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PubMed1993

High-resolution CT of the lungs.

High-resolution computed tomography (CT) of the lung provides detailed visualization of the lung parenchyma. The technique involves the use of thin-section axial tomography. High-resolution CT can facilitate the diagnosis of certain pulmonary processes. It is useful in differentiating similar patterns of abnormalities seen on chest radiographs, such as those seen in lymphangitic carcinomatosis and sarcoidosis, and in delineating the extent of co-morbid lung diseases, such as emphysema and asbestosis. In some chronic processes such as idiopathic pulmonary fibrosis, high-resolution CT can be used for biopsy of areas of active inflammation, thus increasing the diagnostic yield. As clinicians and radiologists become more familiar with high-resolution CT, it is likely that its role in the diagnosis and assessment of lung disease will increase.

Algorithms↗

PubMed1995

Ultrahigh-resolution low-voltage SEM reveals ultrastructure of the glucan network formation from fission yeast protoplast.

The refined field emission SEM, S-900 LV which gives better resolution especially at low voltages below 5 kV was developed for ultrahigh resolution scanning electron microscopy. A visualization test at x 300,000 was made using a gold-evaporated magnetic tape, and the resolution was found to be about 1 nm at 2.5 kV. The ultrastructure of the cell wall, especially the reverting glucan network, from the protoplast of Schizosaccharomyces pombe was studied using this improved ultrahigh-resolution low-voltage SEM (UHR-LVSEM). The results with uncoated reverting protoplasts observed with this microscope revealed that the network was originally formed as secreted particles scattered on the protoplast surface and these were subsequently stretched to microfibrils about 2 nm thick. The microfibrils were twisted around each other and joined together so that they developed into 8-nm-thick fibrils, forming a ribbon-shaped network of glucans about 16-nm-thick which covered the entire protoplast surface. The UHR-LVSEM images of reverting protoplasts treated with glucanase confirmed that the particles scattered on the protoplast surface in the initial stage of regeneration were glucan in nature.

Animals↗

PubMed1996

Physical and clinical evaluation of high-resolution thyroid pinhole tomography.

UNLABELLED: High-resolution pinhole-SPECT (PSPECT) is a new method for examining the thyroid gland. METHODS: The camera is tilted slightly so that it is as close to the thyroid as possible. Patients are injected with 185-260 MBq (5-7 mCi) of [99mTc]pertechnetate and examined for 20 min. The reconstruction algorithm is based on filtered back-projection. RESULTS: We performed static scintigraphy on the thyroids of 114 patients, followed by PSPECT. The major advantage of P SPECT is high resolution. Three- and 4-mm-pinholes produce resolutions of 6 mm and 7 mm, respectively, while resolutions obtained with a parallel collimator are always above 15 mm. The second advantage associated with this method is the good visualization of the cold nodules surrounded by higher activity. Finally, the reconstruction program provides exact sizes of thyroids. CONCLUSION: SPECT is a powerful tool for examining the thyroid.

Adolescent↗

PubMed1997

[The prognostic factors for early mortality and for total or partial gammagraphic resolution in venous thromboembolic disease].

Our objective was to investigate possible factors implicated in either early death from or scintigraphic resolution of pulmonary embolism. To that end we conducted a retrospective study of 116 patients with either a high likelihood of pulmonary thromboembolism (PTE) diagnosed by scintiscan or with a fair probability of PTE by scintiscan accompanied by a positive phlebograph. The images were taken upon admission, at 7 days, 10 days and 6 months. The factors analyzed were age, sex, trauma, immobility, surgery, obesity, hemiplegia, venous insufficiency, cardiopulmonary disease, neoplasia, chest X-ray and ECG alterations, D(A-a)O2 and size of perfusion defects upon admission and 7 to 10 days later. We performed single-variable analyses and multiple logical regression analyses using perfusion defect at 6 months as the dependent variable. The early mortality rate (13%) was higher in patients with neoplasms, a larger alveolar-arterial index and greater perfusion defects upon admission. Scintiscans became normal in 28%. Multivariate analysis to predict total or partial resolution at 6 months showed that size of perfusion defects at 7 to 10 days was the best predictive factor. A cutoff point was calculated by analyzing the ROC for this factor. Thus, when the defect at 7 to 10 days was equal to or greater than 1 segment, the probability of residual defects remaining after 6 months was twice as great (sensitivity 83%, specificity 57%). In conclusion, early death was more likely in PTE patients with neoplasms, larger defects upon admission and greater alveolar-arterial difference. Scintigrams showed resolution 6 months after admission in 28%. The size of perfusion defects 7 to 10 days after admission was the factor that best predicted total of partial resolution at 6 months.

