Clinical value of supine and upright myocardial perfusion imaging in obese patients using the D-SPECT camera

Accurate and efficient rapid acquisition early post-injection stress-first CZT SPECT myocardial perfusion imaging with tetrofosmin and attenuation correction

INTRODUCTION

Myocardial perfusion imaging (MPI) protocols have not changed significantly despite advances in instrumentation and software. We compared an early post-injection, stress-first SPECT protocol to standard delayed imaging.

METHODS

95 patients referred for SPECT MPI were imaged upright and supine on a Spectrum Dynamics D-SPECT CZT system with CT attenuation correction. Patients received injection of 99mTc tetrofosmin at peak of regadenoson stress and were imaged. Early post-stress (mean 17 ± 2 minutes) and Standard 1-h delay (mean 61 ± 13 min). Three blinded readers evaluated images for overall interpretation, perceived need for rest imaging, image quality, and reader confidence. Laboratory efficiency was also evaluated.

RESULTS

Blinded readers had the same response for the need for rest in 77.9% of studies. Studies also had the same interpretation in 89.5% of studies. Reader confidence was high (86.0% (Early) and 90.3% (Standard p = 0.52. Image quality was good or excellent in 87.4% Early vs 96.8% Standard (p = 0.09). Time between patient check-in and end of stress imaging was 104 ± (Standard) to 60 ± 18 minutes (Early) (p < 0.001).

CONCLUSION

Early post-injection stress-only imaging using CZT SPECT/CT appears promising with Tc-99m tetrofosmin with similar image quality, reader confidence, diagnosis, and need for a rest scan.

Diagnostic performance of different cardiac stress protocols for myocardial perfusion imaging for the diagnosis of coronary artery disease using a cadmium-zinc-telluride camera with invasive coronary angiography correlation

PURPOSE

To evaluate the diagnostic performance of three different cardiac stress protocols for myocardial perfusion imaging (MPI) using a cadmium-zinc-telluride (CZT) camera with invasive coronary angiography (ICA) correlation for the diagnosis of coronary artery disease in a high risk population.

METHODS

Retrospective study of 263 patients (96 women and 167 males, mean age 68 years) from which 119 patients performed a bicycle stress test (BST), 113 pharmacological stress test (PST) and 31 a combination of the two (CST) between September 2014 and December 2018. The patients then underwent myocardial perfusion imaging (MPI), followed by ICA and evaluated by means of quantitative angiography software, within six months after the MPI. The mean pre-test probability score for coronary disease according to the European Society of Cardiology criteria was 36% for the whole population. The MPI was performed in a dedicated CZT cardio camera (D-SPECT Spectrum Dynamics) with a two-day protocol, according to the European Association of Nuclear Medicine guidelines.

RESULTS

No significant difference was observed between the three stress protocols in terms of diagnostic accuracy (BST 85%, PST 88%, CST 84%). The overall diagnostic accuracy of MPI to identify patients with any obstructive CAD at ICA was 86%, Sensitivity 93%, Specificity 54%, PPV 90% and NPV 63%.

CONCLUSION

The CZT D-SPECT camera achieves overall satisfactory results in the diagnosis of CAD, observing no significant differences in the diagnostic performance when the stress test was performed as a BST, PST or CST.

Deep learning prediction of quantitative coronary angiography values using myocardial perfusion images with a CZT camera

PURPOSE

Evaluate the prediction of quantitative coronary angiography (QCA) values from MPI, by means of deep learning.

METHODS

546 patients (67% men) undergoing stress 99mTc-tetrofosmin MPI in a CZT camera in the upright and supine position were included (1092 MPIs). Patients were divided into two groups: ICA group included 271 patients who performed an ICA within 6 months of MPI and a control group with 275 patients with low pre-test probability for CAD and a normal MPI. QCA analyses were performed using radiologic software and verified by an expert reader. Left ventricular myocardium was segmented using clinical nuclear cardiology software and verified by an expert reader. A deep learning model was trained using a double cross-validation scheme such that all data could be used as test data as well.

