but also the influence of chronic disease, and it has been used more widely than other indices such as height-weight-age table. As the standard bone-age chart has not been established in Korea, the foreign bone-agechart has been used radiographs in the clinics. To make Korean standard bone-age chart, we took the radiographs ofthe left hand in about 5400 children covering the whole country, and 3407 radiographs of 1830 boys and 1577 girls ranging from two months to 16 years of age were selected and analyzed for bone maturity scores by TW2-20 method. The range of age were divided into 27 groups, and the radiographs of 50th percentile score were chosen as the standard bone-ages for the median age of each group. The youngest and oldest chronological age which had the same TW2-20 score of the standard bone-age were decided as the range of variation from the median age. we hope that Korean standard bone-age chart be used as the radiological criteria in the evaluation of the developmenta status in Korean children and adolescents.

Radiologic findings of pulmonary angiodysplasia

Pulmonary angiodysplasia indicates all forms of abnormal intrapulmonary arteriovenous comunication, usuallycalled pulmonary arteriovenous fistula. Most frequent form of pulmonary angiodysplasia is single or multiplediscrete nodular lesion, and diffuse telangiectatic type consists another variety. More than 50% of pulmonaryangiodysplasias are associated with hereditary hemorrhagic telangiectasia. And rearely chronic liver disease iscomplicated by pulmonary arteriovenous fistula which is called hepatogenic pulmonary angiodysplasia. Weexperienced 6 cases of pulmonary angiodysplasia confirmed by cardiac catheterization and angiography from 1977 to1983. 5 cases were children below 11 years of age exhibiting cyanosis except one who has pulmonary angiodysplasiasupplied by systemic arteries. 3 were hereditary hemorrhagic telangiectasia and one was hepatogenic pulmonaryangiodysplasia. Discrete nodular pulmonary lesion was present in 3 cases while remaining 3 cases were diffusetelangiectatic type. The clinical and radiological findings of pulmonary angiocysplasia is described with a briefreview of literature.

Chest PA findings of leukemia in children

Leukemia is the commonest malignancy in childhood, accounting for about one-third of all malignancies in thosebelow the age of 15 years. Authors analysed the chest PA findings of 177 cases of leukemia in childhood below theage of 15 years, diagnosed at Seoul National University Hospital in recent 5 years since 1978. The summaries ofthe analysis are as follows; 1. Among 177 cases, 121 cases were male and 56 cases were female. The malepredominant than the female with the ratio of 2.2:1. In 177 cases, 77% of the patients were under the 10 years ofage. 2. The incidence of subtype of leukemia was as follows; The acute form was 158 cases (89%), acute lymphocyticleukemia, 55%, acut myelocytic group, 31.6%, chronic myelocytic type, 10%. And acute lymphocytic leukemia was61.4% of acute form. 3. The incidence of abnormality in chest PA was 32.2%(57 cases) . Among these 57 cases,abnormality in lung field was 35 cases (19.8% of total patients) hilar and mediastinal lymph nodes enlargement was19 cases(10.7%). Pleural effusion was 13 cases (7.3%) and cardiac shadow enlargement in chest PA was 3 cases.

Radiological analysis of pulmonlary sequestration

Pulmonary sequestration , defined as loss of connection of the lung tissue with bronchial tree and withpulmonary artery receiving its artery supply from the systemic artery, is very rare cngenital pulmonary disease.It presents as two types, intralobular or extralobular differentiated by its location. 6 cases of pulmonarysequestrations hve been diagnosed in Seoul National University Hospital. 5 cases were confirmed pathologicallyafter lobectomy. 1 case was diagnosed with cardiac cineangiogram only. The results are as follows; 1. 4 cases hadclinical histories of pulmonary sepsis. 2 cases had cardiac problems without suspicion of the lung problem. 2. 4cases are male and 2 cases are female. 3. Ages of the patients are distributed from 2 months of age to 15 years ofage. 4. 4 cases are angiographically confirmed preoperatively. 2 cases had no suspicion of pulmonary sequestrationpreoperatively. 5. 3 cases are associated wtih cardiovascular anomalies such as right sided aortic arch, pulmonarystenosis, complicated heart disease. 6. 5 cases- operatively proven-have intralobar types with cystic change. 7.CT was performed in one case who shows left lower lobe area mass with air bronchogram.

Radiological findings of the estragonadal endodermal sinus tumors in children

Endodernal sinus tumors(EST) are generally recognized as a germ cell tumors with extraembryonicdifferentiation that resemble the endodermal sinus of the rat placenta. Like other germ cell tumors the primaryEST may either occur in the gonads or in specific extragonadal sites. CT is the most accurate study in delineatingthe extent of primary and metastatic lesions particularly in the pelvis. Recently authors experienced six cases ofthe pathologically proven extragonadal endodermal sinus tumors in children and retrospectively analyzed theradiological findings including the CT. The results were as follows: 1 Of the 6 cases of extragonadal EST, theprimary lesion presented in the sacrococcygeal region in 5 patients and liver in one patient. 2. There were 4females and 2 males. Of the sacrococcygeal lesions 3 were females and 2 were males. 3. The age of presentationranged from 9 months to 3 years of age(mean age=21 months) 4. Conventional radiographic study of thesacrococcygeal lesion showed presacral, retrorectal soft tissue mass without calcification which extended into thebuttock. CT revealed well circumscribed enhancing soft tissue mass with irregular central low density areas. 5.Primay EST of the liver revealed ill-defined inhomogeneous mixed echogenic mass( ultrasound) and ill-defined lowdensity mass(CT). Angiography showed hypervascular mass with areas of necrosis and no evidence portal veininvasion. A-V shunting was not present. 6. Reginal lymph node metastasis was present at the time of diagnosis in 2cases of sacrococcygeal EST. 7. Local recurrence of tumor was noted in 2 patients with sacrococcygeal lesion aftersurgery and chemotherapy.

