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Tissue Characterization (tissue + characterization)
Selected AbstractsIntracardiac Fibroma in Nevoid-Basal Cell Carcinoma (Gorlin) Syndrome: Tissue Characterization by Strain Rate ImagingECHOCARDIOGRAPHY, Issue 1 2006Linda B. Pauliks M.D. No abstract is available for this article. [source] Noninvasive quantitative assessment of oral tongue cancer by intraoral ultrasonographyHEAD & NECK: JOURNAL FOR THE SCIENCES & SPECIALTIES OF THE HEAD AND NECK, Issue 4 2007Masashi Yamane DDS Abstract Background. To assess tissue characterization of oral tongue cancer and prediction of subclinical cervical lymph node metastasis, we investigated whether intraoral ultrasonography could be used in conjunction with a computer-aided diagnosis (CAD) system. Methods. The study population comprised 109 patients with presurgical, clinical T1N0 or T2N0 oral tongue squamous cell carcinoma who underwent partial glossectomy. All the patients were examined by preoperative intraoral and postoperative exvivo ultrasonography. To evaluate the ultrasonic imagesquantitatively, ultrasonographic parameters from tumor contour features were computed by using the proposed CAD system. The imaging results were correlated with histopathologic findings. Results. Oral tongue cancer was clearly identified in all patients by intraoral ultrasonography. Ultrasonic images of oral tongue cancer reflected the histopathologic structures. Subclinical cervical lymph node metastasis was predicted by intraoral ultrasonography. In a logistic regression analysis using the proposed CAD system, the diagnostic sensitivity, specificity, and accuracy for prediction of subclinical lymph node metastasis were 87.2%, 84.3%, and 85.3%, respectively. Conclusions. Intraoral ultrasonography in conjunction with the proposed CAD system allows tissue characterization and prediction of subclinical cervical lymph node metastasis. © 2006 Wiley Periodicals, Inc. Head Neck, 2007. [source] Cardiac amyloidosis: MR imaging findings and T1 quantification, comparison with control subjectsJOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 6 2007Gabriele A. Krombach MD Abstract In cardiac amyloidosis an interstitial deposition of amyloid fibrils causes concentric thickening of the atrial and ventricular walls. We describe the results of tissue characterization of the myocardium by T1 quantification and MRI findings in a patient with cardiac amyloidosis. The T1 time of the myocardium was elevated compared to that in individuals without amyloidosis. The T1 time of the myocardium was 1387 ± 63 msec (mean value obtained from four measurements ± standard deviation [SD]) in the patient with cardiac amyloidosis, while the reference value obtained from the myocardium of 10 individuals without known myocardial disease was 1083 ± 33 msec (mean value ± SD). In combination with other MR findings suggestive of amyloidosis, such as homogeneous thickening of the ventricular and atrial walls, thickening of the valve leaflets, restrictive filling pattern, and reduction of systolic function, T1 quantification may increase diagnostic confidence. J. Magn. Reson. Imaging 2007;25:1283,1287. © 2007 Wiley-Liss, Inc. [source] MRI tissue characterization of experimental cerebral ischemia in ratJOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 4 2003Hamid Soltanian-Zadeh PhD Abstract Purpose To extend the ISODATA image segmentation method to characterize tissue damage in stroke, by generating an MRI score for each tissue that corresponds to its histological damage. Materials and Methods After preprocessing and segmentation (using ISODATA clustering), the proposed method scores tissue regions between 1 and 100. Score 1 is assigned to normal brain matter (white or gray matter), and score 100 to cerebrospinal fluid (CSF). Lesion zones are assigned a score based on their relative levels of similarities to normal brain matter and CSF. To evaluate the method, 15 rats were imaged by a 7T MRI system at one of three time points (acute, subacute, chronic) after MCA occlusion. Then they were killed and their brains were sliced and prepared for histological studies. MRI of two or three slices of each rat brain (using two DWI (b = 400, b = 800), one PDWI, one T2WI, and one T1WI) was performed, and an MRI score between 1 and 100 was determined for each region. Segmented regions were mapped onto the histology images and scored on a scale of 1,10 by an experienced pathologist. The MRI scores were validated by comparison with histology scores. To this end, correlation coefficients between the two scores (MRI and histology) were determined. Results Experimental results showed excellent correlations between MRI and histology scores at different time points. Depending on the reference tissue (gray matter or white matter) used in the standardization, the correlation coefficients ranged from 0.73 (P < 