RESULTS

Area under the receiver-operating characteristic curve for the prediction of QCA, with > 50% narrowing of the artery, by deep learning for the external test cohort: per patient 85% [95% confidence interval (CI) 84%-87%] and per vessel; LAD 74% (CI 72%-76%), RCA 85% (CI 83%-86%), LCx 81% (CI 78%-84%), and average 80% (CI 77%-83%).

CONCLUSION

Deep learning can predict the presence of different QCA percentages of coronary artery stenosis from MPIs.

Visual patterns of breast attenuation artifacts in women and men with an upright and supine cadmiun-zinc-telluride camera

BACKGROUND

Breast attenuation artifacts occurring with upright cadmium-zinc-telluride (CZT) cardiac imaging systems have not been well characterized.

METHODS

216 consecutive patients with Single Photon Emission Computerized Tomography myocardial perfusion imaging and no angiographically significant obstructive coronary artery disease were identified. All upright and supine SPECT images as well as coronary angiograms were reviewed and analyzed in blinded fashion.

RESULTS

In women imaged upright, more visual false positive defects were noted in the inferior wall compared to the anterior wall (26 vs. 10 at rest, p = 0.006, and 33 vs. 13 at stress, p < 0.001). Visual inferior wall defects were more common in the upright than supine position at stress (33 vs. 23, p = 0.018) and rest (26 vs. 14, p = 0.011), and most apparent in non-obese women (13 vs. 8, at stress, p = 0.059 and 11 vs. 5, at rest, p = 0.014).

CONCLUSIONS

With upright CZT myocardial perfusion imaging, women often have visible inferior wall attenuation artifact defects, likely from pendant breast tissue. These inferior wall attenuation artifacts may be seen in non-obese female patients.

The effect of body mass index on high versus low administered activity protocol myocardial perfusion imaging scan time and effective dose using a cadmium zinc telluride camera in clinical practice

Cadmium Zinc Telluride (CZT) crystal-based myocardial perfusion imaging (MPI) cameras have increased count sensitivity compared to Anger cameras and can be used to lower either the injected activity or the image acquisition time. Institutions adopting CZT cameras need to decide whether to lower the injected activity or imaging time or attempt to lower both with a compromise. The aim of our study was to compare the scan time required to obtain similar count images using high activity protocol (HAP) versus low activity protocol (LAP) stratified by body mass index (BMI) and assess the impact on effective dose and our clinic workflow. Using a CZT camera, a cohort of 100 consecutive clinical patients imaged with LAP rest-stress MPI with approximately 185 MBq and 555 MBq activity was retrospectively compared to a similar cohort of 100 consecutive clinical patients imaged with HAP rest-stress MPI using approximately 370 MBq and 1110 MBq. Administered activity and BMI both had a statistically significant effect on scan time and radiation effective dose. LAP scans took an average of 9 min longer than HAP scans overall, P < 0.0001 and larger BMIs took longer than smaller BMIs, P < 0.0001. In addition, scan times were longer in men than women, P = 0.007. Effective dose was inversely proportional to BMI with an overall decrease of approximately 50% comparing LAP to HAP. For the same CZT camera, the LAP increased scan time while lowering the radiation effective dose when compared to HAP. The increase in scan time increased proportionally to BMI. The effective dose was inversely proportional to BMI. This increase in time did not have a significant impact on our local workflow, but its implications should be considered in the setting of LAP implementation, especially in obese or high patient volume practices.

Effects of gender and defect reversibility on detection of coronary disease with an upright and supine cadmium-zinc-telluride camera

BACKGROUND

Limited data address the roles of gender, perfusion defect reversibility, and imaging position in interpretation of images acquired on an upright/supine cadmium-zinc-telluride (CZT) cardiac imaging system.

METHODS AND RESULTS

From a consecutive cohort of patients imaged on an upright/supine CZT camera, 260 patients with coronary angiograms were studied. Multivariable models identified gender as a significant effect modifier for imaging variables of CAD. For males, a supine summed stress score (SSS) ≥ 3 provided high accuracy (sensitivity 70.7%, specificity 72.2%), and highest contribution to multivariable models. In females, supine SSS ≥ 2 provided the best cut-off for defect size and severity (sensitivity 90%, specificity 35.9%), but specificity was improved substantially to 53.3% with decrease in sensitivity to 80% by also requiring quantitative identification of perfusion defect reversibility in the supine position. Eight variables, accurate for predicting coronary disease, were more accurate with supine than upright imaging.

