title: A method to detect occult pneumothorax with chest radiography.
abstract: Small pneumothoraces are often not visible on supine screening chest radiographs because they develop anteriorly to the lung. These pneumothoraces are termed occult. Occult pneumothoraces account for an astonishingly high 52% to 63% of all traumatic pneumothoraces. A 19-year-old obese woman was involved in a head-on car accident. The admission anteroposterior chest radiographs were unremarkable. Because of the presence of right chest tenderness and an abrasion, we suspected the presence of a pneumothorax. Thus, we decided to take a supine oblique chest radiograph of the right side of the thorax, which clearly revealed a visceral pleural line, consistent with a diagnosis of traumatic pneumothorax. A pneumothorax may be present when a supine chest radiograph reveals either an apparent deepening of the costophrenic angle (the "deep sulcus sign") or the presence of 2 diaphragm-lung interfaces (the "double diaphragm sign"). However, in practice, supine chest radiographs have poor sensitivity for occult pneumothoraces. Oblique chest radiograph is a useful and fast screening tool that should be considered for cases of blunt chest trauma, especially when transport of critically ill patients to the computed tomographic suite is dangerous or when imminent transfer to another hospital is being arranged and early diagnosis of an occult pneumothorax is essential.
authors.affiliation: Department of Trauma and Emergency Surgery, Saiseikai Yokohamashi Tobu Hospital, 3-6-1 Shimosueyoshi, Yokohama, Kanagawa, Japan. m-shokei@feel.ocn.ne.jp
authors.forename: Shokei
authors.initials: S
authors.lastname: Matsumoto
authors.forename: Masanobu
authors.initials: M
authors.lastname: Kishikawa
authors.forename: Koichi
authors.initials: K
authors.lastname: Hayakawa
authors.forename: Atsushi
authors.initials: A
authors.lastname: Narumi
authors.forename: Katsutoshi
authors.initials: K
authors.lastname: Matsunami
authors.forename: Mitsuhide
authors.initials: M
authors.lastname: Kitano
mesh_terms: D005260:Female; D006801:Humans; D011030:Pneumothorax / Q000000981:diagnostic imaging* / Q000209:etiology; D011187:Posture; D013902:Radiography, Thoracic / Q000379:methods*; D014949:Wounds, Nonpenetrating / Q000150:complications / Q000000981:diagnostic imaging; D055815:Young Adult