title: Vacuum phenomenon.
abstract: This article describes the theory of the formation of the vacuum phenomenon (VP), the detection of the VP, the different medical causes, the different locations of the presentation of the VP, and the differential diagnoses. In the human body, the cavitation effect is recognized on radiological studies; it is called the VP. The mechanism responsible for the formation of the VP is as follows: if an enclosed tissue space is allowed to expand as a rebound phenomenon after an external impact, the volume within the enclosed space will increase. In the setting of expanding volume, the pressure within the space will decrease. The solubility of the gas in the enclosed space will decrease as the pressure of the space decreases. Decreased solubility allows a gas to leave a solution. Clinically, the pathologies associated with the VP have been reported to mainly include the normal joint motion, degeneration of the intervertebral discs or joints, and trauma. The frequent use of CT for trauma patients and the high spatial resolution of CT images might produce the greatest number of chances to detect the VP in trauma patients. The VP is observed at locations that experience a traumatic impact; thus, an analysis of the VP may be useful for elucidating the mechanism of an injury. When the VP is located in the abdomen, it is important to include perforation of the digestive tract in the differential diagnosis. The presence of the VP in trauma patients does not itself influence the final outcome.
authors.affiliation: Department of Acute Critical Care Medicine, Shizuoka Hospital, Juntendo University, 1129 Nagaoka, 410-2295, Izunokuni, Shizuoka, Japan. yyanaga@juntendo.ac.jp.
authors.forename: Youichi
authors.initials: Y
authors.lastname: Yanagawa
authors.affiliation: Department of Acute Critical Care Medicine, Shizuoka Hospital, Juntendo University, 1129 Nagaoka, 410-2295, Izunokuni, Shizuoka, Japan.
authors.forename: Hiromichi
authors.initials: H
authors.lastname: Ohsaka
authors.affiliation: Department of Acute Critical Care Medicine, Shizuoka Hospital, Juntendo University, 1129 Nagaoka, 410-2295, Izunokuni, Shizuoka, Japan.
authors.forename: Kei
authors.initials: K
authors.lastname: Jitsuiki
authors.affiliation: Department of Acute Critical Care Medicine, Shizuoka Hospital, Juntendo University, 1129 Nagaoka, 410-2295, Izunokuni, Shizuoka, Japan.
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Yoshizawa
authors.affiliation: Department of Acute Critical Care Medicine, Shizuoka Hospital, Juntendo University, 1129 Nagaoka, 410-2295, Izunokuni, Shizuoka, Japan.
authors.forename: Ikuto
authors.initials: I
authors.lastname: Takeuchi
authors.affiliation: Department of Acute Critical Care Medicine, Shizuoka Hospital, Juntendo University, 1129 Nagaoka, 410-2295, Izunokuni, Shizuoka, Japan.
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Omori
authors.affiliation: Department of Acute Critical Care Medicine, Shizuoka Hospital, Juntendo University, 1129 Nagaoka, 410-2295, Izunokuni, Shizuoka, Japan.
authors.forename: Yasumasa
authors.initials: Y
authors.lastname: Oode
authors.affiliation: Department of Acute Critical Care Medicine, Shizuoka Hospital, Juntendo University, 1129 Nagaoka, 410-2295, Izunokuni, Shizuoka, Japan.
authors.forename: Kouhei
authors.initials: K
authors.lastname: Ishikawa
mesh_terms: D003937:Diagnosis, Differential; D005740:Gases; D006801:Humans; D007592:Joint Diseases / Q000000981:diagnostic imaging*; D014057:Tomography, X-Ray Computed; D014618:Vacuum
chemical_list: D005740:Gases
keywords: CT; Degeneration; Free air; Trauma; Vacuum phenomena