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Biomedical subjects

G Needham

Publications and source records attributed to G Needham.

At least 19 recordsLinked to original sources
PubMed2002

Effects of mailed dissemination of the Royal College of Radiologists' guidelines on general practitioner referrals for radiography: a time series analysis.

AIM: To evaluate the effect of postal dissemination of the third edition of the Royal College of Radiologists' (RCR) guidelines on general practitioner referrals for radiography. MATERIALS AND METHODS: An interrupted time series using monthly data for 34 months before and 14 months after dissemination of the guidelines was employed. Data were abstracted for the period April 1994 to March 1998 from the computerized administrative systems of open access radiological services provided by two teaching hospitals in one region of Scotland. The time series results are contrasted with those obtained by using a simple before and after design. RESULTS: A total of 117 747 imaging requests from general practice were received in the two departments. There were no significant effects of disseminating the guidelines on the total number of requests, or on requests for individual examinations. If a simple before and after study had been used, then we would have erroneously concluded that significant changes had occurred in referral practice for 11 of the 18 procedures concerned. CONCLUSION: Mailing of copies of the RCR guidelines had a small effect on general practitioners' use of X-ray investigations of uncertain clinical significance. Additional dissemination and implementation strategies appear necessary to promote the use of guidelines.

Family Practice↗
PubMed2001

Effect of audit and feedback, and reminder messages on primary-care radiology referrals: a randomised trial.

BACKGROUND: Radiological tests are often used by general practitioners (GPs). These tests can be overused and contribute little to clinical management. We aimed to assess two methods of reducing GP requests for radiological tests in accordance with the UK Royal College of Radiologists' guidelines on lumbar spine and knee radiographs. METHODS: We assessed audit and feedback, and educational reminder messages in six radiology departments and 244 general practices that they served. The study was a before-and-after, pragmatic, cluster randomised controlled trial with a 232 factorial design. A random subset of GP patients' records were examined for concordance with the guidelines. The main outcome measure was number of radiograph requests per 1000 patients per year. Analysis was by intention to treat. FINDINGS: The effect of educational reminder messages (ie, the change in request rate after intervention) was an absolute change of -1.53 (95% CI -2.5 to -0.57) for lumbar spine and of -1.61 (-2.6 to -0.62) for knee radiographs, both relative reductions of about 20%. The effect of audit and feedback was an absolute change of -0.07 (-1.3 to 0.9) for lumbar spine of 0.04 (-0.95 to 1.03) for knee radiograph requests, both relative reductions of about 1%. Concordance between groups did not differ significantly. INTERPRETATION: 6-monthly feedback of audit data is ineffective but the routine attachment of educational reminder messages to radiographs is effective and does not affect quality of referrals. Any department of radiology that handles referrals from primary care could deliver this intervention to good effect.

Adult↗
PubMed2001

What is achieved by mammographic surveillance after breast conservation treatment for breast cancer?

BACKGROUND: After breast conservation surgery for breast cancer, patients are followed up by regular clinical examination and mammography, at intervals which vary according to local practice. However, the optimum interval remains unclear with current guidelines suggesting mammography should be carried out every 1 to 2 years. This study has investigated this aspect and, in particular, whether mammography or clinical examination or both allowed an early detection of recurrence of the disease in the conserved breast. METHODS: A total of 695 patients who had undergone breast conservation surgery were identified from a database of prospectively recorded data during the period 1990 to 1995. Clinical examination and annual mammography were performed in accordance with local protocol. The results of clinical examination, mammography, and local recurrence rates were evaluated. RESULTS: A total of 2,181 mammograms were undertaken in the 695 patients studied. Local recurrence of disease in the conserved breast occurred in 21 patients (3%), at a mean follow-up of 3.5 years. The first identification of tumor recurrence was by clinical examination in 11 patients with local recurrence, and by the surveillance mammography in the other 10 patients with local recurrence. Overall, mammography detected the local recurrence in 13 of 20 (65%) patients who underwent this examination. In the other patients, the recurrence was detected on clinical examination only. In addition, in 52 patients, mammography was falsely positive, giving a false positive rate of 2.3%. Contralateral cancers in the opposite breast were detected in 2 patients. CONCLUSIONS: The detection of local disease after breast conservation surgery requires both clinical examination and mammography. In the context of our follow-up policy, in 52% of patients with local recurrence, this was first identified by clinical examination. Disease recurrence was identified in the other 48% of patients by mammographic surveillance. Overall, mammography will identify or confirm local recurrence in two thirds of women. However, in a small number of cases (2.3% in our series) mammography will give false positive results. New imaging modalities to assist in the diagnosis of local recurrence of disease after breast conservation surgery are required.

