Compressive sampling based interior reconstruction for dynamic carbon nanotube micro-CT.

In the computed tomography (CT) field, one recent invention is the so-called carbon nanotube (CNT) based field emission x-ray technology. On the other hand, compressive sampling (CS) based interior tomography is a new innovation. Combining the strengths of these two novel subjects, we apply the interior tomography technique to local mouse cardiac imaging using respiration and cardiac gating with a CNT based micro-CT scanner. The major features of our method are: (1) it does not need exact prior knowledge inside an ROI; and (2) two orthogonal scout projections are employed to regularize the reconstruction. Both numerical simulations and in vivo mouse studies are performed to demonstrate the feasibility of our methodology.

Extracolonic findings at virtual colonoscopy: an important consideration in asymptomatic colorectal cancer screening.

BACKGROUND: Virtual colonoscopy has been evaluated for use as a colorectal cancer screening tool, and in prior studies, it has been estimated that the evaluation of extra-colonic findings adds $28-$34 per patient studied. METHODS: As an ancillary study to a prospective cohort study comparing virtual colonoscopy to conventional colonoscopy for colorectal cancer detection, the investigators retrospectively determined the number and estimated costs of all clinic visits, imaging and laboratory studies, and medical procedures that were generated as a direct result of extra-colonic findings at virtual colonoscopy. RESULTS: We enrolled 143 subjects who underwent CTC followed by conventional colonoscopy. Data were available for 136 subjects, and 134 (98%) had at least one extra-colonic finding on CT. Evaluation of extra-colonic findings was performed in 32 subjects (24%). These subjects underwent 73 imaging studies, 30 laboratory studies, 44 clinic visits, 6 medical procedures, and 44 new or return outpatient visits over a mean of 38 months following the CTC. The most common findings causing further evaluation were lung nodules and indeterminate kidney lesions. No extra-colonic malignancies were found in this study. A total of $33,690 was spent in evaluating extra-colonic findings, which is $248 per patient enrolled. CONCLUSIONS: The cost of the evaluation of extra-colonic findings following virtual colonoscopy may be much higher in actual practice than is suggested by prior studies. This will impact the cost-effectiveness of using virtual colonoscopy for asymptomatic colorectal cancer screening and underscores the importance of standardizing the reporting of extra-colonic findings to encourage appropriate follow-up.

Voiding pattern analysis as a surrogate for cystometric evaluation in uroplakin II knockout mice.

PURPOSE: Previous study has shown that the absence of uroplakin II can cause urinary tract dysfunction, including vesicoureteral reflux and renal abnormalities, as well as micturition pattern changes. We developed a simple surrogate measure of bladder function using ultraviolet visualization of urinary voiding patterns in a uroplakin II knockout mouse animal model. MATERIALS AND METHODS: Three male and 3 female WT mice, and 3 male and 3 female uroplakin II knockout mice were evaluated by cystometric analysis and voiding pattern markings. Voiding pattern markings were graded by independent observers on a scale of 1 to 5 according to the degree of dispersion of voided urine. Statistical analysis was then used to correlate voiding dispersion grades with cystometric parameters in the same mice. RESULTS: The degree of dispersion of voiding pattern markings correlated with several measures of bladder function. Specifically the Pearson correlation coefficients for the observed voiding patterns highly correlated with baseline pressure, threshold pressure and intermicturition pressure measurements made during conscious cystometry in these mice (p <0.05). CONCLUSIONS: Ultraviolet visualization of urinary voiding patterns of mice correlated well with certain measures of standard cystometric evaluations. As such, this method provides a simple, noninvasive method of evaluating mouse bladder function. Implementation of this methodology, which can potentially be automated for high throughput analysis, can accelerate the development of novel therapy for certain important aspects of bladder disease/dysfunction.

Quantification of biopolymer filament structure.

The quantitative analysis of a polymer network is important for understanding its role in biological function. We developed a Matlab program to recognize and segment filaments in a 2-D image, and measure and describe the structure. Our algorithm improved the speed of the Lichtenstein Fiberscore segmentation algorithm by using matrix convolutions, compared filament length by the algorithms of Kulpa, Lichtenstein, and Kimura, and measured the number of branchpoints and Euler number. A user interface was added to easily manipulate algorithm parameters, select images, and visualize results. We used the program to compare the DNA biopolymer network of cystic fibrosis (CF) sputum with mucus from patients without respiratory problems. We also examined an image of fibrin. The images were taken with a laser scanning confocal microscope after staining the specimens with Yo-Yo-1. Computation using matrix convolutions reduced the execution time (Pentium III) of a 512 x 512 TIF image from 18 min to 15s. The Kimura length estimation appeared best at describing filament length because it varied least with filament orientation. The image of CF sputum showed increased filament length, more branchpoints, and more negative Euler number compared to the normal sample. These quantitative descriptions of the network can be correlated to material, mechanical, diffusion, or flow properties, physiological processes, or therapy.