We have used three-dimensional reconstructions obtained with spiral computed tomography to measure total diaphragm length (L di ) and surface area (A di ), the length (L do ) and surface area (A do ) of the dome, and the length (L ap ) and surface area (A ap ) of the zone of apposition in 10 hyperinflated patients with severe chronic obstructive pulmonary disease, or COPD (FEV 1 ϭ 27% predicted: FRC ϭ 225% predicted) and 10 normal subjects matched for age, sex, and height. Measures of L di , A di , L ap , and A ap decreased linearly between FRC and TLC in the two groups, but L do and A do did not change. On average, patients' A di and A ap at FRC were reduced to 73% and 54% of normal values, whereas A do was unaffected. When compared at similar absolute lung volumes, mean diaphragm dimensions were similar in patients with COPD and normal subjects, but individual values were very variable in both groups. This variability was partly accounted for by differences in body weight: i.e., the greater the weight, the longer the diaphragm. We conclude that ( 1 ) patients with COPD have marked reductions in A di and A ap at FRC but have diaphragm dimensions similar to those of normal subjects when compared at similar absolute lung volumes, and ( 2 ) normal subjects and patients with COPD show substantial intersubject variability in diaphragm dimensions that is partly explained by differences in body weight. In patients with chronic obstructive pulmonary disease (COPD), hyperinflation of the lungs decreases the operating length of the diaphragm. As a result, the inspiratory function of the muscle is impaired. The magnitude of diaphragm shortening increases with the degree of hyperinflation, and it is generally assumed that, at a given absolute lung volume, diaphragm length and surface area are similar in patients with COPD and normal subjects.However, very few studies have investigated the effect of chronic hyperinflation on diaphragm dimensions. In two early studies using chest radiographs, Sharp and colleagues (1) reported that the diaphragm was 40% shorter at FRC in patients with COPD than in normal subjects, and Rochester and Braun (2) showed that diaphragm length was reduced by 28% in patients with COPD at residual volume (RV) compared with normal subjects at their RV; this difference, however, disappeared when diaphragm lengths were compared at similar absolute lung volumes. Interpretation of these results is difficult because measurements of diaphragm dimensions were obtained from two-dimensional analysis of chest radiographs, were generally performed at a single lung volume, and were not always compared with measurements obtained in adequately matched controls.In a previous study (3), we have described a technique of three-dimensional (3D) diaphragm imaging using spiral computed tomography (CT) that allowed accurate measurements of diaphragm length and surface area. In the present work, we have used this technique to compare diaphragm dimensions at different lung volumes in 10 hyperinflated patients with severe COPD...

Inspiratory muscle weakness due to lung hyperinflation and muscle wasting may occur in cystic fibrosis. We therefore measured diaphragm function and bulk in 18 stable patients with cystic fibrosis and 15 matched control subjects; the abdominal and quadriceps muscles were studied for comparison. We assessed diaphragm mass, abdominal muscle thickness, twitch transdiaphragmatic and gastric pressures, quadriceps cross-section and isokinetic strength, and lean body mass. Lean body mass, quadriceps strength, and quadriceps cross-section were lower in patients with cystic fibrosis. Twitch transdiaphragmatic pressure was 23% lower and twitch gastric pressure was 22% greater in patients with cystic fibrosis than in control subjects, but diaphragm mass and abdominal muscle thickness were similar in the two groups. For any given lean body mass and quadriceps cross-section, patients with cystic fibrosis had greater diaphragm mass and abdominal muscle thickness. Diaphragm mass had greater intersubject variability in patients with cystic fibrosis than in control subjects. We conclude that diaphragm strength is decreased but abdominal muscle strength is increased in patients with cystic fibrosis. Diaphragm and abdominal muscle bulk are not affected by the general muscle wasting, which suggests that there may be a training effect of cystic fibrosis on respiratory muscles. However, the variability of diaphragm mass indicates that this beneficial response does not occur in all patients with cystic fibrosis.

Objectives To investigate the correlation between fetal lung volume (FLV), measured with magnetic resonance imaging (MRI), and postnatal mortality in newborns with prenatally diagnosed isolated congenital diaphragmatic hernia (CDH). Methods

Objectives To identify important factors in the differential diagnosis of renal cysts associated with hyperechogenic kidneys. Methods

Objective To compare the diagnostic accuracy of twodimensional (2D) ultrasound and three-dimensional (3D) computed tomography (CT) for the diagnosis of fetal skeletal anomalies. Methods