scholarly journals Reconstruction for Limited-Projection Fluorescence Molecular Tomography Based on a Double-Mesh Strategy

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Huangjian Yi ◽  
Xu Zhang ◽  
Jinye Peng ◽  
Fengjun Zhao ◽  
Xiaodong Wang ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Small Animal ◽  
Initial Result ◽  
Acquisition Time ◽  
Feasible Region ◽  
Fluorescence Molecular Tomography ◽  
Fluorescence Measurements ◽  
Region Extraction ◽  
Data Acquisition Time

Limited-projection fluorescence molecular tomography (FMT) has short data acquisition time that allows fast resolving of the three-dimensional visualization of fluorophore within small animal in vivo. However, limited-projection FMT reconstruction suffers from severe ill-posedness because only limited projections are used for reconstruction. To alleviate the ill-posedness, a feasible region extraction strategy based on a double mesh is presented for limited-projection FMT. First, an initial result is rapidly recovered using a coarse discretization mesh. Then, the reconstructed fluorophore area in the initial result is selected as a feasible region to guide the reconstruction using a fine discretization mesh. Simulation experiments on a digital mouse and small animal experiment in vivo are performed to validate the proposed strategy. It demonstrates that the presented strategy provides a good distribution of fluorophore with limited projections of fluorescence measurements. Hence, it is suitable for reconstruction of limited-projection FMT.

INFLUENCE OF LIMITED-PROJECTION ON FLUORESCENCE MOLECULAR TOMOGRAPHY

2012 ◽  
Vol 05 (03) ◽  
pp. 1250020 ◽  
Author(s):  
YUN HE ◽  
XU CAO ◽  
FEI LIU ◽  
JIANWEN LUO ◽  
JING BAI
Keyword(s):  
Data Acquisition ◽  
Systematic Investigation ◽  
Acquisition Time ◽  
Projection Data ◽  
Fluorescence Molecular Tomography ◽  
Time Data ◽  
Phantom Experiment ◽  
Reconstruction Quality ◽  
Data Acquisition Time

Challenges remain in imaging fast biological processes in vivo with fluorescence molecular tomography (FMT) due to the long data acquisition time. Data acquisition with limited projections can greatly reduce the time consumption, but the influence of limited-projection on reconstruction quality is currently unclear. Both numerical simulations and a phantom experiment are conducted to analyze this problem. Through a systematic investigation of all the results reconstructed from different numbers of projections, we evaluate the influence of limited-projection data on FMT. A mouse experiment is also performed to validate our work. A general relationship between the number of projections and reconstruction quality is obtained which indicates that the projection number of three is preferred for fast FMT experiment.

scholarly journals Capabilities of multi-pinhole SPECT with two stationary detectors for in vivo rat imaging

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Jan P. Janssen ◽  
Jan V. Hoffmann ◽  
Takayuki Kanno ◽  
Naoko Nose ◽  
Jan-Peter Grunz ◽  
...  
Keyword(s):  
Image Quality ◽  
Point Source ◽  
Single Photon ◽  
Photon Emission ◽  
Small Animal ◽  
Acquisition Time ◽  
Emission Computed Tomography ◽  
Scan Time ◽  
Spect System

Abstract We aimed to investigate the image quality of the U-SPECT5/CT E-Class a micro single-photon emission computed tomography (SPECT) system with two large stationary detectors for visualization of rat hearts and bones using clinically available 99mTc-labelled tracers. Sensitivity, spatial resolution, uniformity and contrast-to-noise ratio (CNR) of the small-animal SPECT scanner were investigated in phantom studies using an ultra-high-resolution rat and mouse multi-pinhole collimator (UHR-RM). Point source, hot-rod, and uniform phantoms with 99mTc-solution were scanned for high-count performance assessment and count levels equal to animal scans, respectively. Reconstruction was performed using the similarity-regulated ordered-subsets expectation maximization (SROSEM) algorithm with Gaussian smoothing. Rats were injected with ~ 100 MBq [99mTc]Tc-MIBI or ~ 150 MBq [99mTc]Tc-HMDP and received multi-frame micro-SPECT imaging after tracer distribution. Animal scans were reconstructed for three different acquisition times and post-processed with different sized Gaussian filters. Following reconstruction, CNR was calculated and image quality evaluated by three independent readers on a five-point scale from 1 = “very poor” to 5 = “very good”. Point source sensitivity was 567 cps/MBq and radioactive rods as small as 1.2 mm were resolved with the UHR-RM collimator. Collimator-dependent uniformity was 55.5%. Phantom CNR improved with increasing rod size, filter size and activity concentration. Left ventricle and bone structures were successfully visualized in rat experiments. Image quality was strongly affected by the extent of post-filtering, whereas scan time did not have substantial influence on visual assessment. Good image quality was achieved for resolution range greater than 1.8 mm in bone and 2.8 mm in heart. The recently introduced small animal SPECT system with two stationary detectors and UHR-RM collimator is capable to provide excellent image quality in heart and bone scans in a rat using standardized reconstruction parameters and appropriate post-filtering. However, there are still challenges in achieving maximum system resolution in the sub-millimeter range with in vivo settings under limited injection dose and acquisition time.

