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Introduction: Dynamic susceptibility contrast (DSC) perfusion weighted (PW)-MRI can aid in differentiating treatment related abnormalities (TRA) from tumor progression (TP) in post-treatment glioma patients. Common methods, like the 'hot spot', or visual approach suffer from oversimplification and subjectivity. Using perfusion of the complete lesion potentially offers an objective and accurate alternative. This study aims to compare the diagnostic value and assess the subjectivity of these techniques. Methods: 50 Glioma patients with enhancing lesions post-surgery and chemo-radiotherapy were retrospectively included. Outcome was determined by clinical/radiological follow-up or biopsy. Imaging analysis used the 'hot spot', volume of interest (VOI) and visual approach. Diagnostic accuracy was compared using receiving operator characteristics (ROC) curves for the VOI and 'hot spot' approach, visual assessment was analysed with contingency tables. Inter-operator agreement was determined with Cohens kappa and intra-class coefficient (ICC). Results: 29 Patients suffered from TP, 21 had TRA. The visual assessment showed poor to substantial inter-operator agreement (κ = -0.72 – 0.68). Reliability of the 'hot spot' placement was excellent (ICC = 0.89), while reference placement was variable (ICC = 0.54). The area under the ROC (AUROC) of the mean- and maximum relative cerebral blood volume (rCBV) (VOI-analysis) were 0.82 and 0.72, while the rCBV-ratio ('hot spot' analysis) was 0.69. The VOI-analysis had a more balanced sensitivity and specificity compared to visual assessment. Conclusions: VOI analysis of DSC PW-MRI data holds greater diagnostic accuracy in single-moment differentiation of TP and TRA than 'hot spot' or visual analysis. This study underlines the subjectivity of visual placement and assessment. [ABSTRACT FROM AUTHOR]

Volumes of interest (VOI) are commonly assigned to image stacks generated from micro-computed tomography to specify areas for bone quantification. However, the size of the VOI can impact the values obtained for trabecular bone parameters. This study aims to investigate the effect of VOI size by applying VOIs of four different diameters (10%, 15%, 20% and 30% of the antero-posterior width). Ten juvenile right distal femora were included, aged from pre-natal to three years. Smaller VOIs were placed within the largest VOI, with multiple locations used for the same VOI size. The observed parameters included bone volume fraction (BV/TV), trabecular bone thickness (Tb.Th), separation (Tb.Sp), number (Tb.N), degree of anisotropy by mean intercept length (DA.MIL) and star volume distribution (DA.SVD). Statistically significant differences between VOI sizes were found for Tb.Sp, Tb.N, DA.MIL and DA.SVD. A possible effect of localized variation was found due to significantly different values for Tb.Th between VOI locations. The effect related to VOI geometry was reflected by DA.MIL and DA.SVD as no significant difference was found between locations. The minimum diametric strut quantity (DSQ, diameter multiplied by Tb.N) of 4 can be implied based on the zero DA.SVD value found in particular VOIs. [ABSTRACT FROM AUTHOR]

This paper explores a technique for visually/diagnostically lossless coding in the wavelet domain to effectively compress the three-dimensional medical image data. The quantisation module based on Just Noticeable Distortion (JND) for wavelets guarantees the visual quality in the reconstructed data. This method has been further extended to present the Volume of Interest (VOI) based technique that enables to preserve the quality of the diagnostically significant VOI region. The proposed method tested on several datasets outperforms the state-of-the-art methods. Apart from the conventional quality metric, Human Visual System (HVS) based quality metrics are also used to evaluate the visual quality of the reconstructed image. A subjective and objective evaluation carried out for VOI based coder shows that the quality-compression needs of the medical community are well addressed. [ABSTRACT FROM AUTHOR]

