Prognostic Value of Diastolic Dysfunction Derived From D-SPECT in Coronary Artery Disease Patients With Normal Ejection Fraction

A comparison between 64-projection and 32-projection myocardial perfusion scintigraphy

Aims

While most clinical guidelines recommend using a 64-projection view technique, some protocols do not specify a preference between 32-projection and 64-projection methods for conducting myocardial perfusion scintigraphy (MPS), which shows the lack of consensus in this matter. Nevertheless, these guidelines and protocols have not provided us with compelling evidence to support why the 64-projection technique is usually chosen. Thus, we aimed to determine if there is a significant difference between them in the assessment of cardiac perfusion and functional indices.

Methods and results

Sixty-nine patients were included in this pilot prospective, cross-sectional, cross-over, same patient control protocol study and underwent 32- and 64-projection MPS at both stress and rest phases after injecting 740-925 MBq of 99mTc-MIBI for every patient. Then, cardiac indices, including summed stress, rest, and difference scores, extent-stress and rest, left ventricular volumes and ejection-fraction, peak filling rate (PFR), and time to peak filling rate (TTPF) were recorded. Lin's concordance correlation coefficient was used to assess the agreement between protocols, and a paired sample t-test was used to compare the means of variables where appropriate. Findings revealed no significant difference as well as excellent/good agreement between the two methods in either the stress or rest state, except for the TTPF and PFR.

Conclusion

The findings suggest that lower-projection techniques could be adequate for routine clinical assessments without sacrificing diagnostic accuracy. However, the poor agreement for PFR and TTPF indicates that the 32-projection method may not reliably assess diastolic function, implying that the 64-projection protocol is preferable when precise evaluations are necessary.

P-Wave Terminal Force V1 Is Associated with Left Ventricular Diastolic Function in Patients with No Significant Perfusion Abnormality

P-wave terminal force in lead V1 (PTFV1) is a marker of increased left atrial (LA) overload. Whether PTFV1 is associated with left ventricular (LV) diastolic function remains undetermined. We tested the hypothesis that PTFV1 is associated with LV diastolic parameters derived from gated myocardial perfusion single-photon emission computed tomography (SPECT) in patients with no significant perfusion abnormalities.The study population included 158 patients with preserved ejection fraction and no significant perfusion abnormalities. The amplitude and duration of the P-wave negative phase in lead V1 were measured using an electrocardiogram, and PTFV1 was calculated. The peak filling rate (PFR) and one-third mean filling rate (1/3 MFR) were obtained as LV diastolic parameters using gated SPECT.PTFV1 showed a weak correlation with the LA volume index (r = 0.31; P < 0.001). Significant associations were observed between PTFV1 and PFR (r = -0.27; P < 0.001) and 1/3 MFR (r = -0.26; P = 0.001). A multivariate linear regression analysis showed that age (β = -0.26; P < 0.001), LV end-diastolic volume index (β = -0.27; P = 0.001), and PTFV1 (β = -0.15; P = 0.036) were significant factors associated with PFR. Moreover, male gender (β = -0.16; P = 0.041), LV mass index (β = -0.17; P = 0.046), and PTFV1 (β = -0.17; P = 0.022) were significant factors associated with the 1/3 MFR.PTFV1 is associated with LV diastolic function, as derived from gated SPECT in patients with no significant perfusion abnormalities.