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Results for “Visible Human Projects”

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PubMed2006

Intracranial 2D and 3D DSA with flat panel detector of the direct conversion type: initial experience.

The purpose of this study was to compare the image quality of two-dimensional (2D) digital subtraction angiography (DSA) between a flat panel detector (FPD) of the direct conversion type with low radiation dose and a conventional image intensifier (I.I.)-TV system, and to assess 3D DSA with the FPD system in the depiction of intracranial vessels. Fifteen consecutive patients (five men, ten women; age range: 18-82 years; mean age: 55.5 years) were prospectively included in this study. All patients underwent 2D DSA with both the FPD and I.I.-TV system in one projection. The radiation doses during angiography were evaluated using a phantom. The 3D DSA images were created from the rotational DSA data with the FPD system. Two blinded radiologists independently evaluated 2D DSA with the FPD system and I.I.-TV system using a 5-point assessment scale (excellent to not visible) to assess the depiction of intracranial vessels. MIP and volume rendering (VR) images of 3D DSA with the FPD system were also evaluated using a 5-point scale (excellent to not visible). DSA and fluoroscopy dose measurements with the phantom showed a dose reduction of approximately 85% and 9% with the FPD system compared with the I.I.-TV system, respectively. For 2D DSA, the FPD system was significantly superior to the I.I.-TV system with respect to the visibility of the peripheral and perforating vessels (p<0.05). The peripheral and perforating vessels were also sufficiently visualized on MIP images of 3D DSA in all 15 cases. Our FPD system was found to be superior to the I.I.-TV system in visualizing small intracranial vessels combined with a significant reduction of radiation dose, and was able to create high-quality 3D DSA images on which high spatial resolution allowed precise visualization of small vessels such as perforating ones.

Adolescent↗

PubMed2006

View-independent reconstruction algorithms for cone beam CT with general saddle trajectory.

In Yang et al (2006 Phys. Med. Biol. 51 1157-72), an exact filtered backprojection (FBP) reconstruction algorithm was proposed for cone beam tomography with saddle trajectory based on the seminal works of Pack and Noo (2005a Inverse Problems 21 1105-20; 2005b 8th Int. Meeting on Fully 3D Reconstruction in Radiology and Nuclear Medicine (Salt Lake City) ed F Noo, H Kudo and L G Zeng pp 287-90). However, the artefacts due to discretization and/or sampling errors in the reconstructed images by this method were still visible, especially when the pitch is large. In this paper, two view-independent (VI) algorithms, which are similar to the FDK-type algorithms (Feldkamp et al 1984 J. Opt. Soc. Am. A 1 612-19), are proposed for planar detector geometry. The first VI algorithm involves two filtered projections and a small additional term (two-dimensional (2D) Radon transform term). One of the filtered projections is obtained by ramp filtering (as in the FDK algorithm for circular trajectory) and the other one is obtained by Hilbert transform. The 2D Radon transform term is just like the term which was first derived by Hu (1996 Scanning 18 572-81) for a circular trajectory. The second VI algorithm involves only one filtered projection term, which is obtained by differentiation followed by Hilbert transform and the 2D Radon transform term. Both algorithms involve only one backprojection step with a weighting factor as in the FDK algorithm. The simulation studies show that the pixel values of the reconstructed images by the VI algorithms are more accurate than those by the original view differencing (VD) algorithm, the streak artefacts are also reduced, and their computational times are comparable to that of the original VD algorithm. We also generalize the concept of saddle trajectory and the corresponding reconstruction algorithm. The generalized algorithm is also theoretically exact, has a shift-invariant FBP structure, and does not depend on the concept of pi-line.

Algorithms↗

PubMed1998

Technetium-99m-labeled HL91 to identify tumor hypoxia: correlation with fluorine-18-FDG.