Objective To assess the prediction value of a nomogram model constructed by gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced MRI signatures combined with the mean T1 relaxation time of tumor and the peritumor dual-region for microvascular invasion of hepatocellular carcinoma.Methods Seventy-two patients with solitary hepatocellular carcinoma (HCC) underwent preoperative Gd-EOB-DTPA-enhanced MRI and curative liver resection in our hospital from January 2019 to September 2022.The patients were divided to two groups with (MVI+, 23) and without (MVI-, 49) microvascular invasion (MVI).The clinical information and MRI were retrospectively analyzed.Multivariate logistic analyses were used to screen out independent risk factors that could predict MVI.Two models were constructed with (T1 model) or without (no T1 model) inclusion of T1 relaxation time and their diagnostic efficacy was evaluated using a subject operating curve, calibration curve and decision curve.Net reclassification improvement (NRI) and integrated discrimination improvement (IDI) were used to evaluate the differences between models and to select the optimal model to construct a nomogram.Results There was significant difference between the MVI-and MVI+groups in tumor margin (P＜0.001), tumor capsule (P=0.010), mosaic architecture (P=0.015), peritumoral enhancement in the arterial phase (P=0.018), peritumoral hypointensity in the hepatobiliary phase (P＜0.001), preoperative alpha-fetoprotein (P=0.003), tumor size (P＜0.001), T1 P+tumor (P=0.001), T1 E+tumor (P=0.009), T1 P+10 mm (P=0.014), T1 P+tumor+10 mm (P＜0.001), T1 E+tumor+10 mm (P=0.001), T1 P+tumor+20 mm (P=0.001), T1 E+tumor+20 mm (P=0.002) and T1D%tumor+20 mm (P=0.035).Multivariate logistic regression analysis showed that tumor margin (P=0.005;OR=10.391), peritumoral enhancement in the arterial phase (P=0.020;OR=7.729), peritumoral hypointensity in the hepatobiliary phase (P=0.003;OR=12.891) and T1 P+tumor+10 mm (P=0.026;OR=1.006)were independent risk factors for the occurrence of MVI in hepatocellular carcinoma.The areas under the ROC curves were 0.906 (0.840-0.973) for the no T1 model and 0.928 (0.873-0.984) for the T1 model.The calibration curve showed that the predicted probability was in good agreement with the MVI+/MVI-probability of the pathological results.The decision curve analysis displayed a more satisfactory net benefit rate of T1 model than that of no T1 model.The T1 model increased NRI by 0.4366 and IDI by 0.0689 compared to the no T1 model.Conclusion Gd-EOB-DTPA-enhanced MRI can be used to predict HCC MVI effectively.The combination of T1 P+tumor+10 mmin the nomogram model further improves the predictive efficacy of hepatocellular carcinoma MVI. [ABSTRACT FROM AUTHOR]

Objective To evaluate the relationship between the volume of liver lesions and the clinical severity and prognosis of pyrrolidine alkaloid-related hepatic sinusoidal obstruction syndrome (PA-HSOS). Methods The clinical data of 45 patients with PA-HSOS (12 with histological confirmation) in our hospital from April 2015 to March 2020 were reviewed. The volume of heterogeneous hypoattenuation on CT was measured and correlated with the clinical severity using one-way analysis of variance. The Kaplan-Meier method was used to calculate the survival rate and the influence of risk factors on survival was determined using multivariate Cox regression analysis. Results The main symptoms were abdominal distension (100%), ascites (93.3%), and jaundice (71.1%). CT findings included varying degrees of liver swelling with heterogeneous reduction of parenchymal density (92.1%) and patchy contrast enhancement in the portal vein and delay phases (100%). The lesion volume and ratio of lesion to liver volumes were positively correlated with the clinical severity. The median follow-up time was 21 months, and the 1-year survival rate was 72.5%. Multivariate Cox analysis showed that the ratio of lesion to liver volumes (P=0.012) and total bilirubin level (P =0.005) were the main risk factors affecting patient survival. Conclusion The volume of liver lesions on CT is positively correlated with the clinical severity. The ratio of lesion to liver volumes and the total bilirubin level are reliable predictors of patient survival in PA-HSOS. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the impact of applying three different volume of interests (VOIs) in ADC map-based radiomic analysis and compare their diagnostic performance in the differentiation of uterine sarcoma and atypical leiomyoma.Procedures: Seventy-eight patients (29 uterine sarcomas, 49 uterine leiomyomas) imaged with pelvic magnetic resonance imaging (MRI) prior to surgery were included in this retrospective study. Manually, segmentations of VOIs covered three different regions on apparent diffusion coefficient (ADC) maps: (1) tumor, (2) tumor and small piece of surrounded tissue, and (3) whole uterus. Texture and non-texture features were extracted from each VOI. The 0.623 + bootstrap method and the area under the receiver-operating characteristic curve (AUC) were used to select the features. Twenty logistic regression models (orders of 1-20) based on different combination of image features were built for each way of image segmentation.Results: For the first VOI region, model 18 with 18 features yielded the highest AUC of 0.830, sensitivity of 76.0 %, specificity of 73.2 %, and accuracy of 73.9 %. For the second VOI region, model 17 with 17 features yielded the highest AUC of 0.853, sensitivity of 75.5 %, specificity of 75.5 %, and accuracy of 76.8 %. For the third VOI region, model 20 with 20 features yielded the highest AUC of 0.876, sensitivity of 76.3 %, specificity of 84.5 %, and accuracy of 82.4 %.Conclusions: Radiomic model based on features extracted from VOI that covered the whole uterus had the best diagnostic performance. Adopting VOI contained more image information that was useful in improving diagnostic performance of radiomic model. [ABSTRACT FROM AUTHOR]

