James A. Case

Electrocardiographically gated myocardial perfusion SPECT: Technical principles and quality control considerations

ConclusionGated SPECT studies provide important information about cardiac function that is independent of perfusion data. This is permitted by the generalization of the nongated SPECT study to sample the data temporally. The benefits of this approach are accompanied by new technical and clinical challenges related largely to interaction of varying rates of sinus rhythm and the response of the computer system. Identification of potential technical limitations is important, as is recognizing for which patients gated SPECT acquisition may not be suitable. These considerations should be part of a quality program to assure the highest quality of gated SPECT images and optimize the clinical utility of this important new method of acquiring SPECT images.

Outcome of medical versus invasive treatment strategies for non-high-risk ischemic heart disease

The purpose of this study was to evaluate the outcomes of medical management compared with invasive management for patients with mild or moderate ischemia (non-high-risk) on stress tomographic myocardial perfusion scintigraphy. Of the 1,352 non-high-risk patients, 116 (9%) subsequently were referred for coronary angiography within the first 30 days after the scan; 99 (85%) of this group also underwent early revascularization procedures. The remaining 1,236 patients (91%) with non-high-risk ischemia did not undergo early invasive management. Unadjusted actuarial 3-year rate of cardiac death or nonfatal infarction was significantly better estimated survival in the medically managed group (2%) compared with the invasively managed group (22%), p=0.0001. Subsequent coronary revascularization procedures during 3-year follow-up were less frequent in the medically managed group (4%) than in the invasively managed group (42%), p=0.0001. A multivariable analysis identified invasive management strategy (p=0.0001) as the only correlate of cardiac events during follow-up. In summary, this study showed that patients with non-high-risk ischemia on stress perfusion imaging can be treated safety with a conservative medical management strategy.

An introduction to attenuation correction

SummaryAttenuation correction techniques have demonstrated improved diagnostic accuracy and quality of myocardial perfusion SPECT images in limited studies. The future success of these methods relies largely on understanding the characteristics of the images and their interpretative meaning, as well as their limitations. It will be important to define the impact on patient management decisions, quantitation, laboratory efficiency, physician confidence, and communication of important findings. Advances in these areas will help position nuclear cardiology to compete with other imaging modalities. As this technology matures, the technologist has an essential role in ensuring efficient use of these techniques and maximizing the quality of this promising new way to image patients.

Taking the perfect nuclear image: Quality control, acquisition, and processing techniques for cardiac SPECT, PET, and hybrid imaging

Nuclear Cardiology for the past 40 years has distinguished itself in its ability to non-invasively assess regional myocardial blood flow and identify obstructive coronary disease. This has led to advances in managing the diagnosis, risk stratification, and prognostic assessment of cardiac patients. These advances have all been predicated on the collection of high quality nuclear image data. National and international professional societies have established guidelines for nuclear laboratories to maintain high quality nuclear cardiology services. In addition, laboratory accreditation has further advanced the goal of the establishing high quality standards for the provision of nuclear cardiology services. This article summarizes the principles of nuclear cardiology single photon emission computed tomography (SPECT) and positron emission tomography (PET) imaging and techniques for maintaining quality: from the calibration of imaging equipment to post processing techniques. It also will explore the quality considerations of newer technologies such as cadmium zinc telleride (CZT)-based SPECT systems and absolute blood flow measurement techniques using PET.

American Society of Nuclear Cardiology and Society of Nuclear Medicine and Molecular Imaging Joint Position Statement on the Clinical Indications for Myocardial Perfusion PET

Expert Content Reviewers: Frank M. Bengel MD, Daniel S. Berman MD, Dennis A. Calnon MD, Paolo Camici MD, James A. Case PhD, Manuel D. Cerqueira MD, Panithaya Chareonthaitawee MD, Robert A. deKemp PhD, Dominique Delbeke MD, PhD, Marcelo F. Di Carli MD, Sharmila Dorbala MD, James W. Fletcher MD, Henry Gewirtz MD, K. Lance Gould MD, PhD, Robert Gropler MD, PhD, Justin A. Lundbye MD, Jamshid Maddahi MD, Terrence Ruddy MD, Heinz R. Schelbert MD, PhD, Thomas H. Schindler MD, Leslee J. Shaw PhD, H. William Strauss MD, and Patrick White MPH

Variability in normal myocardial blood flow measurements: physiologic, methodologic, or protocol related?

