PubMed Health⌕ Search

Biomedical subjects

A J Wilson

Publications and source records attributed to A J Wilson.

At least 91 records · Page 5Linked to original sources
PubMed1996

Prevalence of red marrow around the knee joint in adults as demonstrated on magnetic resonance imaging.

RATIONALE AND OBJECTIVES: We determined the prevalence of red marrow around the knee joint in adults and evaluated variations with age, gender, and other variables. METHODS: One hundred ninety-nine adult patients presenting for routine knee magnetic resonance (MR) imaging completed a questionnaire that covered age, gender, menstrual history, past pregnancies, smoking history, and medications. The presence or absence of visible red marrow in the distal femur and proximal tibia on both coronal and sagittal MR images was recorded for each patient. Associations between the presence of red marrow and the other recorded variables then were evaluated. RESULTS: Red marrow was present in more than half of the women and less than one sixth of the men, a statistically significant difference. The age distribution of red marrow in men and women also was different. Red marrow was the most common in women aged 30-60 years. In men, there was no clear-cut age trend. Red marrow also was more likely to be present in obese individuals and smokers. No association was found between the presence of red marrow and any of the other recorded variables. CONCLUSION: There are clear gender, age, obesity, and smoking-related differences in the prevalence of red marrow around the knee joint in adults. Red marrow is relatively common in this site in all age groups, and its presence should not be a cause for clinical concern.

Adolescent↗
PubMed1996

Single-dose i.v. granisetron in the prevention of postoperative nausea and vomiting.

In this randomized, double-blind, parallel group, placebo-controlled, dose-ranging study, we have compared three doses (0.1 mg, 1.0 mg and 3.0 mg) of the 5-HT3 receptor antagonist, granisetron (Kytril), as prophylactic therapy for the prevention of postoperative nausea and vomiting. The aims were to determine the optimal dose of granisetron and to evaluate its safety profile. We studied 527 adult patients, undergoing elective open abdominal surgery or vaginal hysterectomy during general anaesthesia. Antiemetic prophylaxis with a single dose of granisetron 1.0 mg or 3.0 mg resulted in a significant reduction (P < 0.001 compared with placebo) in the numbers of patients experiencing postoperative vomiting, or nausea, or who achieved total control during the postoperative periods 0-6 h and 0-24 h. The two higher doses of granisetron (1.0 mg and 3.0 mg) provided effective prophylaxis against vomiting, with 78% and 77% of patients, respectively, being free from vomiting in the first 6 h after surgery, and 63% and 62% in the first 24 h. This compares with 50% and 34% at 0-6 h and 0-24 h, respectively, in the placebo group. Granisetron was well tolerated and the optimum dose was 1.0 mg.

Adult↗
PubMed1996

Eosinophil apoptosis and the resolution of airway inflammation in asthma.

Asthma is accompanied by the accumulation of potentially damaging eosinophils within inflamed airways. How eosinophils may be removed from the airways is not clear. The phagocytic removal of eosinophils in vitro requires that they undergo apoptosis, a form of cell death. We postulated that eosinophil apoptosis may occur in vivo, promoting the removal of airway eosinophils and the resolution of inflammation in asthma. We examined eosinophil apoptosis in sputum samples obtained from 11 subjects during an asthma exacerbation and 2 wk after corticosteroid treatment of the exacerbation. Airway function improved following corticosteroid treatment, and eosinophilic inflammation subsided, with significant decreases occurring in the number of airway eosinophils and the percentage of activated eosinophils. The proportion of apoptotic airway eosinophils increased significantly following corticosteroid treatment, and eosinophil products were apparent within macrophages. Our findings indicate that eosinophil apoptosis is clinically relevant in asthma. Apoptosis may represent a mechanism that promotes the resolution of eosinophilic inflammation in asthma.

Adrenal Cortex Hormones↗
PubMed1996

Dynamics of respiratory patterning in normal infants and infants who subsequently died of the sudden infant death syndrome.

Despite evidence that respiratory control mechanisms may be altered in infants who succumb to the sudden infant death syndrome (SIDS), overall respiratory variability in SIDS victims is comparable to that of control infants. We assessed dynamic characteristics of breathing in 16 recordings of apparently healthy infants who subsequently died of SIDS, and 35 recordings of age-matched control infants. Each breath-to-breath interval in 10-min epochs of quiet sleep and rapid eye movement sleep was plotted against the previous interval. Dispersion of next-intervals was determined after short, intermediate, and long interbreath intervals. In SIDS victims, dispersion after long intervals (slow respiratory rates) was significantly restricted relative to control infants. Moreover, after long breath-to-breath intervals, SIDS victims showed smaller mean breath-to-breath changes in respiratory rate than did controls. The findings indicate that breath-to-breath respiratory patterns differ in infants who succumb to SIDS, and the differences occur preferentially at low respiratory rates.

