Dual-energy CT captures subtle pancreatic masses

Faster and better visualization are the main reasons to use dual-energy CT for the assessment of pancreatic masses, according to a presentation at the Stanford International Symposium on Multi-detector Row CT in Las Vegas, Nevada.

Dr. Anno Graser, currently a fellow in the radiology department at New York University Medical Center, outlined the main advantages dual-energy CT provides:

• immediate visualization of tumor mass enhancement;
• visualization of subtle enhancement differences;
• ability to calculate virtual unenhanced images; and
• ability to assess vascular anatomy and involvement.

Graser offered a brief explanation of how each of these elements can help pinpoint early-stage masses. Color coding of the images, for example, draws immediate attention to the areas of mass enhancement. Dual-energy CT clarifies subtle enhancement differences between masses and the normal body of pancreas, based on differences in attenuation. Virtual unenhanced images can be used to quantify enhancement patterns.

Graser also mentioned other advanced visualization options with dual-energy CT.

"You can use these (dual-energy) data sets to create curved planar reformatting and 3D image volume rendering, looking at venous anatomy with greater clarity," he said.

Finally, assessing vascular anatomy and involvement is important when deciding whether a patient is a candidate for surgical resection, he said.

At the University of Munich in Germany, Graser and colleagues have reported successful results with dual-energy CT for characterizing renal and ureteral stones. In a paper published in Investigative Radiology, they scanned 24 renal calculi, using dual-energy properties to differentiate between uric acid and other calculi (2008;43:2:112-119). They used the following scan parameters:

• tube potentials of 80 kVp and 140 kVp;
• tube currents of 342 mAs and 76 mAs; and
• collimation of 14 × 1.2 mm2.

According to their results, uric acid, cystine, struvite, and mixed renal calculi could be differentiated from other types of stones on dual-energy CT scans. This information can guide patients into pharmacological treatment rather than surgery or shockwave therapy, the authors said.

-By Shalmali Pal