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Biomedical subjects

M J Gleeson

Publications and source records attributed to M J Gleeson.

At least 37 records · Page 2Linked to original sources
PubMed1994

Accurate frameless registration of MR and CT images of the head: applications in planning surgery and radiation therapy.

PURPOSE: To evaluate the feasibility and efficacy of a three-dimensional image registration technique for planning skull base surgery, performing frameless image registration for stereotaxic neurosurgery, and staging nasopharyngeal carcinoma. MATERIALS AND METHODS: Computed tomographic (CT) and magnetic resonance (MR) images from 35 patients were registered by identifying 12-16 homologous landmarks with each modality. Images were displayed as overlaid sections or rendered three-dimensional scenes. The clarity of the combined images from 15 patients undergoing skull base surgery was compared with that of the conventional displays. RESULTS: Images were combined for three applications, with an accuracy of 1-2 mm. For the 15 patients undergoing skull base surgery, the combined images were significantly better at depicting the relationship between bone and lesion than conventional display (P < .01). CONCLUSION: MR and CT images of the head can be accurately registered without using external markers or substantially altering image acquisition protocols. The resulting images can show the radiologic information more clearly than conventional viewing.

Adult↗
PubMed1994

Combined and three-dimensional rendered multimodal data for planning cranial base surgery: a prospective evaluation.

Magnetic resonance (MR), X-ray computed tomography (CT), and angiographic images best depict soft tissue, bone, and blood vessels respectively. No one on its own is sufficient in the preoperative assessment of cranial base lesions. We have developed and evaluated a computational technique for the three-dimensional (3D) combination and display of multimodality images for planning cranial base surgery. This evaluation was prospective and performed in such a way that the results could be quantified. Eight patients (three acoustic neuromas, four subfrontal and suprasellar meningiomas, and one petrous apex meningioma) underwent MR, CT, and MR angiographic investigations. These images were registered with anatomical landmarks rather than an external frame. Two techniques were used to display the resulting combined images: multiple slices in which bone from CT was overlaid on soft tissue from registered MR and pseudo-3D-rendered movie sequences showing bone from CT, lesions and optic nerves from MR, and blood vessels from MR angiography. The advantages of the combined displays compared with those of conventional methods of viewing were assessed prospectively by the operating surgeon and by an independent surgeon, and the results were compared with operative findings. The preoperative assessment showed a significant improvement (P < 0.05, sign test) in the depiction of both individual structures (lesion and bone from overlaid slices and lesion and vasculature from 3D-rendered displays) and structural relationships (tumor-bone relationships from overlaid slices and of tumor-vasculature relationships from 3D-rendered displays). The operative findings indicated that a more accurate interpretation of this information was possible from the combined images.

Adult↗
PubMed1993

Tissue-bonded iontophoretic cystostomy: conceptual and experimental considerations.

We describe a conceptual model for drainage of the dysfunctional bladder. Experimental data from investigations involving several species of animals are presented to support the hypothesis that mature tissue-bonded alloplastic tubes drain urine effectively and are tolerant and resistant to endogenous and exogenous bacteria. We conclude that preliminary clinical trials of a tissue-bonded cystostomy are warranted. We postulate that success in these trials may offer a new alternative for the management of severe vesical dysfunction.

Animals↗
PubMed1993

Is retrograde ureterography indicated in pelviureteric junction obstruction?

The role of retrograde ureterography in the management of pelviureteric junction (PUJ) obstruction remains controversial and it has recently been reiterated that visualisation of the entire ureter on the affected side is mandatory owing to the high incidence of other ureteric abnormalities. In a review of 119 consecutive adult pyeloplasties carried out over a 9-year period, only 2 ureteric abnormalities were found in association with PUJ obstruction (duplex ureter/3-cm proximal stricture). Other anatomical abnormalities included aberrant vessels, fascial bands and renal anomalies. Most secondary abnormalities were undiagnosed prior to surgery and all were easily dealt with per-operatively.

Adolescent↗
PubMed1993

Comparison of reagent strip (dipstick) and microscopic haematuria in urological out-patients.

Dipstick (reagent strip) and microscopic urine analysis for haematuria was performed prospectively on 1000 consecutive urine samples taken from urological out-patients. Haematuria was present in 185 samples (18.5%) and absent in 687 (68.7%) using both tests; 98 samples (9.8%) had dipstick haematuria that was not confirmed by microscopy and 30 samples (3%) had microscopic haematuria that was missed on dipstick urine analysis. Dipstick urine analysis had a sensitivity of 86.1% and a specificity of 85%. This study confirms that reagent strip testing for haematuria has both false positive and false negative results and indicates that cytoscopy should be considered in all patients with suspected haematuria.

Adolescent↗
PubMed1993

Morphological features of human Reissner's membrane.