UNLABELLED: Technetium-99m HL91 is a potential agent for imaging hypoxic tissue in vivo. A pilot evaluation using a prototype formulation assessed efficacy in tumor imaging and compared results with 18F-fluorodeoxyglucose (FDG) PET. METHODS: Ten patients with malignant tumors were included. Tumors included carcinoma of the bronchus (n = 3), carcinoma of the thyroid (n = 2), lymphoma (n = 2), soft tissue sarcoma (n = 1), carcinoid (n = 1) and carcinoma of the breast (n = 1). Whole-body planar scans and localized SPECT scans were performed at 1 and 4 hr postinjection of 600 MBq 99mTc HL91. Half-body and localized emission/transmission 18F-FDG PET scans were performed 60 min postinjection 370 MBq 18F-FDG in eight patients. Lesion-to-normal tissue background ratios were measured for all 99mTc HL91 and 18F-FDG PET scans and percentage uptake and standardized uptake values measured for 99mTc HL91 and 18F-FDG PET, respectively. RESULTS: Technetium-99m HL91 showed visible uptake into the tumor area in all seven studies where the tumor was clearly identified by 18F-FDG PET; 99mTc HL91 uptake was not detected in one study (carcinoid) in which 18F-FDG was weakly positive. Two further tumors, in which PET correlation was not available, showed accumulation of 99mTc HL91. In two 99mTc HL91 studies, abnormality was apparent only on SPECT images. Lesion-to-normal tissue background ratios for 99mTc HL91 ranged from 1.22/2.53 at 1 hr and 1.33/2.89 at 4 hr on planar images and 1.23/5.2 and 1.67/14.6 on SPECT images, respectively. CONCLUSION: In this study, the use of 99mTc HL91 resulted in uptake in the majority of malignant tumors identified by 18F-FDG-PET. Technetium-99m HL91 exhibits good imaging characteristics, with imaging at 4 hr providing good lesion-to-normal tissue background ratios, that are further enhanced by SPECT.

Aged↗

PubMed2003

Subthalamic nucleus deep brain stimulation for Parkinson's disease: magnetic resonance imaging targeting using visible anatomical landmarks.

BACKGROUND: The aim of the present study was to validate a magnetic resonance imaging (MRI) visual procedure to target the subthalamic nucleus (STN) based on surrounding anatomical landmarks. METHODS: 31 consecutive bilaterally implanted parkinsonian patients were included in this study. After identification of the anterior commissure (AC), posterior commissure (PC) and midcommissural point on a three-dimensional T1-weighted sequence, inversion recovery (IR) T2-weighted coronal slices were performed orthogonal to the AC-PC line. On the slice showing the anterior pole of the red nucleus (RN), the target was placed in the inferolateral portion of the subthalamic zone, limited superiorly by the thalamus, laterally by the internal capsule, inferiorly by the substantia nigra and medially by the midline. The distribution of the targets was analyzed in the AC-PC referential. RESULTS: The mean target coordinates were as follows: anteroposterior (AP) = -2.54 mm (+/-1.37 mm), lateral (LAT) = 12.03 mm (+/-0.91 mm) and vertical (VERT) = -6.10 mm (+/-1.52 mm) for the right side, and AP = -2.65 mm (+/-1.36 mm), LAT = -11.97 mm (+/-1.30 mm) and VERT = -5.89 mm (+/-1.52 mm) for the left side. They projected in the inferior portion of the STN on the Schaltenbrand and Wahren atlas [Stuttgart, Thieme, 1977]. CONCLUSION: Identification of the anterior pole of the RN and the subthalamic zone on coronal IR T2-weighted MRI performed orthogonal to the AC-PC line provides a precise visual procedure to target the STN.

Electric Stimulation Therapy↗

PubMed1995

Automated localization of the prostate at the time of treatment using implanted radiopaque markers: technical feasibility.

PURPOSE: Prostate movement is a major consideration in the formation of target volumes for conformal radiation therapy of prostate cancer. The goal of this study was to determine the technical feasibility of using implanted radiopaque markers and digital imaging to localize the prostate at the time of treatment, thus allowing for reduction of the margin required for uncertainty in target position. METHODS AND MATERIALS: Radiopaque markers implanted around the prostate prior to treatment are visible on electronic radiographs generated with a portal imager or diagnostic imaging device. The locations of the images of these markers on the digital radiographs were automatically determined by a template-matching algorithm. The coordinates of the markers were found by projecting rays through the marker locations on orthogonal radiographs using a three-dimensional (3D) point-matching algorithm. Prostate and/or patient movement was inferred from the marker displacements. Images generated from known movements of a phantom with implanted markers were tested with this algorithm. Locations of markers from daily images of patients with implanted markers were determined by both manual and automatic techniques to determine the efficacy of automated localization on typical clinical images. RESULTS: Prostate movements can be automatically detected in a phantom using low-energy photons within 30 s after image acquisition and with a precision of better than 1 mm in translation and 1 degree in rotation (indistinguishable from the uncertainty in measuring precision). CONCLUSION: The studies show that on-line repositioning of the patient based on localization of the markers at the time of treatment is feasible, and may reduce the uncertainty in prostate location when combined with practical on-line repositioning techniques.