Adult↗
PubMed2000

Assessment of maxillary sinus volume for the sinus lift operation by three-dimensional magnetic resonance imaging.

OBJECTIVES: To calculate sinus and bone graft volumes and vertical bone heights from sequential magnetic resonance imaging (MRI) examinations in patients undergoing a sinus lift operation. METHODS: MRI scans were obtained pre-operatively and at 10 days and 10 weeks post-operatively, using a 0.95 tesla MRI scanner and a three-dimensional (3D) magnetisation prepared, rapid acquisition gradient-echo (MP-RAGE) sequence. RESULTS: Estimates of the bone graft volumes required for a desired vertical bone height were made from the pre-operative MRI scan. Measurements of the graft volumes and bone heights actually achieved were made from the post-operative scans. The MRI appearance of the graft changed between the 10 day and 10 week scans. CONCLUSIONS: We have proposed a technique which has the potential to give the surgeon an estimate of the optimum volume of graft for the sinus lift operation from the pre-operative MRI scan alone and demonstrated its application in a single patient. Changes in the sequential MRI appearance of the graft are consistent with replacement of fluid by a matrix of trabecular bone.

Adolescent↗
PubMed2000

Parasitic mites of honey bees: life history, implications, and impact.

The hive of the honey bee is a suitable habitat for diverse mites (Acari), including nonparasitic, omnivorous, and pollen-feeding species, and parasites. The biology and damage of the three main pest species Acarapis woodi, Varroa jacobsoni, and Tropilaelaps clareae is reviewed, along with detection and control methods. The hypothesis that Acarapis woodi is a recently evolved species is rejected. Mite-associated bee pathologies (mostly viral) also cause increasing losses to apiaries. Future studies on bee mites are beset by three main problems: (a) The recent discovery of several new honey bee species and new bee-parasitizing mite species (along with the probability that several species are masquerading under the name Varroa jacobsoni) may bring about new bee-mite associations and increase damage to beekeeping; (b) methods for studying bee pathologies caused by viruses are still largely lacking; (c) few bee- and consumer-friendly methods for controlling bee mites in large apiaries are available.

Animals↗
PubMed1999

DISCERN: an instrument for judging the quality of written consumer health information on treatment choices.

OBJECTIVE: To develop a short instrument, called DISCERN, which will enable patients and information providers to judge the quality of written information about treatment choices. DISCERN will also facilitate the production of new, high quality, evidence-based consumer health information. DESIGN: An expert panel, representing a range of expertise in consumer health information, generated criteria from a random sample of information for three medical conditions with varying degrees of evidence: myocardial infarction, endometriosis, and chronic fatigue syndrome. A graft instrument, based on this analysis, was tested by the panel on a random sample of new material for the same three conditions. The panel re-drafted the instrument to take account of the results of the test. The DISCERN instrument was finally tested by a national sample of 15 information providers and 13 self help group members on a random sample of leaflets from 19 major national self help organisations. Participants also completed an 8 item questionnaire concerning the face and content validity of the instrument. RESULTS: Chance corrected agreement (weighted kappa) for the overall quality rating was kappa = 0.53 (95% CI kappa = 0.48 to kappa = 0.59) among the expert panel, kappa = 0.40 (95% CI kappa = 0.36 to kappa = 0.43) among information providers, and kappa = 0.23 (95% CI kappa = 0.19 to kappa = 0.27) among self help group members. Higher agreement levels were associated with experience of using the instrument and with professional knowledge of consumer health information. Levels of agreement varied across individual items on the instrument, reflecting the need for subjectivity in rating certain criteria. The trends in levels of agreement were similar among all groups. The final instrument consisted of 15 questions plus an overall quality rating. Responses to the questionnaire after the final testing revealed the instrument to have good face and content validity and to be generally applicable. CONCLUSIONS: DISCERN is a reliable and valid instrument for judging the quality of written consumer health information. While some subjectivity is required for rating certain criteria, the findings demonstrate that the instrument can be applied by experienced users and providers of health information to discriminate between publications of high and low quality. The instrument will also be of benefit to patients, though its use will be improved by training.