Light and electromicroscopic investigations of Reissner's membrane were undertaken on 10 cochleae from 6 patients with normal hearing for their age. The membrane consisted of two layers, an epithelium and a mesothelium separated by a basement membrane. The mesothelium was formed by a single thin layer which was intermittently discontinuous. The melanocytes were localized on the mesothelial side of the basement membrane. Their numbers was 2-4 times greater in the upper half of the basal turn and in the middle turn than elsewhere. The epithelium was much thicker and had more irregular features than the mesothelium. It was composed of two types of epithelial cells, flat and rounded. The flat cells were more regular in shape than the rounded cells and they were mainly distributed in the middle and apical turns. Judging from their structure they were in a resting state. The rounded cells covered a smaller area than the flat ones and had numerous microvilli. They assumed three different shapes, cuboidal, spindle-form and spherical and were arranged in four different patterns, namely bands, strands, whorls and clusters. The rounded cells were the most active according to the composition of the cytoplasm and dominated the cell population in the hook and the lower half of the basal turn where the age-related sensorineural degeneration is most apparent.

Aged↗
PubMed1993

Acoustic tumour volume and the prediction of facial nerve functional outcome from intraoperative monitoring.

The long-term facial function in 26 patients undergoing surgery to remove an acoustic neuroma has been related to the tumour volume (ml) estimated by computerized tomogram (CT) reconstruction techniques. Analysis of data allowed accurate categorization into 'small' (= < 5 ml) and 'large' (> 5 ml) tumours, which gave the maximum prognostic distinction between two groups for facial recovery. Thus, of the 14 patients with small volume tumours, 11 achieved a good (House grade I or II) facial outcome compared with 1 out of 12 patients with large tumours. Combined with the information derived from the assessment of intraoperative facial nerve electrical integrity using a combined nerve stimulator and EMG monitor, long-term facial function was predictable for all small tumours defined by volume. This represented a 15% improvement in prediction of facial recovery when defining tumour size by maximum linear dimension (small = < 2.5 cm, large > 2.5 cm). The calculations of volume obtained using a simplified ellipsoidal model compared well with CT reconstructed values (r2 = 0.85), and gave identical prediction and outcome comparisons.

Adolescent↗
PubMed1992

A comparative study of calcium sodium alginate (Kaltostat) and bismuth tribromophenate (Xeroform) packing in the management of epistaxis.

A prospective study was undertaken to compare the efficacy of calcium sodium alginate fibre (Kaltostat) to petrolatum gauze impregnated with bismuth tribromophenate (Xeroform) for the control of epistaxes that require hospital admission. Forty patients presenting with severe epistaxis requring hospital admission were treated with either Kaltostat or Xeroform nasal packs. Allocation to either treatment group was made randomly. The composition of each group in terms of age, sex distribution, aetiology of epistaxis and severity of bleed was not significantly different. There was no significant difference in the efficacy or patient acceptability of either therapeutic agent. It is concluded that calcium sodium alginate fibre should be considered as an acceptable alternative to traditional gauze packing.

Adolescent↗
PubMed1992

Morphometric analysis of the cochlear nerve in man.

Fiber diameters were analyzed in the meatal segment of the cochlear nerve from 7 temporal bones obtained from 7 patients. Two patients had normal hearing for their age. Two had sustained noise exposure and one had presbyacusis of predominantly neural type. The cochleae displayed characteristic degeneration patterns. The other two manifested hearing loss of unspecified type. The fiber diameters ranged from 0.5 to 11 microns. The diameter distribution was unimodal in all seven nerves. The means of the diameters ranged from 4.2 to 5.5 microns. They were significantly different between patients with age-related normal hearing on the one hand and patients with noise induced hearing loss and neural presbyacusis on the other. The findings are discussed in relation to changes in nerve conduction speed and hearing loss; a possible correlation between the fiber diameter distribution and the tonotopical arrangement of the cochlea is suggested.

Cochlear Nerve↗
PubMed1992

Magnetic resonance imaging of the parotid gland using the STIR sequence.

The object of this study was to determine the efficiency of the short tau inversion recovery (STIR) sequence in the assessment of salivary disease. Sixteen patients with tumours either in or adjacent to the parotid gland were imaged using a 1.5T Philips Gyroscan, with a standard head coil. T1-weighted spin-echo and STIR sequences were obtained in multiple planes and assessed independently by each of the authors. Positive fine needle aspiration cytology or histological proof of the nature of the imaged lesions was obtained for every patient. T1-weighted spin-echo images were most useful for visualizing anatomical structures and for identification of the facial nerve. All lesions were visible with T1-weighted images but were very much more conspicuous in the STIR sequences, for which a minimal lesion resolution of 6 mm was achieved. No contrast enhancement was required. It was not possible to determine the pathological nature of the lesion by scan appearance only. Our conclusion is that a combination of T1-weighted spin-echo and STIR sequences in the axial and coronal planes is the preferred protocol for salivary gland imaging.

Adolescent↗
PubMed1992

Antroconchopexy for surgical treatment of perennial rhinitis.

We report on a rhinomanometric assessment of eleven patients undergoing antroconchopexy for relief of a "stuffy" nose. This little-known procedure involves the lateralization of the inferior turbinate through a large intranasal antrostomy. Our results demonstrate a significant improvement in postoperative inspiratory and expiratory nasal resistance. There was also a significant improvement in patient's scoring for nasal obstruction. Finer points of the surgical technique, and indications for the procedure are discussed.

Adult↗