Ali Ursani - Academia.edu (original) (raw)

Papers by Ali Ursani

3D printing in medicine, Feb 5, 2020

An anthropomorphic phantom is a radiologically accurate, tissue realistic model of the human body... more An anthropomorphic phantom is a radiologically accurate, tissue realistic model of the human body that can be used for research into innovative imaging and interventional techniques, education simulation and calibration of medical imaging equipment. Currently available CT phantoms are appropriate tools for calibration of medical imaging equipment but have major disadvantages for research and educational simulation. They are expensive, lacking the realistic appearance and characteristics of anatomical organs when visualized during X-ray based image scanning. In addition, CT phantoms are not modular hence users are not able to remove specific organs from inside the phantom for research or training purposes. 3D printing technology has evolved and can be used to print anatomically accurate abdominal organs for a modular anthropomorphic mannequin to address limitations of existing phantoms. In this study, CT images from a clinical patient were used to 3D print the following organ shells: liver, kidneys, spleen, and large and small intestines. In addition, fatty tissue was made using modelling beeswax and musculature was modeled using liquid urethane rubber to match the radiological density of real tissue in CT Hounsfield Units at 120kVp. Similarly, all 3D printed organ shells were filled with an agar-based solution to mimic the radiological density of real tissue in CT Hounsfield Units at 120kVp. The mannequin has scope for applications in various aspects of medical imaging and education, allowing us to address key areas of clinical importance without the need for scanning patients.

Physics in Medicine and Biology, Feb 10, 2010

Increased pixel noise and streak artifact reduce CT image quality and limit the potential for rad... more Increased pixel noise and streak artifact reduce CT image quality and limit the potential for radiation dose reduction during CT of the thoracic inlet. We propose to quantify the pixel noise of mediastinal structures in the thoracic inlet, during low-dose (LDCT) and ultralow-dose (uLDCT) thoracic CT, and assess the utility of new software (quantum denoising system and BOOST3D) in addressing these limitations. Twelve patients had LDCT (120 kV, 25 mAs) and uLDCT (120 kV, 10 mAs) images reconstructed initially using standard mediastinal and lung filters followed by the quantum denoising system (QDS) to reduce pixel noise and BOOST3D (B3D) software to correct photon starvation noise as follows: group 1 no QDS, no B3D; group 2 B3D alone; group 3 QDS alone and group 4 both QDS and B3D. Nine regions of interest (ROIs) were replicated on mediastinal anatomy in the thoracic inlet, for each patient resulting in 3456 data points to calculate pixel noise and attenuation. QDS reduced pixel noise by 18.4% (lung images) and 15.8% (mediastinal images) at 25 mAs. B3D reduced pixel noise by approximately 8% in the posterior thorax and in combination there was a 35.5% reduction in effective radiation dose (E) for LDCT (1.63-1.05 mSv) in lung images and 32.2% (1.55-1.05 mSv) in mediastinal images. The same combination produced 20.7% reduction (0.53-0.42 mSv) in E for uLDCT, for lung images and 17.3% (0.51-0.42) for mediastinal images. This quantitative analysis of image quality confirms the utility of dedicated processing software in targeting image noise and streak artifact in thoracic LDCT and uLDCT images taken in the thoracic inlet. This processing software potentiates substantial reductions in radiation dose during thoracic LDCT and uLDCT.

Springer eBooks, 2015

This project presents development of a realistic dynamic anthropomorphic heart phantom (DHAP), wh... more This project presents development of a realistic dynamic anthropomorphic heart phantom (DHAP), which can mimic any heart rhythm of the patient while waiting in the holding area. The dynamic heart phantom driven in real time from the patient’s ECG or built in simulator; then can be scanned in the CT to establish the best gating protocol suitable to current heart rhythms of the patient. Once the protocol is established the patient can be scanned only applying single gating technique; hence significant radiation dose can be reduced for these patients.

