Viewer, Techniques for generating attenuation map using cardiac SPECT emission data only: a systematic review, Microvascular Dysfunction and Clinical Outcomes, Myocardial perfusion assessed with cardiac computed tomography in women without coronary heart disease, Joint reconstruction of rest/stress myocardial perfusion SPECT, Attenuation correction in myocardial perfusion imaging affects the assessment of infarct size in women with previous inferior infarct, Coronary CT Angiography–derived Fractional Flow Reserve, Fast myocardial perfusion imaging with 99mTc in challenging patients using conventional SPECT cameras, Correction of hysteretic respiratory motion in SPECT myocardial perfusion imaging: Simulation and patient studies, Ionizing Radiation Impairs Endogenous Regeneration of Infarcted Heart: An Qualitative measurements, including Myocardial Mass, Myocardial Volume and Hounsfield Unit (HU) attenuation; Polar map plots (contrast, transmural perfusion ratio, perfusion index) highlighting potential myocardium defects; Defect scoring tool provides users an … For stress tests, 206 are labeled abnormal and 237 normal. Patients with apical hypertrophic cardiomyopathy (ACM) are often referred for myocardial perfusion single photon emission computed tomography (SPECT) as a result of marked T-wave inversion and chest pain syndromes. one based on Chebyshev polynomials and one based on Cayley polynomials, and a Fully Connected Network (FCN) as well as a Convolutional Neural Network (CNN) as baseline methods. Recently, Betancour et al.12 proposed a hybrid method based on deep convolutional neural networks which takes into account both raw and quantitative (based on TPD) polar maps for the prediction of obstructive stenosis. Diagnostic accuracy of myocardial perfusion imaging with czt technology: systemic review and meta-analysis of comparison with invasive coronary angiography. Figure 10 Attenuation-corrected resting myocardial perfusion images obtained with SPECT/CT show radiotracer activity in the bowel (arrow), a feature that masks the inferior wall defect evident on delayed images (arrowhead). arXiv preprint arXiv:1506.05163 (2015). An early example is the work of Slomka et al.9, who proposed a method based on intensity-based image registration and normalization in order to derive a relative count change measure, i.e. (a) Summary screen from a stress-only myocardial perfusion imaging examination performed with SPECT/CT shows small perfusion defects in the anterior and inferior walls (arrows) on images and maps obtained with the patient supine (Str [Sup]), and normal perfusion (arrowheads) on repeat images obtained with the patient prone (Str [Pr]). 99m In the presence of a motion artifact, the heart will be seen in different locations on adjacent SPECT projection images. Visual interpretation of the images is dependent on user experience, and thus quantitative data is also routinely incorporated into the evaluation as suggested by the American Society of Nuclear Cardiology (ASNC)2. Figure 11 Summary screen from an attenuation-corrected stress myocardial perfusion imaging examination (StrAC[1]) performed with SPECT/CT shows an extensive artifact in the inferior wall on images and polar maps. Polar maps are two-dimensional displays of the three-dimensional distribution of radiotracer activity in the left ventricle. This approach is more suited to the unstructured nature of polar maps. Levie, R., Monti, F., Bresson, X. Stress perfusion defects have been reported in ACM, but the characteristic SPECT pattern as well as the typical findings on volume-weighted polar maps has not been described. The carotid pulses, pulmonary function, and cardiac function should be evaluated, and the lungs should be assessed for evidence of heart failure and pulmonary edema. Figure 14 Summary screen from an attenuation-corrected stress (StrAC)-rest (RstAC) myocardial perfusion imaging examination performed with SPECT/CT in a patient with a left bundle branch block. The development of single photon emission computed tomography (SPECT) led to improved assessments of myocardial perfusion, and the use of electrocardiographic gating made accurate measurements of ventricular wall motion, ejection fractions, and ventricular volumes possible. 99m Figure 11 Summary screen from an attenuation-corrected stress myocardial perfusion imaging examination (StrAC[1]) performed with SPECT/CT shows an extensive artifact in the inferior wall on images and polar maps. 15, 6 July 2018 | Physics in Medicine & Biology, Vol. Apical thinning is more apparent on attenuation-corrected images and may be accentuated by the scatter correction and resolution recovery processes that are commonly incorporated in the reconstruction of attenuation-corrected images. In a related work, Asanjani et al.11 used even more inputs, i.e. Automatic quantification of myocardial perfusion stress–rest change: a new measure of ischemia. ACI = attenuation-corrected images, GSTRESS TC = ECG-gated stress imaging with a 99mTc-labeled tracer, HLA (INF → ANT) = horizontal long axis (inferior to anterior), SA = short axis, STRESS TC2 = delayed stress imaging after clearance of