PubMed Health⌕ Search

Biomedical subjects

A M Hubbard

Publications and source records attributed to A M Hubbard.

At least 37 records · Page 2Linked to original sources
PubMed1998

Anomalies and malformations affecting the fetal/neonatal chest.

Although significant anomalies of the fetal thorax are uncommon, with improvement in high-resolution ultrasonography, more of these lesions are being diagnosed prenatally. Accurate and specific prenatal diagnosis is important because different lesions have different natural histories and prognosis. Prenatal MRI is an increasingly important adjunct for identification and differentiation of these lesions and may help determine in selected cases when and if in utero fetal intervention is indicated.

Bronchopulmonary Sequestration↗
PubMed1998

Prenatal MRI evaluation of giant neck masses in preparation for the fetal exit procedure.

Airway compromise at birth can be anticipated with giant neck masses, so that as much anatomic information as possible is necessary prior to delivery to establish a diagnosis and assess the airway. With this study, we evaluated the usefulness of prenatal magnetic resonance imaging (MRI) for evaluation of giant fetal neck masses prior to operating on placental support, the Ex Utero Intrapartum Treatment (EXIT) procedure, performed to secure the neonatal airway. Three pregnant women with an ultrasound (US) diagnosis of fetal giant neck mass were referred for prenatal MRI. As this was our initial experience performing prenatal MRI, a variety of imaging sequences were used including spin-echo, fast gradient-echo, half-fourier single shot turbo spin-echo (Haste), and echo-planar imaging (EPI). All sequences performed were able to demonstrate the fetal airway relative to the mass. In addition, the images were able to give a more global definition of the mass because of the larger field of view than could be obtained with MRI compared to US. The Haste sequence provided the best definition of a mass because of decreased motion artifacts. The prenatal diagnosis on MRI was teratoma in two and lymphangioma in one and was confirmed at birth. MRI provided essential information about the diagnosis and the anatomy of the giant neck masses and adjacent airway in three fetuses prior to selection for the EXIT surgical procedure.

Airway Obstruction↗
PubMed1998

The pediatric foot and ankle.

MR imaging can be extremely helpful in evaluating congenital and acquired deformities of the foot and ankle. Knowledge of the normal developmental anatomy of the foot and ankle is important to accurately identify abnormalities versus normal variants. The foot and ankle may be abnormal because of trauma, infection, tumor, or systemic disease. MR imaging can help in the differential diagnosis of abnormalities as well as in treatment planning and follow-up.

Adolescent↗
PubMed1997

MRI of the pediatric shoulder: nontraumatic lesions.

Magnetic resonance imaging is an established technique for imaging the shoulder because it demonstrates clearly the articular surfaces, medullary canal and the extra-articular soft tissues which can be affected in shoulder disorders. The value of MR imaging in the evaluation of the traumatized shoulder has been described [1]; however, few cases of MR imaging in nontraumatic disorders in children have been reported. We reviewed the findings in 55 children undergoing MRI of the shoulder for nontraumatic conditions and included selected cases showing a broad range of imaging findings.

Adolescent↗
PubMed1997

Intrapartum airway management for giant fetal neck masses: the EXIT (ex utero intrapartum treatment) procedure.

OBJECTIVE: Our goal was to review our experience with the EXIT (ex utero intrapartum treatment) procedure in the management of five cases with life-threatening fetal neck masses. STUDY DESIGN: We present a retrospective review of prenatal presentation and course, diagnostic accuracy of imaging studies, intraoperative management, complications, and outcomes. RESULTS: Polyhydramnios was the initial presenting symptom in three of five fetuses with a mean gestational age of 25 +/- 6 weeks. Preterm labor occurred in two patients. Fetal magnetic resonance imaging provided accurate diagnosis in all four cases whereas conventional ultrasonography led to the diagnosis in four of five cases. The mean duration of EXIT was 28 +/- 22 minutes. The mean venous cord blood gas values were pH 7.22 +/- 0.05, PCO2 61 +/- 11 mm Hg, and PO2 42 +/- 8 mm Hg. In four of five cases an airway was successfully secured. CONCLUSIONS: The EXIT procedure provides up to 1 hour of good uteroplacental support and is the procedure of choice to secure an airway in the fetus with a giant neck mass.

Airway Obstruction↗
PubMed1997

Effect of surgical reconstruction on flow profiles in the aorta using magnetic resonance blood tagging.

