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Biomedical subjects

M E Hansen

Publications and source records attributed to M E Hansen.

32 records · Page 2Linked to original sources
PubMed1990

Assessing the patency of mediastinal and thoracic inlet veins: value of MR imaging.

To assess the accuracy of MR imaging in the evaluation of patients with suspected thoracic venous obstruction, hospital records and MR studies of 31 such patients were reviewed. Gradient-recalled echo, spin-echo, or cine MR techniques were used. In 26 of the 31 patients, venous obstruction was confirmed by CT, venography, sonography, surgery, or autopsy. Causes included tumor invasion, compression of veins, coagulopathy, or indwelling catheters. MR detected an abnormality of the superior vena cava in all 16 cases in which it was seen on other tests. Abnormality of the internal or external jugular veins was detected in all six cases in which other studies were abnormal. Abnormality of veins in the shoulder region was detected by MR in 10 of 12 patients in whom such disease was seen on other tests. The two interpretive errors were caused by nonocclusive clot, short (less than 2-cm) occlusions, and metallic artifact. Overall, MR correctly identified abnormality in 32 of 34 vessels (sensitivity, 94%). In all cases, a negative MR study was found to be a true negative (no false positives in 42 normal vessels; specificity, 100%). We conclude that MR is an accurate means of assessing patency of the thoracic inlet and mediastinal veins. Its noninvasive nature and multiplanar capability contribute to its usefulness in this clinical setting.

Adolescent↗
PubMed1990

Elective and emergency embolotherapy in children and adolescents. Efficacy and safety.

Twenty-one embolizations were performed in 19 children and adolescents. Ten patients underwent emergency embolotherapy to control bleeding from trauma (5), neoplastic disease (2), mycotic aneurysm (1), post-operative bleeding (1), and hemoptysis (1). Nine patients underwent elective embolotherapy. In 5 patients with hypervascular tumors, it was performed as an adjunct to surgery or chemotherapy. In 3 patients, embolotherapy was the primary mode of treatment for vascular malformations in the lung, pelvis, and kidney. One patient with systemic-pulmonary arterial collaterals was treated for high-output congestive heart failure. Embolotherapy was successful in controlling bleeding in all cases. There were no major complications or procedure-related mortalities. Minor complications occurred in 2 patients. Our results indicate that percutaneous transcatheter embolotherapy in children and adolescents is safe and effective and has wide application in both elective and emergency management of vascular lesions in this age group.

Adolescent↗
PubMed1989

Melanocytic nevi in schoolchildren in Queensland.

In a group of 211 schoolchildren in Queensland less than 12 years of age, the mean total melanocytic nevus (mole) count was 28 (median 19), and the mean count for raised nevi was 11 (median 8). The upper aspect of the back and chest were the most commonly affected sites, with the neck being the third. Boys had significantly (p less than 0.01) more melanocytic nevi than girls, and prevalence was highest in children with pale skin and light-colored hair. Nonwhite heritage had a protective effect independent of pigmentary characteristics. Total numbers of nevi on children also were related to maternal tendency to large numbers of moles and to family history of melanoma. The only significant association observed for the presence of large (greater than 5 mm) nevi on children was a family history of melanoma. The children studied come from a general population that has the highest known risk of melanoma. In Australia they have been shown to have the highest prevalence of nevi ever reported in the prepubertal age group. These descriptive data, together with the specific pigmentary and family associations described, extend the known links between benign nevi and malignant melanoma.

Child↗
PubMed1988

Artificial urinary sphincters: plain radiography of malfunction and complications.

Inflatable artificial urinary sphincters provide excellent voluntary continence. Eighty-four consecutive patients underwent implantation of artificial urinary sphincters for intractable urinary incontinence; 33 patients had 58 episodes of sphincter malfunction, and eight patients had eight complications involving a functional prosthetic sphincter. Retrospective analysis was performed to determine the value of plain radiography of the pelvis in patients with sphincter malfunction or complication. The cause of malfunction in the majority of patients was a system leak and subsequent loss of hydraulic fluid (31 occurrences; 53%). Plain radiography permitted correct identification of all instances of fluid leakage in patients with opacified prostheses. Plain radiographs were of no value in examining patients with nonopacified prostheses or the complications of cuff erosion or wound infection. Due to the low cost and noninvasive nature of plain radiography of the pelvis, we conclude that it should be used as the initial diagnostic modality in patients with previously opacified but currently dysfunctional artificial urinary sphincters.

