Prospective gating with 320-MDCT angiography: Effect of volume scan length on radiation dose

Atif Khan, Khurram Nasir, Faisal Khosa, Amina Saghir, Sheryar Sarwar, Melvin E. Clouse

Research output: Contribution to journalArticlepeer-review

28 Scopus citations


OBJECTIVE. The purpose of this study was to evaluate the relation between radiation dose reduction and volume scan length for prospectively ECG-gated 320-MDCT angiography in the diagnosis of coronary artery disease. MATERIALS AND METHODS. MDCT with prospective ECG gating was performed at one of the three volume scan lengths depending on heart length. Of 175 patients, 95 (55%; body mass index, 29 ± 5.9; mean heart rate, 59 ± 7 beats/min) underwent scanning at 160 mm; 46 (26%; body mass index, 30 ± 4.1; mean heart rate, 56 ± 5.74 beats/min) at 140 mm; and 34 (19%; body mass index, 30 ± 3.71; mean heart rate, 58 ± 3.96 beats/min) at 120 mm. RESULTS. The median radiation doses were 6.5 mSv (95% CI, 6.03-7.2 mSv) for the 95 patients who underwent scanning at a volume scan length of 160 mm, 4.33 mSv (95% CI, 4.06-6.62 mSv) for the 46 patients who underwent scanning at 140 mm, and 3.47 mSv (95% CI, 3.15-3.62 mSv) for the 34 patients who underwent scanning at 120 mm. The reduction in scan length from 160 to 140 mm represented a reduction in scan length of 12.5% and the reduction to 120 mm a reduction of 25%. The median radiation dose was reduced 33% when volume scan length was changed to 140 mm and 47% when the length was changed to 120 mm. CONCLUSION. Dose optimization remains an important concern in cardiac CT, and for 320-MDCT angiography, substantial dose reduction can be achieved by reducing volume scan length so that it is in concert with the patient's heart length.

Original languageEnglish (US)
Pages (from-to)407-411
Number of pages5
JournalAmerican Journal of Roentgenology
Issue number2
StatePublished - Feb 2011


  • 320-MDCT
  • Cardiac imaging
  • Coronary artery disease
  • Radiation dose reduction
  • Volume scan length

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging


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