Physical analysis of breast cancer using dual-source computed tomography

<h3>Background</h3> Non invasive plaque characterisation is important for risk stratification. Dual Source CT (DSCT) offers a significant improvement in temporal resolution over single source CT and may be a non invasive method to classify plaque components. Although CT plaque images have previously been compared with greyscale IVUS they have not been validated against virtual histology intravascular ultrasound (VH-IVUS), a technology which involves spectral analysis of IVUS radiofrequency signals. VH-IVUS is the gold standard for in vivo plaque classification, with proven validation against histology. Our aim was to show that DSCT could distinguish between plaque components as defined by VH-IVUS on the basis of their attenuation values in Hounsfield units (HU). <h3>Methods</h3> Twenty-one patients underwent DSCT and VH-IVUS prior to coronary stenting. Twenty-six plaques with VH-IVUS plaque burden &gt;40% were chosen. Plaques were either homogenous for fibrous plaque or contained large confluent areas of calcified plaque or a necrotic core. The VH- IVUS images were co-registered with the corresponding CT image by an unblinded observer. Accurate matching of lesions was performed by using measurements of distance from the coronary ostia. The images were orientated using fiduciary markers (side branches or characteristic calcifications). Multiple regions of interest (ROI) were placed within the plaque components and lumen on the cross sectional CT images in areas that had been pre-classified on the VH-IVUS images (Abstract 76 Figure 1). The density of these ROIs were measured (expressed in HU) and assigned to the relative plaque type or lumen. <h3>Results</h3> Attenuation values for 171 ROIs (necrotic core 28, fibrous plaque 38, calcified plaque 29 and lumen 76) were measured from the 26 plaques. Mean and standard deviation attenuation values were 35+/−17 HU, 128+/−49 HU, 719+/−237 HU and 362+/−51 respectively (Abstract 76 Table 1). There were statistically highly significant differences in the attenuation values among the four groups (necrotic core, fibrous plaque, calcified plaque and lumen) by nonparametric Kruskal–Wallis test (p&lt;0.0001) (Abstract 76 Figure 2). <h3>Conclusions</h3> VH-IVUS-defined plaque components have characteristic attenuation values that differ significantly enough to be differentiated by DSCT. This classification may facilitate non-invasive coronary plaque characterisation using DSCT for both therapeutic drug trials and assessment of vascular risk.

Dual-source CT coronary angiography in patients with atrial fibrillation: Comparison with single-source CT

This study aimed to fabricate a heterogeneous phantom replicating the commercial Rando phantom by mixing plaster powder and polylactic acid (PLA) powder. Producing a heterogeneous phantom using Plaster and PLA is cheaper because it can be easily obtained in the commercial market. Additionally, patient-specific Quality Assurance can be easily performed because the phantom can be produced based on the patient’s CT image. PLA has been well studied in the field of radiation therapy and was found to be safe and effective. To match the mean Hounsfield unit (HU) values of the Rando phantom, the bone tissue was changed using plaster and 0–35% PLA powder until an appropriate HU value was obtained, and soft tissue was changed using the PLA infill value until an appropriate HU value was obtained. Bone tissue (200 HU or higher), soft issue (− 500 to 200 HU), and air cavity (less than − 500 HU) were modeled based on the HU values on the computed tomography (CT) image. The bone tissue was modeled as a cavity, and after three-dimensional (3D) printing, a solution containing a mixture of plaster and PLA powder was poured. To evaluate the bone implementation of the phantom obtained by the mixture of plaster and PLA powder, the HU profile of the CT images of the 3D-printed phantom using only PLA and the Rando phantom printed using only PLA was evaluated. The mean HU value for soft tissue in the Rando phantom (− 22.5 HU) showed the greatest similarity to the result obtained with an infill value of 82% (− 20 HU). The mean HU value for bone tissue (669 HU) showed the greatest similarity to the value obtained with 15% PLA powder (680 HU). Thus, for the phantom composed of plaster mixed with PLA powder, soft tissue was fabricated using a 3D printer with an infill value of 82%, and bone tissue was fabricated with a mixture containing 15% PLA powder. In the HU profile, this phantom showed a mean difference of 61 HU for soft tissue and 109 HU for bone tissue in comparison with the Rando phantom. The ratio of PLA powder and plaster can be adjusted to achieve an HU value similar to bone tissue. A simple combination of PLA powder and plaster enabled the creation of a custom phantom that showed similarities to the Rando phantom in both soft tissue and bone tissue.

