Search results for " Medical imaging"
showing 10 items of 1067 documents
An assessment of the hemorheological profile in patients with subclinical carotid atherosclerosis divided in relation to the number of cardiovascular…
2021
We present a cohort of 100 subjects [43 men and 57 women; median age 66.00(25)] who were tested using carotid ultrasound to identify subclinical carotid atherosclerosis (SCA). We have evaluated the behaviour of whole blood viscosity (WBV) at high (450 s–1) and low (0.51 s–1) shear rates, plasma viscosity (450–1), hematocrit and mean erythrocyte aggregation. When compared to normal control subjects, using the Mann-Whitney test, we observed in SCA patients a significant increase in WBV only. The results were substantial after having divided the SCA subjects according to the cardiovascular risk factors (CRFs) and the degree of insulin resistance; the research was performed using two surrogate …
Integrated non-invasive approach to atherosclerosis with cardiac CT and carotid ultrasound in patients with suspected coronary artery disease
2017
The aim of the study was to compare the atherosclerotic disease in the coronary and carotid arteries in patients who underwent non-invasive imaging for suspected stable coronary artery disease (CAD). 107 patients (64 men, age 59 ± 12) with atypical chest pain underwent cardiac CT (CCT) and carotid ultrasound (US) on the same day. Severity (obstructive or not-obstructive disease), location, shape, and composition of atherosclerotic plaques in the two districts were evaluated. Patients presented normal coronary arteries in 36 % (n = 38), not-obstructive CAD in 36 % (n = 39), and obstructive CAD in 28 % (n = 30), while had normal carotid arteries in 53 % (n = 57), not-obstructive disease in 44…
Association between radiography-based subchondral bone structure and MRI-based cartilage composition in postmenopausal women with mild osteoarthritis
2016
Summary Objective Our aim was to investigate the relation between radiograph-based subchondral bone structure and cartilage composition assessed with delayed gadolinium enhanced magnetic resonance imaging of cartilage (dGEMRIC) and T 2 relaxation time. Design Ninety-three postmenopausal women (Kellgren–Lawrence grade 0: n = 13, 1: n = 26, 2: n = 54) were included. Radiograph-based bone structure was assessed using entropy of the Laplacian-based image ( E Lap ) and local binary patterns ( E LBP ), homogeneity indices of the local angles (HI Angles,mean , HI Angles,Perp , HI Angles,Paral ), and horizontal (FD Hor ) and vertical fractal dimensions (FD Ver ). Mean dGEMRIC index and T 2 relax…
Necessary Catheter Diameters for Mechanical Thrombectomy with ADAPT
2017
BACKGROUND AND PURPOSE: Large-bore catheters allow mechanical thrombectomy in ischemic stroke by engaging and retrieving clots without additional devices (direct aspiration first-pass technique [ADAPT]). The purpose of this study was to establish a model for minimal catheter diameters needed for ADAPT. MATERIALS AND METHODS: We established a theoretic model for the calculation of minimal catheter diameters needed for ADAPT. We then verified its validity in 28 ADAPT maneuvers in a porcine in vivo model. To account for different mechanical thrombectomy techniques, we factored in ADAPT with/without a hypothetic 0.021-inch microcatheter or 0.014-inch microwire inside the lumen of the aspiration…
Under Pressure: Comparison of Aspiration Techniques for Endovascular Mechanical Thrombectomy.
2018
BACKGROUND AND PURPOSE: Blood flow should be interrupted during mechanical thrombectomy to prevent embolization of clot fragments. The purpose of our study was to provide a handy overview of the most common aspiration devices and to quantify their flow characteristics. MATERIALS AND METHODS: We assessed volumetric flow rates generated by a 60-mL VacLok vacuum pressure syringe, a Pump MAX aspiration pump, and a Dominant Flex suction pump connected to the following: 1) an 8F long sheath, 2) an 8F balloon-guide catheter, 3) an ACE 64 distal aspiration catheter, and 4) an AXS Catalyst 6 Distal Access Catheter. We used a water/glycerol solution, which was kept at a constant temperature of 20°C (…
GTVcut for neuro-radiosurgery treatment planning: an MRI brain cancer seeded image segmentation method based on a cellular automata model
2018
Despite of the development of advanced segmentation techniques, achieving accurate and reproducible gross tumor volume (GTV) segmentation results is still an important challenge in neuro-radiosurgery. Nowadays, magnetic resonance imaging (MRI) is the most prominent modality in radiation therapy for soft-tissue anatomical districts. Gamma Knife stereotactic neuro-radiosurgery is a minimally invasive technology for dealing with inaccessible or insufficiently treated tumors with traditional surgery or radiotherapy. During a treatment planning phase, the GTV is generally contoured by experienced neurosurgeons and radiation oncologists using fully manual segmentation procedures on MR images. Unf…
The Relationship between Gray Matter Quantitative MRI and Disability in Secondary Progressive Multiple Sclerosis
2016
Purpose: In secondary progressive Multiple Sclerosis (SPMS), global neurodegeneration as a driver of disability gains importance in comparison to focal inflammatory processes. However, clinical MRI does not visualize changes of tissue composition outside MS lesions. This quantitative MRI (qMRI) study investigated cortical and deep gray matter (GM) proton density (PD) values and T1 relaxation times to explore their potential to assess neuronal damage and its relationship to clinical disability in SPMS. Materials and Methods: 11 SPMS patients underwent quantitative T1 and PD mapping. Parameter values across the cerebral cortex and deep GM structures were compared with 11 healthy controls, and…
Whole-body magnetic resonance for staging and response assessment of lymphoma in a pregnant woman treated with antenatal chemotherapy
2017
A 32-year-old pregnant female presented with bilateral supraclavicular swelling, diffuse itching and right shoulder pain. After lymph nodal biopsy, a diagnosis of nodular sclerosis Hodgkin's lymphoma was obtained. A multidisciplinary team decided to start chemotherapy before the delivery, and whole-body MRI was used to stage the disease and evaluate the response after antenatal chemotherapy. This case shows that whole-body MRI is an attractive procedure that avoids radiation exposure and contrast administration, and enables staging and follow-up of a pregnant patient without risk to the fetus.
Predictors of mucositis in oropharyngeal and oral cavity cancer in patients treated with volumetric modulated radiation treatment: A dose-volume anal…
2015
Background The purpose of this study was to assess predictors of mucositis in oropharyngeal and oral cavity cancer after definitive or adjuvant volumetric modulated arc radiotherapy (VMAT) +/− chemotherapy. Methods Fifty patients were evaluated. Statistical analysis was performed for the following parameters as potential predictors of mucositis ≥ G2: total oral mucosa and oral mucosa minus target high-low radiation dose regions (planning target volumes [PTVs]), mean dose (Dmean), maximum dose (Dmax), chemotherapy, weight loss, and dysphagia. Results Mucositis ≥ G2 was found to be statistically related to chemotherapy, weight loss, dysphagia ≥ G2, total oral mucosa Dmean ≥50 Gy and Dmax ≥65 …
Focal Nodular Hyperplasia After Treatment With Oxaliplatin: A Multiinstitutional Series of Cases Diagnosed at MRI
2018
OBJECTIVE. Benign hepatic lesions may occur after chemotherapy treatment and may mimic metastases at imaging. We describe focal nodular hyperplasia (FNH) lesions diagnosed at MRI that occurred de n...