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PubMedDate not supplied

Confocal microscopy of stage 4 diffuse lamellar keratitis with spontaneous resolution.

PURPOSE: To report confocal microscopic findings at the onset of stage 4 diffuse lamellar keratitis and after its resolution. Stage 4 is the most severe form of diffuse lamellar keratitis. Its incidence is approximately 1 in 5000 and is associated with stromal melting, deep flap folds, central haze, hyperopic shift, irregular astigmatism, and severe decrease in visual acuity. METHODS: A 22-year-old woman underwent bilateral uncomplicated laser in situ keratomileusis (LASIK) for myopia. Postoperative course in the right eye was uneventful; however, in the left eye, stage 4 diffuse lamellar keratitis developed. Confocal microscopy examination was performed in both eyes at the onset of the syndrome and after its resolution. Findings in the eye with diffuse lamellar keratitis (left eye) were compared with the uninvolved (right) eye. RESULTS: The condition improved spontaneously and 2 years later, slit-lamp microscopy showed resolution of the folds and haze with subsequent improvement of visual acuity. However, confocal microscopic examination in the left eye revealed a persistent stromal subclinical haze on both sides of the lamellar cut and prominent folds that extended into the anterior stroma. CONCLUSION: Confocal microscopy revealed that in spite of normal appearance on slit-lamp microscopy, micromorphological alterations persisted after spontaneous resolution of stage 4 diffuse lamellar keratitis.

Adult↗

PubMed1992

[Diagnosis of ossicular chain in the middle ear by high-resolution CT].

This study was conducted to assess the usefulness and limitation of high-resolution CT for evaluating the condition of ossicular chain in the middle ear. Preoperative CT findings of the ossicular chain were compared with the operative findings of ossicles in 26 patients with chronic otitis media or congenital ossicular anomaly who underwent tympanoplasty. Total defect of head of the malleus, body of the incus and long process of the incus were completely detected by high-resolution CT. But the reliability in detecting the defect of handle of the malleus and superstructure of the stapes were 33.3% and 60%, respectively. Defect of the I-S joint (1 case) and partial defect of stapes crus (2 cases) could not be diagnosed correctly in the preoperative estimation. Although these findings demonstrate the limitations of high-resolution CT in the diagnosis of ossicular chain, it will be diminished by the advanced space resolution of CT in the future.

Ear Diseases↗

PubMed2001

Expression and regulation of Fas and Fas ligand on thyrocytes and infiltrating cells during induction and resolution of granulomatous experimental autoimmune thyroiditis.

Granulomatous experimental autoimmune thyroiditis (G-EAT) is induced by mouse thyroglobulin-sensitized spleen cells activated in vitro with mouse thyroglobulin, anti-IL-2R, and IL-12. G-EAT lesions reach maximal severity 19-21 days after cell transfer, and lesions almost completely resolve by day 35. Depletion of CD8+ cells delays resolution and reduces Fas ligand (FasL) mRNA expression in thyroids. This study was undertaken to analyze Fas and FasL protein expression in the thyroid during induction and resolution of G-EAT and to determine whether CD8+ cells might regulate Fas or FasL expression in the thyroid. Fas and FasL expression was analyzed by immunohistochemical staining or in situ hybridization in thyroids of mice with or without depletion of CD8+ cells. Fas and FasL proteins were not detectable in normal thyroids, but expression of both proteins increased during development of G-EAT. Fas was expressed primarily by inflammatory cells; some enlarged thyrocytes were also Fas+. Thyrocytes had intense FasL immunoreactvity, and many CD8+ cells were also FasL positive. Depletion of CD8+ cells resulted in decreased FasL expression by thyrocytes and inflammatory cells, but had no effect on Fas expression. TUNEL assay detected many apoptotic inflammatory cells in proximity to thyrocytes. CD8-depleted thyroids had ongoing inflammation with fewer apoptotic infiltrating cells at day 35. Administration of a neutralizing anti-FasL mAb had no apparent effects on development of G-EAT, but anti-FasL was as effective as anti-CD8 in preventing G-EAT resolution. These results suggested that CD8+ T cells and thyrocytes may kill inflammatory cells through the Fas pathway, contributing to G-EAT resolution.

