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Results for “pathological imaging data”

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At least 235 records · Page 13Linked to original sources

PubMed2004

Hepatocellular nodules in cirrhosis: focus on diagnostic criteria on liver biopsy. A Western experience.

The spectrum of so-called space-occupying small (0.5-2.5 cm) sizable nodules arising in the cirrhotic liver includes a series of hyperplastic (large regenerative), dysplastic (low- and high-grade dysplastic), and malignant hepatocellular (well-differentiated hepatocellular carcinoma, HCC) nodules. Major progress in their classification and understanding was achieved through image analysis techniques and careful histological dissection of explanted native livers. Needless to say, the actual understanding of their natural history is crucial to a proper histological classification. The differential diagnosis of these hepatocellular nodules is difficult, particularly on biopsy specimens of focal liver lesions revealed by ultrasound (US), taken during the follow-up of cirrhotic patients. In this study we attempted to summarize, on the basis of our experience, essential clinicopathological features useful to distinguish the different nodules on needle biopsy. Synoptic tables of differential diagnosis and figures of elementar lesions, which have to be looked for, are provided. Only the continuous integration of clinical features, image analysis information of pathological findings, and follow-up data allows establishing the autonomy of these polymorphic and controversial entities and the boundaries between them.

Biopsy↗

PubMed2002

Pulsed Z-spectroscopic imaging of cross-relaxation parameters in tissues for human MRI: theory and clinical applications.

A new method of pulsed Z-spectroscopic imaging is proposed for in vivo visualization and quantification of the parameters describing cross-relaxation between protons with liquid-like and solid-like relaxation properties in tissues. The method is based on analysis of the magnetization transfer (MT) effect as a function of the offset frequency and amplitude of a pulsed off- resonance saturation incorporated in a spoiled gradient-echo MRI pulse sequence. The theoretical concept of the method relies on an approximated analytical model of pulsed MT that provides a simple three-parameter equation for a pulsed steady-state Z-spectrum taken far from resonance. Using this model, the parametric images of cross-relaxation rate constant, content, and T(2) of the semisolid proton fraction can be reconstructed from a series of MT-weighted images and a coregistered T(1) map. The method was implemented on a 0.5 T clinical MRI scanner, and it provided high-quality 3D parametric maps within an acceptable scanning time. The estimates of cross-relaxation parameters in brain tissues were shown to be quantitatively consistent with the literature data. Clinical examples of the parametric images of human brain pathologies (multiple sclerosis and glioma) demonstrated high tissue contrast and clear visualization of the lesions.

Brain↗

PubMed1998

Dynamic contrast-enhanced MR imaging of the entire breast with spectral-selective inversion fast three dimensional sequence.

Dynamic contrast-enhanced images with high spatial and temporal resolutions were acquired with a fast 3D spoiled gradient echo (SPGR) sequence using spectral selective inversion recovery (IR) pulse. Five healthy volunteers and 12 patients with 14 pathologically proven breast lesions were studied. Fat suppressed volume image data covering the entire breast were obtained with a sufficient spatial resolution (0.9 x 1.5 x 3.0 mm3) and an imaging time of 57 s. By using the criteria including peripheral enhancement and presence of spiculation, sensitivity, specificity, and accuracy in detecting malignant lesions were 88.9, 80.0 and 85.7%, respectively. Although the C/N and S/N ratios were approximately 30% less than those of the conventional fat suppressed 3D technique, fast 3D SPGR imaging with spectral IR method demonstrated sufficient image quality for both time intensity analysis and morphological evaluation of the breast lesions with a data acquisition time less than half of the conventional method. This technique can substantially improve spatial and temporal resolutions of dynamic MR images of the breast and will be useful in evaluating malignant and benign breast lesions.

Adipose Tissue↗

PubMed1990

Echocardiography in coronary artery disease.

