scholarly journals Impact of slice thickness, pixel size, and CT dose on the performance of automatic contouring algorithms

2021 ◽  
Author(s):  
Kai Huang ◽  
Dong Joo Rhee ◽  
Rachel Ger ◽  
Rick Layman ◽  
Jinzhong Yang ◽  
...  
Keyword(s):  
Slice Thickness ◽  
Pixel Size ◽  
Ct Dose ◽  
Automatic Contouring

scholarly journals Optimisation of T2 and T2* sequences in MRI for better quantification of iron on transfused dependent sickle cell patients

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Azza Ahmed ◽  
Amani Baldo ◽  
A. Sulieman ◽  
Hind Mirghani ◽  
Fouad A. Abolaban ◽  
...  
Keyword(s):  
Sickle Cell ◽  
Acquisition Time ◽  
Thickness Variation ◽  
Slice Thickness ◽  
Pixel Size ◽  
Significant Difference ◽  
Repetition Time

AbstractThis work aimed to investigate the effect of different shim techniques, voxel sizes, and repetition time (TR) on using theT2 and T2* sequences to determine their optimum settings to investigate the quantification of iron in transfused dependent sickle cell patients. The effect of each of these parameters was investigated on phantoms of different Gadolinium (Gd) concentrations, on 10 volunteers and 25 patients using a1 5T MRI Philips scanner. No significant difference between the three shim techniques was noticed in either T2 or T2* sequence measurements. Pixel sizes of 1 × 1 and 2 × 2 mm provided optimum results for T2 measurements. At 1 × 1 mm pixel size the T2* measurements experienced less error in measurements than the size of 2.5 × 2.5 mm used in the literature. Even though the slice thickness variation did not provide any changes in T2 measurements, the 12 mm provided optimum T2* measurements. TR variation did not yield significant changes on either T2 or T2* measurements. These results indicate that both T2 and T2* sequences can be further improved by providing more reliable measurements and reducing acquisition time.

Determination of optimum pixel size and slice thickness for tractography and ulnar nerve diffusion tensor imaging at the cubital tunnel using 3T MRI

2020 ◽  
pp. 028418512095196
Author(s):  
Sun-Young Park ◽  
Sung Hye Koh ◽  
In Jae Lee ◽  
Kwanseop Lee ◽  
Yul Lee
Keyword(s):  
Diffusion Tensor Imaging ◽  
Ulnar Nerve ◽  
Diffusion Tensor ◽  
Nerve Fibers ◽  
Cubital Tunnel ◽  
Slice Thickness ◽  
Fiber Tractography ◽  
Pixel Size ◽  
Cross Sectional ◽  
Visual Score

Background Small peripheral nerve tractography is challenging because of the trade-off among resolution, image acquisition time, and signal-to-noise ratio. Purpose To optimize pixel size and slice thickness parameters for fiber tractography and diffusion tensor imaging (DTI) of the ulnar nerve at the cubital tunnel using 3T magnetic resonance imaging (MRI). Material and Methods Fifteen healthy volunteers (mean age 30 ± 6.8 years) were recruited prospectively. Axial T2-weighted and DTI scans were acquired, covering the cubital tunnel, using different pixel sizes and slice thicknesses. Three-dimensional (3D) nerve tractography was evaluated for the median number and length of the reconstructed fiber tracts and visual score from 0 to 5. Two-dimensional (2D) cross-sectional DTI was evaluated for fractional anisotropy (FA) values throughout the length of the ulnar nerve. Results A pixel size of 1.3 mm2 revealed the highest number of reconstructed nerve fibers compared to that of 1.1 mm2 ( P = 0.048), with a good visual score. A slice thickness of 4 mm had the highest number of reconstructed nerve fibers and visual score compared with other thicknesses (all P < 0.05). In 2D cross-sectional images, the median FA values were in the range of 0.40–0.63 at the proximal, central, and distal portions of the cubital tunnel. Inter-observer agreement for all parameters was good to excellent. Conclusion For fiber tractography and DTI of the ulnar nerve at the cubital tunnel, optimal image quality was obtained using a 1.3-mm2 pixel size and 4-mm slice thickness under MR parameters of this study at 3T.