Adult↗

PubMed1977

Resolution time of amoebic liver abscess by micro-opaque barium sulphate.

Resolution time of amoebic liver abscess in 20 males aged 20-80 yrs. as studied by intra-cavitary micro-opaque barium sulphate ranged from 24-284 days (mean 74.8 S.D. +/- 8.4). Sic of these patients also underwent Indium11m scanning. The resolution time by scanning varied from 24-114 days (Mean 58.3 days S.D. +/- 4.6). No correlation was found between the size of abscess and resolution time. Resolution time studied by two methods was statistically significant. Instillation of micro-opaque barium sulphate is an inexpensive, reliable and a safe method which does not require sophisticated equipment.

Adult↗

PubMed1997

[Unruptured intracranial aneurysms: evaluation with high-resolution MR angiography with magnetization transfer contrast (MTC) and tilted optimized nonsaturating excitation (TONE)].

Forty-one patients with suspected intracranial aneurysms were evaluated by conventional three-dimensional (3D) time-of-flight (TOF) MR angiography (MRA) or high-resolution 3D TOF MRA with magnetization transfer contrast (MTC) and tilted optimized nonsaturating excitation (TONE). Correlative study was done with conventional angiography in all patients. 3D TOF MRA detected 30 of 36 aneurysms depicted at conventional angiography. The overall rate of sensitivity for the detection of aneurysms was 83%. Unruptured aneurysms were unlikely to occur in the anterior communicating artery (3%), but were frequently found at the bifurcation of the middle cerebral artery (33%). Conventional MRA showed 7 of 9 aneurysms demonstrated at catheter angiography. The rate of sensitivity of conventional MRA for aneurysms smaller than 5 mm and greater than or equal to 5 mm were 0% and 100%, respectively. High resolution MRA with MTC and TONE demonstrated 23 of 27 aneurysms detected by catheter angiography. Sensitivities of high resolution MRA with MTC and TONE for aneurysms smaller than 5 mm and greater than or equal to 5 mm were 71% and 100%, respectively. Our results indicate that high-resolution 3D TOF MRA with MTC and TONE can provide precise, accurate depiction of intracranial aneurysms larger than or equal to 5 mm.

Adult↗

PubMed1998

Five-year follow-up of treated patients with glaucoma using resolution perimetry.

PURPOSE: The authors describe high-pass resolution perimetry findings during the first five years of antiglaucoma treatment. PATIENTS AND METHODS: Thirty-seven patients were examined six times, once a year for five years, with best corrected visual acuity, applanation tonometry, slitlamp examination, funduscopy, and high-pass resolution perimetry. Twenty-nine of these were treated for glaucoma and eight followed for ocular hypertension without treatment. RESULTS: The resolution thresholds in the treated group improved during the first two years and deteriorated after that back to baseline level. Regarding individual patients, the visual fields were improved in 4, unchanged in 16, and deteriorated in 13 of the 29 treated glaucoma patients at the end of the study period. CONCLUSIONS: Resolution visual fields showed initial improvement and subsequent deterioration in treated patients with early glaucoma. The conventional therapy, aiming at reducing intraocular pressure, appeared to postpone visual field decay for at least five years in about 50% of the patients.

Aged↗

PubMed1998

[High-resolution volumetric computerized tomography of the lung: optimization of technique and image quality as a function of its clinical-diagnostic use and dose to the patient].

