This large international radiation dose survey demonstrates considerable reduction of radiation exposure in coronary CTA during the last decade. However, the large inter-site variability in radiation exposure underlines the need for further site-specific training and adaptation of contemporary cardiac scan protocols.
• Coronary artery disease (CAD) is a major cause of morbidity and mortality. • Invasive coronary angiography (ICA) is the reference standard for detection of CAD. • Noninvasive computed tomography angiography excludes CAD with high sensitivity. • CT may effectively reduce the approximately 2 million negative ICAs in Europe. • DISCHARGE addresses this hypothesis in patients with low-to-intermediate pretest probability for CAD.
Using magnetic resonance imaging (MRI) in conjunction with
synchronized spirometry we analyzed and compared diaphragm
movement during tidal breathing and voluntary movement of the
diaphragm while breath holding. Breathing cycles of 16 healthy
subjects were examined using a dynamic sequence (77 slices in
sagittal plane during 20 s, 1NSA, 240x256, TR4.48, TE2.24,
FA90, TSE1, FOV 328). The amplitude of movement of the apex
and dorsal costophrenic angle of the diaphragm were measured
for two test conditions: tidal breathing and voluntary breath
holding. The maximal inferior and superior positions of the
diaphragm were subtracted from the corresponding positions
during voluntary movements while breath holding. The average
amplitude of inferio-superior movement of the diaphragm apex
during tidal breathing was 27.3±10.2 mm (mean ± SD), and
during voluntary movement while breath holding was 32.5±16.2
mm. Movement of the costophrenic angle was 39±17.6 mm
during tidal breathing and 45.5±21.2 mm during voluntary
movement while breath holding. The inferior position of the
diaphragm was lower in 11 of 16 subjects (68.75 %) and
identical in 2 of 16 (12.5 %) subjects during voluntary movement
compared to the breath holding. Pearson’s correlation coefficient
was used to demonstrate that movement of the costophrenic
angle and apex of the diaphragm had a linear relationship in both
examined situations (r=0.876). A correlation was found between
the amplitude of diaphragm movement during tidal breathing and
lung volume (r=0.876). The amplitude of movement of the
diaphragm with or without breathing showed no correlation to
each other (r=0.074). The movement during tidal breathing
shows a correlation with the changes in lung volumes. Dynamic
MRI demonstrated that individuals are capable of moving their
diaphragm voluntarily, but the amplitude of movement differs
from person to person. In this study, the movements of the
diaphragm apex and the costophrenic angle were synchronous
during voluntary movement of the diaphragm while breath
holding. Although the sample is small, this study confirms that
the function of the diaphragm is not only respiratory but also
postural and can be voluntarily controlled.
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