scholarly journals A Comparison of the Distortion in the Same Field MRI and MR-Linac System With a 3D Printed Phantom

2021 ◽  
Vol 11 ◽  
Author(s):  
Xuechun Liu ◽  
Zhenjiang Li ◽  
Yi Rong ◽  
Minsong Cao ◽  
Hongyu Li ◽  
...  

PurposeA 3D printed geometric phantom was developed that can be scanned with computed tomography (CT) and magnetic resonance imaging (MRI) to measure the geometric distortion and determine the relevant dose changes.Materials and MethodsA self-designed 3D printed photosensitive resin phantom was used, which adopts grid-like structures and has 822 1 cm2 squares. The scanning plan was delivered by three MRI scanners: the Elekta Unity MR-Linac 1.5T, GE Signa HDe 1.5T, and GE Discovery-sim 750 3.0T. The geometric distortion comparison was concentrated on two 1.5T MRI systems, whereas the 3.0T MRI was used as a supplemental experiment. The most central transverse images in each dataset were selected to demonstrate the plane distortion. Some mark points were selected to analyze the distortion in the 3D direction based on the plane geometric distortion. A treatment plan was created with the off-line Monaco system.ResultsThe distortion increases gradually from the center to the outside. The distortion range is 0.79 ± 0.40 mm for the Unity, 1.31 ± 0.56 mm for the GE Signa HDe, and 2.82 ± 1.48 mm for the GE Discovery-sim 750. Additionally, the geometric distortion slightly affects the actual planning dose of the radiotherapy.ConclusionGeometric distortion increases gradually from the center to the outside. The distortion values of the Unity were smaller than those of the GE Signa HDe, and the Unity has the smallest geometric distortion. Finally, the Unity’s dose variation best matched with the standard treatment plan.

2020 ◽  
Vol 13 (4) ◽  
pp. 389-406
Author(s):  
Jiten Chaudhary ◽  
Rajneesh Rani ◽  
Aman Kamboj

PurposeBrain tumor is one of the most dangerous and life-threatening disease. In order to decide the type of tumor, devising a treatment plan and estimating the overall survival time of the patient, accurate segmentation of tumor region from images is extremely important. The process of manual segmentation is very time-consuming and prone to errors; therefore, this paper aims to provide a deep learning based method, that automatically segment the tumor region from MR images.Design/methodology/approachIn this paper, the authors propose a deep neural network for automatic brain tumor (Glioma) segmentation. Intensity normalization and data augmentation have been incorporated as pre-processing steps for the images. The proposed model is trained on multichannel magnetic resonance imaging (MRI) images. The model outputs high-resolution segmentations of brain tumor regions in the input images.FindingsThe proposed model is evaluated on benchmark BRATS 2013 dataset. To evaluate the performance, the authors have used Dice score, sensitivity and positive predictive value (PPV). The superior performance of the proposed model is validated by training very popular UNet model in the similar conditions. The results indicate that proposed model has obtained promising results and is effective for segmentation of Glioma regions in MRI at a clinical level.Practical implicationsThe model can be used by doctors to identify the exact location of the tumorous region.Originality/valueThe proposed model is an improvement to the UNet model. The model has fewer layers and a smaller number of parameters in comparison to the UNet model. This helps the network to train over databases with fewer images and gives superior results. Moreover, the information of bottleneck feature learned by the network has been fused with skip connection path to enrich the feature map.


2019 ◽  
Vol 10 (1) ◽  
pp. 175
Author(s):  
Alex J. Deakyne ◽  
Tinen L. Iles ◽  
Alexander R. Mattson ◽  
Paul A. Iaizzo

Data relative to anatomical measurements, spatial relationships, and device–tissue interaction are invaluable to medical device designers. However, obtaining these datasets from a wide range of anatomical specimens can be difficult and time consuming, forcing designers to make decisions on the requisite shapes and sizes of a device from a restricted number of specimens. The Visible Heart® Laboratories have a unique library of over 500 perfusion-fixed human cardiac specimens from organ donors whose hearts (and or lungs) were not deemed viable for transplantation. These hearts encompass a wide variety of pathologies, patient demographics, surgical repairs, and/or interventional procedures. Further, these specimens are an important resource for anatomical study, and their utility may be augmented via generation of 3D computational anatomical models, i.e., from obtained post-fixation magnetic resonance imaging (MRI) scans. In order to optimize device designs and procedural developments, computer generated models of medical devices and delivery tools can be computationally positioned within any of the generated anatomical models. The resulting co-registered 3D models can be 3D printed and analyzed to better understand relative interfaces between a specific device and cardiac tissues within a large number of diverse cardiac specimens that would be otherwise unattainable.


