Signal intensity, clinical activity and cross-sectional areas on MRI scans in thyroid eye disease.

The signal intensity from inflamed extra-ocular muscles on short tau inversion recovery (STIR)-sequence magnetic resonance imaging (MRI) is known to correlate with clinical scores of thyroid eye disease (TED) severity. Twenty-one patients who had undergone repeated MRI scanning for TED were studied retrospectively. Signal intensity of extra-ocular muscles (from STIR-sequence MRI) and cross-sectional area (from STIR and T1 MRI) were correlated with Mourits' clinical activity score (CAS). The area of highest signal intensity within the most inflamed extra-ocular muscle, and the average cross-sectional signal intensity of the most inflamed extra-ocular muscle reliably correlated with CAS, and this was maintained as disease activity changed over time. In contrast, isolated measures of muscle cross-sectional area did not correlate with CAS. The extra-ocular muscle cross-sectional area calculated from STIR-sequence MR images was greater than that measured on T1 images. This suggests that muscle area from STIR-sequence MRI may also detect peri-muscular inflammation. We conclude that the peak signal intensity from the most inflamed extra-ocular muscle remains the most reliable correlate of clinical disease activity obtained from these images. STIR-sequence MRI scans provide a number of useful measures of disease activity in TED.

Spontaneous enophthalmos: silent sinus syndrome.

Spontaneous enophthalmos unrelated to trauma or surgery is rare. The term 'silent sinus syndrome' has been used to describe this process where, in particular, there is an absence of any sino-nasal symptoms. The enophthalmos and hypoglobus that occurs in these subjects is caused by atelectasis of the maxillary antrum, which itself appears to be due to chronic maxillary hypoventilation. We report a case of silent sinus syndrome that arose following insertion of a nasogastric tube. Whilst acute paranasal sinusitis is a well-described sequela of nasal intubation, this association with a rare, and as yet unexplained, phenomenon may go some way to explain its aetiology.

Small margin excision of periocular basal cell carcinoma: 5 year results.

BACKGROUND: The traditional surgical management of nodular adnexal basal cell carcinomas (BCC) involves excision with 3-4 mm margins and primary repair. This may remove a significant area of healthy tissue, often necessitating a complicated reconstruction, without the confirmation that tumour excision is complete. METHODS: Nodular adnexal BCCs were excised with 2 mm margins, and the repair delayed for 2 days, providing time for histological confirmation of complete excision with formal paraffin sections. Any incompletely excised tumours underwent further resection, which was facilitated by the undisturbed wound edges. Repair was again delayed until further histological examination had confirmed complete excision. RESULTS: 5 year follow up data were available for 55 patients who had undergone small margin BCC excision with delayed repair. 10 patients required more than one excision to achieve clear margins. There were no recurrences. CONCLUSION: Small margin excision of nodular adnexal BCCs with delayed repair is a safe and efficient method. Delayed repair allows histological confirmation of complete excision and assists further resection if required. Preservation of healthy tissue is maximised allowing less radical reconstructive surgery without resorting to Mohs' labour intensive technique.

Serial STIR magnetic resonance imaging correlates with clinical score of activity in thyroid disease.

PURPOSE: To assess the correlation between inflammatory activity in extraocular muscles measured with serial short tau inversion recovery (STIR) sequence magnetic resonance imaging (MRI) scans and clinical disease activity in thyroid eye disease. METHODS: In this retrospective study, 22 patients with thyroid eye disease who had undergone serial MRI scans using the STIR sequence were assessed. The signal intensity ratio (SIR) of the most inflamed extraocular muscle was compared with the Mourits score (a clinical measure of thyroid eye disease activity). RESULTS: The SIR value has previously been shown to correlate with clinical activity of thyroid eye disease. In a particular patient the SIR value increases in proportion with the clinical features of the disease as assessed by the Mourits rating system. When the change in STIR sequence MRI is compared with the change in Mourits score rating for a given patient the correlation is highly significant (p < 0.001). CONCLUSIONS: This study confirms that serial STIR sequence MRI scans correlate with clinical disease activity. Inflammatory activity in the most inflamed muscle (as measured by SIR) reflects overall disease activity. SIR values obtained from MRI scans provide a useful measure of disease activity and may help in the monitoring and treatment of this condition.

The massively parallel genetic algorithm for RNA folding: MIMD implementation and population variation.