Poster: "ECR 2017 / C-2929 / Optimisation of CT coronary angiography for coronary vessel wal... more Poster: "ECR 2017 / C-2929 / Optimisation of CT coronary angiography for coronary vessel wall visualisation and detection of non-calcified plaque" by: "H. Kashani, G. Wright, A. Ursani, G. Liu, N. Paul; Toronto, ON/CA"

Poster: "ECR 2012 / C-1859 / Effect of patient habitus on organ radiation dose and image qua... more Poster: "ECR 2012 / C-1859 / Effect of patient habitus on organ radiation dose and image quality for chest computed tomography: a phantom study" by: "D. Odedra1, H. Kashani1, H. Mehrez2, A. Ursani1, J. Blobel3, N. Paul1; 1Toronto, ON/CA, 2Markham, ON/CA, 3Neuss/DE"

American Journal of Roentgenology, Dec 1, 2011

C a r d io p u lm o n a r y I m ag i ng • O r ig i n a l R e s e a rc h

American Journal of Roentgenology, Feb 1, 2011

M e d ic a l Phys ic s a n d I n fo r m a t ic s • O r ig i n a l R e s e a rc h WEB This is a We... more M e d ic a l Phys ic s a n d I n fo r m a t ic s • O r ig i n a l R e s e a rc h WEB This is a Web exclusive article.

Journal of the American College of Cardiology, Oct 1, 2015

CardioVascular and Interventional Radiology

Any information contained in this pdf file is automatically generated from digital material submi... more Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expen...

Although the high quality of medical images is strictly controlled during acquisition, it is ofte... more Although the high quality of medical images is strictly controlled during acquisition, it is often not adequately maintained during image review. This is due to the lack of a published process and information on optimal monitor settings for medical image viewing. Other complications include large differences between various types, applications, and vendors, and scarce literature describing monitor quality control protocols. Guidelines and recommendations also vary between countries and are sometimes conflicting . The University Health Network (UHN) is comprised of the Toronto General, Toronto Western, and Princess Margaret Hospitals. The UHN Medical Imaging Department also manages medical imaging at the Mount Sinai Hospital (MSH). Approximately 450 computers at UHN and 200 computers at Mount Sinai Hospital are able to review medical images through the PACS (Picture Archiving and Communication System) using the eFilm Workstation application. The majority of PACS clinical review works...

Three dimensional (3D) printing is an exciting tool in patient centered precision medicine. Usefu... more Three dimensional (3D) printing is an exciting tool in patient centered precision medicine. Useful applications for 3D printing tools have been developed in medical education and for surgical planning. However, 3D printing is not commonplace in medical imaging (MI) departments. A successful 3D printing program in MI requires the close collaboration of a multi- disciplinary team that includes the radiologist, technologist, medical physicist and the biomedical engineer. This case study successfully demonstrates multi-disciplinary collaboration in designing and constructing an abdominal phantom with realistic radiological and anatomical structural properties utilizing 3D printing methods and appropriate materials.

Bioprinting, 2020

There is a growing interest in using Computed Tomography (CT) and Hounsfield Unit (HU) measuremen... more There is a growing interest in using Computed Tomography (CT) and Hounsfield Unit (HU) measurements in identifying and assessing non-calcified plaque; however, the complex geometry of the coronary arteries poses a challenge in achieving good image quality, which is crucial in providing patients with an accurate diagnosis. Minimizing artifacts associated with cardiac motion is also an important step in improving CT diagnostic accuracy of Coronary Artery Disease. Existing arterial phantoms are commonly straight, short tubular sections that are often rigid, and do not represent the geometry of the entire arterial network, with which image quality and Hounsfield Unit measurements vary and are dependent on. In this study, the process of manufacturing a plaque phantom with physiologically accurate geometry of the coronary arteries is demonstrated. A computer model is obtained by segmenting CTCA images, and several flexible commercially available materials are used to 3D print the model. The static and dynamic mechanical properties of the 3D printing materials are investigated under physiologically relevant loading and the CT numbers of contrast-enhanced tubular samples with 50%, 75%, and 90% concentric stenosis are characterized and compared with ranges for lipid-rich and fibrous plaque. The proposed plaque phantom design offers the possibility of investigating the effect of non-calcified plaque geometry and arterial motion on various parameters in CT optimization studies.