Animals↗

PubMed1980

[Analysis of resolution of CNV (author's transl)].

The present study was designed to explore the factor affecting the resolution of CNV by using the paradigm in which the attention was experimentally manipulated. The control group (N=13) was given an instruction for conducting the ordinary CNV task, while the experimental group (N=26) was instructed to direct the attention to the different S2 durations. The results obtained showed that in the control group the CNV resolution occurred after the S2 onset, although in the experimental group the resolution occurred after the S2 offset. Considering the findings of this study and of Kakigi, Matsuda, and Hagino (1978) together, it was suggested that the CNV resolution was initiated by the psychological factor, not depending upon the external stimulus nor the key pressing response.

Adult↗

PubMed2006

[Study of spatial resolution in three-dimensional rotational angiography].

In interventional radiology (IVR) of cerebral aneurysms, it is important to understand the form and physical relationships between the cerebral aneurysm and the surrounding vessels. However, because the vessels in the head area are highly complex, it can be difficult to comprehend the structure using conventional angiography. Therefore, three-dimensional rotational angiography (3D-RA) has been used in recent years. This article discusses studies of the spatial resolution of 3D-RA. We reconstructed 3D-RA of an acrylic slit phantom (slit widths: 0.5, 0.75, 1.0, 1.5 mm) and examined spatial resolution by visual evaluation and profile curves. When the slit phantom was arranged to avoid the effect of beam hardening, the spatial resolution of 3D-RA was found to be as high as 0.75 mm. When the slit phantom was placed orthogonal to the rotational axis of the C-arm, the spatial resolution of 3D-RA was decreased because of the cone angle effect of X-rays. However, it was considered within the allowable range for clinical study. Consequently, 3D-RA is valuable in IVR.

Cerebral Angiography↗

PubMed2003

[Evaluation of time resolution of primary visual cortex using a single paradigm: sequence design employing a stimulation system].

The characteristics of fMRI include high-resolution, non-invasiveness, and ease of use, making it increasingly popular for brain imaging. However, imaging by the block paradigm is limited in time resolution from stimulus presentation to the subject to image acquisition. Therefore, it is not necessarily adequate for the evaluation of early (initial) brain activity. To evaluate this activity, real-time resolution during stimulation is required. We considered a single paradigm to be the most suitable for this purpose. To obtain real-time information at stimulation, it is necessary to utilize the sequence design of a single paradigm that synchronizes with an external trigger. By so doing, we found that it was possible to evaluate brain activity in the early stage in the primary visual cortex. The relative decrease of PO(2) ("sank") that was generated in the initial stage of BOLD, that is, the initial dip, was captured as a transitory change in signal by using a stimulation presentation of about two seconds in the single paradigm. Results showed that the single design provided time resolution with a high time to activation. Moreover, it is thought that imaging by a single paradigm that synchronizes with stimulation is indispensable for the time and spatial elucidation of detailed brain activity. Therefore, brain activity at the early stage in primary visual cortex was clarified by using a single paradigm that synchronized with stimulation from single-shot EPI.

Adult↗

PubMed2005

High-resolution MRI of the labyrinth: optimization of scan parameters with 3D-FSE.

The aim of our study was to optimize the parameters of high-resolution MRI of the labyrinth with a 3D-FSE sequence. We investigated TR, TE, Matrix, FOV, and coil selection in terms of CNR (contrast-to-noise ratio) and SNR (signal-to-noise ratio) by comparing axial images and/or three-dimensional images. The optimal 3D-FSE sequence parameters were as follows: 1.5 Tesla MR unit (Signa LX, GE Medical Systems), 3D-FSE sequence, dual 3-inch surface coil, acquisition time=12.08 min., TR=5000 msec, TE=300 msec, 3 NEX, FOV=12 cm, matrix=256 x 256, slice thickness=0.5 mm/0.0 sp, echo train=64, bandwidth=+/-31.5 kHz. High-resolution MRI of the labyrinth using the optimized 3D-FSE sequence parameters permits visualization of important anatomic details (such as scala tympani and scala vestibuli), making it possible to determine inner ear anomalies and the patency of cochlear turns. To obtain excellent heavily T2-weighted axial and three-dimensional images in the labyrinth, high CNR, SNR, and spatial resolution are significant factors at the present time. Furthermore, it is important not only to optimize the scan parameters of 3D-FSE but also to select an appropriate coil for high-resolution MRI of the labyrinth.

