The radiological assessment of diaphragmatic function has traditionally relied upon plain radiography and erect fluoroscopy.' Information about hemidiaphragmatic movement from plain radiography is limited because of the wide normal variability of hemidiaphragmatic position,2 while fluoroscopy is complicated both by conflicting reports of side to side variability23 and an apparent 6% incidence of paradoxical movement on sniffing in normal subjects.3 Ultrasound scanning is an accepted qualitative method of assessing hemidiaphragms -for example, subpulmonary effusions, subphrenic collections' and, more recently, traumatic rupture45 and pleural masses.' We have evaluated ultrasound scanning as a quantitative method of assessing hemidiaphragmatic movement in normal subjects.7 The normal ranges of craniocaudal excursion of the posterior hemidiaphragm (both in tidal and maximum voluntary respiration), and the right to left variability were determined, and acceptable reliability of the technique in terms of the interobserver and intraobserver reproducibility was shown. Using erect fluoroscopy it has been shown that the anterior part of the hemidiaphragm moves approximately 40% less than the posterior part, and that the mean axial motion is linearly related to the volume displacement of the diaphragm as measured by both respiratory induction plethysmography (Respitrace) and fluoroscopy in the erect position.8 This conflicts with the results of a study of the diaphragm using magnetic resonance imaging (MRI) in the supine position.9The aims of this study were to determine the relation of the posterior diaphragmatic excursion and inspired volume as measured by simultaneous ultrasound scanning and waterbath spirometric testing, to examine the variability of this relation in a normal group of subjects, to observe any difference in changing posture, and to assess the reproducibility of the relationship. Methods SUBJECTSFourteen healthy subjects with a wide range in age and body habitus (table 1), unpractised in 500 on 10 April 2019 by guest. Protected by copyright.

No abstract

Respiratory dysfunction is an important complication of acute stroke but its mechanisms are poorly understood. Previous indirect assessments suggest that paralysis of the diaphragm occurs contralateral to the cerebral lesion. Diaphragmatic excursion was studied with real time ultrasound during quiet and deep breathing in 50 patients within 72 hours of acute stroke and 40 controls. During quiet breathing, hemidiaphragmatic movements were not significantly different between right hemispheric stroke, left hemispheric stroke, and controls. During deep inspiration, there was a significant bilateral reduction in hemidiaphragmatic excursion in patients with stroke, for both right hemispheric stroke and left hemispheric stroke when compared with controls (both P < 0 001). Thus isolated hemidiaphragmatic paresis does not occur but maximal excursion of the diaphragm is reduced bilaterally in patients with acute stroke. This is a likely contributor to the respiratory dysfunction after acute stroke. (J Neurol Neurosurg Psychiatry 1995;58:738-741)

Recent improvements in MR image acquisition and post-processing techniques have allowed quantitative kidney volume measurements to be derived from patient studies. These morphological indices can provide "snapshot" assessments that may be related to kidney function. The study objective was to measure cortical and total kidney volumes in patients with renovascular disease (RVD) using contrast-enhanced MR angiography (CE-MRA) in order to assess the reproducibility of the technique and to investigate associations between volumes and renal function as measured by glomerular filtration rate (GFR) calculations. 50 patients with RVD were scanned using CE-MRA. Kidney lengths, volumes and renal artery stenoses (RAS) were evaluated, and GFR was calculated using clinical formulae and nuclear medicine isotope renography. Mean MRI kidney lengths were 10.3+/-0.2 cm, and mean MRI volumes were 74.9+/-3.6 cm3 (cortical) and 128.5+/-5.3 cm3 (total). Kidneys supplied by moderately stenosed arteries had enlarged lengths and volumes, whilst those supplied by severely stenosed arteries had significantly smaller lengths (p<0.001) and volumes (p<0.001). There was a clear association between MRI cortical volume and GFR (r = 0.74, p<0.001, n = 48), but less so between kidney length and GFR (r = 0.54, p<0.001, n = 48). For individual patients, left/right cortical volume differences were small provided that severe RAS was not present, but large left/right volume differences and a GFR reduction were noted when severe RAS was present. The cortical volume distribution provides a useful single-timepoint indication of kidney function as defined by GFR, with no additional data acquisition required other than that of standard CE-MRA examination.

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