Three-dimensional Dynamic Imaging Research Articles

Parametric Imaging of Tumor Perfusion with Deuterium Magnetic Resonance Imaging

Imaging of the vasculature and its functioning over the entire lesion may significantly aid in cancer diagnosis, assessment of prognosis, and therapeutic evaluation. In the current study we present a dynamic three-dimensional deuterium magnetic resonance imaging method that determines the intravascular volume fraction and water perfusion rate at a resolution of 2 mm2/pixel. The method was tested and utilized to characterize the vasculature of orthotopic MCF7 human breast cancer tumors in CD1-NU athymic mice. A new algorithm based on Patlak's kinetic model was developed to analyze the dynamic images acquired during and after termination of infusion with deuterated water. The resulting parametric maps spanned a wide range from 0.4 to 35.2% for the intravascular volume fraction and from 4 × 10−6 to 3.9 × 10−3 min−1 for the perfusion rate and exhibited high intratumoral and intertumoral heterogeneity at both parameters. The intravascular volume fraction did not correlate with the corresponding perfusion rate, demonstrating the irregular outgrowth of tumor neovascularization. Averaging the data or analyzing at spatially degraded resolution completely masked the presence of both “hot spots” and hypoxic loci, highlighting the critical importance of high spatial resolution. The method is applicable to other types of tumors and animal models and may be extended to humans.

Experimental studies on the flow of two immiscible fluids in porous media using X-ray computed tomography: The case when the viscosities of the fluids are equal

Experiments were carried out to demonstrate the dispersion that occurs at the interface between fluids when two immiscible fluids flow in porous structures. In this work the porous medium was cellulosic absorbent and the fluids, decyl alcohol and water, were modified so as to cover a range of flow rates and identical fluid viscosities. Computerized Tomography (CT) was used to generate dynamic three-dimensional images of two-phase saturations and provided quantitative information of time evolution of fluid saturation at each position. Thus, use of CT made characterization of two-phase displacement history in cellulosic porous media possible. This work could relate experimental fluid saturation to theoretical model of immiscible fluids flow.

Correlation of three-dimensional gradient echo dynamic MR imaging with CT during hepatic arteriography in patients with hypervascular hepatocellular carcinomas: preliminary clinical experience.

The purpose of this study is to elucidate the usefulness of dynamic MR study of the whole liver using 3DFISP with double dose gadolinium (Gd) enhancement in detecting enhancing lesions in 20 patients. Twenty patients with hepatocellular carcinoma (HCC) underwent 3DFISP dynamic study with double dose Gd. The demonstration of enhancing hypervascular lesions regardless of etiology was evaluated on a segment-by-segment basis with receiver operating characteristic (ROC) analysis, using findings on CT during hepatic arteriography as a gold standard. Diagnostic accuracy of 3DFISP in the detection of HCC was also evaluated. As to the demonstration of enhancing lesions, the Az value of the ROC curve was 88%. The detection rate of HCC with 3DFISP was 98%. 57% of enhancing pseudolesions were not detected on 3DFISP. We concluded that Dynamic MR study of the whole liver using 3DFISP with double dose Gd enhancement is a useful method to demonstrate hypervascular HCC.

Venous signal suppression in 3D dynamic Gd-enhanced carotid artery imaging using the eigenimage filter

A three-dimensional dynamic gadolinium-enhanced carotid artery imaging protocol with 10 sec per phase was evaluated with respect to the acquisition of an arterial-only phase after contrast bolus injection. Subsequently, the eigenimage filter was used to suppress any venous signal based on a difference in arterial and venous temporal enhancement patterns. From 63 consecutive scans of the carotid bifurcation, venous enhancement in the maximal arterial phase was found to be absent in 43%, weak in 19%, and strong in 38% of cases. Our eigenimage filter successfully suppressed the low signal veins in 100% and the high signal veins in 67% of cases. The number of acquired high-quality arterial-only images increased from 43% without to 87% with the use of the filter. In conclusion, even when a dynamic scan cannot resolve the short physiological delay between arterial and venous enhancement, the eigenimage filter can effectively be used to suppress the veins. Magn Reson Med 42:307-313, 1999.

Venous signal suppression in 3D dynamic Gd‐enhanced carotid artery imaging using the eigenimage filter

A three-dimensional dynamic gadolinium-enhanced carotid artery imaging protocol with 10 sec per phase was evaluated with respect to the acquisition of an arterial-only phase after contrast bolus injection. Subsequently, the eigenimage filter was used to suppress any venous signal based on a difference in arterial and venous temporal enhancement patterns. From 63 consecutive scans of the carotid bifurcation, venous enhancement in the maximal arterial phase was found to be absent in 43%, weak in 19%, and strong in 38% of cases. Our eigenimage filter successfully suppressed the low signal veins in 100% and the high signal veins in 67% of cases. The number of acquired high-quality arterial-only images increased from 43% without to 87% with the use of the filter. In conclusion, even when a dynamic scan cannot resolve the short physiological delay between arterial and venous enhancement, the eigenimage filter can effectively be used to suppress the veins. Magn Reson Med 42:307–313, 1999. © 1999 Wiley-Liss, Inc.