BACKGROUND: The aorta that has undergone an aorta-pulmonary artery anastomosis may not exhibit the same velocity profile as the nonreconstructed aorta, whose velocity profile is thought to be uniform across the vessel diameter (plug flow). This may have an impact on fluid dynamics and will alter Doppler flow calculations. Our objective was to determine the impact of surgical reconstruction on the velocity and flow profiles of the reconstructed ascending and descending aorta. METHODS: Using a magnetic resonance imaging tagging technique that labels flowing blood (bolus tagging), we studied 22 patients (mean age, 8.6 +/- 4.7 years) who had had a Fontan procedure. A cine sequence labeled the blood and acquired the image after 20 ms in the middle of the ascending aorta and behind the left atrium in the descending aorta. The repetition time was 50 ms. RESULTS: The reconstructed ascending aorta displayed a velocity profile skewed anteriorly, whereas in the nonreconstructed aorta, the velocity profile was flat. Reconstructed aortas also displayed flows that were higher anteriorly, took a longer time to reach maximum velocity, and were less like "plug" flow than the nonreconstructed aorta. The descending aorta, regardless of whether aortic reconstruction was present, displayed velocity profiles (at various phases of systole) skewed posteriorly. CONCLUSIONS: The reconstructed aorta displays disturbed flow, and the velocities across the ascending aortic diameter are more varied than those in aortas without reconstruction and are skewed anteriorly. The descending aortic velocity profile in children is skewed posteriorly, regardless of whether aortic reconstruction is present. This information may help design and build a "better" aortic reconstruction.

Adolescent↗
PubMed1997

Left-sided congenital diaphragmatic hernia: value of prenatal MR imaging in preparation for fetal surgery.

PURPOSE: To evaluate the usefulness of prenatal magnetic resonance (MR) imaging in determination of the position of the fetal liver and amount of lung tissue in left-sided congenital diaphragmatic hernia. MATERIALS AND METHODS: In three pregnant women, MR imaging was performed with a 1.5-T magnet and fast gradient-echo, half-Fourier single-shot turbo spin-echo, and echo-planar sequences. MR imaging findings were compared with those from ultrasound (US) performed the same day. The fetuses were 20, 23, and 32 weeks gestational age. RESULTS: The fetal liver was demonstrated in the chest in all three fetuses with MR imaging and in only one fetus with US. The best images of the fetal liver were obtained with a T1-weighted gradient-echo sequence. The best images of the entire fetus were obtained with a half-Fourier single-shot turbo spin-echo sequence. CONCLUSION: In these fetuses, MR imaging proved important by clearly demonstrating herniation of fetal liver into the chest, thereby changing family counseling and prenatal care.

Counseling↗
PubMed1996

Innominate artery compression of the trachea in infants.

Compression of the airway by the innominate artery has been a controversial cause of stridor and apnea in infants. Magnetic resonance imaging has been applied to document the possible association of segmental tracheomalacia. Forty infants with symptoms of stridor were studied, 7 of 40 infants aged 3-21 months (mean 10 months) had innominate artery compression on the trachea. Five infants were treated conservatively and two infants underwent surgery. Flattening of the trachea was longer than the mass compression point by the innominate artery. Therefore, intrinsic abnormality of the trachea is the basis of the respiratory symptom.

Airway Obstruction↗
PubMed1996

Magnetic resonance imaging of skewfoot.

Magnetic resonance imaging was used to visualize the ossified and unossified portions of the bones and soft tissues of the feet in order to evaluate the tarsometatarsal anatomy in sixteen children, three months to six years old (mean, fifteen months old), who were seen in the orthopaedic clinic with a suspected diagnosis of skewfoot. Twenty-seven feet were clinically abnormal and five were normal. Of the abnormal feet, twenty-six had a radiographic diagnosis of skewfoot and one, of simple metatarsus adductus. Of the skewfeet, seven had a talocalcaneal angle of 45 degrees or more as measured on the lateral radiograph and six had a talocalcaneal angle of 45 degrees or more as measured on the anterior radiograph. Valgus deformity of the hindfoot was not apparent on clinical examination in any of the children. The talocalcaneal angles measured on the magnetic resonance images corresponded poorly with those measured on the radiographs, possibly because it is not possible to simulate weight-bearing during magnetic resonance imaging or because the effect of partial volume averaging on thin sections. However, magnetic resonance imaging demonstrated the shapes of the bones and the positions of the unossified portions of the bones. Magnetic resonance imaging showed lateral subluxation of the navicular in twenty-four skewfeet, plantar subluxation in ten, and medial subluxation of the first metatarsal on the medial cuneiform in twenty-five. The alignment of the lateral margin of the calcaneus and cuboid on the magnetic resonance images was normal in all patients. Magnetic resonance imaging has the unique ability to show the cartilaginous and ossified portions of the developing bones of the foot.

Child↗
PubMed1995

Ovarian torsion: clinical and imaging presentation in children.

