A graphical user interface for automatic image registration software designed for radiotherapy treatment planning

A graphical user interface for automated 2- or 3-dimensional image registration in dental treatment recovery planning: the DentIR application

OBJECTIVES

Cone-beam computed tomography (CBCT) scans enable quantification of interproximal bone loss after implant procedures in dental patients. In order for this quantification to be accurate, software is typically used to manipulate image sets captured before and after implantation to obtain their exact registration (i.e., alignment). However, no affordable CBCT image registration software is currently available for dental applications. Thus, the aim of the present study was to develop a freely available graphical user interface, called DentIR, that automates 2-dimensional (2-D) or 3-D image registration for use in planning dental treatment.

METHODS

The DentIR app was designed using the MATLAB environment, downloaded to a desktop personal computer (PC and Mac), and tested for its ease of use and alignment accuracy in the absence of the MATLAB environment.

RESULTS

The DentIR app enabled previewing of the CBCT images in 3-D to allow for filtering of each frame to reduce noise and blurring before registration. The 2-D or 3-D registration was tested with four transformation methods. The accuracy of each method was assessed by comparing the mean squared error and the peak signal-to-noise ratio values that were provided by the DentIR app. The registered images could be saved as Portable Network Graphics (PNG) images.

CONCLUSIONS

The free, user-friendly DentIR app was easily downloadable to Mac or PC platforms. It provided accurate image registration to aid in the planning of dental treatment. Future updates of the DentIR app include adding the ability to register more than two images at once, enhancing image editing options and enabling registration of a cropped portion of the image for more in-depth analyses.

Effect of practice management softwares among physicians of developing countries with special reference to Indian scenario by Mixed Method Technique

Introduction:

Currently, many cheaper “practice management software” (PMS) are available in developing countries including India; despite their availability and benefits, its penetration and usage vary from low to moderate level, justifying the importance of this study area.

Materials and Methods:

First preferred reporting items for systematic-review and meta-analysis (2009) guidelines were considered; followed by an extensive systematic-review of available studies in literature related to developing countries, on key search term from main abstracting databases: PubMed, EMBASE, EBSCO, BIO-MED Central, Cochrane Library, world CAT-library till 15 June 2014; where any kind of article whether published or unpublished, in any sort or form or any language indicating the software usage were included. Thereafter, meta-analysis on Indian studies revealing the magnitude of usage in Indian scenario by Open Meta-(analyst) software using binary random effects (REs) model was done. Studies from developed countries were excluded in our study.

Results:

Of 57 studies included in a systematic review from developing countries, only 4 Indian studies were found eligible for meta-analysis. RE model revealed although not-significant results (total participants = 243,526; range: 100–226,228, overall odds ratio = 2.85, 95% confidence interval = P < 0.05 and tests for heterogeneity: Q [df = 3] = 0.8 Het. P = 0.85). The overall magnitude of usage of PMS on Indian physicians practice was however found between 10% and 45%.

Conclusion:

Although variable and nonsignificant effect of usage of PM software on practice of physicians in developing countries like India was found; there is a need to recognize the hidden potential of this system. Hence, more in-depth research in future needs to be done, in order to find a real impact of this system.

Cardiac image integration implications for atrial fibrillation ablation

Cardiac image registration using computed tomography (CT), magnetic resonance imaging (MRI), ultrasound, and fluoroscopy is currently being investigated and clinically used for atrial fibrillation (AF) ablation. Cardiac image registration, in the context of left atrium, is intermodal, with the acquired image and the real-time reference image residing in different image spaces, and involves optimization, where one image space is transformed into the other. Geometry-based methods, which include using fiducial points and/or surface-based techniques, are usually used for cardiac image registration. During fiducial point registration, fiducial points are either external skin markers or manually determined by marking anatomical landmarks, using mapping catheters. Usually, a minimum of three non collinear points are needed for optimal registration. Recently, a catheter placed inside the coronary sinus has also been used as a fiducial marker for the purpose of registration. During surface registration, the process involves characterizing surfaces in each of the images and deriving the best transformation between them. Unlike rigid body registration, such as has been extensively used in imaging the brain, cardiac image registration is unique and challenging. In addition to the errors inherent in intermodal registration, such as errors in pixel and voxel dimension and errors due to fiducial point selection, there are errors specific to cardiac image registration, i.e., errors due to cardiac motion during the cardiac cycle and due to respiration. This review addresses the basic principles of registration and the inherent registration errors as they relate to cardiac imaging and registration.

The role of diffusion-weighted imaging in the differential diagnosis of intracranial cystic mass lesions: a report of 147 lesions

BACKGROUND

The objective of this study is to evaluate the sensitivity and specificity of DWI in differentiating brain abscesses from other intracranial cystic lesions.

METHODS

One hundred fifteen patients with 147 cystic lesions (mean age, 26.4 year) were prospectively studied with DWI on a 1.5-T magnetic resonance imaging. Lesions appearing hyperintense on DWI with the ADC values of lower than 0.9 +/- 0.13 x 10(-3) mm(2)/s (mean +/- SD) were considered as brain abscess, whereas hypointense lesions on DWI with the ADC values 2.2 +/- 0.9 x 10(-3) mm(2)/s were categorized as nonabscess cystic lesions.

