Biomedical subjects
Publications and source records attributed to G F Maskell.
Two patients with pelvic abscesses underwent fluoroscopic guided transrectal catheter drainage using a simple modification in standard technique. A 9F vascular sheath allows contrast to be instilled through the side port and the seal avoids any leakage back through the sheath. It also provides a safe, quick and precise needle puncture at the selected site.
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Intravascular lipomata are rare tumours occurring in the major central veins. We report a case in which an asymptomatic lipoma of the superior vena cava presented as mediastinal widening on a chest radiograph. The CT and MR features are presented.
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The appearance of the ascending aorta was studied in 53 patients undergoing computed tomography on a modern system capable of routine 1 second data acquisition times. Motion artifact caused a blurred aortic outline in 48 patients; the extent was objectively and subjectively assessed. The maximum and minimum cross-sectional aortic areas were measured at the margins of the blur. The area of the blur, expressed as a fraction of the minimum aortic cross-sectional area, decreased with age (P < 0.001) and was significantly smaller in the 13 patients with known cardiovascular problems (P < 0.05). These findings were substantiated by the subjective gradings which showed less marked artifacts amongst elderly patients (although this observation did not reach statistical significance). Artifacts were less prominent in 16 patients with evidence of aortic wall calcification, both on subjective grading (P < 0.05) and formal area measurements (P < 0.05). These observations lead us to believe our postulation that this artifact is an indicator of aortic distensibility and thus, indirectly, of cardiovascular status.
Computed tomography of the thorax was performed in 30 patients with Wegener's granulomatosis to define the anatomical basis of pulmonary involvement. A wide variety of parenchymal and bronchial abnormalities was demonstrated in addition to the cavitary nodules commonly described. The high incidence (40%) of bronchial abnormalities in these patients may suggest that bronchocentric injury is more important in the pathogenesis of lung involvement in this disease than has previously been considered. Serial scans in individual patients showed broad correlation between the extent of the pulmonary abnormalities and the clinical and immunological markers of disease activity.
One fifth of patients selected for cochlear implants have such bony irregularities in the cochlear duct that full insertion of a multichannel electrode array is impossible. Three cases of cochlear deafness are presented where pre- and post-operative radiology played an important part in the management. Standard CT at 2 mm cuts is compared with ultra high resolution CT at 1 mm cuts. The pitfall of poor definition is that the inexperienced surgeon may find himself unexpectedly drilling out an obliterated cochlear duct. Sections 30 degrees caudal to Reid's infra orbito-meatal base line at 1 mm intervals give maximum information for minimum radiation. Plain films show the placement of individual platinum electrode contacts in relation to the spiral 'frequency map' of the cochlea. This is vital information for the audiologist who has to route specific frequencies to specific sites within the ear for a good hearing result.