PURPOSE: The aim of this project was to analyze and validate the diagnostic applications of Volumetric High Resolution CT in the study of focal or diffuse infiltrative lung disease compared with High Resolution CT. To date HRCT is the gold standard in the assessment of infiltrative lung diseases, but it shows some limitations such as artifacts due to both respiratory and cardiac motions, as well as the need for multiple breath-holds. MATERIAL AND METHODS: September, 1996, to September, 1997, anthropomorphic test phantoms and a group of 34 subjects (8 without lung disease and 26 with aspecific lung disease: TBC, BPCO, micronodular conditions, cardiogenic interstitial pulmonary edema) were submitted to both HRCT and VHRCT. VHRCT was carried out with a 3-mm slab thickness and the images were reconstructed with a 1-mm interval and processed with MIP and MinIP reconstructions. With both techniques we compared some physical parameters (slice sensitivity profile, noise, longitudinal resolution) and some radiographic findings (central and peripheral airways lumen, peripheral vessels, nodular and interstitial abnormalities, emphysema foci, focal areas of ground glass pattern and bronchiectasis). We calculated the radiation exposure dose of both HRCT and VHRCT, also testing a low-dose protocol. RESULTS: The analysis of physical parameters showed no major differences between HRCT and VHRCT regarding longitudinal resolution, while minimal advantages were found with HRCT for slice sensitivity profile and image noise. Radiographic analysis showed additional findings in 27% of patients with nodular disease using VHRCT-MIP in 8% of patients with emphysema and 25% of cases with focal areas of ground glass opacities, using VHRCT-MinIP. Relative to HRCT findings, VHRCT better depicted all patterns but subpleural nodules. The surface radiation dose was 2.8 times higher with VHRCT than HRCT. It is possible to halve radiation exposure using a low dose protocol (120 kV, 110-150 mA). CONCLUSIONS: Our study provides conclusive results concerning the use of VHRCT with standard technical parameters because this technique showed some advantages in the study of a wide range of diffuse or focal lung diseases. We suggest that this protocol be applied only in patients with mild forms of lung disease or in the cases of difficult interpretation, such as suspicious abnormal areas at HRCT, because its doses are higher. Out low-dose protocol is currently on trial but we expect promising results.

Evaluation Studies as Topic↗

PubMed1998

IL-4 protects adult C57BL/6 mice from prolonged Cryptosporidium parvum infection: analysis of CD4+alpha beta+IFN-gamma+ and CD4+alpha beta+IL-4+ lymphocytes in gut-associated lymphoid tissue during resolution of infection.

Resistance of adult C57BL/6 mice to severe Cryptosporidium parvum infection is dependent on CD4+alpha beta+ TCR lymphocytes. In this study, we demonstrated that treatment with anti-IFN-gamma mAb extended oocyst excretion 18 days longer, and anti-IL-4 mAb extended oocyst excretion at least 11 days longer than isotype control mAb treatment. Analysis of the specific activity of anti-IFN-gamma mAb present in treated mouse sera suggested that IFN-gamma may have a limited role in the resolution phase of infection. Changes were also documented in numbers of CD4+alpha beta+IFN-gamma+ and CD4+alpha beta+IL-4+ lymphocytes in Peyer's patches and intraepithelium of adult C57BL/6 mice during resolution of C. parvum infection. Resistance to initial severe infection was associated with CD4+alpha beta+IFN-gamma+ lymphocytes, and eventual resolution of infection was associated with CD4+alpha beta+IL-4+ lymphocytes. Analysis of cytokine expression following in vitro stimulation with C. parvum Ags during resolution of infection demonstrated consistent increases in CD4+alpha beta+IL-4+ lymphocytes, but not CD4+alpha beta+IFN-gamma+ lymphocytes. The relevance of CD4+alpha beta+IL-4+ lymphocytes in protection against C. parvum was then evaluated in C57BL/6 IL-4 gene knockout mice (IL-4(-/-)). Adult IL-4(-/-) mice excreted oocysts in feces approximately 23 days longer than IL-4(+/+) mice. Further, anti-IFN-gamma mAb treatment increased the severity and the duration of infection in IL-4(-/-) mice compared with those in IL-4(+/+) mice. Together, the data demonstrated that IFN-gamma was important in the control of severity of infection, and either IFN-gamma or IL-4 accelerated termination of infection. However, neither IL-4 nor IFN-gamma was required for the final clearance of infection from the intestinal tract of adult mice.