Feasibility Studies↗

PubMed1995

3-D shape perception.

In this paper, we analyze and test three theories of 3-D shape perception: (1) Helmholtizian theory, which assumes that perception of the shape of an object involves reconstructing Euclidean structure of the object (up to size scaling) from the object's retinal image after taking into account the object's orientation relative to the observer, (2) Gibsonian theory, which assumes that shape perception involves invariants (projective or affine) computed directly from the object's retinal image, and (3) perspective invariants theory, which assumes that shape perception involves a new kind of invariants of perspective transformation. Predictions of these three theories were tested in four experiments. In the first experiment, we showed that reliable discrimination between a perspective and nonperspective image of a random polygon is possible even when information only about the contour of the image is present. In the second experiment, we showed that discrimination performance did not benefit from the presence of a textured surface, providing information about the 3-D orientation of the polygon, and that the subjects could not reliably discriminate between the 3-D orientation of textured surface and that of a shape. In the third experiment, we compared discrimination for solid shapes that either had flat contours (cuboids) or did not have visible flat contours (cylinders). The discrimination was very reliable in the case of cuboids but not in the case of cylinders. In the fourth experiment, we tested the effectiveness of planar motion in perception of distances and showed that the discrimination threshold was large and similar to thresholds when other cues to 3-D orientation were used. All these results support perspective invariants as a model of 3-D shape perception.

Attention↗

PubMed1998

Bioengineering in the millennium.

This symposium identified the major challenges in biomedical research that will benefit from bioengineering applications. Attention was focused on the important role that bioengineers will play in future advances in biomedical research. There was considerable discussion about how to integrate bioengineering with biological research in meeting the challenges of the twenty-first century. Symposium presenters showcased the accomplishments of NIH-funded bioengineering researches and increased the visibility of bioengineering to NIH leaders, staff, and members of the intramural and extramural research community. Recommendations were also made for future NIH-funded research projects. Attention was also placed on how basic bioengineering research can lead to commercialization of new health care technology and therefore maintain the nation's leadership in this important area. New products, from biotechnology and novel devices for diagnosis and treatment, are marketed through interactions between universities, medical centers, small start-up firms, and larger, more established companies. In the United States the gross revenue of the bioengineering private sector industry involved in the manufacture of health care products already exceeds $40 billion. More then 750 persons attended this bioengineering symposium. Over 110 scientific posters and exhibits relating to biology and medicine were presented. They provided a forum for showcasing NIH-funded bioengineering projects and fostered future collaboration among academic investigators, industry, and members of the small business community. The contributions of Pugwash bioengineer, Maciej Natecz, a member of the Polish Academy of Sciences, was recognized by the Conference Planning Committee. He was honored for his work in nuclear disarmament. Indian medical scientists should note that this symposium provided a framework for the development of technology in biomedical sciences during the Twenty-First Century. Major concentrations in interdisciplinary research should occur at all of the premier research institutions in India.

Animals↗

PubMed2006

Initial development of a device for controlling manually applied forces.

UNLABELLED: In both simulation and manual therapy studies, substantial variability has been shown when therapists attempt to replicate an applied force. Knowledge about the forces employed during treatment could reduce this variability. In the current project, a prototype for a mobilizing device incorporating a dynamometer was constructed. The prototype device was built around a conventional "hand-grip" dynamometer to give dial visibility during application of mobilizing forces and a moulded handle was used to increase the hand contact surface during force application. The variability of the mobilization forces produced was measured, and ratings of comfort during a simulated spinal mobilization technique were obtained from therapists. METHOD: Thirty physiotherapists were randomly allocated to apply either: (i) their own estimate of a grade III mobilization force using their hands in a pisiform grip or (ii) a 100N force with the manual therapy dynamometer, and to rate comfort during the performance of both techniques on a 100mm visual analogue scale. RESULTS: Variance in dynamometer-dial-guided force application was always significantly less than the variance in therapist-concept-guided force application. Repeated-measures tests showed that the mean force produced at grade III was not significantly different from 100N, but physiotherapist comfort ratings were found to be significantly greater (P<0.01) when the manual therapy dynamometer was used. CONCLUSION: Manually applied force variability was significantly less and therapist comfort greater when using a device with visual access to a dial giving immediate force readout.