Retrospective observational study. This study aimed to determine the predictive utility of Hounsfield unit (HU) values, derived from single-slice computed tomography (CT) images, for identifying postoperative pedicle screw (PS) loosening in patients undergoing lumbar interbody fusion. The HU values were specifically measured along the planned PS trajectory. PS loosening is a frequent complication following spinal fusion surgery, particularly in individuals with compromised bone quality. Although prior research has explored the correlation between screw loosening and general vertebral HU values or bone mineral density, the specific predictive capability of a simple, single-slice measurement along the screw path remains a gap in the literature. We retrospectively reviewed data from 47 patients (212 screws) who underwent lumbar interbody fusion between November 2020 and September 2022. Preoperative CT images were used to measure HU values in both the vertebral body and along the PS trajectories. Patients were then stratified into two groups based on the presence (L group, n=9) or absence (no-loosening [NL] group, n=38) of screw loosening identified on 1-year follow-up CT. Comparative analyses were conducted, followed by a receiver operating characteristic curve analysis to establish the optimal predictive HU cutoff. The incidence of postoperative screw loosening was 11.8% (25/212). While no significant inter-group differences were observed regarding age, bone mineral density, or vertebral body HU values, the PS trajectory HU was significantly lower in the L group (111±40) compared to the NL group (157±74) (p <0.001). Receiver operating characteristic curve analysis identified an optimal HU cutoff of 123. The area under the curve was 0.7106, with an odds ratio of 3.18, sensitivity of 0.31, and specificity of 0.41. Lower HU values measured along the PS trajectory using single-slice CT images were significantly associated with a higher risk of screw loosening. This straightforward method may serve as a valuable tool for identifying high-risk patients during the preoperative planning phase of spinal fusion surgery.

BackgroundHybrid imaging combines nuclear medicine imaging such as single photon emission computed tomography (SPECT) or positron emission tomography (PET) with computed tomography (CT). Through this hybrid design, scanned patients accumulate radiation exposure from both applications. Imaging modalities have been the subject of long-term optimization efforts, focusing on diagnostic applications. It was the aim of this study to investigate the influence of an iterative CT image reconstruction algorithm (ASIR) on the image quality of the low-dose CT images.Methodology/Principal FindingsExaminations were performed with a SPECT-CT scanner with standardized CT and SPECT-phantom geometries and CT protocols with systematically reduced X-ray tube currents. Analyses included image quality with respect to photon flux. Results were compared to the standard FBP reconstructed images. The general impact of the CT-based attenuation maps used during SPECT reconstruction was examined for two SPECT phantoms. Using ASIR for image reconstructions, image noise was reduced compared to FBP reconstructions for the same X-ray tube current. The Hounsfield unit (HU) values reconstructed by ASIR were correlated to the FBP HU values(R2 ≥ 0.88) and the contrast-to-noise ratio (CNR) was improved by ASIR. However, for a phantom with increased attenuation, the HU values shifted for low X-ray tube currents I ≤ 60 mA (p ≤ 0.04). In addition, the shift of the HU values was observed within the attenuation corrected SPECT images for very low X-ray tube currents (I ≤ 20 mA, p ≤ 0.001).Conclusion/SignificanceIn general, the decrease in X-ray tube current up to 30 mA in combination with ASIR led to a reduction of CT-related radiation exposure without a significant decrease in image quality.

1692 ANALYSIS OF STONE'S COMPOSITION AND CT DENSITY

PurposeThis study compared Hounsfield unit (HU) values on computed tomography (CT) scans at fractured sites and each vertebral level of the whole spine among three groups: individuals with diffuse idiopathic skeletal hyperostosis (DISH), young individuals without DISH, and older individuals without DISH.MethodsA total of 71 patients with thoracolumbar fracture treated at our hospital from 2011 to 2022 were enrolled. Patients were divided into three groups: those with DISH (22 cases), young without DISH (Y non-DISH; age < 50 years, 24 cases), and older without DISH (O-non-DISH; age ≥ 50 years, 25 cases). The total spine HU values from C2 to S1 were measured from CT axial images, as follows: C2-C6, cervical spine; C7-T4, upper thoracic spine; T5-T9, lower thoracic spine; T10-L2, thoracolumbar spine; and L3-S1, lumbar spine. We compared (1) the HU values between fractured and non-fractured sites in each group (2) the HU values by site within each group, and (3) the HU values at each vertebral level of the whole spine between the three groups.ResultsIn all groups, the mean HU values were significantly higher in the cervical spine than in the other regions (p < .05) and HU values increase at the fracture site (p < .05). The mean HU values for the lower thoracic, thoracolumbar, and lumbar spine were not significantly different in each group. The mean HU values below T6 were significantly lower in the DISH and O-non-DISH groups than in the Y-non-DISH group (p < .05). The mean HU values, except at T3, did not differ significantly between the DISH and O-non-DISH groups.ConclusionAmong patients with thoracolumbar injuries, spinal HU values were lower in older patients with and without DISH than in younger patients.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12891-025-09382-5.