Strain Mapping From Four-Dimensional Ultrasound Reveals Complex Remodeling in Dissecting Murine Abdominal Aortic Aneurysms

2019 ◽  
Vol 141 (6) ◽  
Author(s):  
Hannah L. Cebull ◽  
Arvin H. Soepriatna ◽  
John J. Boyle ◽  
Sean M. Rothenberger ◽  
Craig J. Goergen
Keyword(s):  
Three Dimensional ◽  
Small Animal ◽  
Aortic Aneurysms ◽  
Maximum Diameter ◽  
High Frequency Ultrasound ◽  
4D Ultrasound ◽  
Abdominal Aortic ◽  
Lagrange Strain ◽  
Aortic Strain

Current in vivo abdominal aortic aneurysm (AAA) imaging approaches tend to focus on maximum diameter but do not measure three-dimensional (3D) vascular deformation or strain. Complex vessel geometries, heterogeneous wall compositions, and surrounding structures can all influence aortic strain. Improved understanding of complex aortic kinematics has the potential to increase our ability to predict aneurysm expansion and eventual rupture. Here, we describe a method that combines four-dimensional (4D) ultrasound and direct deformation estimation to compute in vivo 3D Green-Lagrange strain in murine angiotensin II-induced suprarenal dissecting aortic aneurysms, a commonly used small animal model. We compared heterogeneous patterns of the maximum, first-component 3D Green-Lagrange strain with vessel composition from mice with varying AAA morphologies. Intramural thrombus and focal breakage in the medial elastin significantly reduced aortic strain. Interestingly, a dissection that was not detected with high-frequency ultrasound also experienced reduced strain, suggesting medial elastin breakage that was later confirmed via histology. These results suggest that in vivo measurements of 3D strain can provide improved insight into aneurysm disease progression. While further work is needed with both preclinical animal models and human imaging studies, this initial murine study indicates that vessel strain should be considered when developing an improved metric for predicting aneurysm growth and rupture.

Diffusion Tensor Imaging and 3D Tractography of the Cervical Spinal Cord Using the ECG-Gated Line-Scan Technique

2007 ◽  
Vol 20 (5) ◽  
pp. 574-579 ◽  
Author(s):  
M. Hori ◽  
K. Ishigame ◽  
S. Aoki ◽  
H. Kumagai ◽  
T. Araki
Keyword(s):  
Spinal Cord ◽  
Clinical Symptoms ◽  
Diffusion Tensor ◽  
Cervical Spinal Cord ◽  
Three Dimensional ◽  
Acquisition Time ◽  
Clinical Use ◽  
Ecg Gating ◽  
Line Scan

Diffusion tensor (DT) magnetic resonance (MR) imaging in addition to conventional MR images provide valuable information on the brain. This study compared line scan DT imaging with and without the ECG-gating technique to estimate clinical usefulness of the line scan diffusion tensor image (LSDTI) with ECG-gating in evaluating spinal cord diseases in vivo. First, five healthy volunteers participated in the comparison study. LSDWI was performed in three to five sagittal sections with a pulsed-field-gradient diffusion preparation pulse employing two different b-values (0 and 700 s/mm2) along six directions. Apparent diffusion coefficient (ADC) maps and fractional anisotropy (FA) were calculated and three-dimensional tract reconstruction and color schemes of the spinal cord were obtained. Image quality and the acquisition time of each LSDTI were compared. Second, LSDTI with ECG-gating was performed in eighteen patients with cervical spinal cord disorders and evaluated by two neuroradiologists. Images with the ECG-gated technique were all superior to those without ECG—gating. Mean extended time for LSDTI with ECG-gating was approximately two minutes. In clinical use, the ADC and FA of spinal cord in patients with cervical spondylotic myelopathy statically changed. Moreover, demonstration of fibers was correlated with clinical symptoms. ECG-gating technique is preferable to LSDTI. The ADC and FA measurements and 3D fiber tracking of LSDTI with ECG-gating are promising methods to estimate cervical spinal cord pathology in clinical use.