Echocardiography has a major role in the evaluation of patients with CAD. To obtain the maximal amount of information using this technique, certain basic principles relating to regional myocardial mechanics during ischemia and flow-function relations are required. In addition, a detailed knowledge of cardiac anatomy and the three-dimensional orientation of the heart within the chest cavity is required to access meaningful information from two-dimensional planes. Furthermore, skill is also required in acquiring data in proper imaging planes and in separating true (actual pathology) from the false (artifacts, etc.). Echocardiography is not a "mature" technology. It is still developing and it is sometimes difficult to keep up with the advances. However, keeping abreast of these developments is essential to fully exploit the advantages of this technique. In addition, knowledge of the ever-changing aspects of CAD is required in order to correctly interpret visual information in context of a particular patient. Finally, more clinical studies are needed to further define the role of echocardiographic techniques in patients with CAD.

Blood Flow Velocity↗

PubMed2003

In vivo real-time freehand palpation imaging.

Previous experience with laboratory fixtures and off-line processing of elasticity data showed that problems occurring in data acquisition often resulted in poor elasticity image quality. A system for real-time estimation and display of tissue elastic properties using a clinical ultrasonic imaging system has been developed. A brief description of that system and the initial clinical tests of that system are reported. Experience with real-time freehand elasticity imaging shows that images with high contrast-to-noise ratios are consistently obtained. Images of breast lesions were acquired with freehand palpation using standard linear-array ultrasound (US) transducers. Results in volunteer patients show that high-quality elasticity images are easily obtained from in vivo breast studies. The key element to successful scanning is real-time visual feedback of B-mode and strain images that guide the patient positioning and compression direction. Results show that individual images of axial strain in tissues can be quite misleading, and that a "movie loop" of side-by-side B-mode and strain images provides significantly more information. Our preliminary data suggest that the strain image sequences for various breast pathologies are unique. For example, strain images of fibroadenomas lose contrast with increasing precompression, but those of invasive ductal carcinoma have high negative contrast (dark relative to "normal" tissue) for a wide range of precompression. In addition, a comparison of the lesion area measured in B-mode vs. strain images, for a representative image from the sequence, appears to be a sensitive criterion for separating invasive ductal carcinoma from cyst and fibroadenoma.

Algorithms↗

PubMed2006

Muscle imaging in dominant core myopathies linked or unlinked to the ryanodine receptor 1 gene.

OBJECTIVE: To characterize the muscle involvement of patients with central core disease (CCD) caused by mutations in the ryanodine receptor 1 gene (RYR1) and to compare these findings with those from patients with core myopathies unlinked to the RYR1 gene. METHODS: We performed a systematic muscular imaging assessment in 11 patients with an RYR1 gene mutation and compared these findings with those of 5 patients from two unrelated families with autosomal dominant core myopathies not linked to RYR1, ACTA1, or MYH7 gene loci. RESULTS: All patients with RYR1 CCD had a characteristic pattern with predominant involvement of the gluteus maximus, adductor magnus, sartorius, vastus intermediolateralis, soleus, and lateral gastrocnemius muscles. In contrast, muscle CT in the first family not linked to RYR1 showed predominant affection of the gluteus minimus and hamstring muscles, whereas the second family presented with predominant involvement of the gluteus minimus, vastus intermediolateralis, tibialis anterior, and medial gastrocnemius muscles. In addition to muscle imaging data, we present detailed information on the clinical and pathologic findings of these novel phenotypes of core myopathies not linked to RYR1. CONCLUSIONS: Our data suggest genetic heterogeneity in autosomal dominant core myopathies and the existence of additional unidentified genes.

Chromosome Disorders↗

PubMed2006

Computer-assisted analysis of 4D cardiac MR image sequences after myocardial infarction.

