Diagnostic value of bone and Ga-67 imaging in skeletal tuberculosis

Tuberculosis (TB) remains a major cause of skeletal infection in many parts of the world. Bone scintigraphy is an excellent screening test for bone lesions and Ga-67 scintigraphy is a useful tool for detecting inflammatory lesions. This study determined the value of bone and Ga-67 scans in patients with skeletal TB. Tc-99m MDP and Ga-67 whole-body scans were performed in 24 patients with proved skeletal TB. Twenty-six TB lesions were found in these 24 patients, 8 in the spine, 5 in the knee, 5 in the wrist, 4 in the ankle, 2 in the elbow, 1 in the finger, and 1 in the sacroiliac joint. Of the 26 TB lesions, Tc-99m MDP bone imaging detected 24 and Ga-67 scans revealed 23. The sensitivity rates were 92% (24 of 26) and 88.5% (23 of 26) for bone scans and Ga-67 scans, respectively. When the scans were evaluated in combination, the detection sensitivity was 96.1% (25 of 26). Two lesions that the bone scan failed to detect were in the spine. Ga-67 imaging failed to detect two spinal lesions and one lesion in the knee. The detection sensitivities of bone and gallium scans were high for skeletal TB, although neither scan was specific for TB lesions. Either the bone or Ga-67 scan can be used in the clinical setting as a convenient screening test to detect multiple sites of bone involvement in TB, and to indicate the sites for further detailed evaluation by CT, MRI, or biopsy.