Radiologic analysis of total colonic aganglionosis

Radiologic findings of Total colonic Aganglionosis(T.C.A.) were analized in 15 patients with the results asfollows; 1. Male to female ratio was 8:7. 2. There were six cases of small calibered colon, seven cases of normalcolon and two cases of megacolon. 3. Free reflux of barium into the small bowel was observed in seven cases out ofeight in which retrograde filling was tried. 3. Delayed films (24 hrs or more) were available in eight cases andmost of the barium remaned in bowel in six cases. 5. There were abnormal colonic contractions in three cases,decreased redundancy in five and five cases of irregular, hypertrophic mucosal wall suggesting enterocolitis. 6.Part of ileum were also aganglionic in five cases. There seems to be no pathognomonic barium enema findings inT.C.A. But combination of these findings may suggest the possibility of T.C.A. T.C.A. should be considered indifferential diagnosis of bowel obstruction in infants. Barium enema should be complete and delayed films alwaysbe obtained.

The currarino triad of anorectal, sacral, and presacral anomalies

The Currarino triad is a unique complex of congenital anomalies including anorectal malformation, scral bonyabnormality, and presacral mass. The usual symptomatology is constipation due to anorectal stenosis. Threepatients with this triad confirmed by surgical operation during recent two yeas in Seoul National Universitychildren's Hospital were presented with a brief review of clinical features, unique radiologic appearance andpostulated pathophysiology. The presacral mass was a mature teratoma in the first patient, alipomyelomeningocele-epidermoid inclusion cyst in the second patient, and myelomeningocele in the third patient. Acorrect diagnosis of the Currarino triad by radiologists is important, and may help the phsicians to investigatedetailed family history and associated anomalies and to establish adequate surgical plans.

Differentiation between Tuberculous and Pyogenic Spondylitis: MR Imaging Characteristics of Paraspinal Mass

PURPOSE: To determine the MR imaging findings for the differentiation of tuberculous spondylitis(TS) and pyogenic spondylitis(PS) with emphasis on the shape and MR signal characteristics of paraspinal mass. MATERIALS AND METHODS: We obtained spin-echo T1- and T2-weighted MR images of 63 surgically proved cases of TS and 15 casesof PS. Gadopentetate dimeglumine(Gd)-enhanced T1-weighted MR images in 37 cases of TS and in all 15 cases of PS were also obtained. Paraspinal mass formation, the size, shape and Gd-enhancing pattern of this mass and penetration of paraspinal ligaments by inflammatory tissue were analyzed. RESULTS: Paraspinal mass was found inboth TS(63/63) and PS(9/15). The mean longitudinal dimension of this mass was 4.3 vertebral body heights in TS and1.8 in PS. The margin of the mass was smooth in TS due to subligamentous spread of inflammation, while PS showedan irregular margin and invaded the para-aortic or para-caval space(9/15) due to penetration of inflammatory tissue through the paraspinal ligament. In the lumbar spine, however, TS showed focal penetration of the paraspinal ligament and formed psoas abscesses. After Gd enhancement, TS showed irregular thick or uniformly thinrim enhancement(35/37), suggesting caseation necrosis and cold abscess, while PS showed diffuse enhancement, suggesting abundant granulation tissue. CONCLUSION: MR imaging findings helpful for the differentiation of TS andPS were size, shape and enhancing pattern of paraspinal mass and penetration of paraspinal ligament by inflammatory tissue.

A microangiographic study on renal artery embolization

Renal artery embolization was induced experimentally in rabbits and microvascular changs were studiedangiographically, microangiographically and histopathologically. The results were as follows; 1. The mainmicroangiographic findings of renal artery embolization were arterial occlusion and collateral vessels arecharacterized by spiralling, dilatation, irregular lumen with abrupt caliber change, disoriented course andincreased number. 2. Collateral vessel formation was demonstrated in all cases of renal artery embolization bymicroangiography. 3. Recanalization of embolized vessels was better visualized by renal angiography thanmicorangiography. It was considered that microangiography is a valuable method for the observation ofmicrovascular changes in renal artery embolization and other renal diseases.

An radiology study of pediatric pulmonary cryptococcosis

Cryptococcosis is a cosmopolitan mycotic disease caused by a yeast like fungus, Cryptococcus neoformans. Resiratory tract, as portal of entry, is the initial focus of infection. Initial pulmonary lesion may heal with orwithout dissemination of the disease. Authors reviewed 8 cases of confirmed cryptococcosis during Jan. 1973 toJune 1981 at Seoul National University Hsopital. The resuls are as follows; Majority of the cases are below 5years old. The most common symptoms are fever, abdominal pain and distension, and respiratory symptoms in only 2cases. The involved organs are liver, lymph node, spleen, meninges, and skin in the order of frequency. Chest P-Aroentgenograms show both hilar enlargement with perihilar and basilar, linear and small nodular infiltrations. Miliary nodular lesions and mediastinal lymphadenopathy were also noted.