T2*-weighted MRI produces viable fetal “Black-Bone” contrast with significant benefits when compared to current sequences

2021 ◽  
pp. 20200940
Author(s):  
Alex Francis Goodall ◽  
Alex Barrett ◽  
Elspeth Whitby ◽  
Andrew Fry
Keyword(s):  
Soft Tissue ◽  
Image Quality ◽  
Fetal Mri ◽  
Ionising Radiation ◽  
Point Scale ◽  
Motion Artefacts ◽  
Good Image Quality ◽  
Soft Tissue Contrast ◽  
Tissue Contrast ◽  
Almost All

Objectives: Fetal “black bone” MRI could be useful in the diagnosis of various skeletal conditions during pregnancy without exposure to ionising radiation. Previously suggested Susceptibility-Weighted Imaging (SWI) is not available in the suggested form on all scanners leading to long imaging times that are susceptible to motion artefacts. We aimed to assess if an optimised T2*-weighted GRE sequence can provide viable “black bone” contrast and compared it to other sequences in the literature. Methods: A retrospective study was conducted on 17 patients who underwent fetal MRI. Patients were imaged with an optimised T2*-weighted GRE sequence, as well as at least one other “black-bone” sequence. Image quality was scored by four blinded observers on a five-point scale. Results: The T2*-weighted GRE sequence offered adequate to excellent image quality in 63% of cases and scored consistently higher than the three other comparison sequences when comparing images from the same patient. Image quality was found to be dependent on gestational age with good image quality achieved on almost all patients after 26 weeks. Conclusions: T2*-weighted GRE imaging can provide adequate fetal “black bone” contrast and performs at least as well as other sequences in the literature due to good bone to soft tissue contrast and minimal motion artefacts. Advances in knowledge: T2*-weighted fetal “black-bone” imaging can provide excellent bone to soft tissue contrast without using ionising radiation. It is as good as other “black bone” sequences and may be simpler and more widely implemented, with less motion artefacts.

Soft-tissue contrast resolution within the head of human cadaver by means of flat-detector-based cone-beam CT

2004 ◽  
Author(s):  
Jens Wiegert ◽  
Matthias Bertram ◽  
Dirk Schaefer ◽  
Norbert Conrads ◽  
Niels Noordhoek ◽  
...  
Keyword(s):  
Soft Tissue ◽  
Cone Beam Ct ◽  
Cone Beam ◽  
Human Cadaver ◽  
Flat Detector ◽  
Contrast Resolution ◽  
Soft Tissue Contrast ◽  
Tissue Contrast

scholarly journals New Updates of the Imaging Role in Diagnosis, Staging, and Response Treatment of Malignant Pleural Mesothelioma

Cancers ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 4377
Author(s):  
Chiara Romei ◽  
Salvatore Claudio Fanni ◽  
Federica Volpi ◽  
Alessio Milazzo ◽  
Caterina Aida D’Amore ◽  
...  
Keyword(s):  
Soft Tissue ◽  
Malignant Pleural Mesothelioma ◽  
Therapy Response ◽  
Staging System ◽  
Clinical Settings ◽  
Pleural Mesothelioma ◽  
Soft Tissue Contrast ◽  
Diffusion Weighted Images ◽  
Tissue Contrast ◽  
Computer Based

Malignant pleural mesothelioma is a rare neoplasm with poor prognosis. CT is the first imaging technique used for diagnosis, staging, and assessment of therapy response. Although, CT has intrinsic limitations due to low soft tissue contrast and the current staging system as well as criteria for evaluating response, it does not consider the complex growth pattern of this tumor. Computer-based methods have proven their potentiality in diagnosis, staging, prognosis, and assessment of therapy response; moreover, computer-based methods can make feasible tasks like segmentation that would otherwise be impracticable. MRI, thanks to its high soft tissue contrast evaluation of contrast enhancement and through diffusion-weighted-images, could replace CT in many clinical settings.

scholarly journals Combined visualization of echinoderm hard and soft parts using contrast-enhanced micro-computed tomography

