Computed Tomography Scan Slices Research Articles

Computed Tomography of Cerebral Contusions in Children Younger Than 3 Years

Background: Cerebral contusions occur in approximately 43% of blunt head trauma cases. The gyri are predominantly affected, although severe traumatic brain injury (TBI) may damage the subcortical white matter and deep structures within the brain. Computed tomography (CT) of the brain is used to evaluate all forms of intracranial injuries, fractures, cerebral edema, and other associated injuries.Objective: To analyze the CT potential in the diagnosis of cerebral contusions during the acute phase of TBI in children younger than 3 years.Materials and methods: In 2021-2022 we performed CT using a Philips Ingenuity Elite 128 slice CT scanner in 1334 children with TBI (730 boys and 604 girls younger than 3 years). The area of interest in the examined children was the skull and cervical spine. We did not use enhancement. The effective dose range varied from 1.27 to 1.91 mSv.Results: Of 510 children, 448 (87.84%) patients had skull fractures that combined with intracranial injuries in 366 (81.7%) children, with 262 (71.58%) of them having severe injuries (Glasgow Coma Scale ≤ 8) and 36 (9.83%) of them undergoing surgery. Cerebral contusions were diagnosed in 58.5% (214 of 366) of children. Contusions (98% of which were hemorrhagic) had different volumes and degrees of hemorrhage and edema. The foci of contusions were in the frontal (37.1%), temporal (34.3%), parietal (20.6%), and, less often, occipital (8%) lobes.Conclusions: CT is the preferred imaging modality in acute TBI, which enables to accurately detect and adequately treat cerebral contusions, preventing secondary injuries. CT is the main diagnostic tool and should be performed in all children with TBI within the first hours after injury.

Study on Assessment of the Diameter of Thoracic Aorta by Computed Tomography of Chest

INTRODUCTION: Computed tomography (CT) is frequently used for the evaluation of different aortic diseases which is a good method of measuring the aortic diameter. Thus, knowledge of normal aortic diameters is very important in the assessment of aortic disease.
 METHODS: This was a prospective cross sectional study done on 105 patients who presented in department of Radiodiagnosis in Lumbini Medical College, Palpa, Nepal from February 5th 2022 to February 4th 2023. Plain helical scan was performed using Siemens Somatom 16 slice CT scanner. CT images were obtained in supine position with full inspiration. Diameters of the aorta was measured at the level of aortic valve sinus, ascending aorta, proximal to innominate artery, transverse aortic arch, distal transverse aortic arch, aortic isthmus and descending aorta at the level of diaphragm perpendicular to the axis of the aorta.
 RESULTS: Diameter of thoracic aorta was found to be maximum at ascending aorta with mean of 2.85 cm, followed by aortic valve sinus 2.80 cm, 2.68 cm at proximal to innominate artery, 2.57 cm at proximal transverse arch, 2.41 cm at distal transverse arch, 2.24 cm at isthmus and 2.03 cm at descending aorta at the level of diaphragm. There was smooth tapering of aortic diameter from ascending aorta onwards. There was a significant correlation of mean ascending aorta diameter with the age of the patients(r = 0.475, p< 0.05).
 CONCLUSION: Diameter of thoracic aorta was found to be maximum at the level of the ascending aorta and minimum at the level of diaphragm. The diameter of thoracic aorta had significant correlation with the age of patients.

Quality improvement of images with metal artifact reduction using a noise recovery technique in computed tomography.

