Impact of FDG PET on the management of TBC treatment. A pilot study

The aim of this study is to assess the potential impact of double-phase FDG PET versus routine staging in HIV-negative patients suffering from tuberculosis.

16 consecutive patients suffering from tuberculosis underwent contrast-enhanced CT and double-phase FDG PET imaging (45 min, 120 min). Early (E) and delayed (D) SUVmax values were determined for all identified lesions and % change in SUV calculated (DeltaSUV).

Seven patients presented with lung lesions on PET as well as CT (mean SUVmaxE 8.2, mean SUVmaxD 11.1, (p = 0.002), DeltaSUV 35%. In two patients, lesions were judged as non-active on CT. In nine patients, 18 sites of LN involvement were identified on both early and delayed FDG PET images (mean SUVmaxE 6.3, mean SUVmaxD 7.9, (p = 0.0001), DeltaSUV: 25%). 9 out of 18 sites of LN involvement, occurring in five patients, were missed on CT. In four of these five patients, sites of LN involvement were the only sites of extra-pulmonary involvement identified. In 6 out of 16 patients, pleural involvement was identified, respectively in 5 on FDG PET and in 6 on CT imaging (mean SUVmaxE 1.3, mean SUVmaxD 1.7, (p = 0.06), DeltaSUV 21%). In 4 patients, osseous involvement was identified by both FDG PET and CT (mean SUVmaxE 7.2, mean SUVmaxD 10.7, (p = 0,06), DeltaSUV 45%). Finally, in 3 patients, joint involvement was identified on both FDG PET as well as on CT imaging (mean SUVmaxE 4.7, mean SUVmaxD 5.2, DeltaSUV 23%). FDG PET did not identify CT-additional sites of involvement that would have resulted in a prolonged treatment.

In HIV-negative patients suffering from tuberculosis, FDG PET images suggested a more extensive involvement by Mycobacterium tuberculosis when compared to contrast enhanced CT.