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Biomedical subjects

M O'Sullivan

Publications and source records attributed to M O'Sullivan.

136 records · Page 8Linked to original sources
PubMedDate not supplied

Enhancement of thoracic masses using nonionic MR contrast agents.

OBJECTIVE: This study evaluated the effect of a new nonionic MR contrast medium, gadodiamide injection (Omniscan; Sanofi-Winthrop), on enhancement of thoracic masses on T1-weighted SE images. MATERIALS AND METHODS: Gadodiamide injection was administered intravenously at a dose of 0.2 mmol/kg to 26 patients with thoracic masses. The T1-weighted images with and without fat suppression and T2-weighted images obtained before contrast medium injection were compared with T1-weighted images obtained at 5, 30, and 45 min and a T1-weighted fat-suppressed image at 10 min after administration of the contrast medium. Enhancement of the thoracic masses and image quality were quantified by measuring signal intensity, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) using muscle and fat as reference tissues. RESULTS: The SNR of the masses increased significantly (p < 0.001) following contrast material injection both on standard T1-weighted sequences and on T1-weighted fat-suppressed images when compared with the precontrast T1-weighted images with and without fat suppression. The CNR (reference tissue muscle) improved significantly (p < 0.001) after contrast medium injection and persisted for 45 min on T1-weighted images compared with those prior to contrast medium. However, there was no significant difference in CNR between the T2-weighted images obtained before and the T1-weighted images obtained after contrast agent administration. On the other hand, the SNR of contrast-enhanced images was significantly better than that of the T2-weighted images. When fat was used as a reference tissue, CNR of the thoracic masses decreased significantly. CONCLUSION: This study shows that gadodiamide injection caused significant enhancement of thoracic masses on T1-weighted images, which rendered high signal intensity to the masses similar to the appearance on T2-weighted images. In comparison with the T2-weighted images, SNR was significantly improved.

Adolescent↗
PubMedDate not supplied

Evaluation of thoracic aortic dissection using breath-holding cine MRI.

OBJECTIVE: Our goal was to determine if breath-hold cine MRI in transaxial planes can be used for the evaluation of thoracic aortic dissection instead of conventional cine MRI since rapid imaging is required in this clinical setting. MATERIALS AND METHODS: Twelve patients with thoracic aortic dissection were imaged using a 1.5 T imager. Breath-hold images were acquired with fast cine MR sequence (TR/TE = 9/2.8, 20 degrees flip angle) using segmented k-space data acquisition. Conventional non-breath-hold cine MR images (TR/TE = 22/7.5, 35 degrees flip angle, 2 averages) were taken with flow and respiratory compensation. RESULTS: Sharpness of edges of the vessels on fast cine MR images was better than that on conventional cine MR images in 34 (57%) of 60 images. Inhomogeneous blood signal in aortic lumen due to motion artifacts was found in 2 (3%) of fast cine MR images and in 15 (25%) of conventional cine MR images. The contrast-to-noise ratios of fast cine MR images were significantly better than those of conventional cine MR images (26.4 +/- 9.1 vs. 18.5 +/- 10.1; p < 0.05) when the region of interest for noise was placed to include ghosting artifacts. CONCLUSION: Breath-hold cine MRI is a rapid technique that gives high quality images of thoracic aortic dissection and can provide a diagnosis in < 10 min of imaging time.

Aged↗
PubMedDate not supplied

Analysis of asbestos fiber burden in lung tissue from mesothelioma patients.

Mesothelioma is a rare neoplasm that occurs most frequently in individuals with previous asbestos exposure. Differences for risk of development of asbestos-related mesothelioma and lung cancer have been attributed to the various types of asbestos, as well as to the dimension of the inhaled fibers. In the present study, 55 individuals with the pathological diagnosis of mesothelioma were evaluated as to ferruginous body and fiber content in lung tissue. The procedures used in the analysis included tissue digestion and analysis of the collected material for ferruginous bodies by light microscopy and for uncoated fibers by analytical transmission electron microscopy. Forty-six of the samples had ferruginous body concentrations of over 1000/per gram dry weight of lung tissue. The majority of the cores of these ferruginous bodies were amosite. Likewise, the most common uncoated asbestos fiber in the tissue was amosite. Only a small percentage of each type of asbestos would have been visible by light microscopy or even potentially by electron microscopy if the magnification was not sufficient to detect those with thin (< 0.2 micron) diameters. The consistent finding in most of the cases was a considerable presence of asbestos, often of mixed types.

