Scan Parameters Research Articles

Development and Clinical Evaluation of a Contrast Optimizer for Contrast-Enhanced CT Imaging of the Liver

Objective Patient characteristics, iodine injection, and scanning parameters can impact the quality and consistency of contrast enhancement of hepatic parenchyma in CT imaging. Improving the consistency and adequacy of contrast enhancement can enhance diagnostic accuracy and reduce clinical practice variability, with added positive implications for safety and cost-effectiveness in the use of contrast medium. We developed a clinical tool that uses patient attributes (height, weight, sex, age) to predict hepatic enhancement and suggest alternative injection/scanning parameters to optimize the procedure. Methods The tool was based on a previously validated neural network prediction model that suggested adjustments for patients with predicted insufficient enhancement. We conducted a prospective clinical study in which we tested this tool in 24 patients aiming for a target portal-venous parenchyma CT number of 110 HU ± 10 HU. Results Out of the 24 patients, 15 received adjustments to their iodine contrast injection parameters, resulting in median reductions of 8.8% in volume and 9.1% in injection rate. The scan delays were reduced by an average of 42.6%. We compared the results with the patients' previous scans and found that the tool improved consistency and reduced the number of underenhanced patients. The median enhancement remained relatively unchanged, but the number of underenhanced patients was reduced by half, and all previously overenhanced patients received enhancement reductions. Conclusions Our study showed that the proposed patient-informed clinical framework can predict optimal contrast enhancement and suggest empiric injection/scanning parameters to achieve consistent and sufficient contrast enhancement of hepatic parenchyma. The described GUI-based tool can prospectively inform clinical decision-making predicting optimal patient's hepatic parenchyma contrast enhancement. This reduces instances of nondiagnostic/insufficient enhancement in patients.

Radiation induced liver injury (RILI) evaluation using longitudinal computed tomography (CT) in image‐guided precision murine radiotherapy

AbstractPurposeWe aim to perform image‐guided, dose‐escalated, well‐controlled liver‐irradiated animal studies and subsequently evaluate radiation induced liver injury (RILI) using longitudinal CT.MethodsEighteen 6–8 weeks mice were divided into three groups: control, 15Gy and 30Gy irradiated groups. The animal protocol was approved by the animal care ethics committee of our institution. Precision radiotherapy started with CT simulation, followed by treatment planning using volumetric modulated arc therapy (VMAT), image guidance with cone beam CT (CBCT) and radiation delivery on a medical linear accelerator. Weekly CT was conducted on the same CT simulator using same scanning parameters. At the end of fifth week, all mice were sacrificed, and histological staining was performed. Body weight, liver volume, HU values and histogram distributions were analyzed.ResultsBody weight of irradiation groups was significantly reduced compared to that of the control group (p<0.05). Liver volume in irradiated groups was reduced too. The average liver HU was significantly reduced in irradiated groups (HU mean = 62±3, 48±6, and 36±8 for the control, 15Gy and 30Gy respectively; p control vs. 15Gy < 0.05, p control vs. 30Gy < 0.05). A linear relationship between liver HU and radiation dose was found. Furthermore, HU histogram changes with time and dose showed not only density but also structure might be affected by radiation. HE and Masson Trichrome staining confirmed histological change and increased collagen deposition in irradiated liver.ConclusionLongitudinal unenhanced CT is a useful imaging tool to evaluate the severity and progression of radiation induced liver injury.