CONCLUSIONS

Perfusion defect reversibility improved specificity in female patients for detection of coronary disease compared to perfusion defect size and extent alone. Supine images provided superior accuracy for detection of coronary disease compared to upright images.

Machine learning predicts per-vessel early coronary revascularization after fast myocardial perfusion SPECT: results from multicentre REFINE SPECT registry

AIMS

To optimize per-vessel prediction of early coronary revascularization (ECR) within 90 days after fast single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) using machine learning (ML) and introduce a method for a patient-specific explanation of ML results in a clinical setting.

METHODS AND RESULTS

A total of 1980 patients with suspected coronary artery disease (CAD) underwent stress/rest 99mTc-sestamibi/tetrofosmin MPI with new-generation SPECT scanners were included. All patients had invasive coronary angiography within 6 months after SPECT MPI. ML utilized 18 clinical, 9 stress test, and 28 imaging variables to predict per-vessel and per-patient ECR with 10-fold cross-validation. Area under the receiver operator characteristics curve (AUC) of ML was compared with standard quantitative analysis [total perfusion deficit (TPD)] and expert interpretation. ECR was performed in 958 patients (48%). Per-vessel, the AUC of ECR prediction by ML (AUC 0.79, 95% confidence interval (CI) [0.77, 0.80]) was higher than by regional stress TPD (0.71, [0.70, 0.73]), combined-view stress TPD (AUC 0.71, 95% CI [0.69, 0.72]), or ischaemic TPD (AUC 0.72, 95% CI [0.71, 0.74]), all P < 0.001. Per-patient, the AUC of ECR prediction by ML (AUC 0.81, 95% CI [0.79, 0.83]) was higher than that of stress TPD, combined-view TPD, and ischaemic TPD, all P < 0.001. ML also outperformed nuclear cardiologists' expert interpretation of MPI for the prediction of early revascularization performance. A method to explain ML prediction for an individual patient was also developed.

CONCLUSION

In patients with suspected CAD, the prediction of ECR by ML outperformed automatic MPI quantitation by TPDs (per-vessel and per-patient) or nuclear cardiologists' expert interpretation (per-patient).

Added Value of CT Attenuation Correction and Prone Positioning in Improving Breast and Subdiaphragmatic Attenuation in Myocardial Perfusion Imaging

Soft-tissue attenuation of γ-photons is the most common source of artifacts and remains an intricate problem for myocardial perfusion imaging (MPI) by SPECT. Breast and subdiaphragmatic artifacts are the most frequent cause of false-positive findings in women. Many methods of overcoming attenuation artifacts have been introduced, including prone positioning to avoid breast attenuation or use of hybrid SPECT/CT systems. The purpose of this study was to evaluate the role of prone images in attenuation correction (AC) when CT AC is compared with MPI. Methods: Forty-four patients were initially included in the study. Statistical analysis was done for 30 patients with suspected or confirmed ischemic heart disease. All patients underwent ordinary supine stress/rest SPECT MPI followed by additional stress/rest prone SPECT and stress/rest SPECT/CT. Each study was interpreted separately, and their results were compared. Results: It was found that 58% (31/53) of the depicted defects were attributable to attenuation artifacts; the CT AC imaging technique was able to correct 52%, versus 49% for prone imaging. Sensitivity, specificity, and diagnostic accuracy were 100%, 90.3%, and 94%, respectively, for CT AC, versus 100%, 83.8%, and 91%, respectively, for prone imaging. Inferior wall defects were more common in men (95%), in whom CT AC performed better than prone imaging (i.e., 92.9% in CT AC vs. 90.9% in prone imaging). On the other hand, anterior wall defects were more common in women (83.3%), in whom prone imaging was better than CT AC. Conclusion: Both CT AC and prone imaging increased the specificity and diagnostic accuracy of MPI without affecting the sensitivity.

