Comparison of One-Dimensional and Volumetric Computed Tomography Measurements of Injected-Water Phantoms
Ontology highlight
ABSTRACT:
SUBMITTER: Levine Z
PROVIDER: S-EPMC7339618 | biostudies-literature |
REPOSITORIES: biostudies-literature
Similar Datasets
Project description:In modern clinical decision-support algorithms, heterogeneity in image characteristics due to variations in imaging systems and protocols hinders the development of reproducible quantitative measures including for feature extraction pipelines. With the help of a reader study, we investigate the ability to provide consistent ground-truth targets by using patient-specific 3D-printed lung phantoms. PixelPrint was developed for 3D-printing lifelike computed tomography (CT) lung phantoms by directly translating clinical images into printer instructions that control density on a voxel-by-voxel basis. Data sets of three COVID-19 patients served as input for 3D-printing lung phantoms. Five radiologists rated patient and phantom images for imaging characteristics and diagnostic confidence in a blinded reader study. Effect sizes of evaluating phantom as opposed to patient images were assessed using linear mixed models. Finally, PixelPrint's production reproducibility was evaluated. Images of patients and phantoms had little variation in the estimated mean (0.03-0.29, using a 1-5 scale). When comparing phantom images to patient images, effect size analysis revealed that the difference was within one-third of the inter- and intrareader variabilities. High correspondence between the four phantoms created using the same patient images was demonstrated by PixelPrint's production repeatability tests, with greater similarity scores between high-dose acquisitions of the phantoms than between clinical-dose acquisitions of a single phantom. We demonstrated PixelPrint's ability to produce lifelike CT lung phantoms reliably. These phantoms have the potential to provide ground-truth targets for validating the generalizability of inference-based decision-support algorithms between different health centers and imaging protocols and for optimizing examination protocols with realistic patient-based phantoms. Classification: CT lung phantoms, reader study.
| S-EPMC9992761 | biostudies-literature
Project description:SignificanceWhen developing a new quantitative optoacoustic computed tomography (OAT) system for diagnostic imaging of breast cancer, objective assessments of various system designs through human trials are infeasible due to cost and ethical concerns. In prototype stages, however, different system designs can be cost-efficiently assessed via virtual imaging trials (VITs) employing ensembles of digital breast phantoms, i.e., numerical breast phantoms (NBPs), that convey clinically relevant variability in anatomy and optoacoustic tissue properties.AimThe aim is to develop a framework for generating ensembles of realistic three-dimensional (3D) anatomical, functional, optical, and acoustic NBPs and numerical lesion phantoms (NLPs) for use in VITs of OAT applications in the diagnostic imaging of breast cancer.ApproachThe generation of the anatomical NBPs was accomplished by extending existing NBPs developed by the U.S. Food and Drug Administration. As these were designed for use in mammography applications, substantial modifications were made to improve blood vasculature modeling for use in OAT. The NLPs were modeled to include viable tumor cells only or a combination of viable tumor cells, necrotic core, and peripheral angiogenesis region. Realistic optoacoustic tissue properties were stochastically assigned in the NBPs and NLPs.ResultsTo advance optoacoustic and optical imaging research, 84 datasets have been released; these consist of anatomical, functional, optical, and acoustic NBPs and the corresponding simulated multi-wavelength optical fluence, initial pressure, and OAT measurements. The generated NBPs were compared with clinical data with respect to the volume of breast blood vessels and spatially averaged effective optical attenuation. The usefulness of the proposed framework was demonstrated through a case study to investigate the impact of acoustic heterogeneity on OAT images of the breast.ConclusionsThe proposed framework will enhance the authenticity of virtual OAT studies and can be widely employed for the investigation and development of advanced image reconstruction and machine learning-based methods, as well as the objective evaluation and optimization of the OAT system designs.
| S-EPMC10281048 | biostudies-literature
Project description:ObjectivesTo evaluate and compare surface doses of a cone beam computed tomography (CBCT) and a multidetector computed tomography (MDCT) device in pediatric ankle and wrist phantoms.MethodsThermoluminescent dosimeters (TLD) were used to measure and compare surface doses between CBCT and MDCT in a left ankle and a right wrist pediatric phantom. In both modalities adapted pediatric dose protocols were utilized to achieve realistic imaging conditions. All measurements were repeated three times to prove test-retest reliability. Additionally, objective and subjective image quality parameters were assessed.ResultsAverage surface doses were 3.8 ±2.1 mGy for the ankle, and 2.2 ±1.3 mGy for the wrist in CBCT. The corresponding surface doses in optimized MDCT were 4.5 ±1.3 mGy for the ankle, and 3.4 ±0.7 mGy for the wrist. Overall, mean surface dose was significantly lower in CBCT (3.0 ±1.9 mGy vs. 3.9 ±1.2 mGy, p<0.001). Subjectively rated general image quality was not significantly different between the study protocols (p = 0.421), whereas objectively measured image quality parameters were in favor of CBCT (p<0.001).ConclusionsAdapted extremity CBCT imaging protocols have the potential to fall below optimized pediatric ankle and wrist MDCT doses at comparable image qualities. These possible dose savings warrant further development and research in pediatric extremity CBCT applications.
