Se Young Ko, Abstract Co-Author: Nothing to Disclose

Myung Hee Chung MD, PhD, Presenter: Nothing to Disclose

Yeon Soo Lim MD, Abstract Co-Author: Nothing to Disclose

Hyung Wook Lim, Abstract Co-Author: Nothing to Disclose

Na-Young Jung MD, Abstract Co-Author: Nothing to Disclose

Joon-Young Ohm, Abstract Co-Author: Nothing to Disclose

Bae Young Lee, Abstract Co-Author: Nothing to Disclose

Park Seog Hee, Abstract Co-Author: Nothing to Disclose

Jimin Kahng, Abstract Co-Author: Nothing to Disclose

To compare CT findings for differentiating tuberculosis from pneumonia in radiologically difficult cases

We retrospectively analyzed fifty patients with tuberculosis (29 male, 21 female, aged 23 - 82 years, mean 53.3) and thirty nine patients with pneumonia (25 male, 14 female, aged 15 -89 years, mean 52.6), who underwent enhanced chest CT examinations between January 2006 to December 2009. Two chest radiologists retrospectively interpreted the CT images for parenchymal abnormalities, enlarged lymph nodes, pleural effusions, and central bronchial narrowing. The density of ROI was measured in consolidation on enhanced CT and net enhancement (E) was calculated in both of them. Diagnostic methods included culture, AFB stain, and PCR of sputum, transbronchial aspirates and biopsy; and clinical outcome after treatment.

The frequency of centrilobular nodules, nodule (about 1.0 cm), cavity, conglomerated nodules, and enlarged lymph nodes were significantly higher in patients with tuberculosis than those with pneumonia (p<0.001, p<0.000, p<0.005, p<0.000, p<0.05). The centrilobular nodules were larger and denser in patients with tuberculosis  than with pneumonia (p<0.002). There were no significant differences in frequency of “tree-in-bud”, pleural effusion, bronchial narrowing, multiplicity, and predilection sites of nodules or consolidations between the two groups. According to consolidation, volume decrease and internal bronchial beaded appearance (alternately irregular narrowing and dilatation) tended to be more frequent in patients with tuberculosis (p<0.05, p<0.000). The tuberculous consolidations were significantly less enhanced (cut off value: 64.5 HU, sensitivity: 69.2 %, specificity: 58.4 %) and net E measurement was more valuable (cut off: 30 HU, sensitivity: 74.4 %, specificity: 63.7 %). Diagnostic accuracy by evaluating overall CT findings was 82%; sensitivity, 82%; specificity, 82.1%; positive predictive value, 85.4%; negative predictive value, 78.1%).

Less enhanced consolidation with volume decrease and internal irregular beaded bronchial shape, and somewhat denser and larger centrilobular nodules are helpful CT findings in addition to well known CT findings including cavities and granulomatous nodules in patients with tuberculosis.

The tuberculosis occasionally can not easily be differentiated from bacterial pneumonia on clinical and radiological grounds.

Ko, S, Chung, M, Lim, Y, Lim, H, Jung, N, Ohm, J, Lee, B, Seog Hee, P, Kahng, J, Tuberculosis versus Pneumonia: Enhancement Pattern and Bronchial Shape in Consolidation as Differential Points on MDCT.  Radiological Society of North America 2010 Scientific Assembly and Annual Meeting, November 28 - December 3, 2010 ,Chicago IL. http://archive.rsna.org/2010/9009841.html