0.0001) to 0.78 (P < 0.0001) using the entire dataset, including acute, subacute, and chronic time points. This suggests that the proposed multiparametric approach accurately identified and characterized ischemic tissue in a rat model of cerebral ischemia at different stages of stroke evolution. Conclusion The proposed approach scores tissue regions and characterizes them using unsupervised clustering and multiparametric image analysis techniques. The method can be used for a variety of applications in the field of computer-aided diagnosis and treatment, including evaluation of response to treatment. For example, volume changes for different zones of the lesion over time (e.g., tissue recovery) can be evaluated. J. Magn. Reson. Imaging 2003;17:398,409. © 2003 Wiley-Liss, Inc. [source] An integrated visualization system for surgical planning and guidance using image fusion and an open MRJOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 6 2001David T. Gering MS Abstract A surgical guidance and visualization system is presented, which uniquely integrates capabilities for data analysis and on-line interventional guidance into the setting of interventional MRI. Various pre-operative scans (T1- and T2-weighted MRI, MR angiography, and functional MRI (fMRI)) are fused and automatically aligned with the operating field of the interventional MR system. Both pre-surgical and intra-operative data may be segmented to generate three-dimensional surface models of key anatomical and functional structures. Models are combined in a three-dimensional scene along with reformatted slices that are driven by a tracked surgical device. Thus, pre-operative data augments interventional imaging to expedite tissue characterization and precise localization and targeting. As the surgery progresses, and anatomical changes subsequently reduce the relevance of pre-operative data, interventional data is refreshed for software navigation in true real time. The system has been applied in 45 neurosurgical cases and found to have beneficial utility for planning and guidance. J. Magn. Reson. Imaging 2001;13:967,975. © 2001 Wiley-Liss, Inc. [source] Discriminant analysis of autofluorescence spectra for classification of oral lesions in vivoLASERS IN SURGERY AND MEDICINE, Issue 5 2009J.L. Jayanthi MSc, MPhil Abstract Background and Objectives Low survival rate of individuals with oral cancer emphasize the significance of early detection and treatment. Optical spectroscopic techniques are under various stages of development for diagnosis of epithelial neoplasm. This study evaluates the potential of a multivariate statistical algorithm to classify oral mucosa from autofluorescence spectral features recorded in vivo. Study Design/Methods Autofluorescence spectra were recorded in a clinical trial from 15 healthy volunteers and 34 patients with diode laser excitation (404,nm) and pre-processed by normalization, mean-scaling and its combination. Linear discriminant analysis (LDA) based on leave-one-out (LOO) method of cross validation was performed on spectral data for tissue characterization. The sensitivity and specificity were determined for different lesion pairs from the scatter plot of discriminant function scores. Results Autofluorescence spectra of healthy volunteers consists of a broad emission at 500,nm that is characteristic of endogenous fluorophores, whereas in malignant lesions three additional peaks are observed at 635, 685, and 705,nm due to the accumulation of porphyrins in oral lesions. It was observed that classification design based on discriminant function scores obtained by LDA-LOO method was able to differentiate pre-malignant dysplasia from squamous cell carcinoma (SCC), benign hyperplasia from dysplasia and hyperplasia from normal with overall sensitivities of 86%, 78%, and 92%, and specificities of 90%, 100%, and 100%, respectively. Conclusions The application of LDA-LOO method on the autofluorescence spectra recorded during a clinical trial in patients was found suitable to discriminate oral mucosal alterations during tissue transformation towards malignancy with improved diagnostic accuracies. Lasers Surg. Med. 41:345,352, 2009. © 2009 Wiley-Liss, Inc. [source] Carotid vascular remodelling in patients with autosomal dominant polycystic kidney diseaseNEPHROLOGY, Issue 1 2009SHU RONG SUMMARY Aim: To study carotid vascular wall remodelling in patients with autosomal dominant polycystic kidney disease (ADPKD) using integrated backscatter signal (IBS) analysis. Methods: Included in the study were: 60 ADPKD patients with preserved renal function, including 32 patient with hypertension and 28 with normotension; 25 patients with essential hypertension; and 30 healthy volunteers. Carotid intima-media thickness (IMT) was measured by 2-D conventional ultrasonography. Acoustic tissue characterization of the carotid wall was assessed by IBS analysis, and