Ear, Inner↗

PubMed1983

Particle image-resolution test object.

A blur definition and measurement technique for high-subject-contrast image resolution is proposed. A new test object utilizing the blur principle has been developed and feasibility tested. In developing this new test object, tests of various sizes and concentrations of small plastic particles in a gelatin base were performed. Optimum particle sizes and concentrations were selected for the popular clinical transducer frequencies. Test images were obtained with static and real-time transducers of various focal properties. In all cases the proposed test object clearly indicated the zone (focal zone) of optimum high-subject-contrast image resolution. The advantages of the proposed blur definition and measurement technique of high-subject-contrast image resolution include: test object simplicity, ease of performing and interpreting the measurement, usefulness for all types of real-time scanners, and the need for only one scan for both axial and lateral resolution information at all image depths.

Equipment and Supplies↗

PubMed1999

Structure and function of chromophores in R-Phycoerythrin at 1.9 A resolution.

The crystal structure of R-Phycoerythrin (R-PE) from Polysiphonia urceolata has been refined to a resolution of 1.9 A, based on the atomic coordinates of R-PE determined at 2.8 A resolution, through the use of difference Fourier method and steorochemistry parameters restrained refinement with model adjustment according to the electron density map. Crystallographic R-factor of the refined model is 0.195 (Rfree = 0.282) from 8-1.9 A. High resolution structure of R-PE showed precise interactions between the chromophores and protein residues, which explained the spectrum characteristic and function of chromophores. Four chiral atoms of phycourobilin (PUB) were identified as C(4)-S, C(16)-S, C(21)-S, and C(20)-R. In addition to the coupling distances of 19 A to 45 A between the chromophores which were observed and involved in the energy transfer pathway, high resolution structure of R-PE suggested other pathways of energy transfer, such as the ultrashort distance between alpha140a and beta155. It has been proposed that aromatic residues in linker proteins not only influence the conformation of chromophore, but may also bridge chromophores to improve the energy transfer efficiency.

Amino Acid Sequence↗

PubMed2000

High-resolution MR imaging of the carpal tunnel and the wrist. Application of a 5-cm surface coil.

PURPOSE: To make a comparative analysis of transversal tomograms obtained by high-resolution MR imaging with frozen cross-sections of an anatomical forearm specimen. Twenty-two healthy volunteers were also examined using the same coil system to test for a range of possible clinical applications and for the depiction of morphological and morphometrical values of normal anatomy in vivo. MATERIAL AND METHODS: MR images of the carpal tunnel of 22 healthy volunteers were obtained with a 1.5-T whole-body system with a 5-cm surface coil. Measurements were recorded with a field-of-view between 50x50 mm2 and 60x60 mm2 in a 256x256 pixel matrix for the T1 sequence. A slice thickness of 2 mm was used. The images were acquired using a T1-weighted SE sequence (TR/TE 500/38 ms) and a T2-weighted SE sequence (TR/TE 2000/70 ms). Additionally, a formalin-fixed anatomical forearm specimen was imaged for anatomic correlation. The imaged transversal cross-section levels in the specimen were subsequently freeze-sectioned. The anatomical structures of the MR findings were identified and compared with the macroscopical sections of the specimen. RESULTS: Based on the good depiction of details at this coil system with a pixel size in T1 of 0.195x0.195 mm, high-resolution MR imaging enabled identification of the interior structures of the carpal tunnel, as well as delineation of connective tissue. The clinical value of high-resolution MR includes the diagnosis of carpal tunnel syndrome and inflammatory disorders of the wrist. CONCLUSION: Our results support the feasibility of high-resolution MR imaging of the carpal tunnel and the wrist using small surface coils.

