Major Achievements in Nuclear Cardiology
Advances in technical aspects of myocardial perfusion SPECT imaging

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New Hardware for Optimized MPS Imaging

Several new dedicated hardware camera systems with optimized acquisition geometry, collimator design, and associated reconstruction software have been recently introduced by various vendors. Innovative designs of the gantry and detectors have been proposed which allow increased sampling of the myocardial region, and thus allow better local sensitivity. These systems combine an improvement in spatial resolution and sensitivity. By faster imaging times due to increased sensitivity and by

Digirad Cardius 3 XPO

Digirad, Inc. (Poway, CA) has developed a Cardius XPO camera dedicated to fast cardiac imaging. This system can be configured in 2- or 3-detector configurations.3 The Cardius 3 camera and its geometry (triple-head configuration) is shown in Figure 1. These models use indirect, solid-state detectors consisting of pixilated CsI(Tl) and photodiodes to configure detector heads that are more compact than conventional cameras, equipped with photomultipliers. Each detector head is 21.2 × 15.8 cm and

CardiArc

CardiArc (Canton, MI) has developed a dedicated nuclear cardiology SPECT camera in which the detector and collimation are redesigned and optimized specifically for cardiac imaging.7 This device has no visibly moving parts and has a single internally moving part which is hidden from the patient.8 Therefore from the outside the detector appears motionless, and for comfort the patient is positioned upright. Scan times reported by the company are as short as 2 minutes.7 The camera system and a

Spectrum Dynamics

Spectrum Dynamics, Haifa, Israel, has manufactured a system called D-SPECT. The design and the principle of its operation are shown in Figure 6. The patient is imaged in a semi-upright position with the left arm placed on top of the camera (Figure 6A) or in the supine position. Acquisition time as short as 2 minutes has been reported.11 This system uses pixilated CZT detector arrays (Figure 6B) mounted in 9 vertical columns and placed in a 90° gantry geometry (Figure 6C). While CZT detectors

Multi-Pinhole Collimation Approach

Some vendors have explored image collimation using multi-pinhole design. Multi-pinhole collimation provides an alternative approach to parallel-hole rotational tomography. Previously, useful results have been demonstrated in small animal imaging with multi-pinhole SPECT providing improved spatial resolution and detection efficiency in comparison to parallel-hole collimation.18, 19, 20 The multi-pinhole approach allows many views to be acquired simultaneously throughout the entire image

Eagle Heart Imaging

Existing SPECT systems with one or more large-area detectors are potentially adaptable to the stationary multi-pinhole SPECT approach. Eagle Heart Imaging (Westminster, Colorado) has integrated multi-pinhole methodology with the Emory Reconstruction Toolbox (Syntermed, Atlanta, GA) to provide a commercial multi-pinhole upgrade product called MP-SPECT™ for existing dual-head SPECT gamma cameras.

Figure 10 illustrates an approach for upgrading a standard dual-detector SPECT camera for imaging the

GE Healthcare Ultra Fast Cardiac (UFC) Camera

General Electric Healthcare recently (SNM 2008) introduced the UFC camera based on the multi-pinhole design and an array of cadmium zinc telluride (CZT) pixilated detectors. The camera has received 510(k) clearance from the U.S. Food and Drug Administration (FDA) and is manufactured by GE Healthcare. The use of CZT improves the energy and spatial resolution while the use of simultaneously acquired views improves the overall sensitivity and gives complete and consistent angular data needed for

Siemens IQ•SPECT

Siemens introduced recently (SNM 2008) IQ•SPECT, which consists of three components: an astigmatic collimator, an optimized organ-of-interest centered acquisition, and iterative reconstruction. The collimator is based on a previously developed astigmatic (cardiofocal) collimator concept.28 The collimator is designed so that the center of the field-of-view magnifies the heart both in axial as well as in trans-axial direction, while the edges sample the entire body to avoid truncation artifacts

Reconstruction Algorithms for Fast Imaging with Standard MPS Systems

Faster MPS imaging can be also accomplished by advanced image reconstruction techniques, which improve image contrast and reduce noise levels inherent in images with low counts reconstructed with filtered back-projection (FBP). These developments have centered on the development of new proprietary algorithms based on maximum likelihood expectation-maximization (MLEM)32,33 and accelerated method of ordered subsets expectation maximization (OSEM).34

FBP reconstruction assumes that the object is

Philips Astonish

Philips (San Jose, CA) has developed a fast SPECT reconstruction algorithm (Astonish) that includes corrections for the major factors degrading SPECT image quality. It is based on the OSEM reconstruction method with built-in noise reduction methods during the iterative process, and incorporating corrections for photon scatter, photon attenuation, and variations in spatial resolution. Correction for Compton scattering in the patient improves lesion contrast and is required for accurate

General Electric Healthcare—Evolution Software

General Electric Healthcare, Waukesha, WI, has developed a modification of the OSEM algorithm which incorporates resolution recovery or OSEM-RR (Evolution for Cardiac). Their approach includes modeling of the integrated collimator and detector response function (CDR) in an iterative reconstruction algorithm and performs image resolution recovery43 based on these parameters. This technique has been described in detail by DePuey et al.44 The OSEM-RR modeling includes basic collimator geometric