Introduction to the D-SPECT for Technologists: Workflow Using a Dedicated Digital Cardiac Camera

The D-SPECT is a dedicated cardiac camera that incorporates a solid-state semiconductor detector. This camera differs greatly from conventional SPECT/CT systems, resulting in significant differences in patient imaging. This continuing education article focuses on the specifications of both SPECT/CT and D-SPECT systems, radiopharmaceutical dosing requirements, imaging workflows, and some disadvantages of using each camera system. When used properly, the D-SPECT system can provide high-quality cardiac images with lower doses and faster exam times than conventional SPECT/CT systems.

Left ventricular mechanical dyssynchrony assessment in obese patients using the cadmium-zinc telluride SPECT camera

The use of phase analysis techniques to assess left ventricular mechanical dyssynchrony (LVMD) has been well documented. However, artifacts have reduced the accuracy of the assessment due to soft tissue attenuation, so little information is available about the effects of obesity on LVMD. The aim of this study was to evaluate LVMD in patients with simple obesity by SPECT with a new cadmium-zinc telluride (CZT) detector and to explore the effects of obesity on left ventricular wall motion. We retrospectively analyzed 95 patients with myocardial perfusion imaging (MPI) images without perfusion defects, of which 55 were diagnosed with simple obesity (BMI > 30), and 40 non-obese patients (BMI < 25) matched for age and sex were used as controls. The five-point method was used to analyze the MPI images of the two groups, and the complete cardiac function parameters including phase bandwidth (PBW) and phase standard deviation (PSD) were obtained. Although the PBW values of the two groups were within the normal range (cut-off value > 90°), the PBW (35.4 ± 28 vs 24.9 ± 7.5, P < .001; 36.6 ± 18.4 vs 28.7 ± 9.1, P = 0.01) and PSD (8.7 ± 7.6 vs 5.9 ± 2, P = 0.02; 9.2 ± 4.9 vs 7.1 ± 2.7, P = 0.01) of the obese group were larger than the control group under both stressing and resting, and the difference was statistically significant. CZT-SPECT can effectively assess LVMD in obese patients, and they are more likely to develop LVMD, which may be related to their left ventricular volume.

Current approach to the diagnosis of atherosclerotic coronary artery disease: more questions than answers

Despite its commonality in routine clinical practice, the approach to a diagnosis of atherosclerotic coronary artery disease remains complex and, in part, contentious. The traditional dogma linking ischaemia to hard clinical outcomes has been questioned and reframed over the years; rather than being a predictor of hard clinical outcomes, the degree of ischaemia may simply be a marker of atherosclerotic disease burden. A renewed interest in the imaging of plaque burden has spawned the contemporary role of CT imaging for not only diagnosis and prognosis, but also for dictating downstream management. As the technology develops and evidence expands, decisions on investigative modalities remain centred around patient factors, local availability, test performance and cost. This review summarizes the available methods for diagnosis in the symptomatic patient and provides an overview of the current evidence behind functional and anatomical approaches.

EANM procedural guidelines for myocardial perfusion scintigraphy using cardiac-centered gamma cameras

An increasing number of Nuclear Medicine sites in Europe are using cardiac-centered gamma cameras for myocardial perfusion scintigraphy (MPS). Three cardiac-centered gamma cameras are currently the most frequently used in Europe: the D-SPECT (Spectrum Dynamics), the Alcyone (Discovery NM 530c and Discovery NM/CT 570c; General Electric Medical Systems), and the IQ-SPECT (Siemens Healthcare). The increased myocardial count sensitivity of these three cardiac-centered systems has allowed for a decrease in the activities of radiopharmaceuticals injected to patients for myocardial perfusion imaging and, consequently, radiation exposure of patients. When setting up protocols for MPS, the overall objective should be to maintain high diagnostic accuracy of MPS, while injecting the lowest activities reasonably achievable to reduce the level of radiation exposure of patient and staff. These guidelines aim at providing recommendations for acquisition protocols and image interpretation using cardiac-centered cameras. As each imaging system has specific design and features for image acquisition and analysis, these guidelines have been separated into three sections for each gamma camera system. These recommendations have been written by the members of the Cardiovascular Committee of EANM and were based on their own experience with each of these systems and on the existing literature.

