PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Imaging, Three-Dimensional”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 163 records · Page 9Linked to original sources
PubMed2026

How advances in chromosome conformation capture (3C) methods are reshaping our understanding of gene regulation in hematopoiesis.

The three-dimensional organization of the DNA within the nucleus plays a key role in regulating gene expression. Over the past two decades, advances in chromosome conformation capture (3C) technologies, in tandem with other methods, have shown that the genome forms a complex structure at multiple scales. Early studies identified large-scale structures such as chromosome territories, compartments and topologically associating domains (TADs). As the resolution of 3C techniques has improved, it has become possible to identify contacts between regulatory elements in detail and more recently, it has become possible to define intricate structures within cis-regulatory elements. In this chapter, we review the development of 3C-based methodologies and discuss the strengths and limitations of the different approaches. We examine how these technologies have refined our understanding of genome organization and gene regulation. Recent high-resolution studies reveal that chromatin architecture extends beyond classical domain structures to include nanoscale organization. Integration of 3C data with super-resolution imaging and molecular dynamics simulations supports a model in which genome folding is governed by the biophysical properties of chromatin.

Animals↗
PubMed2026

The Impact of Baseline Negative Emotions on Postoperative Quality of Life in Adolescent Idiopathic Scoliosis Patients: A 2-Year Follow-Up Study.

OBJECTIVE: Adolescent idiopathic scoliosis (AIS) is a three-dimensional spinal deformity that develops during puberty without a clear etiology. Beyond physical manifestations, AIS severely impacts adolescents' psychological and social well-being, leading to anxiety, depression, and low self-esteem. While advancements in surgical techniques have enhanced objective outcomes, existing studies on AIS have primarily focused on objective indices, with limited attention to the long-term impact of preoperative negative emotions on patient-reported subjective quality of life. METHODS: This was a retrospective cohort study. A total of 112 eligible AIS patients who underwent posterior spinal correction surgery between April and August 2023 were enrolled. Inclusion criteria included confirmed AIS, completion of 2-year follow-up, and informed consent; exclusion criteria included missing imaging/questionnaire data, comorbid psychiatric/neurological diseases, or prior spinal surgery. Patients were grouped using the Hospital Anxiety and Depression Scale (HADS) administered on admission. Quality of life was assessed preoperatively and 2&#x2009;years postoperatively using the Scoliosis Research Society-22 (SRS-22, evaluating self-image, mental health, pain, function, treatment satisfaction) and Short Form 36 Health Survey (SF-36, assessing 8 physical and mental health dimensions). Statistical analysis was performed via SPSS, using independent t-tests, paired t-tests, Mann-Whitney U test, and chi-square test. p&#x2009;<&#x2009;0.05 was considered significant. RESULTS: There were no significant differences in baseline characteristics (age, gender, BMI, surgical parameters, scoliosis type, preoperative/postoperative Cobb angles) between the two groups (all p&#x2009;>&#x2009;0.05). Preoperatively, SRS-22 and SF-36 scores showed no inter-group differences (all p&#x2009;>&#x2009;0.05). Postoperatively, the Negative Emotion Group had significantly lower scores in SRS-22 mental health (3.9&#x2009;&#xb1;&#x2009;0.3 vs. 4.5&#x2009;&#xb1;&#x2009;0.2) and treatment satisfaction (4.0&#x2009;&#xb1;&#x2009;0.3 vs. 4.6&#x2009;&#xb1;&#x2009;0.7), as well as SF-36 general health (68.6&#x2009;&#xb1;&#x2009;6.4 vs. 79.7&#x2009;&#xb1;&#x2009;13.3), role-emotional (61.3&#x2009;&#xb1;&#x2009;9.3 vs. 70.8&#x2009;&#xb1;&#x2009;9.7), and mental health (61.8&#x2009;&#xb1;&#x2009;14.3 vs. 68.9&#x2009;&#xb1;&#x2009;10.7) (all p&#x2009;<&#x2009;0.05); no inter-group differences were observed in physical function-related dimensions. Both groups showed significant improvements in physical function-related dimensions postoperatively. The Non-Negative Emotion Group also exhibited significant improvements in SRS-22 self-image/pain and SF-36 bodily pain (all p&#x2009;<&#x2009;0.05), while the Negative Emotion Group showed no significant improvements in these dimensions. CONCLUSIONS: Preoperative anxiety and depression do not affect the recovery of physical function in AIS patients after spinal correction surgery but significantly impede improvements in subjective quality of life dimensions, including mental health and treatment satisfaction. These findings highlight the need to integrate psychological assessment and targeted interventions into the perioperative management of AIS. Such a patient-centered approach will help optimize both physical and psychological outcomes, ultimately achieving comprehensive rehabilitation for AIS adolescents.

