title: Low-dose triple-rule-out using 320-row-detector volume MDCT--less contrast medium and lower radiation exposure.
abstract: OBJECTIVE
  To investigate image quality of triple-rule-out (TRO) computed tomography (CT) using a 320-row-detector CT system with substantially reduced contrast medium volume at 100 kV.
  
  
  METHODS
  Forty-six consecutive patients with noncritical, acute chest pain underwent 320-row-detector CT using a two-step TRO protocol consisting of a non-spiral, non-gated chest CT acquisition (150 mA) followed by a non-spiral, electrocardiography-gated cardiac acquisition (200-500 mA based on body mass index (BMI)). Data were acquired using a biphasic injection protocol with a total iodinated contrast medium volume of 60 ml (370 mg/ml). Vessel attenuation and effective doses were recorded. Image quality was scored independently by two readers.
  
  
  RESULTS
  Mean attenuation was 584 ± 114 Hounsfield units (HU) in the ascending aorta, 335 ± 63HU in the aortic arch, 658 ± 136HU in the pulmonary trunk, and 521 ± 97HU and 549 ± 102HU in the right and left coronary artery, respectively. In all but one patient, attenuation and image quality allowed accurate visualization of the pulmonary arteries, thoracic aorta, and coronary arteries in a single examination. Ninety-six percent of all coronary artery segments were rated diagnostic. Radiation exposure ranged between 2.0 and 3.3 mSv.
  
  
  CONCLUSIONS
  Using 320-row-detector CT the investigated low-dose TRO protocol resulted in excellent opacification and image quality with substantial reduction of contrast medium volume compared to recently published TRO protocols.
authors.affiliation: Department of Radiology, Charité-University Hospital Berlin, Campus Mitte, 10117 Berlin, Germany. tahir.durmus@charite.de
authors.forename: Tahir
authors.initials: T
authors.lastname: Durmus
authors.forename: Patrik
authors.initials: P
authors.lastname: Rogalla
authors.forename: Alexander
authors.initials: A
authors.lastname: Lembcke
authors.forename: Matthias R
authors.initials: MR
authors.lastname: Mühler
authors.forename: Bernd
authors.initials: B
authors.lastname: Hamm
authors.forename: Patrick A
authors.initials: PA
authors.lastname: Hein
mesh_terms: D015992:Body Mass Index; D002637:Chest Pain / Q000000981:diagnostic imaging*; D003287:Contrast Media / Q000008:administration & dosage; D004562:Electrocardiography; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D007472:Iohexol / Q000008:administration & dosage / Q000031:analogs & derivatives; D008297:Male; D008875:Middle Aged; D011829:Radiation Dosage; D011857:Radiographic Image Interpretation, Computer-Assisted; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D003287:Contrast Media; D007472:Iohexol; C038192:iopromide