A massively parallel Genetic Algorithm (GA) has been applied to RNA sequence folding on three different computer architectures. The GA, an evolution-like algorithm that is applied to a large population of RNA structures based on a pool of helical stems derived from an RNA sequence, evolves this population in parallel. The algorithm was originally designed and developed for a 16384 processor SIMD (Single Instruction Multiple Data) MasPar MP-2. More recently it has been adapted to a 64 processor MIMD (Multiple Instruction Multiple Data) SGI ORIGIN 2000, and a 512 processor MIMD CRAY T3E. The MIMD version of the algorithm raises issues concerning RNA structure data-layout and processor communication. In addition, the effects of population variation on the predicted results are discussed. Also presented are the scaling properties of the algorithm from the perspective of the number of physical processors utilized and the number of virtual processors (RNA structures) operated upon.

Mini Monoka silicone monocanalicular lacrimal stents: Subjective and objective outcomes.

BACKGROUND. Canalicular injuries and anomalies are relatively common. Despite this, controversy still exists regarding the indications for surgery and best surgical methods. The most favourable intervention would be one that is simple, associated with a high level of subjective and objective outcome, and does not threaten the uninjured or unaffected part of the lacrimal drainage system. This study assesses outcomes of intervention with the Mini Monoka silicone monocanalicular lacrimal stent. METHOD. A single cohort, hospital-based study with retrospective and prospective components. Participants were all identifiable patients at Bristol Eye Hospital in whom the Mini Monoka silicone monocanalicular stent was used for any indication. Retrospective analysis of patient records for all related pre-operative, operative and postoperative data was performed. Prospective analysis of subjective outcome via confidential patient questionnaire and objective outcome via clinical examination was performed. RESULTS. Complete data were obtainable in 13 patients (14 canaliculi) of the identified 22 patients (23 canaliculi). Follow-up was from 12 to 70 months (mean 39 months). A high level of subjective outcome was noted with no patients experiencing significant or disabling symptoms. In terms of objective outcome, 79% achieved canalicular patency. The main complications with this technique were premature stent loss (29%) and stent migration (14%). CONCLUSIONS. The Mini Monoka monocanalicular stent is a safe, effective and simple surgical technique that, unlike bicanalicular procedures, does not threaten the uninjured / unaffected part of the lacrimal drainage system.

Successful teaching of pediatric fluid management using computer methods.

OBJECTIVES: To identify and measure differences in knowledge of pediatric fluid management procedures between students taught by computer tutorial and others taught by lecture or seminar. DESIGN: Cohort analytic study. SETTING: Two community-based medical school pediatric teaching services. PARTICIPANTS: Eighty-nine third-year medical students with no prior pediatric fluid management experience. INTERVENTIONS: Forty-eight students at one community campus completed a microcomputer-based tutorial program that replaced all teaching sessions in pediatric fluid management. Forty-one students from a similar community campus were taught identical content by a pediatric critical care specialist using a seminar, reading material, and handouts. MAIN OUTCOME MEASURES: Scores on 2 free-answer problems on treatment of a dehydrated child, which were graded by a single evaluator blinded to the teaching method used, and scores on a 20-item multiple-choice examination. RESULTS: The computer instruction group achieved significantly higher test scores than the seminar group for both the multiple-choice examination (81.1% vs 62.2%; P<.001) and the free-answer test (85.4% vs. 61.0%; P<.001). CONCLUSIONS: The computer tutorial in fluid therapy has been an effective means of meeting the defined objectives of the pediatric clerkship. Compared with traditional methods, students taught using the computer achieved significantly higher scores on tests of both factual knowledge and practical problem solving.

Small margin (2 mm) excision of peri-ocular basal cell carcinoma with delayed repair.

Successful surgical treatment of peri-ocular basal cell carcinomas requires complete excision. Mohs' micrographic surgery achieves this, but is not readily available in all hospitals. The standard 3-4 mm margin does not guarantee complete excision and histology is often not available until after a repair has been undertaken. The 3-4 mm margin has evolved to deal with all forms of BCC. In our opinion, this margin is unnecessarily large for nodular/ulcerative BCC. We report our interim results of excision of localised BCCs using a 2 mm margin in conjunction with a delayed repair following confirmation of histological clearance. Thirty-one patients were treated in this manner; there have been no recurrences after an average follow-up period of 36 months (range 24-57 months).

Clinical evaluation of scanning laser polarimetry: I. Intraoperator reproducibility and design of a blood vessel removal algorithm.