Humans↗
PubMed1978

Computed tomography of the head: clinical experience of the first 3000 scans with EMI scanner.

Computer tomography (CT) findings obtained from the first 3,000 scans on 2,031 patients were analyzed and discussions were made on various kinds of neurological diseases, especially from the neurosurgical point of view. CT showed an excellent resolution for three-dimensional morphological pattern of intracranial lesion with a high percentage of diagnostic accuracy as reported from other institutes, resulting in making much earlier morphological diagnosis of intracranial lesion possible than any other examination. Scan methods consisted of plain CT, contrast enhanced CT, and metrizamide CT cisternography. Sequential delayed enhanced CT offered more useful information for high diagnostic accuracy, particularly for nature of brain tumor. Metrizamide CT cisternography was performed for the evaluation of cerebrospinal fluid dynamics and diagnosis of skull base tumors. CT is a new, epoch-making and non-invasive diagnostic approach in neuroradiology and contributes to obtain the better achievement of neurosurgical results.

Adolescent↗
PubMed1976

Methods for measurement of cerebral blood flow in man.

A survey of the currently available methods for the measurement of cerebral blood flow in man is given. Many of the clinically important brain diseases such as tumors, stroke, brain trauma or epilepsy entail focal or regional flow alterations. Therefore a special emphasis is placed on methods allowing measurements of regional cerebral flow, rCBF. The intra-arterial 133Xenon injection method is now widely used as a standard method for rCBF measurement. It affords a good two-dimensional resolution when using a suitable dynamic gamma camera which allows a high counting rate to be recorded. But, due to the superposition of tissues the three-dimensional resolution is limited. This, in particular, means that smaller areas of ischemia (low flow) tend to be overlooked whereas local hyperemia is readily discerned. The 133Xenon inhalation method is less accurate, contaminated by extra-cerebral uptake, and insensitive both for detecting regional ischemia and regional hyperemia. The spatial resolution is also much more limited. For these reasons great caution must be exercised in interpreting the results. Methods yielding three-dimensional rCBF data will be needed in order to gain more precise information both on spatial localization and, especially, on ischemic areas. The most promising is computer-assisted axial tomography with freely diffusible radioactive isotopes or with x-rays using an intra-arterial injection of contrast. But, the available techniques are still too slow: in order to measure blood flow one "exposure" must be taken every second. Only a few methods give quantitative information of the blood flow in the human brain. This is mainly due to the inaccessibility of the brain within the skull and to the complexity of the cerebral arterial and venous systems. Before reviewing the various methods used in man, it should be mentioned, that much of the fundamental knowledge has been gained by methods only applicable to animals. Measurements of the diameter of the small arteries on the surface of the brain antedates even the classical studies of Roy and Sherrington (1890). This technique continues to be useful, modern technical improvements consisting of the use of micropipettes and a stereo microscope in combination with an image splitter and a television camera which allows the accurate assessment of diameter variations of a few percent [22]. Autoradiography of brain slices using diffusible indicators is the best quantitative method for measuring local blood flow in a great many parts of the brain [7, 45]. Microspheres are also being used, but it is still not quite clear that this technique gives reliable quantitative data in small masses of tissue [34, 41, 50].