| S-EPMC5453596 | biostudies-literature
Project description:BackgroundProstatic diseases are common and mostly associated with enlargement of the accessory gland. Thus, determining the prostate size has become a main criterion for evaluating prostate health status. Computed tomography (CT) is recommended as a beneficial tool for evaluating prostate size, morphology and surrounding tissues. The purpose of this study was to establish an accurate procedure for volume estimation and afterwards evaluate the prostate volume in CT. Data of 95 dogs were analysed (58 male intact, 37 male neutered) using the slice addition technique with the Amira program. Accuracy of volumetric measurements by CT was validated by comparing them with those of phantoms of known volume. Patients were grouped according to age (< 4 yrs., 4-8 yrs., > 8 yrs) and prostate morphology in CT (H = homogeneous, I = inhomogeneous, C = cystic). The length of the sixth lumbar vertebra was measured to relate prostate volume to body size. This ratio was generated to compare prostate volume between the groups, irrespective of body size (ratio volume = Rv).ResultsA high correlation between the CT-derived and phantom volume was found. Overall, the mean prostate volume was 58.6 cm3. The mean ratio volume was 1.3 in intact male dogs, this being significantly higher than in neutered dogs (0.7). The lowest ratio volume values were found in group H for intact (Rv = 0.9) and neutered dogs (Rv = 0.6), followed by group I (intact: Rv = 1.1; neutered: Rv = 0.7) and C (intact: Rv = 1.4; neutered: Rv = 0.8). The length of the sixth lumbar vertebra was well correlated with the prostate volume (intact: r = 0.63, p < 0.001; neutered: r = 0.48, p = 0.003), while age exhibited a correlation only in intact dogs (r = 0.52, p < 0.001).ConclusionThe present study is pioneering in applying a slice addition technique to volumetric measurements of the prostate gland in CT, resulting in a highly precise method. Volumetric measurements of the canine prostate gland in CT images provide information about the prostate structure, castration status, age and body size of the patients. Therefore, prostate volume is a relevant parameter for evaluating prostate health status.
| S-EPMC6360749 | biostudies-literature
Project description:Four-dimensional computed tomography (4DCT), or dynamic CT, is an emerging modality with a wealth of orthopedic applications for both clinical practice and research. This technology creates CT volumes of a moving structure at multiple time points to depict real-time motion. Recent advances in acquisition technology and reduction in radiation dosage have allowed for increased adoption of the modality and have made imaging of joint motion feasible and safe. Musculoskeletal 4DCT has been used primarily to investigate wrist motion; however, the utility of 4DCT has been shown in other areas, including the shoulder, elbow, hip, knee and ankle. Imaging these joints through a full range of motion provides new insight into dynamic phenomena such as instability, impingement and joint kinematics. Although 4DCT has not yet been widely adopted in orthopedic practice and research, future use has the potential to enable a deeper understanding of musculoskeletal conditions and to improve patient care.
| S-EPMC9200445 | biostudies-literature
Project description:Background and purposeFour-dimensional (4D) computed tomography (CT) is widely used in radiotherapy (RT) planning and remains the current standard for motion evaluation. We assess a 4D magnetic resonance imaging (MRI) sequence in terms of motion and image quality in a phantom, healthy volunteers and patients undergoing RT.Materials and methodsThe 4D-MRI sequence is a prototype T1-weighted 3D gradient echo with radial acquisition with self-gating. The accuracy of the 4D-MRI respiratory sorting based method was assessed using a MRI-CT compatible respiratory simulation phantom. In volunteers, abdominal viscera were evaluated for artefact, noise, structure delineation and overall image quality using a previously published four-point scoring system. In patients undergoing abdominal RT, the tumour (or a surrogate) was utilized to assess the range of motion on both 4D-CT and 4D-MRI. Furthermore, imaging quality was evaluated for both 4D-CT and 4D-MRI.ResultsIn phantom studies 4D-MRI demonstrated amplitude of motion error of less than 0.2 mm for five, seven and ten bins. 4D-MRI provided excellent image quality for liver, kidney and pancreas. In patients, the median amplitude of motion seen on 4D-CT and 4D-MRI was 11.2 mm (range 2.8-20.3 mm) and 10.1 mm (range 0.7-20.7 mm) respectively. The median difference in amplitude between 4D-CT and 4D-MRI was -0.6 mm (range -3.4-5.2 mm). 4D-MRI demonstrated superior edge detection (median score 3 versus 1) and overall image quality (median score 2 versus 1) compared to 4D-CT.ConclusionsThe prototype 4D-MRI sequence demonstrated promising results and may be used in abdominal targeting, motion gating, and towards implementing MRI-based adaptive RT.
