Detection of pancreatic tumors, image quality, and radiation dose during the pancreatic parenchymal phase: effect of a low-tube-voltage, high-tube-current CT technique--preliminary results.

PURPOSE To intraindividually compare a low-tube-voltage (80 kVp), high-tube-current (675 mA) computed tomographic (CT) technique with a high-tube-voltage (140 kVp) CT protocol for the detection of pancreatic tumors, image quality, and radiation dose during the pancreatic parenchymal phase. MATERIALS AND METHODS This prospective, single-center, HIPAA-compliant study was approved by the institutional review board, and written informed consent was obtained. Twenty-seven patients (nine men, 18 women; mean age, 64 years) with 23 solitary pancreatic tumors underwent dual-energy CT. Two imaging protocols were used: 140 kVp and 385 mA (protocol A) and 80 kVp and 675 mA (protocol B). For both protocols, the following variables were compared during the pancreatic parenchymal phase: contrast enhancement for the aorta, the pancreas, and the portal vein; pancreas-to-tumor contrast-to-noise ratio (CNR); noise; and effective dose. Two blinded, independent readers qualitatively scored the two data sets for tumor detection and image quality. Random-effect analysis of variance tests were used to compare differences between the two protocols. RESULTS Compared with protocol A, protocol B yielded significantly higher contrast enhancement for the aorta (508.6 HU vs 221.5 HU, respectively), pancreas (151.2 HU vs 67.0 HU), and portal vein (189.7 HU vs 87.3 HU), along with a greater pancreas-to-tumor CNR (8.1 vs 5.9) (P < .001 for all comparisons). No statistically significant difference in tumor detection was observed between the two protocols. Although standard deviation of image noise increased with protocol B (11.5 HU vs 18.6 HU), this protocol significantly reduced the effective dose (from 18.5 to 5.1 mSv; P < .001). CONCLUSION A low-tube-voltage, high-tube-current CT technique has the potential to improve the enhancement of the pancreas and peripancreatic vasculature, improve tumor conspicuity, and reduce patient radiation dose during the pancreatic parenchymal phase.

[1]  B. Yeh,et al.  Dual-energy and low-kVp CT in the abdomen. , 2009, AJR. American journal of roentgenology.

[2]  Ehsan Samei,et al.  Hypervascular liver tumors: low tube voltage, high tube current multidetector CT during late hepatic arterial phase for detection--initial clinical experience. , 2009, Radiology.

[3]  D. Hough,et al.  Dual-energy and dual-source CT: is there a role in the abdomen and pelvis? , 2009, Radiologic clinics of North America.

[4]  A. Jemal,et al.  Cancer Statistics, 2008 , 2008, CA: a cancer journal for clinicians.

[5]  Ehsan Samei,et al.  Hypervascular liver tumors: low tube voltage, high tube current multi-detector row CT for enhanced detection--phantom study. , 2008, Radiology.

[6]  C. Heyer,et al.  Image quality and radiation exposure at pulmonary CT angiography with 100- or 120-kVp protocol: prospective randomized study. , 2007, Radiology.

[7]  J. Kruskal,et al.  Comprehensive preoperative assessment of pancreatic adenocarcinoma with 64-section volumetric CT. , 2007, Radiographics : a review publication of the Radiological Society of North America, Inc.

[8]  D. Frush,et al.  Validation of metal oxide semiconductor field effect transistor technology for organ dose assessment during CT: comparison with thermoluminescent dosimetry. , 2007, AJR. American journal of roentgenology.

[9]  Annet Waaijer,et al.  Circle of Willis at CT angiography: dose reduction and image quality--reducing tube voltage and increasing tube current settings. , 2007, Radiology.

[10]  M. Kanematsu,et al.  MDCT of the pancreas: optimizing scanning delay with a bolus-tracking technique for pancreatic, peripancreatic vascular, and hepatic contrast enhancement. , 2007, AJR. American journal of roentgenology.

[11]  16-MDCT angiography in living kidney donors at various tube potentials: impact on image quality and radiation dose. , 2007, AJR. American journal of roentgenology.

[12]  Mathias Prokop,et al.  CT angiography of pulmonary arteries to detect pulmonary embolism: improvement of vascular enhancement with low kilovoltage settings. , 2006, Radiology.

[13]  R. Prokesch,et al.  Multidetector CT of pancreas: effects of contrast material flow rate and individualized scan delay on enhancement of pancreas and tumor contrast. , 2006, Radiology.

[14]  M. Kanematsu,et al.  Pancreas: optimal scan delay for contrast-enhanced multi-detector row CT. , 2006, Radiology.

[15]  Takeshi Nakaura,et al.  Abdominal CT with low tube voltage: preliminary observations about radiation dose, contrast enhancement, image quality, and noise. , 2005, Radiology.

[16]  Ehsan Samei,et al.  A framework for optimising the radiographic technique in digital X-ray imaging. , 2005, Radiation protection dosimetry.

[17]  E. Merkle,et al.  Effect of iodine concentration of contrast media on contrast enhancement in multislice CT of the pancreas. , 2004, The British journal of radiology.

[18]  J. Paul,et al.  Low-kilovoltage multi-detector row chest CT in adults: feasibility and effect on image quality and iodine dose. , 2004, Radiology.

[19]  E. Nickoloff,et al.  Influence of phantom diameter, kVp and scan mode upon computed tomography dose index. , 2003, Medical physics.

[20]  M. Ishibashi,et al.  Assessment of pancreatic CT enhancement using a high concentration of contrast material. , 2003, Radiation medicine.

[21]  D. Rennie,et al.  Towards complete and accurate reporting of studies of diagnostic accuracy: the STARD initiative , 2003, BMJ : British Medical Journal.

[22]  R. Jeffrey,et al.  Local staging of pancreatic carcinoma with multi-detector row CT: use of curved planar reformations initial experience. , 2002, Radiology.

[23]  R. Jeffrey,et al.  Isoattenuating pancreatic adenocarcinoma at multi-detector row CT: secondary signs. , 2002, Radiology.

[24]  J. Platt,et al.  Multi--detector row helical CT of the pancreas: effect of contrast-enhanced multiphasic imaging on enhancement of the pancreas, peripancreatic vasculature, and pancreatic adenocarcinoma. , 2001, Radiology.

[25]  W Huda,et al.  Technique factors and image quality as functions of patient weight at abdominal CT. , 2000, Radiology.

[26]  T. Murakami,et al.  Pancreatic CT imaging: effects of different injection rates and doses of contrast material. , 1999, Radiology.

[27]  M. Tublin,et al.  Effect of injection rate of contrast medium on pancreatic and hepatic helical CT. , 1999, Radiology.

[28]  D. Lu,et al.  Two-phase helical CT for pancreatic tumors: pancreatic versus hepatic phase enhancement of tumor, pancreas, and vascular structures. , 1996, Radiology.

[29]  A. Scott,et al.  A simple method for the analysis of clustered binary data. , 1992, Biometrics.

[30]  J. R. Landis,et al.  The measurement of observer agreement for categorical data. , 1977, Biometrics.