Search results for " Contrast-enhanced"
showing 10 items of 23 documents
SIUMB recommendations for focal pancreatic lesions
2020
AbstractContrast-enhanced ultrasonography (CEUS) is increasingly being performed in Italy and Europe, particularly in the field of hepato-gastroenterology. Initially, it was mainly carried out to characterize focal hepatic lesions, but, since then, numerous studies have demonstrated its efficacy in the differential diagnosis of focal pancreatic pathologies (D’Onofrio et al. in Expert Rev Med Devices 7(2):257–273, 2010; Vidili et al. in J Ultrasound 22(1):41–51, 2019). The purpose of this paper is to provide Italian Medical Doctors with recommendations and thereby practical guidelines on the management of these patients. The present paper reports the final conclusions reached by the SIUMB gu…
Hyperpolarized 3helium gas as a novel contrast agent for functional MRI of ventilation.
2002
The use of inhaled hyperpolarized 3He gas in MRI is a recent approach for ventilation imaging. It has recently received enormous interest since it is capable of producing new and regional information on normal and abnormal lung ventilation. Promising preclinical and preliminary clinical results are the driving force to start phase II trials with patients suffering from obstructive and restrictive lung diseases.
Dynamic19F-MRI of pulmonary ventilation using sulfur hexafluoride (SF6) gas
2001
A new method for dynamic imaging of pulmonary wash-in and wash-out kinetics of inhaled sulfur hexafluoride (SF6) gas was developed. Measurements at the fluorine-19 Larmor frequency were performed in pigs using a gradient echo pulse sequence with 0.5 ms echo time and a measurement time of 9.1 s per image. Dynamic MRI was performed during wash-in and wash-out of SF6 gas in mechanically ventilated porcine lungs. A postprocessing strategy was developed for quantitative determination of wash-out time constants in the presence of noise. Mean wash-out constants were 4.78 ± 0.48 breaths vs. 4.33 ± 0.76 breaths for left and right lung when ventilation was performed with low tidal volume, and 1.73 ± …
Dynamic contrast-enhanced MRI parameters as biomarkers for the effect of vatalanib in patients with non-small-cell lung cancer.
2014
ABSTRACT: Aims: To assess the utility of dynamic contrast-enhanced MRI parameters in the demonstration of early antiangiogenic effects and as prognostic biomarkers in second-line treatment of advanced-stage non-small-cell lung cancer with vatalanib. Patients & methods: The transfer constant (Ktrans) and the initial area under the contrast concentration–time curve at 60 s (AUC60) were assessed in 46 patients. Changes were compared with response evaluation from computed tomography imaging and Response Evaluation Criteria In Solid Tumors guidelines. Results: Statistically significant mean reductions in Ktrans (38.4%; p < 0.0001) and AUC60 (24.9%; p < 0.0001) were found at day 2. Af…
Dynamic Fast Imaging Employing Steady State Acquisition Magnetic Resonance Imaging of the Vocal Tract in One Overtone Male Singer: Our Preliminary Ex…
2022
Summary Aims To demonstrate physiological changing of vocal tract's structures during overtone singing with commercial magnetic resonance imaging (MRI) Fast Imaging Employing Steady State Acquisition (FIESTA) dynamic sequence. Methods and Materials A 1.5 T MRI with a 16 channel head-and-neck coil and a FIESTA sequence were used. A temporal resolution of 0.155 sec (7 image/s). A single professional singer was studied. The MR acquisition is made while the singer performed a predetermined singing sequence. Three different overtone singing techniques were examined (L-technique, J-technique, and NG technique) and one effect (Ezengileer) applied to L-technique. For each overtone technique we eval…
Contrast-Enhanced Ultrasound Qualitative and Quantitative Characteristics of Parathyroid Gland Lesions
2021
Background and Objectives: preoperative differentiation of enlarged parathyroid glands may be challenging in conventional B-mode ultrasound. The aim of our study was to analyse qualitative and quantitative characteristics of parathyroid gland lesions, using multiparametric ultrasound protocol—B-mode, Colour Doppler (CD), and contrast-enhanced ultrasound (CEUS)—and to evaluate correlation with morphology in patients with hyperparathyroidism (HPT). Materials and Methods: consecutive 75 patients with 88 parathyroid lesions and biochemically confirmed HPT prior to parathyroidectomy were enrolled in the prospective study. B-mode ultrasound, CD, and CEUS were performed with the subsequent qualita…
Rectal cancer: Assessment of response to neoadjuvant chemoradiation by dynamic contrast-enhanced MRI
2012
Purpose To assess pretreatment functional and morphological tumor characteristics with magnetic resonance imaging (MRI) in advanced rectal carcinoma and to identify factors predicting response to neoadjuvant chemoradiation. Materials and Methods In a prospective study, 95 patients with rectal carcinoma underwent dynamic contrast-enhanced MRI before and after chemoradiation. Quantitative parameters were derived from a pharmacokinetic two-compartment model. Tumors were also characterized with regard to mucinous status at pretreatment high-resolution MRI as nonmucinous or mucinous. Response to treatment was defined as a downshift in the local tumor stage. Results The parameter k21 (contrast me…
Rectal cancer: Dynamic contrast-enhanced MRI correlates with lymph node status and epidermal growth factor receptor expression
2013
Purpose To evaluate correlations between dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and clinicopathologic data as well as immunostaining of the markers of angiogenesis epidermal growth factor receptor (EGFR) and CXC-motif chemokine receptor 4 (CXCR4) in patients with rectal cancer. Materials and Methods Presurgical DCE-MRI was performed in 41 patients according to a standardized protocol. Two quantitative parameters (k21, A) were derived from a pharmacokinetic two-compartment model, and one semiquantitative parameter (TTP) was assessed. Standardized surgery and histopathologic examinations were performed in all patients. Immunostaining for EGFR and CXCR4 was performed an…
Angiogenesis of cancer of the cervix. Contrast-enhanced dynamic MRT, histological quantification of capillary density and lymph system infiltration
1998
Purpose: It was the aim of this project to examine (i) the relationships between contrast-enhanced dynamic MR imaging derived characteristics and histologic microvessel density counts – a recognized surrogate of tumor angiogenesis – from tumors in patients with primary or recurrent cancer of the uterine cervix, and (ii) to correlate these parameters with lymphatic involvement (i. e. lymphatic channels) to assess tumorbiological aggressiveness in terms of lymphatic spread. Materials and methods: Pharmacokinetic MR imaging parameters (amplitude A, exchange rate constant k 21) were derived from contrast-enhanced dynamic MR imaging in thirty-three patients with biopsy proven cancer of the uteri…
MRI of tarantulas: morphological and perfusion imaging.
2005
This paper describes a study performed to evaluate the feasibility of using a 1.5-T whole-body magnetic resonance imaging (MRI) equipment, in combination with pharmacokinetic modeling, to obtain in vivo information about the morphology and perfusion of tarantulas (Eurypelma californicum). MRI was performed on three tarantulas using spin-echo sequences for morphological imaging and a rapid spoiled gradient-echo sequence for dynamic imaging during and after contrast medium (CM; Gd-DTPA) injection. Signal enhancement in dynamic measurements was evaluated with a pharmacokinetic two-compartment model. Spin-echo images showed morphological structures well. Dynamic images were of sufficient qualit…