In metal artifact reduction (MAR) in computed tomography (CT) based on projection data inpainting, X-ray photon noise has not been considered in the inpainting process. This study aims to assess the effectiveness of a MAR technique incorporating noise recovery in such projection data regions, compared with existing MAR techniques based on projection data normalization (NMAR), including one with frequency splitting (FSNMAR). Phantoms simulating hip prostheses and dental fillings were scanned using a 64-row multi slice CT scanner. The projection data was processed by NMAR and NMAR with noise recovery (NRNMAR); the processed data was sent back to the CT system for reconstruction. For the phantoms and clinical cases with hip prostheses and dental fillings, images were reconstructed without MAR, and with NMAR, NRNMAR, and FSNMAR (incorporated in the CT system). To validate the efficacy of noise recovery, noise power spectra (NPSs) were measured from the images of the hip prosthesis phantom with and without metals. The artifact index (AI) was compared between NRNMAR and FSNMAR. The resultant NPSs of NRNMAR were very similar to those of phantom images with no metals, endorsing the efficacy of noise recovery. The NMAR images had unnatural noise textures and FSNMAR caused additional streaks. NRNMAR exhibited some significant improvements in these respects: It reduced the AI by as much as 66.2-88.6% compared to FSNMAR, except for the case of a unilateral prosthesis. In conclusion, NRNMAR, which simply adds white noise to the projection data, would be effective in improving the quality of CT images with metal artifacts reduction.

Higher Computed Tomography (CT) Scan Resolution Improves Accuracy of Patient-specific Mandibular Models When Compared to Cadaveric Gold Standard

3D-printed patient-specific anatomical models are becoming an increasingly popular tool for planning reconstructive surgeries to treat oral cancer. Currently there is a lack of information regarding model accuracy, and how the resolution of the computed tomography (CT) scan affects the accuracy of the final model. The primary objective of this study was to determine the CT z-axis resolution necessary in creating a patient specific mandibular model with clinically acceptable accuracy for global bony reconstruction. This study also sought to evaluate the effect of the digital sculpting and 3D printing process on model accuracy. This was a cross-sectional study using cadaveric heads obtained from the Ohio State University Body Donation Program. The first independent variable is CT scan slice thickness of either 0.675, 1.25, 3.00, or 5.00mm. The second independent variable is the three produced models for analysis (unsculpted, digitally sculpted, 3D printed). The degree of accuracy of a model as defined by the root mean square (RMS) value, a measure of a model's discrepancy from its respective cadaveric anatomy. All models were digitally compared to their cadaveric bony anatomy using a metrology surface scan of the dissected mandible. The RMS value of each comparison evaluates the level of discrepancy. One-way ANOVA tests (P<.05) were used to determine statistically significant differences between CT scan resolutions. Two-way ANOVA tests (P<.05) were used to determine statistically significant differences between groups. CT scans acquired for 8 formalin-fixed cadaver heads were processed and analyzed. The RMS for digitally sculpted models decreased as slice thickness decreased, confirming that higher resolution CT scans resulted in statistically more accurate model production when compared to the cadaveric gold standard. Furthermore, digitally sculpted models were significantly more accurate than unsculpted models (P<.05) at each slice thickness. Our study demonstrated that CT scans with slice thicknesses of 3.00mm or smaller created statistically significantly more accurate models than models created from slice thicknesses of 5.00mm. The digital sculpting process statistically significantly increased the accuracy of models and no loss of accuracy through the 3D printing process was observed.

Evaluation of the Evan’s and Bicaudate index for South Karnataka Population using computed tomography

Background: Radiological markers that are useful in the diagnosis of normal pressure hydrocephalus include the Bicaudate index (BCI) and the Evans index (EI), which are practical indicators of ventricular volume. Worldwide, variation exists in normative studies for both these indices. The majority of research for EI and BCI is based on data from the Western population. The study has been performed on the South Karnataka population. Aims and Objectives: This study’s goal is to derive age and gender specific cutoff values on normative data of Evans and BCI. Materials and Methods: This was a prospective and observational study.Patients referred to “RL Jalappa Hospital” for computed tomography (CT) scan of the brain who meet the inclusion criteria will be included in this study. CT brain of all the patients will be performed in Siemens Somatom emotion 16 slice CT scanner. Ninety-seven were selected for this study, and EI and BCI were calculated for them. Results: The mean value of EI and BCI in our study was 0.26±0.02 and 0.1167±0.02, respectively. The difference in EI and BCI between males and females shown significant statistical difference between males and females but the values increased as increase in age. Conclusion: Our study for South Indian population concludes that EI and BCI have a significant statistical difference between males and females. Both EI and BCI values increase with age. Hence cutoff values of EI and BCI index according to age and gender are important for evaluation of hydrocephalus.

