Hotspot quantification of myocardial focal tracer uptake from molecular targeted SPECT/CT images: experimental validation

Liu, Yi Hwa; Sahul, Zakir; Weyman, C.; Ryder, William J.; Dione, Donald P.; Dobrucki, Lawrence W.; Mekkaoui, Choukri; Brennan, Matthew P.; Hu, Xiaoyue; Hawley, Christi; Sinusas, Albert J.

doi:10.1117/12.768985

Cited by 4 publications

(6 citation statements)

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“…As such, prior information for true cardiac activity (not contaminated by the extracardiac organ) can be obtained from the anterior regions of the LV. Our algorithm (7) for the extracardiac activity correction is in part derived from these observations, and derivations of this algorithm are described in the supplemental data.…”

Section: Methodsmentioning

confidence: 99%

“…Accurate and reproducible quantitative assessments of these molecular processes present another challenge because quantification of the target radiotracer within the myocardium is inevitably complicated by the heterogeneous background and extracardiac radioactivity adjacent to the heart, which causes errors in the estimation of myocardial tracer uptake. Recently, our group has focused on the detection, characterization, and measurement of focal myocardial tracer uptake using a dual-isotope SPECT imaging protocol with targeted 99m Tc-labeled hot spot and 201 Tl perfusion agents (6,7). We reported previously the first, to our knowledge, hot spot SPECT quantification approach (6) for assessing tracer uptake in the myocardium.…”

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confidence: 99%

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Accuracy and Reproducibility of Absolute Quantification of Myocardial Focal Tracer Uptake from Molecularly Targeted SPECT/CT: A Canine Validation

Liu¹,

Sahul²,

Weyman³

et al. 2011

J Nucl Med

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Accurate and reproducible SPECT quantification of myocardial molecular processes remains a challenge because of the complication of heterogeneous background and extracardiac activity adjacent to the heart, which causes errors in the estimation of myocardial focal tracer uptake. Our aim in this study was to introduce a heuristic method for the correction of extracardiac activity into SPECT quantification and validate the modified quantification method for accuracy and reproducibility using a canine model. Methods Dual-isotope–targeted 99mTc and 201Tl perfusion SPECT images were acquired using a hybrid SPECT/CT camera in 6 dogs at 2 wk after myocardial infarction. Images were reconstructed with and without CT-based attenuation correction, and the reconstructed SPECT images were filtered and quantified simultaneously with incorporation of extracardiac radioactivity correction, gaussian fitting, and total-count sampling. Absolute myocardial focal tracer uptake was quantified from SPECT images using 3 different normal limits (maximum entropy [ME], mean-squared-error minimization [MSEM], and global minimum [GM]). SPECT-quantified percentage injected dose (%ID) was calculated and compared with the well-counted radioactivity measured from the postmortem myocardial tissue. SPECT quantitative processing was performed by 2 different individuals with extensive experience in cardiac image processing, to assess reproducibility of the quantitative analysis. Results Correlations between SPECT-quantified and well-counted %IDs using 3 different normal limits were excellent (ME: r = 0.82, y = 0.932x − 0.0102; MSEM: r = 0.73, y = 1.1413x − 0.0052; and GM: r = 0.7, y = 1.2147x − 0.0002). SPECT quantification using ME normal limits resulted in an underestimation of %ID, as compared with well-counted %ID. Myocardial focal tracer uptake quantified from SPECT images without CT-based attenuation correction was significantly lower than that with the attenuation correction. The %IDs quantified from attenuation-corrected SPECT images using MSEM and GM normal limits were not significantly different from well-counted %IDs. Reproducibility of the SPECT quantitative analysis was excellent (ME: r = 0.98, y = 0.9221x + 0.0001; MSEM: r = 0.97, y = 0.9357x + 0.0004; and GM: r = 0.96, y = 0.9026x + 0.001). Conclusion Our SPECT/CT quantification algorithm for the assessment of regional radioactivity may allow for accurate and reproducible serial noninvasive evaluation of molecularly targeted tracers in the myocardium.