Age Factors↗

PubMed1996

Contribution of conventional and high resolution scanning electron microscopy and cryofracture technique to the study of cerebellar synaptic junctions.

The cerebelli of teleost fishes, primates and humans were processed for conventional and high resolution scanning electron microscopy (SEM) to study the outer and inner surfaces of axo-dendritic, glomerular and axosomatic synapses. The cryofracture technique, either by slow or fast freezing, exposed the hidden neuronal surfaces of synaptic connections, selectively removing the glial ensheathment. Axo-dendritic junctions of climbing fibers and Golgi axonal ramifications were studied in gold-palladium and chromium coated samples. Chromium coating showed different mass density and topographic contrast between axonal and dendritic profiles. Conventional SEM of cryofractured glomerular synapses exhibited the outer surface view of en passant mossy fibers glomeruli, in which granule cell dendrites appear surrounding the afferent mossy fibers. The cryo-fracture method also exposed the axosomatic contacts of basket axonal collaterals upon the Purkinje cell somatic surface and the climbing fiber bulbous endings upon tertiary Purkinje dendrites. Field emission high resolution SEM of parallel fiber-Purkinje cell dendritic spines showed the inner organization of pre-synaptic endings and the three-dimensional structure of the synaptic membrane complex. The spheroidal synaptic vesicles appeared embedded in a homogeneous axoplasmic substance. Round subunits, 15-20 nm in diameter, were observed as intrinsic components of the post-synaptic membrane and associated with the post-synaptic density. High resolution SEM offers SE-I images comparable in resolution to thin section electron microscopy and freeze-etching replicas at intermediate magnifications.

Adolescent↗

PubMed2026

HoT auto-blinking probes enable real-time, super-resolution chromatin imaging in live cells and tissues.

Single-molecule localization microscopy (SMLM) enables visualization of chromatin architecture at nanoscale resolution. However, high-performance DNA probes suitable for SMLM in both live cells and tissues remain limited. We developed Hoechst-6-Carboxytetramethylrhodamine (6-TAMRA) derivative (HoT) probes-rhodamine-based derivatives conjugated to a Hoechst moiety-through structural fine-tuning of rhodamine spirocyclization. HoTs are self-assembling, auto-blinking probes with excellent photostability and high temporal resolution. They permeate live cells, enabling long-term, real-time nanoscopic chromatin imaging in live and fixed cells and in tissue sections. In live cells, we identified nanoscale features in the 3D organization of chromatin and quantified DNA fiber kinetics at high resolution. We quantified DNA compaction in single cells within retinal and colon cancer sections. OligoSTORM (stochastic optical reconstruction microscopy)-labeled gene loci can be visualized and measured within their HoT-labeled chromatin footprints. Our work provides powerful tools for investigating chromatin structure and functions in living cells and tissues, with applications ranging from cancer diagnosis to retinal regeneration.

Chromatin↗

PubMed2002

Rate of resolution of exudative retinal detachment after plaque radiotherapy for uveal melanoma.

OBJECTIVES: To determine the clinical relevance of exudative retinal detachment (ERD) and the rate of ERD resolution after plaque radiotherapy of posterior uveal melanomas. METHODS: Retrospective, nonrandomized study of 135 consecutive patients with posterior uveal melanoma treated by iodine 125 plaque radiotherapy. Extent of ERD and tumor thickness were assessed before radiotherapy and at postoperative follow-up visits. Local tumor control was assessed at each follow-up visit. RESULTS: An ERD was present in 71 patients (53%) and was a risk factor for local treatment failure (P =.03). The ERD resolved after radiotherapy in 59 (83%) of the 71 patients. The ERD resolved within 1 year in 64 patients (90%) (mean time to resolution, 5.6 months). The rate of ERD resolution correlated with the rate of decrease in tumor thickness (P =.004). The ERD did not resolve and the tumor thickness continued to increase in 5 patients, who required further intervention. A recurrent retinal detachment developed in 5 patients, who were diagnosed as having rhegmatogenous retinal detachment (3 patients) and lipid exudation secondary to tumor vasculopathy (2 patients). Two patients with local tumor recurrence did not develop a recurrent ERD. Local tumor control was achieved in 130 patients (96%). CONCLUSIONS: An ERD may be a risk factor for local failure after plaque radiotherapy for uveal melanoma. If an ERD does not resolve within 9 to 12 months of radiotherapy and the tumor is not regressing, treatment failure should be suspected. A recurrent ERD does not necessarily represent local tumor recurrence.