scholarly journals Three-Dimensional in Vivo Imaging of Green Fluorescent Protein-Expressing T Cells in Mice with Noncontact Fluorescence Molecular Tomography

2007 ◽  
Vol 6 (2) ◽  
pp. 7290.2007.00007 ◽  
Author(s):  
Anikitos Garofalakis ◽  
Giannis Zacharakis ◽  
Heiko Meyer ◽  
Eleftherios N. Economou ◽  
Clio Mamalaki ◽  
...  
Keyword(s):  
T Cells ◽  
Green Fluorescent Protein ◽  
In Vivo Imaging ◽  
Fluorescent Protein ◽  
Three Dimensional ◽  
Fluorescence Molecular Tomography ◽  
Green Fluorescent

scholarly journals Normalized Born Approximation-Based Two-Stage Reconstruction Algorithm for Quantitative Fluorescence Molecular Tomography

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Huangjian Yi ◽  
Duofang Chen ◽  
Wei Li ◽  
Shuang Zhou ◽  
Miao Ning ◽  
...  
Keyword(s):  
Born Approximation ◽  
Small Animal Imaging ◽  
Small Animal ◽  
Reconstruction Algorithm ◽  
Reconstruction Technique ◽  
Reconstruction Method ◽  
Fluorescence Molecular Tomography ◽  
Two Stage ◽  
Quantitative Reconstruction

Fluorescence molecular tomography (FMT) is a promising technique forin vivosmall animal imaging. In this paper, a two-stage reconstruction method based on normalized Born approximation is developed for FMT, which includes two steps for quantitative reconstruction. First, the localization of fluorescent fluorophore is determined byl1-norm regularization method. Then, in the location region of fluorophore, which is provided by the first stage, algebraic reconstruction technique (ART) is utilized for the fluorophore concentration reconstruction. The validity of the two-stage quantitative reconstruction algorithm is testified by simulation experiments on a 3D digital mouse atlas and physical experiments on a phantom. The results suggest that we are able to recover the fluorophore location and concentration.

scholarly journals Comparison of Piezoelectric and Optical Projection Imaging for Three-Dimensional In Vivo Photoacoustic Tomography

2019 ◽  
Vol 5 (1) ◽  
pp. 15 ◽  
Author(s):  
Robert Nuster ◽  
Günther Paltauf
Keyword(s):  
Acoustic Field ◽  
Back Propagation ◽  
Three Dimensional ◽  
Sensor Arrays ◽  
Optical Data ◽  
Acquisition Time ◽  
Photoacoustic Tomography ◽  
Light Illumination ◽  
Optical Setup

Ultrasound sensor arrays for photoacoustic tomography (PAT) are investigated that create line projections of the pressure generated in an object by pulsed light illumination. Projections over a range of viewing angles enable the reconstruction of a three-dimensional image. Two line-integrating arrays are compared in this study for the in vivo imaging of vasculature, a piezoelectric array, and a camera-based setup that captures snapshots of the acoustic field emanating from the sample. An array consisting of 64 line-shaped sensors made of piezoelectric polymer film, which was arranged on a half-cylindrical area, was used to acquire spatiotemporal data from a human finger. The optical setup used phase contrast to visualize the acoustic field generated in the leg of a mouse after a selected delay time. Time-domain back projection and frequency-domain back propagation were used for image reconstruction from the piezoelectric and optical data, respectively. The comparison yielded an about threefold higher resolution for the optical setup and an about 13-fold higher sensitivity of the piezoelectric array. Due to the high density of data in the camera images, the optical technique gave images without streak artifacts, which were visible in the piezo array images due to the discrete detector positions. Overall, both detection concepts are suited for almost real-time projection imaging and three-dimensional imaging with a data acquisition time of less than a minute without averaging, which was limited by the repetition rate of the laser.

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