Rotational ankle instability (RAI) is associated with the faster onset of severe ankle osteoarthritis via dysfunction of the anterior talofibular ligament, calcaneofibular ligament, and deltoid ligament. No specific clinical examination is available for RAI, and diagnostic imaging has limitations in evaluating ligament degradation. This study investigated the deltoid ligament degeneration using Hounsfield unit (HU) values on computed tomography (CT) images. Patients were enrolled in this retrospective analysis if they had undergone magnetic resonance imaging (MRI) and CT scans of the ankle. The chronic ankle instability (CAI) group comprised 20 ankles with CAI (9 men, 11 women; mean age, 28.7 years) and the control group comprised 28 ankles (16 men, 12 women, mean age, 41.3 years). The average HU values of the deep posterior tibiotalar ligament (dPTL) that constitutes the deltoid ligament were measured on coronal CT images, and MRI results were used as a reference. All patients were subdivided based on the MRI findings of dPTL injury such as fascicular disruption, irregularity, and the loss of striation. A strong negative correlation was identified between age and HU values for all patients (Spearman ρ = -0.63; P < .001). The mean HU values of the dPTL for participants aged <60 years were 81.0 HU for the control group (21 ankles) and 69.5 HU for the CAI group (P = .0075). No significant differences in the HU values were observed for the dPTL among the MRI subgroups. In addition to the conventional imaging examination such as stress radiographs and MRI, HU measurements of CT images could be useful for quantitatively and noninvasively evaluating degenerative changes in the deltoid ligament for CAI patients to assist the diagnosis of RAI. Level III. case-control study.

A Study on Relationship between Single-Slice Hounsfield Unit(HU) value of the Chinese proximal humerus and Bone Mineral Density(BMD) Using Routine Chest CT and Dual-energy X-ray Absorptiometry(DEXA) was performed.Data were collected from 240 individuals who underwent DEXA and routine chest CT scans (including full images of the proximal humerus) on the same day at 967 Hospitals between January 2019 and December 2021.The method of measuring single-slice HU values of the proximal humerus on routine chest CT scans exhibited high reliability and repeatability (intraclass correlation coefficient > 0.961, P < 0.001).A strong positive correlation was observed between single-slice HU values of the proximal humerus and DEXA results, with the 20-mm HU value demonstrating the highest correlation.Across different BMI groups, the Area Under Curve (AUC) for the 20-mm HU value was consistently the largest (AUC=0.701-0.813,P< 0.05).Therefore, the 20-mm HU value can be considered a reliable reference for the opportunistic screening of low BMD, with reference values of -4HU for underweight individuals, -13HU for normal weight individuals, -7HU for overweight individuals, and -16HU for obese individuals.Values below these thresholds indicate a risk of low BMD.This study enriches the Chinese BMD data and offers a swift and effective approach for opportunistically screening low BMD.

Objectives Several authors hypothesized the usefulness of the non-contrast helical computed tomography (NCHCT) with the determination of stone Hounsfield Unit (HU) values in order to predict urinary stone compositions. Preoperative knowledge of stone composition might be interesting in pre-operative decision-making process. The aim of this study was to evaluate the possible correlation between stone chemical composition and correspondent stone HU value in an in-vivo experience. Methods Forty patients with urinary stones were preoperatively studied with abdominal NCHCT, where stone HU values were reported. Stone chemical composition was obtained in each patient, using the colorimetric method. The HU value of each stone was compared with the correspondent chemical analysis. Results The median HU values of calcium oxalate (n=10), mixed calcium oxalate and phosphate (n=19), calcium phosphate (n=2), uric acid (n=6) and mixed uric acid and calcium oxalate (n=3) stones were 1060 HU [interquartile range (IQR) 743.75–1222.5]; 900 HU (IQR 588.5–1108.5); 774 HU (range 720–828); 371 HU (IQR 361.25–436.25) and 532 HU (range 476–626), respectively. Conclusions Our results confirmed a statistically significant difference of the HU values between calcium and pure uric acid calculi, suggesting a correlation between stone chemical composition and CT-density. Hounsfield unit

