An Tang MD, Presenter: Nothing to Disclose

Jean Sebastien Billiard MD, Abstract Co-Author: Nothing to Disclose

David Olivier Chagnon MD, Abstract Co-Author: Nothing to Disclose

Damien Olivié, Abstract Co-Author: Nothing to Disclose

Jessica Murphy-Lavallée, Abstract Co-Author: Nothing to Disclose

Pascale Audet MD, Abstract Co-Author: Nothing to Disclose

Assia Belblidia MD, Abstract Co-Author: Nothing to Disclose

Fadi Rizk MD, Abstract Co-Author: Nothing to Disclose

Luigi Lepanto MD, Abstract Co-Author: Research grant, Bracco Group

To prospectively assess the optimal pancreatic phase delay in terms of normal pancreas enhancement and tumor-to-pancreas contrast with multidetector computed tomography (CT) by using individualized bolus tracking technique and varying the time delay.

Informed consent was obtained in 46 patients (18 women, 28 men; mean age, 61.5 ± 10.8 years); the institutional review board approved this protocol. Patients were referred for CT because they were suspected of having a pancreatic tumor. CT scanning was performed with a 64-row MDCT for preoperative evaluation. Patients were randomized to an injection delay of 10 sec (n=12), 20 sec (n=18) or 30 sec (n=16) of nonionic contrast material (370 mg of iodine per milliliter) after aortic enhancement above 150 HU at a flow rate of 4 ml/sec. The volume of contrast was adapted to patient weight. Contrast enhancement of pancreas and tumors was measured with circular regions of interest. Statistical analysis included ANOVA and Bonferroni correction post hoc t tests.

The standard of reference (surgery, n= 14; biopsy, n=11; clinical evolution, n= 21) revealed 11 adenocarcinomas, 5 mucinous cystadenoma, 3 serous cystadenoma, 2 intraductal papillary mucinous tumor, 3 pseudocysts, 2 neuroendocrine tumors and 2 ampullomas. Lesion size was 3.5 ± 2.5 cm, ranging from 1.0 to 11.5 cm. Lesions were located in the head (46%), isthmus (22%), body (11%), uncinate (9%) and tail (9%). Pancreatic parenchymal enhancement was higher with an injection delay of 30 sec than with delays of 20 sec and 10 sec, but did not reach statistical significance (mean ± standard deviation, 111.3 ± 38.6 HU vs 101.8 ± 41.0 HU vs 80.3 ± 30.3 HU respectively, P = 0.11). Tumor-to-pancreas contrast with an injection delay of 30 sec was significantly superior to an injection delay of 20 sec for adenocarcinomas (mean ± standard deviation, 52.6 ± 16.0 HU vs 28.3 ± 12.8 HU, P = 0.04).

With a flow rate of 4 ml/sec and weight-adjusted contrast volume, an individualized scan delay of 30 seconds after aortic transit time revealed higher tumor-to-pancreas enhancement for adenocarcinomas than a delay of 20 seconds.

The use of a 30 seconds scan delay after aortic enhancement with weight-adjusted contrast volume improves the attenuation of tumor-to-pancreas contrast.

Tang, A, Billiard, J, Chagnon, D, Olivié, D, Murphy-Lavallée, J, Audet, P, Belblidia, A, Rizk, F, Lepanto, L, Acquisition Time Optimization in Pancreatic Phase with 64-Row Pancreatic MDCT: Preliminary Results.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11013612.html