Role of ultra-low dose computed tomography (CT) in COVID-19 suspected patients: A cross sectional study

Background: This study aims to evaluate the accuracy of ultra-low-dose CT in detecting COVID 19 related chest findings in COVID 19 suspected patients. Materials and Methods: 106 COVID 19 infection suspected patients who are referred for HRCT chest screening, were evaluated by CT using 128 slice CT scanner (Wipro GE Optima 660). Ultra low dose CT with kv 120 & mA 10 was used. The Ground glass opacities and consolidations will be assessed in every lobe and the severity and grading will be done. CT severity score - in this both lungs are divided into five lobes, and each lobe was assessed individually. Each lobe could be awarded a CT score from 0 to 5, depending on the percentage of the involved lobe. All the values of each lobe is added and graded as mild (0-8), moderate (8-15) and severe (15-25). Then we will correlate the ultra low dose CT findings with RT-PCR results. Results: Among the study population with RT-PCR positive, 67 (85.9%) of them ground glass opacity was present and 11 (14.1%) of them absent. The difference in proportion of Ground glass opacity between RT-PCR was statistically significant (p value

Evaluation of grouped capsule network for intracranial hemorrhage segmentation in CT scans

Intracranial hemorrhage is a cerebral vascular disease with high mortality. Automotive diagnosing and segmentation of intracranial hemorrhage in Computed Tomography (CT) could assist the neurosurgeon in making treatment plans, which improves the survival rate. In this paper, we design a grouped capsule network named GroupCapsNet to segment the hemorrhage region from a Non-contract CT scan. In grouped capsule network, we constrain the prediction capsules for output capsules produced from different groups of input capsules with various types in each layer. This method can reduce the number of intermediate prediction capsules and accelerate the capsule network. In addition, we modify the squashing function to further accelerate the forward procedure without sacrificing its performance. We evaluate our proposed method with a collected dataset containing 210 intracranial hemorrhage CT scan slices. In experiments, our proposed method achieves competitive results in intracranial hemorrhage area segmentation compared to the existing methods.

Role of Multidetector Computed Tomography in the Evaluation of Maxillofacial Trauma.

Maxillofacial fractures are among the commonest injuries occurring in trauma patients. Multislice computed tomography (CT) is a widely used radiological investigation that accurately reveals the number, location, and extent of the fractures as well as concomitant soft tissue injuries and has been found to be superior in the diagnosis of maxillofacial fractures owing to high sensitivity and specificity. This study was performed to assess the efficacy of axial, coronal, sagittal, and three-dimensional (3D) reformatted images in the detection of fractures in maxillofacial trauma. This was a cross-sectional descriptive study conducted on 49 adult patients with maxillofacial injuries undergoing multislice CT using a multidetector SiemensSOMATOM Emotion eco 16 slice CT scanner (Siemens AG, Munich, Germany). CT protocol consisted of non-contrast axial 16-slice helical series beam collimation ~ 3 mm, pitch ~ 0.8 - 1, tube current ~ 270 mAs, voltage ~ 130 kV, Total exposure time ~ 18 seconds, total radiation ~ 200 mGy. Along with the axial, coronal and sagittal images were reconstructed with 0.5 mm increment. 3D volume-rendering images were also obtained. 3D images were compared with axial images, coronal and sagittal plane images. The maximum number of cases was in the age group of 21-30 years with the male: female ratio being 5.12:1. The most common cause of injury was road traffic accidents (RTA). Mandible fractures were found to be the most common (20 patients, 40.8%) followed by fractures of nasal bone (18 patients, 36.7%). The incidence of frontal bone fractures was found to be the least(six patients, 12.24%). Our study found that 3D images are superior to axial in assessing the extent and degree of displacement of maxillofacial fractures in general. The maxillary sinus was found to be the most commonly fractured sinus (19 patients, 38.7%). Sphenoid sinus fractures were the least common (seen in two patients, 4.08%). CT findings correlated with the operative findings in most types of fractures. Multidetector CT with multiplanar and 3D reformation is highly accurate in the identification of fractures and assessing the extent and degree of displacement of fractures; hence, it is the imaging modality of choice in maxillofacial trauma.3D images are much better for the detection of maxillofacial fracturescompared to axial, coronal, or sagittal views, especially in maxilla and mandibular bone fractures. It is also found to be betterat providing information on thepatterns of the fracture lines and the displacement of the fracture fragments. Another added advantage of multidetector CT is that it is a non-invasive technique with good accuracy and a short scan time.

