Echo-planar imaging is a very fast magnetic resonance (MR) imaging technique capable of acquiring an entire MR image in only a fraction of a second. In single-shot echo-planar imaging, all the spatial-encoding data of an image can be obtained after a single radio-frequency excitation. Multishot echo-planar imaging results in high-quality images comparable to conventional MR images. However, echo-planar imaging offers major advantages over conventional MR imaging, including reduced imaging time, decreased motion artifact, and the ability to image rapid physiologic processes of the human body. The use of echo-planar imaging has already resulted in significant advances in clinical diagnosis and scientific investigation, such as in evaluation of stroke and functional imaging of the human brain, respectively. The clinical indications for echo-planar imaging are expanding rapidly, and it can now be applied to many parts of the body, including the brain, abdomen, and heart. Today, with the availability of echo-planar imaging-capable MR imagers at many sites, the general radiologist can benefit from echo-planar imaging and its clinical applications.

Radiation-induced bone changes and second malignancies, as well as benign tumors, following bone marrow transplantation are being reported with increasing frequency. An osteosarcoma of the fourth right rib and an osteochondroma of the left scapula developed in a long-term survivor of abdominal neuroblastoma treated with chemotherapy, local radiation, and bone marrow transplantation. All these treatment modalities are known to induce neoplasia.

A 70-year-old Afghan refugee who recently immigrated to the United States had a history of dyspnea on exertion for several months. Medical history included systemic hypertension, recent onset of congestive heart failure, and recent peripheral pitting edema of the lower extremities. A soft systolic heart murmur with a split S 2 was present at physical examination. An echocardiogram showed findings that prompted the request for a cardiac magnetic resonance (MR) imaging examination for further evaluation (Figs 1-3). IMAGING FINDINGSMR images demonstrated moderate right atrial enlargement, with a membrane separating the right atrium into an anterior and a posterior chamber (Figs 1, 2). Turbulent flow was seen across this membrane (Fig 2; Movie, radiology.rsnajnls.org/cgi /content/full/10.1148/radiol.2263001845/DC1) and indicated that it was extensively fenestrated and not completely obstructive. Gradient-echo cine images demonstrated a small secundum atrial septal defect (ASD) that was approximately 4 mm in diameter (Fig 3). A small left-to-right jet through the ASD was also seen on the cine images. The right ventricle was mildly enlarged. There was mild enlargement of bilateral pulmonary arteries. Mild left ventricular hypertrophy was present, which was likely related to the patient's known systemic hypertension. Findings of the examination of the remainder of the heart were within normal limits. DISCUSSIONWhile on the basis of the clinical findings the differential diagnosis considerations included entities such as constrictive pericarditis, tricuspid stenosis, or right atrial tumor, the imaging findings helped to narrow the possibilities to one diagnosis: cor triatriatum dexter. The term cor triatriatum, also known as "triatrial heart," usually refers to cor triatriatum sinister or "divided left atrium," which is a rare condition with estimated incidence of 0.1% of all congenital cardiac malformations (1). In cor triatriatum sinister, the left atrium is divided by a membrane into a posterior-superior chamber that receives the four pulmonary veins and an anterior-inferior chamber that connects to the left ventricle by means of the mitral valve. Although several theories have been proposed in the literature regarding the development of cor triatriatum sinister, the most widely accepted theory is that this anomaly results from a failure of incorporation of the common pulmonary vein into the left atrium (2,3).The case presented in this article is an example of cor triatriatum dexter in which a membrane divides the right atrium into two chambers. It is generally believed that cor triatriatum dexter results from persistence of the right valve of the sinus venosus (4 -6). During embryogenesis, the right horn of the sinus venosus gradually incorporates into the right atrium to form the smooth posterior portion of the right atrium, whereas the original embryologic right atrium forms the trabeculated anterior portion. The connection between the right horn of the sinus venosus and the embryologic right atrium is the sinoatri...

We describe four cases of inflammatory pseudotumor seen at our institution in the past 4 years. Four children were each found to have a large extraperitoneal mass on imaging studies, three of which were in the pelvis. Malignant sarcomatous tumors were suspected. Surgical biopsy of each mass, however, revealed inflammatory pseudotumor.

Background -The usefulness of spiral computed tomographic (CT) scans of the chest with three dimensional imaging (3D-CT) of intrathoracic structures in the diagnosis and management of paediatric intrathoracic airway obstruction was assessed. Methods -A retrospective review was made of five consecutive cases (age range six months to four years) admitted to the paediatric intensive care unit and paediatric radiology division of a tertiary care children's hospital with severe respiratory decompensation suspected ofbeing caused by intrathoracic large airway obstruction. Under adequate sedation, the patients underwent high speed spiral CT scanning of the thorax. Non-ionic contrast solution was injected in two patients to demonstrate the anatomical relationship between the airway and the intrathoracic large vessels. Using computer software, three-dimensional images of intrathoracic structures were then reconstructed by the radiologist. Results -In all five patients the imaging results were useful in directing the physician to the correct diagnosis and appropriate management. In one patient, who had undergone repair of tetralogy of Fallot with absent pulmonary valve, the 3D-CT image showed bilateral disruptions in the integrity of the tracheobronchial tree due to compression by a dilated pulmonary artery. This patient underwent pulmonary artery aneurysmorrhaphy and required continued home mechanical ventilation via tracheostomy. In three other patients with symptoms oflower airway obstruction the 3D-CT images showed significant stenosis in segments of the tracheobronchial tree in two of them, and subsequent bronchoscopy established a diagnosis of segmental bronchomalacia. These two patients required mechanical ventilation and distending pressure to relieve their bronchospasm. In another patient who had undergone surgical repair of intrathoracic tracheal stenosis three years prior to admission the 3D-CT scan ruled out restenosis as the reason for her acute respiratory decompensation.Conclusions -3D-CT scanning is a useful additional diagnostic tool for intrathoracic airway obstruction in paediatric patients.

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Papillary-cystic neoplasm of the pancreas is a rare, nonfunctioning low-grade malignant tumor seen in young patients, most often female. Ultrasound and CT show a circumscribed, solid nonhomogeneous mass with cystic areas, with peripheral but not central enhancement and occasional calcification. Prognosis after excision is usually excellent. We describe a case of the papillary-cystic neoplasm of the pancreas in a 13-year-old girl to illustrate the radiological findings.

Juvenile xanthogranuloma (JXG) is a disorder of histiocytes usually associated with cutaneous lesions. It may present a diagnostic dilemma in the absence of cutaneous lesions and when deeply located. Differentiation of JXG from other childhood histiocytosis syndromes, especially Langerhans' cell histiocytosis (LCH), is important. We describe an unusual case of deep JXG in a 27-month-old girl with multiple omental and peritoneal nodules presenting with ascites. Although a diagnosis of LCH was suspected clinically, the absence of Birbeck granules and S-100 protein and T6 antigen negativity, together with CD68 and factor XIIIa positivity, led us to a diagnosis of JXG. Physicians should be aware of the widening spectrum of manifestations of juvenile xanthogranuloma.