title: Individualized CT Angiography Protocols for the Evaluation of the Aorta: A Feasibility Study.
abstract: OBJECTIVE
  Ionizing radiation and iodinated contrast media are potential drawbacks to repetitive follow-up CT angiography in current practice. The aim of the present study was to optimize radiation dose and contrast agent volume by using individualized CT angiography protocols.
  
  
  METHODS
  Eighty consecutive patients referred for CT angiography of the whole aorta were prospectively evaluated. Patients were divided into groups of patients with a body mass index (BMI) < 28 kg/m(2) (group 1; n = 50) and those with a BMI ≥ 28 kg/m(2) (group 2; n = 30). A control group consisted of 50 consecutive patients who were retrospectively evaluated. CT angiography parameters on a second-generation dual-source scanner were 128 × 0.6-mm collimation, pitch of 0.9, rotation time of 0.33 seconds, tube voltages of 80/100/120 kVp (group 1/group 2/control), reference tube current of 400 mA, and image reconstruction at 1-mm/0.8-mm slice thickness (kernels, B30f [control] and I30f/strength 3 [groups 1/2]). The control group received 120 mL of contrast agent (300 mgI/mL) at 4.8 mL/s; groups 1 and 2 received 44 mL and 53 mL at 3.3 mL/s and 4 mL/s, respectively. Effective dose was evaluated for each patient. Image quality was determined by qualitative image analysis at the levels of the thoracic, abdominal, and pelvic aorta as nondiagnostic, diagnostic, good, or excellent, and quantitative image analysis was performed, including attenuation values and contrast-to-noise ratio (CNR).
  
  
  RESULTS
  Mean effective radiation dose values for CT angiography of the aorta were 3.7 mSv ± 0.7 in group 1, 6.7 mSv ± 1.4 in group 2, and 8.7 mSv ± 1.9 in the control group (P < .001). Mean attenuation values and CNR levels were 334 HU ± 66 and 16 ± 8, respectively, in group 1, 277 HU ± 56 and 14 ± 5 in group 2, and 305 HU ± 77 and 11 ± 4 in the control group.
  
  
  CONCLUSIONS
  Iterative reconstruction algorithms resulted in 23%-57% less radiation in combination with 55%-63% less contrast agent volume compared with standard CT protocols.
authors.affiliation: Department of Radiology, Maastricht University Medical Center, P. Debyelaan 25, P.O. Box 5800, 6202 AZ Maastricht, The Netherlands; CARIM School for Cardiovascular Diseases, Maastricht University Medical Center, P. Debyelaan 25, P.O. Box 5800, 6202 AZ Maastricht, The Netherlands.
authors.forename: Madeleine
authors.initials: M
authors.lastname: Kok
authors.affiliation: Department of Radiology, Maastricht University Medical Center, P. Debyelaan 25, P.O. Box 5800, 6202 AZ Maastricht, The Netherlands.
authors.forename: Michael W
authors.initials: MW
authors.lastname: de Haan
authors.affiliation: Department of Radiology, Maastricht University Medical Center, P. Debyelaan 25, P.O. Box 5800, 6202 AZ Maastricht, The Netherlands; CARIM School for Cardiovascular Diseases, Maastricht University Medical Center, P. Debyelaan 25, P.O. Box 5800, 6202 AZ Maastricht, The Netherlands.
authors.forename: Casper
authors.initials: C
authors.lastname: Mihl
authors.affiliation: Department of Radiology, Maastricht University Medical Center, P. Debyelaan 25, P.O. Box 5800, 6202 AZ Maastricht, The Netherlands.
authors.forename: Nienke G
authors.initials: NG
authors.lastname: Eijsvoogel
authors.affiliation: Department of Radiology, Maastricht University Medical Center, P. Debyelaan 25, P.O. Box 5800, 6202 AZ Maastricht, The Netherlands.
authors.forename: Babs M F
authors.initials: BM
authors.lastname: Hendriks
authors.affiliation: Department of Radiology, Maastricht University Medical Center, P. Debyelaan 25, P.O. Box 5800, 6202 AZ Maastricht, The Netherlands; Department of Radiology, Stanford Hospital and Clinics, Stanford, California.
authors.forename: Anna M
authors.initials: AM
authors.lastname: Sailer
authors.affiliation: Department of Radiology, Maastricht University Medical Center, P. Debyelaan 25, P.O. Box 5800, 6202 AZ Maastricht, The Netherlands.
authors.forename: Kris
authors.initials: K
authors.lastname: Derks
authors.affiliation: Department of Radiology, Maastricht University Medical Center, P. Debyelaan 25, P.O. Box 5800, 6202 AZ Maastricht, The Netherlands.
authors.forename: Roald S
authors.initials: RS
authors.lastname: Schnerr
authors.affiliation: Vascular Surgery, Maastricht University Medical Center, P. Debyelaan 25, P.O. Box 5800, 6202 AZ Maastricht, The Netherlands.
authors.forename: Geert Willem H
authors.initials: GW
authors.lastname: Schurink
authors.affiliation: Department of Radiology, Maastricht University Medical Center, P. Debyelaan 25, P.O. Box 5800, 6202 AZ Maastricht, The Netherlands; CARIM School for Cardiovascular Diseases, Maastricht University Medical Center, P. Debyelaan 25, P.O. Box 5800, 6202 AZ Maastricht, The Netherlands.
authors.forename: Joachim E
authors.initials: JE
authors.lastname: Wildberger
authors.affiliation: Department of Radiology, Maastricht University Medical Center, P. Debyelaan 25, P.O. Box 5800, 6202 AZ Maastricht, The Netherlands; CARIM School for Cardiovascular Diseases, Maastricht University Medical Center, P. Debyelaan 25, P.O. Box 5800, 6202 AZ Maastricht, The Netherlands. Electronic address: m.das@mumc.nl.
authors.forename: Marco
authors.initials: M
authors.lastname: Das
mesh_terms: D000368:Aged; D000465:Algorithms; D001011:Aorta / Q000000981:diagnostic imaging*; D001027:Aortography / Q000379:methods*; D000072226:Computed Tomography Angiography; D003287:Contrast Media / Q000008:administration & dosage; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007472:Iohexol / Q000008:administration & dosage / Q000031:analogs & derivatives; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D011829:Radiation Dosage; D000069079:Radiation Exposure; D011857:Radiographic Image Interpretation, Computer-Assisted; D015203:Reproducibility of Results; D012189:Retrospective Studies; D059629:Signal-To-Noise Ratio
chemical_list: D003287:Contrast Media; D007472:Iohexol; C038192:iopromide