Adult↗

PubMed1996

The sternalis muscle: an unusual normal finding seen on mammography.

OBJECTIVE: We studied the appearance of the sternalis muscle on mammography and on CT and MR imaging. To our knowledge, this is the first description of this normal anatomic variant. An approach is provided that permits differentiation of the sternalis from significant pathology. SUBJECTS AND METHODS: Between January 1992 and December 1994, four women of an estimated 32,000 who had mammograms at the Massachusetts General Hospital had an unusual, irregular structure visible medially on the craniocaudal projection that posed a diagnostic dilemma. The records and imaging studies of these women and two others from the Deaconess Hospital breast imaging program were reviewed to determine the etiology of the findings seen by mammography and to establish a diagnostic approach. RESULTS: Surgery in one patient and cross-sectional imaging in the other five established that the structure was the sternalis muscle. Although it may be bilateral, the sternalis muscle was visible only unilaterally on the mammograms of these six women. The appearance of the muscle ranged from an irregularly rounded density at the sternal edge of the film to flame-shaped and almost completely surrounded by fat. CT and MR imaging are diagnostic when they show the longitudinal extent of the muscle, which lies anterior to the medial margin of the pectoralis major muscle. CONCLUSION: The sternalis muscle is an unusual variant of the chest wall musculature. It may be visible as a rounded or irregular density on the craniocaudal mammogram along the sternal edge of the film. With improved mammographic positioning it will be seen more frequently. The muscle has a variety of appearances that should be familiar to the radiologist to avoid confusion with a malignant lesion. The etiology can be confirmed and cancer excluded by CT or MR imaging.

Adult↗

PubMed2000

Transpulmonary contrast echocardiography: effects on delineation of endocardial border, assessment of wall motion and interobserver variability in stress echocardiograms of limited image quality.

BACKGROUND: A major limitation of stress echocardiography remains poor image quality. OBJECTIVE: To investigate the effects of transpulmonary contrast echocardiography (TCE) with BY 963 on endocardial border delineation, detectability of wall motion abnormalities and interobserver variability at rest and during dobutamine stress echocardiography (DSE) in subjects with technically limited baseline echocardiograms. METHODS: BY 963 was administered intravenously to 36 patients (5 ml for parasternal LAX/SAX, 10 ml for apical four-chamber/two-chamber view) both at rest and at peak stress during DSE. Two observers applied a delineation score (0, endocardial border not visible; 1 border poorly visible; and 2, border clearly visible) to 12 wall segments in the parasternal and 10 in the apical views both before and after administration of BY 963. A 16-segment wall-motion score was used. RESULTS: In parasternal views, the delineation score was not improved by TCE. In the apical views, TCE significantly increased the delineation score (from 14.1 +/- 5.4 to 20.7 +/- 4.2 at rest and from 14.6 +/- 5.7 to 21.7 +/- 4.1 under stress, both P< 0.01). For 18 of 25 patients with coronary artery disease (> or = 70% stenosis) results of DSE were positive before TCE, whereas results were positive for 21 patients during TCE. For 10 of 11 patients without coronary artery disease, results of DSE were negative both before and during TCE. For the apical delineation score, interobserver variability was decreased significantly by TCE (from 19.5 +/- 19.6 to 8.2 +/- 15.6% at rest and from 20.2 +/- 19.6 to 3.3 +/- 11.4% at peak stress, both P< 0.01). CONCLUSIONS: TCE enhances endocardial border delineation in apical views at rest and during DSE, resulting in a decrease of interobserver variability and an improvement in assessment of wall motion. Use of TCE, at least how it was applied in this investigation, seems not to be indicated for parasternal projections.

Cardiotonic Agents↗

PubMed2004

Communication failures in the operating room: an observational classification of recurrent types and effects.