Recent advances in cardiac SPECT instrumentation and imaging methods

Cardiac SPECT continues to play a critical role in detecting and managing cardiovascular disease, in particularly coronary artery disease (CAD) (Jaarsma et al 2012 J. Am. Coll. Cardiol. 59 1719-28), (Agostini et al 2016 Eur. J. Nucl. Med. Mol. Imaging 43 2423-32). While conventional dual-head SPECT scanners using parallel-hole collimators and scintillation crystals with photomultiplier tubes are still the workhorse of cardiac SPECT, they have the limitations of low photon sensitivity (~130 count s^-1 MBq^-1), poor image resolution (~15 mm) (Imbert et al 2012 J. Nucl. Med. 53 1897-903), relatively long acquisition time, inefficient use of the detector, high radiation dose, etc. Recently our field observed an exciting growth of new developments of dedicated cardiac scanners and collimators, as well as novel imaging algorithms for quantitative cardiac SPECT. These developments have opened doors to new applications with potential clinical impact, including ultra-low-dose imaging, absolute quantification of myocardial blood flow (MBF) and coronary flow reserve (CFR), multi-radionuclide imaging, and improved image quality as a result of attenuation, scatter, motion, and partial volume corrections (PVCs). In this article, we review the recent advances in cardiac SPECT instrumentation and imaging methods. This review mainly focuses on the most recent developments published since 2012 and points to the future of cardiac SPECT from an imaging physics perspective.

Diagnostic value of cadmium-zinc-telluride myocardial perfusion imaging versus coronary angiography in coronary artery disease: A PRISMA-compliant meta-analysis

BACKGROUND

Rapid progress has been made in research of cadmium-zinc-telluride (CZT) technology in the last few years, which might serve as a new method to diagnose coronary artery disease. However, compared with coronary angiography, the diagnostic value of CZT is still controversial. We aimed to evaluate diagnosis value of coronary angiography versus CZT in coronary artery disease.

METHODS

We searched the database for eligible researches associated with CZT- myocardial perfusion imaging (MPI) and invasive coronary angiography, extracted the relevant data, and rigorously screened it according to the inclusion and exclusion criteria. The accuracy indicators included sensitivity, specificity, accuracy, positive and negative likelihood ratios.

RESULTS

According to the inclusion and exclusion criteria, we finally found 20 studies containing 2350 patients in this search. Pooled results showed that sensitivity of CZT-MPI was 0.84% and 95% confidence interval (95% CI): 0.78 to 0.89, specificity was 0.72, 95% CI (0.62-0.76), the specificity was lower apparently. The positive likelihood ratio was 3.0, 95% CI (2.4-3.8), the negative likelihood ratio was 0.22, 95% CI (0.16-0.31), diagnostic odds ratio was 14, 95% CI (7.84-17.42).

CONCLUSION

This meta-analysis showed that CZT-MPI had satisfactory sensitivity and specificity for diagnosing coronary artery disease. Larger studies are required for further evaluation.

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

This information statement from the American Society of Nuclear Cardiology highlights advances in cardiac SPECT imaging and supports the incorporation of new technology and techniques in laboratories performing nuclear cardiology procedures. The document focuses on the application of the latest imaging protocols and the utilization of newer hardware and software options to perform high quality, state-of-the-art SPECT nuclear cardiology procedures. Recommendations for best practices of cardiac SPECT imaging are discussed, highlighting what imaging laboratories should be doing as the standard of care in 2018 to achieve optimal results (based on the ASNC 2018 SPECT guideline [Dorbala et al., J Nucl Cardiol. 2018. https://doi.org/10.1007/s12350-018-1283-y ]).

Effect of patient positioning on the evaluation of myocardial perfusion SPECT

BACKGROUND

ECG-gated SPECT myocardial perfusion imaging is usually acquired in supine position. However, some patients are not comfortable in this position for a variety of personal or medical reasons. Our aim was to investigate the effect of patient positioning on quantitative SPECT imaging results using normal supine database.

METHODS

55 patients (mean age 58.5 ± 8.3 years) were enrolled in this prospective study. Each patient had a pair of ECG-gated stress SPECT myocardial perfusion images acquired on two gamma cameras: one in supine position and the other in upright sitting position. Left ventricular (LV) ejection fraction (EF), end-diastolic (ED), and end-systolic (ES) left ventricular volumes (V), LV mass, summed stress perfusion defect score (SSS), and total severity score (TSS) were calculated automatically relative to a supine normal reference database.