the percentage of regions considered as fibromatosis was calculated in all groups. Results: Carotid IMT in hypertensive ADPKD patients (0.8 ± 0.05 vs 0.68 ± 0.02 mm, P < 0.01 and 0.8 ± 0.05 vs 0.56 ± 0.04 mm, P < 0.01 respectively) and patients with essential hypertension (0.79 ± 0.03 vs 0.68 ± 0.02 mm, P < 0.01 and 0.79 ± 0.03 vs 0.56 ± 0.0 4 mm, P < 0.01 respectively) was significantly greater than that of normotensive patients and healthy subjects. Carotid IMT in normotensive ADPKD patients was also significantly greater than that in healthy subjects (0.68 ± 0.02 vs 0.56 ± 0.04 mm, P < 0.01). Calibrated IBS (C-IBS) in hypertensive ADPKD patients was significantly greater than that in patients with essential hypertension and normotensive ADPKD patients (,21.2 ± 1.51 dB vs ,23.1 ± 1.61 dB, P < 0.05; ,21.2 ± 1.51 dB vs ,24.5 ± 1.34 dB, P < 0.01). C-IBS in normotensive ADPKD patients was significantly greater than that in healthy subjects (,24.5 ± 1.34 dB vs ,26.2 ± 1.69 dB, P < 0.01). The percentage of regions that could be considered as fibromatosis in hypertensive ADPKD patients was significantly greater than that in patients with essential hypertension and normotensive ADPKD patients (30.0% vs 22.4%, P < 0.05; 30.0% vs 17.9%, P < 0.01). The percentage of regions that could be considered as fibromatosis in normotensive ADPKD patients was significantly greater than that in healthy subjects (15.2% vs 10.3%, P < 0.01). Conclusion: Carotid remodelling occurs in the early stage of ADPKD and can be aggravated by hypertension. Fibrosis contributes to the vascular rearrangement. [source] Fluorescence Lifetime Spectroscopy of Glioblastoma Multiforme,PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 1 2004Laura Marcu ABSTRACT Fluorescence spectroscopy of the endogenous emission of brain tumors has been researched as a potentially important method for the intraoperative localization of brain tumor margins. We investigated the use of time-resolved, laser-induced fluorescence spectroscopy for demarcation of primary brain tumors by studying the time-resolved spectra of gliomas. The fluorescence of human brain samples (glioblastoma multiforme, cortex and white matter: six patients, 23 sites) was induced ex vivo with a pulsed nitrogen laser (337 nm, 3 ns). The time-resolved spectra were detected in a 360,550 nm wavelength range using a fast digitizer and gated detection. Parameters derived from both the spectral- (intensities from narrow spectral bands) and the time domain (average lifetime) measured at 390 and 460 nm were used for tissue characterization. We determined that high-grade gliomas are characterized by fluorescence lifetimes that varied with the emission wavelength (>3 ns at 390 nm, <1 ns at 460 nm) and their emission is overall longer than that of normal brain tissue. Our study demonstrates that the use of fluorescence lifetime not only improves the specificity of fluorescence measurements but also allows a more robust evaluation of data collected from brain tissue. Combined information from both the spectraland the time domain can enhance the ability of fluorescencebased techniques to diagnose and detect brain tumor margins intraoperatively. [source] Assessment of fetal lung development by quantitative ultrasonic tissue characterization: a methodical studyPRENATAL DIAGNOSIS, Issue 9 2004Ismail Tekesin Abstract Objectives This study was performed to evaluate the quantitative ultrasonic tissue characterization of the normal fetal lung development by using acoustic raw data captured after preprocessing. Methods One hundred and sixty-two patients with completed gestational ages between 22 and 37 weeks were enrolled in this study. Longitudinal and transverse sections of the fetal thorax and upper abdomen were imaged. A region of interest of constant size was defined and the tissue-specific gray scale was determined by using an interactive software. Results A total of 162 patients met the inclusion criteria. The echogenicity of the fetal lung showed a particular changing pattern during pregnancy: the mean gray value of the fetal lung (MGV) is almost the same as the MGV of the fetal liver at 22 and 23 weeks, decreases between 22 and 31 weeks and increases between 31 and 37 weeks. The MGV of the fetal liver decreases significantly from 24 weeks to 31 weeks and increases significantly again toward 37 weeks. We stated that the MGV of the lung is smaller than the MGV of the liver during 31 weeks of gestation and the relation reverses in late gestation. At term, the MGV of the liver is greater than the MGV of the lung. The lung-to-liver ratio is <1 between 24 and 29 weeks and >1 between 30 and 35 weeks. Conclusion The echogenicity of the fetal lung showed a particular changing pattern during pregnancy, which corresponds to morphologic changes of the fetal lung development. Copyright © 2004 John Wiley & Sons, Ltd. [source] | |||||||||||||