The current issue of the Journal of Nuclear Cardiology includes an interesting investigation that studied 3 software approaches for quantitating myocardial blood flow (MBF) and MBF reserve (MBFR) in 49 subjects who met multiple criteria for having normal cardiovascular physiology: able to exercise to a high level without chest pain or ischemic end-points, no major risk factors, and normal rubidium-82 myocardial perfusion images. The study found that these important flow measurements in apparently normal subjects varied substantially according to age, gender, coronary territory, and software employed. The results raise legitimate questions about whether positron emission tomography (PET) derived flow quantitation is currently sufficiently mature for inclusion in clinical imaging reports that might influence subsequent patient care. Performance of radionuclide myocardial perfusion imaging (MPI) using PET has been engendering interest and significant volume growth over the past few years. PET has been shown to offer improved image quality, interpretive certainty, and accuracy compared to both traditionally performed and attenuation-corrected single photon emission computed tomography (SPECT) MPI. PET MPI is most commonly performed with rubidium-82, a tracer that decays rapidly due to its 75 seconds half-life. Attractive attributes include throughput efficiency (rest/stress studies can be completed in about 40 minutes), low radiation exposure, peak stress regional and global ventricular function comparisons against rest parameters, and flow measurements validated against a variety of different standards. A novel capability of PET is the ability to move beyond spatially relative image interpretation to patientcentric quantitation. In a spatially relative domain, abnormality is defined in one of 3 manners: one or two myocardial regions have less tracer uptake than a best and therefore presumed normal area; the left ventricle function deteriorates with stress (e.g., transient ischemic dilation, changes between rest and stress ejection fraction); or a non-perfusion marker such as lung uptake of Tl-201 or ischemic ECG changes alert to physiologically significant CAD not detected by perfusion defect analysis alone. PET’s patient-centric quantitation advances understanding about adequacy of MBF by providing an absolute measure of both global and regional blood flow at rest, at stress, and in relative terms as a ratio between stress and rest. As such, the truly unique contribution of PET is measurement of whether the myocardium is getting the blood flow necessary to meet needs, regardless of the basis for any limitation. Identified sites of blood flow compromise include the epicardial coronary arteries (local or diffuse stenoses, endothelial dysfunction/inflammation), the microcirculation, and increased epicardial-endocardial pressure gradients. These measurements have found value in improved risk stratification in varied patient populations, and for improved recognition of multi-vessel CAD. Two important questions arise in consideration of how PET flow measurements might fit into the testing paradigm for CAD. The first is a population-based concept; on a macro-level can MBF calculations help to inform about relative coronary circulation health and improve ability to risk-stratify patients? The second Reprint requests: Timothy M. Bateman, MD, Saint-Lukes Cardiovascular Consultants Mid America Heart Institute, Kansas City, MO; tbateman@saint-lukes.org J Nucl Cardiol 2015;22:85–8. 1071-3581/

PROSPECTIVE STUDY OF ULTRA-LOW DOSE STRESS-ONLY SOLID-STATE SPECT: COMPARISON OF EFFICIENCY, DOSIMETRY AND OUTCOMES VERSUS TRADITIONAL-DOSE ATTENUATION-CORRECTED STRESS-ONLY ANGER SPECT (NCT01373944)

34.00 Copyright 2014 American Society of Nuclear Cardiology.

Status of cardiovascular PET radiation exposure and strategies for reduction: An Information Statement from the Cardiovascular PET Task Force

Stress-only (SO) SPECT is increasingly being used in symptomatic low-intermediate risk patients in order to minimize ionizing radiation. We tested whether ultra-low dose Tc-99m sestamibi (MIBI) utilizing new CZT-SPECT instrumentation might be as effective as usual-dose MIBI using Anger cameras with

Proceedings of the ASNC cardiac PET summit meeting, May 12, 2014, Baltimore MD: 5. Advances in radiopharmaceutical availability and development of cardiac PET tracers

Cardiovascular positron emission tomography (PET) imaging provides high-quality visual and quantitative myocardial perfusion and function images. In addition, cardiovascular PET can assess myocardial viability, myocardial inflammatory disorders such as cardiac sarcoid, and infections of implanted devices including pacemakers, ventricular assist devices, and prosthetic heart valves. As with all nuclear cardiology procedures, the benefits need to be considered in relation to the risks of exposure to radiation. When performed properly, these assessments can be obtained while simultaneously minimizing radiation exposure. The purpose of this information statement is to present current concepts to minimize patient and staff radiation exposure while ensuring high image quality.

Contemporary Cardiac SPECT Imaging—Innovations and Best Practices: An Information Statement from the American Society of Nuclear Cardiology

The continued success of nuclear imaging and nuclear cardiology is dependent in part upon a steady availability of existing tracers as well as the development of new tracers to meet the evolving needs of the population it serves. Cardiac PET tracers have traditionally enjoyed advantages over SPECT tracers in terms of radiation exposure, image quality, and tracer kinetics, in particular, extraction fraction at high blood flow rates. This review reflects presentations made at the ASNC Cardiac PET Summit meeting, 12 May 2014 and will evaluate availability of commonly used PET radiopharmaceuticals now and in the future, as well as progress in development of new F-18 tracers for myocardial imaging.