Carpal Bones↗

PubMed2000

[Investigation of the resolution and count recovery coefficients of a whole-body PET scanner (Shimadzu SET-2400W) in 2D and 3D mode image].

UNLABELLED: We measured the resolution and count recovery coefficients (RC) of the SET-2400W whole-body PET scanner (Shimadzu Co., Japan) in the 2D and 3D clinical modes. METHOD: The 3D images were reconstructed by using the full 3D image reconstruction method (3-D reprojection algorithm: 3DRP) and the Fourier rebinning method (FORE). The 2D images were reconstructed with conventional filtered back-projection method (FBP). The measurements of resolution and recovery coefficient were according to JRIA (Japan Radioisotope Association) protocols. RESULTS: The transaxial resolutions of all methods were better than 7 mm FWHM at a radius of 10 cm with 1.25 cm-1 cutoff frequency. The average slice width of 2D FBP, 3DRP and FORE are 5.8 mm, 8.0 mm and 6.8 mm respectively at the center of transaxial field of view. The RC values were measured in a range from 10 mm to 27 mm at 6 cm from the center with the cylindrical and spherical hot area phantoms. In all methods, RC values at 27 mm diameter were nearly 1.0 in both type of hot area. RC values at 10 mm diameter in 2D FBP, 3DRP and FORE of cylindrical hot area were 0.69, 0.72, 0.73 and those of spherical hot area were 0.52, 0.51, 0.53 respectively. CONCLUSION: At the SET-2400W, resolution and recovery coefficient of 3D mode image under the clinical mode showed the value which did not differ from the 2D mode image.

Image Processing, Computer-Assisted↗

PubMed1997

Permanent Electronic Storage of Angiographic Images in the Catheterization Laboratory: High-Resolution and Real-Time Acquisition on Optical Laserdiscs.

The use of electronic ÒfilmlessÓ media for long-term archiving of coronary angiograms has been impeded by the problems of image storage and data transfer among institutions. Although long-term analogue storage of the images is presently feasible, and much less costly than digital storage, processing has been limited to a 625 lines video format, not optimal for high quality images. We developed a bi-directional 1249/625 lines converter, able to store and to replay high resolution (1249 lines) video images, from Component Record Video (CRV) Optical Laser (Analogue) Videodisks. Image quality and medical relevance were evaluated five ways: 1) Outside experts compared 593 static images stored on CRV discs to the same images stored in a high-resolution digital format blinded to source of image. The four experts found no visual or medical difference in 98% of evaluated images and minor differences in the remainder. The differences in the remaining images were not consistent among experts. 2) Two of the experts also compared the enhanced CRV optically stored image to the image obtained on simultaneously recorded 35mm cine film, and found the enhanced CRV stored image to be superior or similar, but never inferior to the film image. 3) 90 representatives from 63 outside institutions compared images from both a digital hard drive and the enhanced CRV optical (analogue) storage displayed at a Windows based digital workstation. During the test they were blinded as to the source of the images. The representatives found no difference in image resolution, quality, diagnostic accuracy, and medical relevance. 4) We evaluated quantitative coronary angiography (QCA) on standard coronary test phantoms using enhanced CRV stored images digitally processed. The correlation of the enhanced CRV image to the actual size of the phantom vessels was similar to the results obtained in the literature from digitally stored images. 5) 78 arterial measurements ranging 0.65 to 4.85 mm were evaluated both from the digital hard disc (D) and the CRV optical disc (CRV), using the same QCA analytical package. The correlation coefficient and the Standard Error of the Estimate between D and CRV values were respectively 0.997 and 0.076, no systematic over or underestimation occurred, and the mean variability was inferior to 0.1 mm. CONCLUSION: High-Resolution CRV-optical storage represents a cost-effective solution for excellent image quality equivalent to digitally stored images, permitting permanent electronic archiving inside the cath-lab, and allowing digital image processing and digital image communication.