Endometritis↗
PubMed1999

The accuracy of "one-stop" diagnosis for 1,110 patients presenting to a symptomatic breast clinic.

UNLABELLED: To minimise delay in diagnosis and reduce patient anxiety, triple assessment with immediate reporting has been used in our symptomatic breast clinic since 1991. This article examines the accuracy of the diagnostic modalities used and the efficacy of the "one-stop" diagnostic policy. The data on 1,110 new patients presenting to the symptomatic breast clinic between January and July 1993, were analysed and subsequent three year follow-up and outcome established. Fine needle aspiration cytology (FNAC) gave the highest predictive value (97.3%) with a sensitivity of 93.5% and a specificity of 98.1%. Ultrasonography provided a 97.0% prediction with a sensitivity of 88.9% and a specificity of 97.4%, whereas mammography had a prediction of 96.4% with sensitivity of 93.2% and a specificity of 96.7%. When the mammogram or ultrasound scan were reported as unequivocally benign (M1), there were no missed cancers. The false positive and false negative rates for FNAC were 0% and 1.4%, respectively. Following assessment, a diagnosis was made in 96% of patients. Sixty-two percent of the patients were discharged at the first clinic visit. Four breast malignancies were subsequently diagnosed in the discharged group; two with new microcalcifications due to ductal carcinoma in situ, one with invasive disease in a different quadrant of the breast from that originally investigated, and in one patient the cancer was missed. CONCLUSION: A "one-stop" symptomatic breast clinic provides an accurate and effective means of establishing a correct diagnosis.

Adolescent↗
PubMed1998

Incident round cancers: what lessons can we learn?

At the time of implementation of the National Health Service Breast Screening Programme a range of targets were set, and have since been updated. This study looks at a subset of cancers detected by screening - the incident round cancers - which are not currently identified and addressed by the targets. In our first incident round we screened 24838 women and detected 112 breast cancers in 111 women. On the basis of a two-stage retrospective evaluation of the prevalent round mammograms in these 111 women, we classified the prevalent mammograms as false negative 21 (19%), minimal signs 32 (28%) and new tumours 59 (53%). Analysis of the radiographic features revealed a disproportionate number with parenchymal deformity (21%) and asymmetry (17%) among the missed tumours when compared to all tumours detected by our screening programme (12% and < 1%, respectively). Identification and quantification of these incidence detected missed cancers could be incorporated into the Quality Assurance Data Set, and used as another performance indicator. Reviewing the mammograms proved a valuable teaching exercise and has allowed us to develop a test set of challenging mammograms.

Breast Neoplasms↗
PubMed1998

Routine receiver operating characteristic analysis in mammography as a measure of radiologists' performance.

A system for calculating receiver operating characteristic (ROC) curves from routine audit data is described. Both diagnostic opinion and pathology outcome data from the symptomatic mammography department were recorded in an audit database, from which ROC curves were calculated. A comparison of overall radiologists' performance was made and the appropriate performance indices discussed. Similar data were collected from the breast screening centre where the same radiologists read mammograms. The radiologists' performance in the symptomatic department was compared with that in the breast screening centre and was found to be better in the screening centre. The difference could not be wholly attributed to the different age distribution of women and highlighted the different nature of the diagnostic task and the differing sampled populations. ROC curves were drawn for different clinical signs to determine any particular area of difficulty the radiologist may experience. ROC analysis as part of routine audit can be used for maintaining and improving the quality of an individual's performance, and targeting learning on areas of particular weakness.

Adult↗
PubMed1997

Temporomandibular joint MRI: a 2-D gradient-echo technique.

