Expiratory quantitative CT is not as accurate as inspiratory CT for quantifying pulmonary emphysema and probably reflects air trapping more than reduction in the alveolar wall surface.

OBJECTIVE.To

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.

The evaluated parameters remained stable when tube current-time product was reduced from 90 (effective) to 10 (simulated) mAs at multi-detector row CT pulmonary angiography.

The LVIS Junior stent appears safe and effective for endovascular treatment of wide-neck intracranial aneurysms located on small vessels. Midterm results show high rates of adequate and stable occlusion.

Background: In the absence of complications, recipients of lung transplants for cystic fibrosis have normal pulmonary function but the impact of the procedure on the strength and bulk of respiratory and limb muscles has not been studied. Methods: Twelve stable patients who had undergone lung transplantation for cystic fibrosis 48 months earlier (range 8-95) and 12 normal subjects matched for age, height, and sex were studied. The following parameters were measured: standard lung function, peak oxygen uptake by cycle ergometry, diaphragm surface area by computed tomographic (CT) scanning, diaphragm and abdominal muscle thickness by ultrasonography, twitch transdiaphragmatic and gastric pressures, quadriceps isokinetic strength, and quadriceps cross section by CT scanning, and lean body mass. Diaphragm mass was computed from diaphragm surface area and thickness. Results: Twitch transdiaphragmatic and gastric pressures, diaphragm mass, and abdominal muscle thickness were similar in the two groups but quadriceps strength and cross section were decreased by nearly 30% in the patients. Patients had preserved quadriceps strength per unit cross section but reduced quadriceps cross section per unit lean body mass. The cumulative dose of corticosteroids was an independent predictor of quadriceps atrophy. Peak oxygen uptake showed positive correlations with quadriceps strength and cross section in the two groups, but peak oxygen uptake per unit quadriceps strength or cross section was reduced in the patient group. Conclusions: The diaphragm and abdominal muscles have preserved strength and bulk in patients transplanted for cystic fibrosis but the quadriceps is weak due to muscle atrophy. This atrophy is caused in part by corticosteroid therapy and correlates with the reduction in exercise capacity.T he registry of the International Society for Heart and Lung Transplantation indicates that cystic fibrosis (CF) accounts for about one third of all bilateral lung transplantations performed worldwide 1 and, over the last decade, this treatment has become a viable option for the management of many patients with advanced disease. In the absence of complications, transplantation results in dramatic improvements in overall clinical status, health related quality of life, and exercise tolerance. Static and dynamic lung volumes in patients transplanted for CF have been described in detail elsewhere, 4 but only one study has assessed the function of respiratory and limb muscles.5 In this study, maximal static inspiratory and expiratory mouth pressures were reported to be normal and quadriceps strength was reported to be decreased in the seven patients studied, but interpretation of these results was made difficult by the absence of control values. In addition, the strength of individual muscle groups (such as the diaphragm and abdominal muscles) was not assessed specifically, and no measurement of muscle bulk was provided.Better understanding of the cause of muscle weakness is needed to optimise post-transplant rehabilitation strategi...

Thin-section CT depicts ground-glass opacification when effective pulmonary capillary pressure equals critical pulmonary capillary pressure and before a detectable increase in extravascular lung water. Attenuation reflects extravascular lung water.

Expansion of the lung during inspiration results from the coordinated contraction of the diaphragm and several groups of rib cage muscles, and we have previously shown that the changes in intrathoracic pressure generated by the latter are essentially additive. In the present studies, we have assessed the interaction between the right and left hemidiaphragms in anesthetized dogs by comparing the changes in airway opening pressure (DeltaPao) obtained during simultaneous stimulation of the two phrenic nerves (measured DeltaPao) to the sum of the DeltaPao values produced by their separate stimulation (predicted DeltaPao). The measured DeltaPao was invariably greater than the predicted DeltaPao, and the ratio between these two values increased gradually as the stimulation frequency was increased; the ratio was 1.10 +/- 0.01 (P < 0.05) for a frequency of 10 Hz, whereas for a frequency of 50 Hz it amounted to 1.49 +/- 0.05 (P < 0.001). This interaction remained unchanged after the rib cage was stiffened and its compliance was made linear, thus indicating that the load against which the diaphragm works is not a major determinant. However, radiographic measurements showed that stimulation of one phrenic nerve extends the inactive hemidiaphragm toward the sagittal midplane and reduces the caudal displacement of the central portion of the diaphragmatic dome. As a result, the volume swept by the contracting hemidiaphragm is smaller than the volume it displaces when the contralateral hemidiaphragm also contracts. These observations indicate that 1) the left and right hemidiaphragms have a synergistic, rather than additive, interaction on the lung; 2) this synergism operates already during quiet breathing and increases in magnitude when respiratory drive is greater; and 3) this synergism is primarily related to the configuration of the muscle.