Grayscale Image Statistical Attributes Effectively Distinguish the Severity of Lung Abnormalities in CT Scan Slices of COVID-19 Patients.

Grayscale statistical attributes analysed for 513 extract images taken from pulmonary computed tomography (CT) scan slices of 57 individuals (49 confirmed COVID-19 positive; eight confirmed COVID-19 negative) are able to accurately predict a visual score (VS from 0 to 4) used by a clinician to assess the severity of lung abnormalities in the patients. Some of these attributes can be used graphically to distinguish useful but overlapping distributions for the VS classes. Using machine and deep learning (ML/DL) algorithms with twelve grayscale image attributes as inputs enables the VS classes to be accurately distinguished. A convolutional neural network achieves this with better than 96% accuracy (only 18 images misclassified out of 513) on a supervised learning basis. Analysis of confusion matrices enables the VS prediction performance of ML/DL algorithms to be explored in detail. Those matrices demonstrate that the best performing ML/DL algorithms successfully distinguish between VS classes 0 and 1, which clinicians cannot readily do with the naked eye. Just five image grayscale attributes can also be used to generate an algorithmically defined scoring system (AS) that can also graphically distinguish the degree of pulmonary impacts in the dataset evaluated. The AS classification illustrated involves less overlap between its classes than the VS system and could be exploited as an automated expert system. The best-performing ML/DL models are able to predict the AS classes with better than 99% accuracy using twelve grayscale attributes as inputs. The decision tree and random forest algorithms accomplish that distinction with just one classification error in the 513 images tested.

Multidetector computed tomography in evaluation of buccal mucosa cancer

Background: Squamous cell carcinoma is the most prevalent kind of tumor of the buccal mucosa. For the purpose of planning surgery and radiotherapy for tumors of the tongue, floor of the mouth, and oropharyx, imaging to locate the size and extent of the original tumor is essential. Therefore, it is beneficial to determine the radiation field, to ensure adequate tumor margin excision, and overall to improve the patient’s prognosis. Aims and Objectives: The aim of the study was to evaluate the role of computed tomography (CT) scan in diagnosis of buccal mucosal malignancies and its characteristics. Materials and Methods: Total 50 patients suspecting buccal mucosa cancer were referred to Radiology Department. They were subjected for CT scan examination on 16 slice CT scanner. CT scan evaluation was made for size and extent of primary mass lesion. The staging of disease was performed with TNM classification. Results: In our study, out of 50 patients, the fourth decade (30%) and fifth decade (26%) saw the highest incidence of buccal mucosa cancer. The majority of the patients were suffering from severe disease; 44% had T4 stage and 58% had Stage IV. Conclusion: CT plays a very important role in staging of buccal mucosa malignancy and effectively detects bone erosion (98% sensitive) and invasion to infratemporal fossa. However, during the early stages of cancer, a CT scan might not be very helpful.