AIMS: To evaluate the reproducibility of the retardation values (change in polarisation) obtained with the scanning-laser polarimeter in a series of normal subjects and glaucoma patients. To improve the analysis of the raw data by devising and evaluating a blood vessel removal algorithm. METHODS: Scanning laser polarimetry was performed on 10 normal subjects and 10 glaucoma patients. A series of six images was obtained from each eye. The normal subjects were re-imaged 3 months after their initial assessment. The retardation values obtained from each eye were analysed using the authors' own methods, including the use of an algorithm to remove blood vessels from the polar profiles. The reproducibility of these measurements and the performance of the blood vessel removal algorithm were assessed. RESULTS: The "individual point" coefficient of variation was approximately 12.5% for normal subjects and 17.0% for glaucoma patients. The "integral" coefficient of variation for these groups was approximately 5.5% and 9.5% respectively. The reproducibility of the measurements did not improve with an increased number of measurements. There was no difference in the reproducibility of the measurements in normal subjects over time. The blood vessel removal algorithm improved the reproducibility of the measurements when the shape of the profile was assessed. CONCLUSION: The intraoperator reproducibility of retardation values obtained with the scanning laser polarimeter is satisfactory for its use as a clinical tool. The use of a blood vessel removal algorithm improves the reproducibility of the measurements and also assists the clinician in the interpretation of the polar profiles. Furthermore, it allows the construction of normal database polar profiles, thereby enabling the identification, location and quantification of retinal nerve fibre layer damage in an "at risk" individual's polar profile.

Clinical evaluation of scanning laser polarimetry: II. Polar profile shape analysis.

AIMS: To devise a method to describe and quantify the shape of polar profiles obtained with the scanning laser polarimeter and to compare this measurement with other polar profile measurements in a series of normal subjects and glaucoma patients. METHODS: Scanning laser polarimetry was performed on 54 normal subjects and 74 glaucoma patients. The retardation values obtained from one randomly chosen eye of each subject were analysed using our own methods, including the use of an algorithm to remove blood vessels from the polar profiles, an algorithm to standardise the glaucoma profiles to a normal database, and a further algorithm to evaluate the profile shape. The measurements of profile shape were compared with measurements of the absolute and standardised retinal nerve fibre layer thickness obtained with the scanning laser polarimeter. RESULTS: There was no significant difference between the mean retardation values for the normal and glaucomatous subjects in either hemiretina. However, standardisation of the glaucoma retardation values to a normal database produced significant differences at p < 1 x 10-8 in the mean retardation values for these two groups in both hemiretinas. Profile shape measurement analysis produced similar significant differences between the mean retardation values for the normal and glaucomatous subjects in both hemiretinas, although the degree of separation was greater following standardisation of the retardation values. CONCLUSION: The use of an algorithm to standardise an individual's retardation values in conjunction with a blood vessel removal algorithm enables an improvement in the ability of the scanning laser polarimeter to discriminate between normal and glaucomatous patients. The polar profile shape algorithm is independent of standardisation and significantly improves the discrimination between normal and glaucomatous patients, as well as providing additional information regarding the retinal nerve fibre layer.

A drop in pediatric subject examination scores after curriculum changes that emphasize general pediatric topics.

OBJECTIVE: To determine whether emphasizing a limited number of general pediatric objectives and using a test based on them would improve student knowledge of the topic areas. DESIGN: Before-after trial. SETTING: Community-based medical school. SUBJECTS: Third-year medical students on a required clerkship in pediatrics. INTERVENTION: Six core objectives: recognizing the seriously ill child, stabilizing such a child, fluid and electrolyte requirements and therapy, newborn care, well child care, and variability of normal vital signs in children based on their age were defined and a modified essay examination was constructed. The test was given to pediatric students close to the end of their clerkship. In study year 1, no warning was given about the examination and results did not affect student grades. In study year 2, passing all items was a requirement and failure required remedial oral examination of any missed items. All students completed the National Board of Medical Examiners pediatric subject examination. RESULTS: For 7 of 8 essay items, significant increases in numbers of students passing were seen in study year 2, but students scored 51 points lower on the National Board of Medical Examiners pediatric subject examination (P=.002). The decrease in scores was not seen in any other clerkship or among pediatric students from a different campus of the medical school. CONCLUSIONS: Emphasis on core objectives and an essay examination significantly improved students' knowledge of the defined topics but decreased the scores on the National Board of Medical Examiners subject examination. This may be attributable to a difference in content between the 2 tests. Faculty proposing new curriculum guidelines need to review student assessment methods to avoid such unexpected changes in scores.