Zoosymposia ◽  
2019 ◽  
Vol 15 (1) ◽  
pp. 172-191 ◽  
Author(s):  
ALEXANDER ZIEGLER
Keyword(s):  
Computed Tomography ◽  
Soft Tissue ◽  
3D Visualization ◽  
Soft Part ◽  
Three Dimensional ◽  
Ethanol Solution ◽  
Micro Computed Tomography ◽  
Soft Tissue Contrast ◽  
Contrast Enhanced ◽  
Tissue Contrast

Recent studies have shown that micro-computed tomography (µCT) must be considered one of the most suitable techniques for the non-invasive, three-dimensional (3D) visualization of metazoan hard parts. In addition, µCT can also be used to visualize soft part anatomy non-destructively and in 3D. In order to achieve soft tissue contrast using µCT based on X-ray attenuation, fixed specimens must be immersed in staining solutions that include heavy metals such as silver (Ag), molybdenum (Mo), osmium (Os), lead (Pb), or tungsten (W). However, while contrast-enhancement has been successfully applied to specimens pertaining to various higher metazoan taxa, echinoderms have thus far not been analyzed using this approach. In order to demonstrate that this group of marine invertebrates is suitable for contrast-enhanced µCT as well, the present study provides results from an application of this technique to representative species from all five extant higher echinoderm taxa. To achieve soft part contrast, freshly fixed and museum specimens were immersed in an ethanol solution containing phosphotungstic acid and then scanned using a high-resolution desktop µCT system. The acquired datasets show that the combined visualization of echinoderm soft and hard parts can be readily accomplished using contrast-enhanced µCT in all extant echinoderm taxa. The results are compared with µCT data obtained using unstained specimens, with conventional histological sections, and with data previously acquired using magnetic resonance imaging, a technique known to provide excellent soft tissue contrast despite certain limitations. The suitability for 3D visualization and modeling of datasets gathered using contrast-enhanced µCT is illustrated and applications of this novel approach in echinoderm research are discussed.

Megavoltage CT in Helical Tomotherapy — Clinical Advantages and Limitations of Special Physical Characteristics

2009 ◽  
Vol 8 (5) ◽  
pp. 343-352 ◽  
Author(s):  
Florian Sterzing ◽  
Jörn Kalz ◽  
Gabriele Sroka-Perez ◽  
Kai Schubert ◽  
Marc Bischof ◽  
...  
Keyword(s):  
Soft Tissue ◽  
Position Control ◽  
Helical Tomotherapy ◽  
Orthopedic Implants ◽  
X Rays ◽  
Inverse Treatment Planning ◽  
Soft Tissue Contrast ◽  
Metal Implants ◽  
Megavoltage Ct ◽  
Tissue Contrast

Helical tomotherapy is a form of image-guided intensity-modulated radiotherapy that introduces the ring gantry concept into radiation oncology. The system is a combination of a therapeutic linear accelerator and a megavoltage CT-scanner. This work describes the clinical experience with megavoltage CT with 456 patients in more than 11000 fractions. It also provides a review of the current literature of the possibilities and limitations of megavoltage CT. Between July 2006 and October 2008 456 patients were treated with helical tomotherapy and a pretreatment megavoltage CT was performed in 98.1% of the 11821 fractions to perform position control and correction. CT image acquisition was done with 3.5 MV x-rays in the helical tomotherapy machine. MVCT was used for dose recalculations to quantify doses distributions in cases of changing geometry, tumor shrinkage or presence of metal implants. Inverse treatment planning for prostate cancer patients with bilateral hip replacements was performed based upon an MVCT. A mean 3D-correction vector of 7.1mm with a considerable variation was detected and immediately corrected. Mean shifts were lateral 0.9mm (sd 5.0mm), mean longitudinal shift 1.0mm (sd 5.1mm) and mean vertical shift 3.2mm (sd 5.2mm). The MVCT enables imaging of anatomical structures in the presence of dental metal or orthopedic implants. Especially in these cases, dose recomputations can increase the precision of dose calculations. Due to a mean 3d correction vector of more than 7mm and a variation of corrections of more than 5mm daily image-guidance is recommended to achieve a precise dose application. The MVCT shows evident advantages in cases with metal implants but has limitations due to a reduced soft tissue contrast. Compared with megavoltage cone-beam-CT the tomotherapy fan beam CT adds less extra dose fore the patient and has a better soft tissue contrast.