LOCAL DIAGNOSTIC REFERENCE LEVEL BASED ON CLINICAL INDICATIONS IN HEAD CT EXAMINATION

Diagnostic Reference Level (DRL) in Computed Tomography (CT) examination should be developed based on clinical indications because each clinical indication uses different scanning parameters. This study aimed to create Local DRL values based on clinical indications (DRLCIL) in Head CT examinations. A retrospective study was conducted on patients who underwent Head CT examinations with clinical indications of Hemorrhagic Stroke (HS), Non-Hemorrhagic Stroke (NHS), Space Occupying Lesion (SOL) without contrast (SOL –C), SOL with contrast (SOL + C) and trauma. The total number of patients used in this study was 745 patients, patients with clinical indications of HS 231 patients, NHS 163 patients, SOL –C 158 patients, SOL + C 67 patients, and trauma 126 patients. The local DRLCIL value was determined using the 2nd quartile value of each clinical indication. The DRLCIL values obtained for the volume weighted CT dose index (CTDIvol) and dose length product (DLP) were respectively HS (52.9 mGy; 1020.4 mGy.cm), NHS (52.9 mGy; 1046.9 mGy.cm), SOL –C (52.9 mGy; 941.1 mGy.cm), SOL +C (52.9 mGy; 1935.0 mGy.cm), and trauma (52.9 mGy; 1469.9 mGy.cm). The DRLCIL value is relatively lower (except for clinical indications of trauma) than the Indonesian Diagnostic Reference Level (I-DRL) for the type of Non-Contrast Head CT examination with the percentage difference of CTDIvol and DLP respectively being HS (–11.83%; –19.97%), NHS (–11.83%; –17.89%), SOL –C (–11.83%; –26.19%) and SOL +C compared to I-DRL Head CT with contrast (–11.83%; –22.60%). For clinical indications of trauma, the local DRLCIL value from DLP is higher than the I-DRL value, with a percentage difference of 15.29%. However, the local DRLCIL value from CTDIvol is lower, with a percentage difference of –11.83%. Local DRL has been developed at the hospital level and can be used as a recommendation for protocol optimization based on clinical indications. Keywords: X-ray, CT scan, Head CT, diagnostic reference level (DRL), local DRL from clinical indications (DRLCIL).

Joint suppression of cardiac bSSFP cine banding and flow artifacts using twofold phase-cycling and a dual-encoder neural network

BackgroundCardiac bSSFP cine imaging suffers from banding and flow artifacts induced by off-resonance. The work aimed to develop a twofold phase cycling sequence with a neural network-based reconstruction (2P-SSFP+Network) for a joint suppression of banding and flow artifacts in cardiac cine imaging. MethodsA dual-encoder neural network was trained on 1620 pairs of phase-cycled left ventricular (LV) cine images collected from 18 healthy subjects. Twenty healthy subjects and 25 patients were prospectively scanned using the proposed 2P-SSFP sequence. bSSFP cine of a single RF phase increment (1P-SSFP), bSSFP cine of a single RF phase increment with a network-based artifact reduction (1P-SSFP+Network), the averaging of the two phase-cycled images (2P-SSFP+Average), and the proposed method were mutually compared, in terms of artifact suppression performance in the LV, generalizability over altered scan parameters and scanners, suppression of large-area banding artifacts in the left atrium (LA), and accuracy of downstream segmentation tasks. ResultsIn the healthy subjects, 2P-SSFP+Network showed robust suppressions of artifacts across a range of phase combinations. Compared with 1P-SSFP and 2P-SSFP+Average, 2P-SSFP+Network improved banding artifacts (3.85±0.67 and 4.50±0.45 vs 5.00±0.00, P<0.01 and P=0.02, respectively), flow artifacts (3.35±0.78 and 2.10±0.77 vs 4.90±0.20, both P<0.01), and overall image quality (3.25±0.51 and 2.30±0.60 vs 4.75±0.25, both P<0.01). 1P-SSFP+Network and 2P-SSFP+Network achieved a similar artifact suppression performance, yet the latter had fewer hallucinations (two-chamber, 4.25±0.51 vs 4.85±0.45, P=0.04; four-chamber, 3.45±1.21 vs 4.65±0.50, P=0.03; and LA, 3.35±1.00 vs 4.65±0.45, P<0.01). Furthermore, in the pulmonary veins and LA, 1P-SSFP+Network could not eliminate banding artifacts since they occupied a large area, whereas 2P-SSFP+Network reliably suppressed the artifacts. In the downstream automated myocardial segmentation task, 2P-SSFP+Network achieved more accurate segmentations than 1P-SSFP with different phase increments. Conclusions2P-SSFP+Network jointly suppresses banding and flow artifacts while manifesting a good generalizability against variations of anatomy and scan parameters. It provides a feasible solution for robust suppression of the two types of artifacts in bSSFP cine imaging.

