Nine Takeaways from New Consensus on Abdominal Photon-Counting CT Protocols in Adults

Offering 20 recommendation on protocol features for the use of photon-counting computed tomography (PCCT) for abdominal imaging in adults, the Society of Abdominal Radiology (SAR) has published new consensus guidelines that cover parameters for PCCT in portal venous CT, multiphase aortic CT and multiphase pancreas CT imaging.

The multi-institutional consensus, recently published in the American Journal of Roentgenology, was based off survey findings and subsequent voting on consensus statements by radiologists from nine facilities.

Here are some key takeaways from the new SAR consensus on abdominal PCCT.

1. For routine portal venous phase CT, the consensus authors noted unanimous support for utilizing the QuantumPlus mode, optimizing virtual monoenergetic imaging (VMI) for soft tissue with contrast and ensuring the archiving of a special spectral image (SSI) to facilitate retrospective spectral post-processing.

2. While the consensus recommendations noted the use of 70 keV for the primary viewing energy level of routine portal venous CT, the authors noted disparities in the voting for primary viewing reconstruction. While four facilities utilized 70 keV VMI, three institutions employed 67 keV and one facility opted for 60 keV VMI, according to the consensus authors.

3. For image reconstruction with routine portal venous CT, the consensus authors recommended a medium sharp kernel (Br44).

4. For multiphase aortic computed tomography angiography (CTA), the researchers emphasized QuantumPlus mode scanning for arterial and venous phases, optimization of VMI selection for vascular imaging, and a venous phase-derived SSI file to enable retrospective spectral processing.

5. While the consensus guidelines recommend a fixed tube potential of 140 kVp for multiphase aortic CTA, the authors noted variability in the voting with two facilities opting for automated selection of tube potential and one institution utilizing 120 kVp.

6. There was considerable variability with the primary reconstruction kernel for multiphase aortic CTA in the initial voting, according to the consensus authors.

7. For multiphase pancreas CT, the consensus authors recommended QuantumPlus mode scanning for pancreatic parenchymal and portal venous phases, optimizing VMI selection for soft tissue with contrast, and archiving of the SSI file from the pancreatic and portal venous phases to facilitate retrospective spectral processing.

8. There was considerable variability with respect to portal venous and pancreatic phase image acquisitions in the initial voting with multiphase pancreatic CT. While four facilities employed 70 keV images for pancreatic phase assessment, the consensus authors acknowledged that other institutions utilized 67 keV, 60 keV and threshold 3D images.

9. For image reconstruction with multiphase pancreatic CT, the consensus authors advocated use of a medium sharp kernel (Br44) and forwarding an additional low-energy reconstruction image from the pancreatic parenchymal phase to PACS.