Bennett A. Alford

Hyperpolarized 3He MR lung ventilation imaging in asthmatics: Preliminary findings

Asthma is a disease characterized by chronic inflammation and reversible obstruction of the small airways resulting in impaired pulmonary ventilation. Hyperpolarized 3He magnetic resonance (MR) lung imaging is a new technology that provides a detailed image of lung ventilation. Hyperpolarized 3He lung imaging was performed in 10 asthmatics and 10 healthy subjects. Seven asthmatics had ventilation defects distributed throughout the lungs compared with none of the normal subjects. These ventilation defects were more numerous and larger in the two symptomatic asthmatics who had abnormal spirometry. Ventilation defects studied over time demonstrated no change in appearance over 30–60 minutes. One asthmatic subject was studied twice in a three‐week period and had ventilation defects which resolved and appeared in that time. This same subject was studied before and after bronchodilator therapy, and all ventilation defects resolved after therapy. Hyperpolarized 3He lung imaging can detect the small, reversible ventilation defects that characterize asthma. The ability to visualize lung ventilation offers a direct method of assessing asthmatics and their response to therapy. J. Magn. Reson. Imaging 2001;13:378–384.

Radiographic measurements of dysplastic adult hips.

Abstract Hip dysplasia is a not uncommon feature in adults and can vary from subtle acetabular dysplasia to complex sequelae of developmental dysplasia of the hip. This review article describes the most useful radiographic measurements used to evaluate the adult hip. The frontal projection of the pelvis permits measurement of the center-edge angle (CE angle) and ”horizontal toit externe” angle (HTE angle), both of which assess the superior coverage of the acetabulum. The femoral neck-shaft angle (NSA) is also measured on this view. The false profile radiograph of the pelvis is described. It allows measurement of the vertical-center-anterior angle (VCA angle), which determines the anterior acetabular coverage and detects early degenerative hip joint disease. When surgery is contemplated, computed tomography (CT) is useful to better determine the anterior acetabular coverage by use of the anterior acetabular sector angle (AASA), and the posterior acetabular coverage by use of the posterior acetabular sector angle (PASA). CT also permits measurement of femoral anteversion. These measurements are particularly useful in the evaluation of acetabular dysplasia and for the preoperative assessment of the dysplastic hip.

Pleuroperitoneal shunts in the management of neonatal chylothorax

Pleuroperitoneal shunts have been placed in five ventilator-dependent newborns with persistent chylothorax. The etiology of the chylothorax appeared to be secondary to superior vena caval obstruction in three patients and was idiopathic in the remaining two. Despite traditional therapies these infants were on a progressively deteriorating clinical course. Hakim-Cordis low-pressure ventricular-peritoneal shunt catheter systems were used in each infant. Ultrasonography was used to follow the regression of pleural effusions and to determine the need for shunt compression. Shunt patency was confirmed with radionuclide studies. Four of five infants had a complete resolution of their chylothorax and pulmonary insufficiency. Three of these infants were extubated within 28 days following the placement of the shunt. Nutritional and metabolic stability was rapidly achieved. The shunts were removed several weeks later without recurrence of the chylothorax. A fifth infant failed to improve after the placement of the pleuroperitoneal shunt and died of progressive pulmonary insufficiency. The placement of pleuroperitoneal shunts in infants with refractory chylothorax is safe, technically easy to perform, and is associated with few complications.

Prevalence of deep venous thrombosis in the lower extremities of children in the intensive care unit

AbstractPurpose. To determine the prevalence of lower extremity deep venous thrombosis (LE-DVT) in children who spent at least 72 h in the pediatric intensive care unit (ICU). Materials and methods. Children up to the age of 17 years who spent at least 72 h in the ICU underwent lower extremity venous ultrasound at the end of their stay. Prevalence range for the sample size was calculated with a confidence interval of 95%. Results. Among 76 children who spent 3–141 days in the ICU, the prevalence of acute (and silent) DVT was 4 % (confidence interval 0–9 %). All three affected children had femoral venous catheters in that leg during their ICU stay (17 unaffected children also had catheters). Conclusion. Children in an ICU setting are at significantly lower risk for thrombosis than adults in the same setting.

Chondrodysplasia punctata stemming from maternal lupus erythematosus.

The finding of stippled epiphyses on a neonatal radiograph generates a wide differential diagnosis, including genetic and teratogenic causes. We report the case of a male infant with stippled epiphyses evident on neonatal radiographs in whom a typical rash of lupus erythematosus developed. The skin abnormalities in the infant resulted in a diagnosis of systemic lupus erythematosus in his mother. Over a 3-year follow-up period, the child has demonstrated strikingly short stature, midface hypoplasia, anomalous digital development, slow resolution of the stippled epiphyses, and near normal cognitive development. The differential diagnosis of chondrodysplasia punctata and the literature supporting maternal lupus as one cause are reviewed.