Computed Tomography Scan Findings in Various Modes of Head Injury, Using GE Optima 128 Slice CT Scanner`

Background: Head injury is a global health problem that can cause disability and may result in death. CT scan detects and precisely localizes the skull fractures, epidural/subdural/subarachnoid hemorrhages, brain contusions and cerebral edema etc. CT has proven to be a valuable tool in the early diagnosis and prompt management of head trauma patients and has resulted in significant improvement in morbidity and mortality. Methods: A descriptive cross-sectional study, including 380 patients, presented to Radiology Department of Hayatabad Medical Complex with a history of head trauma for computed tomography examination, from October 2019 to October 2020. The nature of the brain and skull lesions was analyzed in our study and the frequency of various findings was recorded. Results: Among 380 patients, the majority were males (248) making the male to female ratio to be around 2:1. The most prevalent finding was skull fractures (23.4%) followed by cerebral contusions (17.1%). Among extra-axial brain hemorrhages, extradural hematoma (15.2%) was observed more than subdural hematoma (6.8%) while only 3.4% presented with subarachnoid hemorrhages which also included intraventricular hemorrhages. Practical Implication: As road traffic accidents are the most common cause of head injuries so road traffic safety measures ought to be strictly enforced. Most of the CT scan done during head injuries were normal so CT guidelines for ordering should be implemented to scale back extra patient irradiation, unnecessary waste of resources and a further burden on the radiology department. Keywords: Head Injury, Computed Tomography (CT), Road Traffic Accidents (RTA), Skull Fractures, Epidural Hematoma.

3D Printing Technology for Chest Wall Reconstruction With a Sternum-Ribs-Cartilage Titanium Implant: From Ideation to Creation.

We describe the use of 3-dimensional (3D) printing technology to plan and reconstruct the sternum, adjoining cartilages, and ribs with a custom-made, anatomically designed, 3D-printed titanium implant for an isolated sternal metastasis complicated with a pathological fracture. We imported submillimeter slice computed tomography scan data into Mimics Medical 20.0 software and by manual bone threshold segmentation created a 3D virtual model of the patient's chest wall and tumor. For all-around tumor-free margins, we grew the tumor by 2 cm. The replacement implant was designed in 3D using the anatomical features of the sternum, cartilages, and ribs and manufactured using TiMG 1 powder fusion technology. Physiotherapy was provided prior to and following surgery, and the impact of reconstruction on pulmonary functions was assessed. At surgery, the precise resection, clear margins, and a secure fit were achieved. At follow-up, there was no dislocation, paradoxical movement, change in performance status, or dyspnea. There was a decrease in forced expiratory volume in 1 s (FEV1) from 105% prior to surgery to 82% following surgery and in forced vital capacity (FVC) from 108% to 75%, with no difference in the FEV1/FVC ratio, suggesting a restrictive pattern of impairment. With 3D printing technology, reconstructing a large anterior chest wall defect with a custom-made, anatomical, 3D-printed titanium alloy implant is feasible and safe, and it preserves the shape, structure, and function of the chest wall, albeit with a restrictive pattern of pulmonary function, which can be addressed with physiotherapy.

Computed Tomography Scan Findings in Various Modes of Head Injury, Using GE Optima 128 Slice CT Scanner`

Background: Head injury is a global health problem that can cause disability and may result in death. CT scan detects and precisely localizes the skull fractures, epidural/subdural/subarachnoid hemorrhages, brain contusions and cerebral edema etc. CT has proven to be a valuable tool in the early diagnosis and prompt management of head trauma patients and has resulted in significant improvement in morbidity and mortality. Methods: A descriptive cross-sectional study, including 380 patients, presented to the radiology department of Hayatabad medical complex witha history of head trauma for computed tomography examination, from October 2019 to October 2020. The nature of the brain and skull lesions was analyzed in our study and the frequency of various findings was recorded. Results: Among 380 patients, the majority were males (248) making the male to female ratio to be around 2:1. The most prevalent finding was skull fractures (23.4%) followed by cerebral contusions (17.1%). Among extra-axial brain hemorrhages, extradural hematoma (15.2%) was observed more than subdural hematoma (6.8%) while only 3.4% presented with subarachnoid hemorrhages which also included intraventricular hemorrhages. Practical Implication: As road traffic accidents are the most common cause of head injuries so road traffic safety measures ought to be strictly enforced. Most of the CT scan done during head injuries were normal so CT guidelines for ordering should be implemented to scale back extra patient irradiation, unnecessary waste of resources and a further burden on the radiology department. Keywords: Head Injury, Computed Tomography (CT), Road Traffic Accidents (RTA), Skull Fractures, Epidural Hematoma.