Venous signal suppression in 3D dynamic Gd-enhanced carotid artery imaging using the eigenimage filter.

A three-dimensional dynamic gadolinium-enhanced carotid artery imaging protocol with 10 sec per phase was evaluated with respect to the acquisition of an arterial-only phase after contrast bolus injection. Subsequently, the eigenimage filter was used to suppress any venous signal based on a difference in arterial and venous temporal enhancement patterns. From 63 consecutive scans of the carotid bifurcation, venous enhancement in the maximal arterial phase was found to be absent in 43%, weak in 19%, and strong in 38% of cases. Our eigenimage filter successfully suppressed the low signal veins in 100% and the high signal veins in 67% of cases. The number of acquired high-quality arterial-only images increased from 43% without to 87% with the use of the filter. In conclusion, even when a dynamic scan cannot resolve the short physiological delay between arterial and venous enhancement, the eigenimage filter can effectively be used to suppress the veins. Magn Reson Med 42:307-313, 1999.

Three-dimensional reconstruction of functional brain images

We consider PET (positron emission tomography) measurement with SPM (Statistical Parametric Mapping) analysis to be one of the most useful methods to identify activated areas of the brain involved in language processing. SPM is an effective analytical method that detects markedly activated areas over the whole brain. However, with the conventional presentations of these functional brain images, such as horizontal slices, three directional projection, or brain surface coloring, makes understanding and interpreting the positional relationships among various brain areas difficult. Therefore, we developed three-dimensionally reconstructed images from these functional brain images to improve the interpretation. The subjects were 12 normal volunteers. The following three types of images were constructed: 1) routine images by SPM, 2) three-dimensional static images, and 3) three-dimensional dynamic images, after PET images were analyzed by SPM during daily dialog listening. The creation of images of both the three-dimensional static and dynamic types employed the volume rendering method by VTK (The Visualization Toolkit). Since the functional brain images did not include original brain images, we synthesized SPM and MRI brain images by self-made C++ programs. The three-dimensional dynamic images were made by sequencing static images with available software. Images of both the three-dimensional static and dynamic types were processed by a personal computer system. Our newly created images showed clearer positional relationships among activated brain areas compared to the conventional method. To date, functional brain images have been employed in fields such as neurology or neurosurgery, however, these images may be useful even in the field of otorhinolaryngology, to assess hearing and speech. Exact three-dimensional images based on functional brain images are important for exact and intuitive interpretation, and may lead to new developments in brain science. Currently, the surface model is the most common method of three-dimensional display. However, the volume rendering method may be more effective for imaging regions such as the brain.

Three Dimensional Echocardiography with a Reconstructed B-Mode Image

This paper describes a three-dimensional (3D) dynamic heart imaging system. In this system, ultrasound B-mode images are measured with a transesophageal probe, a 3D heart image at a given phase of the cardiac cycle is reconstructed with a volume rendering technique and image processing and a 3D dynamic heart image is presented by displaying the 3D static images sequentially in the cardiac cycle. Furthermore, a 3D heart image is divided into two regions with a section, and a B-mode image is reconstructed and superimposed on that section. Experimental results indicate that the system enables us not only to observe the motion of the myocardium, the mitral valve and so on from any point of view but also to observe the inside structure of the heart in detail using the 3D image and the reconstructed B-mode image.

Assessment of Flail Mitral Leaflets by Dynamic Three-Dimensional Echocardiographic Imaging

To evaluate the usefulness of dynamic 3-dimensional images obtained by multiplane transesophageal echocardiography (TEE) in the diagnosis of the involved leaflets in patients with a flail mitral leaflet, 23 patients who underwent mitral valve repair were examined with multiplane TEE. In all patients, the involved lesions diagnosed by dynamic 3-dimensional images coincided with those confirmed at the time of operation; dynamic 3-dimensional images by multiplane transesophageal probe are useful in the evaluation of the involved sites in patients with a flail mitral leaflet.

A malignant phyllodes tumour imaged by three-dimensional dynamic contrast-enhanced magnetic resonance imaging

<h2>Abstract</h2> A malignant phyllodes tumour was examined pre-operatively by contrast enhanced three-dimensional dynamic magnetic resonance imaging and showed areas of fast contrast uptake corresponding to areas of malignant transformation, thus showing the malignant nature of the tumour pre-operatively.