Magnetic resonance imaging (MRI) of the temporomandibular joint (TMJ) has been most commonly performed using spin-echo sequences. Gradient-echo sequences have previously been investigated in the context of 3-D and 'dynamic' (pseudo-kinematic) imaging. We have used gradient-echo to improve image quality in static studies with rapid acquisition, high spatial resolution (512 x 512 matrix) and excellent contrast resolution. Using pragmatic methods and a non-randomized study group we have demonstrated a definite advantage to image quality, and thus diagnostic confidence, from the use of a gradient-echo high spatial resolution sequence incorporating split acquisition open mouth views.

Adolescent↗
PubMed1996

Choice of contrast enhancement index for dynamic magnetic resonance mammography.

Indices are often used in dynamic MRI of the breast to quantitate signal enhancement within suspicious lesions. Two indices are commonly used: one calculates the difference in pre- and postcontrast signal intensity, normalised to a base-line signal intensity such as that of fat (which does not enhance) whilst the other calculates the ratio of pre- to postcontrast signal intensity. The results of a computational simulation are presented which demonstrate the superiority of the normalised signal difference index, based on the criterion that the best index is that which is least influenced by initial tissue T1. This hypothesis was tested by comparing the two indices in a group of patients with clinical or mammographic suspicion of recurrent breast carcinoma. Of 37 patient examinations using Gadolinium enhanced MRI of the breast, 11 patients showed 13 lesions with some degree of enhancement, which were subsequently diagnosed histologically as either benign or malignant. The normalised signal difference index showed no overlap between the benign and malignant groups, whereas some overlap was observed with the signal ratio index. The clinical findings are therefore consistent with the results of the computational simulation.

Adult↗
PubMed1996

Measurement of spin-lattice relaxation times with FLASH for dynamic MRI of the breast.

Using a variable flip angle gradient refocused imaging technique, dynamic quantitative T1 relaxation maps acquired before and after the administration of a gadolinium contrast bolus enable the concentration-time curve of the paramagnetic agent in breast tissue to be calculated. This imaging technique has the aim of improving the diagnostic accuracy of MR mammography. Measurements with phantoms of calibrated T1 values have been carried out to investigate the accuracy of the method, with particular reference to errors caused by incomplete spoiling of residual transverse magnetization and inaccurate radio frequency (RF) flip-angle settings. A clinical example is presented. The method has potential use for any patient study which necessitates rapid quantitation of changing in vivo T1 values as a result of contrast agent injection.

Breast Neoplasms↗
PubMed1996

Dynamic magnetic resonance mammography of both breasts following local excision and radiotherapy for breast carcinoma.

The purpose of this study was to evaluate a dynamic gadolinium-diethylene-triaminepentacetate (Gd-DTPA) enhanced magnetic resonance mammography (MRM) protocol, incorporating image subtraction and using a dedicated double breast coil, in patients with treated breast cancer. 36 patients who had undergone breast conserving surgery and radiotherapy, with clinical or mammographic suspicion of locally recurrent breast carcinoma, were examined. 3D rapid volume imaging of both breasts was performed before and repeated three times, at 1, 2 and 3 min, following Gd-DTPA enhancement. Image subtraction allowed identification of enhancing lesions and quantitative analysis of these was performed. Five patients had six lesions demonstrating rapid enhancement in the first minute, all of which were histologically confirmed recurrent or second primary tumours. Slower enhancement was seen in six benign lesions and diffuse enhancement was seen in one patient within 6 months of treatment. The dynamic protocol used allowed sufficient temporal resolution for distinguishing malignant from benign lesions at the site of previous surgery and ensured that both breasts were imaged in their entirety, thus enabling the diagnosis of multifocal and second primary tumours.

Adult↗
PubMed1996

MRI as an aid to the fitting of tracheo-oesophageal Blom-Singer valves post-laryngectomy.

The Blom-Singer valve is a device for facilitating speech in patients who have undergone total laryngectomy. The valve is inserted into a surgically created tracheo-oesophageal fistula. Fitting the valve and determining the correct length and direction of the fistula, although usually straightforward, can be difficult. We describe two patients in whom MR imaging of the fistula tract has aided valve fitting.

Adult↗