Comparison of postprocessing techniques for the detection of perfusion defects by cardiac computed tomography in patients presenting with acute ST-segment elevation myocardial infarction

Department of Radiology and Division of Cardiology, Massachusetts General Hospital, Boston, MA 02114-2750, USA.
Journal of cardiovascular computed tomography (Impact Factor: 2.29). 07/2010; 4(4):258-66. DOI: 10.1016/j.jcct.2010.04.003
Source: PubMed


Despite rapid advances in cardiac computed tomography (CT), a strategy for optimal visualization of perfusion abnormalities on CT has yet to be validated.
We evaluated the performance of several postprocessing techniques of source data sets to detect and characterize perfusion defects in acute myocardial infarctions with cardiac CT.
Twenty-one subjects (18 men; 60 +/- 13 years) that were successfully treated with percutaneous coronary intervention for ST-segment myocardial infarction underwent 64-slice cardiac CT and 1.5 Tesla cardiac magnetic resonance imaging (MRI) scans after revascularization. Delayed enhancement MR images were analyzed to identify the location of infarcted myocardium. Contiguous short-axis images of the left ventricular myocardium were created from the CT source images with 0.75-mm multiplanar reconstruction (MPR), 5-mm MPR, 5-mm maximal intensity projection (MIP), and 5-mm minimum intensity projection (MinIP) techniques. Segments already confirmed to contain infarction by MRI were then evaluated qualitatively and quantitatively with CT.
Overall, 143 myocardial segments were analyzed. On qualitative analysis, the MinIP and thick MPR techniques had greater visibility and definition than the thin MPR and MIP techniques (P < 0.001). On quantitative analysis, the absolute difference in Hounsfield unit attenuation between normal and infarcted segments was significantly greater for the MinIP (65.4 Hounsfield unit [HU]) and thin MPR (61.2 HU) techniques. However, the relative difference in Hounsfield unit attenuation was significantly greatest for the MinIP technique alone (95%; P < 0.001). Contrast to noise was greatest for the MinIP (4.2) and thick MPR (4.1) techniques (P < 0.001).
The results of our current investigation found that MinIP and thick MPR detected infarcted myocardium with greater visibility and definition than MIP and thin MPR.

Download full-text


Available from: Michael David Shapiro, Jul 09, 2014
  • Source
    • "For both rest and stress CTP evaluation times necessary for angulation of the cardiac axes, automated epi- and endocardial contour detection with the following manual correction, and short axis documentation were recorded manually by each reader. The resulting short-axis view was documented by screenshots in steps of 3 mm and a slice thickness of 8 mm with a "black and white" preset (window level [wl] of 100 and a window width [ww] of 200; as proposed by Rogers et al. [20]) and "rainbow-red" preset (wl 200/ww 350). Using the black and white short-axis view, the subjective evaluation of automated epi- and endocardial contour detection was performed based on necessity for manual corrections. "
    [Show abstract] [Hide abstract]
    ABSTRACT: We aimed to evaluate the time efficiency and diagnostic accuracy of automated myocardial computed tomography perfusion (CTP) image analysis software. 320-row CTP was performed in 30 patients, and analyses were conducted independently by three different blinded readers by the use of two recent software releases (version 4.6 and novel version 4.71GR001, Toshiba, Tokyo, Japan). Analysis times were compared, and automated epi- and endocardial contour detection was subjectively rated in five categories (excellent, good, fair, poor and very poor). As semi-quantitative perfusion parameters, myocardial attenuation and transmural perfusion ratio (TPR) were calculated for each myocardial segment and agreement was tested by using the intraclass correlation coefficient (ICC). Conventional coronary angiography served as reference standard. The analysis time was significantly reduced with the novel automated software version as compared with the former release (Reader 1: 43:08 ± 11:39 min vs. 09:47 ± 04:51 min, Reader 2: 42:07 ± 06:44 min vs. 09:42 ± 02:50 min and Reader 3: 21:38 ± 3:44 min vs. 07:34 ± 02:12 min; p < 0.001 for all). Epi- and endocardial contour detection for the novel software was rated to be significantly better (p < 0.001) than with the former software. ICCs demonstrated strong agreement (≥ 0.75) for myocardial attenuation in 93% and for TPR in 82%. Diagnostic accuracy for the two software versions was not significantly different (p = 0.169) as compared with conventional coronary angiography. The novel automated CTP analysis software offers enhanced time efficiency with an improvement by a factor of about four, while maintaining diagnostic accuracy.
    Korean journal of radiology: official journal of the Korean Radiological Society 01/2013; 14(1):21-9. DOI:10.3348/kjr.2013.14.1.21 · 1.57 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Direct comparison of CT and magnetic resonance (MR) perfusion techniques has been limited and in vivo assessment is affected by physiological variability, timing of image acquisition, and parameter selection. We precisely compared high-resolution k-t SENSE MR cardiac perfusion at 3 T with single-phase CT perfusion (CTP) under identical imaging conditions. We used a customized MR imaging and CT compatible dynamic myocardial perfusion phantom to represent the human circulation. CT perfusion studies were performed with a Philips iCT (256 slice) CT, with isotropic resolution of 0.6 mm(3). MR perfusion was performed with k-t SENSE acceleration at 3 T and spatial resolution of 1.2 × 1.2 × 10 mm. The image contrast between normal and underperfused myocardial compartments was quantified at various perfusion and photon energy settings. Noise estimates were based on published clinical data. Contrast by CTP highly depends on photon energy and also timing of imaging within the myocardial perfusion upslope. For an identical myocardial perfusion deficit, the native image contrast-to-noise ratio (CNR) generated by CT and MR are similar. If slice averaging is used, the CNR of a perfusion deficit is expected to be greater for CTP than MR perfusion (MRP). Perfect timing during single time point CTP imaging is difficult to achieve, and CNR by CT decreases by 24%-31% two seconds from the optimal imaging time point. Although single-phase CT perfusion offers higher spatial resolution, MRP allows multiple time point sampling and quantitative analysis. The ability of CTP and current optimal MRP techniques to detect simulated myocardial perfusion deficits is similar.
    Journal of cardiovascular computed tomography 03/2013; 7(2):117-24. DOI:10.1016/j.jcct.2013.01.016 · 2.29 Impact Factor

  • Journal of cardiovascular computed tomography 07/2010; 4(4):274-5. DOI:10.1016/j.jcct.2010.05.006 · 2.29 Impact Factor
Show more