Pancreas: optimal scan delay for contrast-enhanced multi-detector row CT

Area of Science:

• Radiology
• Medical Imaging
• Gastrointestinal Imaging

Background:

• Multiphasic contrast-enhanced computed tomography (CT) is crucial for pancreatic imaging.
• Determining optimal scan delays is essential for maximizing diagnostic accuracy.

Purpose of the Study:

• To prospectively establish the ideal scan delays for multiphasic contrast medium-enhanced imaging of the pancreas using multi-detector row CT.
• To correlate quantitative enhancement measurements with qualitative assessments.

Main Methods:

• 191 patients underwent three-phase pancreatic CT with a fixed 30-second intravenous contrast injection.
• Patients were prospectively assigned to four groups with varying scan delays (25-65, 30-70, 35-75, 40-80 seconds).
• Quantitative CT numbers and qualitative enhancement scales were used to assess imaging quality.

Main Results:

• Peak enhancement for the abdominal aorta and superior mesenteric artery occurred at approximately 35 seconds.
• Pancreatic parenchyma showed maximal enhancement between 35-45 seconds, peaking at 40 seconds.
• Liver parenchyma enhancement peaked at 60 seconds (55-65 seconds range), while splenic and superior mesenteric veins peaked at 45 and 55 seconds, respectively.

Conclusions:

• Optimal scan delays for pancreatic CT, using the study's injection protocol, are 30-35 seconds for the aorta/SMA, 35-45 seconds for the pancreas, 45 seconds for the splenic vein, and 55+ seconds for the liver.
• These findings provide a standardized protocol for enhanced pancreatic imaging.
• Quantitative and qualitative assessments showed good agreement, validating the proposed timing parameters.