Siemens Flash 3D

Siemens has developed software (Flash3D) incorporating iterative fast OSEM reconstruction with 3D resolution recovery, 3D Collimator and Detector Response Correction, and attenuation and scatter compensation.50 SPECT cardiac acquisition protocols (CardioFlash) have been developed utilizing Flash3D, where the acquisition time can be reduced to between 33% and 50%, as compared to the standard acquisition protocols with FBP reconstruction. An example of the image quality obtained with CardioFlash

UltraSPECT Wide Beam Reconstruction

UltraSpect, Inc. (Haifa, Israel) has developed a standalone workstation (Xpress.cardiac) which utilizes the patented wide beam reconstruction (WBR™) algorithm.53 The WBR reconstruction technique, phantom validation, and its clinical application have been recently described by Borges-Neto et al.54 This system is available as an additional workstation and can reconstruct data from most existing gamma cameras with standard collimators. WBR models the physics and geometry of the emission and

Motion-Frozen Reconstruction

A related technical development resulting in improved MPS image quality is the “motion-frozen” processing of gated cardiac images, which eliminates blurring of perfusion images due to cardiac motion.56 This technique applies a non-linear, thin-plate-spline warping algorithm and shifts counts from the whole cardiac cycle into the end diastolic position. The “motion-frozen” images have the appearance of ED frames but are significantly less noisy since the counts from the entire cardiac cycle are

Conclusions

Nuclear cardiology imaging techniques are undergoing revolutionary changes in the last few years. Novel iterative reconstruction methods, which include modeling of physical phenomena and acquisition geometry, can facilitate the acceleration of image acquisition on standard gamma cameras approximately by a factor of at least 2 or more with equivalent image quality. Novel dedicated detectors and collimators optimized specifically for MPS combined with these new reconstruction approaches achieve

Acknowledgments

Daniel Berman has equity position in Spectrum Dynamics, Inc. We would like to acknowledge help of the following individuals who have sent material, data, and images relating to specific technologies: Gordon DePuey, Columbia University, NYC; Gary Heller University of Connecticut School of Medicine CT; Ernest V. Garcia, Emory University, Atlanta, GA; Hans Vija, Siemens Medical Solutions, Hoffman Estates, IL; Horace Hines and Angela Da Silva Philips, Malpitas, CA; Dennis Kirch, Nuclear Research,

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References (57)

  • EinsteinAJ et al.

    Estimating risk of cancer associated with radiation exposure from 64-slice computed tomography coronary angiography

    JAMA

    (2007)
  • Babla H, Bai C, Conwell R. A triple-head solid state camera for cardiac single photon emission tomography (SPECT). In:...
  • LewinHC et al.

    A clinical comparison of an upright triple-head digital detector system to a standard supine dual-head gamma camera (abstract)

    J Nucl Cardiol

    (2005)
  • Bai C, Conwell R, Babla H, et al. Improving image quality and imaging efficiency using nSPEED....
  • MaddahiJ et al.

    Prospective multi-center evaluation of rapid gated SPECT myocardial perfusion upright imaging (abstract)

    J Nucl Med

    (2008)
  • http//www.CardiArc.com. Accessed 30 May...
  • MadsenMT

    Recent advances in SPECT imaging

    J Nucl Med

    (2007)
  • O'ConnorM

    Evaluation of the CardiArc dedicated cardiac system (unpublished independent evaluation)

    Rochester, MN: Mayo Clinic

    (2005)
  • Rousso B, Nagler M. Spectrum Dynamics LLC, assignee. Multidimensional image reconstruction. US patent 7176466. 13 Feb...
  • HinesH et al.

    Recommendations for implementing SPECT instrumentation quality control

    Eur J Nucl Med Mol Imaging

    (1999)
  • PattonJ et al.

    D-SPECT: A new solid state camera for high speed molecular imaging

    Soc Nuclear Med

    (2006)
  • BermanD et al.

    Stress thallium-201/rest Tc-99m sequential dual isotope high-speed myocardial perfusion imaging

    Circulation

    (2008)
  • JaszczakRJ et al.

    Pinhole collimation for ultra-high-resolution, small-field-of-view SPECT

    Phys Med Biol

    (1994)
  • SchrammNU et al.

    High-resolution SPECT using multipinhole collimation

    IEEE Trans Nucl Sci

    (2003)
  • BeekmanFJ et al.

    Design and simulation of a high-resolution stationary SPECT system for small animals

    Phys Med Biol

    (2004)
  • FunkT et al.

    A novel approach to multipinhole SPECT for myocardial perfusion imaging

    J Nucl Med

    (2006)
  • MetzlerSD et al.

    Analytic determination of pinhole collimator sensitivity with penetration

    IEEE Trans Med Imaging

    (2001)
  • FunkT et al.

    A multipinhole small animal SPECT system with submillimeter spatial resolution

    Med Phys

    (2006)
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