RESULTS

There were no significant differences in LVEF using the two cameras (0.65 ± 0.08 vs. 0.66 ± 0.10; P > 0.1). However, EDV, ESV, and LV mass were significantly smaller in sitting position than in supine position (89 vs. 80 ml; 33 vs. 29 ml and 115 vs. 109 ml, respectively, all P < 0.0001). On the other hand, SSS and TSS were significantly higher in sitting position than in supine position (5.16 vs. 8.73 and 166.82 vs. 288.27, both P < 0.0001). Overall, more studies in sitting position were interpreted as abnormal than in supine position (P < 0.05).

CONCLUSION

Patient positioning has a significant impact on quantitative gated SPECT imaging results. Using a supine normal reference database, SSS and TSS were larger in sitting position than in supine position. Thus, for imaging in sitting position, separate normal limits are required.

Criteria for the addition of prone imaging to myocardial perfusion single-photon emission computed tomography for inferior wall

OBJECTIVE

Myocardial perfusion single-photon emission computed tomography (SPECT) is occasionally suspected to generate images that represent either ischemia or infarction for the inferior wall [right coronary artery (RCA) disease] or attenuation artifacts because of the diaphragm. We often encounter this. The application of prone imaging is advantageous in the differentiation of RCA disease because of attenuation artifacts. If decreased accumulation of radioisotopes is observed at the site with either RCA disease or attenuation artifacts, then a criterion that enables the addition of prone imaging should be implemented. Then, we evaluated sites where RCA disease and attenuation artifacts would likely appear and investigated the threshold of decreased accumulation that enables utilization of prone imaging.

PATIENTS AND METHODS

The patients in this study were divided into two groups: group A (20 patients) suspected to have attenuation artifacts because of the diaphragm and group B (14 patients) with RCA disease. Additional evaluation by prone imaging was performed in all patients. We utilized a 20-segment quantitative perfusion SPECT polar map in the supine and prone positions to compare the percentage increase in Thallium chloride (Tl) in both groups. We then investigated the percent uptake (%uptake) value of decreased accumulation in the inferior wall for the addition of prone imaging.

RESULTS

The highest %uptake was present in segments 3, 4, 5, and 10 in group A after the prone imaging. Detection of attenuation artifacts from the diaphragm was easy in segments 3, 4, 5, and 10, and we set the %uptake threshold at 62, 61, 71, and 76%, respectively, in the supine position for the addition of prone imaging.

CONCLUSION

A decrease of the %uptake in segments 3, 4, 5, and 10 after supine imaging is presumed to result from attenuation artifact or RCA disease. We established evaluation criteria for the addition of prone imaging in patients with decreased accumulation in the inferior wall during supine imaging.

Myocardial perfusion imaging in women for the evaluation of stable ischemic heart disease-state-of-the-evidence and clinical recommendations

This document from the American Society of Nuclear Cardiology represents an updated consensus statement on the evidence base of stress myocardial perfusion imaging (MPI), emphasizing new developments in single-photon emission tomography (SPECT) and positron emission tomography (PET) in the clinical evaluation of women presenting with symptoms of stable ischemic heart disease (SIHD). The clinical evaluation of symptomatic women is challenging due to their varying clinical presentation, clinical risk factor burden, high degree of comorbidity, and increased risk of major ischemic heart disease events. Evidence is substantial that both SPECT and PET MPI effectively risk stratify women with SIHD. The addition of coronary flow reserve (CFR) with PET improves risk detection, including for women with nonobstructive coronary artery disease and coronary microvascular dysfunction. With the advent of PET with computed tomography (CT), multiparametric imaging approaches may enable integration of MPI and CFR with CT visualization of anatomical atherosclerotic plaque to uniquely identify at-risk women. Radiation dose-reduction strategies, including the use of ultra-low-dose protocols involving stress-only imaging, solid-state detector SPECT, and PET, should be uniformly applied whenever possible to all women undergoing MPI. Appropriate candidate selection for stress MPI and for post-MPI indications for guideline-directed medical therapy and/or invasive coronary angiography are discussed in this statement. The critical need for randomized and comparative trial data in female patients is also emphasized.