scholarly journals Fractal Analysis of Trabecular Architecture : With Special Reference to Slice Thickness and Pixel Size of the Image

2005 ◽  
Vol 61 (6) ◽  
pp. 819-825
Author(s):  
TATSUSHI TOMOMITSU ◽  
HIROAKI MIMURA ◽  
KENYA MURASE ◽  
TSUTOMU TAMADA ◽  
TERUKI SONE ◽  
...  
Keyword(s):  
Special Reference ◽  
Fractal Analysis ◽  
Slice Thickness ◽  
Trabecular Architecture ◽  
Pixel Size

scholarly journals Robustness of magnetic resonance radiomic features to pixel size resampling and interpolation in patients with cervical cancer

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Shin-Hyung Park ◽  
Hyejin Lim ◽  
Bong Kyung Bae ◽  
Myong Hun Hahm ◽  
Gun Oh Chong ◽  
...  
Keyword(s):  
Cervical Cancer ◽  
Magnetic Resonance ◽  
Intraclass Correlation ◽  
Correlation Coefficients ◽  
Texture Features ◽  
Slice Thickness ◽  
Pixel Size ◽  
First Order ◽  
Intraclass Correlation Coefficients ◽  
Standardization Process

Abstract Background Radiomics is a promising field in oncology imaging. However, the implementation of radiomics clinically has been limited because its robustness remains unclear. Previous CT and PET studies suggested that radiomic features were sensitive to variations in pixel size and slice thickness of the images. The purpose of this study was to assess robustness of magnetic resonance (MR) radiomic features to pixel size resampling and interpolation in patients with cervical cancer. Methods This retrospective study included 254 patients with a pathological diagnosis of cervical cancer stages IB to IVA who received definitive chemoradiation at our institution between January 2006 and June 2020. Pretreatment MR scans were analyzed. Each region of cervical cancer was segmented on the axial gadolinium-enhanced T1- and T2-weighted images; 107 radiomic features were extracted. MR scans were interpolated and resampled using various slice thicknesses and pixel spaces. Intraclass correlation coefficients (ICCs) were calculated between the original images and images that underwent pixel size resampling (OP), interpolation (OI), or pixel size resampling and interpolation (OP+I) as well as among processed image sets with various pixel spaces (P), various slice thicknesses (I), and both (P + I). Results After feature standardization, ≥86.0% of features showed good robustness when compared between the original and processed images (OP, OI, and OP+I) and ≥ 88.8% of features showed good robustness when processed images were compared (P, I, and P + I). Although most first-order, shape, and texture features showed good robustness, GLSZM small-area emphasis-related features and NGTDM strength were sensitive to variations in pixel size and slice thickness. Conclusion Most MR radiomic features in patients with cervical cancer were robust after pixel size resampling and interpolation following the feature standardization process. The understanding regarding the robustness of individual features after pixel size resampling and interpolation could help future radiomics research.

Stereotactic radiation treatment planning and follow-up studies involving fused multimodality imaging

2004 ◽  
Vol 101 (Supplement3) ◽  
pp. 326-333 ◽  
Author(s):  
Klaus D. Hamm ◽  
Gunnar Surber ◽  
Michael Schmücking ◽  
Reinhard E. Wurm ◽  
Rene Aschenbach ◽  
...  
Keyword(s):  
Image Fusion ◽  
Treatment Planning ◽  
Radiation Treatment ◽  
Data Sets ◽  
Slice Thickness ◽  
Radiation Treatment Planning ◽  
Content Type ◽  
Follow Up Studies ◽  
Fine Print