PHSOR11 Presentation Time: 9:50 AM: Optimizing Scanning Parameters for MR-Guided Brachytherapy: A Study on MR-Line Marker Positioning in Plastic Sharp Needles

PHSOR11 Presentation Time: 9:50 AM: Optimizing Scanning Parameters for MR-Guided Brachytherapy: A Study on MR-Line Marker Positioning in Plastic Sharp Needles

Optimizing Voltage for Effective X-ray Computed Tomography Scan: A Study on Varied Soil Bulk Densities and Container Sizes

Numerous studies have highlighted the role of X-ray computed tomography (X-ray CT) in understanding root architecture. Nevertheless, setting definitive scanning parameters for diverse soils in varied container sizes remains challenging. This study investigates the influence of X-ray CT system voltage on the penetration capability in diverse soils and container sizes, focusing on two key parameters: (1) gray values, which indicate X-ray attenuation and contribute to image contrast, and (2) signal-to-noise ratio, a measure of image clarity. Five soil samples were collected from various depths within a soil profile to encompass bulk density values ranging from 1.34 to 1.84 g·cm−3 to conduct the experiment. Containers with dimensions of 6 × 6 × 6 cm³, 8 × 8 × 6 cm³, 10 × 10 × 6 cm³, 12 × 12 × 6 cm³, 14 × 14 × 6 cm³, and 16 × 16 × 6 cm³ were used. Voltage levels spanning 75 to 225 kV, in 25-kV increments, were applied to each sample. The observed gray values of the X-ray images were fitted using a logistic model of three parameters. Results showed that increasing voltage leads to enhanced penetration up to a plateau point, irrespective of soil density or container size. This plateau could potentially yield higher quality scans, given that lower voltages result in subdued gray values and reduced image contrast. Notably, it was observed that soil properties, including mineral composition, directly affect image gray values. This study established optimal voltage settings for specific soil types at fixed densities, offering valuable insights for researchers investigating soil–root interactions. Although the current findings are based on five soils, a more extensive sampling encompassing diverse soil textures and densities is necessary for a comprehensive understanding of X-ray penetration behavior across various soil types.

Clinical diagnostic reference levels and image quality metrics for CT in oncology patients

Background: In CT, the volumetric CT dose index (CTDIvol), dose-length product (DLP) and patient’s size-specific dose estimates (SSDE) are used as diagnostic reference level (DRL) metrics.Objectives: To develop clinical local DRL values for CT chest-abdomen-pelvis (CAP) examinations using the CTDIvol, DLP and SSDE, and to determine the image quality achieved.Method: In total, 201 cancer patients were included in the study. The scanning parameters, dose metrics from the CT unit and participants’ body mass index (BMI) were documented. The local CT DRL values for CAP examinations were defined as the median and 75th percentiles of the dose distribution.Results: The local DRL values given in terms of median CTDIvol ranged between 8.4 mGy and 12.7 mGy for the different types of cancers. The median DLPs ranged from 848 to 1173.4 mGy.cm for the various cancers. Generally, the radiation dose was directly proportional to the BMI and number of scan phases. Significant differences were observed between the DRLs for the various size-related parameters, number of scan phases and BMI classifications. The image quality was clinically satisfactory.Conclusion: No baseline data for clinical DRL values were available for this medical oncology department. The achieved DRLs were similar to published size-specific DRLs. The image quality was maintained during CT imaging. Dose optimisation and image quality assessment should be implemented to ensure optimal scanning parameters for different cancers in CT CAP examinations.Contribution: The first size-specific local DRL values for CT CAP investigations carried out on oncology patients in South Africa have been established.