Cilioretinal artery occlusion following scleral reinforcement surgery.

A 12-year-old high myope girl presented with a cilioretinal artery occlusion in her left eye. Three years previously, she had undergone posterior scleral support surgery to prevent the progression of her myopia. The general medical workup of the patient did not reveal any causative factor for retinal artery occlusion. A possible relation between the cilioretinal artery obstruction and the previous scleral reinforcement surgery is postulated based on two proposed mechanisms.

Combined radiotherapy and medical immunosuppression in the management of thyroid eye disease.

Although systemic steroids or orbital radiotherapy are effective in limiting the inflammatory response in thyroid eye disease (TED), there are reports of over 70% of treated patients requiring subsequent rehabilitative surgery: either orbital decompression or strabismus correction. This study investigated whether combined immunosuppression with primary orbital radiotherapy together with azathioprine and low-dose prednisolone, applied early in the active disease state, was more effective in treating TED. Forty consecutive patients with active TED were recruited. Orbital MRI (STIR sequence) was used to assess disease activity. Median duration of symptoms was 1.0 year. Subjects were treated with bilateral orbital radiotherapy (20 Gy in 10 fractions) and oral prednisolone and azathioprine. Pre- and post-treatment activity was measured clinically, including uniocular field of fixation, Mourits score and total eye score, until TED became inactive off all treatment. Before treatment, 15 subjects had signs of dysthyroid optic neuropathy, 35 had significant motility restriction and 38 had marked soft tissue signs. On average TED became inactive after 1.2 years (SD 0.7) of immunosuppression, and treatment was well tolerated. One patient required subsequent cosmetic orbital decompression, 6 had successful strabismus surgery and 13 required minor cosmetic lid surgery. Compared with previously reported treatment regimes we think that combined orbital radiotherapy and medical immunosuppression is far more effective than either treatment alone in the management of active TED, and led to fewer side effects of high-dose steroids. In particular there was more than a four-fold reduction in the requirement for orbital decompression and strabismus surgery.

Deficiencies in calculation and applied mathematics skills in pediatrics among primary care interns.

OBJECTIVE: To discover how well new house officers in primary care residency programs perform the mathematical calculations necessary to function effectively in pediatric and nursery settings. DESIGN: Criterion-referenced survey examination testing unit conversion, fluid and rehydration management, and drug-dosing skills. SETTING: Five primary care residences in family practice and pediatrics at urban and community campus sites in Illinois. PARTICIPANTS: Twenty-three family practice residents and 11 pediatric residents tested during residency orientations sessions or in conferences during the first 3 months of training. INTERVENTIONS: None. RESULTS: The mean score for all residents was 42%. Pediatric residents (mean score, 57.8%) performed significantly better than family medicine residents (mean score, 34.4%) (P = .002). Conversion from conventional to metric units was more difficult for family practice residents, but pediatric residents also made errors. Pediatric residents were significantly better than family medicine residents at calculation of fluid maintenance requirements (P < .05). Only 5 of 34 residents wrote acceptable fluid orders. Nutritional and drug therapy calculations showed fewer mathematical errors, but neither group routinely wrote medical orders that specified the drugs or formula, concentration, volume required per dose or feeding, route of administration, dosing interval, and duration of therapy. CONCLUSIONS: The potential for serious clinical errors caused by faculty calculation of dosage by house staff officers is high. New residents should have their orders for fluids and drugs double-checked by senior personnel early in their training. Residency programs should provide remedial skills training for house officers with deficiencies in applied mathematics. The medical school faculty needs to assess students' competence in mathematics before allowing independent clinical responsibility.

Magnetic resonance imaging in thyroid eye disease.

We examined 25 patients with thyroid eye disease, using both the STIR (Short Tau Inversion Recovery) sequence and cine MRI techniques. A number of characteristic features can be seen on the cine MRI. There is muscle enlargement with restriction of movement and, in the burnt-out phase of the disease, reduced elasticity of the muscles is manifest as their failure to stretch on eye movement. This is in contrast to the active phase of the disease, where although the muscles are enlarged, muscle stretching is clearly visible. The STIR sequence gives an assessment of muscle water content, and hence a high signal is seen in active disease. Combining these techniques is useful in assessing the level of disease activity in thyroid eye disease, and helps in planning further management.