Nurse-Led Gastric Preparation for Gas-Negative-Contrast Volume-Rendered Three-Dimensional Virtual Endoscopy-Like...

To evaluate nurse-led gastric preparation for photon-counting computed tomography (PCCT)-based gas-negative-contrast volume-rendered (gas-VRT) virtual endoscopic gastric imaging, focusing on effervescent powder dose, PCCT-related image-quality advantages, and water-assisted preparation.

This single-center prospective randomized trial enrolled 120 patients undergoing contrast-enhanced abdominal CT. Participants were allocated into four groups (n = 30 each): PCCT-3g, PCCT-6g, energy-integrating detector (EID)-6g, and PCCT-3g+W. All gastric preparations followed standardized nurse training and a nurse-led five-step preparation protocol, including patient instruction, protocol-specific gastric preparation, breath-holding guidance, positioning, and scan-timing control. The primary endpoint was the gas-VRT virtual endoscopy-like imaging quality score. Secondary endpoints included intragastric gas/liquid volume, overall and antral gastric distension, gastric wall layer visibility, quantitative image metrics, patient tolerance, and adverse events.

All patients finished examinations without severe adverse events. PCCT-6g achieved a larger intragastric gas volume than PCCT-3g, with an increase of 201.85 cm³, superior gastric distension and gas-VRT quality (all P < 0.001), accompanied by higher discomfort (numeric rating scale score, 0.63 ± 0.85 vs 0.07 ± 0.25). At an identical 6 g effervescent dose, PCCT and EID-CT yielded comparable distension and gas-VRT images; PCCT provided lower noise (5.37 ± 0.72 HU vs 10.90 ± 1.98 HU) and improved signal-to-noise ratio (SNR) (12.56 ± 1.92 vs 5.08 ± 0.88), contrast-to-noise ratio (CNR) (18.89 ± 4.16 vs 4.97 ± 1.80), and wall layer visualization (all P < 0.001). Water supplementation increased intragastric liquid volume by 279.68 cm³ and antral distension score by 2.13 points in the PCCT-3g group, but failed to enhance gas-VRT quality.

Nurse-led PCCT gastric preparation can be customized for different imaging objectives. Six grams of effervescent powder is preferable for gas-VRT virtual endoscopic imaging, while 3 g may be sufficient for routine gastric evaluation. Under the same 6 g preparation protocol, PCCT provided lower image noise, higher SNR/CNR, and clearer gastric wall layer visualization than EID-CT, suggesting platform-specific value beyond gastric distension alone. Water assistance may benefits antral cross-sectional assessment but did not improve gas-VRT imaging.