Journal of X-Ray Science and Technology - Volume 21, issue 1

Authors: Cong, Wenxiang | Shen, Haiou | Cao, Guohua | Liu, Hong | Wang, Ge

Article Type: Research Article

Abstract: In this paper, we presented a new design of x-ray fluorescence CT imaging system. For detecting fuorescence signals of gold nanoparticles in-vivo, multiple spectroscopic detectors are arranged and rotated orthogonal to an excited region of interest so that a localized scan can be acquired with a maximized efficiency. Excitation filtration was employed to minimize the effects of low-energy x-rays and background scattering for lowering radiation dose to the object. Numerical simulations showed that the …radiation dose is less than 300 mGy/second for a complete 30 views tomographic scan; and the sensitivity of 3D fluorescence signal detection is up to 0.2% contrast concentrations of nanoparticles. The x-ray fluorescence computed tomography is an important molecular imaging tool. It can be used directly in samall animal research. It has great translational potential for future clinical applications. Show more

Keywords: X-ray fluorescence computed tomography (XFCT), gold nanoparticles, statistical reconstruction

DOI: 10.3233/XST-130362

Citation: Journal of X-Ray Science and Technology, vol. 21, no. 1, pp. 1-8, 2013

Authors: Khaled, Alia S. | Beck, Thomas J.

Article Type: Research Article

Abstract: Relatively high radiation CT techniques are being widely used in diagnostic imaging raising the concerns about cancer risk especially for routine screening of asymptomatic populations. An important strategy for dose reduction is to reduce the number of projections, although doing so with high image quality is technically difficult. We developed an algorithm to reconstruct discrete (limited gray scale) images decomposed into individual tissue types from a small number of projections acquired over a limited view …angle. The algorithm was tested using projection simulations from segmented CT scans of different cross sections including mid femur, distal femur and lower leg. It can provide high quality images from as low as 5–7 projections if the skin boundary of the cross section is used as prior information in the reconstruction process, and from 11–13 projections if the skin boundary is unknown. Show more

Keywords: Dual energy X-ray (DXA), image reconstruction, discrete tomography, algebraic reconstruction techniques (ART)

DOI: 10.3233/XST-130363

Citation: Journal of X-Ray Science and Technology, vol. 21, no. 1, pp. 9-24, 2013

Authors: Sen Sharma, Kriti | Jin, Xin | Holzner, Christian | Narayanan, Shree | Liu, Baodong | Wang, Dong | Agah, Masoud | Wang, Linbing | Yu, Hengyong | Wang, Ge

Article Type: Research Article

Abstract: High-resolution micro-CT offers 3D non-destructive imaging but scan times are prohibitively large in many cases. Advancements in image reconstruction offer great reduction in number of views while maintaining reconstruction accuracy; yet filtered back projection remains the de facto standard. An extensive study of few-view reconstruction using compressed-sensing based iterative techniques is carried out. Also, a novel 3D micro-CT phantom is proposed, and used for analyzing reconstruction accuracy. Numerical tests, and studies on …real micro-CT data show that if measurement noise in projections is not extremely high, the number of views may be reduced to 1/8^{th} of the typically acquired view numbers. The study motivates the adoption of advanced reconstruction techniques to allow faster scanning, lower dosage, and reduced data size in high-resolution micro-CT. Show more

Keywords: Few-view reconstruction, micro-CT, compressed sensing, TV minimization, SART-TV

DOI: 10.3233/XST-130364

Citation: Journal of X-Ray Science and Technology, vol. 21, no. 1, pp. 25-42, 2013

Authors: Tan, Yiyong | Cao, Zehong | Sajja, Hari Krishna | Lipowska, Malgorzata | Wang, Y. Andrew | Yang, Lily | Jiang, Huabei

