title: Improved sensitivity of computed tomography towards iodine and gold nanoparticle contrast agents via iterative reconstruction methods.
abstract: Computed tomography is a widely used medical imaging technique that has high spatial and temporal resolution. Its weakness is its low sensitivity towards contrast media. Iterative reconstruction techniques (ITER) have recently become available, which provide reduced image noise compared with traditional filtered back-projection methods (FBP), which may allow the sensitivity of CT to be improved, however this effect has not been studied in detail. We scanned phantoms containing either an iodine contrast agent or gold nanoparticles. We used a range of tube voltages and currents. We performed reconstruction with FBP, ITER and a novel, iterative, modal-based reconstruction (IMR) algorithm. We found that noise decreased in an algorithm dependent manner (FBP > ITER > IMR) for every scan and that no differences were observed in attenuation rates of the agents. The contrast to noise ratio (CNR) of iodine was highest at 80 kV, whilst the CNR for gold was highest at 140 kV. The CNR of IMR images was almost tenfold higher than that of FBP images. Similar trends were found in dual energy images formed using these algorithms. In conclusion, IMR-based reconstruction techniques will allow contrast agents to be detected with greater sensitivity, and may allow lower contrast agent doses to be used.
authors.affiliation: Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA.
authors.forename: Ally Leigh
authors.initials: AL
authors.lastname: Bernstein
authors.affiliation: Philips Healthcare, Highland Heights, OH, USA.
authors.forename: Amar
authors.initials: A
authors.lastname: Dhanantwari
authors.affiliation: Department of Radiology, University of Pennsylvania, 3400 Spruce St, 1 Silverstein, Philadelphia, PA 19104, USA.
authors.forename: Martina
authors.initials: M
authors.lastname: Jurcova
authors.affiliation: Department of Radiology, University of Pennsylvania, 3400 Spruce St, 1 Silverstein, Philadelphia, PA 19104, USA.
authors.forename: Rabee
authors.initials: R
authors.lastname: Cheheltani
authors.affiliation: Department of Radiology, University of Pennsylvania, 3400 Spruce St, 1 Silverstein, Philadelphia, PA 19104, USA.
authors.forename: Pratap Chandra
authors.initials: PC
authors.lastname: Naha
authors.affiliation: Philips Healthcare, Highland Heights, OH, USA.
authors.forename: Thomas
authors.initials: T
authors.lastname: Ivanc
authors.affiliation: Philips Healthcare, Highland Heights, OH, USA.
authors.forename: Efrat
authors.initials: E
authors.lastname: Shefer
authors.affiliation: Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA.|Department of Radiology, University of Pennsylvania, 3400 Spruce St, 1 Silverstein, Philadelphia, PA 19104, USA.|Division of Cardiovascular Medicine, University of Pennsylvania, Philadelphia, PA, USA.
authors.forename: David Peter
authors.initials: DP
authors.lastname: Cormode
mesh_terms: D003287:Contrast Media / Q000008:administration & dosage*; D006046:Gold / Q000008:administration & dosage*; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D007455:Iodine / Q000008:administration & dosage*; D008962:Models, Theoretical; D053758:Nanoparticles / Q000008:administration & dosage*; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D003287:Contrast Media; D006046:Gold; D007455:Iodine