Overhead Throwing Injuries of the Shoulder and Elbow

Injuries to the shoulder and elbow are common in athletes involved in sporting activities that require overhead motion of the arm. An understanding of the forces involved in the throwing motion, the anatomic structures most at risk, and the magnetic resonance imaging appearances of the most common associated injuries can help to improve diagnostic accuracy when interpreting imaging studies in these patients.

Intracranial bleeding from child abuse: The value of skull radiographs

Two infants with intracranial bleeding are described. Each had extensive evaluations aimed at uncovering vascular anomalies or bleeding diatheses. Plain skull radiographs that demonstrated fractures led to the correct diagnosis of child abuse. This report serves to emphasize the value of the plain skull radiograph in the evaluation of infants with intracranial bleeding.

Shoulder MR Arthrography: Intraarticular Anesthetic Reduces Periprocedural Pain and Major Motion Artifacts but Does Not Decrease Imaging Time

PURPOSE To prospectively determine whether the addition of an intraarticular anesthetic to the magnetic resonance (MR) arthrography solution has an effect on periprocedural pain, motion artifacts, and imaging time. MATERIALS AND METHODS This study was approved by the institutional review board, and written informed consent was obtained from all patients. From September 2009 to March 2010, 127 patients, most imaged for shoulder pain, were randomized into two groups. The first group (group A, 63 patients) received intraarticular injection of gadopentetate dimeglumine, ropivacaine 0.5%, and normal saline in a ratio of 1:100:100. The second group (group B, 64 patients) received intraarticular injection of gadopentetate dimeglumine and normal saline in a ratio of 1:200. Pain was assessed before and after injection and immediately after 1.5-T MR imaging and rated on a scale of 0 to 10. Motion artifact was assessed by two musculoskeletal radiologists and two fellows by using a scale of 0 to 3 (0=no artifact, 1=artifact present but not affecting diagnostic image quality, 2=artifact present and diminishing diagnostic image quality, and 3=artifact present and rendering image nondiagnostic). MR imaging time and examinations with repeated sequences were recorded. Wilcoxon rank sum, analysis of covariance, and permutation data analyses were performed. RESULTS The mean pain levels before injection, after injection, and after MR imaging were 3.5, 2.3, and 2.5, respectively, for group A and 3.6, 3.1, and 3.2 for group B. After adjusting for age, sex, and preinjection pain level, the mean differences in pre- and postinjection pain and preinjection pain and post-MR imaging pain between the two groups were -0.9 (P=.017) and -0.8 (P=.056), respectively. No significant difference in mean total MR imaging time or number of patients with repeat sequences was noted. Radiologists 1 and 2 recorded grade 2 or 3 motion in six and five patients, respectively, in group A and 15 and 14 patients, respectively, in group B (P=.047 and .048, respectively). Radiologists 3 and 4 recorded grade 2 or 3 motion in 13 and 23 patients, respectively, in group A and 23 and 33 patients, respectively, in group B (P=.093 and .110, respectively). CONCLUSION The use of an intraarticular anesthetic significantly reduces periprocedural pain and major motion artifacts associated with MR shoulder arthrography; however, total MR imaging time is not reduced.

Comparison of adaptive linear interpolation and conventional linear interpolation for digital radiography systems

Some large field digital radiography systems are currently under development using multiple detectors. These small size two dimension detectors are abutted together to cover a large field. Physical gaps existing between adjacent detectors produce seams between the resultant subimages. In this paper, an adaptive linear interpolation algorithm was introduced for estimating missing information at the seams and was compared with conventional linear interpolation and with nonlinear interpolation. The effectiveness of the algorithms was evaluated for relative/absolute errors. Phantom images were acquired using prototype digital radiography systems. Seams with width ranging from two pixel to six pixel were introduced and adaptive linear interpolation algorithms were applied to estimate missing information at the seams. Quantitatively, the adaptive interpolation offers at least equivalent or less error than that of the linear interpolation algorithm. The experimental results prove that there is a significant difference between two algorithms for tested radiographic images. The comparison results also show that the adaptive interpolation offers better performance than nonlinear interpolation. When developing large field digital radiography imaging systems, gaps between adjacent detectors should be minimized. For narrow seams, the adaptive linear interpolation algorithm is a practical solution because of its simplicity and effectiveness.

Cervical spine anomalies and tumors in Weaver syndrome.

Weaver syndrome is an autosomal dominant disorder comprising accelerated growth rate and rapidly advancing skeletal maturation. Previous reports suggest that the phenotype in adults may be sufficiently subtle to make diagnosis difficult. Half brothers with classical childhood findings of Weaver syndrome and their father with minimal clinical findings showed cervical spine anomalies that likely represent a consistent radiographic finding in this disorder. One of the children represents the third occurrence of neoplasia in Weaver syndrome.