scholarly journals How CT reconstruction parameters effect measurement error of pulmonary nodules volume

2020 ◽  
Vol 12 (3) ◽  
pp. 73-77
Author(s):  
Zaur A. Alderov ◽  
Evgeny V. Rozengauz ◽  
Denis Nesterov
Keyword(s):  
Systematic Error ◽  
Linear Regression Analysis ◽  
Ct Scanning ◽  
Lesion Size ◽  
Slice Thickness ◽  
Ct Reconstruction ◽  
Size Estimation ◽  
Stochastic Errors ◽  
Volumetric Errors ◽  
Reconstruction Kernel

One of the the widely used way to follow up oncological disease is estimation of lesion size differences. Volumetry is one of the most accurate approaches of lesion size estimation. However, being highly sensitive, volumetric errors can reach 60%, which significantly limits the applicability of the method. Purpose was to estimate the effect of reconstruction parameters on volumetry error. Materials and methods. 32 patients with pulmonary metastases underwent a CT scanning with 326 foci detected. 326 pulmonary were segmented. Volumetry error was estimated for every lesion with each combination of slice thickness and reconstruction kernel. The effect was measured with linear regression analysis Results. Systematic and stochastic errors are impacted by slice thickness, reconstruction kernel, lesion position and its diameter. FC07 kernel and larger slice thickness is associated with high systematic error. Both systematic and stochastic errors decrease with lesion enlargment. intrapulmonary lesions have the lowest error regardless the reconstruction parameters. Lineal regression model was created to prognose error rate. Model standart error was 6.7%. There was corelation between model remnants deviation and slice thickness, reconstruction kernel, lesion position and its diameter. Conclusion. The systematic error depends on the focal diameter, slice thickness and reconstruction kernel. It can be estimated using the proposed model with a 6% error. Stochastic error mainly depends on lesion size.

scholarly journals Evaluating a calcium-aware kernel for CT CAC scoring with varying surrounding materials and heart rates: a dynamic phantom study

2021 ◽  
Author(s):  
Niels R. van der Werf ◽  
Ronald Booij ◽  
Bernhard Schmidt ◽  
Thomas G. Flohr ◽  
Tim Leiner ◽  
...  
Keyword(s):  
Coronary Artery ◽  
Soft Tissue ◽  
Patient Specific ◽  
Reconstruction Technique ◽  
Ct Reconstruction ◽  
Raw Data ◽  
Heart Rates ◽  
Tissue Equivalent ◽  
Tin Filtration ◽  
Reconstruction Kernel

Abstract Objectives The purpose of this study was twofold. First, the influence of a novel calcium-aware (Ca-aware) computed tomography (CT) reconstruction technique on coronary artery calcium (CAC) scores surrounded by a variety of tissues was assessed. Second, the performance of the Ca-aware reconstruction technique on moving CAC was evaluated with a dynamic phantom. Methods An artificial coronary artery, containing two CAC of equal size and different densities (196 ± 3, 380 ± 2 mg hydroxyapatite cm−3), was moved in the center compartment of an anthropomorphic thorax phantom at different heart rates. The center compartment was filled with mixtures, which resembled fat, water, and soft tissue equivalent CT numbers. Raw data was acquired with a routine clinical CAC protocol, at 120 peak kilovolt (kVp). Subsequently, reduced tube voltage (100 kVp) and tin-filtration (150Sn kVp) acquisitions were performed. Raw data was reconstructed with a standard and a novel Ca-aware reconstruction technique. Agatston scores of all reconstructions were compared with the reference (120 kVp) and standard reconstruction technique, with relevant deviations defined as > 10%. Results For all heart rates, Agatston scores for CAC submerged in fat were comparable to the reference, for the reduced-kVp acquisition with Ca-aware reconstruction kernel. For water and soft tissue, medium-density Agatston scores were again comparable to the reference for all heart rates. Low-density Agatston scores showed relevant deviations, up to 15% and 23% for water and soft tissue, respectively. Conclusion CT CAC scoring with varying surrounding materials and heart rates is feasible at patient-specific tube voltages with the novel Ca-aware reconstruction technique. Key Points • A dedicated calcium-aware reconstruction kernel results in similar Agatston scores for CAC surrounded by fatty materials regardless of CAC density and heart rate. • Application of a dedicated calcium-aware reconstruction kernel allows for radiation dose reduction. • Mass scores determined with CT underestimated physical mass.

