Fig. 5: [¹⁸F]FDT Scans of an Mtb-infected Marmoset Correlate with 4-week HRZE Treatment.

A–G 3D volume renderings and 2D axial and sagittal images and quantification of FDG uptake in Mtb-infected marmoset and the same marmoset given [¹⁸F]FDT scans with the number of days post infection (DPI) indicated above. A–C) In the pretreatment scan with [¹⁸F]FDG PET (0.7 mCi) collected 60 min post-injection, cyan arrrows point to 5 lesions. D–E Marmoset imaged with [¹⁸F]FDG after 4 weeks of treatment showing the same 5 lesions. F [¹⁸F]FDG SUV before and after treatment of the lung lesions was variable and sometimes increased with treatment (p = 0.011, two-tailed paired T test, n = 9 lesions). G Total probe uptake as determined by total glycolytic activity (TGA) of the lesions showed a lesion-dependent pattern suggestive of avid [¹⁸F]FDG uptake, despite HRZE treatment (p = 0.239, two-tailed paired T test). H–N By contrast, similarly-timed (pretreatment and 4 weeks of treatment) [¹⁸F]FDT scans 90 min post injection (I 0.7 mCi; K 1 mCi) showed reduced SUV and total [¹⁸F]FDT uptake in the lesions after 4 weeks of treatment. Typical initial lesion bacterial load is 4 to 6 log CFU. Lower bacterial load was indeed observed in the lesions: lesion 1 = 2.3, lesion 2 = 2.6, lesion 3 = 3.1, lesion 4 = 0.9 log CFU and CFU is associated with FDT total uptake. M After HRZE combination drug therapy, the [¹⁸F]FDT SUV/CMR of the lung lesions was significantly decreased (p = 0.0069, two-tailed paired T test, n = 9 lesions) and N the total [¹⁸F]FDT uptake in the lesions, as determined by TGA, was also reduced (p = 0.0036, two-tailed paired T test). One representative image pair is shown of three similar treatment experiments. Please also see Source Data File.