Analysis of Variance↗
PubMed1996

Usefulness of turbo spin-echo MR imaging in the evaluation of meniscal tears: comparison with a conventional spin-echo sequence.

OBJECTIVE: Fast (turbo) spin-echo imaging techniques have replaced conventional spin-echo protocols in a large proportion of MR applications, with the principle advantage of decreased imaging time. The choice of echo train length is a key determinant of time savings realized, but the echo train length can also adversely affect image quality if too many echoes are incorporated into an image. Several recent studies have shown conflicting results regarding the usefulness of turbo spin-echo imaging in the evaluation of meniscal tears. We compare a turbo spin-echo sequence that has an echo train length of five with a conventional spin-echo sequence for evaluating meniscal tears. SUBJECTS AND METHODS: Forty knees in 39 consecutive patients referred for MR study of the knee were imaged using both conventional spin-echo and turbo spin-echo sequences. The turbo spin-echo sequence provided both proton density-weighted and T2-weighted images (dual echo technique) with an effective echo-train length of five. Nineteen knees (38 menisci) were studied arthroscopically. The arthroscopic findings were considered the reference standard. Spin-echo and turbo spin-echo images were reviewed retrospectively, and results were compared statistically. RESULTS: Of the 80 menisci evaluated with MR imaging, spin-echo and turbo spin-echo images provided concordant results in 95% of cases, with no statistically significant difference found between the two techniques (p < .05). Seventeen tears were found at arthroscopy in 38 menisci studied. Spin-echo and turbo spin-echo imaging had identical specificities (90%) and similar sensitivities (88% and 82%, respectively). CONCLUSION: This study shows that proton density-weighted sequences with an echo train length of five preserve sufficient high-spatial-frequency information to provide performance similar to that of conventional spin-echo sequences. Our data support the conclusion that fast spin-echo imaging with short echo train length is a reasonable substitute for conventional spin-echo imaging in the evaluation of the knee.

Adult↗
PubMed1996

The use of continuous quality improvement methods to implement practice guidelines in asthma.

National asthma management guidelines have improved awareness of the rising morbidity and mortality from asthma but have not been widely implemented at a local level. This paper describes the use of continuous quality improvement techniques to facilitate the implementation of asthma management guidelines within a tertiary hospital setting. A baseline audit demonstrated satisfactory emergency assessment and treatment, but identified poor compliance with the patient education aspects of the asthma management plan. An evaluation of the literature demonstrated that programs combining asthma education and management were effective when directed towards adults with a recent severe asthma exacerbation. An asthma education and management service was developed to address these deficits. A repeat audit was conducted which identified improvements in asthma control and management skills for patients attending the education program, together with reductions in asthma re-admission rates for patients referred to the service. Ongoing quality assessments will target non-attenders to the service and the maintenance of asthma skills. An area Asthma Health Outcomes Council was formed to address the issues of asthma management throughout the area health service.

Adult↗
PubMed1995

Quantitative analysis of solitary lesions of bone.

RATIONALE AND OBJECTIVES: To quantitate the radiographic features of common solitary lesions of bone using vector analysis to optimize their radiographic description. METHODS: Plain radiographs of 709 solitary bone lesions were reviewed. Relevant demographic, anatomic, and structural data were cataloged. These data were used to approximate the vector space defined by all possible solitary lesions of bone. Vector space analysis on the entire set of lesions was performed to determine similarities among and between lesion types. RESULTS: The 709 lesions generated 614 separate vectors within the appearance vector space. Only 10 vectors were represented more than 3 times, indicating great variability among and between most lesion types. Osteochondromas (with two vectors repeated 10 and 15 times, respectively) and peripheral chondrosarcomas (with one vector repeated 5 times) were relatively uniform in appearance. Gender bias was present for multiple types of lesions. Larger lesions that involved more than one anatomic center were more likely to be malignant. Lesions occurring in the femoral diaphysis and pelvic flat bones were statistically more likely to be malignant. CONCLUSIONS: Analysis shows that most lesions have highly varied vectors in the appearances within the vector space. More in-depth analysis of each lesion type using this quantitative technique is required to better define individual lesion subspaces and hence their radiographic appearances with respect to other bone lesions.