Diagnostic Accuracy of Myocardial Perfusion Imaging With CZT Technology: Systemic Review and Meta-Analysis of Comparison With Invasive Coronary Angiography

OBJECTIVES

This study sought to summarize the evidence on stress myocardial perfusion imaging (MPI) using cadmium-zinc-telluride (CZT) technology for the diagnosis of obstructive coronary artery disease (CAD). The CZT cameras are newly introduced, and comparative data with the conventional Anger technology (Anger-MPI) are lacking.

BACKGROUND

The diagnostic accuracy of Anger-MPI for detection of angiographically significant CAD is well established; however, less evidence is available on the diagnostic accuracy of CZT-MPI.

METHODS

Clinical studies comparing CZT-MPI and invasive coronary angiography were systematically searched and abstracted. Calculations of diagnostic accuracy, including sensitivity, specificity, likelihood ratios, and diagnostic odds ratio, were obtained with fixed and random effects, reporting point estimates and 95% confidence intervals.

RESULTS

Based on our search, a total of 16 studies (N = 2,092) were included. The sensitivity of CZT-MPI was 0.84 (95% confidence interval [CI]: 0.78 to 0.89), whereas the specificity of 0.69 (95% CI: 0.62 to 0.76) was significantly reduced. The positive likelihood ratio was 2.73 (95% CI: 2.21 to 3.39), the negative likelihood ratio was 0.24 (95% CI: 0.17 to 0.31), and the diagnostic odds ratio was 11.93 (95% CI: 7.84 to 17.42). At subgroup and meta-regression analyses, the diagnostic accuracy between D-SPECT and Discovery cameras was similar (p = 0.711) and not impacted upon by smaller sample size studies (p = 0.573).

CONCLUSIONS

CZT-MPI has satisfactory sensitivity for angiographically significant CAD, but its suboptimal specificity warrants further development and research.

Evaluation of Cadmium-Zinc-Telluride Detector-based Single-Photon Emission Computed Tomography for Nuclear Cardiology: a Comparison with Conventional Anger Single-Photon Emission Computed Tomography

Purpose

The differences in performance between the cadmium-zinc-telluride (CZT) camera or collimation systems and conventional Anger single-photon emission computed tomography (A-SPECT) remain insufficient from the viewpoint of the user. We evaluated the performance of the D-SPECT (Spectrum Dynamics, Israel) system to provide more information to the cardiologist or radiological technologist about its use in the clinical field.

Materials and Methods

This study evaluated the performance of the D-SPECT system in terms of energy resolution, detector sensitivity, spatial resolution, modulation transfer function (MTF), and collimator resolution in comparison with that of A-SPECT (Bright-View, Philips, Japan). Energy resolution and detector sensitivity were measured for Tc-99m, I-123, and Tl-201. The SPECT images produced by both systems were evaluated visually using the anthropomorphic torso phantom.

Results

The energy resolution of D-SPECT with Tc-99m and I-123 was approximately two times higher than that of A-SPECT. The detector sensitivity of D-SPECT was higher than that of A-SPECT (Tc-99m: 4.2 times, I-123: 2.2 times, and Tl-201: 5.9 times). The mean spatial resolution of D-SPECT was two times higher than that of A-SPECT. The MTF of D-SPECT was superior to that of the A-SPECT system for all frequencies. The collimator resolution of D-SPECT was lower than that of A-SPECT; however, the D-SPECT images clearly indicated better spatial resolution than the A-SPECT images.

Conclusion

The energy resolution, detector sensitivity, spatial resolution, and MTF of D-SPECT were superior to those of A-SPECT. Although the collimator resolution was lower than that of A-SPECT, the D-SPECT images were clearly of better quality.