Animals↗
PubMed1979

The [18F]fluorodeoxyglucose method for the measurement of local cerebral glucose utilization in man.

A method has been developed to measure local glucose consumption in the various structures of the brain in man with three-dimensional resolution. [18F]-2-deoxy-2-fluoro-D-glucose is used as a tracer for the exchange of glucose between plasma and brain and its phosphorylation by hexokinase in the tissue. A mathematical model and derived operational equation are used which enable local cerebral glucose consumption to be calculated in terms of the following measurable variables. An intravenous bolus of [18F]-2-deoxy-2-fluoro-D-glucose is given and the arterial specific activity monitored for a predetermined period of from 30 to 120 minutes. Starting at 30 minutes, the activity in a series of sections through the brain is determined with three-dimensional resolution by an emission tomographic scanner. The method was used to measure local cerebral glucose consumption in two normal volunteers. The values in gray matter structures range from 5.79 mg/100 g per minute in the cerebellar cortex to 10.27 in the visual cortex, whereas, in white matter structures, the values range from 3.64 mg/100 g per minute in the corpus callosum to 4.22 in the occipital lobe. Average values for gray matter, white matter, and whole brain metabolic rates, calculated as a weighted average based on the approximate volume of each structure, are 8.05, 3.80, and 5.90 mg/100 g per minute, respectively. The value of 5.9 mg/100 g per minute compares favorably with values previously reported.

Adult↗
PubMed1992

New techniques for three-dimensional data analysis in histopathology.

This paper describes two three-dimensional (3D) analytical techniques based on 3D mathematical morphology that have been found useful in quantifying the 3D spatial distribution of S-phase cells in a tubular tumor of the human breast. One technique is based on determining the normalized radial distribution of the S-phase cells with respect to the central axis of the tumor. The other technique is a novel extension of the polyhedra of Voronoi to quantify the distribution. The Voronoi polyhedron of a given S-phase cell nucleus is that polyhedron of minimal volume defined by planes all of which are perpendicular bisectors of the vectors extending from the given cell to all other S-phase cells in the tumor. Methods are demonstrated for generating these polyhedra and for histogramming their volumes. An illustration is given of using the histogram to sort the S-phase cells according to their 3D positional relationships. Displays showing the sorted cells in 3D and their associated Voronoi polyhedra are provided.

Adult↗
PubMed1992

Three-dimensional changes in direction and interrelationships among enamel prisms in the dog tooth.

This study describes the three-dimensional features of enamel prisms and their arrangement in dog teeth. Tangential semithin sections of demineralized tooth germ were serially cut from the enamel surface to the enamel-dentin junction. Straight rows of enamel prisms parallel or perpendicular to the meridian were selected at the enamel-dentin junction; these prisms were reconstructed from micrographs with a personal computer. Near the enamel-dentin junction, the arrangement of enamel prisms appeared regular. Viewed from the enamel surface, the cut-ends of the enamel prisms that were parallel to the meridian at the enamel-dentin junction appeared as a sine curve, with 16 enamel prisms forming one period. The enamel prisms in a row perpendicular to the meridian were parallel to each other and deflected to the left or right from the enamel-dentin junction. Away from the enamel-dentin junction, the periodicity of the prisms gradually disappeared. The sine curve formed by the cut-ends of prisms in a row parallel to the meridian became irregular, and prisms in rows perpendicular to the meridian crossed each other. The semithin sections showed belt-like zones arranged perpendicular to the meridian. Each belt-like zone consisted of enamel prisms oriented in the same direction, those in neighboring zones being oriented in opposite directions. The disappearance of the regular arrangement of prisms was related to changes in their location in the belt-like zones.

Animals↗
PubMed2026

The use of 3-dimensional (3D) printing in teaching musculoskeletal oncology for medical undergraduates.