Object. Innovative new software solutions may enable image fusion to produce the desired data superposition for precise target definition and follow-up studies in radiosurgery/stereotactic radiotherapy in patients with intracranial lesions. The aim is to integrate the anatomical and functional information completely into the radiation treatment planning and to achieve an exact comparison for follow-up examinations. Special conditions and advantages of BrainLAB's fully automatic image fusion system are evaluated and described for this purpose. Methods. In 458 patients, the radiation treatment planning and some follow-up studies were performed using an automatic image fusion technique involving the use of different imaging modalities. Each fusion was visually checked and corrected as necessary. The computerized tomography (CT) scans for radiation treatment planning (slice thickness 1.25 mm), as well as stereotactic angiography for arteriovenous malformations, were acquired using head fixation with stereotactic arc or, in the case of stereotactic radiotherapy, with a relocatable stereotactic mask. Different magnetic resonance (MR) imaging sequences (T1, T2, and fluid-attenuated inversion-recovery images) and positron emission tomography (PET) scans were obtained without head fixation. Fusion results and the effects on radiation treatment planning and follow-up studies were analyzed. The precision level of the results of the automatic fusion depended primarily on the image quality, especially the slice thickness and the field homogeneity when using MR images, as well as on patient movement during data acquisition. Fully automated image fusion of different MR, CT, and PET studies was performed for each patient. Only in a few cases was it necessary to correct the fusion manually after visual evaluation. These corrections were minor and did not materially affect treatment planning. High-quality fusion of thin slices of a region of interest with a complete head data set could be performed easily. The target volume for radiation treatment planning could be accurately delineated using multimodal information provided by CT, MR, angiography, and PET studies. The fusion of follow-up image data sets yielded results that could be successfully compared and quantitatively evaluated. Conclusions. Depending on the quality of the originally acquired image, automated image fusion can be a very valuable tool, allowing for fast (∼ 1–2 minute) and precise fusion of all relevant data sets. Fused multimodality imaging improves the target volume definition for radiation treatment planning. High-quality follow-up image data sets should be acquired for image fusion to provide exactly comparable slices and volumetric results that will contribute to quality contol.

IMAGING CHARACTERISTIS OF MDCT IN NASOPHARYNGEAL CARCINOMA

2014 ◽  
pp. 159-167
Author(s):  
Huu Thuan Ngo ◽  
Minh Loi Hoang ◽  
Van Dinh Nguyen ◽  
Dinh Duyen Nguyen
Keyword(s):  
Nasopharyngeal Carcinoma ◽  
Lymph Nodes ◽  
Lateral Wall ◽  
Cross Sectional Study ◽  
Slice Thickness ◽  
Cross Sectional ◽  
Lymph Nodes Metastasis ◽  
Contrast Enhanced Ct ◽  
Contrast Enhanced ◽  
Key Words Nasopharyngeal Carcinoma

Objectives: Imaging characteristis of MDCT in nasopharyngeal carcinoma. Subject and methods: Cross- sectional study in 51patients with nasopharyngeal carcinoma by MDCT at Danang Cancer Hospital from January 2013 to July 2014. Results: The findings reveal that the tumor in lateral wall (66.7%), diameter > 2cm (64.7%), hypodensity (98%), contrast- enhanced CT (62.7%). Blunting of fossa of Rosenmuller (96.1%), invasion of parapharyngeal space (62.7%), destruction of pterygoid bone (19.6%), invasion of skull base (17.6%), destruction of sphenoid bone (9.8%). Lymph nodes metastasis (96.1%), diameter (> 1- 3cm) is 58.8%. T-staging by CT showed T1 (35.3%), T2 (37.3%), T3 (17.6%) and T4 (9.8%). N- staging by CT showed N2 (66.7%), N3a- N3b (19.6%). Staging of Nasopharyngeal carcinoma: stage II-III (60.8%), stage IVA-IVB (23.5%) and stage IVC (11.8%). Conclusions: MDCT with a thinner slice thickness and high quality images is able to detect lymph nodes metastasis with small size and those in deep neck area and assess comprehensively the invasion of the tumor. Key words: Nasopharyngeal carcinoma, MDCT

