Chest CT combined with artificial pneumothorax: value in determining origin and extent of tumor

Our plain-English summary of Chest CT combined with artificial pneumothorax: value in determining origin and extent of tumor, by A. Watanabe, K. Shimokata, H. Saka, et al (AJR. American Journal of Roentgenology, 1991).

The study

• Authors: A. Watanabe, K. Shimokata, H. Saka, F. Nomura, S. Sakai
• Journal: AJR. American Journal of Roentgenology
• Published: 1991;156(4):707-10
• Cited by: 24 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

To determine the presence of chest wall and mediastinal invasion by lung cancer and to establish the origin of chest tumors, we studied 12 patients with intrathoracic tumors by using chest CT combined with artificial pneumothorax. Six patients had primary lung cancer, two had metastases, and one each had neurofibroma, pericardial cyst, chondroma of the rib, and malignant mesothelioma. All 12 tumors abutted the chest wall or mediastinum and could not be separated by conventional CT. Between 400 and 800 ml of air was injected into the pleural space before a second CT scan was obtained. No invasion was found at surgery in cancers that were separated from chest wall or mediastinum on CT scans. Surgery revealed chest wall invasion in three patients in whom the CT scans showed that the tumor was not separated from the chest wall. Only one patient with a tumor that was not separated from the mediastinum on CT did not have mediastinal invasion: in this case, only adhesions were found at surgery. Thus, in the eight patients with primary lung cancer and metastasis, sensitivity, specificity, and accuracy were 100%, 80%, and 88%, respectively. In four patients with mediastinal or pleural tumor, CT combined with pneumothorax was useful for establishing the origin of tumors. In all, 11 of the 12 patients were correctly evaluated by using this method. No complications occurred, except for mild chest discomfort in one patient. This study suggests that chest CT combined with artificial pneumothorax is useful for the evaluation of the extension of lung cancer into the chest wall and mediastinum and for the diagnosis of the site of origin of intrathoracic tumors.

In plain English

This study by doctors in Nagoya, Japan, tested a chest imaging technique. It was not a study of asbestos exposure. Between July 1987 and September 1989, 12 patients (five men, seven women, aged 35 to 80) had tumors inside the chest that touched the chest wall or the mediastinum (the central chest area) and could not be separated from them on ordinary CT scans. The doctors injected 400 to 800 ml of air into the space around the lung (an artificial pneumothorax) and scanned again. One patient had malignant mesothelioma; the article gives no information about asbestos. In the eight patients with lung cancer or cancer spread to the lung, sensitivity, specificity and accuracy for detecting invasion were 100%, 80% and 88%. In the mesothelioma patient, most nodules were seen attached to the mediastinum or the visceral pleura. Overall, 11 of 12 patients were satisfactorily examined, and one patient had chest discomfort. The authors concluded the method is useful. They stated it cannot be used with severe pleural adhesion or impaired lung function.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Small clinical case series evaluating a diagnostic imaging technique (CT scanning after artificial pneumothorax), checked against surgical findings
• Who was studied: 12 patients (five men, seven women, aged 35 to 80) with tumors inside the chest, studied from July 1987 to September 1989; authors were based in Nagoya, Japan. Six had primary lung cancer, two had lung metastasis of colonic cancer, and one each had neurofibroma, pericardial cyst, chondroma of the rib, and malignant mesothelioma. All tumors abutted the chest wall or mediastinum and could not be separated on conventional CT.
• Exposure: No asbestos or fiber exposure was studied. The procedure studied was injection of 400 to 800 ml of air into the pleural space before a second CT scan.
• Main results:
  • Of the six lung cancer patients, three had tumors that stayed in contact with the chest wall on the CT scan after pneumothorax, and all three had chest wall invasion at surgery.
  • In the other three lung cancer patients, the tumors were separated from the chest wall or aorta on the scan, and no invasion was found at surgery.
  • In one of the two patients with lung metastasis, the tumor was not separated from the spine on the scan, but surgery found severe pleural adhesion rather than invasion. The authors said the method was not useful in this case.
  • In the eight patients with lung cancer or pulmonary metastasis, sensitivity, specificity, and accuracy for determining chest wall or mediastinal invasion were 100%, 80%, and 88%. The scanned text reads '1 00%'; the article's own abstract confirms 100%.
  • In the patient with malignant mesothelioma, the scans after pneumothorax showed most nodules attached to the mediastinum or the visceral pleura. The authors said this helped determine the origin of the tumors.
  • Overall, 11 of the 12 patients were satisfactorily examined. The scanned text reads '1 1'; the article's own abstract confirms 11.
  • One patient had chest discomfort, which was relieved by removing the air; no chest tube drainage was needed.
• The authors' conclusion: The authors concluded that chest CT combined with artificial pneumothorax is useful for evaluating the extent of lung cancer, clarifies the exact site of diseases inside the chest, and can be applied without troublesome complications.
• Limitations the authors state:
  • The procedure cannot be used in patients with severe pleural adhesion or impaired pulmonary function.
  • The study had one false-positive result.
  • The authors stated that further study including more patients should be done.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Lung cancer.

Medical terms in this study, explained in our Lexicon: Pneumothorax, Lung Cancer, Intrathoracic, Pericardial, Malignant Mesothelioma, Mediastinum, CT Scan, Metastasis.

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