Figures 9, 10. (9) Hemiagenesis of the thyroid gland. Axial contrast-enhanced CT scan demonstrates absence of the left lobe, which is a typical finding in hemiagenesis. (10) Pyramidal lobe. Axial contrast-enhanced CT scan shows persistence of the distal portion of the thyroglossal duct. This condition is present in 50% of the population. P = pyramidal lobe.