Contrast-enhanced spectral mammography in patients with MRI contraindications

2017 ◽  
Vol 59 (7) ◽  
pp. 798-805 ◽  
Author(s):  
Vivien Richter ◽  
Valerie Hatterman ◽  
Heike Preibsch ◽  
Sonja D Bahrs ◽  
Markus Hahn ◽  
...  
Keyword(s):  
Problem Solving ◽  
Diagnostic Accuracy ◽  
Breast Imaging ◽  
Diagnostic Yield ◽  
Therapy Response ◽  
Lesion Size ◽  
Size Estimation ◽  
Imaging Data ◽  
Technical Problems ◽  
Contrast Enhanced

Background Contrast-enhanced spectral mammography (CESM) is a novel breast imaging technique providing comparable diagnostic accuracy to breast magnetic resonance imaging (MRI). Purpose To show that CESM in patients with MRI contraindications is feasible, accurate, and useful as a problem-solving tool, and to highlight its limitations. Material and Methods A total of 118 patients with MRI contraindications were examined by CESM. Histology was obtained in 94 lesions and used as gold standard for diagnostic accuracy calculations. Imaging data were reviewed retrospectively for feasibility, accuracy, and technical problems. The diagnostic yield of CESM as a problem-solving tool and for therapy response evaluation was reviewed separately. Results CESM was more accurate than mammography (MG) for lesion categorization (r = 0.731, P < 0.0001 vs. r = 0.279, P = 0.006) and for lesion size estimation (r = 0.738 vs. r = 0.689, P < 0.0001). Negative predictive value of CESM was significantly higher than of MG (85.71% vs. 30.77%, P < 0.0001). When used for problem-solving, CESM changed patient management in 2/8 (25%) cases. Superposition artifacts and timing problems affected diagnostic utility in 3/118 (2.5%) patients. Conclusion CESM is a feasible and accurate alternative for patients with MRI contraindications, but it is necessary to be aware of the method’s technical limitations.

Pseudoenhancement of Renal Cysts: Influence of Lesion Size, Lesion Location, Slice Thickness, and Number of MDCT Detectors

2012 ◽  
Vol 198 (1) ◽  
pp. 133-137 ◽  
Author(s):  
Rafel Tappouni ◽  
Jennifer Kissane ◽  
Nabeel Sarwani ◽  
Erik B. Lehman
Keyword(s):  
Renal Cysts ◽  
Lesion Size ◽  
Slice Thickness ◽  
Lesion Location

Three Dimensional CT Reconstruction for the Evaluation and Surgical Planning of Facial Fractures

1986 ◽  
Vol 95 (1) ◽  
pp. 10-15 ◽  
Author(s):  
Peter J. Koltai ◽  
Gary W. Wood
Keyword(s):  
Surgical Planning ◽  
Three Dimensional ◽  
Ct Scanning ◽  
Data Systems ◽  
Ct Reconstruction ◽  
Facial Fractures ◽  
Facial Skeleton ◽  
The Face ◽  
Spatial Imagination ◽  
The Relationship

Despite advances in radiology—including CT scanning—the three-dimensional (3D) nature of facial fractures must still be inferred by the spatial imagination of the physician. A computer system (Insight Phoenix Data Systems, Inc., Albany, N.Y.) uses CT studies as substrate for 3D reconstructions. We have used the insight computer for the evaluation and surgical planning of facial fractures of 16 patients with complex injuries. We present five illustrative cases, directly photographed from the computer monitor. Images can also be manipulated in real time by rotating or planar sectioning (functions best appreciated on video). The ability to cybernetically extract the facial skeleton from living subjects provides precise anatomic data previously unobtainable. The images are valuable for an accurate assessment of the relationship between the injured and uninjured sections of the face. We conclude that 3D reconstruction is an important advance in the treatment of facial fractures.