Precontouring as a Tool to Improve the Laser Powder Bed Fusion Printability of Inconel939 Thin Walls

This work investigates the influence of adding a contour scan prior to hatching (precontouring) on the printability of Inconel 939 thin‐wall sections produced by laser powder bed fusion. Walls with thicknesses ranging from 500 to 1500 μm, manufactured with two hatch scanning parameter sets that give rise to different microstructures and very high density in bulk samples of the same alloy, are investigated. It is shown that, while the texture as well as the grain size and shape is only influenced moderately by the contour scanning strategy, precontouring does lead to a significant reduction of the melt pool depth, an effect that is increasingly pronounced with decreasing wall thickness. This work highlights the role of the precontour scan as a heat sink, shifting the normalized enthalpy input toward lower values and thus limiting the accumulation of excess heat. Precontouring is put forward as a scanning strategy to improve the manufacturability of thin sections.

Radiographic Measurements of Pes Planovalgus Do Not Predict Clinical Outcomes in Tarsal Coalition Excision.

Many patients who undergo tarsal coalition excision have persistent postoperative pain. Most studies have utilized cat scan (CT) scan parameters of pes planovalgus and heel valgus but have found this to be an inconsistent predictor of outcomes. Plain radiographic parameters have been less utilized in trying to predict outcomes after coalition excision. Radiographic talonavicular coverage angle correlates with pain in patients with flexible pes planovalgus (PPV) but has not been studied in tarsal coalition population. Furthermore, foot alignment is not understood to change after simple coalition excision. The purpose of this study was to compare plain radiographic parameters, including talonavicular coverage angle, with pain after tarsal coalition excision, as well as compare preoperative and postoperative weight-bearing radiographs. Seventy-seven feet that underwent excision of the tarsal coalition had clinical outcomes and radiographic data collected >1 year postoperatively. Measures of PPV on preoperative and postoperative weight-bearing radiographs and CT scans were evaluated. Patients were an average of 13 years old at excision. Of the total, 65% had calcaneonavicular (CN) coalitions, whereas the remainder had talocalcaneal coalitions. All patients had significant postoperative improvement in clinical outcomes but 34% (13/38) had continued pain at the most recent follow-up, more so in talocalcaneal than CN coalitions (55% vs 26%, P < 0.001). The subset with CN coalitions had more severe preoperative PPV but greater postoperative PPV improvement. Except for a weak correlation between radiographic weight-bearing (anterior-posterior) talus-first metatarsal angle and pain with activity (r = -0.54), there were no other correlations between preoperative radiographic parameters and clinical outcomes. Heel valgus on CT did not correlate with radiographic measurements of PPV or pain. We did not find a correlation of radiographic PPV with persistent pain after tarsal coalition excision. We did find improvement in radiographic PPV in CN coalitions after treatment with simple excision. Heel valgus on CT was not a useful metric for evaluating PPV in the setting of a tarsal coalition. Level III-prognostic study.

A review of intracranial aneurysm imaging modalities, from CT to state-of-the-art MR.

Traditional guidance for intracranial aneurysm (IA) management is dichotomized by rupture status. Fundamental to ruptured aneurysm management is the detection and treatment of subarachnoid hemorrhage, along with securing the aneurysm by the safest technique. On the other hand, unruptured aneurysms first require a careful assessment of natural history versus treatment risk, including an imaging assessment of aneurysm size, location, and morphology, along with additional evidence-based risk factors such as smoking, hypertension, and family history. Unfortunately, a large proportion of ruptured aneurysms are in the lower risk size category (<7mm), putting a premium on discovering a more refined non-invasive biomarker to detect and stratify aneurysm instability prior to rupture. In this review of aneurysm work-up, we cover the gamut of established imaging modalities (e.g., CT, CTA, DSA, FLAIR, 3D-TOF-MRA, CE-MRA) as well as more novel MR techniques (MR-VWI, DCE-MRI, CFD). Additionally, we evaluate the current landscape of AI software and their integration into diagnostic and risk stratification pipelines for IAs. These advanced MR techniques, increasingly complemented with AI models, offer a paradigm shift by evaluating factors beyond size and morphology, including vessel wall inflammation, permeability, and hemodynamics. Additionally, we provide our institution's scan parameters for many of these modalities as reference. Ultimately, this review provides an organized, up-to-date summary on the array of available modalities/sequences for IA imaging to help build protocols focused on IA characterization.ABBREVIATIONS: IA = intracranial aneurysm; LP = lumbar puncture; UIA = unruptured intracranial aneurysm; VWI = vessel wall imaging; 3DRA = 3D Rotational Angiography.

