Diagnostic and prognostic significance of ischemic electrocardiographic changes with regadenoson-stress myocardial perfusion imaging.

BACKGROUND: The diagnostic and prognostic value of regadenoson-induced ST-segment depression (ST↓) is not defined. Due to the low incidence of ST↓ ≥1.0 mm with vasodilator stress, a lower threshold to define ischemic ECG response may provide improved clinical utility. METHODS: We conducted a retrospective cohort study of patients who underwent regadenoson-stress SPECT myocardial perfusion imaging (MPI) followed by coronary angiography within 6 months. Ischemic ST↓ was defined as ≥0.5 mm. The prevalence of angiographically severe coronary artery disease (CAD) and the rates of major adverse cardiac events (MACE) including cardiac death, myocardial infarction, and coronary revascularization were determined. RESULTS: In a diagnostic cohort of 629 subjects, 117 (18.6%) had ST↓ ≥0.5 mm. Severe CAD was more prevalent in the ST↓ ≥0.5 vs ST <0.5 group (13.7% vs 5.3%, P = .001). Among patients with normal MPI (n = 229), the prevalence of severe CAD was higher in the ST↓ ≥0.5 group (8.2% vs 2.2%, P = .04). Adjusting for clinical and imaging covariates, ST↓ ≥0.5 mm was independently predictive of severe CAD [odds ratio = 3.37, 95% confidence interval (CI) = 1.67-6.83, P = .001], and provided incremental diagnostic value (Chi square increment = 10.3, P = .001). In an outcome cohort of 748 subjects, after adjusting for clinical and imaging covariates, ST↓ ≥0.5 mm was associated with increased MACE rate in the entire cohort [hazard ratio = 1.41, CI 1.01-1.96, P = .04] and in the subgroup of patients with normal MPI [hazard ratio = 2.2, CI 1.11-4.39, P = .02], and provided incremental prognostic value (Chi square increment = 3.9, P = .049). A diagnostic ST↓ threshold of 0.5 mm provided greater discriminatory capacity than a 1.0 mm cutoff (P = .03). CONCLUSIONS: Among patients selected to undergo coronary angiography, regadenoson-induced ST↓ ≥0.5 mm was associated with higher rates of severe CAD and MACE, irrespective of MPI finding.

Soft tissue attenuation patterns in stress myocardial perfusion SPECT images: a comparison between supine and upright acquisition systems.

BACKGROUND: Soft tissue attenuation patterns and their interaction with body habitus and gender in Single Photon Emission Computed Tomography (SPECT)-myocardial perfusion imaging (MPI) of upright patient-position acquisition systems are not well described. METHODS: In a retrospective cross-sectional study, we compared the prevalence and patterns of soft tissue attenuation in two groups of normal SPECT-MPI studies acquired by supine (n = 263) vs upright (n = 212) acquisition systems. RESULTS: Attenuation patterns observed in the study population were: anterior (22.3%), inferior (51.6%) and lateral (18.1%). Anterior attenuation was significantly less in those imaged upright (6.1% vs 35.4%), P < .001; particularly among women (9.5% vs 50.7%), P < .001. Inferior attenuation was more common among women imaged upright (49.5% vs 13.5%), P < .001; but was not affected by imaging position among men. Lateral attenuation was more prevalent in the upright group (24.1% vs 13.3%), P = .002; and had a strong association with female gender (P < .001) and BMI ≥ 30 (P < .001). CONCLUSIONS: Upright SPECT-MPI acquisition is associated with a unique attenuation pattern which is vastly different than the supine position. Female gender strongly impacted this attenuation pattern, particularly obese women. Our study is the first to describe, in details, the attenuation patterns with upright imaging and is critical for the accurate interpretation of SPECT-MPI acquired with upright systems.

Soft Tissue Attenuation Patterns Associated with Upright Acquisition SPECT Myocardial Perfusion Imaging: A Descriptive Study.

BACKGROUND: Little is known about soft tissue attenuation artifacts when an upright patient-position SPECTmyocardial perfusion imaging (MPI) system is used. In this investigation we sought to describe the patterns and frequency of attenuation artifacts associated with this type of instruments and we explored the impact of gender and body habitus on these artifacts. METHODS: In a cross-sectional study, we described the prevalence of various soft-tissue attenuation patterns in 212 normal SPECT-MPI studies acquired with an upright patient-position imaging system. RESULTS: In these 212 normal, clinically-indicated, upright-acquisition SPECT-MPIs the attenuation patterns observed were: anterior (6.1%), inferior (63.7%) and lateral (24.1%). Though uncommon, anterior attenuation trended to being more prevalent among women [9.5% vs. 3.4%, P=0.07] and was independently associated with chest circumference. Lateral attenuation was more common among women [34.7% vs. 15.4%, p=0.001] and was strongly associated with obesity (p<0.001). Inferior attenuation was more prevalent among men than women (75.2% vs. 49.5% respectively, P<0.001). CONCLUSIONS: Soft-tissue attenuation artifacts are common in upright-acquisition SPECT-MPI. Recognizing the frequency of these attenuation patterns and their interaction with gender and body habitus is critical for the accurate interpretation of SPECT-MPI.

Soft Tissue Attenuation Patterns Associated with Supine Acquisition SPECT Myocardial Perfusion Imaging: A Descriptive Study.

PURPOSE: Soft-tissue attenuation patterns in SPECT-myocardial perfusion imaging (MPI) of supine acquisition systems are well recognized. Their prevalence and interaction with body-habitus and gender are ill-defined, which we sought to describe in this study. METHODS: In a cross-sectional study, we described the prevalence of soft-tissue attenuation patterns in normal SPECT-MPI studies acquired with a supine patient-position SPECT system. RESULTS: In 263 normal, clinically-indicated, supine-acquisition SPECT-MPIs the attenuation patterns observed were: anterior (35.4%), inferior (41.8%) and lateral (13.3%). Anterior attenuation was more prevalent among women (50.7% vs. 15.7%, P<0.001) and was associated with chest circumference among men. Conversely, inferior attenuation was more prevalent among men (78.3% vs. 13.5%, P<0.001) and was not affected by body-habitus. Lateral attenuation was more common among women (19.6% vs. 5.2%, p=0.001) and was associated with obesity (p=0.015). CONCLUSIONS: Soft-tissue attenuation artifacts are common in supine-acquisition SPECT-MPI. The recognition of their prevalence and association with body-habitus and gender is critical for the accurate interpretation of SPECT-MPI.