scholarly journals Frameless Stereotaxy for Pre-treatment Planning and Post-treatment Evaluation of Radiosurgery

1994 ◽  
Vol 21 (4) ◽  
pp. 319-324 ◽  
Author(s):  
M.L. Schwartz ◽  
R. Ramami ◽  
P.F. O’Brien ◽  
C.S. Young ◽  
P. Davey ◽  
...  
Keyword(s):  
Ct Scan ◽  
Cross Sections ◽  
Ct Scanning ◽  
Frameless Stereotaxy ◽  
Slice Thickness ◽  
Fiducial Markers ◽  
The Real ◽  
Observer Error ◽  
Angiographic Ct ◽  
Bony Landmarks

Abstract:In our centre, 111 patients have been treated with linear accelerator stereotactic radiosurgery. Angiographic, CT and MRI images are generated and the target coordinates calculated in 3 dimensions. For CT scanning, cross sections of perpendicular and oblique fiducial markers are seen. For follow-up CT scans done without the frame, a virtual frame is generated by means of a computer program that places fiducial markers on each CT scan cut, as if the patient had been wearing the OBT frame and the scan produced with the gantry parallel to the base of the frame. The position of the oblique marker may be calculated by knowing the thickness and position of each CT cut. Various natural fiducial markers (bony landmarks) are identified by coordinates in the scan with the patient wearing the real frame and in the scan with the virtual frame applied. A transformation matrix is utilized to establish the equivalence between the original CT scan with the real frame applied and subsequent scans without the real frame but with the virtual frame applied. In effect, the virtual frame is re-applied in exactly the same position as the real frame. Lesion measurements may then be duplicated and growth or regression accurately established. The uncertainty in this system of re-application resides in possible patient movement, CT scan slice thickness and inter-observer error in the identification of natural fiducial markers.

scholarly journals An Approximate Cone Beam Reconstruction Algorithm for Gantry-Tilted CT Using Tangential Filtering

2006 ◽  
Vol 2006 ◽  
pp. 1-8
Author(s):  
Ming Yan ◽  
Cishen Zhang ◽  
Hongzhu Liang
Keyword(s):  
Image Reconstruction ◽  
Cone Angle ◽  
Three Dimensional ◽  
Ct Scanning ◽  
Reconstruction Algorithm ◽  
Tangential Direction ◽  
Approximate Algorithm ◽  
Projection Data ◽  
Ct Reconstruction ◽  
Fdk Algorithm

FDK algorithm is a well-known 3D (three-dimensional) approximate algorithm for CT (computed tomography) image reconstruction and is also known to suffer from considerable artifacts when the scanning cone angle is large. Recently, it has been improved by performing the ramp filtering along the tangential direction of the X-ray source helix for dealing with the large cone angle problem. In this paper, we present an FDK-type approximate reconstruction algorithm for gantry-tilted CT imaging. The proposed method improves the image reconstruction by filtering the projection data along a proper direction which is determined by CT parameters and gantry-tilted angle. As a result, the proposed algorithm for gantry-tilted CT reconstruction can provide more scanning flexibilities in clinical CT scanning and is efficient in computation. The performance of the proposed algorithm is evaluated with turbell clock phantom and thorax phantom and compared with FDK algorithm and a popular 2D (two-dimensional) approximate algorithm. The results show that the proposed algorithm can achieve better image quality for gantry-tilted CT image reconstruction.

scholarly journals Automated 3D MRI Allows for Accurate Evaluation of Glenoid Bone Loss as Compared to 3D CT

2018 ◽  
Vol 6 (7_suppl4) ◽  
pp. 2325967118S0008
Author(s):  
Drew A. Lansdown ◽  
Robert Dawe ◽  
Gregory L. Cvetanovich ◽  
Nikhil N. Verma ◽  
Brian J. Cole ◽  
...  
Keyword(s):  
Bone Loss ◽  
3D Reconstruction ◽  
Ct Scan ◽  
Glenoid Bone Loss ◽  
Ct Scans ◽  
Reconstruction Method ◽  
Slice Thickness ◽  
3D Ct ◽  
Ct Reconstruction ◽  
3D Mri