Article Type: Research Article

Abstract: PURPOSE: To demonstrate diffuse optical tomography (DOT) corrected fluorescence molecular tomography (FMT) for quantitatively imaging tumor-targeted contrast agents in a 4T1 mouse mammary tumor model. PROCEDURES: In the first set of experiments, we validated our DOT corrected FMT method using subcutaneously injected 4T1 cells pre-labeled with a near-infrared (NIR) Cy 5.5 dye labeled recombinant amino-terminal fragment (ATF) of the receptor binding domain of urokinase plasminogen activator (uPA), which binds to uPA receptor (uPAR) that …is highly expressed in breast cancer tissues. Next, we apply the DOT corrected FMT method to quantitatively evaluate the ability of sensitive tumor imaging after systemic delivery of new uPAR-targeted optical imaging probes in the mice bearing 4T1 mammary tumors. These uPAR-targeted optical imaging probes are ATF peptides labeled with a newly developed NIR-830 dye being conjugated to magnetic iron oxide nanoparticles (IONPs). RESULTS: Our results have shown that DOT corrected FMT can accurately quantify and localize the injected imaging probe labeled 4T1 cells. Following systemic delivery of the targeted imaging nanoprobes into the mice bearing orthotopic mammary tumors, specific accumulation of the imaging probes in the orthotopic mammary tumors was detected in the mice that received uPAR targeted NIR-830-ATF-IONP probes but not in the mice injected with non-targeted NIR-830-mouse serum albumin (MSA)-IONPs. Additionally, DOT corrected FMT also enables the detection of both locally recurrent tumor and lung metastasis in the mammary tumor model 72 hrs after systemic administration of the uPAR-targeted NIR-830-labeled ATF peptide imaging probes. CONCLUSIONS: DOT corrected FMT and uPAR-targeted optical imaging probes have great potential for detection of breast cancer, recurrent tumor and metastasis in small animals. Show more

Keywords: DOT fluorescence tomography targeted contrast agents

DOI: 10.3233/XST-130365

Citation: Journal of X-Ray Science and Technology, vol. 21, no. 1, pp. 43-52, 2013

Authors: Zhao, Xing | Hu, Jing-Jing | Yang, Tao

Article Type: Research Article

Abstract: Iterative reconstruction of high-resolution cone-beam CT data is still a difficult task due to the demand for vast amounts of computer cycles and associated memory. In order to improve the performance of iterative algorithms for cone-beam CT reconstruction, an acceleration approach integrating GPU acceleration, empty space skipping and multi-resolution technique is proposed. The approach divides the reconstructed volume into equally sized blocks, and empty blocks are identified by reconstructing an initial low-resolution …volume and segmenting it with threshold method. Then all non-empty blocks are packed into a new volume, which is initialized by interpolating the low resolution volume and reconstructed at full resolution using iterative algorithms. Finally these non-empty blocks are rearranged to get the reconstructed high-resolution volume. The whole process is implemented in parallel based on GPU. Since only the voxels in non-empty blocks are calculated, the number of considered voxels is greatly reduced, which translates directly into substantial computation, memory requirements and data transfer savings. The method is evaluated by reconstructing images from simulated projection data of phantom and CT datasets. The results indicate that our approach significantly improves the performance of iterative reconstruction while maintaining a high image quality, compared to conventional GPU-based approaches. Show more

Keywords: Iterative reconstruction, computed tomography, image reconstruction, GPU

DOI: 10.3233/XST-130366

Citation: Journal of X-Ray Science and Technology, vol. 21, no. 1, pp. 53-69, 2013

Authors: Abbas, Sajid | Min, Jonghwan | Cho, Seungryong

Article Type: Research Article

Abstract: Computed tomography (CT) is widely used in medicine for diagnostics or for image-guided therapies, and is also popular in industrial applications for nondestructive testing. CT conventionally requires a large number of projections to produce volumetric images of a scanned object, because the conventional image reconstruction algorithm is based on filtered-backprojection. This requirement may result in relatively high radiation dose to the patients in medical CT unless the radiation dose at each view …angle is reduced, and can cause expensive scanning time and efforts in industrial CT applications. Sparse- view CT may provide a viable option to address both issues including high radiation dose and expensive scanning efforts. However, image reconstruction from sparsely sampled data in CT is in general very challenging, and much efforts have been made to develop algorithms for such an image reconstruction problem. Image total-variation minimization algorithm inspired by compressive sensing theory has recently been developed, which exploits the sparseness of the image derivative magnitude and can reconstruct images from sparse-view data to a similar quality of the images conventionally reconstructed from many views. In successive CT scans, prior CT image of an object and its projection data may be readily available, and the current CT image may have not much difference from the prior image. Considering the sparseness of such a difference image between the successive scans, image reconstruction of the difference image may be achieved from very sparsely sampled data. In this work, we showed that one can further reduce the number of projections, resulting in a super-sparse scan, for a good quality image reconstruction with the aid of a prior data. Both numerical and experimental results are provided. Show more