Highlights • This paper presents a multi-channel biomedical data and information computing and visualization system that can efficiently process large histological image acquired from high-resolution microscopes. • Our system can dynamically display a volume of interest and extract tissue information using a new layer-based data navigation and exploration scheme. • During data exploring, the actual resolution of the data loaded can be dynamically determined and updated. The large data rendering is synchronized in four display windows at each data layer, where 2D textures are extracted from the Medical volume and mapped onto the displayed clipping planes with arbitrary orientations. • To test the efficiency and scalability of this system, we performed extensive evaluations using different hardware systems and large histological color datasets and experimental results demonstrated a solid performance. • Our system can deliver interactive data navigation speed and display detailed imaging information in real time, which is beyond the capability of commonly available biomedical data exploration software platforms. • Taking advantage of both CPU (central processing unit) main memory and GPU (graphics processing unit) graphics memory, this software platform can efficiently compute, process and visualize very large biomedical data and enhance data information. Abstract Background and objective Modern microscopes can acquire multi-channel large histological data from tissues of human beings or animals, which contain rich biomedical information for disease diagnosis and biological feature analysis. However, due to the large size, fuzzy tissue structure, and complicated multiple elements integrated in the image color space, it is still a challenge for current software systems to effectively calculate histological data, show the inner tissue structures and unveil hidden biomedical information. Therefore, we developed new algorithms and a software platform to address this issue. Methods This paper presents a multi-channel biomedical data computing and visualization system that can efficiently process large 3D histological images acquired from high-resolution microscopes. A novelty of our system is that it can dynamically display a volume of interest and extract tissue information using a layer-based data navigation scheme. During the data exploring process, the actual resolution of the loaded data can be dynamically determined and updated, and data rendering is synchronized in four display windows at each data layer, where 2D textures are extracted from the imaging volume and mapped onto the displayed clipping planes in 3D space. Results To test the efficiency and scalability of this system, we performed extensive evaluations using several different hardware systems and large histological color datasets acquired from a CryoViz 3D digital system. The experimental results demonstrated that our system can deliver interactive data navigation speed and display detailed imaging information in real time, which is beyond the capability of commonly available biomedical data exploration software platforms. Conclusion Taking advantage of both CPU (central processing unit) main memory and GPU (graphics processing unit) graphics memory, the presented software platform can efficiently compute, process and visualize very large biomedical data and enhance data information. The performance of this system can satisfactorily address the challenges of navigating and interrogating volumetric multi-spectral large histological image at multiple resolution levels. [ABSTRACT FROM AUTHOR]