OBJECTIVES: Spatial-temporal MR image sequences of the heart contain information about shape and motion changes and pathological structures after myocardial infarction. In this paper a Heart Analysis Tool (HeAT) for the quantitative analysis of 4D MR image sequences of infarct patients is presented. METHODS: HeAT supports interactive segmentation of anatomical and pathological structures. Registration of Cine- and DE-MR image data is applied to enable their combined evaluation during the analysis process. Partitioning of the myocardium in segments enables the analysis with high local resolution. Corresponding segments are generated and used for inter/intrapatient comparison. Quantitative parameters were extracted and visualized. RESULTS: Parameters like endocard movement in the infarcted area of six infarct patients were computed in HeAT. Parameters in the infarct area show the expected dysfunctional characteristics. Based on theses parameters passive endocardial movement and myocardial areas with decreased contraction could be identified. CONCLUSION: In contrast to other software tools HeAT supports the combination of contour information of Cine-MR and DE-MR, local analysis with high resolution and inter/intra patient comparison. HeAT enables an observer-independent evaluation of the complex cardiac image data. Using HeAT in further studies can increase the understanding of left ventricle (LV) remodeling.

Algorithms↗

PubMedDate not supplied

A review of 1H nuclear magnetic resonance relaxation in pathology: are T1 and T2 diagnostic?

The longitudinal (T1) and transverse (T2) proton (1H) nuclear magnetic resonance (NMR) relaxation times of pathological human and animal tissues in the frequency range 1-100 MHz are archived, reviewed, and analyzed as a function of tissue of origin, NMR frequency, temperature, species, and in vivo versus in vitro status. T1 data from specific disease states of the bone, brain, breast, kidney, liver, muscle, pancreas, and spleen can be characterized by simple dispersions of the form T1 = AvB in the range 1-100 MHz with A and B empirically determined pathology-dependent constants. Pathological tissue T2 values are essentially independent of NMR frequency. Raw relaxation data, best-fit T1 parameters A and B, and the mean T2 values, are tabulated along with standard deviations and sample size to establish the normal range of pathological tissue relaxation times applicable to NMR imaging or in vitro NMR examination. Statistical analysis of relaxation data, assumed independent, reveals that most tumor and edematous tissue T1 values and some breast, liver, and muscle tumor T2 values are significantly elevated (p greater than or equal to 0.95) relative to normal, but do not differ significantly from other tumors and pathologies. Statistically significant abnormalities in the T1 values of some brain, breast, and lung tumors, and most pathological tissue T2 values could not, however, be demonstrated in the presence of large statistical errors. Both T1 and T2 in uninvolved tissue from tumor-bearing animals or organs do not demonstrate statistically significant differences from normal when considered as a group, suggesting no appreciable systemic effects associated with the presence of tumors compared to the statistical uncertainty. Statistical prediction analysis for both T1 and T2 indicates that of all the tissues studied, only liver hepatoma can be reliably distinguished from normal liver based on a single T1 measurement (p greater than or equal to 0.95) given the scatter in the current published data. Indeed, data scatter, not easily attributable to temperature, species, in vivo versus in vitro status, the inclusion of implanted or chemical induced tumors, or the possible existence of multiple component relaxation, is recognized as the major factor inhibiting the diagnostic utility of quantitative NMR relaxation measurements. Malignancy indexes that combine T1 and T2 data as a diagnostic indicator suffer similar problems of uncertainty. The literature review reveals a dearth of information on the temperature and frequency dependence of pathological tissue relaxation and the possible existence of multiple relaxation components.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

PubMed1996

Technetium-99m sestamibi parathyroid localization is accurate enough for scan-directed unilateral neck exploration.

A retrospective study was conducted into technetium-99m sestamibi imaging of primary hyperparathyroidism to determine the accuracy of identification and localization of parathyroid pathology. Of 56 patients studied, 48 had full preoperative scan data, operative data and pathological results analysed. Overall scan accuracy was 96 per cent. For single gland pathology (adenoma) imaging had a sensitivity of 97 per cent, a specificity of 100 per cent and a positive predictive value of 100 per cent. For single gland disease the side was correctly identified in 100 per cent of cases and the site in 94 per cent, but the respective values were only 82 and 79 per cent for multiple gland pathology. Technetium-99m sestamibi imaging is highly sensitive and accurate for primary hyperparathyroidism, with sufficient positive predictive value and accuracy in single gland disease to allow scan-directed unilateral neck exploration.