the radiotracer from abdominal organs, VLA (SEP → LAT) = vertical long axis (septum to lateral wall). Myocardial perfusion imaging traditionally has been performed with rest-stress imaging protocols based either on a 2-day examination schedule, with the maximum radiotracer dose administered for rest and stress perfusion studies performed on different days, or a 1-day examination schedule, with a low dose of the radiotracer administered for rest imaging and a higher dose administered for stress imaging. In addition, because the apex is closest to the detector, the spatial resolution of the normally thin apical segments of the left ventricle is greater than that of other segments. We repeated this process for all 17 segments and created a heatmap representation via assigning the respective classification score to all nodes with a segment. Viewer. Various attenuation correction methods have been used. http://creativecommons.org/licenses/by/4.0/, https://doi.org/10.1038/s41598-019-43951-8, Clinical quantitative cardiac imaging for the assessment of myocardial ischaemia, Application and Translation of Artificial Intelligence to Cardiovascular Imaging in Nuclear Medicine and Noncontrast CT, Quantitative clinical nuclear cardiology, part 2: Evolving/emerging applications, Classification models for SPECT myocardial perfusion imaging, Proposed Requirements for Cardiovascular Imaging-Related Machine Learning Evaluation (PRIME): A Checklist. Summed stress scores of less than 3 are considered normal, whereas scores of 4–7, 8–12, and 13 or higher are indicative of low, intermediate, and high risk for a hard cardiac event.Figure 7Download as PowerPointOpen in Image As proposed by Defferrad et al.20, filters are represented using Chebyshev polynomials: where \({T}_{k}(\tilde{{\rm{\Lambda }}})\in {{\mathbb{R}}}^{460\times 460}\) represents a Chebyshev polynomial of order k applied to a frequency \(\tilde{{\rm{\Lambda }}}\in [\,-\,\mathrm{1,1]}\). By submitting a comment you agree to abide by our Terms and Community Guidelines. This approach is comparable to previous related works5,6,7, but uses the full information of the polar map without sub-sampling or quantization of intensity values. The normal cases were identified in a three reader consensus decision from data acquired in 2014 and 2015. The maps provide a two-dimensional view of the entire three-dimensional left ventricular myocardium, which is segmented (blue radial lines) into the territories of the left anterior descending (LAD), left circumflex (LCX), and right coronary (RCA) arteries. Evaluation of the sinogram for discontinuities may be especially useful for detecting movement. Deep learning for prediction of obstructive disease from fast myocardial perfusion spect. 1b, convolutions can be generalized to arbitrary arrangements of data and the MPI-derived polar maps can be directly fed to convolutional neural networks, that are based on these generalized convolution operations. The readers had access only to the polar maps and were blinded to any other information. 33, No. This way, it asserts that these points belong to the cardiac muscle [2]. However, the latter task is not the main goal of this work and thus only evaluated on 30 polar maps. Unlike the traditional approaches, our algorithm is automatic. & Vandergheynst, P. Convolutional neural networks on graphs with fast localized spectral filtering. J. Nucl. 7, © 2021 Radiological Society of North America, Normal stress-only versus standard stress/rest myocardial perfusion imaging: similar patient mortality with reduced radiation exposure, The prognosis of a normal stress-only Tc-99m myocardial perfusion imaging study, Regadenoson, a selective A2A adenosine receptor agonist, causes dose-dependent increases in coronary blood flow velocity in humans, Novel short-acting A2A adenosine receptor agonists for coronary vasodilation: inverse relationship between affinity and duration of action of A2A agonists, Safety of regadenoson, a selective adenosine A2A agonist, in patients with chronic obstructive pulmonary disease: a randomized, double-blind, placebo-controlled trial (RegCOPD trial), Safety of regadenoson, an adenosine A2A receptor agonist for myocardial perfusion imaging, in mild asthma and moderate asthma patients: a randomized, double-blind, placebo-controlled trial, A multicenter, double-blind, randomized, placebo-controlled study of the safety and tolerance of regadenoson in patients with renal impairment, Current advances in vasodilator pharmacological stress perfusion imaging, Treadmill exercise during adenosine infusion is safe, results in fewer adverse reactions, and improves myocardial perfusion image quality, Impact of limited treadmill exercise on adenosine Tc-99m sestamibi single-photon emission computed tomographic myocardial perfusion imaging in coronary artery disease, Impact of an abbreviated adenosine protocol incorporating adjunctive treadmill exercise on adverse effects and image quality in patients undergoing stress myocardial perfusion imaging, The impact of adjunctive adenosine infusion during exercise myocardial perfusion imaging: results of the Both Exercise and Adenosine