ENG 1001G-010: English Composition & Language

International audienc

Role of CT in the evaluation of children with foregut cyst

The presentation of a foregut cyst may vary from an asymptomatic mass discovered as an incidental finding in a chest radiograph, to signs or symptoms secondary to airway compression by the cyst. The radiographic evaluation of a child with a possible foregut cyst usually consists of a chest radiograph and barium esophagogram. Although this approach is often sufficient, in other instances delay of treatment occurs or unnecessary workups are performed due to the inadequacy of the approach. CT is useful for (a) depicting cryptic foregut cysts, (b) clarifying abnormal radiographs, (c) avoiding unnecessary workup of patients by establishing the precise location of the mass, and (d) defining the cystic nature of the mass and excluding other etiologies.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46685/1/247_2006_Article_BF02388234.pd

MR findings of endocardial fibroelastosis in children

BACKGROUND: Endocardial fibroelastosis (EFE) is characterized by a diffuse white fibrous tissue lining the endocardium. The diagnosis is difficult to establish because clinical symptoms and electrocardiographic findings are nonspecific. Surgical resection of EFE requires the establishment of the diagnosis and delineation of the extent of the fibrotic changes. OBJECTIVE: To describe the use of MRI in the assessment of EFE in children. MATERIALS AND METHODS: Three children after surgery for aortic stenosis who were suspected of having EFE were evaluated by echocardiography and MRI. The MR evaluation consisted of black-blood, triple IR, bright-blood, perfusion and myocardial delayed-enhancement sequences. EFE was confirmed at surgery in all patients. RESULTS: Echocardiograms demonstrated vigorous systolic function but substantial diastolic dysfunction of the left ventricle in all. Mild endocardial brightening of the anterior septum, anterior wall, or papillary muscles was present in two. No study was thought to be diagnostic of endocardial fibrosis. On MRI EFE manifested at the endocardial surface as a rim of hypointense signal in the perfusion sequences and as a rim of hyperintense signal in the myocardial delayed-enhancement sequences. The black-blood, triple IR, and bright-blood sequences were not diagnostic. CONCLUSION: The diagnosis of EFE is difficult to establish by echocardiography. MRI using perfusion and myocardial delayed enhancement can be useful in establishing the diagnosis

Transfusional Iron Overload in Sickle Cell Anemia

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72471/1/j.1749-6632.1989.tb24225.x.pd

Magnetic resonance imaging of mediastinal vessels

MRI complements echocardiography and cineangiography in the evaluation of the great vessels. Advantages of echocardiography are its low cost, ready availability, and portability. Similar to echocardiography, MRI is noninvasive and lacks ionizing radiation, but it also has the advantages of multiplanar imaging and large field of view. This article reviews the indications for MRI of the great vessels of the chest and the magnetic resonance (MR) appearance of some of the more common anomalies of the pulmonary arteries, aorta, and systemic and pulmonary veins. MRI techniques The thoracic vessels can usually be completely imaged with a T1-weighted spin-echo sequence followed by three-dimensional (3D) gadoliniumenhanced MR angiography. These sequences can be supplemented with a cine gradient-echo technique, using segmented k-space acquisition (Fastcard or Fastcine). Spin-echo and cine gradient echo techniques including segmented k-space acquisition, safety considerations, and sedation requirements have been previously described Contrast-enhanced MR angiography takes advantage of the T1 shortening property of paramagnetic agents (such as gadolinium chelates) and 3D imaging. The advantages of 3D gadoliniumenhanced MR angiography over other MRI techniques for the evaluation of the thoracic vessels include (a) rapid acquisition, (b) ability to image vessels in any plane, and (c) absence of a dephasing artifact. 3D gadolinium-enhanced MR angiography of the thoracic vessels in infants and young children is performed with a nonbreath-hold technique; in older children and adolescents, a breathhold technique can be used. A double dose (0.2 mmol/kg body weight) of gadolinium suffices for optimal visualization of the mediastinal vessels Multiplanar volume reconstructions, as well as maximum intensity projections (MIP) and subvolume MIPs, are obtained in orthogonal and oblique plains to optimally display the vessel of interest. Pulmonary arteries Abnormalities of the pulmonary arteries often occur in association with obstructive lesions of the right ventricular outflow tract (eg, pulmonary artery atresia, stenosis, and hypoplasia), truncus arteriosus and its variants, and pulmonary sling

Effects of Dust Growth and Settling in T Tauri Disks

We present self-consistent disk models for T Tauri stars which include a parameterized treatment of dust settling and grain growth, building on techniques developed in a series of papers by D'Alessio etal. The models incorporate depleted distributions of dust in upper disk layers along with larger-sized particles near the disk midplane, as expected theoretically and as we suggested earlier is necessary to account for mm-wave emission, SEDs, scattered light images, and silicate emission features simultaneously. By comparing the models with recent mid- and near-IR observations, we find that the dust to gas mass ratio of small grains at the upper layers should be < 10 % of the standard value. The grains that have disappeared from the upper layers increase the dust to gas mass ratio of the disk interior; if those grains grow to maximum sizes of the order of mm during the settling process, then both the millimeter-wave fluxes and spectral slopes can be consistently explained. Depletion and growth of grains can also enhance the ionization of upper layers, enhancing the possibility of the magnetorotational instability for driving disk accretion.Comment: 53 pages, 18 figures. To appear in The Astrophysical Journa

CT evaluation of the shoulder in children with Erb's palsy

The majority of children with traumatic injuries of the brachial plexus recover with only minor sequelae. Some patients develop residual deformity, however. This deformity may consist only of internal rotation contractures, but in some patients subluxation of the humeral head may be present. CT is useful in the evaluation of: the presence or absence of subluxation, deformity of the glenoid and the proper placement of the humeral head in plaster or orthotic devices.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46686/1/247_2006_Article_BF02389004.pd

Large skull defect in a headbanger

A mentally retarded self-mutilating child developed a large skull defect at the site of repeated trauma. The bony defect involved only the outer table and had smooth bony margins.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46722/1/247_2004_Article_BF00974046.pd

Congenital tracheal stenosis: Role of CT and high kV films

Congenital tracheal stenosis is an intrinsic narrowing of the tracheal lumen due to complete cartilaginous rings. We evaluated the role of the chest radiograph, high kV films, CT and bronchoscopy in five patients with congenital tracheal stenosis. CT was superior to chest radiography and high kV films in the evaluation of the presence and extent of the stenosis. CT was superior to bronchoscopy in the evaluation of the distal extent of the stenosis in two patients. In addition, CT is useful in ruling out external compression of the trachea by a mass or associated vascular anomaly.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46684/1/247_2006_Article_BF02388158.pd