Author(s):  
Andrew D. Norden ◽  
Whitney B. Pope ◽  
Susan M. Chang

Overview: Magnetic resonance imaging (MRI) is the most useful imaging tool in the evaluation of patients with brain tumors. Most information is supplied by standard anatomic images that were developed in the 1980s and 1990s. More recently, functional imaging including diffusion and perfusion MRI has been investigated as a way to generate predictive and prognostic biomarkers for high-grade glioma evaluation, but additional research is needed to establish the added benefits of these indices to standard MRI. Response critieria for high-grade gliomas have recently been updated by the Response Assessment in Neuro-Oncology (RANO) working group. The new criteria account for nonenhancing tumor in addition to the contrast-enhancing abnormalities on which older criteria relied. This issue has recently come to the fore with the introduction of the antiangiogenic agent bevacizumab into standard treatment for recurrent glioblastoma. Because of its potent antipermeability effect, contrast enhancement is markedly reduced in patients who receive bevacizumab. The RANO criteria also address the phenomenon of pseudoprogression, in which there may be transient MRI worsening of a glioblastoma following concurrent radiotherapy and temozolomide.


2018 ◽  
Vol 1 (90) ◽  
pp. 33-40
Author(s):  
Dzh. Dzhendov ◽  
Iv. Katreva ◽  
Ts. Dikova

Purpose: of the present paper is to develop prosthetic treatment protocol for fixed partial dentures made of 3D printed cast patterns. Design/methodology/approach: The clinical and laboratory protocols for manufacturing of fixed prosthetic constructions upon 3D cast patterns are developed on the basis of the literature review and our previous experimental investigations. Comparison between the conventional technique and innovative approach is made. Findings: The terms "semi-digital treatment plan" and "fully digital treatment plan" are defined according to the way of obtaining data for the virtual 3D model and the production method of the fixed prostheses. A classification of treatment protocols with non-removable partial dentures produced by additive technology is developed. Protocols for "semi" and "fully" digitized treatment plans with fixed partial dentures made by casting with 3D printed models are created. Research limitations/implications: Implementation of the fully digitized protocol for manufacturing of fixed prosthetic constructions via 3D printed prototypes requires specific equipment in the dental office and dental technician laboratory – intraoral scanner and CAD/ CAM system with 3D printing machine. Practical implications: Establishing of systematic clinical and laboratory protocols helps dental specialists to implement the innovative working approach in their practice with no risk of neglecting or omitting of some important procedures which increases the quality and long lasting effect of the dental constructions. Originality/value: Following the developed protocols reduces the role of the subjective factor in production technology of fixed prosthetic constructions while saving labour and time.


2020 ◽  
Vol 3 (3) ◽  
pp. 122-127
Author(s):  
Christa Levina Daniswara ◽  
Rumuat Semuel Wullul Manangka

Breast cancer is the most common cancer in women and is the most significant cause of morbidity and mortality in women cancer patients. Increased awareness of people followed by periodic screening, appropriate supporting examinations, and imaging modalities according to the patient's condition could improve prognosis. We report a case report of a 55-year-old woman with a complaint of a lump in the right breast. Ultrasound examination and mammography showed a single solid lesion in the superior quadrant of the right breast corresponding to Breast Imaging-Reporting and Data System (BI-RADS) 4c. Magnetic Resonance Imaging (MRI) examination revealed a single lesion with enhancement curve type 1 according to bi-rads 4b. Results of the biopsy were grade 2 breast carcinoma without any lymph node metastases. The use of a single modality cannot be used as a benchmark in determining the best diagnosis and therapy. The kinetic feature/enhancement curve of Dynamic Contrast-Enhanced MRI (DCE-MRI) cannot be used as the main guide for determining the diagnosis. The morphology of the lesion either from ultrasound, mammography, or MRI should also be considered in determining the diagnosis and treatment plan


F1000Research ◽  
2017 ◽  
Vol 6 ◽  
pp. 1603
Author(s):  
Jagannadha Avasarala ◽  
Todd Pietila