Assessment of image quality of 64-row Dual Source versus Single Source CT coronary angiography on heart rate: A phantom study

BackgroundIntravenous thrombolysis (IVT) is a rapid and effective treatment in the early stage of ischemic stroke patients and the purpose of this work is to explore the significance of Hounsfield unit (HU) value in Alberta Stroke Program Early CT Score (ASPECTS) for predicting the clinical prognosis of stroke patients with middle cerebral artery occlusion (MCAO) treated by IVT.MethodsThe 84 stroke patients with MCAO treated by IVT were divided into good prognosis group (48 cases) and poor prognosis group (36 cases). HU ratio and HU difference calculated from non-contrast computed tomography between groups were analyzed.ResultsThe HU ratio of good prognosis group was higher than that in poor prognosis group and the HU difference of good prognosis group was lower than that in poor prognosis group (P < 0.05). The HU ratio and ASPECTS were negatively correlated with the infarct volume, and the HU difference was positively correlated with the infarct volume (P < 0.05). HU difference was an independent risk factor for prognosis of patients with MCAO treated by IVT. The area under the receiver operating characteristic curve of HU ratio and HU difference for prognosis was 0.743 and 0.833 respectively.ConclusionThe HU value changes are related to the clinical prognosis of stroke patients with MCAO treated by IVT, HU value may be a prognostic indicator for stroke patients with MCAO treated by IVT.

Acetabular fractures are among the most challenging orthopaedic fractures, and a high total hip arthroplasty (THA) conversion rate has been reported in older patients with acetabular fractures. Bone quality is a poor prognostic factor after acetabular fracture fixation and has been assessed using computed tomography (CT). However, the relationship between Hounsfield unit (HU) values measured using CT and early acetabular fracture outcomes remains unknown. This study aimed to elucidate the effect of HUs on early acetabular fracture outcomes. 50 consecutive patients who underwent open reduction and internal fixation for acetabular fractures were included. The mean follow-up duration was 24 months. 27 hips had elementary fractures and 23 had associated fractures. The reduction quality assessed using CT was as follows: anatomical, 13 hips; imperfect, 10 hips; and poor, 27 hips. Secondary hip osteoarthritis was observed in 5 patients (10%), and the surgery was converted to THA in 1 patient (2%). The HU values of the fifth vertebral body and the unaffected side of the femoral head were measured. The fracture type, radiological secondary hip osteoarthritis, conversion to THA, and postoperative displacement gap were recorded. The unaffected femoral head HU values in elementary fractures (250.5 ± 50.5) were significantly higher than those in associated fractures (221.5 ± 48) (p < 0.047). The HU values of the fifth vertebral body and the unaffected femoral head were significantly correlated with the postoperative residual displacement gap and were significantly lower in those with secondary osteoarthritis than in those without it. The cut-off value for predicting early osteoarthritic change after an acetabular fracture was approximately 180. The HU values were correlated with the fracture type, postoperative displacement gap, and early osteoarthritic change after acetabular fractures and are clinically useful prognostic factors for early acetabular fracture outcomes.

Anterior cruciate ligament (ACL) rupture and patellar dislocation (PD) are common knee injuries. Dual-energy X-ray absorptiometry (DXA) and computed tomography (CT) are widely used clinical diagnostic tools. The aim was to investigate the characteristics of knee bone mineral density (BMD) in patients with ACL rupture and PD and to explore the relationship between BMD and Hounsfield unit (HU) values. This prospective cross-sectional study included 32 ACL rupture and 32 PD patients assessed via DXA and CT. BMD and CT measurements were taken from regions of interest in the femoral and tibial condyles. Statistical analyses included t-tests and mixed-effects models. The results showed that BMD in the PD group was significantly lower than in the ACL group (p < 0.05). The HU values of cortical bone in the femur and tibia differed significantly between the ACL group and the PD group (p < 0.05). The BMD of the femur and tibia showed significant correlations with the HU values of cancellous bone and cortical bone (p < 0.05). The conclusion was that PD patients had lower BMD and HU values in the femur and tibia compared to patients with ACL ruptures, particularly in the cortical bone of the tibia, and there was a strong correlation between HU value and BMD.

192. Evaluation of a commercial orthopedic metal artefact reduction tool in radiation therapy