Keywords: Computed tomography (CT), sparse-view CT, total-variation (TV), prior image, compressive sensing (CS), low-dose CT

DOI: 10.3233/XST-130367

Citation: Journal of X-Ray Science and Technology, vol. 21, no. 1, pp. 71-83, 2013

Authors: Liang, Zhi-Xin | Qiang, Yong-Gang | Liao, Yong-Hua | Zhu, Xu-Sheng | Huang, Zheng | Zhang, Xiu-Ping | Wang, Luping

Article Type: Research Article

Abstract: The aim of this in vivo study was to evaluate the feasibility of ^{99m} Tc-labeled cartilage link protein (CLP) probe for the single-photon emission computed tomography (SPECT) of lung cancer. Xenograft mouse model were established from a luciferase expressing cell line derived from a human lung cancer. Bioluminescence imaging (BLI) was carried out prior to ^{99m} Tc-CLP and ^{99m} Tc-methoxyisobutyl isonitrile (MIBI) SPECT scans. The image quality of …^{99m} Tc-CLP scan was validated with BLI and compared with well established ^{99m} Tc-MIBI scan. Results of multimodal imaging analyses suggested that ^{99m} Tc-CLP was a sensitive and reliable SPECT agent for lung cancer imaging. Show more

Keywords: Cartilage link protein, ^{99m}Tc, SPECT, BLI

DOI: 10.3233/XST-130368

Citation: Journal of X-Ray Science and Technology, vol. 21, no. 1, pp. 85-91, 2013

Authors: Li, Heping | Sun, Xiangzhou | Liu, Guihua | Zhang, Yuanyuan | Chu, Jianping | Deng, Chunhua | Zhou, Bo | Chen, Wei | Yang, Jianyong

Article Type: Research Article

Abstract: The nutcracker syndrome is a rare clinic condition associated with severe hematuria and left flank pain due to the entrapment of the left renal vein between the superior mesenteric artery and the aorta. Its diagnostic criteria are not well defined, often causing delayed or misdiagnosis. Although surgical repair has been the standard of care, more recently endovascular stenting of the renal vein has been proposed. We presented six patients (aged 7 to 31 years old; median …age, 16.5 years old) with nutcracker syndrome who were endovascularly managed from June 2002 to July 2011. All patients underwent laboratory test and computed tomography (CT) or ultrasound examination before and after endovascular procedures. Self-expandable stents were successfully placed in all cases. The diameter of the left renal vein at aorto-superior mesenteric artery portion significantly increased from 1.88 ± 0.95 mm pre-procedure to 5.24 ± 0.61 mm post-procedure (p< 0.01). Left renal vein pressure significantly decreased from 11.00 ± 4.34 mmHg pre-procedure to 6.00 ± 2.55 mmHg post-procedure (p< 0.01). Severe gross hematuria completely subsided within 2 months to 6 months and left flank pain completely subsided within 7 days to 1 month after treatment. Endovascular therapy provides an alternative therapy with satisfactory long-term clinical and imaging results for symptomatic patients with nutcracker syndrome. Show more

Keywords: Nutcracker syndrome, endovascular stent, hematuria

DOI: 10.3233/XST-130356

Citation: Journal of X-Ray Science and Technology, vol. 21, no. 1, pp. 95-102, 2013