Bias↗
PubMed1995

Quantitative analysis of the plain radiographic appearance of aneurysmal bone cysts.

RATIONAL AND OBJECTIVES: To quantitate radiographic features that distinguish the plain radiographic appearance of aneurysmal bone cyst (ABC) from other solitary lesions of bone. MATERIALS AND METHODS: Seven hundred nine cases of focal bone lesions, including 32 ABCs were analyzed according to demographic, anatomic, and plain radiographic features. Vector analysis of groups of features was performed to determine those that are most sensitive and specific for the appearance of ABC in contrast with other lesions in the data base. RESULTS: Aneurysmal bone cysts most consistently are medullary-based, either eccentric or centric (94%), show lysis (100%), cortical thinning (97%), enlargement of the host bone (100%), and geographic bone destruction (94%). They have well-defined edges (84%), no fallen fragment (100%), no evidence of periosteal reaction (75%), and no visible matrix (91%). Although they typically occur in the metadiaphysis of long bones, the anatomic location and demographic data did not significantly affect the sensitivity or specificity for detection of ABCs. The vector analysis-generated differential diagnoses include giant cell tumor, unicameral bone cyst, nonossifying fibroma, enchondroma, and fibrous dysplasia as the major lesions.

Adolescent↗
PubMed1995

Quantitative analysis of the plain radiographic appearance of central chondrosarcoma of bone.

RATIONALE AND OBJECTIVE: To quantitate radiographic features that distinguish the plain radiographic appearance of central chondrosarcoma from other solitary bone lesions. MATERIALS AND METHODS: Seven hundred nine cases of focal bone lesions, including 37 central chondrosarcomas, were analyzed according to demographic, anatomic, and plain radiographic features. Vector analysis of groups of features was performed to determine those that are most sensitive and specific for the appearance of central chondrosarcoma in contrast with other lesions in the data base. RESULTS: The most specific appearance of long bone central chondrosarcomas was a lesion within the medullary cavity with geographic destruction, containing calcified matrix and a diameter greater than 5.9 cm, or arising within the proximal metaphysis or diaphysis. These features all are present in 9 (39%) of the 23 long bone central chondrosarcomas and in less than 1% of other lesions. In flat bone lesions, calcified matrix and either geographic bone destruction, medullary location, or enlargement of the host bone were 100% specific but of low sensitivity, identifying 7 (50%), 7 (50%), and 6 (41%) of the 14 flat bone chondrosarcomas, respectively. Inclusion of calcified matrix in the description is essential to make the criteria specific but excludes several of the most aggressive long bone chondrosarcomas. The vector analysis-generated differential diagnosis include osteosarcoma, fibrous dysplasia, unicameral bone cysts, aneurysmal bone cysts, malignant fibrous histiocytoma, and Ewing sarcoma. CONCLUSIONS: A relatively specific set of radiographic features can be defined to assist in plain film diagnosis of central chondrosarcoma, but there are many chondrosarcomas that fall outside these parameters. Thus, while not sufficiently sensitive to allow accurate plain film diagnosis in all cases, these criteria serve as an improved foundation for differential diagnosis.

Adolescent↗
PubMed1995

Quantitative analysis of the plain radiographic appearance of eosinophilic granuloma.

RATIONALE AND OBJECTIVES: To quantitate features that distinguish the plain radiographic appearance of eosinophilic granuloma (EG) from other solitary lesions of bone. MATERIALS AND METHODS: Seven hundred nine focal bone lesions, including 26 EGs, were analyzed according to demographic, anatomic, and plain radiographic features. Vector analysis of groups of features was performed to determine those that are most sensitive and specific for the appearance of EG in contrast to other lesions in the data base. RESULTS: The radiographic appearance of EGs was most consistently that of a medullary based lytic lesion (100%) with geographic destruction (76.9%), lobular contour (73.1%), and well-defined edges (73.1%). Long bone lesions showed these features more frequently than EGs in other locations. Periosteal reaction was visible in all long bone lesions but in only one nonlong bone lesion (5.9%). Characterization of EG in long bones as a lytic, medullary-based metaphyseal or diaphyseal lesion with geographic destruction, lobular contours, periosteal reaction, no matrix, and no subarticular extension showed a sensitivity of 55.6% of EG and prevalence of 22.7%. The vector analysis-generated differential diagnoses include unicameral bone cyst, aneurysmal bone cyst, giant cell tumor, Brodie's abscess, enchondroma, chondrosarcoma, and malignant fibrous histiocytoma. CONCLUSIONS: The radiographic appearance of EG is relatively nonspecific but, using vector analysis, can be better elucidated than in current textbook descriptions.

