Perfusion findings in (13)N-ammonia PET and CFR are strong outcome predictors. CFR allows further risk stratification, suggesting a "warranty" period of 3 years if normal CFR is associated with normal perfusion. Conversely, in patients with abnormal perfusion, an impaired CFR has added value for predicting adverse outcomes.

This first experience documents the feasibility of prospective ECG-gating for CTCA with diagnostic image quality at a low radiation dose (1.1-3.0 mSv), favouring HR <63 b.p.m.

MSCT is an independent predictor of events and provides incremental prognostic value to MPI. Combined anatomical and functional assessment may allow improved risk stratification.

We aimed at establishing the optimal scan time for nuclear myocardial perfusion imaging (MPI) on an ultrafast cardiac g-camera using a novel cadmium-zinc-telluride (CZT) solid-state detector technology. Methods: Twenty patients (17 male; BMI range, 21.7-35.5 kg/m 2 ) underwent 1-d 99m Tc-tetrofosmin adenosine stress and rest MPI protocols, each with a 15-min acquisition on a standard dual-detector SPECT camera. All scans were immediately repeated on an ultrafast CZT camera over a 6-min acquisition time and reconstructed from list-mode raw data to obtain scan durations of 1 min, 2 min, etc., up to a maximum of 6 min. For each of the scan durations, the segmental tracer uptake value (percentage of maximum myocardial uptake) from the CZT camera was compared by intraclass correlation with standard SPECT camera data using a 20-segment model, and clinical agreement was assessed per coronary territory. Scan durations above which no further relevant improvement in uptake correlation was found were defined as minimal required scan times, for which Bland-Altman limits of agreement were calculated. Results: Minimal required scan times were 3 min for low dose (r 5 0.81; P , 0.001; Bland-Altman, 211.4% to 12.2%) and 2 min for high dose (r 5 0.80; P , 0.001; Bland-Altman, 27.6% to 12.9%), yielding a clinical agreement of 95% and 97%, respectively. Conclusion: We have established the minimal scan time for a CZT solid-state detector system, which allows 1-d stress/rest MPI with a substantially reduced acquisition time resulting in excellent agreement with regard to uptake and clinical findings, compared with MPI from a standard dualhead SPECT g-camera.Key Words: clinical cardiology; SPECT; cadmium-zinc-telluride detector; myocardial perfusion imaging; ultrafast Ischemi c coronary artery disease is a major cause of morbidity and mortality in industrialized countries. The hemodynamic relevance of culprit lesions can be detected and quantified noninvasively by nuclear myocardial perfusion imaging (MPI), which has grown to become the most frequently used test in nuclear medicine (1) not only for accurate diagnosis of ischemic coronary artery disease but also for assessing prognosis and for imaging myocardial viability and function (2). However, time-consuming acquisitions and cumbersome MPI protocols, with the associated costs, impaired patient comfort, and radiation exposure, have been perceived as limitations. Several attempts to improve the MPI method by using iterative reconstruction algorithms (3,4), early-imaging protocols (5), or different tracers (6) provided valuable results but no breakthroughs translating into applications that improve daily clinical routine. The novel cadmium-zinc-telluride (CZT) detectors may have the potential to represent such a milestone in technical improvement of MPI. They offer a substantially improved count sensitivity as evidenced in preliminary reports (7) and first clinical studies (8,9) performed on a device (D-SPECT; Spectrum Dynamics) with 9 rotating CZT detectors. An alternative approach ...

