Effect of gradient strength and bandwidth on slice thickness

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.

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IMAGING CHARACTERISTIS OF MDCT IN NASOPHARYNGEAL CARCINOMA

Journal of Medicine and Pharmacy ◽

10.34071/jmp.2014.4_5.22 ◽

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

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

Current Medical Imaging Formerly Current Medical Imaging Reviews ◽

10.2174/1573405615666191016125937 ◽

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.

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

BMC Veterinary Research ◽

10.1186/s12917-021-02771-7 ◽

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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Influence of Slice Thickness and Culture Conditions on the Metabolism of 7-Ethoxycoumarin in Precision-cut Rat Liver Slices

Alternatives to Laboratory Animals ◽

10.1177/026119299802600417 ◽

1998 ◽

Vol 26 (4) ◽

pp. 541-548

Author(s):

Roger J. Price ◽

Anthony B. Renwick ◽

Paula T. Barton ◽

J. Brian Houston ◽

Brian G. Lake

Keyword(s):

Gas Phase ◽

Rat Liver ◽

Xenobiotic Metabolism ◽

Culture Conditions ◽

Slice Thickness ◽

Dependent Manner ◽

Sprague Dawley ◽

Liver Slices ◽

Sprague Dawley Rats ◽

Rat Livers

This study investigated the effects of some experimental variables on the rate of xenobiotic metabolism in precision-cut rat liver slices. Liver slices of 123 ± 8μm (mean ± SEM of six slices), 165 ± 3μm, 238 ± 6μm and 515 ± 14μm thickness were prepared from male Sprague-Dawley rats, and incubated in RPMI 1640 medium in an atmosphere of 95% O2/5% CO2 by using a dynamic organ culture system. Liver slices of all thicknesses metabolised 10μM 7-ethoxycoumarin to total (free and conjugated) 7-hydroxycoumarin in a time-dependent manner. The rate of 7-ethoxycoumarin metabolism was greatest in 165μm thick slices and slowest in 515μm thick slices, being 2.74 ± 0.19pmol/minute/mg slice protein and 0.69 ± 0.07pmol/minute/mg slice protein, respectively. No marked effects on the rate of 7-ethoxycoumarin metabolism in liver slices were observed either by changing the medium to Earle's balanced salt solution (EBSS) or by changing the gas phase to 95% air/5% CO2. Moreover, the perfusion of rat livers with EBSS at 2–4°C, prior to preparation of tissue cores, did not enhance 7-ethoxycoumarin metabolism in rat liver slices. In this study, the optimal slice thickness was 175μm, with higher rates of 7-ethoxycoumarin metabolism being observed than with 250μm thick slices, which are often used for studies of xenobiotic metabolism. Variable results were obtained with slices of around 100–120μm thickness, which may be attributable to the ratio between intact hepatocytes and cells damaged by the slicing procedure in these very thin slices.

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

Scientific Reports ◽

10.1038/s41598-021-88116-8 ◽

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.

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Study of color kinetics of banana (Musa cavendish) under microwave drying by application of image analysis

Food Science and Technology International ◽

10.1177/1082013220981334 ◽

2020 ◽

pp. 108201322098133

Author(s):

Sagar Nagvanshi ◽

Subbarao Kotra Venkata ◽

TK Goswami

Keyword(s):

Microwave Power ◽

Vision System ◽

Power Level ◽

Microwave Drying ◽

Slice Thickness ◽

Order Kinetic ◽

Drying Time ◽

Volumetric Heating ◽

Kinetics Of ◽

Microwave Power Level

Microwave drying works on the volumetric heating concept promoted by electromagnetic radiation at 0.915 or 2.450 GHz. In this study, banana ( Musa Cavendish) was taken as the sample and treated under microwave drying. The effect of two process variables, namely slice thickness (2, 3.5, and 5 mm) and microwave power (180 W, 360 W, and 540 W), were studied on drying kinetics and color kinetics. It was observed that the inverse variation relationship exists between drying time and microwave power level while drying time and slice thickness exhibited a direct variation relationship. A Computer Vision System (CVS) was developed to measure the color values of banana in CIELab space using an algorithm written in MATLAB software. Once the color parameters were obtained, they were fitted in First and Zero-order kinetic models. Both models were found to describe the color values adequately. This study concludes that microwave drying is a promising dehydration technique for banana drying that reduces the significant time of drying. Application of CVS is an excellent approach to measure the surface color of banana.

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Endograft Planning without Preoperative Arteriography: A Clinical Feasibility Study

Journal of Endovascular Therapy ◽

10.1177/152660280000700102 ◽

2000 ◽

Vol 7 (1) ◽

pp. 8-15 ◽

Cited By ~ 35

Author(s):

Hugh G. Beebe ◽

Boonprasit Kritpracha ◽

Sharon Serres ◽

John P. Pigott ◽

Charles I. Price ◽

...