Dynamic three-dimensional imaging of the mitral valve and left ventricle by rapid sonomicrometry array localization

Objectives. The first objective was to develop a quantitative method for tracking the three-dimensional geometry of the mitral valve. The second was to determine the complex interrelationships of various components of the mitral valve in vivo. Methods and results. Sixteen sonomicrometry transducers were placed around the mitral valve anulus, at the tips and bases of both papillary muscles, at the ventricular apex, across the ventricular epicardial short axis, and on the anterior chest wall before and during cardiopulmonary bypass in eight anesthetized sheep. Animals were studied later on 17 occasions. Reproducibility of derived chord lengths and three-dimensional coordinates from sonomicrometry array localization, longevity of transducer signals, and the dynamics of the mitral valve and left ventricle were studied. Reproducibility of distance measurements averages 1.6%; Procrustes analysis of three-dimensional arrays of coordinate locations predicts an average error of 2.2 mm. Duration of serial sonomicrometry array localization signals ranges between 60 and 151 days (mean 114 days). Sonomicrometry array localization demonstrates the saddle-shaped mitral anulus, its minimal orifice area immediately before end-diastole, and uneven, apical descent during systole. Papillary muscles shorten only 3.0 to 3.5 mm. Sonomicrometry array localization demonstrates nonuniform torsion of papillary muscle transducers around a longitudinal axis and shows rotation of papillary muscular bases toward each other during systole. Conclusion. Tagging of ventricular structures in experimental animals by sonomicrometry array localization images is highly reproducible and suitable for serial observations. In sheep the method provides unique, quantitative information regarding the interrelationship of mitral valvular and left ventricular structures throughout the cardiac cycle. (J T HORAC C ARDIOVASC S URG 1996;112:712-26)

A systematic approach to echocardiographic image acquisition and three-dimensional reconstruction with a subxiphoid rotational scan

Rotational scanning from the subxiphoid position is an image acquisition technique used for reconstruction of dynamic three-dimensional echocardiographic images in infants and small children. The orientation of the heart within the three-dimensional data set is variable and dependent on the image plane at which rotational scanning was initiated. We describe an image acquisition technique that standardizes the orientation of the heart within the three-dimensional data set, thereby permitting a systematic approach to the reconstruction of three-dimensional renderings. Thirteen infants and small children with congenital heart disease were studied by this approach. Illustrative examples are provided. The average time required to derive a three-dimensional rendering was 37 ± 9 minutes. We conclude that subxiphoid rotational scanning by a systematic approach to image acquisition and reconstruction can be applied successfully to the derivation of three-dimensional renderings of congenital cardiac defects.

Stereoscopically guided characterization of three-dimensional dynamic MR images of the breast.

A workstation was used to postprocess volume-rendered three-dimensional (3D) dynamic contrast material-enhanced magnetic resonance (MR) images of a breast carcinoma and a breast adenoma. Use of a 3D cursor allowed stereoscopic interactive probing of specific voxels to quantify contrast enhancement over time, which was mapped to a gray scale that effectively displayed enhancement as a fourth dimension. This technique is generally applicable to any time-dependent 3D imaging modality.

Dynamic three-dimensional transesophageal echocardiography using a computed tomographic imaging probe ? clinical potential and limitation

Dynamic three-dimensional echocardiography is a new diagnostic tool for spatial visualisation of cardiac anatomy and volumetric assessment. A computer-controlled probe acquires parallel tomographic slices, from which dynamic three-dimensional images of the heart can be reconstructed. Thirty adult patients with valvular heart diseases, congenital heart diseases, intracardiac masses, heart failure and other cardiac lesions, underwent conventional two-dimensional (n = 30), three-dimensional echocardiography (n = 30) and thermodilution (n = 17). The feasibility, usefulness and possibility of simulating a surgical view of intracardiac anatomy and exact volumetry were determined. The two different morphologic images were compared qualitatively. For quantitative analysis volumetry was performed using standard thermodilution technique and dynamic three-dimensional echocardiography. In more than 80% of the patients additional morphologic information was gained and a strong correlation (r = 0.75-0.95) between two volumetry assessments was found. Based on this findings, dynamic three-dimensional echocardiography is an additional and valuable approach in the perioperative and intensive care management in this group of patients.

Dynamic three-dimensional imaging with partial k-space sampling: initial application for gadolinium-enhanced rate characterization of breast lesions.

