| window level | The CT number setting in Hounsfield units of the midpoint of the window width, which is the gray scale of the image; a typical window level for imaging the lungs if -500; for the abdomen, 0. (05 Mar 2000) |
|---|---|
| window width | The range of CT numbers (in Hounsfield units) included in the gray scale video display of the CT image, ranging from 1 to 2000 or 3000, depending on the type of machine. See: window level. (05 Mar 2000) |
| soft tissue window | mediastinal window |
| oval window | Fenestra of the vestibule; an oval opening in the medial wall of the middle ear leading into the vestibule. Normally it is covered by the base of the stapes. (12 Dec 1998) |
| tachycardia window | In paroxysmal tachycardia of the reentry type, the interval of time (the window) between the earliest and latest premature activation that can excite the paroxysm. (05 Mar 2000) |
| little fossa of the cochlear window | A depression on the medial wall of the middle ear which has the fenestra cochleae (round window) in its lower portion. Synonym: fossula rotunda, little fossa of the cochlear window. (05 Mar 2000) |
| little fossa of the vestibular window | A depression on the medial wall of the middle ear which has the fenestra vestibulae (oval window) in its lower portion. Synonym: Huguier's sinus, little fossa of the vestibular window, little fossa of the vestibular round window. (05 Mar 2000) |
| lung window | CT settings of window level and width appropriate to showing lung detail; soft tissues are white or nearly so. Mediastinal window, CT settings of window level and width appropriate to showing soft tissue structures; the lungs become black at these settings. Synonym: soft tissue window. (05 Mar 2000) |
| alveolar ventilation | The volume of gas expired from the alveoli to the outside of the body per minute; calculated as the respiratory frequency (f) multiplied by the difference between tidal volume and the dead space (VT -VD); units: ml/min BTPS. (05 Mar 2000) |
| artificial ventilation | Application of mechanically or manually generated pressures, usually positive, to gas(es) in or about the airway as a means of producing gas exchange between the lungs and surrounding atmosphere. Synonym: artificial respiration. (05 Mar 2000) |
| assist-control ventilation | Artificial respiration in which inspiration is produced automatically after a set interval if the person has not already begun to inspire. Compare: assisted ventilation, controlled ventilation. (05 Mar 2000) |
| assisted mechanical ventilation | <anaesthetics> The use of a mechanical device to fill the lungs with oxygenated air then allow time for passive exhalation. (27 Sep 1997) |
| assisted ventilation | Application of mechanically or manually generated positive pressure to gas(es) in or about the airway during inhalation as a means of augmenting movement of gases into the lungs. Synonym: assisted respiration. (05 Mar 2000) |
| manual ventilation | Intermittent manual compression of a gas-filled reservoir bag to force gases into a patient's lungs and thus maintain oxygenation and carbon dioxide elimination during apnea or hypoventilation. (05 Mar 2000) |
| ventilation | 1. In respiratory physiology, the process of exchange of air between the lungs and the ambient air. Pulmonary ventilation (usually measured in litres per minute) refers to the total exchange, whereas alveolar ventilation refers to the effective ventilation of the alveoli, in which gas exchange with the blood takes place. 2. In psychiatry, verbalisation of one's emotional problems. Origin: L. Ventilatio (18 Nov 1997) |