Abdomen and Oncology

Discussion

66-year-old male, focal bladder lesion encountered during prostate ultrasonography. Evaluation with dual-energy CT.

Better demonstration of the bladder wall thickening at lower keV monoenergetic images, quantification of iodine uptake by iodine density and Z effective images.

Axial images

Conventional CT with contrast showed focal thickening of the posterior and left lateral bladder wall. The HU values were similar at affected posterior site (46.8 HU) and unaffected anterior site (44.4 HU) of the bladder wall. Virtual monoenergetic images at 45 keV better demonstrated increased iodine uptake in the thickened bladder wall. Iodine density and Z effective images showed iodine uptake quantitatively at affected and unaffected sites. Transurethral resection was performed, and histology results revealed papillary urothelial carcinoma.

Virtual monoenergetic images at lower keV provide increased conspicuity of thickened bladder wall with increased iodine uptake. Iodine density and Z effective images could also quantitatively demonstrate the increased iodine uptake in the lesion compared to unaffected parts of the bladder wall.

Conventional CT with contrast, axial image at 120 kVp: posterior-left lateral bladder wall thickening. The HU values are similar at affected posterior-left lateral wall (46.8 HU, blue arrow) and unaffected anterior wall (44.4 HU, white arrow).

Virtual monoenergetic axial image at 45 keV: better demonstration of bladder wall thickening (arrow).

Iodine density axial image: increased iodine uptake (1.29 mg/ml) of thickened posterior bladder wall (blue arrow) compared to unaffected anterior site (0.12 mg/ml, white arrow).

Z effective axial image: posterior bladder wall with increased iodine content is color coded in green-blue and has higher effective atomic number (8.05, blue arrow) compared to unaffected anterior bladder wall (7.34) that is color coded in yellow (white arrow).

Papillary lesion with diffuse hyperplasia of urothelium, without infiltration of lamina propria (HE x5).

Urothelium showing architectural disturbance with high atypia (HE x10).

History

Benefits or pitfalls of dual-energy CT

Key images

Findings