Novel solid-state-detector dedicated cardiac camera for fast myocardial perfusion imaging: multicenter comparison with standard dual detector cameras

Abstract

Objective: To compare the diagnostic performance of a new dedicated ultrafast solid-state cardiac camera (Discovery NM 530c [DNM]) with standard dual detector cameras (S-SPECT) in myocardial perfusion imaging. The primary goal was a per-patient analysis of diagnostic performance of the DNM using S-SPECT as the reference standard.

Methods and results: In total, 168 patients underwent one-day Tc-99m tetrofosmin rest/stress myocardial perfusion SPECT. DNM and S-SPECT images were obtained with the same injected doses. The DNM camera uses an array of cadmium zinc telluride pixilated detectors and a multipinhole collimator simultaneously imaging all cardiac views with no moving parts. Rest and stress acquisition times were 4 and 2 minutes for DNM and 14 and 12 minutes for S-SPECT. Two blinded readers independently interpreted all scans on a patient level and on a vascular territory level using a standard five-point scale. Interobserver differences were resolved by a third observer. Agreement between DNM and S-SPECT for presence or absence of myocardial perfusion defects on a per-patient analysis was 91.9% and 92.5%, respectively. Correlation coefficients of rest and stress left ventricular ejection fractions were 0.87 (P < .01) and 0.90 (P < .01).

Conclusion: The diagnostic performance of DNM is comparable to that of S-SPECT on a per-patient basis. However, superior image quality can be achieved with significantly shorter acquisition times with DNM because of improved count sensitivity and image contrast over S-SPECT.

Figure 1

Schematic depiction of the rest/stress Tc-99m tetrofosmin myocardial perfusion imaging protocol. Standard dual-detector SPECT (S-SPECT) and DNM were performed with the same injected doses. Rest and stress DNM images were obtained immediately prior to S-SPECT images

Figure 2

Consensus agreement rates for the absence or presence of stress perfusion defects of DNM and S-SPECT₂ images using S-SPECT₁ images as the reference standard

Figure 3

Standard dual-detector SPECT (S-SPECT) (A) and DNM (B) images demonstrate reversible perfusion defects of the anterior-apical and inferior walls in a 57-year-old male. Note the improved contrast and resolution of DNM over S-SPECT

Figure 4

Consensus agreement rates between DNM-S-SPECT¹ images on a per-vessel analysis. There were no significant differences when compared to SPECT₂-S-SPECT₁ agreement rates. LAD, Left anterior descending artery; LCX, left circumflex artery; RCA, right coronary artery

Figure 5

Correlation of left ventricular rest and stress ejection fractions (A, B), end-systolic volumes (C, D), and end-diastolic volumes (E, F) between 8-frame DNM and S-SPECT images. The dark line represents the line of regression, the yellow line the line of identity

Figure 6

Bland-Altman plots depict the agreement between standard SPECT and DNM left ventricular ejection fractions (EF): rest (A) and stress (B)