BACKGROUND: Ineffective team communication is frequently at the root of medical error. The objective of this study was to describe the characteristics of communication failures in the operating room (OR) and to classify their effects. This study was part of a larger project to develop a team checklist to improve communication in the OR. METHODS: Trained observers recorded 90 hours of observation during 48 surgical procedures. Ninety four team members participated from anesthesia (16 staff, 6 fellows, 3 residents), surgery (14 staff, 8 fellows, 13 residents, 3 clerks), and nursing (31 staff). Field notes recording procedurally relevant communication events were analysed using a framework which considered the content, audience, purpose, and occasion of a communication exchange. A communication failure was defined as an event that was flawed in one or more of these dimensions. RESULTS: 421 communication events were noted, of which 129 were categorized as communication failures. Failure types included "occasion" (45.7% of instances) where timing was poor; "content" (35.7%) where information was missing or inaccurate, "purpose" (24.0%) where issues were not resolved, and "audience" (20.9%) where key individuals were excluded. 36.4% of failures resulted in visible effects on system processes including inefficiency, team tension, resource waste, workaround, delay, patient inconvenience and procedural error. CONCLUSION: Communication failures in the OR exhibited a common set of problems. They occurred in approximately 30% of team exchanges and a third of these resulted in effects which jeopardized patient safety by increasing cognitive load, interrupting routine, and increasing tension in the OR.

Anesthesia Department, Hospital↗

PubMed2005

An adaptive approach to metal artifact reduction in helical computed tomography for radiation therapy treatment planning: experimental and clinical studies.

PURPOSE: In this article, an approach to metal artifact reduction is proposed that is practical for clinical use in radiation therapy. It is based on a new interpolation scheme of the projections associated with metal implants in helical computed tomography (CT) scanners. METHODS AND MATERIALS: A three-step approach was developed consisting of an automatic algorithm for metal implant detection, a correction algorithm for helical projections, and a new, efficient algorithm for projection interpolation. The modified raw projection data are transferred back to the CT scanner device where CT slices are regenerated using the built-in reconstruction operator. The algorithm was tested on a CT calibration phantom in which the density of inserted objects are known and on clinical prostate cases with two hip prostheses. The results are evaluated using the CT number and shape of the objects. RESULTS: The validations on a CT calibration phantom with various inserts of known densities show that the algorithm improved the overall image quality by restoring the shape and the representative CT number of the objects in the image. For the clinical hip replacement cases, a large fraction of the bladder, rectum, and prostate that were not visible on the original CT slices were recovered using the algorithm. Precise contouring of the target volume was thus feasible. Without this enhancement, physicians would have drawn bigger margins to be sure to include the target and, at the same time, could have prescribed a lower dose to keep the same level of normal tissue toxicity. CONCLUSIONS: In both phantom experiment and patient studies, the algorithm resulted in significant artifact reduction with increases in the reliability of planning procedure for the case of metallic hip prostheses. This algorithm is now clinically used as a preprocessing before treatment planning for metal artifact reduction.

Algorithms↗

PubMed1996

X-ray microscopy: preparations for studies of frozen hydrated specimens.

X-ray microscopes provide higher resolution than visible light microscopes. Wet, biological materials with a water thickness of up to about 10 microns can be imaged with good contrast using soft X-rays with wavelengths between the oxygen and carbon absorption edges (at 24 and 43 A). The Stony Brook group has developed and operates a scanning transmission X-ray microscope (STXM) at the National Synchrotron Light Source (NSLS) at Brookhaven National Laboratory. The microscope is used for imaging with a current resolution of 50 nm, and for elemental and chemical state mapping. Radiation damage imposes a significant limitation upon high resolution X-ray microscopy of room temperature wet specimens. Experience from electron microscopy suggests that cryo techniques allow vitrified specimens to be imaged repeatedly. This is due to the increased radiation stability of biological specimens in the frozen hydrated state. Better radiation stability has been shown recently with a cryo transmission X-ray microscope developed by the University of Göttingen, operating at the BESSY storage ring in Berlin, Germany. At Stony Brook, we are developing a cryo scanning transmission X-ray microscope (CryoSTXM) to carry out imaging and spectro-microscopy experiments on frozen hydrated specimens. This article will give an outlook onto the research projects that we plan to perform using the CryoSTXM.

Animals↗

PubMed1998

Quantitative detection of glaucomatous damage at the posterior pole by retinal thickness mapping. A pilot study.