The British Journal of Radiology, 2019

Objective:Evaluation of coronary CT image blur using multi segment reconstruction algorithm.Metho... more Objective:Evaluation of coronary CT image blur using multi segment reconstruction algorithm.Methods:Cardiac motion was simulated in a Catphan. CT coronary angiography was performed using 320 × 0.5 mm detector array and 275 ms gantry rotation. 1, 2 and 3 segment reconstruction algorithm, three heart rates (60, 80 and 100bpm), two peak displacements (4, 8 mm) and three cardiac phases (55, 35, 75%) were used. Wilcoxon test compared image blur from the different reconstruction algorithms.Results:Image blur for 1, 2 and 3 segments in: 60 bpm, 75% R–R interval and 8 mm peak displacement: 0.714, 0.588, 0.571 mm (1.18, 0.6, 0.4 mm displacement) 80 bpm, 35% R–R interval and 8 mm peak displacement: 0.869, 0.606, 0.606 mm (1.57, 0.79,0.52 mm displacement) 100 bpm, 35% R–R interval and 4 mm peak displacement: 0.645, 0.588, 0.571 mm (0.98, 0.49, 0.33 mm displacement). The median image blur overall for 1 and 2 segments was 0.714 mm and 0.588 mm respectively (p < 0.0001).Conclusion:Two-segment ...

Biomedical Physics & Engineering Express, 2019

Journal of Medical Imaging and Radiation Sciences, 2018

Purpose: Lung cancer is a leading cause of mortality worldwide, with poorer outcomes when compare... more Purpose: Lung cancer is a leading cause of mortality worldwide, with poorer outcomes when compared to other common cancers. Diagnostic capacity is frequently identified as a barrier to early diagnosis. Evidence demonstrates that advanced practitioner reporting radiographers can provide effective, efficient and patient focused care. The aim of this study was to explore novel ways advanced practitioner radiographers can support lung cancer pathways. Methods: A two stage project was developed to create additional diagnostic capacity in a sustainable way. Immediate reporting of chest X-rays (CXRs) from general practice was piloted at a single clinical site. Time to diagnosis of lung cancer and intermediate points (reporting time, time to CT, time to MDT) was compared with routine reporting. A novel hub and spoke model to train a pan-London cohort of 15 CXR reporting radiographers was implemented, using established centres to support other departments. Trainee and departmental satisfaction was assessed. Results: Feasibility of radiographer immediate CXR reporting was demonstrated; over 3 months 522 of 1,687 CXRs received an immediate report. A significant reduction was found in time from abnormal CXR to CT (0.9 days vs. 6.5 days; p<0.0001) and discussion at MDT (4.1 days vs. 10.6 days; p<0.00101) with immediate CXR reporting. Significant efficiencies were realised with centralised tutorial support with 48 hours of expert time used to support the trainees compared to traditional workplace support (348 hours). Both trainees and managers rated the programme highly, with diverse case-mix, range of tutors and peer support strong benefits. Logistical issues, such as travel and timing of tutorials require improvement for subsequent cohorts. Conclusions: Advanced practitioner radiographers can provide additional diagnostic capacity, streamlining the lung cancer pathway in an efficient way.

IFMBE Proceedings, 2015

Journal of Digital Imaging, 2005

Image quality assurance has traditionally been a high priority in medical imaging departments. Re... more Image quality assurance has traditionally been a high priority in medical imaging departments. Recently, it has often been neglected with the transition from hard copy (film) to soft copy (computer) display systems, which could potentially result in difficulty in reading images or even misdiagnosis. This transition therefore requires careful management such that comparable image quality is achieved at a minimum. It is particularly difficult to maintain appropriate image quality in the clinical settings outside of medical imaging departments because of the volume of display systems and the financial restraints that prohibit the widespread use of dedicated computers and high-quality monitors. In this study, a protocol to test and calibrate display systems was developed and validated by using an inexpensive calibration tool. Using this protocol, monitors were identified in a hospital in which image quality was found to be inadequate for medical image viewing. It was also found that most monitors could achieve a substantial increase in image quality after calibration. For example, the 0 and 5% luminance difference was discernable on 30% of the piloted display systems before calibration, but it was discernable on 100% post calibration. In addition, about 50% of the piloted display systems did not have the maximum luminance (white level) suitably set, and 35% of them did not have the minimum luminance (dark level) suitably set. The results indicate that medical display systems must be carefully selected and strictly monitored, maintained, and calibrated to ensure adequate image quality.