ABSTRACT Bone density measurements using computed tomography (CT) instead of dual-energy X-ray absorptiometry (DEXA) are currently of great interest in human and veterinary medical research as it would be beneficial to use CT scans obtained for other indications also for determining bone density. For Hounsfield units (HU) measured with CT in specific regions of interests (ROIs) in one or several slice/s a correlation with bone mineral density (BMD) measured by DEXA in humans and dogs of between 0.44 and 0.77 is reported in the literature. In the present study, instead certain volumes of interest (VOIs) obtained by CT scan and the corresponding HU to the respective VOIs were compared with the bone mineral density of the corresponding areas measured by DEXA. The aim of the study was to investigate whether this procedure gives more accurate information about bone density of the bones as three-dimensional objects of the respective patient. Correlation between measured HU in the respective VOI and BMD measured with DEXA in the corresponding ROI showed a very good correlation of 0.93. Linear regression with R2 = 0.85 ( p = 0.0262) was calculated. Except for VOI5, similar distribution of values and significant differences ( p < 0.0001-0.0087) between ROIs/VOIs were detected. Determining HU for assessing bone mineral density in a certain volume provides more accurate results than those previously reported from two-dimensional (2D) CT measurements. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:2667-2672, 2017. [ABSTRACT FROM AUTHOR]

Purpose: The focus of this work is the development of a novel blade collimation system enabling volume of interest (VOI) CBCT with tube current modulation using the kV image guidance source on a linear accelerator. Advantages of the system are assessed, particularly with regard to reduction and localization of dose and improvement of image quality. Methods: A four blade dynamic kV collimator was developed to track a VOI during a CBCT acquisition. The current prototype is capable of tracking an arbitrary volume defined by the treatment planner for subsequent CBCT guidance. During gantry rotation, the collimator tracks the VOI with adjustment of position and dimension. CBCTimage quality was investigated as a function of collimator dimension, while maintaining the same dose to the VOI, for a 22.2 cm diameter cylindrical water phantom with a 9 mm diameter bone insert centered on isocenter. Dose distributions were modeled using a dynamic BEAMnrc library and DOSXYZnrc. The resulting VOI dose distributions were compared to full-field CBCT distributions to quantify dose reduction and localization to the target volume. A novel method of optimizing x-ray tube current during CBCT acquisition was developed and assessed with regard to contrast-to-noise ratio(CNR) and imagingdose. Results: Measurements show that the VOI CBCT method using the dynamic blade system yields an increase in contrast-to-noise ratio by a factor of approximately 2.2. Depending upon the anatomical site, dose was reduced to 15%-80% of the full-field CBCT value along the central axis plane and down to less than 1% out of plane. The use of tube current modulation allowed for specification of a desired SNR within projection data. For approximately the same dose to the VOI, CNR was further increased by a factor of 1.2 for modulated VOI CBCT, giving a combined improvement of 2.6 compared to full-field CBCT. Conclusions: The present dynamic blade system provides significant improvements in CNR for the same imagingdose and localization of imagingdose to a predefined volume of interest. The approach is compatible with tube current modulation, allowing optimization of the imaging protocol. [ABSTRACT FROM AUTHOR]

Micro-computed tomographic analyses of trabecular bone architecture have been used to clarify the link between positional behavior and skeletal anatomy in primates. However, there are methodological decisions associated with quantifying and comparing trabecular anatomy across taxa that vary greatly in body size and morphology that can affect characterizations of trabecular architecture, such as choice of the volume of interest (VOI) size and location. The potential effects of these decisions may be amplified in small, irregular-shaped bones of the hands and feet that have more complex external morphology and more heterogeneous trabecular structure compared to, for example, the spherical epiphysis of the femoral head. In this study we investigate the effects of changes in VOI size and location on standard trabecular parameters in two bones of the hand, the capitate and third metacarpal, in a diverse sample of nonhuman primates that vary greatly in morphology, body mass and positional behavior. Results demonstrate that changes in VOI location and, to a lesser extent, changes in VOI size had a dramatic affect on many trabecular parameters, especially trabecular connectivity and structure (rods vs. plates), degree of anisotropy, and the primary orientation of the trabeculae. Although previous research has shown that some trabecular parameters are susceptible to slight variations in methodology (e.g. VOI location, scan resolution), this study provides a quantification of these effects in hand bones of a diverse sample of primates. An a priori understanding of the inherent biases created by the choice of VOI size and particularly location is critical to robust trabecular analysis and functional interpretation, especially in small bones with complex arthroses. [ABSTRACT FROM AUTHOR]