Stress Test (BEAST) trial, Single-photon emission computed tomography artifacts, Clinical review of attenuation-corrected cardiac SPECT, Improved outcome prediction by SPECT myocardial perfusion imaging after CT attenuation correction, Myocardial perfusion and function single photon emission computed tomography, Clinical validation of SPECT attenuation correction using x-ray computed tomography–derived attenuation maps: multicenter clinical trial with angiographic correlation, Artifacts and pitfalls in myocardial perfusion imaging, Combined supine and prone quantitative myocardial perfusion SPECT: method development and clinical validation in patients with no known coronary artery disease, Combined quantitative supine-prone myocardial perfusion SPECT improves detection of coronary artery disease and normalcy rates in women, Exercise supplementation to dipyridamole prevents hypotension, improves electrocardiogram sensitivity, and increases heart-to-liver activity ratio on Tc-99m sestamibi imaging, Attenuation correction in myocardial perfusion SPECT/CT: effects of misregistration and value of reregistration, Directions and magnitudes of misregistration of CT attenuation-corrected myocardial perfusion studies: incidence, impact on image quality, and guidance for reregistration, Left bundle-branch block artifact on single photon emission computed tomography with technetium Tc 99m (Tc-99m) agents: mechanisms and a method to decrease false-positive interpretations, Procedure guidelines for radionuclide myocardial perfusion imaging, Open in Image We aimed to explore the feasibility of integrative quantitative representation of LV perfusion, function and viability in adjacent polar plots. contributed to manual labeling of the dataset. 8, International Journal of Radiation Oncology*Biology*Physics, Vol. From the Division of Nuclear Medicine, Department of Radiology, University of Michigan Health System, 1500 E Medical Center Dr, B1 G505 UH, Ann Arbor, MI 48109-5028. Background: The clinical management of patients with coronary artery disease (CAD) often involves a complex assessment of the extent and severity of changes in left ventricular (LV) myocardial perfusion, function and viability. A symmetric 15% energy window is centered at 140 keV, the photopeak energy of 99mTc sestamibi. Our method could thus assist the decision-making process of physicians when analyzing polar map data obtained from myocardial perfusion images. Quantitative analysis of myocardial perfusion images ... creating a bull’s-eye map or polar maps. The main goal of this study is to investigate whether, and the extent to which, the knowledge of an expert reader assessing these polar maps can be acquired by such networks. However, attenuation correction itself may introduce artifacts if the anatomic and scintigraphic images are misregistered in the process. A coarser localization, performed on a “per vessel“ basis, reflects the analysis clinicians would normally perform. We address this problem by representing the polar map as an undirected graph and performing convolutional operations in the spectral domain. Furthermore, areas relevant for the classification decision can be directly visualized on the polar map data using standard attribution techniques16 as shown in Fig. Max-pooling of sizes 4 and 2 were used for the first and second layer respectively. Accurate interpretation of SPECT/CT myocardial perfusion imaging studies requires both a working knowledge of potential abnormalities and a thorough understanding of the artifacts that can occur in image data acquisition and processing. Over polar images, slice data provided inconsistent—and if present minor—benefits in terms of uncertainty (decrease only for physician 1, increasing uncertainty for physician 3). Nondairy and noncaffeinated beverages may be consumed up to the time of imaging, but patients are instructed not to ingest caffeine for 12–24 hours before the imaging examination, because caffeine can blunt the effect of commonly used pharmacologic stress induction agents. Patients with moderate to severe bronchospasm at the time of the perfusion imaging study may require inhalation therapy with albuterol sulfate or a similar medication to minimize wheezing before the regadenoson infusion is administered (7). 36, No. Cite this article. CAS  4, Nuclear Medicine Communications, Vol. After a delay, the duration of which depends on the stress induction protocol (15 minutes with exercise, 45–60 minutes with the use of a pharmacologic agent), the patient undergoes electrocardiography (ECG)-gated myocardial perfusion imaging with a SPECT/CT system (Symbia T16 Truepoint; Siemens, Hoffman Estates, Ill]). Our CNN architecture employs only 2 layers of convolutional filters with a kernel size of 5 × 5 in the first layer and 3 × 3 in the second. At the authors’ institution, all patients referred for myocardial perfusion imaging complete a focused cardiovascular history survey and undergo a physical examination immediately before imaging. Factors such as patient motion and improper alignment of the raw SPECT and CT image datasets can lead to propagation of artifacts on the final images. 