Single-energy low-voltage arterial phase MDCT scanning increases conspicuity of adenocarcinoma of the pancreas

PurposeTo test a single-energy low-voltage CT protocol for pancreatic adenocarcinoma.Methods and materialsA total of 30 patients with pathology-proven pancreatic adenocarcinoma underwent 64-row MDCT with arterial phase at 80 kV and were compared to a similar group of 30 patients scanned with a 120 kV protocol. Scans were compared for quantitative image parameters (attenuation and standard deviation in the pancreas, tumor, aorta), CTDI and DLP using an unpaired t-test. Image noise values for each protocol (SD of the psoas) were compared using an unpaired t-test. Effective dose was calculated for each protocol. CNR (=conspicuity/SDnoise) and FOM (CNR2/ED) were calculated. The Catphan600 phantom was used to evaluate image non-uniformity, noise, spatial resolution, and low contrast detectability.ResultsMean patient weight was 68 kg in the study group and 73 kg in the control group (p = 0.0355), while patient diameters at the celiac axis were not significantly different. Mean attenuation was significantly higher at 80 kV in the aorta (517.5 ± 116.4 vs 290.3 ± 76.4 HU) and normal pancreas (154.0 ± 39.95 vs 90.02 ± 19.01 HU) (all p < 0.0001), while no significant difference was observed for adenocarcinoma (61.43 ± 35.61 vs 47.45 ± 18.95; p = n.s.). CTDI and DLP were significantly lower at 80 kV (6.00 ± 0.90 mGy vs 10.24 ± 2.93 mGy, and 180.4 ± 35.49 mGy cm vs 383.8 ± 117 mGy cm, respectively; all p < 0.0001). Tumor conspicuity (HUpancreas − HUtumor) was significantly higher at 80 kV (94.2 ± 39.3 vs 39.5 ± 22 HU; p < 0.0001). Mean image noise was significantly higher at 80 kV (28.32 ± 10.06 vs 19.7 ± 7.1 HU; p < 0.0001). Effective dose was significantly lower at 80 kV (1.984 ± 0.39 vs 5.75 ± 1.75 mSv; p < 0.0001). The total DLP for the exam was 1024 ± 31.86 mGy cm for the 80 kV protocol and 1357 ± 62.60 mGy cm for the 120 kV protocol (p < 0.0001).Phantoms showed higher non-uniformity, slightly higher noise, slightly lower MTF (50%) and slightly higher percentage contrast for the 80 kV protocol.ConclusionSingle-source 80 kV pancreatic phase scanning results in higher conspicuity of pancreatic adenocarcinoma and FOM and in significant dose reduction while maintaining acceptable image quality.