title: Reduced time CT perfusion acquisitions are sufficient to measure the permeability surface area product with a deconvolution method.
abstract: OBJECTIVE
  To reduce the radiation dose, reduced time CT perfusion (CTp) acquisitions are tested to measure permeability surface (PS) with a deconvolution method.
  
  
  METHODS
  PS was calculated with repeated measurements (n = 305) while truncating the time density curve (TDC) at different time values in 14 CTp studies using CTp 4D software (GE Healthcare, Milwaukee, WI, US). The median acquisition time of CTp studies was 59.35 sec (range 49-92 seconds). To verify the accuracy of the deconvolution algorithm, a variation of the truncated PS within the error measurements was searched, that is, within 3 standard deviations from the mean nominal error provided by the software. The test was also performed for all the remaining CTp parameters measured.
  
  
  RESULTS
  PS maximum variability happened within 25 seconds. The PS became constant after 40 seconds for the majority of the active tumors (10/11), while for necrotic tissues it was consistent within 1% after 50 seconds. A consistent result lasted for all the observed CTp parameters, as expected from their analytical dependance.
  
  
  CONCLUSIONS
  40-second acquisition time could be an optimal compromise to obtain an accurate measurement of the PS and a reasonable dose exposure with a deconvolution method.
authors.affiliation: Department of Diagnostic Imaging, Azienda Ospedaliera Universitaria Senese, Viale Bracci 10, 53100 Siena, Italy.
authors.forename: Francesco Giuseppe
authors.initials: FG
authors.lastname: Mazzei
authors.affiliation: Department of Medical, Surgical and Neuro Sciences, Diagnostic Imaging, University of Siena, Viale Bracci 10, 53100 Siena, Italy.
authors.forename: Luca
authors.initials: L
authors.lastname: Volterrani
authors.affiliation: Department of Medical, Surgical and Neuro Sciences, Diagnostic Imaging, University of Siena, Viale Bracci 10, 53100 Siena, Italy.
authors.forename: Susanna
authors.initials: S
authors.lastname: Guerrini
authors.affiliation: Department of Medical, Surgical and Neuro Sciences, Diagnostic Imaging, University of Siena, Viale Bracci 10, 53100 Siena, Italy.
authors.forename: Nevada
authors.initials: N
authors.lastname: Cioffi Squitieri
authors.affiliation: Department of Physics, Osservatorio Astrofisico di Arcetri, Largo Enrico Fermi 5, 50125 Florence, Italy.
authors.forename: Eleonora
authors.initials: E
authors.lastname: Sani
authors.affiliation: Department of Medical, Surgical and Neuro Sciences, Diagnostic Imaging, University of Siena, Viale Bracci 10, 53100 Siena, Italy.
authors.forename: Gloria
authors.initials: G
authors.lastname: Bettini
authors.affiliation: Department of Medical, Surgical and Neuro Sciences, Diagnostic Imaging, University of Siena, Viale Bracci 10, 53100 Siena, Italy.
authors.forename: Chiara
authors.initials: C
authors.lastname: Pozzessere
authors.affiliation: Department of Medical, Surgical and Neuro Sciences, Diagnostic Imaging, University of Siena, Viale Bracci 10, 53100 Siena, Italy.
authors.forename: Maria Antonietta
authors.initials: MA
authors.lastname: Mazzei
mesh_terms: D003287:Contrast Media / Q000737:chemistry; D006801:Humans; D008297:Male; D008875:Middle Aged; D010477:Perfusion / Q000379:methods; D055420:Perfusion Imaging / Q000379:methods*; D010539:Permeability; D011829:Radiation Dosage; D015203:Reproducibility of Results; D012984:Software; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D003287:Contrast Media