Training the assessors for the General Medical Council's Performance Procedures.

From July 1997, the General Medical Council (GMC) has had the power to investigate doctors whose performance is considered to be seriously deficient. Assessment procedures have been developed for all medical specialties to include peer review of performance in practice and tests of competence. Peer review is conducted by teams of at least two medical assessors and one lay assessor. A comprehensive training programme for assessors has been developed that simulates the context of a typical practice-based assessment and has been tailored for 12 medical specialties. The training includes the principles of assessment, familiarization with the assessment instruments and supervised practice in assessment methods used during the peer review visit. High fidelity is achieved through the use of actors who simulate third party interviewees and trained doctors who role play the assessee. A subgroup of assessors, selected to lead the assessment teams, undergo training in handling group dynamics, report writing and in defending the assessment report against legal challenge. Debriefing of assessors following real assessments has been strongly positive with regard to their preparedness and confidence in undertaking the assessment.

Phospholipase D1 is required for efficient mating projection formation in Saccharomyces cerevisiae.

Phospholipase D1 (PLD1) is an important enzyme involved in lipid signal transduction in eukaryotes. A role for PLD1 in signaling in Saccharomyces cerevisiae was examined. Pheromone response in yeast is controlled by a well-characterized protein kinase cascade. Loss of PLD1 activity was found to impair pheromone-induced changes in cellular morphology that result in formation of mating projections. The rate at which projections appeared following pheromone treatment was delayed, suggesting that PLD1 facilitates the execution of a rate-limiting step in morphogenesis. Mutants were found to be less sensitive to pheromone, again arguing that PLD1 is acting at a rate-limiting step. The fact that morphogenesis is most dramatically affected indicates that PLD1 functions primarily in the morphogenic branch of the pheromone response pathway.

Evaluation of head examinations produced with a mobile CT unit.

Recent years have seen the development of mobile CT units, designed for use in operating theatres, intensive care units and accident and emergency departments. One such unit is the Tomoscan M (Philips, Utrecht, The Netherlands). It operates with a maximum tube voltage of 130 kV, and a maximum tube current of only 50 mA. This study tested whether acceptable quality CT images of the brain could be produced on the mobile unit with these parameters. 44 consecutive normal head examinations performed on the mobile scanner were compared with 35 examinations from two conventional CT units. Two independent readers scored the examinations for noise and artefact. CT dose index (CTDI) values for the three CT units were obtained in free air as an estimate of patient dose. Differences in artefact score between CT units were generally small, but noise scores were worse when using the Tomoscan M with a 2 s slice time. The lowest CTDI values were obtained with the Somatom DRH (Siemens, Erlangen, Germany) unit and the highest with the SR 7000 (Philips, Utrecht, The Netherlands), with values from Tomoscan M, in all except one case, falling between these values for the protocols used in the study. The measured scattered radiation doses from the Tomoscan M are presented.

Imaging the thoracic manifestations of AIDS.

Pulmonary complications occur in over half of patients with AIDS at some point in their illness. A chest X-ray is a valuable first-line investigation. The plain film and computed tomographic features of these complications are described and several examples illustrated. The role of computed tomography, including high resolution scanning techniques in further investigation and management, is discussed.

Magnetic resonance renography: optimisation of pulse sequence parameters and Gd-DTPA dose, and comparison with radionuclide renography.

The aim of this study was to assess the feasibility of magnetic resonance renography (MRR) using gadolinium diethylenetriaminepentaacetic acid (Gd-DTPA) in comparison with conventional radionuclide renography (RR) using technetium-99m-DTPA (99mTc-DTPA). MRR has many advantages over RR, including lack of ionising radiation, increased spatial resolution, and visible background anatomy. By optimising the pulse sequence, we developed an MRR protocol in which signal intensity is linear with Gd-DTPA concentration over a clinically relevant range. Twenty-nine patients and a volunteer were studied using this protocol. Magnetic resonance renography was performed using three different doses of Gd-DTPA: 0.1 mmol kg-1 (n = 13), 0.05 mmol kg-1 (n = 7), and 0.025 mmol kg-1 (n = 9). Each patient was also assessed using radionuclide renography. The resulting renograms were assessed in terms of time to peak signal intensity, signal decrease after peak, and kidney function ratios calculated from both the areas underneath and the slopes of the uptake curves. We have shown that the MR renograms obtained using low dose Gd-DTPA correlate best with the radionuclide renograms. Remaining discrepancies may be explained by variations in the injection procedures (hence in arterial input functions) and the limited coverage of the three MRR slices compared to the whole body projection of RR. Furthermore, at high local concentrations, signal becomes independent of T1 and is dominated by T2.

The use of antibiotic prophylaxis in radiology departments for patients at high-risk of infective endocarditis.

Patients with a prosthetic heart valve, or a history of endocarditis are at particular risk of developing infective endocarditis during a bacteraemia which may follow many gastrointestinal and genito-urinary radiological procedures. The current British Society for Antimicrobial Chemotherapy guidelines (1992) do recommend antibiotic prophylaxis for these high-risk patients prior to instrumentation of the gastrointestinal or genito-urinary tracts. Routine antibiotic prophylaxis for patients with damaged native valves or heart murmurs is recommended prior to dental procedures only. A questionnaire enquiring about prescribing practice prior to several radiological investigations known to be associated with bacteraemia was sent to 192 radiology departments and 126 replied. Only 38 of the 126 respondents have a prescribing policy for antibiotic prophylaxis in high-risk groups. Fifty-eight departments employ antibiotic prophylaxis prior to one or more of the procedures named in the questionnaire, but only 30 of these have mechanisms for identifying at-risk patients. Forty-eight departments keep recommended antibiotics in the department.

