Ann Thorac Surg 1999;67:847-849
© 1999 The Society of Thoracic Surgeons
Case Reports
Helical computed tomographic minimum-intensity projection of a slit in an airway obstruction
Shunsuke Endo, MDa,
Fumio Murayama, MDa,
Tsuyoshi Hasegawa, MDa,
Yasunori Sohara, MDa,
Katsuo Fuse, MDa
a Department of Thoracic Surgery, Jichi Medical School, Tochigi, Japan
Accepted for publication September 2, 1998.
Address reprint requests to Dr Endo, Dept. of Thoracic Surgery, Jichi Medical School, 3311-1 Yakushiji, Minamikawachi-machi, Kawachi-gun, Tochigi 329-0498 Japan
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Abstract
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We treated a 54-year-old man with an anastomotic obstruction after a right upper sleeve lobectomy. By using minimum intensity projection images that were generated from helical computed tomographic data sets that indicated a twisted slit enhanced with air a few millimeters in length, through anastomosis to the distal bronchus, we successfully treated the obstruction by bronchoscopic balloon dilatation.
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Introduction
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Bronchoscopic procedures for anastomotic stenosis or obstruction after airway reconstruction may prevent a second anastomosis or completion pneumonectomy. However, existing examination techniques, such as bronchography, conventional computed tomography, and bronchoscopy, are not always able to visualize enough accurate anastomotic structures to determine further procedures. In the present case, we used helical computed tomographic minimum-intensity projection, which led us to a successful bronchoscopic balloon dilation.
A 54-year-old man had a right sleeve upper lobectomy and mediastinal dissection for a mucoepidermoid carcinoma originating in the right upper bronchus and invading the main bronchus. The telescopic anastomotic procedure was done with interrupted sutures of monofilament absorbable thread, and the bronchial anastomosis was wrapped with an intercostal pedicle flap to prevent anastomotic dehiscence. Pathologic examination showed no cancerous tissue in the surgical stump or any dissected lymph nodes. Bronchoscopy on the seventh postoperative day showed that the anastomotic area was severely ischemic. Granulation was found in the area at follow-up bronchoscopy, but the patient was discharged uneventfully on the 51st postoperative day. He was readmitted to our hospital on the 74th postoperative day with complaints of progressive dyspnea. Chest radiograph and bronchoscopy at this second admission showed atelectasis in the residual right lung (Fig 1) and obstructive anastomosis. A helical computed tomographic scan was obtained with a width of 3.0 mm, a table pitch of 3.0, and a reconstruction pitch of 1.5. Helical computed tomographic minimum-intensity projections were generated with the Magic View workstation (Siemens, Erlanger, Germany) by projecting imaginary rays through the three-dimensional anastomotic structure of interpolated image data and mapping the minimum attenuation value of air along each ray to a gray scale. It showed a normal intermediate bronchus beyond a twisted air slit a few millimeters in length (Fig 2). Using a bronchoscope, passed a guide wire carefully through the obstructive anastomosis. Bronchoscopic dilation using a balloon catheter, the outer diameter of which was 8 to 10 mm (Boston Science Corp, Watertown, MA), was performed three times for 5 minutes with the luminal inflation pressure of 4 atm. The residual lung proved to be reexpanded by chest radiography after endoscopic balloon dilations, and the lumen of the anastomosis was dilated to 7 x 8 mm (Fig 2D). The patient was discharged for the second time on the 120th postoperative day after the upper sleeve lobectomy.
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Fig 1. Chest roentgenogram at the second hospitalization, showing the atelectasis of the right residual lung after sleeve upper lobectomy.
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Fig 2. Integrated helical computed tomographic minimum-intensity projection focused on the anastomosis. (A) Coronal view obtained with level of -499H and width of 1,688H. (B) Transverse view with the level of -9H and width of 936H. (C) Transverse view with level of -490H and width of 1,832H, assessing an air slit to the normal distal bronchus within the anastomosis. Helical computed tomographic minimum-intensity projection after endoscopic balloon dilation for the anastomotic obstruction showing marked resolution of anastomotic obstruction. (D) Coronal view obtained with level of -512H and width of >1,688H.
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Comment
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Endoscopic balloon dilation is temporarily effective for anastomotic stenosis, and it sometimes requires further stent insertion [1]. Balloon dilation can be successful if the obstruction is short, the anastomosis is stable, and there is a clear view of the spatial orientation and stability of the distal bronchus. Fortunately, the anastomotic stenosis was sufficiently short and fixed because of the pedicle wrap.
The treatment of anastomotic stenosis or obstruction requires knowledge of the involved structures as to the degree of patency, length, and the spatial orientation of the distal airway. Those measurements cannot be estimated by conventional examinations, including bronchoscopy, in cases of severe stenosis or obstruction, as in the present case. The workstation can reconstruct minimum and maximum intensity projection images, surface shading display images, or multiplanar reconstruction images, according to the purpose, from the helical computed tomographic data sets. The minimum-intensity projection images can create an image of the peripheral airway by enhancing luminal air [2]. Furthermore, images with the anastomotic structure, even though it is twisted, can be reconstructed three dimensionally [3]. In the present case, because a slight path was clearly detected with the helical computed tomographic minimum-intensity projections, unlike the chest radiography and bronchoscopy, we were optimistic about performing endoscopic balloon dilation for the anastomotic obstruction. The physician must cooperate with the radiologist as well as the technologist, to explain the clinical data, the purpose of the examination, and the region of interest [4]. The images reconstructed in this manner can provide more reliable information regarding the anastomotic airway structure.
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Acknowledgments
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We thank Mr Takakusagi, a chief technician in the Department of Radiology, for technical assistance.
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References
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Kauczor H.U., Wolcke B., Fischer B., Mildenberger P., Lorenz J., Thelen M. Three-dimensional helical CT of the tracheobronchial tree: evaluation of imaging protocols and assessment of suspected stenoses with bronchoscopic correlation. Am J Roentgenol 1996;167:419-424.[Abstract/Free Full Text]
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Abstract
Introduction
