Figure 1.

Examples of tuberculosis bronchial spread patterns on PET-CT scans with 3D renderings

Images are of baseline scans unless otherwise noted. (A) Right upper lobe cavity drains down the S2 segment bronchus (blue arrow), across to the S3 segment bronchus (red arrow), and down the right bronchus intermedius (green arrow) to the S4 segment bronchus (yellow arrow), with spread of disease to those segments. The S2 segment lesion is red with a green cavity, S3 segment is yellow, and S4–5 segments are purple. (B) Bronchus (blue arrow) drains left S1–2 segment cavity straight down towards the left main bronchus (green arrow), branching to the S3 segment bronchus (yellow arrow) and down into the lower lobe (red arrow) to cause disease distal to those bronchi. In the 3D rendering, the S1–2 segment is orange with a green cavity, S3 segment is pink, and lower lobe disease is blue. (C) A bronchus (blue arrow) is visualised exiting the right S2 segment cavity, connecting down towards the right main bronchus (green arrow), with the S3 segment bronchus (red arrow) shooting off to cause disease anteriorly. S6 segment bronchus (purple arrow) comes off the right lower lobe bronchus and branches into the S6 segment (purple arrow) leading to disease in the apex of the right lower lobe. S7 bronchus (yellow arrow) and S10 bronchus (black arrow) are clearly outlined, leading to disease in those respective segments. In the 3D rendering, the S2 segment is pink with yellow cavity, the S3 segment is green, and the S6 and S10 segments are orange. (D) At baseline (top row), there are two cavities in the right upper lobe and another in the apical S6 segment of the right lower lobe. One or more of these spread tuberculosis bronchially down the right main bronchus (green arrow) to cause disease in the right lower lobe S7 and S8 segments. The left upper lobe is minimally involved at baseline with new or expanding S3 lesions appearing at week 4 (bottom row). At baseline, the right main bronchus inflammation from the right sided cavities spreads to the carina (green arrow). At week 4, the left main bronchus connects to the left S3 segment bronchi (blue arrows) and leads directly into the new or expanding lesion. The left S3 segment bronchus leading to the lesion was not well visualised at baseline, suggesting they became more inflamed by week 4, possibly from the increased bronchial spread. Bronchial spread across the carina like this could occur in a patient who sleeps on their left side at night. 3D=three-dimensional.