DSPECT-specific normative limits for left ventricular size and function

Background: Differences in spatial resolution and image filtering between the solid-state DSPECT and traditional Anger SPECT (ASPECT) cameras are likely to result in differences in LV measurements. However, DSPECT-specific normal values are not available. The traditional approach of using patients deemed to have a low (< 5%) probability of coronary artery disease for the derivation of normative values has a number of limitations. We used healthy organ-donor subjects without known disease or medication use for derivation of normal values.

Methods: Subjects were 92 consecutive kidney or liver donors who underwent single-day rest (5 mCi)-stress (15 mCi) Tc-99m sestamibi-gated SPECT myocardial perfusion imaging (MPI) on the DSPECT camera for pre-operative evaluation and had normal perfusion and LV function. Exclusion criteria included any known cardiac disease or medications. LV measurements were made on the post-stress supine stress images using QGS®.

Results: Of 92 subjects (mean age 54.4 ± 15.0 and 39% men), mean EF ± 2SD for women and men was 77.2% ± 14.1% and 70.0 % ± 14.7%, respectively. Mean end-diastolic volume ± 2SD for women and men was 67.0 ± 32.2 mL and 99.6 ± 51.6 mL (indexed 38.3 ± 17.2 mL/m² and 48.1 ± 25.9 mL/m²), respectively. Mean end-systolic volume ± 2SD for women and men was 16.1 ± 15.7 mL and 31.2 ± 29.2 mL (indexed 9.2 ± 8.8 mL/m² and 15.0 ± 14.2 mL/m²), respectively. Mean LV wall volume ± 2SD for women and men was 95.9 ± 26.0 mL and 112.0 ± 48.8 mL (indexed 55.0 ± 13.8 mL/m² and 54.1 ± 24.6 mL/m²), respectively.

Conclusion: We report DSPECT-specific LV measurements from normal subjects from which limits of normality can be derived for clinic use. Organ donors who undergo pre-operative MPI are a suitable cohort for the derivation of normal values.