Journal Article↗

PubMed2000

High resolution MRI of adrenal glands in patients with primary aldosteronism.

BACKGROUND: We studied the role of high-resolution magnetic resonance imaging (MRI) of the adrenal glands using a surface coil in patients with primary aldosteronism to differentiate aldosterone-producing adenomas (APA) from idiopathic hyperplasia of the adrenal gland (IHA). The data obtained were used to decide on surgical or nonsurgical treatment for patients. METHODS: High-resolution MRI with SE T1WI, FSE T2WI and paired in- and out-phase images of the adrenal glands of 41 patients with clinically documented primary aldosteronism were collected. The images were reviewed in comparison with other differentiating tests. RESULTS: Nineteen of the 41 patients were diagnosed with APA on MRI. Surgical and pathologic proof of APA was obtained in 10 cases and solitary macronodular hyperplasia was found in one case. Among these 11 cases, there were no false positive findings on MRI, while correct detectability of high-resolution computerized tomography (CT) was 62.5% (5/8); for adrenal venous sampling, it was 37.5% (3/8); and for NP-59 adrenal scanning, it was 42.9% (3/7). In eight cases with biochemically favored APA and no surgical proof, MRI and CT showed the same lesion detection rate, while there was no concordance with venous sampling, and concordance of only 33.3% (2/6) for adrenal scanning. In the remaining 22 patients without focal lesions on MRI, there was poor concordance among the four test modalities, with frequently conflicting results. CONCLUSIONS: In patients with definitive results of noninvasive biochemical tests for APA, and positive findings of unilateral, focal adrenal lesion on MRI or CT, unilateral adrenalectomy may be justified without further tedious and invasive examinations. CT should still be the first screening test; however, high-resolution MRI is a useful diagnostic supplement for patients with strong clinical evidence of APA and negative or equivocal findings on CT.

Adrenal Glands↗

PubMed2000

Resolution of urge symptoms following sling cystourethropexy.

PURPOSE: Persistence of urinary urge symptoms in women after pubovaginal sling cystourethropexy is a distressing problem. We assess the ability of preoperative video urodynamics to identify patients in whom urinary urge symptoms failed to resolve postoperatively. MATERIALS AND METHODS: The records of 84 consecutive women who had undergone pubovaginal sling cystourethropexy were reviewed. Preoperative video urodynamics revealed stress urinary incontinence in all cases and concomitant detrusor instability in some. Cases of motor urge, defined as urge symptoms plus detrusor instability, were divided into low and high pressure categories. Patients with urge symptoms but no demonstrable detrusor instability on video urodynamics were diagnosed with sensory urge. Postoperatively complete urge resolution was defined as total absence of symptoms without pharmacological therapy. Mean followup was 26.7 months (range 2 to 62). RESULTS: Of the 84 patients 41 with motor urge and 28 with sensory urge had preoperative urge symptoms. Complete resolution or improvement in urge symptoms occurred in 24 (58.5%) and 7 (17.1%) of the motor urge, and 11 (39.3%) and 9 (32.1%) of sensory urge cases, respectively. Of the 41 patients with motor urge 23 had low pressure instability, which completely resolved in 21 (91.3%) and improved in 2 (8.7%). Of the 18 remaining patients with high pressure motor urge only 5 (27. 8%) had complete resolution of urge and 5 (27.8%) had improvement. CONCLUSIONS: Our results suggest that patients with low pressure motor urge are significantly more likely to experience resolution of urinary urge symptoms after pubovaginal sling cystourethropexy than those with high pressure motor urge or sensory urge.

Female↗

PubMed2001

Evaluation of capillary electrophoresis performance through resolution measurements.

The application of resolution measurements to an electrophoretic system can give a quantitative analysis of the health of that system. Capillary electrophoresis has become a routine method for the analysis of DNA and resolution measurements can be used to assess the resulting electropherogram. A number of methods are available to evaluate resolution and three methods are detailed in the current work. Parameters such as polymer concentration and column length were also examined in terms of resolution, and changes therein, if these parameters were modified.

