Development of an MR-compatible SPECT system (MRSPECT) for simultaneous data acquisition

Abstract

In medical imaging, single-photon emission computed tomography (SPECT) can provide specific functional information while magnetic resonance imaging (MRI) can provide high spatial resolution anatomical information as well as complementary functional information. In this study, we developed a miniaturized dual-modality SPECT/MRI (MRSPECT) system and demonstrated the feasibility of simultaneous SPECT and MRI data acquisition, with the possibility of whole-body MRSPECT systems through suitable scaling of components. For our MRSPECT system, a cadmium-zinc-telluride (CZT) nuclear radiation detector was interfaced with a specialized radiofrequency (RF) coil and placed within a whole-body 4 T MRI system. Various phantom experiments characterized the interaction between the SPECT and MRI hardware components. The metallic components of the SPECT hardware altered the B(0) field and generated a non-uniform reduction in the signal-to-noise ratio (SNR) of the MR images. The presence of a magnetic field generated a position shift and resolution loss in the nuclear projection data. Various techniques were proposed to compensate for these adverse effects. Overall, our results demonstrate that accurate, simultaneous SPECT and MRI data acquisition is feasible, justifying the further development of MRSPECT for either small-animal imaging or whole-body human systems by using appropriate components.

Development and evaluation of a dual-modality (MRI/SPECT) molecular imaging bioprobe

“…Dual-modality imaging with SPECT and MRI thus provides anatomical references in an image while synergistically combining the high spatial resolution associated with MR with the high sensitivity of SPECT. 3 Dual-modality SPECT/MR imaging bioprobes would allow for simultaneous dynamic imaging of structure and function, facilitate noninvasive monitoring of treatment, and directly provide information on pharmacokinetics and metabolism of drugs. Additionally, simultaneous dualmodality imaging can reduce the overall scan time, avoids multiple anesthesia sessions, and prevents errors associated with coregistration.…”

“…5,6 Similar design principles apply to the development of SPECT/MRI scanners, where semiconductor detectors (cadmium-zinc-telluride [CZT]) used in small-animal SPECT were shown to be insensitive to magnetic fields up to 7 T, leading to the development of a prototype for simultaneous SPECT/MRI systems. 2 The feasibility of simultaneous SPECT and MRI data acquisition was demonstrated recently, 3 justifying the further development of SPECT/MRI for small-animal and whole-body human imaging. We report on the development of a dual-modality SPECT/MR imaging agent for use with such dual-modality scanners.…”

Tomographic bioluminescence imaging reconstruction via a dynamically sparse regularized global method in mouse models

“…Generally, data fusion from different modalities plays an indispensable role for high imaging fidelity, [53][54][55] as specially in tomographic bioluminescence imaging, and it is also necessary to combine the information from optical and micro-CT modalities. The data fusion between bioluminescence imaging and micro-CT is helpful to alleviate the ill-posedness and improve imaging quality.…”

An outlook on future design of hybrid PET/MRI systems

“…The first prototypes for small-animal imaging are now available. [203][204][205] SPECT/MR will provide an additional and improved multimodality information to the hybrid imaging field in the near future.…”