Conventional magnetic resonance imaging (MRI) studies depict disease of the human brain in 2D but the reconstruction of a patient’s brain stricken with multiple sclerosis (MS) in 3D using 2D images has not been attempted. Using 3D reconstruction algorithms, we built a 3D printed patient-specific brain model to scale. It is a first of its kind model that depicts the total white matter lesion (WML) load using T2 FLAIR images in an MS patient. The patient images in Digital Imaging and Communications in Medicine (DICOM) format were imported into Mimics inPrint 2.0 (Materialise NV, Leuven, Belgium) a dedicated medical image processing software for the purposes of image segmentation and 3D modeling.  The imported axial images were automatically formatted to display coronal and sagittal slices within the software. The imaging study was then segmented into regions and surface rendered to achieve 3D virtual printable files of the desired structures of interest. Rendering brain tumor(s) in 3D has been attempted with the specific intent of extending the options available to a surgeon but no study to our knowledge has attempted to quantify brain disease in MS that has, for all practical purposes, no surgical options.


F1000Research ◽  
2018 ◽  
Vol 6 ◽  
pp. 1603
Author(s):  
Jagannadha Avasarala ◽  
Todd Pietila

Conventional magnetic resonance imaging (MRI) studies depict disease of the human brain in 2D but the reconstruction of a patient’s brain stricken with multiple sclerosis (MS) in 3D using 2D images has not been attempted.  Using 3D reconstruction algorithms, we built a 3D printed patient-specific brain model to scale. It is a first of its kind model that depicts the total white matter lesion (WML) load using T2 FLAIR images in an MS patient. The patient’s images in Digital Imaging and Communications in Medicine (DICOM) format were imported into Mimics inPrint 2.0 (Materialise NV, Leuven, Belgium) a dedicated medical image processing software designed for the purposes of image segmentation and 3D modeling.  The imported axial images were automatically formatted to display coronal and sagittal slices within the software. The imaging data were then segmented into regions and surface rendering was done to achieve 3D virtual printable files of the desired structures of interest. Rendering brain tumor(s) in 3D has been attempted with the specific intent of extending the options available to a surgeon but no study to our knowledge has attempted to quantify brain disease in MS that has, for all practical purposes, no surgical options. The purpose of our study was to demonstrate that 3D depiction of chronic neurological diseases is possible in a printable model while serving a fundamental need for patient education. Medical teaching is moored in 2D graphics and it is time to evolve into 3D models that can be life-like and deliver instant impact.


2021 ◽  
Vol 6 (6) ◽  
pp. 472-486
Author(s):  
Markus S. Hanke ◽  
Till D. Lerch ◽  
Florian Schmaranzer ◽  
Malin K. Meier ◽  
Simon D. Steppacher ◽  
...  

Preoperative evaluation of the pathomorphology is crucial for surgical planning, including radiographs as the basic modality and magnetic resonance imaging (MRI) and case-based additional imaging (e.g. 3D-CT, abduction views). Hip arthroscopy (HAS) has undergone tremendous technical advances, an immense increase in use and the indications are getting wider. The most common indications for revision arthroscopy are labral tears and residual femoroacetabular impingement (FAI). Treatment of borderline developmental dysplastic hip is currently a subject of controversy. It is paramount to understand the underlining problem of the individual hip and distinguish instability (dysplasia) from FAI, as the appropriate treatment for unstable hips is periacetabular osteotomy (PAO) and for FAI arthroscopic impingement surgery. PAO with a concomitant cam resection is associated with a higher survival rate compared to PAO alone for the treatment of hip dysplasia. Further, the challenge for the surgeon is the balance between over- and undercorrection. Femoral torsion abnormalities should be evaluated and evaluation of femoral rotational osteotomy for these patients should be incorporated to the treatment plan. Cite this article: EFORT Open Rev 2021;6:472-486. DOI: 10.1302/2058-5241.6.210019


2013 ◽  
Vol 32 (04) ◽  
pp. 265-267
Author(s):  
José Alberto Gonçalves da Silva ◽  
Adailton Arcanjo dos Santos Junior

AbstractThe lumbar pseudomeningocele (PSM) is an uncommon condition, mainly, after a lumbar blunt trauma. The authors present a rare case of PSM following a lumbar blunt trauma which did not show any abnormalities in the magnetic resonance imaging (MRI) of the lumbar region. Firstly, the patient underwent to conservative treatment that fail and then it was performed a surgical approach of the lumbar area, however, the lumbar fluid collection appeared again and a lumboperitoneal shunt (LPS) was then performed with complete successful. One year and half afterwards the LPS the patient continues asymptomatic. The standard treatment of this condition remains uncertain, but the conservative treatment followed by LPS is a good option and can be done in several cases.


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