Adult↗

PubMed2002

Three-dimensional high-resolution magnetic resonance imaging of ocular and orbital malignancies.

BACKGROUND: Ultrathin-section 3-dimensional fast spin-echo (3-D FSE) T2-weighted imaging is a new magnetic resonance imaging (MRI) technique that we used in the evaluation of ocular and orbital malignancies. We evaluated the usefulness of this new technique compared with conventional MRI. METHODS: Imaging data from 26 consecutive patients seen in the Ocular Oncology Unit at the University of California-San Francisco were retrospectively reviewed by physicians from the ocular oncology and neuroradiology units. For all patients, 3-D FSE T2-weighted images (27 scans) were compared with results of conventional MRI and correlated with results of computed tomography (CT), A- and B-scan ultrasonography, ultrasound biomicroscopy, clinical examinations, and histopathology, when available. RESULTS: The 3-D FSE T2-weighted imaging sequence resulted in an overall improvement in accuracy of imaging findings in 17 (63%) of our 27 cases compared with the standard MRI protocol. The increased resolution led to the radiographic detection of additional lesions in 11 (41%) of 27 cases and to an increase in confidence in radiographic diagnosis in 6 (22%) of the remaining cases. The improved resolution of the 3-D FSE T2-weighted sequence resulted in a change of disease management in 3 (60%) of the 5 patients with nonretinoblastoma lesions. One hundred percent of active retinoblastoma lesions could be detected by means of 3-D FSE and conventional imaging; however, inactive lesions were not always detected using conventional imaging. CONCLUSIONS: The 3-D FSE T2-weighted sequence offers superior resolution of intraocular and orbital structures compared with conventional MRI. It is particularly useful in the evaluation of intraocular tumors and the nerve-sheath complex. This new technique contributes significantly to improved diagnosis and management in patients with ocular and orbital malignancies.

Eye Neoplasms↗

PubMed1994

Micrometer-scale resolution imaging of the anterior eye in vivo with optical coherence tomography.

OBJECTIVE: To demonstrate a new diagnostic technique, optical coherence tomography, for high-resolution cross-sectional imaging of structures in the anterior segment of the human eye in vivo. Optical coherence tomography is a new, noninvasive, noncontact optical imaging modality that has spatial resolution superior to that of conventional clinical ultrasonography (< 20 microns) and high sensitivity (dynamic range, > 90 dB). DESIGN: Survey of intraocular structure and dimension measurements. SETTING: Laboratory. PATIENTS: Convenience sample. MAIN OUTCOME MEASURES: Correlation with range of accepted normal intraocular structure profiles and dimensions. RESULTS: Direct in vivo measurements with micrometer-scale resolution were performed of corneal thickness and surface profile (including visualization of the corneal epithelium), anterior chamber depth and angle, and iris thickness and surface profile. Dense nuclear cataracts were successfully imaged through their full thickness in a cold cataract model in calf eyes in vitro. CONCLUSIONS: Optical coherence tomography has potential as a diagnostic tool for applications in noncontact biometry, anterior chamber angle assessment, identification and monitoring of intraocular masses and tumors, and elucidation of abnormalities of the cornea, iris, and crystalline lens.

Anterior Chamber↗

PubMed1988

Correlation between high-resolution computed tomography and surgical findings in congenital aural atresia.

Congenital aural atresia poses a great challenge, even to a competent otologic surgeon, due to innumerable types of malformations affecting the conduction and perception of sound. Roentgenographic evaluation by plain roentgenography is inconclusive in most cases; polytomography is helping to some extent. Recent generations of high-resolution computed tomographic (CT) scanners are probably the best. Seven cases of unilateral and three cases of bilateral congenital aural atresia were evaluated with high-resolution CT. Subsequently, ten ears were operated on. Surgical findings were correlated with CT scan findings with respect to atresia plate, extent of pneumatization, ossicular anomalies, bony facial nerve canal, and inner ear. Use of CT scans bears considerable importance in the management of these types of cases. High-resolution CT scan, when targeted for maximal bony detail, is possibly the method of choice in congenital aural atresia when surgical correction is contemplated.