Evaluation of automatic tube current modulation in a CT scanner using a customised homogeneous phantom

Objective.The introduction of automatic tube current modulation (ATCM) has resulted in complex relationships between scanner parameters, patient body habitus, radiation dose, and image quality. ATCM adjusts tube current based on x-ray attenuation variations in the scan region, and overall patient dose depends on a combination of factors. This work aims to develop mathematical models that predict CT radiation dose and image noise in terms of attenuating diameter and all relevant scanner parameters.Approach.A homogenous phantom, equipped with the features to conduct discrete and continuous adaption tests, was developed to model ATCM in a Philips CT scanner. Scanner parameters were varied based on theoretical dose relationships, and a MATLAB script was developed to extract data from DICOM images. R statistical software was employed for data analysis, plotting, and regression modelling.Main Results.Phantom data provided the following insights: Median tube current decreased by 81% as tube potential varied from 80 kVp to 140 kVp. Doubling the DoseRight Index (DRI) from 12 to 24, at 24 cm diameter, produced a 294% increase in mA and a 46% decrease in noise. Mean mA increased by 53% whilst mean noise increased by 5.7% as helical pitch increased from 0.6 to 0.925. Changing rotation time from 0.33s to 0.75s gave a 56% reduction in mean mA and no change in image noise. Increasing detector collimation (n×T) resulted in higher tube currents and lower output image noise values, asnandTwere varied independently. Interpreting these results to apply transformations relevant to each independent variable produced models for tube current and noise with adjusted R-squared values of 0.965 and 0.912, respectively.Significance.The models developed more accurately predict radiation dose and image quality for specific patients and scanner settings. They provide imaging professionals with a practical tool to optimize scan protocols according to patient diameters and clinical objectives.

Decoding the Gaugino Code Naturally at High-Lumi LHCs

Natural supersymmetry with light higgsinos is most favored to emerge from the string landscape, since the volume of a scan parameter space shrinks to tiny volumes for electroweak unnatural models. Rather general arguments favor a landscape selection of soft SUSY breaking terms tilted to large values, but they are tempered by the atomic principle that the derived value of the weak scale in each pocket universe lies not too far from its measured value in our universe. But, that leaves (at least) three different paradigms for gaugino masses in natural SUSY models: unified (as in nonuniversal Higgs models), anomaly mediation form (as in natural AMSB), and mirage mediation form (with comparable moduli- and anomaly-mediated contributions). We perform landscape scans for each of these, and we show that they populate different, but overlapping, positions in m(ℓℓ¯) and m(wino) space. The first of these may be directly measurable at high-lumi LHC via the soft opposite-sign dilepton plus jets plus E/T signature arising from higgsino pair production, while the second of these could be extracted from direct wino pair production, leading to same-sign diboson production.

Reducing Laser Exposure Time of PBF-LB/P by Providing High Energy Without Thermal Degradation and Its Effect on Part Strength and Process Time