Observation of the Pulp Chamber of Maxillary First Premolars: A Micro-computed Tomographic Study

2020 ◽  
Vol 16 (3) ◽  
pp. 224-230
Author(s):  
Gozde Serindere ◽  
Ceren Aktuna Belgin ◽  
Kaan Orhan
Keyword(s):  
Root Canal ◽  
Age Groups ◽  
Slice Thickness ◽  
Micro Ct ◽  
Micro Computed Tomography ◽  
Pulp Chamber ◽  
Anatomical Structures ◽  
Computed Tomographic ◽  
The Mean ◽  
Chamber Floor

Background: There are a few studies about the evaluation of maxillary first premolars internal structure with micro-computed tomography (micro-CT). The aim of this study was to assess morphological features of the pulp chamber in maxillary first premolar teeth using micro- CT. Methods: Extracted 15 maxillary first premolar teeth were selected from the patients who were in different age groups. The distance between the pulp orifices, the diameter of the pulp and the width of the pulp chamber floor were measured on the micro-CT images with the slice thickness of 13.6 µm. The number of root canal orifices and the presence of isthmus were evaluated. Results: The mean diameter of orifices was 0.73 mm on the buccal side while it was 0.61 mm on palatinal side. The mean distance between pulp orifices was 2.84 mm. The mean angle between pulp orifices was -21.53°. The mean height of pulp orifices on the buccal side was 4.32 mm while the mean height of pulp orifices on the palatinal side was 3.56 mm. The most observed shape of root canal orifices was flattened ribbon. No isthmus was found in specimens. Conclusion: Minor anatomical structures can be evaluated in more detail with micro-CT. The observation of the pulp cavity was analyzed using micro-CT.

scholarly journals Multi-factorial considerations for intra-thoracic lymph node evaluations of healthy cats on computed tomographic images

2021 ◽  
Vol 17 (1) ◽  
Author(s):  
Ninlawan Thammasiri ◽  
Chutimon Thanaboonnipat ◽  
Nan Choisunirachon ◽  
Damri Darawiroj
Keyword(s):  
Lymph Node ◽  
Lymph Nodes ◽  
Ct Images ◽  
Slice Thickness ◽  
Maximum Width ◽  
Post Contrast ◽  
Computed Tomographic ◽  
Contrast Enhanced Ct ◽  
Contrast Enhanced ◽  
Enhanced Ct

Abstract Background It is difficult to examine mild to moderate feline intra-thoracic lymphadenopathy via and thoracic radiography. Despite previous information from computed tomographic (CT) images of intra-thoracic lymph nodes, some factors from animals and CT setting were less elucidated. Therefore, this study aimed to investigate the effect of internal factors from animals and external factors from the CT procedure on the feasibility to detect the intra-thoracic lymph nodes. Twenty-four, client-owned, clinically healthy cats were categorized into three groups according to age. They underwent pre- and post-contrast enhanced CT for whole thorax followed by inter-group evaluation and comparison of sternal, cranial mediastinal, and tracheobronchial lymph nodes. Results Post contrast-enhanced CT appearances revealed that intra-thoracic lymph nodes of kittens were invisible, whereas the sternal, cranial mediastinal, and tracheobronchial nodes of cats aged over 7 months old were detected (6/24, 9/24 and 7/24, respectively). Maximum width of these lymph nodes were 3.93 ± 0.74 mm, 4.02 ± 0.65 mm, and 3.51 ± 0.62 mm, respectively. By age, lymph node sizes of these cats were not significantly different. Transverse lymph node width of males was larger than that of females (P = 0.0425). Besides, the detection score of lymph nodes was affected by slice thickness (P < 0.01) and lymph node width (P = 0.0049). Furthermore, an irregular, soft tissue structure, possibly the thymus, was detected in all juvenile cats and three mature cats. Conclusions Despite additional information on intra-thoracic lymph nodes in CT images, which can be used to investigate lymphatic-related abnormalities, age, sex, and slice thickness of CT images must be also considered.

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