Keyword(s):

3D Model ◽

Preoperative Evaluation ◽

Spiral Ct ◽

Side Branch ◽

Aortic Aneurysms ◽

Slice Thickness ◽

Technical Success Rate ◽

3 Dimensional ◽

Procedural Time ◽

Procedural Success

Purpose: To investigate an alternative method of preprocedural planning for aortic endografting based solely on spiral computed tomography (CT) with 3-dimensional (3D) reconstruction without preoperative arteriography. Methods: From August 1997 to April 1998, 25 consecutive patients with abdominal aortic aneurysms (AAA) were evaluated for endovascular repair by spiral CT scans (2-mm slice thickness) and computerized 3D model construction. No additional imaging for planning was performed. The aortoiliac dimensions, thrombus load, calcification, and vessel tortuosity were measured and evaluated from the 3D model of the aortoiliac segment. These data were used for selecting the patients; the configuration, diameter, and length of the endograft; and the attachment sites for deployment. Results: Primary procedural success was 92% (23/25). All endografts were deployed as planned, and there were no conversions to open repair. Six patients required adjunctive procedures for delivery system access or for iliac aneurysm exclusion, as predicted by the 3D model. Mean procedural time was 91 minutes (range 24 to 273). Two (8%) type II (side branch) endoleaks both sealed spontaneously within 1 month. No graft-related complications or death occurred, for a 30-day technical success rate of 100%. Conclusions: This computerized 3D model provided accurate data for preoperative evaluation of the aortoiliac segment for endovascular AAA repair. Satisfactory technical outcomes for aortic endografts can be achieved without the use of preprocedural invasive imaging.

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Robustness of radiomic features in CT images with different slice thickness, comparing liver tumour and muscle

Scientific Reports ◽

10.1038/s41598-021-87598-w ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Lorena Escudero Sanchez ◽

Leonardo Rundo ◽

Andrew B. Gill ◽

Matthew Hoare ◽

Eva Mendes Serrao ◽

...

Keyword(s):

Large Fraction ◽

Therapy Response ◽

Response Assessment ◽

Ct Images ◽

Optimal Number ◽

Image Features ◽

Liver Tumour ◽

Slice Thickness ◽

Invasive Method ◽

Feature Values

AbstractRadiomic image features are becoming a promising non-invasive method to obtain quantitative measurements for tumour classification and therapy response assessment in oncological research. However, despite its increasingly established application, there is a need for standardisation criteria and further validation of feature robustness with respect to imaging acquisition parameters. In this paper, the robustness of radiomic features extracted from computed tomography (CT) images is evaluated for liver tumour and muscle, comparing the values of the features in images reconstructed with two different slice thicknesses of 2.0 mm and 5.0 mm. Novel approaches are presented to address the intrinsic dependencies of texture radiomic features, choosing the optimal number of grey levels and correcting for the dependency on volume. With the optimal values and corrections, feature values are compared across thicknesses to identify reproducible features. Normalisation using muscle regions is also described as an alternative approach. With either method, a large fraction of features (75–90%) was found to be highly robust (< 25% difference). The analyses were performed on a homogeneous CT dataset of 43 patients with hepatocellular carcinoma, and consistent results were obtained for both tumour and muscle tissue. Finally, recommended guidelines are included for radiomic studies using variable slice thickness.

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Building Large-Scale Quantitative Imaging Databases with Multi-Scale Deep Reinforcement Learning: Initial Experience with Whole-Body Organ Volumetric Analyses

Journal of Digital Imaging ◽

10.1007/s10278-020-00398-y ◽

2021 ◽

Vol 34 (1) ◽

pp. 124-133

Author(s):

David J. Winkel ◽

Hanns-Christian Breit ◽

Thomas J. Weikert ◽

Bram Stieltjes

Keyword(s):

Reinforcement Learning ◽

Repeated Measures ◽

Quantitative Imaging ◽

Left Kidney ◽

Left Lung ◽

Whole Body ◽

Computational Time ◽

Slice Thickness ◽

Multi Scale ◽

Body Organ

AbstractTo explore the feasibility of a fully automated workflow for whole-body volumetric analyses based on deep reinforcement learning (DRL) and to investigate the influence of contrast-phase (CP) and slice thickness (ST) on the calculated organ volume. This retrospective study included 431 multiphasic CT datasets—including three CP and two ST reconstructions for abdominal organs—totaling 10,508 organ volumes (10,344 abdominal organ volumes: liver, spleen, and kidneys, 164 lung volumes). Whole-body organ volumes were determined using multi-scale DRL for 3D anatomical landmark detection and 3D organ segmentation. Total processing time for all volumes and mean calculation time per case were recorded. Repeated measures analyses of variance (ANOVA) were conducted to test for robustness considering CP and ST. The algorithm calculated organ volumes for the liver, spleen, and right and left kidney (mean volumes in milliliter (interquartile range), portal venous CP, 5 mm ST: 1868.6 (1426.9, 2157.8), 350.19 (45.46, 395.26), 186.30 (147.05, 214.99) and 181.91 (143.22, 210.35), respectively), and for the right and left lung (2363.1 (1746.3, 2851.3) and 1950.9 (1335.2, 2414.2)). We found no statistically significant effects of the variable contrast phase or the variable slice thickness on the organ volumes. Mean computational time per case was 10 seconds. The evaluated approach, using state-of-the art DRL, enables a fast processing of substantial amounts irrespective of CP and ST, allowing building up organ-specific volumetric databases. The thus derived volumes may serve as reference for quantitative imaging follow-up.

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