INTRODUCTION: The approach to integrating relevant anatomy in the medical curriculum has been debated for many years. Current literature has explored the broad impact of 3D printing in medical education. However, there is little evidence on 3D printing for the teaching of musculoskeletal oncology (MSO). This is a self-controlled case series (SCCS) study that aims to analyse the effectiveness of 3D printed models in MSO in enhancing the learning experience, engagement and understanding of clinical and surgical anatomy for medical students. METHOD: A cross-sectional cohort study involving 75 clinical year medical students across 3 years from 2 medical schools that rotated through a single teaching hospital's orthopaedic department. Participants first viewed a set of computed-tomography (CT) images of a large pelvic osteosarcoma from a free open-source database, the Cancer Genome Atlas Sarcoma Collection (TCGA-SARC). A standardised 10-minute pre-intervention questionnaire which comprised 15 questions categorised by: 4 questions in 'anatomical knowledge', 7 questions in 'spatial awareness', 4 questions in 'surgical planning and complications', was administered to assess the baseline knowledge in their interpretation of the pathology via CT images only. Next, a 3D-printed model of the pelvic osteosarcoma, which included colour-coded adjacent structures, was provided as an adjunct to answer the same questionnaire. This concluded with a 5-point Likert scale feedback survey to gauge their perspectives and experience. RESULTS: The mean scores comparing their pre- and post-intervention assessment questionnaire increased by +1.34 from 8.15 (SD = 1.85) to 9.49 (SD = 1.7) (p < 0.001). The final year students had the greatest improvement of +1.54 from 8.00 (SD = 1.89) to 9.54 (SD = 1.59) (p = 0.004). There was no significant difference between the scores amongst the 2 medical schools. 91% of students agreed that the 3D model had helped them further their understanding of the anatomy of the sarcoma and 87% would want 3D printing models to augment their learning in anatomy. Baseline weaker students demonstrated significantly greater improvement in scores compared with baseline stronger students (mean difference +2.04 vs +0.30, p < 0.001). CONCLUSION: 3D printing is an effective teaching adjunct for musculoskeletal oncology surgical anatomy for medical undergraduates and could be used to enhance their understanding and learning experience. 3D models could be integrated in the teaching curriculum of surgical anatomy for undergraduate students.

Humans↗
PubMed1992

Bi- and three-dimensional CT study of carpal bone motion occurring in lateral deviation.

A computed tomography (CT) study of the right wrists of 15 volunteers and of 5 anatomical preparations in neutral position, radial (15 degrees) and ulnar (30 degrees) deviation enables to tackle the qualitative analysis of carpal bone motion. The CT Scans were analyzed and reconstructed in three dimensions by means of the Philips CAMRA S100 computer program. The results show that the capitate, the metacarpals II and III and, to a lesser extent, the trapezium and the trapezoid are poorly mobile. Our study points to the role of the flexor and extensor carpi ulnaris muscles in the stability of the internal carpus, confirming that the pisiform is a sesamoid bone in the flexor carpi ulnaris tendon. A model of longitudinal functional structure of the carpus during lateral deviation, intermediate between those of Navarro and Taleisnik, is proposed.

Adult↗
PubMed1979

A system for the three-dimensional construction, manipulation and display of microbiological models.

A system is described for building up serial sections into a three dimensional structure, incorporating density, that can be displayed and then further manipulated by rotation about three orthogonal axes. The initial application was to produce a computer model of a protein structure and to compare the diverse images obtained from rotation with the two dimensional images observed in related electron micrographs. To obtain sufficient contrast in the electron microscope images of protein structures, the specimens need to be stained and since this can cause some deformation of the observed images, it is also necessary to simulate ths possible effects of stain on the protein model. Because of the need to compare numerous orientations of the combined model, techniques are available either for speeding up the comparison or for obtaining better accuracy. The methods have been applied to the interpretation of electron micrograph images of microbiological specimens, where the three dimensional structure of the specimen is an important aid in understanding its biological function, but the techniques are also applicable to more general serial reconstruction requirements.