Authors: Hsiao, Ya-Chuan | Tsai, I-Lun | Kuo, Chin-Tzu | Yang, Tsung-Lin

Article Type: Research Article

Abstract: As a rare cause of microbial keratitis, microsporidial keratitis (MK) is first described in a patient with acquired immunodeficiency syndrome. As increased use of topical steroid creates a localized immunosuppressive environment of the eyes, MK occurs more commonly than expected in immunocompetent patients nowadays. Owing to initial insidious growth of pathogens and nonspecific ocular symptoms of infected patients, its frequent misdiagnosis has posed a major clinical challenge in recent decades. Without appropriate …treatments, MK can progress deeply into corneal stroma, anterior and posterior segments, subsequently deteriorating vision severely and ultimately requiring corneal transplant. Related risk factors for the occurrence of MK in immunocompetent individuals include contact lens wear, topical steroid use, previous corneal trauma, and a history of laser refractive surgery. The conventional standard of MK diagnosis is based on a tissue biopsy by superficial corneal scrapping. In vivo confocal laser scanning microscopy can obtain images through the cornea in a plane paralleling to the vertical axis. This approach provides an effective method of identifying tissue layers that correspond to corneal histologic structures. This current study investigates the efficacy of \textit{in vivo} confocal laser scanning microscopy in diagnosing MK in immunocompetent patients. The clinical presentations of enrolled patients, including features of slit lamp biomicroscopy and the histopathological results of corneal scrapping, were described. In these patients, the confocal microscopy identified multiple small intracellular hyper-reflective dots in the cytoplasm of corneal epithelial cells and stromal keratocytes. Additionally, the confocal microscopic images clearly revealed the enhanced cytoplasm of cell with intracellular round hyper-reflective dots. The size and morphology of hyper-reflective dots were compatible with the spores of microsporidia found in corneal tissue. Moreover, vision recovered after topical use of antimicrobial medicine. This observation suggests that in vivo confocal laser scanning microscopy provides a rapid, non-invasive, and high resolution scheme for diagnosing MK. In addition to diminishing the risk of secondary infection from epithelial defect created by superficial debridement, this approach facilitates early diagnosis and appropriate treatments. Furthermore, from a series of images taken during the clinical courses, this method is highly promising for use in monitoring treatment effects and identifying the recurrence of MK. Show more

Keywords: Microsporidial keratitis, confocal microscopy, microsporidial keratoconjunctivitis, corneal scrapping

Citation: Journal of X-Ray Science and Technology, vol. 21, no. 1, pp. 103-110, 2013

Authors: Song, Lujie | Xie, Minkai | Zhang, Yuanyuan | Xu, Yuemin

Article Type: Research Article

Abstract: Urethral injures, pelvic trauma, and certain congential abnormalities in male can often cause urethral strictures and scarring. Adequate and accurate imaging diagnosis of urethral strictures is critial to select a surgical approach. Although urethrography is commonly used in evaluating male urethral injury and strictures, its limitation is that the contrast offers images only at the urethral lumen but not of the periurethral structures. Sonourethrography (SUG) has the ability to define the periurethral …tissues and without the radiation exposure, the degree of periurethral fibrosis can be shown with a view to guiding surgery especially in bulbar urethra. Computed tomography (CT) urethrography has the advantage of examining patients only in one position, and by generating three-dimensional images; it can accurately measure the stricture length. Magnetic resonance imaging (MRI) provide useful information in certain clinical situations, particularly posterior urethral trauma and in the evaluation of the periurethral soft tissues. However, both CT and MRI are relative high cost. The selection of imaging methods should depend on the etiology, sites, patient's general condition and the type of urethral injury, using a rational combination of different imaging methods can improve the accuracy of diagnosis for traumatic urethral strictures. Show more

Keywords: Retrograde urethrography (RUG), voiding urethrography (VCUG), sonourethrography (SUG), computed tomography (CT) urethrography, Magnetic resonance imaging (MRI), male traumatic urethral strictures, diagnosis

DOI: 10.3233/XST-130358

Citation: Journal of X-Ray Science and Technology, vol. 21, no. 1, pp. 111-123, 2013

Authors: Xue, Boxin | Zang, Yachen | Zhang, Yuanyuan | Yang, Dongrong | Gao, Jie | Sun, Chuanyang | Cui, Yong | Zhu, Jin | Liu, Xiaolong | Shan, Yuxi

Article Type: Research Article

Abstract: The most recent advance in laser treatment of benign prostatic hyperplasia (BPH) is the introduction of a high-performance system (HPS) 120-W laser. The HPS laser beam at a wavelength of 532~nm is highly absorbed by oxyhemoglobin in the tissue and maintains focus with negligible divergence up to 3 mm from the fiber and with limited divergence at 5 mm. This study is designed to evaluate the three-year clinical efficacy and safety of photoselective vaporization of the …prostate (PVP, n=100 cases) with GreenLight HPS laser compared with transurethral resection of the prostate (TURP, n=100 cases) for treatment of BPH. The results showed that the mean operating time, catheterization time and admission time were significantly shorter in the PVP group, respectively. There were dramatic improvements in International Prostate Symptom Score (IPSS), quality of life (Qol), maximum flow rate (Qmax) and postvoid residual (PVR) compared with preoperative values and the degree of improvements was comparable in both groups. The intraoperative complications were lower in PVP group. In summary, PVP is an effective technique in patients with BPH, when compared to TURP, producing equivalent improvements in IPSS, Qmax, Qol and PVR with the advantages of markedly reduced catheterization time, admission time and adverse events. Show more

