Single-energy low-voltage arterial phase MDCT scanning increases conspicuity of adenocarcinoma of the pancreas.
OBJECTIVE
To test a single-energy low-voltage CT protocol for pancreatic adenocarcinoma.


METHODS
A 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.


RESULTS
Mean 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 80kV (28.32±10.06 vs 19.7±7.1HU; 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.


CONCLUSIONS
Single-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.
Istituto di Radiologia, Policlinico GB Rossi, Azienda Ospedaliera Universitaria Integrata di Verona, P.le LA Scuro 10, 37134 Verona, Italy. Electronic address: gzamboni@hotmail.com.
Giulia A
GA
Zamboni
Istituto di Radiologia, Policlinico GB Rossi, Azienda Ospedaliera Universitaria Integrata di Verona, P.le LA Scuro 10, 37134 Verona, Italy. Electronic address: mchiara.ambrosetti@gmail.com.
Maria Chiara
MC
Ambrosetti
U.O. di Fisica Sanitaria, Azienda Ospedaliera Universitaria Integrata di Verona, P.le Stefani 1, 37126 Verona, Italy. Electronic address: guariglia@gmail.com.
Stefania
S
Guariglia
U.O. di Fisica Sanitaria, Azienda Ospedaliera Universitaria Integrata di Verona, P.le Stefani 1, 37126 Verona, Italy. Electronic address: carlo.cavedon@ospedaleuniverona.it.
Carlo
C
Cavedon
Istituto di Radiologia, Policlinico GB Rossi, Azienda Ospedaliera Universitaria Integrata di Verona, P.le LA Scuro 10, 37134 Verona, Italy. Electronic address: roberto.pozzimucelli@univr.it.
Roberto
R
Pozzi Mucelli
D000230:Adenocarcinoma / Q000000981:diagnostic imaging*; D000368:Aged; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D061330:Multidetector Computed Tomography / Q000379:methods*; D010190:Pancreatic Neoplasms / Q000000981:diagnostic imaging*; D019047:Phantoms, Imaging; D011829:Radiation Dosage; D011835:Radiation Protection / Q000379:methods*; D011856:Radiographic Image Enhancement / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
Computed tomography; Low-voltage technique; Pancreatic carcinoma