Follow-Up Studies↗

PubMed2002

Evaluation and surgical management of isolated sphenoid sinus disease.

OBJECTIVES: To evaluate the pathologic conditions, preoperative evaluation, treatment, and clinical outcomes associated with sphenoid sinus disease. DESIGN: Retrospective study. SETTING: Tertiary university-based referral center. PATIENTS: All patients with isolated sphenoid sinus disease managed surgically or in which surgery was considered a primary treatment option. MAIN OUTCOME MEASURES: Demographic data, presenting signs and symptoms, endoscopic and imaging findings, surgical management, surgical pathology, and clinical outcomes were investigated in patients presenting with sphenoid sinus disease to the Medical College of Wisconsin, Milwaukee, between January 1, 1991, and December 31, 2001. RESULTS: The study population included 17 women and 12 men with a mean age of 52.3 years (range, 15-82 years). The most common presenting symptom was headache (20 patients [69%]). Imaging evaluation included computed tomography and/or magnetic resonance imaging studies in all cases. Sphenoid sinus abnormality was variable and included sinusitis (11 patients [38%]), tumor (7 [24%]), mucocele (5 [17%]), fungal process (3 [10%]), and cerebrospinal fluid fistula (3 [10%]). Twenty-one cases (72%) were managed endoscopically and 4 (14%) were managed with a transseptal approach. One patient (3%) underwent combined extracranial-endoscopic transnasal approach, while another (3%) underwent a midface degloving approach. The remaining 2 patients (7%) did not undergo surgical intervention. CONCLUSIONS: Given the high prevalence of noninflammatory lesions within the sphenoid sinus, thorough preoperative evaluation is imperative. Initially, this should include nasal endoscopy and computed tomography to help define the location, extent, and character of the lesion. In some cases, magnetic resonance imaging may help further define the nature and extent of a lesion. Angiography should be considered if a vascular lesion is suspected. The clinical and imaging findings should all be taken into consideration when the surgical approach is planned.

Adolescent↗

PubMed2004

Functional-anatomical image fusion in neuroendocrine tumors.

Nuclear medicine provides physiologic and functional data for normal and pathologic organs but often the clear definition of the sites of radiotracers' uptake are difficult. Radiological methods are able to identify structural changes in a detailed way, but do not give precise information on function of organs or pathologic lesions. The registration and fusion of nuclear medicine studies with structural information obtained by radiological exams allows the precise correlation of functional and anatomical data. Software-based fusion of independently performed nuclear medicine and morphologic studies is uncertain of success and the alignment procedures are labor intensive. Recently, a new imaging device combining a dual-head, variable angle gamma camera with a low-dose x-ray tube has been introduced; the acquired single-photon emission computed tomography (SPECT) and x-ray computed tomography (CT) images are coregistered by means of the hardware in the same session. This new technology can be particularly useful when applied to scintigraphic procedures in neuroendocrine tumors. In-111 pentetreotide and radiolabeled MIBG play an important role in the study of patients with these tumors; the addition of anatomical maps provides a precise localization of SPECT findings and allows the exclusion of disease in sites of physiologic tracer uptake. SPECT/CT fused images are able to provide additional information that improves the accuracy of SPECT interpretation and leads to changes in therapeutic options, so enhancing the clinical role of nuclear medicine in evaluating patients with neuroendocrine tumors.

Humans↗

PubMed2003

Automated fiducial marker detection for patient registration in image-guided neurosurgery.