Adult↗
PubMedDate not supplied

Which implant for proximal femoral osteotomy in children? A comparison of the AO (ASIF) 90 degree fixed-angle blade plate and the Richards intermediate hip screw.

We reviewed the clinical and radiologic results of 164 proximal femoral osteotomies in 132 children using the AO (ASIF) 90 degree fixed-angle blade plate and the Richards intermediate hip screw to establish the clinical and radiologic outcomes, establish the incidence of complications, and determine the relative indications and contraindications for the two implants. The incidence of complication in this series was 9% (15 complications in 14 osteotomies in 13 patients) including one bursitis, one wound breakdown with exposure of the underlying plate, five infections, two peroneal nerve palsies, one fractured shaft of femur, one fractured neck of femur, two technical errors, one painful nonunion, and one loss of fixation. There were five (3%) revisions in total. Fifty-six osteotomies in 44 patients were performed using the Richards intermediate hip screw, and 108 osteotomies were performed in 88 patients using the AO 90 degree fixed-angle blade plate. We found that both implants were effective with an acceptable rate of complications and revision surgery.

Adolescent↗
PubMedDate not supplied

What do Dublin GPs expect from a psychiatric referral?

The advent of community psychiatry has tended to blur the interface between primary and secondary psychiatric care. We used a postal questionnaire to investigate each new referral from general practice to the public outpatient clinics of three West Dublin Psychiatric Sectors. 70 referrals, from 35 general practitioners, over a four month period in 1991 were analysed, regarding reason for referral and prior management in general practice. On average patients had seen their GP six times over a period of ten months. Mixed anxiety/depression was the most common diagnosis (23%). Medication had been prescribed for 61% of patients and 67% had counselling before referral. Common reasons for referral were: Access to therapies not available directly to the GP (30%); Failure of treatment (20%); To share the burden of chronic care (14%). In only 13% of referrals did the GP wish the psychiatrist to take over care. We conclude that the GPs surveyed undertake extensive pre-referral management of patients with psychological illness. They have well defined expectations of referral and are keen to follow up patients themselves. Future plans for community psychiatric services should take account of this pattern of care.

Affective Symptoms↗
PubMedDate not supplied

Meningococcus: a menace in Cork?

A review of laboratory isolates and notifications of meningococcal disease in the Cork area was conducted for the period 1989-93. The study aimed to describe the epidemiology of meningococcal disease in the area. The incidence of meningococcal disease is high in the Cork area and has been increasing since 1991 with a peak incidence of laboratory confirmed cases of 6.5 per 100,000 in 1993. In the five year review period 113 notifications of meningococcal disease were identified of which 61 (54%) were laboratory confirmed and 52 (46%) were clinically diagnosed only. All laboratory confirmed cases had been notified to the local Director of Community Care/Medical Officer of Health. Group C organisms comprised two-thirds of isolates in 1992 and 1993. Comparison of regional and national incidence rates must be based on laboratory confirmed cases as the criteria for diagnosis and completeness of notifications may vary. A National Infectious Disease Surveillance Centre is vital for monitoring trends and for the coordinated development of a national policy on control and prevention of meningococcal disease.

Age Distribution↗
PubMedDate not supplied

Plantar fibromatosis of the heel in children: a report of 14 cases.

Based on a study of 14 patients younger than 16 years, we found that lumps on the plantar aspect of the anteromedial portion of the heel pad can safely be observed. Many remained small and asymptomatic, some disappeared, and two that required repeated excision biopsy did not subsequently recur. The six patients who were subjected to excision biopsy were found to have plantar fibromatosis. This very precise heel site is a characteristic situation for plantar fibromatosis in childhood.

Adolescent↗