Performance of cardiac cadmium-zinc-telluride gamma camera imaging in coronary artery disease: a review from the cardiovascular committee of the European Association of Nuclear Medicine (EANM)

The trade-off between resolution and count sensitivity dominates the performance of standard gamma cameras and dictates the need for relatively high doses of radioactivity of the used radiopharmaceuticals in order to limit image acquisition duration. The introduction of cadmium-zinc-telluride (CZT)-based cameras may overcome some of the limitations against conventional gamma cameras. CZT cameras used for the evaluation of myocardial perfusion have been shown to have a higher count sensitivity compared to conventional single photon emission computed tomography (SPECT) techniques. CZT image quality is further improved by the development of a dedicated three-dimensional iterative reconstruction algorithm, based on maximum likelihood expectation maximization (MLEM), which corrects for the loss in spatial resolution due to line response function of the collimator. All these innovations significantly reduce imaging time and result in a lower patient's radiation exposure compared with standard SPECT. To guide current and possible future users of the CZT technique for myocardial perfusion imaging, the Cardiovascular Committee of the European Association of Nuclear Medicine, starting from the experience of its members, has decided to examine the current literature regarding procedures and clinical data on CZT cameras. The committee hereby aims 1) to identify the main acquisitions protocols; 2) to evaluate the diagnostic and prognostic value of CZT derived myocardial perfusion, and finally 3) to determine the impact of CZT on radiation exposure.

Pitfalls and artifacts using the D-SPECT dedicated cardiac camera

Myocardial perfusion imaging is a well-established and widely used imaging technique for the assessment of patients with known or suspected coronary artery disease. Pitfalls and artifacts associated with conventional gamma cameras are well known, and the ways to avoid and correct them have been described. In recent years solid-state detector dedicated cardiac cameras were introduced and have been shown to offer improved accuracy in addition to new imaging protocols and novel applications. The purpose of this manuscript is to familiarize the readers with the causes and effects of technical, patient-related, and operator-related pitfalls and artifacts associated with the D-SPECT dedicated cardiac camera with solid-state detectors. The manuscript offers guidance on how to avoid these factors, how to detect them, and how to correct better for them, providing high-quality diagnostic images.

EANM procedural guidelines for radionuclide myocardial perfusion imaging with SPECT and SPECT/CT: 2015 revision

Since the publication of the European Association of Nuclear Medicine (EANM) procedural guidelines for radionuclide myocardial perfusion imaging (MPI) in 2005, many small and some larger steps of progress have been made, improving MPI procedures. In this paper, the major changes from the updated 2015 procedural guidelines are highlighted, focusing on the important changes related to new instrumentation with improved image information and the possibility to reduce radiation exposure, which is further discussed in relation to the recent developments of new International Commission on Radiological Protection (ICRP) models. Introduction of the selective coronary vasodilator regadenoson and the use of coronary CT-contrast agents for hybrid imaging with SPECT/CT angiography are other important areas for nuclear cardiology that were not included in the previous guidelines. A large number of minor changes have been described in more detail in the fully revised version available at the EANM home page: http://eanm.org/publications/guidelines/2015_07_EANM_FINAL_myocardial_perfusion_guideline.pdf.

Feasibility of SPECT myocardial perfusion imaging in the super-obese using a multi-head semiconductor camera with attenuation correction

BACKGROUND

Obesity is not only associated with an increased risk of coronary artery disease, but also decreases the accuracy of many diagnostic modalities pertinent to this disease. Advances in myocardial perfusion imaging (MPI) have mitigated somewhat the effects of obesity, although the feasibility of MPI in the super-obese (defined as a BMI > 50) is currently untested. We undertook this study to assess the practicality of MPI in the super-obese using a multi-headed solid-state gamma camera with attenuation correction.

METHODS

We retrospectively identified consecutive super-obese patients referred for MPI at our institution. The images were interpreted by 3 blinded, experienced readers and graded for quality and diagnosis, and subjectively evaluated the contribution of attenuation correction. Clinical follow-up was obtained from review of medical records.

RESULTS

72 consecutive super-obese patients were included. Their BMI ranged from 50 to 67 (55.7 ± 5.1). Stress image quality was considered good or excellent in 45 (63%), satisfactory in 24 (33%), poor in 3 (4%), and uninterpretable in 0 patients. Rest images were considered good or excellent in 34 (49%), satisfactory in 23 (33%), poor in 13 (19%), and uninterpretable in 0 patients. Attenuation correction changed the interpretation in 34 (47%) of studies.

CONCLUSIONS

MPI is feasible and provides acceptable image quality for super-obese patients, although it may be camera and protocol dependent.