Tuberc Respir Dis.  2007 Jun;62(6):479-485.

Differences in CT Findings According to Sputum Smear Results in Patients with Active Pulmonary Tuberculosis Having a Single Cavity

• Song IS
• Lee HY
• Yoo SM

Abstract

Background
The purpose of this study was to evaluate the differences in CT findings according to sputum smear- positive or -negative results in patients with active pulmonary tuberculosis having a single cavity. Methods: A total of 32 patients with active pulmonary tuberculosis having a single cavity on CT were classified into two groups: smear-positive (n=19) and smear-negative (n=13). The CT findings were reviewed retrospectively. The presence of consolidation, the number of lobes showing consolidation, ground-glass opacity, micronodules and nodule, the maximum diameter of the cavity, and the shape and maximum thickness of the cavity wall were assessed. Result: The maximum diameter of the cavity was 33.84 +/- 13.65 mm and 27.08 +/- 9.04 mm in the smear-positive and -negative groups, respectively (p>0.05). The amount of consolidation and the number of lobes with consolidation were found to be 89.5% and 30.8% (p=0.01) and 1.37 +/- 0.90 and 0.31 +/- 0.48 (p=0.0002) in the smear-positive and -negative groups, respectively. Consolidations in two or more lobes were only noted in 31.6% of in the sputum smear- positive group (p< 0.05). There were no other significant differences between the two groups. The sensitivity, specificity, positive and negative predictive values for the presence of consolidation were 89.5%, 69.2%, 73.9%, and 81.8%, respectively. Conclusion: While the absence of consolidation on CT may be associated with sputum smear-negative results in patients with active pulmonary tuberculosis having a single cavity, the presence of consolidation in two or more lobes on CT may be associated with spear-positive results in these patients.

Keyword

Computed tomography; Sputum smear; Pulmonary tuberculosis

MeSH Terms

Humans
Retrospective Studies
Sputum*
Tuberculosis, Pulmonary*

Figure

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  Figure 1 CT images of a 30-year-old woman among the sputum smear-positive group in whom CT scan shows a cavity and consolidation. (A) CT scan at the level of both lower lobes bronchi shows a thin-walled cavity (52 × 43 mm in diameter) (arrowheads) in left lower lobe. Multiple centrilobular micronodules (arrows) are also demonstrated in the left lower lobe. (B) CT scan at the level of diaphragm shows a patch consolidation in left lower lobe (arrows).

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  Figure 2 A CT image of a 29-year-old man among the sputum smear-negative group in whom CT scan shows a cavity and no consolidation. CT scan at the level of bronchus intermedius shows a cavity (21 × 17 mm in diameter)(arrowheads) in right lower lobe. Multiple centrilobular micronodules (arrows) are also demonstrated in the right lower lobe. However, consolidations were not noted in this case through the entire CT images.

Reference

1. Canetti G. Present aspects of bacterial resistance in tuberculosis. Am Rev Respir Dis. 1965. 92:687–703.

2. Kosaka N, Sakai T, Uematsu H, Kimura H, Hase M, Noguchi M, et al. Specific high-resolution computed tomography findings associated with sputum smear-positive pulmonary tuberculosis. J Comput Assist Tomogr. 2005. 29:801–804.

3. Shaw JB, Wynn-Williams N. Infectivity of pulmonary tuberculosis in relation to sputum status. Am Rev Tuberc. 1954. 69:724–732.

4. Liippo KK, Kulmala K, Tala EO. Focusing tuberculosis contact tracing by smear grading of index cases. Am Rev Respir Dis. 1993. 148:235–236.

5. Grzybowski S, Barnett GD, Styblo K. Contacts of cases of active pulmonary tuberculosis. Bull Int Union Tuberc. 1975. 50:90–106.

6. Van Geuns HA, Meijer J, Styblo K. Results of contact examination in Rotterdam, 1967-1969. Bull Int Union Tuberc. 1975. 50:107–121.

7. Telzak EE, Fazal BA, Pollard CL, Turett GS, Justman JE, Blum S. Factors influencing time to sputum conversion among patients with smear- positive pulmonary tuberculosis. Clin Infect Dis. 1997. 25:666–670.

8. American Thoracic Society. Diagnostic standards and classification of tuberculosis in adults and children. Am J Respir Crit Care Med. 2000. 161:1376–1395.

9. Matsuoka S, Uchiyama K, Shima H, Suzuki K, Shimura A, Sasaki Y, et al. Relationship between CT findings of pulmonary tuberculosis and the number of acid-fast bacilli on sputum smears. Clin Imaging. 2004. 28:119–123.

10. Na MJ. Comparison of induced sputum and bronchoscopy in diagnosis of active pulmonary tuberculosis. Korean J Med. 1998. 55:75–82.

11. Baek SH, Lee JB, Kang MJ, Son JW, Lee SJ, Kim DG, et al. How reliable is sputum PCR test in the diagnosis of pulmonary tuberculosis when sputum smear is negative? Tuberc Respir Dis. 2001. 50:222–228.

12. Mo EK, Kyung TY, Kim DG, Park MJ, Lee MG, Hyun IG, et al. The clinical utility of polymerase chain reaction in the bronchoalveolar lavage fluid for the detection of mycobacteria. Tuberc Respir Dis. 1998. 46:519–528.