Objectives: Glenoid bone loss is frequently present in the setting of recurrent shoulder instability. The magnitude of bone loss is an important determinant of the optimal surgical treatment. The current gold-standard for measurement of glenoid bone loss is three-dimensional (3D) reconstruction of a computed tomography (CT) scan. CT scans, however, carry an inherent risk of radiation and increased cost for a second modality. Magnetic resonance imaging (MRI) offers excellent soft tissue contrast and may allow resolution of bony structures to generate 3D reconstructions without a risk of ionizing radiation. We hypothesized that automated 3D MRI reconstruction would offer similar measurements of glenoid bone loss as recorded from a 3D CT scan in a clinical setting. Methods: A retrospective review was performed for fourteen patients who had both pre-operative MRI scan and CT scan of the shoulder. All MR scans were performed on a 1.5 T scanner (Siemens) utilizing a Dixon chemical shift separation sequence and the out-of-phase images with 0.90 mm slice thickness. Reconstructions of the glenoid were performed from axial images (Figure 1A) using an open-platform image processing system (3D Slicer; slicer.org). A single point on the glenoid was selected and a standard threshold was used to build a 3D model (Figure 1B). High-resolution CT scans underwent 3D reconstruction in Slicer based on Houndsfield Unit thresholding. Glenoid bone loss on both scans was measured with the Pico method by defining a circle of best fit using the inferior 2/3 of the glenoid and determining the percent area missing from this circle. Pearson’s correlation coefficient was utilized to determine the similarity between MR and CT based measurements. Statistical significance was defined as p<0.05. Results: The correlation between 3D MR and CT-based measurements of glenoid bone loss was excellent (r = 0.95, p<0.0001). The mean bone loss as measured by the 3D MR was 13.2 +- 7.2% and was 12.5 +- 8.6% for the 3D CT reconstruction (p=0.32). Bone loss in this cohort ranged from 3.7-25.4% on 3D MR and 1.4-26.0% on 3D CT. The root-mean-square difference between measurements was 2.7%. Conclusion: There was excellent agreement between automated 3D MR and 3D CT measurements of glenoid bone loss and minimal differences between these measurements. This reconstruction method requires minimal post-processing, no manual segmentation, and is obtained with widely-available MR sequences. This method has the potential to decrease the utilization for CT scans in determining glenoid bone loss. [Figure: see text]

Size and Effort Estimation Based on Problem Domain Measures for Object-Oriented Software

2018 ◽  
Vol 28 (02) ◽  
pp. 219-238 ◽  
Author(s):  
Tülin Erçelebi Ayyildiz ◽  
Altan Koçyiğit
Keyword(s):  
Regression Analysis ◽  
Linear Regression ◽  
Linear Regression Analysis ◽  
Object Oriented ◽  
Development Effort ◽  
Effort Estimation ◽  
Size Estimation ◽  
Problem Domain ◽  
Estimation Model ◽  
Software Projects

This paper analyzes the correlations between the problem domain measures such as the number of distinct nouns and distinct verbs in the requirements artifacts and the solution domain measures such as the number of software classes and methods in the corresponding object-oriented software. For this purpose, 14 completed software development projects of a CMMI Level-3 certified defense industry company have been analyzed. The observed strong correlation is taken as the indication of linear relationship between the measures and a size estimation model based on linear regression analysis is proposed. Prediction performance of the method is analyzed on the 14 software projects. Moreover, it has been observed that there is a high correlation between the problem domain measures and the development effort. Therefore, the linear regression analysis is also used to estimate the effort in terms of the problem domain measures. The effort estimations are also evaluated and compared with the efforts predicted using the size measured by the COSMIC Function Point (CFP) method. The results show that the proposed method provides more accurate effort estimates compared to the effort estimated by using CFP size measurement.

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