4, No. Defferrard, M., Bresson, X. S.N. Using a threshold to match the specificity of TPD, per-patient sensitivity has been reported to improve from 79.8% (TPD) to 82.3% (p < 0.05), and per-vessel sensitivity to improve from 64.4% (TPD) to 69.8% (p < 0.01). Arsanjani, R. et al. Classification of Polar Maps from Cardiac Perfusion Imaging with Graph-Convolutional Neural Networks, \({\mathscr{G}}=({\mathscr{V}},\, {\mathcal E} ,\,A)\), \(A\in {{\boldsymbol{{\mathbb{R}}}}}^{460\times 460}\), \({\rm{\Lambda }}\in {{\mathbb{R}}}^{460\times 460}\), \(x\,\ast \,z=U{g}_{\theta }({\rm{\Lambda }}){U}^{T}x\), $${g}_{\theta }({\rm{\Lambda }})=\sum _{k=0}^{K-1}\,{\theta }_{k}{T}_{k}(\tilde{{\rm{\Lambda }}}),$$, \({T}_{k}(\tilde{{\rm{\Lambda }}})\in {{\mathbb{R}}}^{460\times 460}\), \(\tilde{{\rm{\Lambda }}}\in [\,-\,\mathrm{1,1]}\), $${g}_{c,h}({\rm{\Lambda }})={c}_{0}+2Re\{\sum _{k=1}^{K}\,{c}_{k}{(h{\rm{\Lambda }}-i)}^{k}{(h{\rm{\Lambda }}+i)}^{-k}\},$$, \({\bf{c}}=({c}_{0},\,\mathrm{...,}\,{c}_{K})\). The dataset consists of 946 labeled polar maps, 503 of which are rest tests and the remaining stress tests. The diagnostic accuracy of the classifier in the latter study has been shown to be on par or slightly better than the one achieved by two participating experts, respectively11. (a, b) Summary screens from an attenuation-corrected stress (StrAC)-rest (RstAC) myocardial perfusion imaging examination performed with SPECT/CT in a patient with chest pain. (2020), Seminars in Nuclear Medicine Myocardial perfusion imaging is a non-invasive imaging technique commonly used for the diagnosis of Coronary Artery Disease and is based on the injection of radiopharmaceutical tracers into the blood stream. The network ends with a fully-connected layer with a softmax, cf. In the Polar Plot slide pictured above, polar maps of two patients are arranged vertically on either side of the segmentation guide. The patient is positioned supine on the table with his or her arms raised straight above the head and a nylon belt wrapped snugly around the abdomen to minimize respiratory motion. Apparent perfusion defects resulting from apical thinning are best seen on vertical and horizontal long-axis cardiac images and polar map displays (Fig 15). The proposed model achieves an agreement with the human observer on 89.3% of rest test polar maps and on 91.1% of stress test polar maps. 10, Nuclear Medicine Communications, Vol. 88, No. Google Scholar. The cardiac chamber size, left ventricular wall motion, and right ventricular perfusion and wall motion should be reported. We assessed the ability to localize the presence of CAD on a 17-segment division and on a coarse 3-segment division which is based on coronary artery blood supply to the finer segments as shown in Fig. Infarcted fraction in a segment and its relative level observed in the numerical model. For assessing localization performance, the model that agreed best with the human observer, i.e. The contrast recovery ratio was also calculated to quantify the ability to classify the polar maps with and without the MP defect. In Advances in Neural Information Processing Systems, 3844–3852 (2016). Here, a polar map is represented as a graph \({\mathscr{G}}=({\mathscr{V}},\, {\mathcal E} ,\,A)\) where \({\mathscr{V}}\) is the set of 460 vertices, \( {\mathcal E} \) is the set of edges and \(A\in {{\boldsymbol{{\mathbb{R}}}}}^{460\times 460}\) is the adjacency matrix representing the weight of each edge. However, it is best left to the referring physician to determine whether the patient can tolerate the withholding of these medications. Assessment of imaging data is commonly performed by visual inspection of polar maps … 5). Sci Rep 9, 7569 (2019). (c) Anatomical division showing to which major vessel bed each myocardial segment is assigned to. Such findings emphasize the importance of a careful review of the CT attenuation map and verification of its accurate coregistration with the SPECT images (Fig 13). A Rectified Linear Unit (ReLU) activation function is used for the neurons in the hidden layer and a softmax activation function is used for the output layer. A comparison was also done of GSPET processing by polar map and beating cross-section methods in the diagnosis of perfusion disturbances. 1c. Summed stress scores of less than 3 are considered normal, whereas scores of 4–7, 8–12, and 13 or higher are indicative of low, intermediate, and high risk for a hard cardiac event. The approach has been developed using data from 1,638 patients. Automated interpretation of planar thallium-201-dipyridamole stress-redistribution scintigrams using artificial neural networks. Furthermore, another very likely reason for this finding could be the camera itself. Enter your email address below and we will send you your username, If the address matches an existing account you will receive an email with instructions to retrieve your username. Baseline methods are trained in mini batches of 64 samples for 70 epochs. Assessment of imaging data is commonly performed by visual inspection of polar maps showing the tracer uptake in a compact, two-dimensional representation of the left ventricle.