This work is to demonstrate that high quality cone beam CT images can be generated for a volume of interest (VOI) and to investigate the exposure reduction effect, dose saving, and scatter reduction with the VOI scanning technique. The VOI scanning technique involves inserting a filtering mask between the x-ray source and the breast during image acquisition. The mask has an opening to allow full x-ray exposure to be delivered to a preselected VOI and a lower, filtered exposure to the region outside the VOI. To investigate the effects of increased noise due to reduced exposure outside the VOI on the reconstructed VOI image, we directly extracted the projection data inside the VOI from the full-field projection data and added additional data to the projection outside the VOI to simulate the relative noise increase due to reduced exposure. The nonuniform reference images were simulated in an identical manner to normalize the projection images and measure the x-ray attenuation factor for the object. Regular Feldkamp–Davis–Kress filtered backprojection algorithm was used to reconstruct the 3D images. The noise level inside the VOI was evaluated and compared with that of the full-field higher exposure image. Calcifications phantom and low contrast phantom were imaged. Dose reduction was investigated by estimating the dose distribution in a cylindrical water phantom using Monte Carlo simulation based Geant4 package. Scatter reduction at the detector input was also studied. Our results show that with the exposure level reduced by the VOI mask, the dose levels were significantly reduced both inside and outside the VOI without compromising the accuracy of image reconstruction, allowing for the VOI to be imaged with more clarity and helping to reduce the breast dose. The contrast-to-noise ratio inside the VOI was improved. The VOI images were not adversely affected by noisier projection data outside the VOI. Scatter intensities at the detector input were also shown to decrease significantly both inside and outside the VOI in the projection images, indicating potential improvement of image quality inside the VOI and contribution to dose reduction both inside and outside the VOI. [ABSTRACT FROM AUTHOR]

In vivo functional neuroimaging technology enables the evaluation of behavior-related changes in measured brain activity within specific cortical regions of interest (ROIs). When sufficient neurophysiologic evidence exists to restrict attention to a defined cortical region, an ROI analysis can provide powerful insights regarding neural representations of cognition, emotions, behaviors, and the neuropathology of psychiatric disorders. Given the complexity and abundance of data from neuroimaging experiments, anatomically focused research questions allow statisticians to explore models that more accurately reflect neurophysiologic characteristics of the data than global activation studies. Neural processing characteristics of particular interest in this article are spatial correlations stemming from the interplay between spatially distinct brain locations and temporal correlations between serial measures of brain activity. Despite the simplified data structure of ROI studies, challenges remain in modeling spatial correlations due to, for example, the fact that the correlations do not necessarily decrease as a function of increasing separation between the measurement locations. This article presents a spatiotemporal model that incorporates a functionally defined distance metric into a parametric structure for spatial correlations and includes temporal correlations between repeated scans. We demonstrate the use of the spatiotemporal model using experimental data from a study of the effects of ethanol administration on brain activity in the cerebellum, which largely controls balance and posture. We further illustrate our model using data simulated from a study evaluating neural processing alterations in the right prefrontal cortex associated with mental arithmetic. [ABSTRACT FROM AUTHOR]

