Novel Ultrafast Cardiac Dedicated SPECT-CT Enables Major Reductions in Patient Dose and Scan Time, While Synergistically Obtaining High Quality Diagnostic Images of Cardiac Anatomy and Function in a Single Scan Session

usingCSPAMM.Histological validationwasperformedby biopsy of the LV septal and free walls during AV surgery. Results: Sixty-three subjects (Severe AS, n= 25; Hypertension, n= 19; Healthy control, n= 19) were recruited. Subjects with HT and severe AS displayed higher Ve compared to healthy controls (p< 0.01). AS patients with elevated Ve also displayed increased levels of both interstitial and replacement fibrosis onhistology (Figs. A andB, respectively). Significant heterogeneity in fibrosis burden existed with LV anterior free wall fibrosis (Fig. C) significant lower when compared with the septum (p< 0.01, Fig. D). The Ve correlated with indices of reduced myocardial function including reduced circumferential strain (r=−0.69, p= 0.001), and radial strain (r=−0.59, p= 0.03). Conclusions:Multi-slice T1-mapping-derived Ve is significantly elevated in patients with AS and systemic hypertension and correlates well with histology and reduced myocardial performance. This technique is clinically practical and holds promise for the detection of IMF in pressure overload hypertrophy. Method: Comparison was made between the conventional state-of-the-art (Philips Precedence) SPECT-CT hybrid camera with the Discovery 570c SPECT-CT hybrid camera in 25 randomly selectedpatients fromeach camera (single day scan protocol). Diagnostic image quality was maintained while scan times and doses were compared for both rest and stress sestamibi myocardial perfusion images as well as for the CT component. Results: Effective doses for CT Philips CT (no ASIR) GE570c (with ASIR) CT for both calcium score and attenuation correction (AC) 0.86 ± 0.05mSv (mean±SD) 0.77 ± 0.09mSv (mean±SD) CT for AC only 0.74 ± 0.03mSv 0.18 ± 0.03mSv SPECT data Philips injected activity Philips effective dose Philips scan time GE570c injected activity GE570c effective dose GE570c scan time Rest 300MBq 2.70mSv 14min 100MBq 0.90mSv 10min Stress 900MBq 7.11mSv 7min 300MBq 2.37mSv 6min Conclusion: The GE Discovery 570c SPECT-CT with ASIR enablesmajor reductions in both radiation dose and scanning time while maintaining high image quality. An ultralow dose stress only (100MBq) SPECT-CT protocol including calcium score with an estimated total (SPECT plus CT) effective radiation dose of 1.6mSv is achievable. http://dx.doi.org/10.1016/j.hlc.2012.05.533 http://dx.doi.org/10.1016/j.hlc.2012.05.532