Computed Tomography Scan Findings in Various Modes of Head Injury, using Ge Optima 128 Slice CT Scanner

Background: Head injury is a global health problem that can cause disability and may result in death. CT scan detects and precisely localizes the skull fractures, epidural/subdural/subarachnoid hemorrhages, brain contusions and cerebral edema etc. CT has proven to be a valuable tool in the early diagnosis and prompt management of head trauma patients. Methods: A descriptive cross-sectional study, including 380 patients, presented to the radiology department of Hayatabad medical complex witha history of head trauma for computed tomography examination, from October 2019 to October 2020. The nature of the brain and skull lesions was analyzed in our study and the frequency of various findings was recorded. Results: Among 380 patients, the majority were males (248) making the male to female ratio to be around 2:1. The most prevalent finding was skull fractures (23.4%) followed by cerebral contusions (17.1%). Among extra-axial brain hemorrhages, extradural hematoma (15.2%) was observed more than subdural hematoma (6.8%) while only 3.4% presented with subarachnoid hemorrhages which also included intraventricular hemorrhages. Practical Implication: As road traffic accidents are the most common cause of head injuries so road traffic safety measures ought to be strictly enforced. Most of the CT scan done during head injuries were normal so CT guidelines for ordering should be implemented to scale back extra patient irradiation, unnecessary waste of resources Conclusion: Our study concluded that younger populations and males are more prone to head injury and road traffic accident is the most common mode of head trauma. So, ensuring proper traffic rules along with educating the more prone population will significantly reduce the incidence of serious head injuries. Keywords: Head Injury, Computed Tomography (CT), Road Traffic Accidents (RTA), Skull Fractures, Epidural Hematoma.

McS-Net: Multi-class Siamese network for severity of COVID-19 infection classification from lung CT scan slices

Worldwide COVID-19 is a highly infectious and rapidly spreading disease in almost all age groups. The Computed Tomography (CT) scans of lungs are found to be accurate for the timely diagnosis of COVID-19 infection. In the proposed work, a deep learning-based P-shot N-ways Siamese network along with prototypical nearest neighbor classifiers is implemented for the classification of COVID-19 infection from lung CT scan slices. For this, a Siamese network with an identical sub-network (weight sharing) is used for image classification with a limited dataset for each class. The feature vectors are obtained from the pre-trained sub-networks having weight sharing. The performance of the proposed methodology is evaluated on the benchmark MosMed dataset having categories zero (healthy control) and numerous COVID-19 infections. The proposed methodology is evaluated on (a) chest CT scans provided by medical hospitals in Moscow, Russia for 1110 patients, and (b) case study of low-dose CT scans of 42 patients provided by Avtaran healthcare in India. The deep learning-based Siamese network (15-shot 5-ways) obtained an accuracy of 98.07%, the sensitivity of 95.66%, specificity of 98.83%, and F1-score of 95.10%. The proposed work outperforms the COVID-19 infection severity classification with limited scans availability for numerous infection categories.

After Total Ankle Arthroplasty, When Does Bone Perfusion and Metabolic Activity at the Bone-Implant Interface Normalize? A PET/CT Study