OBJECTIVE: The registration of applied fiducial markers within the preoperative data is often left to the surgeon, who has to identify and tag the center of each marker. This is both time-consuming and a potential source of error. For this reason, the development of an automated procedure was desirable. In this study, we have investigated the accuracy of a software algorithm for detecting fiducial markers within the navigation data set. The influence of adjustable values for accuracy and threshold on the sensitivity and specificity of the detection process, as well as the time gain, was investigated. PATIENTS AND METHODS: One hundred MP-RAGE MRI data sets of patients with different pathologies who were scheduled for image-guided surgery were used in this study. A total of 591 applied fiducial markers were to be detected using the algorithm of the software VVPlanning 1.3 (BrainLAB, Heimstetten, Germany) on a Pentium II standard PC. The size value of a marker in the y-direction is called "accuracy" and depends on the slice thickness. "Threshold" describes the gray level above which the algorithm starts searching for pixel clusters. The threshold value was changed stepwise on the basis of a constant "accuracy" value. The "accuracy" value was changed on the basis of that threshold value at which all markers were detected correctly. RESULTS: The time needed for automatic detection varied between 12 s and 25 s. An optimum value for adjustable marker size was found to be 1.1 mm, with 8 undetected markers (1.35%) and 7 additionally detected structures (1.18%) out of 591. The mean gray level (Threshold) for all data sets above which marker detection was correct was 248.9. The automatic detection of markers was good for higher gray levels, with 11 missed markers (1.86%). Starting the algorithm at lower gray levels led to a decreased incidence of missed markers (0.17%), but increased the incidence of additionally detected structures to 27.92%. CONCLUSION: The automatic marker-detection algorithm is a robust, fast and objective instrument for reliable fiducial marker registration when used with optimum settings for both threshold and accuracy.

Adolescent↗

PubMed1995

The striated cerebellum: an MR imaging sign in Lhermitte-Duclos disease (dysplastic gangliocytoma).

PURPOSE: To correlate the magnetic resonance (MR) imaging features of and histologic findings in Lhermitte-Duclos disease (LDD) (dysplastic gangliocytoma). MATERIALS AND METHODS: MR imaging and histologic data from eight patients with the diagnosis of LDD were retrospectively reviewed. Gross pathologic specimens were also available in one case. Contrast material-enhanced MR images were obtained in seven of the eight patients. RESULTS: At MR imaging, a non-enhancing mass in the cerebellar hemisphere was characterized by a striated pattern of hyperintensity on T2-weighted images and corresponding hypointensity on T1-weighted images, which represented the abnormally thickened folia. None of the masses demonstrated enhancement. CONCLUSION: Most other cerebellar masses destroy the folial pattern and show enhancement. The nonenhancing striated MR appearance of thickened folia in patients with LDD is distinctive and should suggest this diagnosis.

Adult↗

PubMed2001

SPECT perfusion imaging in the diagnosis of Alzheimer's disease: a clinical-pathologic study.

OBJECTIVE: Numerous studies have suggested that temporoparietal hypoperfusion seen on brain imaging with SPECT may be useful in diagnosing AD during life. However, these studies have often been limited by lack of pathologic validation and unrepresentative samples. The authors performed this study to determine whether SPECT imaging provides diagnostically useful information in addition to that obtained from a clinical examination. METHODS: Clinical data and SPECT images were collected prospectively, and patients were followed to autopsy. Clinical history, pathologic findings, and SPECT images were each evaluated by raters blind to other features, and clinical and SPECT diagnoses were compared with pathologic diagnoses. The study population consisted of 70 patients with dementia, followed to autopsy; 14 controls followed to autopsy; and 71 controls (no autopsy performed). The primary outcome was the likelihood of a pathologic diagnosis of AD given a positive clinical diagnosis, a positive SPECT diagnosis, and both. RESULTS: When all participants (patients and controls) were included in the analysis, the clinical diagnosis of "probable" AD was associated with an 84% likelihood of pathologic AD. A positive SPECT scan raised the likelihood of AD to 92%, whereas a negative SPECT scan lowered the likelihood to 70%. SPECT was more useful when the clinical diagnosis was "possible" AD, with the likelihood of 67% without SPECT, 84% with a positive SPECT, and 52% with a negative SPECT. Similar results were found when only patients with dementia were included in the analysis. CONCLUSIONS: In the evaluation of dementia, SPECT imaging can provide clinically useful information indicating the presence of AD in addition to the information that is obtained from clinical evaluation.

