Role of Gene Xpert MTB/RIF assay for detecting tuberculous spondylitis in specimens obtained by CT-guided aspiration/biopsy and spectrum of imaging findings in spinal tuberculosis

Abstract

Objective

To evaluate the utility of the GeneXpert MTB/RIF assay for the diagnosis of tuberculous spondylitis in samples obtained by CT-guided aspiration/biopsy. The effect of anti-tubercular treatment, specimen type, and imaging findings on laboratory results was also assessed along with a comparison of imaging findings in tubercular versus non-tubercular cases.

Methods

This prospective observational study, planned for CT-guided aspiration/ biopsy, included 70 adults with suspected tuberculous spondylitis. Specimens were sent for microscopy, histopathology, TB culture, and Gene Xpert MTB/RIF assay. The correlation of sampling location, specimen type, anti-tubercular treatment, and imaging findings on microbiology results was documented.

Results

A definite diagnosis of tuberculous spondylitis was obtained in 50 cases. The assay had a 100 % agreement for smear-positive, culture-positive, specimens while the overall agreement was 41.3 %. Rifampicin resistance was detected in 8 cases. Seventy-one percent of patients were on empiric ATT. Imaging findings such as end plate destruction, paravertebral soft tissue thickening and abscess, disc involvement, sequestrum, and bony fragments were significantly associated with a final diagnosis of spinal tuberculosis.

Conclusions

The Gene Xpert MTB/RIF assay performed on specimens obtained by CT-guided aspiration/biopsy is a sensitive and rapid method of establishing a diagnosis of tuberculous spondylitis even in cases on ATT.