Category: Ankle Arthritis Introduction/Purpose: Radionuclide bone scintigraphy in combination with computed tomography (CT) has been used to evaluate painful total hip and knee arthroplasties, and has also been used in the evaluation of the painful total ankle arthroplasty (TAA). Increased tracer uptake around implants may indicate loosening, but uptake characteristics of bone-seeking radiopharmaceuticals in asymptomatic total ankle patients have not been clarified. While findings of increased metabolic activity may prompt surgical intervention, there has been no work performed to define when postoperatively periprosthetic activity normalizes, if at all. In this study, we plan to establish normative data on 18F sodium fluoride (18F-NaF) positron emission tomography/CT (PET/CT) uptake ratios around TAA implants at various time intervals after surgery in asymptomatic TAA patients. Methods: The majority of the arthroplasty literature has investigated use of SPECT/CT performed with 99mTc-labeled bisphosphonates. However, data suggest that 18F-NaF PET/CT may be superior for this indication, with more favorable pharmacokinetics and similar sensitivity to detect aseptic loosening. In the present study, asymptomatic patients who underwent TAA with a modern fixed-bearing TAA prosthesis (either the Wright Infinity Adaptis or Exactech Vantage prosthesis) for posttraumatic arthritis were eligible for inclusion. Patients with ipsilateral hindfoot fusion and with any periprosthetic lucencies or cysts were excluded. Patients were enrolled at one of four time intervals following TAA: 6, 12, 18, or 24 months. Standard uptake values were measured at the bone-implant interface for the tibial and talar components on static PET, in regions of interest defined on axial CT scan slices. Periprosthetic bone blood flow (K1) and bone turnover (flux) were assessed at each time interval in each periprosthetic region using dynamic PET. Results: Sixteen asymptomatic patients underwent PET/CT: 4 patients at 6 months postoperatively, 6 at 12 months, and 6 at 24 months. We are currently still in data collection and at this time only 2 patients at 18 months have completed the scan, therefore their data were excluded. The average age was 65 years (range, 55 to 80) and 6 patients were female (38%), with individual patient data shown in the Table. Talar K1 and flux both appeared to increase from 6 to 12 months, and decrease between 12 and 24 months, although there was no statistically significant difference between timepoints. Overall tibial K1 and flux appeared to decrease slightly from 6 to 12 months, and stayed relatively stable between 12 and 24 months, again with no significant difference between timepoints (Figure). Conclusion: There is currently no normative data to help guide interpretation of radionuclide bone scintigraphy for the painful TAA. The present study utilizing 18F-NaF PET/CT scans demonstrates that even in asymptomatic patients, periprosthetic bone blood flow and bone turnover remain elevated up to 24 months following modern fixed-bearing TAA. Not only do these values remain elevated at 24 months, but we found that there does not appear to be any significant decrease in either measurement over time from 6 to 24 months postoperatively. Our findings suggest that radionuclide bone scintigraphy should be cautiously interpreted when performed within 2 years of TAA.

Method of evaluating cement-to-formation bond strength with computed tomography image analysis

Invention of new cements for effective zonal isolation requires bond strength evaluation of the cement to formation. We present a method to evaluate the cement-to-formation bond strength based on the flow of cement through a formation using image analysis. Most researchers perform image analysis on a single slice. This is the first known nondestructive method devised using a quantitative analysis on a sequence of slices from X-ray computed tomography (CT) scans. The number of CT scan slices in which the porosity changes is used to evaluate the bond strength of cement. Our findings demonstrate that the cement-to-formation bond strength is affected by permeability of a formation and viscosity of cement if other physical (sample preparation and measuring conditions) and chemical (cement additives) variables remain constant.

Impact of ROI Size on the Accuracy of Noise Measurement in CT on Computational and ACR Phantoms.

Background: The effect of region of interest (ROI) size variation on producing accurate noise levels is not yet studied.Objective: This study aimed to evaluate the influence of ROI sizes on the accuracy of noise measurement in computed tomography (CT) by using images of a computational and American College of Radiology (ACR) phantoms.Material and Methods: In this experimental study, two phantoms were used, including computational and ACR phantoms. A computational phantom was developed by using Matlab R215a software (Mathworks Inc., Natick, MA Natick, MA) with a homogeneously +100 Hounsfield Unit (HU) value and an added-Gaussian noise with various levels of 5, 10, 25, 50, 75, and 100 HU. The ACR phantom was scanned with a Philips MX-16 slice CT scanner in different slice thicknesses of 1.5, 3, 5, and 7 mm to obtain noise variation. Noise measurement was conducted at the center of the phantom images and four locations close to the edge of the phantom images using different ROI sizes from 3 × 3 to 41 × 41 pixels, with an increased size of 2 × 2 pixels.Results: The use of a minimum ROI size of 21 × 21 pixels shows noise in the range of ± 5% ground truth noise. The measured noise increases above the ± 5% range if the used ROI is smaller than 21 × 21 pixels.Conclusion: A minimum acceptable ROI size is required to maintain the accuracy of noise measurement with a size of 21 × 21 pixels.