Abstract One of the most promising additive manufacturing technologies for the production of end-use parts is powder bed fusion of polymer with laser beam (PBF-LB/P). This technology can reduce production costs by increasing process efficiency and production speed. As PBF-LB/P is a layer-wise additive manufacturing process, the production speed can be increased by reducing the layering time. Although some operations such as recoating are performed during the layering process, considerable time is spent on laser scanning. To reduce the laser exposure time while maintaining proper powder melting, a high-power beam should be irradiated to the powder layer to prevent energy shortage. However, as the laser beam power increases, the irradiance at the beam center increases significantly, causing powder degradation such as thermal decomposition or sublimation. In this study, an appropriate input energy range was determined by obtaining an input energy limit that does not cause powder deterioration via experimental observations and temperature estimations during the process. Furthermore, the influence of the scanning parameters on the mechanical properties of built specimens was investigated to reduce the layering time within an indicated range. Results show that the mechanical strength of the built parts decreases slightly as the scan spacing increases following the expansion of the beam diameter. This study also validated the effects of scanning parameters on layering time. As a result, by doubling the scan speed and spacing, the layering time can be reduced by up to 1/3.

Investigating the effective temporal resolution in a task-based functional MRI experiment at 7 T MRI using a dynamic phantom

Abstract An increasing number of human fMRI studies aim to discern the time delays between evoked responses under different stimuli conditions in different brain regions. To achieve that, a primary goal is to acquire fMRI data with high sampling rates. This task is now possible with ultra-high field (≥7 T) MRI and the advancement of imaging acceleration methods. Consequently, it becomes imperative to understand what is the actual or effective temporal resolution (ETR) that is realized in given settings of an fMRI experiment. In this study, we utilized a dynamic phantom to reliably repeat a set of scans, generating a “ground truth” signal with controllable onset delays mimicking fMRI responses in a task-based block-designed fMRI. Here, we define the ETR and quantify a scan’s ETR using the dynamic phantom. The quantification was performed for various scanning parameters, including echo time (TE), repetition time (TR), voxel size, and contrast-to-noise ratio (CNR). We further show that combining data from multi-echo EPI can improve the ETR (i.e., reduce it). In addition, parameters of the fMRI paradigm were examined, including the blocks’ length and density. As tissue properties (e.g., level of iron deposition) affect the CNR and thus change the ETR, we examined the signal rise mimicking not only the cortex, but also the basal ganglia (known for its high iron deposition). Combining multi-echo data, the estimated ETR for the examined scans was 151 ms for a cortex-mimicking setup and 248 ms for a basal ganglia-mimicking setup, when scanning with a sampling time (i.e., TR) of 600 ms. Yet, a substantial penalty was paid when the CNR was low, in which case the ETR was even larger than the TR. A feasibility set of experiments was also designed to evaluate how the ETR is affected by physiological signal fluctuations and the variability of the hemodynamic response. This study shows the viability of studying time responses with fMRI, by demonstrating that a very short ETR can be achieved. However, it also emphasizes the need to examine the attainable ETR for a particular experiment.

Performance of iodine quantification through high-pitch dual-source photon-counting CT: a phantom study.

To investigate the feasibility and accuracy of iodine quantification using PCD-CT in standard-pitch and high-pitch scanning at different scan parameters in a phantom model. Four inserts with known iodine concentrations (2, 5, 10, and 15mg/mL) were placed in the removable CT phantom and scanned using high-pitch (3.2) and standard-pitch (0.8) modes on PCD-CT. Two tube voltages (120 and 140 kVp) and four radiation doses (1, 3, 5, and 10mGy) were alternated. Each scan setting was repeated three times. Mean iodine concentration for each insert across three consecutive slices was recorded. Percentage absolute bias (PAB) was assessed for iodine quantification. A total of 96 acquisitions were conducted. In small phantom, the average for PAB was 2.96% (range: 1.75% ~ 4.56%) and 1.67% (range: 1.00% ~ 3.42%) for high-pitch and standard-pitch acquisitions, respectively. In large phantom, it was 3.72% (range: 1.75% ~ 5.97%) and 2.94% (range: 1.75% ~ 4.70%). Linear regression analysis revealed that only phantom size significantly influenced (P < 0.001) the accuracy of iodine quantification. The high-pitch scan mode in PCD-CT can be used to quantify iodine density with similar accuracy compared with standard pitch.