Keywords: Benign prostatic hyperplasia, laser therapy, GreenLight HPS laser, transurethral resection of the prostate

DOI: 10.3233/XST-130359

Citation: Journal of X-Ray Science and Technology, vol. 21, no. 1, pp. 125-132, 2013

Authors: Sa, Ying Long | Xu, Yue Min | Feng, Chao | Ye, Xu Xiao | Song, Lu Jie

Article Type: Research Article

Abstract: To evaluate the value of three-dimensional spiral computed tomography/cysto-urethrography (CTCUG) in diagnosing posterior urethral strictures associated with urethrorectal fistulas (URF). Between June 2008 and March 2012, 38 patients with posterior urethral strictures associated with URFs were examined by CTCUG, retrograde urethrography (RUG) and cysto-urethrography (CUG). Urethral reconstruction was undertaken and URFs were surgically repaired in all patients. The length of the urethral defect, location and size of URFs were recorded. Data from …radiological examinations were compared with surgical findings. No statistically significant difference was found in the length of stricture measured using CTCUG (4.31 ± 2.28 cm) or conventional urethrography (4.02 ± 3.12 cm; p > 0.05), However, the accuracy in determining the location of the stricture was higher with CTCUG (93.12%) than with conventional urethrography (70.59%; p < 0.05). CTCUG identified URFs in all 38 patients (100%), whereas URFs were only observed in 27 patients (71%) using conventional urethrography. In conclusion, CTCUG was more accurate, safer and provided more details of URFs and urethral defects than conventional urethrography in patients with posterior urethral strictures associated with URFs. Show more

Keywords: Posterior urethral strictures, urethrorectal fistulas, CT, image analysis

DOI: 10.3233/XST-130360

Citation: Journal of X-Ray Science and Technology, vol. 21, no. 1, pp. 133-139, 2013

Authors: Guo, Yan | Liu, Guihua | Yang, Dong | Sun, Xiangzhou | Wang, Huanjun | Deng, Chunhua | Zhang, Yuanyuan | Feng, Shi-Ting

Article Type: Research Article

Abstract: This study aims to analyze magnetic resonance imaging (MRI) features of ejaculatory duct obstruction, and to provide an accurate diagnostic imaging approach for surgical planning of minimally invasive procedures treating ejaculatory duct obstruction. A total of 18 men with ejaculatory duct obstruction were enrolled in the study. The patients were admitted to our hospital and had undergone MRI examination and surgical treatment from January 2003 to February 2011. The data was collected by searching keywords …('ejaculatory duct obstruction') from our PACS. Patients suspected having ejaculatory duct obstruction according to the manifestations through MRI examinations and further being confirmed by surgery were included. The MRI features of ejaculatory duct obstruction in these patients were summarized. Five cases with ejaculatory duct cysts were detected by MRI, ranging in size from 4 mm × 4 mm × 7 mm to 4 mm × 4 mm × 9 mm and located in the paramedian line; ejaculatory duct dilation near the median line, with the internal diameter ranging from 5 mm to 30 mm was detected in nine cases; and among thirteen cases who underwent both non-contrast enhanced and contrast enhanced MRI scanning, significant enhancement of the wall of the ejaculatory duct on enhanced scanning was observed in three cases. Mullerian duct cysts complicated with dilation of the ejaculatory duct and seminal vesicles were detected in four cases; in these cases, the cysts were located in the median line, ranging in size from 4 mm × 5 mm × 6 mm to 34 mm × 35 mm × 44 mm, tear-drop appearance, with the tip pointing toward the area of the seminal colliculus. Findings of MRI were confirmed by the observations during the surgery. MRI is more accurate at displaying the ejaculatory duct. We recommend that ejaculatory duct diameter of > 2 mm can be used as a diagnostic criterion with MRI image analyses for ejaculatory duct dilation. Show more

Keywords: Sterilitas virilis, ejaculatory duct obstruction, transurethral resection, MRI

DOI: 10.3233/XST-130361

Citation: Journal of X-Ray Science and Technology, vol. 21, no. 1, pp. 141-146, 2013