scholarly journals Development of an MRI-Based Workflow for Post-implant Dosimetry of Prostate Low-Dose-Rate (Ldr) Brachytherapy

2021 ◽  
Author(s):  
Reyhaneh Nosrati
Keyword(s):  
Soft Tissue ◽  
Dose Rate ◽  
Low Dose ◽  
Positive Contrast ◽  
Machine Learning Algorithms ◽  
Prostate Brachytherapy ◽  
Soft Tissue Contrast ◽  
Low Dose Rate ◽  
Ldr Brachytherapy ◽  
Tissue Contrast

Permanent implantation of low-dose-rate (LDR) brachytherapy seeds is a well-established treatment modality for patients with localized prostate cancer. The quality of the implant is assessed within 30 days following implantation through post-implant dosimetry. The standard recommended procedure for post-implant dosimetry is based on computed tomography (CT). CT provides excellent seed visualization and localization; however, due to poor soft tissue contrast and challenging anatomical identificatio,n it leads to significant interobserver variabilities. The current MRI-CT fusion-based workflow for post-implant dosimetry LDR prostate brachytherapy takes advantage of the superior soft tissue contrast of MRI but still relies on CT for seed visualization and detection, and it suffers from image fusion uncertainties and extra cost and logistics. The lack of positive contrast from brachytherapy seeds in conventional MR images remains a major challenge towards an MRI-only workflow for post-implant dosimetry of Low- Dose-Rate (LDR) brachytherapy. In this thesis, a clinically feasible MRI-based workflow has been developed for brachytherapy seed visualization and localization. The seed visualization is based on a novel Quantitative Susceptibility Mapping (QSM) algorithm. The proposed seed localization on QSM utilizes machine learning algorithms. The reliability of the proposed workflow has been validated on 23 patients by comparing the seed positions and final dosimetric parameters between the proposed MRI-only workflow and the clinical CT-MRI fusion-based approach and there was excellent agreement between the two methods.

scholarly journals Development of an MRI-Based Workflow for Post-implant Dosimetry of Prostate Low-Dose-Rate (Ldr) Brachytherapy

2021 ◽  
Author(s):  
Reyhaneh Nosrati
Keyword(s):  
Soft Tissue ◽  
Dose Rate ◽  
Low Dose ◽  
Positive Contrast ◽  
Machine Learning Algorithms ◽  
Prostate Brachytherapy ◽  
Soft Tissue Contrast ◽  
Low Dose Rate ◽  
Ldr Brachytherapy ◽  
Tissue Contrast

Permanent implantation of low-dose-rate (LDR) brachytherapy seeds is a well-established treatment modality for patients with localized prostate cancer. The quality of the implant is assessed within 30 days following implantation through post-implant dosimetry. The standard recommended procedure for post-implant dosimetry is based on computed tomography (CT). CT provides excellent seed visualization and localization; however, due to poor soft tissue contrast and challenging anatomical identificatio,n it leads to significant interobserver variabilities. The current MRI-CT fusion-based workflow for post-implant dosimetry LDR prostate brachytherapy takes advantage of the superior soft tissue contrast of MRI but still relies on CT for seed visualization and detection, and it suffers from image fusion uncertainties and extra cost and logistics. The lack of positive contrast from brachytherapy seeds in conventional MR images remains a major challenge towards an MRI-only workflow for post-implant dosimetry of Low- Dose-Rate (LDR) brachytherapy. In this thesis, a clinically feasible MRI-based workflow has been developed for brachytherapy seed visualization and localization. The seed visualization is based on a novel Quantitative Susceptibility Mapping (QSM) algorithm. The proposed seed localization on QSM utilizes machine learning algorithms. The reliability of the proposed workflow has been validated on 23 patients by comparing the seed positions and final dosimetric parameters between the proposed MRI-only workflow and the clinical CT-MRI fusion-based approach and there was excellent agreement between the two methods.

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