OBJECTIVE: The posterior pole ganglion cell bodies form a substantial fraction of the retinal thickness, prompting the authors to study the feasibility of detecting, by scanning retinal thickness analysis, retinal changes at the posterior pole due to glaucomatous damage. STUDY DESIGN: Nonconsecutive case series. PARTICIPANTS: One or both eyes of patients with chronic open-angle glaucoma who presented with either a superoinferior asymmetry in visual fields or a localized field loss or a nerve fiber layer defect visible on photography were recruited. Twenty-nine eyes of 18 patients were studied. INTERVENTIONS: A laser slit was projected on the retina and scanned, in 400 msec, across a 2- x 2-mm area of the fundus, yielding optical cross-sections that were digitally recorded. Nine such scans covered the central 20 degrees of the fundus. The optical cross-sections were analyzed by an operator-free algorithm to yield a three-or two-dimensional color map. The asymmetry (difference) between the visual sensitivity of the upper and lower hemifields was compared with the asymmetry in retinal thickness deviation from normal. RESULTS: Large losses (up to 34%) in retinal thickness were detected at the posterior pole of patients with glaucoma due to the loss of ganglion cells and nerve fibers. A statistically significant correlation was found between the asymmetry in visual sensitivity loss and the asymmetry in deviation from normal thickness (r = 0.72; P < 0.0005). CONCLUSIONS: Mapping of the retinal thickness may provide a sensitive method for the detection and monitoring of early glaucomatous tissue loss in the posterior pole, which is unique due to the combination of (1) the direct measurement of neuroretinal loss in the central field of vision; (2) the mapping capability; and (3) the rapid image acquisition.

Adult↗

PubMed1984

Patient characteristics and age-dependent sub-populations in severe fibrocystic breast disease--the Hjørring project.

This study aimed at providing a detailed anamnestic, clinical, and mammographical characterization of 109 patients with fibrocystic breast disease, who were selected on the basis of pronounced mastodynia, prominent palpable structure and mammographical confirmation of the clinical diagnosis. Since these patients were selected for subsequent therapy, and most of them also underwent various hormonal investigations, accurate differential diagnosis was considered essential. Therefore, X-ray mammography was supplemented as required with adenography, galactography, and aspiration of cysts followed by aerography. Additionally, the results for most study variables were recorded by means of standardized scoring systems. On the basis of this characterization, three diagnostic sub-groups of fibrocystic disease could be distinguished: 20 patients with prominent glandular structure but no visible cysts (group A), 43 patients with prominent glandular structure as well as small (less than 1 cm) cysts (group B), and 46 patients with both small and large (greater than or equal to 1 cm) cysts. The three groups differ significantly in mean age (33.1 +/- 5.5 (SD), 39.2 +/- 4.9, and 43.7 +/- 4.6 years in groups A, B, and C, respectively). There was a significant trend towards increasing duration of breast complaints, and patients with a history of greater than 5 years account for 45, 65, and 74% in groups A, B, and C, respectively. Moreover, most of the study variables, viz. mastodynia, palpable structure, amount of glandular tissue, non-cystic nodularity, small cysts, duct ectasia, nipple discharge, and fibrosis, also tended to increase significantly in intensity and/or frequency from group A to B to C.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed2002

Is diffusion imaging appearance an independent predictor of outcome after ischemic stroke?

BACKGROUND: MR diffusion-weighted imaging (DWI) in ischemic stroke can be quantified by calculating the apparent diffusion coefficient (ADC) or measuring lesion volume. OBJECTIVE: To clarify the association between DWI lesion parameters, clinical stroke severity at baseline, and the relationship with functional outcome. METHODS: Consecutive patients with stroke were categorized for stroke type (Oxford Community Stroke Project Classification [OCSP]) and severity (Canadian Neurologic Scale [CN Scale]) before DWI. The ratio of the trace of the apparent diffusion tensor in the ischemic lesion to the mirror image area in the contralateral hemisphere was calculated ( r). The volume of the visible lesion on DWI was measured. Any visible lesion on T2-weighted imaging (T2WI) was noted. All assessments were blind to all other information. A blinded observer obtained a 6-month Rankin score. Univariate and multivariate analyses were performed to test for independent associations with outcome. RESULTS: In 108 patients, those with lower (i.e., more abnormal) r values had more severe strokes according to the CN Scale (p = 0.01) and the OCSP stroke type (p = 0.002), a large lesion on DWI (p = 0.05), a visible lesion on T2WI (p = 0.001), and poor 6-month functional outcome (p = 0.009). However, on logistic regression, neither r nor DWI lesion volume were independent predictors of 6-month outcome over and above age and stroke severity. CONCLUSION: The r is associated with functional outcome, but that is because it and DWI lesion volume are also associated with stroke severity. Although DWI lesion features are univariate surrogate outcome predictors, the authors were unable to show that they were independent outcome predictors in the current study. Differences between these and other results may be due to differences in study design, sample size, and case mix.