On morphology and roughness of upskin surfaces in laser powder-bed fusion additive manufacturing – Contouring strategy effects

The surface quality of inclined parts made by Laser powder-bed fusion (L-PBF) additive manufacturing is inferior to those made by conventional formative and subtractive manufacturing techniques. The inherited step edges formed during such layer-by-layer fabrications and partially melted or non-melted particles attached to the newly formed surface are the major causes of poor surface finish of L-PBF parts. This study is a part of a research framework, in which the effects of different contouring strategies and scan parameters on the surface morphology of inclined parts are investigated by both experimental and numerical methods. In particular, the effect of two different contour scan strategies, namely pre-contouring and post-contouring, on the upskin surface roughness of 30⁰ inclined parts is analyzed. The inclined specimens were fabricated with Ti6Al4V powder using an EOS M270 system and the upskin surfaces were measured by a white light interferometer. In addition, a multi-track multi-layer numerical approach using coupled discrete element method and thermo-fluid simulation was also performed to understand the inclined surface formation in L-PBF.The findings show that the pre-contouring strategy with high linear energy density (LED) (0.4 J/mm) results in average surface roughness (Sa) as low as 7.43 µm, whereas the lowest LED (0.05 J/mm) resulted in the highest Sa of 33.74 µm. Larger melt pool dimensions were obtained in the high LED pre-contouring simulations, which indicates a better material fusion resulting in a good surface finish. The numerical simulation showed that the upskin surface roughness is also affected by the raster scan, if the raster scanning LED is higher than that of pre-contour scans. For the post-contouring strategy studied, higher and lower LEDs were used in inner and outer contour scanning, respectively. It is indicated that the inner contour scanning with a high LED reduces the surface roughness because of a larger melt pool size, irrespective of outer contour scanning. The lowest Sa obtained was 8.24 µm for the highest LED inner contour (0.05 J/mm) case and the highest Sa was 19.95 µm, for the parts made with the lowest LED inner contour scan (0.075 J/mm) strategy. The coupled discrete-element and thermo-fluid-based simulations offer insights into the sloped surface formation and the results supported the experimental findings in qualitative manner.

REVOLUTIONIZING ONCOLOGY IMAGING: A PARADIGM SHIFT THROUGH STANDARDIZED MRI PROTOCOLS: VOLUME 2

Introduction: Oncology imaging is always developing, thus rapid and precise diagnosis are essential for cancer therapy. Recognizing the importance of Magnetic Resonance Imaging, our Mahamana Pandit Madan Mohan Malaviya Cancer Centre is standardizing MRI protocols to improve inspection and interpretation. This project aims to standardize, eliminate variance, and speed up patient care choices. Methods: Our standardized MRI procedures summarize scan parameters, sequences, modes, matrix and other data by body part. A 3 Tesla MRI machine was used to study how scanner differences affect parameters. Detailing appropriate pathological visualization sequences allowed diagnostic versatility. Localiser or scanogram was emphasized for exact scan plane alignment, ensuring uniform pictures for smooth comparisons. Results:Specific procedures were established for certain anatomical locations, with a focus on precise patient placement. Optimizing the localizer setup and selecting the appropriate coil can enhance the quality of images and increase diagnostic accuracy. Discussion: The conversation emphasizes the crucial need of standardizing MRI methods to ensure prompt and precise cancer diagnosis. The benefits of using this technology, such as maintaining consistency, saving time, and improving picture quality, help speed up the diagnostic process and lead to better outcomes for patients. Conclusion: Standardizing MRI procedures is a major step toward efficient and patient-centered cancer imaging, addressing varied oncological issues and improving consistency, time efficiency, and picture quality. Staff training and cooperation put our institution at the forefront of technology advances to improve cancer patient outcomes. We aim to enhance cancer care and treatment via cooperation, improvement, and a patient-centric approach.

Role of diffusion-weighted imaging in the diagnosis of pituitary region tumors.