Myocardial perfusion imaging with SPECT (SPECT-MPI) and 64-slice CT angiography (CTA) are both established techniques for the noninvasive evaluation of coronary artery disease (CAD). Three-dimensional (3D) SPECT/CT image fusion may offer an incremental diagnostic value by integrating both sets of information. We report our first clinical experiences with fused 3D SPECT/CT in CAD patients. Methods: Thirty-eight consecutive patients with at least 1 perfusion defect on SPECT-MPI (1-d adenosine stress/rest SPECT with 99m Tc-tetrofosmin) and 64-slice CTA were included. 3D volume-rendered fused SPECT/ CT images were generated and compared with the findings from the side-by-side analysis with regard to coronary lesion interpretation by assigning the perfusion defects to their corresponding coronary lesion. Results: The fused SPECT/CT images added information on pathophysiologic lesion severity in 27 coronary stenoses (22%) of 12 patients (29%) (P , 0.001). Among 40 equivocal lesions on side-by-side analysis, the fused interpretation confirmed hemodynamic significance in 14 lesions and excluded functional relevance in 10 lesions. In 3 lesions, assignment of perfusion defect and coronary lesion appeared to be reliable on side-by-side analysis but proved to be inaccurate on fused interpretation. Added diagnostic information by SPECT/CT was more commonly found in patients with stenoses of small vessels (P 5 0.004) and involvement of diagonal branches (P 5 0.01). Conclusion: In addition to being intuitively convincing, 3D SPECT/CT fusion images in CAD may provide added diagnostic information on the functional relevance of coronary artery lesions. A precise, noninvasive technique for the diagnosis of coronary artery disease (CAD) should provide complementary information on coronary artery anatomy and pathophysiologic lesion severity (1-4). Although this can be achieved by mental integration of the information from coronary angiography (CA) and SPECT myocardial perfusion imaging (SPECT-MPI), standard myocardial distribution territories correspond in only 50%-60% with the real anatomic coronary tree (5). Several pioneering attempts of software-based image fusion from conventional CA and SPECT-MPI have been paving the way but were not implemented into clinical practice because its invasiveness precluded its use for noninvasive preinterventional decision making (5-8).Recently, 64-slice CT angiography (CTA) has emerged as a truthful alternative to conventional CA, with excellent diagnostic accuracy, in selected patients (9,10). Combined with the advancements in fast-processing software for 3-dimensional (3D) reconstructions (11), this has allowed initial promising attempts of purely noninvasive SPECT/ CT, directly relating individual myocardial wall territories to the subtending coronary artery (12-14).The increasing interest in cardiac fusion imaging is currently raising the question of its clinical feasibility and usefulness. An evaluation seems all the more pertinent, as the integration of SPECT or PET scanners and high-end CT...

DSCT coronary angiography provides best image quality for various HRs at 70%. The ECG-pulsing window can be adapted according to the HR while maintaining diagnostic image quality.

Functionally relevant coronary artery disease: comparison of 64-section CT angiography with myocardial perfusion SPECT Gaemperli, O; Schepis, T; Valenta, I; Koepfli, P; Husmann, L; Scheffel, H; Leschka, S; Eberli, F R; Luscher, T F; Alkadhi, H; Kaufmann, P A Gaemperli, O; Schepis, T; Valenta, I; Koepfli, P; Husmann, L; Scheffel, H; Leschka, S; Eberli, F R; Luscher, T F; Alkadhi, H; Kaufmann, P A (2008 Functionally relevant coronary artery disease: comparison of 64-section CT angiography with myocardial perfusion SPECT Abstract PURPOSE: To prospectively determine the accuracy of 64-section computed tomographic (CT) angiography for the depiction of coronary artery disease (CAD) that induces perfusion defects at myocardial perfusion imaging with single photon emission computed tomography (SPECT), by using myocardial perfusion imaging as the reference standard. MATERIALS AND METHODS: All patients gave written informed consent after the study details, including radiation exposure, were explained. The study protocol was approved by the local institutional review board. In patients referred for elective conventional coronary angiography, an additional 64-section CT angiography study and a myocardial perfusion imaging study (1-day adenosine stress-rest protocol) with technetium 99m-tetrofosmin SPECT were performed before conventional angiography. Coronary artery diameter narrowing of 50% or greater at CT angiography was defined as stenosis and was compared with the myocardial perfusion imaging findings. Quantitative coronary angiography served as a reference standard for CT angiography. RESULTS: A total of 1093 coronary segments in 310 coronary arteries in 78 patients (mean age, 65 years +/-9 [standard deviation]; 35 women) were analyzed. CT angiography revealed stenoses in 137 segments (13%) corresponding to 91 arteries (29%) in 46 patients (59%). SPECT revealed 14 reversible, 13 fixed, and six partially reversible defects in 31 patients (40%). Sensitivity, specificity, and negative and positive predictive values, respectively, of CT angiography in the detection of reversible myocardial perfusion imaging defects were 95%, 53%, 94%, and 58% on a per-patient basis and 95%, 75%, 96%, and 72% on a per-artery basis. Agreement between CT and conventional angiography was very good (96% and kappa = 0.92 for patient-based analysis, 93% and kappa = 0.84 for vessel-based analysis). CONCLUSION: Sixty-four-section CT angiography can help rule out hemodynamically relevant CAD in patients with intermediate to high pretest likelihood, although an abnormal CT angiography study is a poor predictor of ischemia. Purpose:To prospectively determine the accuracy of 64-section computed tomographic (CT) angiography for the depiction of coronary artery disease (CAD) that induces perfusion defects at myocardial perfusion imaging with single photon emission computed tomography (SPECT), by using myocardial perfusion imaging as the reference standard. Materials and Methods:All patients gave written informed consent after the study details, includi...

The novel CZT camera allows a more than fivefold reduction in scan time and provides clinical information equivalent to conventional standard SPECT MPI.