Female↗
PubMedDate not supplied

In vivo determination of human arterial compliance: preliminary investigation of a new technique.

PURPOSE: To obtain more detailed information about the dynamic mechanical properties of human arteries in vivo, using a new technique based on intravascular ultrasound. (IVUS). METHODS: Arterial compliance was measured in the common and/or external iliac arteries of 6 patients using an IVUS device, concurrently obtained intraarterial pressure measurements, and a video motion analysis system. RESULTS: Compliance decreased with increasing vessel diameter and mean arterial pressure. Pre- and postangioplasty measurements were obtained in 2 patients but did not demonstrate a consistent change in compliance following angioplasty. CONCLUSION: We conclude that IVUS provides an accurate means for in vivo determination of human arterial compliance, the practical value of which needs to be established.

Adult↗
PubMedDate not supplied

STIR imaging of synthetic vascular graft infection.

Nine patients with suspected prosthetic vascular graft infection were studied with axial spin echo (SE) and short TI inversion recovery (STIR) magnetic resonance imaging. Images were assessed for presence and extent of abnormality. All patients had either surgical (8/9) or bacteriologic (6/9) confirmation of infection. STIR images better defined the extent of infection and had greater fat-fluid contrast than SE images in 6/9 studies. In 3 cases with peri-graft fluid alone, T2-weighted images had slightly greater contrast, although the STIR images were still diagnostic. STIR imaging can offer improved accuracy in evaluation of suspected prosthetic graft infection when used in conjunction with SE techniques.

Adipose Tissue↗
PubMedDate not supplied

HIV and interventional radiology: a national survey of physician attitudes and behaviors.

PURPOSE: The frequency of parenteral and cutaneous exposure to blood or body fluid during interventional radiologic procedures, current use of barrier precautions by interventional radiologists, and physician attitudes about testing for the human immunodeficiency virus (HIV) and related issues were assessed. MATERIALS AND METHODS: An anonymous survey of interventional radiologists was conducted by mail in November 1991. RESULTS: Of 1,530 surveys, 819 (54%) were returned and 806 (53%) were completed and evaluable. Ninety-six percent of respondents (763 of 794) perform procedures in patients infected with HIV. Sixty-nine percent oppose mandatory testing of physicians for HIV. Eighty-seven percent (693 of 797) reported at least one procedure-related injury (range, 0-99; mean, four). Fifty-eight percent of injuries occurred with use of a sharp instrument (381 of 662), 20% were due to needle recapping (133 of 662), and 7% (44 of 662), to improper disposal of a sharp instrument. Contact between a physician's blood and a patient was reported in only one case (0.2%). Eighty-five percent of respondents (671 of 789) changed their use of barrier precautions in the last 10 years; concerns about HIV were cited by 96% as a reason for change. Reported use of barrier measures was highly variable. CONCLUSION: Exposure to patients' blood or body fluid is not infrequent during interventional radiologic procedures. Exposure of patients to the blood or body fluid of health care workers is rare. Use of recommended precautions in interventional radiology is variable, and practices that could lead to preventable injury remain common. Strategies should be developed to reduce risks even further and to encourage universal compliance with government guidelines.

AIDS Serodiagnosis↗
PubMedDate not supplied

Assessment of azinphosmethyl exposure in California peach harvest workers.

We compared measurements of urinary alkylphosphate metabolites and oxime-induced reactivation of plasma cholinesterase (P-ChE) and erythrocyte acetylcholinesterase (RBC-AChE) with measurements of foliar residues, skin and clothing contamination, and P-ChE and RBC-AChE activities among 20 Northern California peach orchard workers exposed to the organophosphate agent azinphosmethyl (Guthion). Subjects entered orchards treated 30 d previously with azinphosmethyl and worked 21 d in treated fields during the ensuing 6 wk. Dislodgeable foliar residues ranged from 0.32-0.96 micrograms/cm2. Median reduction in RBC-AChE activity was 7% (p < .001) over the initial 3-d period of exposure and 19% (p < .01) over the 6-wk season. Urinary metabolites were the most sensitive indicator of recent exposure and correlated moderately with dermal and clothing levels (rs = +0.31-(+)0.55); urinary metabolites correlated well with RBC-AChE drawn 3 d after exposure began (rs = -0.77). No significant oxime-induced reactivation was found.

Acetylcholinesterase↗