RESULTS

Ninety-three of 97 brain abscess lesions were hyperintense on DWI, with significantly low (P = .0001) ADC value (0.87 +/- 0.05 x 10(-3) mm(2)/s) (mean +/- SEM), compared with 48 nonabscess lesions (2.89 +/- 0.05 x 10(-3) mm(2)/s). Four of 97 brain abscess lesions in 65 patients were false negative, and 2 of 50 nonabscess lesions in 50 patients were false positive for the diagnosis of brain abscess. The ADC value of the tumor cysts (2.9 +/- 0.05 x 10(-3) mm(2)/s) was significantly lower (P = .02) compared with benign cysts and neurocysticercosis (3.2 +/- 0.05 x 10(-3) mm(2)/s) among nonabscess group. The sensitivity of DWI for the differentiation of brain abscesses from nonabscesses was 96%; specificity, 96%; positive predictive value, 98%; negative predictive value, 92%; and accuracy of the test, 96%.

CONCLUSIONS

Diffusion-weighted imaging has high sensitivity and specificity for the differentiation of brain abscess from other nonabscess intracranial cystic lesions.

Comparison of the magnetization transfer ratio and fluid-attenuated inversion recovery imaging signal intensity in differentiation of various cystic intracranial mass lesions and its correlation with biological parameters

PURPOSE

To compare the signal intensity on the fluid attenuated inversion recovery (FLAIR) sequence and magnetization transfer ratios (MTRs) for the differentiation of abscesses from non-abscess cystic brain lesions, and to correlate these MR parameters with the viscosity, viable cell density and total protein concentration of the cystic fluid.

MATERIALS AND METHODS

Signal intensity on FLAIR and MTRs from the cystic cavity of lesions were calculated from 33 patients (brain abscess (N = 12) and non-abscess (N = 21)). The fluid from the lesion was aspirated at the time of surgery, and the viscosity, viable cell density, and total protein concentration were measured.

RESULTS

Signal intensity on FLAIR correlated significantly with the total protein concentration in abscess (r = 0.60, P < 0.05) and non-abscess lesions (r = 0.41, P < 0.05). However, there was no significant difference (P > 0.05) in the FLAIR signal intensity of the abscess (318.8 +/- 75) and non-abscess group (258 +/- 47). The MTR of the brain abscesses (13 +/- 0.95) was significantly higher (P < 0.05) than that of the non-abscess group (3.5 +/- 0.3). A significant correlation was observed between MTR and viscosity (r = 0.75, P < 0.05), total protein concentration (r = 0.60, P < 0.05), and cell density (r = 0.70, P < 0.05) in brain abscess, and viscosity (r = 0.81, P < 0.05) and total protein concentration (r = 0.41, P < 0.05) in non-abscess lesions.

CONCLUSION

It is possible to differentiate brain abscesses from non-abscess cystic lesions using MT imaging. The MTR correlates significantly with the viscosity, viable cell density, and total protein concentration in brain abscess, and with viscosity and total protein concentration in non-abscess lesions. FLAIR signal intensity correlates significantly only with the total protein concentration in abscess and non-abscess lesions.

Three-dimensional reconstruction of registered and fused Chinese Visible Human and patient MRI images

Radiological images are commonly used as important tools in medical diagnoses and treatment. Different modalities of medical images provide uniquely different content. Hence, it is natural and desirable to combine different image modalities to obtain additional new information to enhance clinical assessment. However, given the current technology, radiological images are not always sufficiently informative to permit diagnosis and treatment. In order to address this problem, we fused selected portions of the Chinese Visible Human (CVH) dataset with MRI images from a patient. Specifically, we segmented the caudate nucleus, the lentiform nucleus, and the thalamus in the CVH dataset and then registered and fused this dataset with corresponding MRI images using both rigid and nonrigid registration techniques. After rigid and nonrigid registration, the CVH and MRI images largely coincided with each other. The shape, relationship, and position of focal areas and neural structures were clearly displayed. Using volume and surface rendering, these images were three-dimensionally reconstructed to display the neural structures of interest within the brain. These structures can be rotated at will and observed from different angles. Our research indicates that the fusion of CVH and patients' MRI images can enhance the amount of neural information available to physicians and lay a foundation for the clinical use of the CVH dataset.

Cytotoxic edema is responsible for raised intracranial pressure in fulminant hepatic failure: in vivo demonstration using diffusion-weighted MRI in human subjects

It is not clear whether cerebral edema in fulminant hepatic failure is predominantly vasogenic or cytotoxic, though cytotoxic edema due to astrocyte swelling is more likely. Diffusion-weighted magnetic resonance imaging can differentiate vasogenic from cytotoxic edema. We performed diffusion-weighted imaging in patients with fulminant hepatic failure to clarify the issue by measuring apparent diffusion coefficient, which quantifies movement of water molecule across cell membrane. Seven patients with fulminant hepatic failure underwent conventional and diffusion-weighted magnetic resonance imaging. Apparent diffusion coefficient was measured in four cortical areas and 12 deep white and gray matter regions in both cerebral hemispheres. Thirteen healthy subjects served as controls. The apparent diffusion coefficient values in patients and controls were compared using Wilcoxon signed rank test. Two patients who survived underwent repeat imaging using same protocol. Patients with FHF had significantly lower apparent diffusion coefficient in all cortical and deep white and gray matter regions of interest compared to controls (p < 0.001), suggesting cytotoxic cell swelling. In two survivors with repeat imaging, one showed complete resolution while the changes persisted in the other, suggesting ischemic injury. Cerebral edema in fulminant hepatic failure is predominantly due to cytotoxic edema.