Aged↗

PubMed2006

Role of 3D CT in the evaluation of the temporal bone.

In recent years, three-dimensional (3D) multiplanar reformatted images from conventional cross-sectional computed tomographic (CT) data have been increasingly used to better demonstrate the anatomy and pathologic conditions of various organ systems. Three-dimensional volume-rendered (VR) CT images can aid in understanding the temporal bone, a region of complex anatomy containing multiple small structures within a relatively compact area, which makes evaluation of this region difficult. These images can be rotated in space and dissected in any plane, allowing assessment of the morphologic features of individual structures, including the small ossicles of the middle ear and the intricate components of the inner ear. The use of submillimeter two-dimensional reconstruction from CT data in addition to 3D reformation allows depiction of microanatomic structures such as the osseous spiral lamina and hamulus. Furthermore, 3D VR CT images can be used to evaluate various conditions of the temporal bone, including congenital malformations, vascular anomalies, inflammatory or neoplastic conditions, and trauma. The additional information provided by 3D reformatted images allows a better understanding of temporal bone anatomy and improves the ability to evaluate related disease, thereby helping to optimize surgical planning.

Bone Diseases↗

PubMed1990

Magnetic resonance imaging in cervical cord birth injury.

Three children who sustained cervical cord injury due to birth trauma are described. The clinical and radiological data, and the central nervous system pathology of one child, illustrate the advantages and feasibility of magnetic resonance imaging in ventilator-dependent children with cervical cord lesions.

Birth Injuries↗

PubMed2006

Optical coherence tomography of peripheral retinal lesions in enucleated human eye specimens with histologic correlation.

PURPOSE: To report optical coherence tomography (OCT) histologic correlations of three common peripheral retinal lesions and to explore the feasibility of the use of OCT to image retinal pathologic conditions in fixed tissue specimens. DESIGN: Experimental study. METHODS: We studied peripheral retinal lesions that were available to us in 11 formalin-fixed caps of seven human eyes that had been enucleated previously for choroidal melanoma. OCT scans were performed through these lesions, and the images were correlated with corresponding histologic sections. RESULTS: Three peripheral retinal diseases that included cystoid degeneration, localized retinal detachment, and paving stone degeneration were imaged successfully, and their optical characteristics correlated well with their histologic data. CONCLUSION: We explored potential utility for OCT imaging of peripheral retinal pathologic conditions in fixed tissue specimens. That these OCT images correlate with findings from histologic sections suggests a possible role for OCT in the eye pathology laboratory.

Choroid Neoplasms↗

PubMed1999

Standardization of magnetization transfer imaging for multicenter studies.

Magnetization transfer (MT) techniques may be applied to magnetic resonance imaging (MRI) to evaluate the inherent relaxation properties of heterogeneous tissues. In addition to providing a unique contrast mechanism for the purpose of qualitative imaging, the MT effect may be quantified by various means to provide useful data that relate either to the pathological or associated clinical features of multiple sclerosis (MS) and other neurological disorders. The variable and relatively unpredictable course of neurological disorders such as MS often necessitates the study of large patient cohorts in multiple MRI centers to define either the natural history of the disease or its modification by potential therapies. For multicenter studies, precision (reproducibility, or lack of random error) and accuracy (closeness to the truth, or lack of systematic error) are important requirements for the acquisition of standardized and comparable data. For serial studies, quality assurance is important to determine pathological change from fluctuation in scanner performance. This review addresses how MT imaging techniques may be utilized to provide standardized and clinically relevant measures.

Brain↗