Noninvasive Coronary Angiography by 320-Row Computed Tomography with Lower Radiation Exposure and Maintained Diagnostic Accuracy: Comparison of Results with Cardiac Catheterization in a Head-to-Head Pilot Investigation

OBJECTIVE: Noninvasive coronary angiography with the use of multislice computed tomography (CT) scanners is feasible with high sensitivity and negative predictive value; however, the radiation exposure associated with this technique is rather high. We evaluated coronary angiography using whole-heart 320-row CT, which avoids exposure-intensive overscanning and overranging.

METHODS: A total of 30 consecutive patients with suspected coronary artery disease referred for clinically indicated conventional coronary angiography (CCA) were included in this prospective intention-to-diagnose study. CT was performed with the use of up to 320 simultaneous detector rows before same-day CCA, which, together with quantitative analysis, served as the reference standard.

RESULTS: The per-patient sensitivity and specificity for CT compared with CCA were 100% (95% confidence interval [CI], 72 to 100) and 94% (95% CI, 73 to 100), respectively. Per-vessel versus per-segment sensitivity and specificity were 89% (95% CI, 62 to 98) and 96% (95% CI, 90 to 99) versus 78% (95% CI, 56 to 91) and 98% (95% CI, 96 to 99), respectively. Interobserver agreement between the 2 readers was significantly better for CCA (97% of 121 coronary arteries) than for CT (90%; P=0.04). Percent diameter stenosis determined with the use of CT showed good correlation with CCA (P<0.001, R=0.81) without significant underestimation or overestimation (-3.1+/-24.4%; P=0.08). Intraindividual comparison of CT with CCA revealed a significantly smaller effective radiation dose (median, 4.2 versus 8.5 mSv; P<0.05) and amount of contrast agent required (median, 80 versus 111 mL; P<0.001) for 320-row CT. The majority of patients (87%) indicated that they would prefer CT over CCA for future diagnostic imaging (P<0.001).

CONCLUSIONS: CT with the use of emerging technology has the potential to significantly reduce the radiation dose and amount of contrast agent required compared with CCA while maintaining high diagnostic accuracy. 

PMID: 19704093

Posted in Computed Tomography and tagged , , , , .

3 Comments

  1. This scanner allows imaging of the heart with one table position.
    See also:
    Initial evaluation of coronary images from 320-detector row computed tomography.
    Rybicki FJ, Otero HJ, Steigner ML, et al.
    Int J Cardiovasc Imaging. 2008 Jun;24(5):535-46.
    PMID:

  2. Interesting study that shows, hidden among other findings, that there were NO un-interpretable coronary segments on CTA – all 466 segments analyzed were interpretable! However, the need for heart rates below 65 bpm was still pursued (if not always necessarily achieved). While there is no table movement in the z-position, the gantry rotation time is slower than ideal to eliminate the need of rate-control medications (even slower than some 64 row MDCT scanners in the market).

    A very interesting finding was the significant dose reduction of CTA when compared to conventional coronary angiography. But when the patients were grouped by heart rate, those with rates above 65 bpm showed a median exposure dose of 12.3 mSv (similar as to what some patients may receive during CTA examinations using 64 row MDCT scanners).

    I cannot claim to have experience with this technology. So I ask: is it necessary to scan patients with the mAs doses used in this study? To me they seem slightly elevated.

  3. Also see the recent article:

    Diagnostic accuracy of 320-row multidetector computed tomography coronary angiography in the non-invasive evaluation of significant coronary artery disease.
    de Graaf FR, Schuijf JD, van Velzen JE, Kroft LJ, de Roos A, Reiber JH, Boersma E, Schalij MJ, Spanó F, Jukema JW, van der Wall EE, Bax JJ.
    Eur Heart J. 2010 Jan 4.
    PMID:

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