Trends in pediatric radiology in the United States.

Long-term trends in pediatric radiology in the United States--in the radiologic care of children, in research, in education and career development, in the Society for Pediatric Radiology, and in the field as a whole--were listed in 1995. The present article attempts to bring those trends up to date for the year 2000 and also describes trends not identified in the earlier report.

Your research: how to get it on paper and in print.

Much worthwhile medical research is never accepted for publication or is ignored when published, often because it is poorly presented. The purpose of this article is to express in simple language how research is best presented in writing. Few actual data are given, though much experience is summarized. The result desired is greater ease, clarity, and effectiveness in communicating medical research. The principles presented here are intended to make medical research writing easier and clearer and to give the research itself more impact.

The effect of the absence of abdominal muscles on pulmonary function and exercise.

In order to determine the long-term sequelae of prune belly syndrome (PBS) and whether the absence of abdominal wall musculature impairs exercise performance we studied nine patients 6 to 31 yr of age with PBS. Conventional spirometry, lung volumes, DLCO, and respiratory muscle strength were measured. A progressive 1-min incremental exercise test was performed on a cycle ergometer, and relative abdominal and chest wall displacements were measured by respiratory inductive plethysmography (RIP). Mean values of TLC, FRC, and RV were 94 +/- 12, 88 +/- 13, and 94 +/- 41%, respectively. Mean values of PEFR, FEV1, and FEF25-75 were 83 +/- 24, 92 +/- 23, and 83 +/- 28%, respectively. Maximal expiratory pressures were significantly reduced in seven of nine patients, with marked reduction in four (>3 SD below the mean). Percent predicted maximal VO2 achieved, % maximal work, and % maximal heart rate were 79 +/- 13, 78 +/- 14, and 87 +/- 2%, respectively. All seven subjects with absent abdominal musculature had paradoxical motion of the abdomen during quiet respiration in the erect or sitting position and while exercising. These subjects had synchronous breathing at rest in the supine position. Although the etiology of the relatively low work rates and VO2 achieved was multifactorial, we speculate that the abdominal paradox in these subjects necessitates abnormally large rib cage displacements during exercise, which may be a significant contributing factor to exercise limitation in some of these subjects.

Prospective evaluation by computed tomography and pulmonary function tests of children with mediastinal masses.

BACKGROUND: Our ability to predict respiratory compromise during general anesthesia in a child with an anterior mediastinal mass is limited. Two prior reports have found a correlation between adequacy of ventilation during general anesthesia and the tracheal cross-sectional area obtained from computed tomograms (computed tomography [CT] scans). These and other reports have suggested that pulmonary function tests may provide additional information regarding anesthetic risks, but no studies have evaluated the extent of respiratory compromise in children with an anterior mediastinal mass. METHODS: We prospectively evaluated 31 children with mediastinal masses before 34 surgical procedures. At each evaluation the tracheal area (as a percent of the predicted area on the basis of age and gender) was determined by CT. Pulmonary function tests were performed in the sitting and supine positions. The eleven children with either a tracheal area or peak expiratory flow rate (PEFR) of less than 50% of predicted received only a local anesthetic; the majority of children above these levels (17 of 22) received a general anesthetic. RESULTS: Eleven of 31 patients had significant pulmonary restriction as defined by total lung capacity of less than 75% of predicted. Eight patients had a PEFR in the supine position of less than 50% of predicted. PEFR was lower in the supine than the upright position in all patients (median value of decrease, 12%). In 28 of 34 evaluations the child had a tracheal area greater than 50% of predicted, a criterion proposed for safe utilization of general anesthesia. This latter guideline, however, did not identify all patients with significant impairment of pulmonary function; five patients had a PEFR of less than 50% of predicted but tracheal areas of greater than 50% of predicted. All children were administered anesthetics uneventfully with these guidelines. CONCLUSIONS: Although the tracheal area can be accurately measured with the CT scan, this does not identify all children with mediastinal masses and abnormal pulmonary function. A large mass may produce significant restrictive impairment and hence reduction in PEFR by the intrathoracic volume it occupies and yet not cause tracheal compression. It may also reduce the PEFR by narrowing the bronchi distal to the carina. Currently no CT standards exist for measuring bronchial areas in children. Our study did not evaluate whether impaired pulmonary function as measured by PEFR would be predictive of respiratory collapse during general anesthesia because all were excluded and operated on under local anesthesia. General anesthesia was well tolerated in children with tracheal area and PEFR greater than 50% of predicted. Pulmonary function tests in children with anterior mediastinal masses may add valuable information to the anatomic evaluation obtained by CT scan.

