The osteo-odonto-keratoprosthesis (OOKP), although described over 40 years ago, remains the keratoprosthesis of choice for end-stage corneal blindness not amenable to penetrating keratoplasty. It is particularly resilient to a hostile environment such as the dry keratinized eye resulting from severe Stevens-Johnson syndrome, ocular cicatricial pemphigoid, trachoma, and chemical injury. Its rigid optical cylinder gives excellent image resolution and quality. The desirable properties of the theoretical ideal keratoprosthesis is described. The indications, contraindications, and patient assessment (eye, tooth, buccal mucosa, psychology) for OOKP surgery are described. The surgical and anaesthetic techniques are described. Follow-up is life-long in order to detect and treat complications, which include oral, oculoplastic, glaucoma, vitreo-retinal complications and extrusion of the device. Resorption of the osteo-odonto-lamina is responsible for extrusion, and this is more pronounced in tooth allografts. Regular imaging with spiral-CT or electron beam tomography can help detect bone and dentine loss. The optical cylinder design is discussed. Preliminary work towards the development of a synthetic OOKP analogue is described. Finally, we describe how to set up an OOKP national referral center.

This study demonstrates an intimate proximity between the coronary sinus, at its beginning and end, and the mitral valve annulus. It also highlights the close relationship between the great cardiac vein, the annulus and the left ventricular free wall. Assessing the same relationship using the currently available imaging techniques should aid in the successful cannulation of the coronary sinus for various cardiological interventions.

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In primary hyperaldosteronism, it is important to distinguish between unilateral and bilateral disease, as management strategies differ. In the period 1983-95, we identified 34 patients with primary hyperaldosteronism. Following further investigations, a diagnosis of aldosterone-secreting adenoma was made in 17 patients, and surgery was performed. Computed tomography clearly localized an apparent adenoma (discrete adenoma=1 cm diameter; normal contralateral gland) in only 10 of these patients (59%); two of these 'adenomas' were subsequently shown to be hyperplastic glands without adenomas. Histological examination showed adrenal adenomas in the remaining 15 patients. An 'adenoma' also appeared to be clearly localized in 3/17 patients later classified as having bilateral adrenal hyperplasia by adrenal vein sampling. CT scanning, therefore clearly localizes adenomas in only 50% of histologically proven cases, and can also produce misleading results. Adrenal vein sampling results altered our management approach in one third of cases. On the basis of our detailed results we would recommend surgery if there is clear evidence of unilateral aldosterone secretion along with CT findings which may not be strictly localizing but are in keeping with the dominant side on adrenal vein sampling. The decision to refer for surgery in primary hyperaldosteronism can be difficult, and we would caution against too heavy a reliance on CT results when recommending adrenalectomy, and suggest that adrenal vein sampling should remain a routine part of the investigation of patients with primary hyperaldosteronism.

ABSTRACT. Minimal preparation CT colon (MPCTC) is a useful test for frail elderly patients, who tolerate full bowel preparation poorly, and has the potential advantage of identifying extra-colonic pathology. Double reporting has been shown to reduce perception errors in a variety of radiological investigations, and we sought to determine its usefulness for MPCTC. A prospective consecutive cohort of 186 patients undergoing MPCTC for lower gastrointestinal symptoms was double reported. Radiologists were blinded to each report. Data for each report were divided into colonic and extra-colonic findings, with the latter being graded as clinically relevant or irrelevant. Discrepancies between the two reports were identified. A positive colonic lesion was defined as one where direct endoscopic visualisation was recommended. A clinically relevant extra-colonic lesion was defined as one that could impact on future patient management. 13% (24/186) of patients had a significant colonic lesion; 7 of these were identified only by 1 observer, although only 1 was confirmed endoscopically to be cancer. The positive predictive value for colon cancer was 69% for single reporting and 54.5% for double reporting. There were 67 clinically relevant extracolonic lesions, and 25 of these were reported only by only 1 observer. In conclusion, double reporting found one extra-colonic cancer, but at the expense of five unnecessary endoscopic procedures. This seems a reasonable trade-off and we would therefore recommend double reporting. However, implementation would have a significant impact on manpower and service delivery. Minimal preparation CT colon (MPCTC) is a useful, non-invasive, sensitive method for investigation of the colon for carcinoma in frail elderly patients [1][2][3], and has the advantage of being easy to tolerate [4]. Extracolonic organs are inevitably also imaged, which may provide an advantage over the competing modalities of endoscopy and barium enema [5][6][7].It has been shown that double reporting reduces perception error in a number of radiological investigations, including double contrast barium enemas, neuroradiology and mammography [8][9][10][11]. We perform a large number of MPCTC investigations in our institution and, because the colonic result can be easily dichotomised, we felt that the advantages of double reporting could easily be investigated. Methods and materialsLocal ethics committee approval was obtained. A prospective cohort of consecutive patients was included in this study in a single unit over 5 months. These patients were referred for MPCTC for investigation of suspected large bowel carcinoma. Local referral guidelines are that patients over 75 years of age, or younger patients in whom it is thought that full colonic cleansing would be poorly tolerated owing to comorbidity, should have MPCTC.Four consultant radiologists with experience in this technique (8, 5, 4 and 2 years' experience of reporting at consultant level) reported the images. Before starting the study, potential pathologies were divi...