This study aimed to assess the role of Diffusion-Weighted Imaging (DWI) in routine pituitary Magnetic Resonance Imaging (MRI) protocols for distinguishing sellar and parasellar tumors, addressing the lack of clear guidelines in contemporary literature. A retrospective analysis of 242 pituitary MRI scans with DWI sequences was conducted in a single-center study using a 1.5T scanner and standard DWI sequence parameters. Measurements of both absolute and relative mean apparent diffusion coefficient (ADC) values, along with minimal ADC values within tumors, were performed. The adopted region of interest (ROI) based method used for these measurements was validated. Invasive pituitary adenomas exhibited significantly lower min ADC and min rADC than meningiomas, with optimal cut-off points of 0.64 (sensitivity 73%, specificity 82%) and 0.78 (sensitivity 73%, specificity 89%), respectively. Post-hemorrhagic pituitary adenomas demonstrated lower ADC values than adamantinomatous craniopharyngiomas, with an AUC of 0.893 for min rADC = 1.07, and Rathke's Cleft Cysts with mucous content, AUC 0.8 for min rADC = 1.01. Specific differentiation with high sensitivity and specificity based on diffusion parameters was observed for these tumor groups. Cystic pituitary non-functional adenomas obtained significantly lower ADC values compared to the adamantinomatous type of craniopharyngiomas and serous Rathke's Cleft Cysts (AUC up to 0.942). The study concludes that integrating DWI into routine pituitary MRI protocols enhances diagnostic accuracy in distinguishing sellar and parasellar tumors. The short scan time of one minute makes DWI a valuable and precise tool, supporting its recommendation as a standard component of pituitary MRI examinations.

Quantifying the effect of scanning parameters on digital volume correlation analysis for in situ X-ray imaging of concrete

The potential effects of X-ray Computed Tomography (XCT) scan settings on the kinematic field computed via Digital Volume Correlation (DVC) are discussed in this paper. A parametric sensitivity study was conducted, including a series of acquired XCT scans, probing the same volume of interest (VOI) of a concrete specimen, and applying various combinations of XCT scan settings. Different values were adopted for the number of projections acquired, the exposure time and the pixel size. The DVC results revealed a linear correlation between the mean normalised correlation residuals, designating the quality of the correlation and the reliability of the computed kinematic field and the scanning parameters. Gaussian and median filters were applied to the raw data to explore the effect of image noise smoothness in the DVC analysis. The significant reduction noted for the mean normalised correlation residuals was not accompanied by similar levels of change for the corresponding error uncertainties, as defined by the displacement magnitude. The concept was tested against a realistic loading scenario, where the DVC kinematic fields, computed for various XCT “recipes”, were compared. Slim differences in the distribution of the mean minimum principal strain were observed.

Optimization of magnetic resonance imaging of the hand

BACKGROUND: Magnetic resonance imaging is one of the leading imaging modalities of the musculoskeletal system. However, when imaging the hand, major problems in magnetic resonance imaging include the lack of specialized coils and reliable fixation devices for the hand, uncomfortable patient posture, motion artifacts, and small anatomical structures in the wrist. These factors inevitably lead to incorrect interpretation. AIM: To improve the quality of magnetic resonance imaging of the hand by developing an approach to coil selection, scanning protocol, and hand positioning and fixation. MATERIALS AND METHODS: A positioning device was developed to prevent hand movements. Two types of coils were evaluated. Magnetic resonance images were evaluated comparatively, as well as by a musculoskeletal radiologist. RESULTS: А head coil is more appropriate when scanning the entire hand, for example, in rheumatic diseases. A knee coil is more appropriate when studying smaller anatomical structures (including the wrist) owing to a smaller field of view and higher resolution. Based on the obtained data, guidelines for the selection of scanning parameters, sequences, and coils for magnetic resonance imaging of the hand were formulated. To prevent motion artifacts, a special fixation device of the patient’s hand was introduced. CONCLUSION: Certain factors directly affect the qualitative magnetic resonance imaging study of the hand, such as safety protocols, scanning parameters, and hand fixation. The guidelines presented in this study and the use of the developed specialized fixation device may improve the quality of magnetic resonance imaging of the hand.