| S-EPMC7807635 | biostudies-literature
Project description:Photoacoustic tomography (PAT) has been widely used to image optically absorptive objects in both human and animal tissues. For the first time, we present imaging of water with laser-based PAT. We photoacoustically measure the absorption spectra of water-ethanol mixtures at various water concentrations, and then image water-ethanol and pure-water inclusions in gel and a water inclusion in fat tissue. The significant difference in photoacoustic signals between water and fat tissue indicates that the laser-based PAT has the potential to detect water content in tissue.
| S-EPMC2904025 | biostudies-other
Project description:The aim of this study was to compare the performance of 2- (2D) and 3-dimensional (3D) quantitative computed tomography (CT) methods for classifying lung nodules as lung cancer, metastases, or benign.Using semiautomated software and computerized analysis, we analyzed more than 50 quantitative CT features of 96 solid nodules in 94 patients, in 2D from a single slice and in 3D from the entire nodule volume. Multivariable logistic regression was used to classify nodule types. Model performance was assessed by the area under the receiver operating characteristic curve (AUC) using leave-one-out cross-validation.The AUC for distinguishing 53 primary lung cancers from 18 benign nodules and 25 metastases ranged from 0.79 to 0.83 and was not significantly different for 2D and 3D analyses (P = 0.29-0.78). Models distinguishing metastases from benign nodules were statistically significant only by 3D analysis (AUC = 0.84).Three-dimensional CT methods did not improve discrimination of lung cancer, but may help distinguish benign nodules from metastases.
| S-EPMC4949123 | biostudies-literature
Project description:ObjectivesWe compared the computed tomographic (CT) volumetric analysis and anatomical segment counting (ASC) for predicting postoperative forced expiratory volume in 1 s (FEV1) and diffusing capacity for carbon monoxide (DLCO) in patients who had segmentectomy for early-stage lung cancer.MethodsA total of 175 patients who had segmentectomy for lung cancer and had postoperative pulmonary function test were included. CT volumetric analysis was performed by software, which could measure total lung and target segment volume from CT images. ASC and CT volumetric analysis were used to determine predicted postoperative (PPO) values and the concordance and difference of these values were assessed. The relationship between PPO values and actual postoperative values was also investigated.ResultsThe PPO-FEV1 and PPO-DLCO showed high concordance between 2 methods (concordance correlation coefficient = 0.96 for PPO-FEV1 and 0.95 for PPO-DLCO). There was no significant difference between PPO values as determined by 2 methods (P = 0.53 for PPO-FEV1, P = 0.25 for PPO-DLCO) and actual postoperative values [P = 0.77 (ASC versus actual) and P = 0.20 (CT versus actual) for FEV1; P = 0.41 (ASC versus actual) and P = 0.80 (CT versus actual) for DLCO]. We subdivided the patients according to poor pulmonary function test, the number of resected segments and the location of the resected lobe. All subgroup analyses revealed no significant difference between PPO values and actual postoperative values.ConclusionsBoth CT volumetric analysis and ASC showed high predictability for actual postoperative FEV1 and DLCO in segmentectomy.
| S-EPMC9338704 | biostudies-literature
Project description:PurposeTo examine the use of multiple fast-helical free breathing computed tomography (FHFBCT) scans for ventilation measurement.MethodsTen patients were scanned 25 times in alternating directions using a FHFBCT protocol. Simultaneously, an abdominal pneumatic bellows was used as a real-time breathing surrogate. Regions-of-interest (ROIs) were selected from the upper right lungs of each patient for analysis. The ROIs were first registered using a published registration technique (pTV). A subsequent follow-up registration employed an objective function with two terms, a ventilation-adjusted Hounsfield Unit difference and a conservation-of-mass term labeled ΔΓ that denoted the difference between the deformation Jacobian and the tissue density ratio. The ventilations were calculated voxel-by-voxel as the slope of a first-order fit of the Jacobian as a function of the breathing amplitude.ResultsThe ventilations of the 10 patients showed different patterns and magnitudes. The average ventilation calculated from the deformation vector fields (DVFs) of the pTV and secondary registration was nearly identical, but the standard deviation of the voxel-to-voxel differences was approximately 0.1. The mean of the 90th percentile values of ΔΓ was reduced from 0.153 to 0.079 between the pTV and secondary registration, implying first that the secondary registration improved the conservation-of-mass criterion by almost 50% and that on average the correspondence between the Jacobian and density ratios as demonstrated by ΔΓ was less than 0.1. This improvement occurred in spite of the average of the 90th percentile changes in the DVF magnitudes being only 0.58 mm.ConclusionsThis work introduces the use of multiple free-breathing CT scans for free-breathing ventilation measurements. The approach has some benefits over the traditional use of 4-dimensional CT (4DCT) or breath-hold scans. The benefit over 4DCT is that FHFBCT does not have sorting artifacts. The benefits over breath-hold scans include the relatively small motion induced by quiet respiration versus deep-inspiration breath hold and the potential for characterizing dynamic breathing processes that disappear during breath hold.
| S-EPMC8568635 | biostudies-literature