The rise and fall of a radiologic technique.

As young radiologists read the slightly self-satisfied articles celebrating the centennial of radiology, they may conclude that the course of radiology and all its components has been smoothly upward, without hesitations, false starts, or disappointments. Older radiologists know better. The replacement of a less satisfactory technique with a better one is a gain for both patients and physicians, but the replacement process itself can be distressing. Much of what radiology residents learned in the 1950s and 1960s is no longer of any use. Who now employs pneumoencephalography or intravenous cholangiography? Entire books were once written about these procedures [1, 2]. Who can now credit the reliance once placed on positive-contrast maxillary antrography [3]? Few have even heard of eustachian tubography [4]. Radiologists who tried to make a career using those techniques learned to their sorrow that although anatomy is permanent and diseases change only slowly, techniques are often ephemeral. Total body opacification, a technique once of consuming interest to the present writers [5-7], is an illustration of this.

Trends in papers presented at meetings of the Society for Pediatric Radiology.

The abstracts of papers presented at the 1959-1994 meetings of the Society for Pediatric Radiology were reviewed and tabulated for organ system and imaging modality chiefly discussed and for number of authors per paper. Among organ systems, the musculoskeletal system and extremities were favored at first, then relatively ignored, then favored again. Interest in the central nervous system and head has been at a high level for the last decade. In modalities, plain radiography and fluoroscopy were dominant for more than 20 years but have now fallen to a much lower level of interest. Ultrasonography, magnetic resonance imaging, and computed tomography have passed all the older techniques and, collectively, have accounted for a large majority of the presentations for the last decade. Changes have been much greater in imaging techniques employed than in organ systems discussed. The number of authors per paper presented grew from 1.0 in 1959 to 1.7 for the 1960-1964 period to 4.1 for the 1990-1994 period.

Diseases of the trachea, bronchi, and smaller airways.

Except in the fetus, life depends on the integrity of the airways. This article describes ways in which that integrity can be threatened in childhood.

Caldwell Lecture. Respiratory problems of early life now allowing survival into adulthood: concepts for radiologists.

Many patients with illnesses that once were fatal at birth or during childhood now survive into adult life. This article considers four respiratory illnesses of early life in which long-term survival now occurs frequently: cystic fibrosis, diaphragmatic hernia, esophageal atresia-tracheoesophageal fistula, and bronchopulmonary dysplasia. In cystic fibrosis, although the median age at death is now 25 years, chronic pulmonary infection due ultimately to the abnormal composition and clearance of airway mucus is still the usual cause of death. Earlier survivors of congenital diaphragmatic hernia had only minor diminution of perfusion and ventilation of the lung on the side of the hernia as adolescents or young adults; however, as infants with greater degrees of pulmonary hypoplasia have successful repair of their hernias, more long-term respiratory impairment will probably be found. The esophageal atresia tracheoesophageal fistula complex leaves all esophagi and many tracheas permanently abnormal; recurrent aspiration, repeated pneumonia, and an unduly collapsible trachea are the result, although symptoms may be few. Survivors of bronchopulmonary dysplasia have decreased exercise capacity, wheezing, and recurrent pneumonia, although their chest radiographs may become normal or almost normal.