title: Prospective randomised comparison of diagnostic confidence and image quality with normal-dose and low-dose CT pulmonary angiography at various body weights.
abstract: OBJECTIVE
  To find a threshold body weight (BW) below 100 kg above which computed tomography pulmonary angiography (CTPA) using reduced radiation and a reduced contrast material (CM) dose provides significantly impaired quality and diagnostic confidence compared with standard-dose CTPA.
  
  
  METHODS
  In this prospectively randomised study of 501 patients with suspected pulmonary embolism and BW <100 kg, 246 were allocated into the low-dose group (80 kVp, 75 ml CM) and 255 into the normal-dose group (100 kVp, 100 ml CM). Contrast-to-noise ratio (CNR) in the pulmonary trunk was calculated. Two blinded chest radiologists independently evaluated subjective image quality and diagnostic confidence. Data were compared between the normal-dose and low-dose groups in five BW subgroups.
  
  
  RESULTS
  Vessel attenuation did not differ between the normal-dose and low-dose groups within each BW subgroup (P = 1.0). The CNR was higher with the normal-dose compared with the low-dose protocol (P < 0.006) in all BW subgroups except for the 90-99 kg subgroup (P = 0.812). Subjective image quality and diagnostic confidence did not differ between CT protocols in all subgroups (P between 0.960 and 1.0).
  
  
  CONCLUSIONS
  Subjective image quality and diagnostic confidence with 80 kVp CTPA is not different from normal-dose protocol in any BW group up to 100 kg.
  
  
  CONCLUSIONS
  • 80 kVp CTPA is safe in patients weighing <100 kg • Reduced radiation and iodine dose still provide high vessel attenuation • Image quality and diagnostic confidence with low-dose CTPA is good • Diagnostic confidence does not deteriorate in obese patients weighing <100 kg.
authors.affiliation: University Institute of Diagnostic, Interventional and Paediatric Radiology, Inselspital, University Hospital Bern, Freiburgstrasse 10, Berne, 3010, Switzerland, zsolt.szuecs@szb-chb.ch.
authors.forename: Zsolt
authors.initials: Z
authors.lastname: Szucs-Farkas
authors.forename: Boglarka
authors.initials: B
authors.lastname: Megyeri
authors.forename: Andreas
authors.initials: A
authors.lastname: Christe
authors.forename: Peter
authors.initials: P
authors.lastname: Vock
authors.forename: Johannes T
authors.initials: JT
authors.lastname: Heverhagen
authors.forename: Sebastian T
authors.initials: ST
authors.lastname: Schindera
mesh_terms: D000792:Angiography / Q000379:methods*; D001835:Body Weight; D003287:Contrast Media; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007089:Image Enhancement; D008297:Male; D008875:Middle Aged; D061330:Multidetector Computed Tomography / Q000379:methods*; D011446:Prospective Studies; D011651:Pulmonary Artery / Q000000981:diagnostic imaging*; D011655:Pulmonary Embolism / Q000000981:diagnostic imaging*; D011829:Radiation Dosage; D015203:Reproducibility of Results
chemical_list: D003287:Contrast Media