Ovarian torsion is uncommon and has a nonspecific clinical presentation. To determine the impact of imaging on clinical management, the authors reviewed their recent experience with 12 children who had a total of 13 episodes of ovarian torsion. Three children presented as neonates, six were premenarchal, and three were postmenarchal. Ultrasound was the imaging study of choice. In all three neonates, ultrasonography showed complex abdominopelvic cysts indicating the need for surgery. In five of 10 episodes in older patients, ultrasonography showed a solid mass with an appearance strongly suggestive of torsion. Same-day surgery was performed in three patients, and the involved ovary was salvaged in one. Another patient had a small piece of normal-appearing ovary left in situ. This low rate of ovarian salvage is attributable to the combination of delay in patient presentation and surgical delay owing to the often nonspecific clinical and imaging presentation of ovarian torsion. A high level of clinical suspicion, expeditious imaging, and familiarity with the varied clinical and imaging presentations of ovarian torsion should decrease the surgical delay and improve the likelihood of ovarian salvage.

Adolescent↗
PubMed1995

Evaluation of developmental dysplasia, Perthes disease, and neuromuscular dysplasia of the hip in children before and after surgery: an imaging update.

This article focuses on the current status of radiologic imaging before and after surgery of a limited spectrum of common hip disorders in children: developmental hip dysplasia, Legg-Calvé-Perthes disease, and neuromuscular hip dysplasia. An understanding of the anatomic abnormality, of when surgical intervention is needed, of the types of surgery, and of the complications influences the ability of the radiologist to interpret radiologic studies and to communicate information to the referring physician. Technologic advances in imaging that provide new information about the developing hip and standard radiographic evaluation of the abnormal hip are discussed. The diagnostic and treatment goals for all types of hip disease are similar. The goals of all therapy are to preserve the full range of motion of the hip and to prevent premature degenerative changes by maintaining a round, well-shaped femoral head that is contained by and congruous with the acetabulum.

Child↗
PubMed1994

Magnetic resonance imaging of airway obstruction resulting from vascular anomalies.

Accurate diagnosis is important in the evaluation of airway disorders of infants and children. Today, multiple imaging techniques are available to evaluate the pediatric airway. We performed magnetic resonance (MR) imaging of the airway in 16 infants and children with symptoms of airway obstruction. Fourteen of 16 patients symptoms were related to compression of the airway by vascular structure. MR imaging was useful in the diagnosis and management of these patients without the need for more invasive procedures.

Aorta↗
PubMed1994

Magnetic resonance and echocardiographic imaging of pulmonary artery size throughout stages of Fontan reconstruction.

BACKGROUND: Because pulmonary artery size is considered by most investigators to be a major prognosticator of outcome in patients undergoing staged Fontan reconstruction, the objective of the present study was to determine the efficacy of noninvasive measures in determining pulmonary artery size. METHODS AND RESULTS: This study analyzed the T1-weighted, spin-echo magnetic resonance and echocardiographic images of 36 functional single-ventricle patients throughout stages of Fontan reconstruction (prebidirectional and postbidirectional cavopulmonary anastomosis and after Fontan) and compared them with angiography images at cardiac catheterization. Magnetic resonance imaging had a high degree of agreement with angiography, with the McGoon index agreeing better than the Nakata index and absolute right and left pulmonary diameters. Although echocardiography had fair agreement with angiography, it agreed less well and had a wider standard deviation than magnetic resonance imaging for all indexes and measurements and, based on the prediction interval, would be a poorer prospective measure of pulmonary artery size in this population. In addition, echocardiography was a poorer measure of pulmonary artery size as the size of the vessel increases. Magnetic resonance imaging correctly detected five of five patients with nonconfluent branch pulmonary arteries and six of six patients with stenoses, whereas echocardiography was unable to visualize any of the patients with nonconfluent branch pulmonary arteries with certainty and only two of six (33%) with stenoses. CONCLUSIONS: Magnetic resonance imaging is a useful, noninvasive tool to determine pulmonary artery size in patients undergoing Fontan reconstruction and is superior to echocardiography. Echocardiography was a fair predictor of pulmonary artery size, but magnetic resonance imaging agreed with angiography better than echocardiography and outperformed echocardiography in diagnosing branch pulmonary artery discontinuity and stenoses. Magnetic resonance imaging may avoid unnecessary cardiac catheterization, especially in older patients, and may obviate the need for jugular or subclavian catheterization in those who have undergone bidirectional cavopulmonary anastomosis.

Adolescent↗
PubMed1993

Sonography of the knee in normal and abused infants.

Sonography of an infant's knee is relatively easy and can show the non-ossified cartilage and adjacent soft tissues with great clarity. The normal anatomic features are characteristic and easy to learn and recognize. In abused infants, sonograms can confirm subtle or questionable radiographic abnormalities. In infants with metabolic bone disease, detection of occult fractures of the epiphyses is clinically important. Metaphyseal abnormalities due to neonatal ricktes should not be mistaken as signs of child abuse.

Child Abuse↗