Search results for " MR imaging"
showing 10 items of 16 documents
Brain-core temperature of patients before and after orthotopic liver transplantation assessed by DWI thermometry
2018
To assess brain-core temperature of end-stage liver disease patients undergoing orthotopic liver transplantation (OLT) using a temperature measurement technique based on the apparent diffusion coefficient of the cerebrospinal fluid in the lateral ventricles. The study group was composed of 19 patients with a model for end-stage liver disease (MELD) score of 23.7 who underwent MR imaging before and after OLT. MR imaging studies were performed with a 1.5T MR scanner. Brain-core temperature (T: °C) was calculated using the following equation from the apparent diffusion coefficient (D) of the cerebrospinal fluid in the lateral ventricles: $$T = {{2256.74} \mathord{\left/ {\vphantom {{2256.74} {…
High-b-Value Diffusion-weighted MR Imaging of Benign Hepatocellular Lesions: Quantitative and Qualitative Analysis
2012
PURPOSE:To analyze the signal intensity (SI) of benign hepatocellular lesions in high-b-value diffusion-weighted (DW) magnetic resonance (MR) images and to compare the apparent diffusion coefficient (ADC) values of focal nodular hyperplasias (FNHs) with those of hepatocellular adenomas (HCAs). MATERIALS AND METHODS: This retrospective study was approved by institutional review board, with waiver of informed consent. Inclusion criteria were consecutive patients with diagnosed FNH or HCA who underwent MR imaging with a DW sequence of the liver at three b values, 0, 150, and 600 sec/mm2. The final study population included 67 patients (seven men, 60 women) with 90 hepatocellular lesions (54 FN…
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…
Automated prostate gland segmentation based on an unsupervised fuzzy C-means clustering technique using multispectral T1w and T2w MR imaging
2017
Prostate imaging analysis is difficult in diagnosis, therapy, and staging of prostate cancer. In clinical practice, Magnetic Resonance Imaging (MRI) is increasingly used thanks to its morphologic and functional capabilities. However, manual detection and delineation of prostate gland on multispectral MRI data is currently a time-expensive and operator-dependent procedure. Efficient computer-assisted segmentation approaches are not yet able to address these issues, but rather have the potential to do so. In this paper, a novel automatic prostate MR image segmentation method based on the Fuzzy C-Means (FCM) clustering algorithm, which enables multispectral T1-weighted (T1w) and T2-weighted (T…
Semi-automatic Brain Lesion Segmentation in Gamma Knife Treatments Using an Unsupervised Fuzzy C-Means Clustering Technique
2016
MR Imaging is being increasingly used in radiation treatment planning as well as for staging and assessing tumor response. Leksell Gamma Knife (R) is a device for stereotactic neuro-radiosurgery to deal with inaccessible or insufficiently treated lesions with traditional surgery or radiotherapy. The target to be treated with radiation beams is currently contoured through slice-by-slice manual segmentation on MR images. This procedure is time consuming and operator-dependent. Segmentation result repeatability may be ensured only by using automatic/semi-automatic methods with the clinicians supporting the planning phase. In this paper a semi-automatic segmentation method, based on an unsuperv…
Fully automatic multispectral MR image segmentation of prostate gland based on the fuzzy C-means clustering algorithm
2017
Prostate imaging is a very critical issue in the clinical practice, especially for diagnosis, therapy, and staging of prostate cancer. Magnetic Resonance Imaging (MRI) can provide both morphologic and complementary functional information of tumor region. Manual detection and segmentation of prostate gland and carcinoma on multispectral MRI data is not easily practicable in the clinical routine because of the long times required by experienced radiologists to analyze several types of imaging data. In this paper, a fully automatic image segmentation method, exploiting an unsupervised Fuzzy C-Means (FCM) clustering technique for multispectral T1-weighted and T2-weighted MRI data processing, is…
Neuronavigated-biopsy in the diagniosis of demyelinating pseudotumoral brain lesions. Case report.
2013
Introduction: Pseudotumoral-demyelinating lesions are typically characterized by severe difficulties in differential diagnosis from gliomas, metastatic tumors and abscesses. Marburg’s disease (MD) is an extremely rare and aggressive form of Mutiple Sclerosis (MS) with acute onset, rapid neurological deterioration, and poor prognosis. MRI images often show pseudotumoral lesions characterized by mild and focal or, sometimes, ring enhancement. Perhaps, radiological aspect can vary, making necessary hystopathological confirmation. Objectives: There is increasing interest in the role of surgical biopsy for a correct and early diagnosis of pseudotumoral demyelinating lesions. We report an histopa…
Using anatomic and metabolic imaging in stereotactic radio neuro-surgery treatments
2016
Peritumoral perfusion and proton spectroscopic MR imaging in the differentiation of gliomas and solitary metastases
2015
Purpose: To asses the value of peritumoural perfusion-weighted and proton spectroscopic MR imaging in preoperative grading of gliomas and in differentiating between primary gliomas and solitary metastases. Methods and Materials: Ten low-grade gliomas, eight high-grade gliomas, and ten metastases were prospectively evaluated with MR imaging, dynamic susceptibility contrast-enhanced perfusion imaging, and single-voxel proton MR spectroscopy before surgical resection or stereotactic biopsy. Maximal rCBV values and maximal Cho/Cr ratios were calculated from peritumoural region surrounding the tumour. Tumour grade presumed with these values was compared to histopathologic grading. Differences in…