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Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

Accuracy and Reproducibility of Absolute Quantification of Myocardial Focal Tracer Uptake from Molecularly Targeted SPECT/CT: A Canine Validation

Liu¹,

Sahul²,

Weyman³

et al. 2011

J Nucl Med

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“…74 The clinical feasibility of this imaging approach was confirmed in more clinically relevant canine and porcine models of post infarction remodeling. 75 Thrombinactivated FXIII also has an important role in postinfarction remodeling, and the prevention of ventri cular dilation and cardiac rupture after MI. 76 The feasibility of targeted SPECT imaging of FXIII with 111 InDOTA FXIII has been demonstrated in animal imaging studies; 111 InDOTAFXIII was found to be crosslinked to extra cellular proteins and preferentially accumulated in areas of increased FXIII activity.…”

Section: Neuroreceptor Imagingmentioning

confidence: 99%

PET and SPECT in cardiovascular molecular imaging

2009

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The current focus of cardiovascular medicine is on early detection and prevention of disease, to control the escalating costs of health care. To achieve this goal, novel imaging approaches that allow for early detection of disease and risk stratification are needed. Traditionally, the diagnosis, monitoring, and prognostication of cardiovascular disease were based on techniques that measured changes in metabolism, blood flow, and biological function. Molecular imaging is emerging as a new tool for the noninvasive detection of biological processes that can differentiate and characterize tissues before manifestation of gross anatomical features or physiological consequences. Leading the way are techniques involving high-sensitivity radiotracers that could revolutionize current diagnostic paradigms. This Review provides an overview of selected molecular-based single photon emission CT (SPECT) and PET imaging strategies for the evaluation of cardiovascular disease-including the evaluation of myocardial metabolism and neurohumoral activity of the heart-and potential future targeted methods of evaluating critical molecular processes, such as atherosclerosis, ventricular remodeling after myocardial infarction, and ischemia-associated angiogenesis.

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“…These investigators have developed image-analysis tools to quantify regional 99m Tc-RP805 from in vivo dual-isotope hybrid SPECT/CT images to track serial changes in MMP activation (Fig. 2) (11,12). These dual-isotope imaging studies suggest that MMP activation is taking place within the sites of injury and remotely and support the concept that molecules that target MMP activation might be used to evaluate ventricular remodeling.…”

Section: Radiotracer Imaging For Prediction Of Postinfarction LV Remomentioning

confidence: 99%

Multimodality Imaging of Myocardial Injury and Remodeling

Kramer¹,

Sinusas²,

Sosnovik

et al. 2010

J Nucl Med

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Advances in cardiovascular molecular imaging have come at a rapid pace over the last several years. Multiple approaches have been taken to better understand the structural, molecular, and cellular events that underlie the progression from myocardial injury to myocardial infarction (MI) and, ultimately, to congestive heart failure. Multimodality molecular imaging including SPECT, PET, cardiac MRI, and optical approaches is offering new insights into the pathophysiology of MI and left ventricular remodeling in small-animal models. Targets that are being probed include, among others, angiotensin receptors, matrix metalloproteinases, integrins, apoptosis, macrophages, and sympathetic innervation. It is only a matter of time before these advances are applied in the clinical setting to improve post-MI prognostication and identify appropriate therapies in patients to prevent the onset of congestive heart failure.

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Hotspot quantification of myocardial focal tracer uptake from molecular targeted SPECT/CT images: experimental validation

Cited by 4 publications

References 4 publications

Accuracy and Reproducibility of Absolute Quantification of Myocardial Focal Tracer Uptake from Molecularly Targeted SPECT/CT: A Canine Validation

Accuracy and Reproducibility of Absolute Quantification of Myocardial Focal Tracer Uptake from Molecularly Targeted SPECT/CT: A Canine Validation

PET and SPECT in cardiovascular molecular imaging

Multimodality Imaging of Myocardial Injury and Remodeling

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