To evaluate a method to monitor gadolinium enhancement patterns at magnetic resonance (MR) imaging with high temporal resolution and full coverage through both breasts. In 12 patients with 13 masses, including nine carcinoma, nonenhanced three-dimensional MR imaging was performed with full-matrix resolution. At dynamic imaging, 32 serial passes were made during bolus administration of contrast material, and temporal resolution was reduced to 12 seconds by collecting the central (low spatial frequency) 32 x 16 or 16 x 16 phase-encode views. Full-matrix dynamic images were reconstructed by complementing central phase-encode data with precontrast data from peripheral high-spatial-frequency views. Results at time-course analysis with a mono-exponential saturation model indicated malignant lesions tend to show rapid (< 60 seconds) contrast change relative to benign masses and normal tissues. One cancer displayed an exceptionally slow contrast change (260 seconds). The technical objectives of full tissue coverage, rapid temporal sampling, and quantification of enhancement curves are met with this method for certain lesions (> 5 mm in largest diameter).

Three-Dimensional Dynamic Imaging by Spherical Pulsed Wave of Ultrasound

We developed an ultrasonic dynamic imaging system to obtain a three-dimensional echogram in a blood vessel. The method makes it possible to detect the echo signal from objects instantaneously without scanning an ultrasonic beam using a ring array probe. First, we examined the spatial resolution. Second, we performed experiments using a butter block and a copper plate. The results show that this system has a spatial resolution below 1.0 mm, and also that a butter block in a plastic tube and a moving copper plate can be detected by this system.

Delineation of site, relative size and dynamic geometry of atrial septal defects by real-time three-dimensional echocardiography

Objectives. This study attempted to determine the site, relative size and dynamioc geometry of atrial septal defects using dynamic three-dimensional echocardiography.Background. Recent studies have demonstrated the feasibility of dynamic three-dimensional echocardiography. Images are acquired from computerized reconstruction of sequential, tomographic ultrasound “slices” of the heart. Ultrasound images can be obtained by linear progression of a transducer within a transesophageal imaging probe. In small infants and children the large transducer size has not allowed transesophageal placement, and the probe has been place on the thorax or in the subcostal position. Other scaning devices, housed in plastic containers, acquire images in a rotational format and can also be placed in a transthoracic or subcostal position.Methods. Specially desiged transesophageal probes and a dedicated computer unit were used for two-dimensional image retrieval and reconstruction of three-dimensional images. Sixteen patients with atrial septal defects were studied (median age 18 months, range 1 day to 18 years). In the one patient, images were obtained by transesophageal probe placement; in the other 15 patients, the probe was placed in the transthoracic or subcostal position.Results. A dynamic three-dimensional echocardiogram of the atrial septal defect could be obtained in 13 of the 16 patients. The distinguishing features of the atrial septal defects and their spatial orientation could be visualized in unique three-dimensional views.Conclusions. Dynamic three-dimensional imaging could be applied to the specific evaluation of atrial septal defects. Unique views of the heart allowed for spatial comprehension of the defects, rendering potentially important clinical information.

Three-Dimensional Dynamic Imaging of a Human Heart Using Transesophageal Echocardiography

Three-Dimensional Dynamic Imaging of a Human Heart Using Transesophageal Echocardiography

A transputer based three-dimensional dynamic cardiac imaging system

A single-section transverse emission scanner has been adapted to trigger off patient ECG signals, allowing for the acquisition of gated blood pool tomograms at a number of slice levels through the patient's heart. The authors describe a system for the routine generation and display of surface rendered images derived from this data using a transputer based hardware system. Surface rendering algorithms have been implemented to provide an indication of the distribution of the cardiac blood pool in three dimensions, whilst the additional use of colour and/or cine sequences provide a succinct method of representing the extra information provided by gated acquisition. The transputer provides sufficient computing power to produce rendered views at a rate of about 1 frame per second, thus putting view selection fully under operator control. The success of the system described is reflected in its routine use in a busy clinical department.

Three-Dimensional Cardiac Anatomy and Function in Heart Disease in Adults: Initial Results With the Dynamic Spatial Reconstructor

The dynamic spatial reconstructor, or DSR, is a unique high-speed volume-imaging x-ray scanner based on computed tomographic principles. In this report, we present data obtained from the first feasibility DSR studies of adult patients with heart disease. Information from three patients--one with hypertrophic obstructive cardiomyopathy, one with calcific aortic valvular disease, and one with a left ventricular aneurysm--is described in detail. The mean DSR scanning time for each patient was 20 seconds, and the mean total irradiation to the sternum was 15.3 R. Transverse cross sections were reconstructed and then retrospectively reformatted to provide operator-selected oblique sections in space (for example, long-axis and short-axis sections of the left ventricle), to follow these sections through time (such as from end-diastole through end-systole), and to create three-dimensional displays (for instance, of the left ventricular chamber). Unique quantitative measurements of structure and function were made by using these images. For generation of most imaging data, only one injection of contrast material into the right side of the heart is necessary. Clinically useful three-dimensional dynamic imaging data can be acquired from adult patients with heart disease by using the DSR. Compared with conventional angiocardiography, DSR studies can provide information with less x-ray exposure and fewer angiographic injections.