The impact of ASiR-V on abdominal CT radiation dose and image quality – A phantom study

IntroductionTo investigate how ASiR-V and kVp changes in Computed tomography (CT) affect radiation dose and image quality, when using automatic tube current modulation (ATCM) for different sized phantoms. MethodsA liver-phantom with two different liver inserts (QRM, Moehrendorf, Germany), with extension rings, representing fat, were additionally applied to the phantom to simulate patients of different sizes (small: 30cm diameter, medium: 35cm and large: 40cm). Abdominal scans were performed on a 256 slice CT scanner (GE Healthcare, Milwaukee, WI, USA), with consistent pitch (0.992), rotation time (0.5s), slice thickness (0.625mm) and collimation (80mm), while other parameters were varied (kVp: 80/100/120/140; Noise Index: 13/22; mA interval 80-720, ASiR-V: 30/60/100%). CTDI and DLP was recorded for each scan and image quality was assessed using objective metrics in predefined anatomic areas (HU and noise). Radiation dose and image quality metrics were compared between protocols. ResultsCTDI decreased by 80% from ASIR-V 30% to ASiR-V 100% for prescribed NI 13, and by 79% for the prescribed NI of 22. For 100% ASiR-V and a prescribed NI of 22 the CTDI remained the same regardless of phantom size for the different kVp settings. Pairwise comparison revealed significant differences in CTDI (p < 0.0001) for all combinations of prescribed NI and ASIR-V levels, except the difference between ASIR-V levels of 30 and 60%, with a prescribed NI of 13 (p = 0.124).When data from the three phantom sizes were combined, increasing ASIR-V from 30-100%, resulted in noise decreases of 22% for NI of 13 and by 8% for NI of 22. Notably, image quality in the low contrast area of the liver insert was impaired when the large phantom was scanned with 100% ASiR-V and either 80/100kVp (NI 22), because of the large reduction in tube current applied (down to 80 mA). ConclusionSubstantial radiation dose reductions (up to 80%) resulted from increasing ASiR-V levels. However, image quality deteriorates when 100% ASiR-V is applied due to low applied tube current by the ATCM.

Effective radiation dose and radiogenic cancer risk during contrast enhanced abdominal computed tomography examinations

Pediatrics and children have higher radiosensitivity to ionizing radiation and radiogenic risks than adults due to their rapidly dividing tissues. This study explores the infant and children radiation doses during computed tomography (CT) abdomen and estimates the cancer risk from the procedure. In total, 87 were examined for CT enhanced abdominal examination. The abdominal CT scan with contrast was performed using a 128-slice multi slice CT (MSCT) scan. The mean, standard deviation, and range of patients' age (years) are 13 ± 4.5 (2–17). The mean and range of the air kerma length product (PKL(mGy.cm)) and volume CT air kerma index (Cvol (mGy)) were 1740 (157.8–8440.3) (mGy.cm) and 9.8 (2.09–45.77) (mGy) per CT abdomen procedure, respectively. The mean and range of the effective dose (mSv) per procedure are 34 (3.14–176.8). The average radiogenic risk per CT procedure is one cancer incidence per 250 CT enhanced abdomen procedures. The mean and range of total irradiation even are 4.0 (2.0–8.0) times per procedure. The results of this study showed that child risk is high compared to other CT examinations. Therefore, patients’ dose optimization and proper establishment of a diagnostic reference level (DRL) are necessary to preventing avoidable radiation risks.