Posterior pituitary ectopia and hypopituitarism--magnetic resonance appearances of four cases and a review of the literature.

In four patients presenting in childhood with varying degrees of hypopituitarism, magnetic resonance imaging (MRI) showed a reduction in size of the normal pituitary fossa contents and an absent or very narrow stalk. A high signal intensity, enhancing area at the base of the stalk, having the appearances and signal characteristics of the posterior pituitary, was seen in each case. We discuss the case histories and MR findings in our patients and review the relevant literature.

Computed tomography in the evaluation of cutaneous T-cell lymphoma.

The computed tomography (CT) scans performed in 28 patients with cutaneous T-cell lymphoma (CTCL) were reviewed. Fifteen patients had clinically advanced cutaneous mycosis fungoides, six patients Sézary syndrome and seven variant CTCL. Of the 40 scans available 12 were normal, 15 indeterminate and 13 abnormal. Indeterminate and abnormal nodes showed a predilection for inguinal and axillary sites with a relative sparing of deep nodal regions. Visceral involvement was infrequent. In six patients CT detected abnormalities not obvious clinically and upstaged the disease. CT should be performed as part of the initial staging and as a baseline for follow-up in patients with advanced mycosis fungoides, Sézary syndrome and variant CTCL.

Lymphocytic adenohypophysitis: magnetic resonance imaging features of two new cases and a review of the literature.

Lymphocytic adenohypophysitis can cause pituitary expansion and hypopituitarism closely mimicking the features of a pituitary adenoma. Discrimination between these two conditions is of importance since, despite the similarity of their presentation, there are significant differences in pathophysiology. In contrast to pituitary adenoma, lymphocytic adenohypophysitis occurs almost exclusively in young women in relation to pregnancy, there is a preference for destruction of ACTH and TSH secreting cells and computed tomographic scanning shows uniform contrast enhancement in a proportion of cases. There is, as yet, no proven specific non-surgical treatment. There are anecdotal reports of a beneficial effect of steroids but there is also evidence that spontaneous resolution may occur. We have reviewed the literature and report two new cases of lymphocytic adenohypophysitis both of whom exhibited early striking diffuse homogeneous contrast enhancement on magnetic resonance imaging scanning which we suggest may be a diagnostic feature of this condition.

Symptomatic intracranial involvement by mycosis fungoides.

Involvement of the central and peripheral nervous system by mycosis fungoides is rare and usually occurs in the presence of widespread cutaneous and visceral disease. We describe a patient with mycosis fungoides, previously confined to the skin, who developed intracranial parenchymal disease with no evidence of systemic involvement.

Pictorial review: the imaging features of lower limb Klippel-Trenaunay syndrome.

The Klippel-Trenaunay syndrome is a rare mesodermal abnormality causing venous anomalies, cutaneous capillary naevi with bone and soft tissue hypertrophy of one or more limbs. In this pictorial review we illustrate the plain film, venographic, ultrasound and magnetic resonance imaging features of Klippel-Trenaunay syndrome affecting the lower limb.

A comparison of CT and MRI in the assessment of the pituitary and parasellar region.

We have carried out a prospective study to compare high resolution thin slice, contrast-enhanced, axial computed tomography (CT) with unenhanced magnetic resonance imaging (MRI) at 1.5T in the assessment of the pituitary and parasellar region. Forty patients with suspected pituitary disease presenting to an endocrine unit were studied. MRI was superior to CT for the identification of the posterior pituitary and pituitary stalk and was better at showing the cystic nature of tumours. Visualization of the optic chiasm and assessment of displacement of the optic chiasm and the carotid arteries were also better with MRI. CT was equally good at showing cavernous sinus displacement or invasion, sphenoid sinus invasion and erosion of the floor of the sella turcica and was the only technique able to show calcification of the gland. More focal abnormalities were seen in the pituitary gland with CT than with unenhanced MRI, but there was a higher false positive rate for microadenoma detection with CT. All the scans were interpreted separately by three observers, two radiologists and one clinician. The percentage agreement between the observers for the identification of pituitary and parasellar structures was better for MRI than for CT and the clinician in particular found interpretation of the MR images easier. MRI thus not only gives more information overall than CT but it is a more reliable technique between different observers for the assessment of the pituitary and parasellar region.

A double-blind clinical study comparing the safety, tolerance and efficacy of ioversol and iohexol in intravenous urography.

A double-blind trial in 80 patients showed no significant difference in the efficacy, tolerance and safety for intravenous urography between the new contrast medium Ioversol (Optiray Mallinckrodt Inc.) and the well established medium Iohexol (Omnipaque, Nycomed [UK] Ltd). Minor transient rises in AST/ALT were noted in approximately 10% of each group which were regarded as clinically insignificant. Both media were well tolerated with no significant side-effects.

The role of transvaginal ultrasound in the assessment of the female pelvis.

Transabdominal ultrasound of the female pelvis has been compared with transvaginal ultrasound, using a 7.5 MHz transducer, in 80 women. Transvaginal ultrasound required less patient time and was preferred in 56% of patients. Image quality was superior in 72% of cases, and visualisation of the pelvic organs was equivalent with each technique. Transabdominal ultrasound gives a more global view of the pelvis, and is of more value in assessing large pelvic masses. Transvaginal ultrasound is of more value in assessing early pregnancy, ectopic pregnancy, ovarian abnormalities, and for visualising the ovaries following hysterectomy.

Fracture of the sella turcica: a report of three cases.

Fractures of the sella turcica are rare. Recognition of fractures in this area is very important as serious immediate and delayed neurological, endocrine and vascular complications may occur. Most of these patients will develop at least one cranial nerve palsy; a significant number will develop hypopituitarism and a few will develop local vascular abnormalities.