Adolescent↗

PubMed1996

Spontaneous resolution of dysgeusia.

BACKGROUND: Dysgeusia, distortion of taste perception, is a debilitating disorder that affects thousands of Americans. Presently, most forms of dysgeusia are considered to be untreatable, and no data are available for counseling patients on the probability of recovery. OBJECTIVE: To examine the probability of resolution of symptoms among patients with dysgeusia who were evaluated at the University of Pennsylvania Smell and Taste Center, Philadelphia, from January 1989 to December 1994. DESIGN: In this retrospective study, 117 patients with primary complaints of dysgeusia were initially identified from a population of 429 patients with smell and taste disorders who were seen during this period. PARTICIPANTS: Forty-eight patients agreed to participate. Each patient completed a telephone interview and a questionnaire that contained a dysgeusia severity rating scale, medical health questions, and the Beck Depression Inventory. RESULTS: Two thirds of the patients experienced spontaneous resolution of the dysgeusia, with the average duration being 10 months. A distinct relationship between the resolution of dysgeusia and depression was identified. CONCLUSION: These findings, along with the evidence that some dysgeusias are treatable, bode well for a disorder that was heretofore considered by many physicians as unrelenting.

Aged↗

PubMed2001

Medical malpractice and legal resolution systems in Japan.

Medical malpractice claims and dispute resolution systems have been examined in Western societies for their impact on the quality of care and efficient compensation for injured patients. However, little is known about the Japanese malpractice environment because claim information has been closely guarded. Based on data from the Japanese Supreme Court, the Ministry of Health, Labor, and Welfare (formerly the Ministry of Health and Welfare), and the Japan Medical Association (JMA), which provides malpractice insurance to 43.5% of Japan's 250 000 physicians, we review Japanese malpractice liability systems and the frequency of claims during the last 30 years. Annual premiums for physician professional liability insurance are relatively low (454 dollars-491 dollars). Although the frequency of claims in Japan is lower than that reported in the United States, England, and Germany, the number of claims is increasing in Japan. According to publicly available data from the Japanese Supreme Court, the annual number of medical malpractice suits filed in district courts has increased from 102 in 1970 to 629 in 1998 (from 0.09 to 0.25 per 100 physicians). The proportion of awards greater than 89 dollars 300 increased from 13.6% in 1976 to 65.4% in 1987. Among JMA members, claims increased 31% from 1987 to 1999, but the frequency of claims has remained at approximately 0.3 per 100 JMA members. The JMA's professional liability program offers a nonbinding out-of-court review of claims that is faster and less expensive than judicial resolution (a few months with no attorney required vs 35 months and attorney fees), but is a poor means of deterrence or discipline. Since JMA data represent only 43.5% of Japanese physicians, generalizations cannot be made about all Japanese physicians and institutions. The lack of data on all claims hinders adequate evaluation of dispute resolution methods, development of appropriate risk management activities, and proactive education for Japanese physicians.

Insurance, Liability↗

PubMed1996

Energy-filtered high-resolution electron microscopy and composition-sensitive imaging.

Energy-filtered electron imaging is one of the future directions of high-resolution electron microscopy (HREM). In this paper, characteristics and applications of energy-selected HREM are illustrated. Image contrast can be dramatically improved with the use of an energy filter. High-resolution chemical-sensitive imaging using ionization edge loss electrons is demonstrated in studies on Ni/Ti and A1/Ti multilayer thin films. It has been shown that the spatial resolution of energy-selected ionization edge electron images is dominated by the signal-to-noise ratio. Experimental parameters which may be selected to improve the signal-to-noise ratio are discussed. It is pointed out that since the width of the energy-selecting window is small, the energy-filtered ionization edge electron image is sensitive to the specimen composition, but the calculation of the specimen composition based on the energy-filtered images relies on the integrated ionization cross-sections which are largely determined by the solid state effects. Therefore, the energy-filtered ionization image should be referred as composition-sensitive image rather than compositional image.

Filtration↗