Adenoviridae↗
PubMedDate not supplied

Three-dimensional structures of the human alpha 2-macroglobulin-methylamine and chymotrypsin complexes.

The three-dimensional structures of chymotrypsin- and methylamine-treated negatively stained human alpha 2-macroglobulin have been determined by weighted back projection from electron microscope data. Projections of the reconstructions show good concordance with two-dimensional averages of both stained and frozen-hydrated molecules. The reconstructions reveal that the H-shaped front projection of the molecule is related to the smaller ellipsoidal end view by a rotation of 90 degrees about the crossbar (minor axis) of the H. This finding is in agreement with tilt studies. The reconstruction of the alpha 2-macroglobulin-methylamine reveals an hour-glass shaped void which is filled by the two proteinase molecules in the reconstruction of alpha 2-macroglobulin-chymotrypsin. Protein plugs which appear to block the exterior entrances to the cavity may function to prevent access of proteins to the encapsulated proteinase and serve to block its escape. Extensive thresholding of each reconstruction leaves a "backbone" consisting of two side-by-side rod-like structures, suggesting that this is the arrangement of the two protomeric units which form the molecule. Both structures show some departure from the expected symmetry. The asymmetries are robust features of the reconstructions and may reflect structurally asymmetric features of the transformation from the native to the chymotrypsin-treated form of the molecule.

Binding Sites↗
PubMedDate not supplied

Three-dimensional reconstruction of a complex of human alpha 2-macroglobulin with monomaleimido Nanogold (Au1.4nm) embedded in ice.

Cysteine 949 and glutamine 952 are known to be part of the thiol ester site of each of the four subunits of human alpha 2-macroglobulin (alpha 2M). The hydrolysis of this thiol ester bound to methylamine results in the incorporation of the amine and liberation of a free sulfhydryl group that can be specifically labeled. Therefore, a high-resolution marker specific for the sulfhydryl groups, the monomaleimido Nanogold (Au1.4nm) cluster was used to bind this amino acid. After cryoelectron microscopy, a three-dimensional reconstruction of the alpha 2M-Nanogold conjugates (alpha 2M-Au1.4nm) was achieved, revealing the internal location of the thiol ester sites in the transformed alpha 2M molecules. From this study we propose three possible locations for the cysteine 949.

Cysteine↗
PubMed1978

Special specimen preparation methods for image processing in transmission electron microscopy: a review.

One of the important developments in quantitative electron microscopy has been the application of optical and computer imaging methods to electron micrographs. In general these techniques of image analysis have been applied to electron micrographs from isolated biological structures prepared in the presence of various negative stains. To make full use of image processing techniques there are obvious advantages in preparing suitable specimens containing large areas of repeating features. However, the number of naturally occurring biological specimens exhibiting crystalline or paracrystalline features suitable for high resolution electron microscopy and subsequent image analysis is relatively small.Some recent experiments on the in vitro formation of crystalline and paracrystalline arrays from highly concentrated and purified isometric, filamentous and rod-like viruses is reviewed. The problems associated with the preparative procedures for producing two-dimensional and three-dimensional crystalline arrays are discussed together with the possibility of extending the negative staining-carbon film method for studying the gradual dissociation or assembly of viral components.

Computers↗
PubMed1975

Local cerebral blood volume determined by three-dimensional reconstruction of radionuclide scan data.