Adult↗

PubMed1993

The non-invasive monitoring of low dose, infusional 5-fluorouracil and its modulation by interferon-alpha using in vivo 19F magnetic resonance spectroscopy in patients with colorectal cancer: a pilot study.

BACKGROUND: 5-Fluorouracil (5-FU) is the most widely used cytotoxic drug in oncology and the only one useful in the management of colorectal cancer - a leading cause of cancer death worldwide. Recent studies of 5-FU have focused on increasing efficacy and reducing toxicity by varying the delivery schedule and combining it with modulators. With the development of whole body magnetic resonance systems it is now possible to examine the metabolism of 5-FU in vivo by exploiting the magnetic properties of the fluorine atom which is an integral component of the drug. PATIENTS AND METHODS: Magnetic Resonance Spectroscopy (MRS) was used to non-invasively monitor the metabolism of 5-FU in the liver metastases of colorectal cancer patients. The patients were treated with a continuous low dose intravenous infusion of 5-FU until the point of refractory disease, at which time interferon-alpha was added with the objective of modulating 5-FU activity. MRS was performed at specific phases of the treatment. RESULTS: Twenty-six patients were treated with 5-FU, 11 (42%) achieving partial response. Of the 15 given interferon when disease became refractory to 5-FU, 4 showed signs of further response. In patients observed by MRS during the first 8 weeks of 5-FU treatment, those with a visible 5-FU signal were likely to respond to treatment (p = 0.017). At the time of interferon-alpha addition, MRS showed that 7 patients developed new or increased 5-FU signals, and 4 patients showed a signal from the active metabolites of 5-FU. The patients who exhibited a new or increased 5-FU signal were more likely to show further response to interferon-alpha (p = 0.007). CONCLUSIONS: MRS is a powerful technique for monitoring intratumoural metabolism and modulation of 5-FU enabling prediction of tumour outcome. Direct metabolic information may facilitate the rapid development of optimal clinical schedules for 5-FU and its modulators, thus maximising antitumour effect and minimising toxicity to the patient. This technique may be applied to other areas of clinical medicine where knowledge of the tissue metabolism of a fluorinated drug is of interest.

Antineoplastic Combined Chemotherapy Protocols↗

PubMedDate not supplied

Fitting in or standing out: nursing workgroup diversity and unit-level outcomes.

BACKGROUND: Despite growing diversity in the nursing workforce, there has been limited investigation of the implications of diversity to the performance of nursing workgroups. OBJECTIVES: The aim of this study was to examine relationships among two categories of nursing workgroup diversity (highly visible and job related), intervening workgroup processes (workgroup cohesion and initiative), and workgroup performance (affective and cognitive). METHODS: A descriptive design with path analysis was used to test two models derived from Pelled's intervening process theory. Registered nurse (RN) and patient data from 222 nursing units at 126 hospitals, collected as part of the Outcomes Research in Nursing Administration Project (ORNA-II), were used. Registered nurses provided demographic data used to estimate workgroup diversity (age, race, unit tenure, educational background, and RN experience) and completed questionnaires measuring workgroup cohesion and initiative. Patients completed a satisfaction survey, and these data, along with unit-level patient falls and medication errors, were used to measure workgroup performance. RESULTS: Our findings failed to support the intervening process theory. No direct effects between diversity and intervening process variables were found. Cohesion and initiative did not mediate the relationships between diversity and workgroup performance. However, workgroup cohesion predicted greater patient satisfaction (p < .01) and higher levels of met expectations for symptom management (p < .01), whereas workgroup initiative predicted fewer patient falls (p < .01). DISCUSSION: Diversity may have little, if any, effect on nursing workgroup performance. Cohesion and initiative warrant further research as possible mediators of the relationship between patient outcomes and variables like nurse staffing, experience, and expertise.

Accidental Falls↗