Challenges of gated myocardial perfusion SPECT processing

The paper provides an in-depth look at gated myocardial perfusion single photon emission computed tomography (SPECT) data processing. Attention paid to several unmentioned subjects of the quantitative analysis of gated myocardial perfusion SPECT data. The article considers several options in the construction process of the ellipsoid coordinate system of the left ventricle (LV). Mathematical representation of polar maps is given. Formulas of the regional parameters calculation are proposed. Issues of phase analysis are explored.

TECHNETIUM-99M MIBI GATED MYOCARDIAL PERFUSION SINGLE PHOTON EMISSION COMPUTED TOMOGRAPHY IMAGING – VALIDATION OF STRESS ONLY PROTOCOL

Objective: To validate ‘stress only’ protocol against ‘rest stress protocol in normal and essentially normal cases undergoing Tc99m MIBI gated myocardial perfusion Single Photon Emission Computed Tomography imaging. Study Design: A retrospective observational study. Place and Duration of Study: Department of Nuclear Cardiology, Armed Forces Institute of Cardiology/National Institute of Heart Disease, Rawalpindi, Pakistan, from Jul to Sep 2019. Methodology: 136 cases were included. Patients underwent Tc-99m gated Single Photon Emission Computed Tomography MPI using a single day, rest/stress protocol. The rest study was performed first with 8-10 mCi Tc-99m MIBI followed by stress study, 3 hours later with 3 times the rest dose. The most common stress technique was pharmacological stress and bicycle ergometer exercise with 0.14 mg/kg/min adenosine infusion. Few patients underwent physical stress using Bruce protocol, achieving a minimum of 85% of the target heart rate. Mages–stress followed by rest–were evaluated by two experienced nuclear cardiologists (blinded to the MPI reports) and interpreted as ‘normal’ or ‘essentially normal’. Results: Evaluation of stress-only and rest-stress Single Photon Emission Computed Tomography myocardial images yielded a concordance rate of 84.56% with Cohen’s kappa coefficient of 0.69. Conclusion: Substantial agreement and good concordance were found in normal and essentially normal ‘stress only’ and ‘rest stress protocols.

Short-duration, submaximal intensity exercise stress combined with adenosine triphosphate decreases artifacts in myocardial perfusion single-photon emission computed tomography

Background Myocardial perfusion single-photon emission computed tomography (SPECT) imaging with stress is a useful examination for detecting coronary artery disease. Since the presence of artifacts is remaining challenges, we aimed to define the minimum intensity of low-grade exercise stress levels combined with drug stress to reduce undesired artifacts and their related factors. Methods We divided patients with suspicious coronary artery disease into 4 groups as follows: group A, adenosine triphosphate (ATP) for 6 min; group A + 25 W, ATP + 25 W exercise for 6 min; group A + 35 W, ATP + 35 W exercise for 6 min; group A + 45 W, ATP + 45 W exercise for 6 min) and enrolled only those whose summed stress scores were < 3. Undesired artifacts were evaluated on the basis of heart-to-liver activity (H/L) ratio and heart-to-10 pixels below the heart (H/below the H) ratio. Results The logarithmic values of H/L and H/below the H ratios were significantly higher in groups A + 35 W and A + 45 W than in group A (p < 0.05, each). In all the patients, the logarithmic values of H/L and H/below the H ratios positively correlated with the increment of rate pressure product (RPP, p = 0.002 and p = 0.005, respectively) after stress in the univariate analysis. The left ventricular end-diastolic volume (LVEDV) after stress (p = 0.002) negatively correlated with the logarithmic value of H/below the H ratio, but not H/L ratio. Although the increment of RPP was independently associated with the logarithmic values of both H/L (p = 0.001) and H/below the H ratios (p = 0.005), LVEDV was also independently associated with the logarithmic value of H/below the H ratio (p < 0.001) in multivariate regression analysis under adjusting with age and sex. Conclusion ATP plus ≥35 W exercise stress for 6 min was useful for reducing undesired artifacts after stress in myocardial perfusion SPECT. LVEDV after stress in addition to the increment of RPP was independently associated with the H/below the H ratio, but not the H/L ratio.

Short-duration, submaximal intensity exercise stress combined with adenosine triphosphate decreases artifacts in myocardial perfusion single-photon emission computed tomography

Background: Myocardial perfusion single-photon emission computed tomography (SPECT) imaging with stress is a useful examination for detecting coronary artery disease. Since the presence of artifacts is remaining challenges, we aimed to define the minimum intensity of low-grade exercise stress levels combined with drug stress to reduce undesired artifacts and their related factors.Methods: We divided patients with suspicious coronary artery disease into 4 groups as follows: group A, adenosine triphosphate (ATP) for 6 min; group A+25 W, ATP+25 W exercise for 6 min; group A+35 W, ATP+35 W exercise for 6 min; group A+45 W, ATP+45 W exercise for 6 min) and enrolled only those whose summed stress scores were <3. Undesired artifacts were evaluated on the basis of heart-to-liver activity (H/L) ratio and heart-to-10 pixels below the heart (H/below the H) ratio. Results: The logarithmic values of H/L and H/below the H ratios were significantly higher in groups A+35 W and A+45 W than in group A (p<0.05, each). In all the patients, the logarithmic values of H/L and H/below the H ratios positively correlated with the increment of rate pressure product (RPP, p=0.002 and p=0.005, respectively) after stress in the univariate analysis. The left ventricular end-diastolic volume (LVEDV) after stress (p=0.002) negatively correlated with the logarithmic value of H/below the H ratio, but not H/L ratio. Although the increment of RPP was independently associated with the logarithmic values of both H/L (p=0.001) and H/below the H ratios (p=0.005), LVEDV was also independently associated with the logarithmic value of H/below the H ratio (p<0.001) in multivariate regression analysis under adjusting with age and sex.Conclusion: ATP plus ≥35 W exercise stress for 6 min was useful for reducing undesired artifacts after stress in myocardial perfusion SPECT. LVEDV after stress in addition to the increment of RPP was independently associated with the H/below the H ratio, but not the H/L ratio.