Adolescent↗
PubMed1995

Quantitative analysis of the plain radiographic appearance of nonossifying fibroma.

RATIONAL AND OBJECTIVES: To quantitate radiographic features that distinguish the plain radiographic appearance of nonossifying fibroma (NOF) from other solitary lesions of bone. MATERIALS AND METHODS: Seven hundred nine cases of focal bone lesions, including 34 NOFs, were analyzed according to demographic, anatomic, and plain radiographic features. Vector analysis of groups of features was performed to determine those that are most sensitive and specific for the appearance of NOF in contrast to other lesions in the data base. RESULTS: The radiographic appearance of NOFs was most consistently a medullary based (97%), lytic lesion (100%) with geographic bone destruction (100%), marginal sclerosis (97%), and well-defined edges (94%). A statistically significant number of lesions were located in the distal aspect of long bones. Unicameral bone cyst shared the most radiographic features with the NOF. Vector analysis showed a large degree of overlap between NOF and other lesions such as aneurysmal bone cyst, chondromyxoid fibroma, and eosinophilic granuloma. The description that optimized sensitivity and prevalence for detection of NOF is a medullary based, ovoid lesion in the distal or proximal portions of a long bone with well-defined edges, a partial or complete rind of sclerosis, and absence of fallen fragment, periosteal reaction, and cortical disruption. CONCLUSION: The radiographic appearance of NOF is relatively nonspecific but, using vector analysis, can be better elucidated over current textbook descriptions.

Adolescent↗
PubMed1995

Digitized radiographs in skeletal trauma: a performance comparison between a digital workstation and the original film images.

PURPOSE: To evaluate the diagnostic performance of a teleradiology system in skeletal trauma. MATERIALS AND METHODS: Radiographs from 180 skeletal trauma patients were digitized (matrix, 2,000 x 2,500) and transmitted to a remote digital viewing console (1,200-line monitor). Four radiologists interpreted both the original film images and digital images. Each reader was asked to identify, locate, and characterize fractures and dislocations. Receiver operating characteristic curves were generated, and the results of the original and digitized film readings were compared. RESULTS: All readers performed better with the original film when interpreting fractures. Although the patterns varied between readers, all had statistically significant differences (P < .01) for the two image types. There was no statistically significant difference in performance with the two images when dislocations were diagnosed. CONCLUSION: The system tested is not a satisfactory alternative to the original radiograph for routine reading of fracture films.

Computer Communication Networks↗
PubMed1995

Three-compartment wrist arthrography: direct comparison of digital subtraction with nonsubtraction images.

PURPOSE: To determine the diagnostic value of digital subtraction and fluoroscopic spot images in wrist arthrography, alone and in combination. MATERIALS AND METHODS: Randomized selective bilateral three-compartment wrist arthrography was performed in 64 patients. The fluoroscopic spot and digital subtraction images were read separately by two radiologists without knowledge of the clinical data. RESULTS: One hundred twenty communicating defects were found in 69 wrists in 42 patients. Fluoroscopic spot radiographs alone depicted defects in all 69 wrists, but precise localization was not possible in 10 defects. Subtraction images alone demonstrated 59 defects. The defects not seen with digital subtraction imaging were identified after wrist motion. Digital subtraction images demonstrated defects earlier during the joint injection and demonstrated the exact site of the 10 defects not localized on the nonsubtracted images. CONCLUSION: Digital subtraction and fluoroscopic spot images are complementary in wrist arthrography and, when used in combination, increase the ability to localize the sites of defects, although the value added by the subtraction technique is small.

Adolescent↗
PubMed1995

Filmless musculoskeletal radiology: why is it taking so long?

Digital images as an alternative to plain radiographs in musculoskeletal radiology have not been readily accepted to date. This article looks at the different aspects of filmless imaging and offers an opinion concerning this lack of acceptance. Although spatial resolution, image storage, and image transmission present potential problems, the greatest problem is image display. Commercially available workstations do not compete well with the speed and simplicity of the conventional film and view box.

Data Display↗