We developed a method to determine in man absolute values of local cerebral blood volume (LCBV) localized throughout the brain in three dimensions and presented in a cross-sectional picture format. Previously, absolute values of LCBV have been determined in vivo by stimulated X-ray fluorescence, but these determinations have been limited to one point in the brain at a time. All other previous estimates of LCBV by external emission counting have been contaminated by the significant contribution of blood in the overlying scalp and cranium. In our method, a transverse section scan is made after the injection of -99m-Tc-labeled red blood cells into a peripheral vein. Data processing then gives a point-to-point estimate of absolute radionuclide concentration analogous to an autoradiograph. After the concentration of blood activity is determined, counting data are converted to a two-dimensional map of LCBV representing a cross section at a known level of the brain. In a series of five baboons, the following equation was obtained for the regression plane that relates LCBV in the center of the brain to arterial carbon dioxide tension (P-ALPHA-CO2) and mean arterial blood pressure (MABP): LCBV equals 2.88 + 0.049P-ALPHA-CO2 MINUS 0.013MABP. In patients, LCBE values ranged from 2 to 4 ml/100 g depending on location; higher values corresponded to regions of cerebral cortex. Differences in blood volumes of focal brain lesions were also quantified.

Animals↗
PubMed1976

A three-dimensional reconstruction of the polygonal pattern on placental coated-vesicle membranes.

There is a surface structure on the coated vesicles of human placenta. Some features of this structure have been examined. Measurements of the polygonal network seen in surface views have been made and compared with measurements of structures projecting from vesicle walls in median sections. A 3-dimensional reconstruction of the vesicle shows the pattern to be one of raised ridges. Use of a goniometer to tilt the specimens has confirmed the assumption that both types of image obtained as from one structure. Although it is usually the case that vesicles are approximately spherical, some are definitely irregularly shaped. For this reason it is suggested that the walls of the polygons need not always be packed into a structure with a regular and precisely maintained pattern. Consideration of the surface structure in the light of current understanding of the cell membrane as a dynamic system leads to a possible explanation of the process of vesicle formation in this context and of the selective nature of uptake by micropinocytosis.

Humans↗
PubMed1979

Cardiac anatomy viewed systematically with two dimensional echocardiography.

The details of three-dimensional cardiac anatomy are complex, and structure recognition is difficult in tomograms produced with recently developed two-dimensional ultrasonic sector scanners. This article presents a method we have found useful for systematic inclusion of most cardiac structures during such echocardiographic examinations. Orthogonal planes, aligned parallel and perpendicular to the long or major left ventricular axis, are obtained from each of three transducer positions on the body surface. Moving this X-Y image plane through the heart perpendicular to the plane (z axis) allows the viewer to integrate the images into a mental picture of the whole structure. The illustrations are oriented as they are displayed by ultrasonic sector scanners so they aid rapid recognition of cardiac structures.

Echocardiography↗
PubMed1992

Complementary scanning electron microscopy: technical notes and applications.

This report introduces practical techniques and applications of complementary scanning electron microscopy (SEM). To identify the complementary structures at high magnification, we first made a montage pair of low magnification micrographs as a guide map. Consulting the map, we took complementary micrographs at high magnification. When taking a picture at high magnification, we drew the outline of the most prominent structures on a transparent plastic plate attached to the cathode-ray tube of a SEM. Then another picture of the complementary structures was taken after adjusting the complementary structures to the reverse image of the plastic plate. We performed three applications of the complementary SEM: 1) complementary observation of the epithelial underside and lamina propria of the rat urinary bladder; 2) complementary observation of the fractured Golgi apparatus; and 3) evaluation of specimen drying methods. After proper digestion of the rat urinary bladder using strong alkali, the epithelium was detached from the underlying lamina propria. On the basal side of the epithelium, the meshwork of grooves were visible. The observation of the corresponding lamina propria confirmed that the grooves were occupied by blood capillaries located in the uppermost part of the lamina propria. The complementary observation of the Golgi apparatus was useful for understanding its three-dimensional architecture. The observation on both complementary fractured surfaces of the Golgi apparatus from the mouse lacrimal gland demonstrated the continuity of the Golgi stacks. It was also effective for observing both the cis and trans side of the same Golgi stack. Complementary SEM was also useful for evaluating the specimen drying method.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