We compared the registration accuracy for corresponding anatomical landmarks in two MR images after fusing the complete volume (CV) and a defined volume of interest (VOI) of both MRI data sets. We carried out contrast-enhanced T1-weighted gradient-echo and T2-weighted fast spin-echo MRI (matrix 256×256) in 39 cases. The CV and a defined VOI data set were each fused using prototype software. We measured and analysed the distance between 25 anatomical landmarks in predefined areas identified at levels L1–L5 corresponding to defined axial sections. Fusion technique, landmark areas and level of fusion were further processed using a feed-forward neural network to calculate the difference which can be expected based on the measurements. We identified 975 landmarks for both T1- and T2-weighted images and found a significant difference in registration accuracy (P<0.01) for all landmarks between CV (1.6±1.2 mm) and VOI (0.7±1.0 mm). From cranial (L1) to caudal (L5), mean deviations were: L1 CV 1.5 mm, VOI 0.5 mm; L2 CV 1.8 mm, VOI 0.4 mm; L3 CV 1.7 mm, VOI 0.4 mm; L4 CV 1.6 mm, VOI 0.6 mm; and L5 CV 1.6 mm, VOI 1.6 mm. Neural network analysis predicted a higher accuracy for VOI (0.05–0.15 mm) than for CV fusion (0.9–1.6 mm). Deviations due to magnetic susceptibility changes between air and tissue seen on gradient-echo images can decrease fusion accuracy. Our VOI fusion technique improves image fusion accuracy to <0.5 mm by excluding areas with marked susceptibility changes. [ABSTRACT FROM AUTHOR]

This paper presents a new method for extracting bronchus regions from 3D chest X-ray CT images based on structural features of the bronchus. This method enhances bronchial walls by applying a sharpening operation and segments each bronchial branch by recognizing the tree structure starting from the trachea. During the extraction process, the volumes of interests (VOI) which contain the bronchial branch currently being processed are defined. Region growing is performed only inside a VOI so that a bronchial branch is extracted by a suitable threshold value. The final bronchus region is obtained by unifying the extracted branches. The tree structure of the bronchus is also extracted simultaneously. The proposed method was applied to three cases of 3D chest X-ray CT images. The experimental results showed that the method significantly improved extraction accuracy. About 82% of the branches is extracted for the 4th-order bronchi, 49% for 5th-order bronchi, and 20% for 6th-order bronchi, compared to 45%, 16%, and 3% by the previous method using the region-growing method with a constant threshold value. [Copyright &y& Elsevier]

Specific region-based analysis for the quantification of brain imaging is very time-consuming work and subject to errors in both accuracy and reproducibility. In this study, we assessed a two-step template-based method for defining volumes of interest (VOIs). The first step was the spatial transformation of the VOI template from a model MRI to an individual MRI with SPM99. The second step was to refine the transformed VOI to the individual gray matter of MRI using the intensity characteristics of this image with our developed software running on a PC type of computer. The reliability of the values of the final refined VOIs was investigated by comparing them to those of manually drawn VOIs. The template-based method was found to be both accurate and robust and can be used as a reliable alternative for the manual determination of VOIs. [Copyright &y& Elsevier]

• Influence of µCT-scanning resolution on results of mechanical FEM-simulations. • Influence of virtual sample volume on results of FEM-Simulations. • Determination of representative Volume-of-interest for FEM-Simulations. Complex cellular ceramic structures are commonly fabricated via replica technique, gel-casting, or freeze-drying. These structures exhibit a manufacturing-related heterogeneity in their microstructure associated with a large scattering range of their physical properties. This further complicates the determination of the representative volume-of-interest (VOI) for the corresponding characterization method. Periodic cellular ceramics can be systematically investigated by µCT analysis to determine the influence of the scan resolution on the results of the mechanical FEM simulation under the same boundary conditions (load, displacement). In this work, a complex 3D printed Al 2 O 3 structure with 3 × 3 × 3 arranged cubic unit cells is scanned with three different µCT resolutions (6.87 µm, 13.56 µm and 27.11 µm). From the scans, FE models and sub-volumes are created with a gradation by a factor of 2 down to 1/8 of the initial volume to determine the representative VOI. It was demonstrated that a good agreement with the experimental data can only be achieved with the highest scanning resolution, but here a reduction of the VOI by a factor of four is possible to obtain identical results despite slight production-related deviations. [ABSTRACT FROM AUTHOR]