DNA↗

PubMed2001

[Multi-resolution blending rendering of the medical structure].

This paper presents a new medical data visualization method called multi-resolution blending rendering which has been developed for visualizing the large medical volume data sets. Different from those multi-resolution rendering methods which simplify the structures by polygon mesh optimization technique, the new method uses different resolution levels to represent different parts of a structure at the same time. So, it can preserve the integrality of the structure and emphasize the important part of the structure when simplifying the structure. The new method also takes advantage of the good qualities of the wavelet transform and constructs the multi-resolution blending model of the structure by orthogonal wavelet transform and transition operator. The experiment proves that our method can effectively simplify the model of the structure, enormously reduce the number of the triangle of the structure and speed up the structure rendering. It is especially suitable for interactive observations on a complex medical structure.

Algorithms↗

PubMed2001

Tactile discrimination of edge shape: limits on spatial resolution imposed by parameters of the peripheral neural population.

When the flat faces of a coin are grasped between thumb and index finger, a "curved edge" is felt. Analogous curved edges were generated by our stimuli, which comprised the flat face of segments of annuli applied passively to immobilized fingers. Humans could scale the curvature of the annulus and could discriminate changes in curvature of approximately 20 m(-1). The responses of single slowly adapting type I afferents (SAIs) recorded in anesthetized monkeys could be quantified by the product of two factors: their sensitivity and a spatial profile dependent only on the radius of the annulus. This allowed us to reconstruct realistic SAI population responses that included noise, variation in fiber sensitivity, and varying innervation patterns. The critical question was how relatively small populations ( approximately 70 active fibers) can encode edge curvature with such precision. A template-matching approach was used to establish the accuracy of edge representation in the population. The known large interfiber variability in sensitivity had no effect on curvature resolution. Neural resolution was superior to human performance until large levels of central noise were present showing that, unlike simple detection, spatial processing is limited centrally. In contrast to the behavior of mean response codes, neural resolution improved with increasing covariance in noise. Surprisingly, resolution for any single population varied considerably with small changes in the position of the stimulus relative to the SAI matrix. Overall innervation density was not as critical as the spacing of receptive fields at right angles to the edge.

Adult↗

PubMed2001

Multivoxel 3D proton spectroscopy in the brain at 1.5 versus 3.0 T: signal-to-noise ratio and resolution comparison.

BACKGROUND AND PURPOSE: The new 3.0-T imagers theoretically yield double the signal-to-noise ratio (SNR) and spectral resolution of 1.5-T instruments. To assess the possible improvements for multivoxel 3D proton MR spectroscopy (1H-MRS) in the human brain, we compared the SNR and spectral resolution performance with both field strengths. METHODS: Three-dimensional 1H-MRS was performed in four 21-29-year-old subjects at 1.5 and 3.0 T. In each, a volume of interest of 9 x 9 x 3 cm was obtained within a field of view of 16 x 16 x 3 cm that was partitioned into four (0.75-cm-thick) 16 x 16-voxel sections, yielding 324 (0.75-cm3) signal voxels per examination. RESULTS: In an acquisition protocol of approximately 27 min, average voxel SNRs increased 23-46% at 3.0 versus 1.5 T in the same brain regions of the same subjects. SNRs for N-acetylaspartate, creatine, and choline, respectively, were as follows: 15.3 +/- 4, 8.2 +/- 2.2, and 8.0 +/- 2.0 at 1.5 T and 22.4 +/- 7.0, 10.1 +/- 3.5, and 10.1 +/- 3.6 at 3.0 T. Spectral resolution (metabolite linewidths) were 3.5 +/- 0.5 Hz at 1.5 T versus 6.1 +/- 1.5 Hz at 3.0 T in approximately 900 voxels. Spectral baselines were noticeably flatter at 3.0 T. CONCLUSION: Expected gains in SNR and spectral resolution were not fully realized in a realistic experiment because of intrinsic and controllable factors. However, the 23-46% improvements obtained enable more reliable peak-area estimation and an 1H-MRS acquisition approximately 50% shorter at 3.0 versus 1.5 T.

Adult↗