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S F Barrington

Publications and source records attributed to S F Barrington.

At least 37 records · Page 2Linked to original sources
PubMed1998

Clinical value of "ictal" FDG-positron emission tomography and the routine use of simultaneous scalp EEG studies in patients with intractable partial epilepsies.

PURPOSE: EEG is widely used during positron emission tomography (PET) to confirm the interictal state of the patient and assist in scan interpretation when a seizure occurs. Ictal scans usually reflect mixed interictal-ictal-postictal metabolic activity as seizures are brief in comparison to the 30-min uptake period of the tracer. We wished to determine whether routine EEG is justified and if seizures commonly affect the diagnostic information of the PET scan. METHODS: We examined the PET scans of 6 of 236 outpatients with intractable epilepsy with clinical and electrical evidence of a seizure during tracer uptake. We performed semi-quantitative analysis in 2 patients who had "ictal" and control interictal scans. RESULTS: Patients with single seizures lasting 23 s to 4 min [four complex partial seizures (CPS) and one absence seizure (AS)] had focal hypometabolism concordant with results of other investigations. One patient with complex partial status had irregular cortical uptake and focal hypometabolism, but the site of the ictal focus could not be confirmed. CONCLUSIONS: In this group of patients, seizures occurred infrequently during tracer uptake. The interpretation of the PET scan when single seizures occurred did not appear to be influenced by the continuous scalp EEG (CSEEG) recordings. The value of routine CSEEG in outpatients treated with medication should be reappraised, with potential cost savings. In rare circumstances in which a true ictal study occurs (complex partial status, epilepsia partialis continua, and repetitive CPS), PET scanning may be inconclusive and repeat interictal scanning should be pursued.

Adolescent↗
PubMed1998

Technetium-99m-labeled HL91 to identify tumor hypoxia: correlation with fluorine-18-FDG.

UNLABELLED: Technetium-99m HL91 is a potential agent for imaging hypoxic tissue in vivo. A pilot evaluation using a prototype formulation assessed efficacy in tumor imaging and compared results with 18F-fluorodeoxyglucose (FDG) PET. METHODS: Ten patients with malignant tumors were included. Tumors included carcinoma of the bronchus (n = 3), carcinoma of the thyroid (n = 2), lymphoma (n = 2), soft tissue sarcoma (n = 1), carcinoid (n = 1) and carcinoma of the breast (n = 1). Whole-body planar scans and localized SPECT scans were performed at 1 and 4 hr postinjection of 600 MBq 99mTc HL91. Half-body and localized emission/transmission 18F-FDG PET scans were performed 60 min postinjection 370 MBq 18F-FDG in eight patients. Lesion-to-normal tissue background ratios were measured for all 99mTc HL91 and 18F-FDG PET scans and percentage uptake and standardized uptake values measured for 99mTc HL91 and 18F-FDG PET, respectively. RESULTS: Technetium-99m HL91 showed visible uptake into the tumor area in all seven studies where the tumor was clearly identified by 18F-FDG PET; 99mTc HL91 uptake was not detected in one study (carcinoid) in which 18F-FDG was weakly positive. Two further tumors, in which PET correlation was not available, showed accumulation of 99mTc HL91. In two 99mTc HL91 studies, abnormality was apparent only on SPECT images. Lesion-to-normal tissue background ratios for 99mTc HL91 ranged from 1.22/2.53 at 1 hr and 1.33/2.89 at 4 hr on planar images and 1.23/5.2 and 1.67/14.6 on SPECT images, respectively. CONCLUSION: In this study, the use of 99mTc HL91 resulted in uptake in the majority of malignant tumors identified by 18F-FDG-PET. Technetium-99m HL91 exhibits good imaging characteristics, with imaging at 4 hr providing good lesion-to-normal tissue background ratios, that are further enhanced by SPECT.

Aged↗
PubMed1997

Pentavalent 99Tcm-DMSA imaging in patients with bone metastases.

Pentavalent 99Tcm-dimercaptosuccinic acid (99Tcm-(V)DMSA) has an established role in imaging medullary thyroid carcinoma. There have been case reports of uptake in bone metastases. Our aims were to compare 99Tcm-(V)DMSA with 99Tcm-hydroxymethylene diphosphonate (99Tcm-HDP) in bone metastases, to assess its value in imaging of bone metastases, and to assess the prospects of the beta-emitting analogues 186/188Re-(V)DMSA as palliative agents for painful bone metastases. Ten patients confirmed by a 99Tcm-HDP bone scan to have bone metastases secondary to carcinoma of the prostate, lung or breast were injected with 99Tcm-(V)DMSA (600 MBq). Whole-body scans acquired at 3 and 24 h were compared with the 99Tcm-HDP bone scans. 99Tcm-(V)DMSA showed high soft tissue background, kidney retention and avid uptake in most bone metastases: 86% of bone lesions identified on bone scans were detected with 99Tcm-(V)DMSA. The lesion-to-normal ratios were comparable to or lower than those for 99Tcm-HDP at 3 h, but increased by 24 h. Instances of abnormal uptake in liver, primary lung tumour, lymph nodes and pleural effusion were observed. We conclude that 99Tcm-(V)DMSA is a tracer for bone metastases (with lower sensitivity than 99Tcm-HDP) and soft tissue tumours. If 186/188Re-(V)DMSA behave similarly, they may find use in therapy for soft tissue tumours and bony metastases.

Bone Neoplasms↗
PubMed1997

A study of the effects of sumatriptan on myocardial perfusion in healthy female migraineurs using 13NH3 positron emission tomography.

Sumatriptan, a 5-HT1D receptor agonist, is believed to alleviate migraine attacks by extracerebral vasoconstriction. Chest pain associated with myocardial ischemia may occur after sumatriptan administration. We investigated the effect of a single 6-mg subcutaneous dose of sumatriptan on myocardial perfusion (MP) as measured by 13NH3 positron emission tomography (PET) in a randomized, double-blind, placebo-controlled, crossover trial at the Clinical PET Centre, Guy's and St. Thomas' Hospitals, London. Nineteen volunteer female migraineurs, age range 33 to 62 years, at low risk for ischemic heart disease were included. All bad undergone previous treatment with oral or intravenous sumatriptan. Patients were recruited by advertisement and referral from local neurology specialists. Each volunteer underwent two scanning sessions. On each occasion, a baseline dynamic 13NH3 PET scan was acquired followed by a 13NH3 PET scan 10 minutes after subcutaneous injection of placebo or 6 mg of sumatriptan. Regional MP was measured in five myocardial regions using the Patlak system of image analysis. The mean % change from baseline (+/-SD) in global MP after placebo was +9.5% +/- 18.0 and after sumatriptan was +6.6% +/- 18.8 (repeated measures ANOVA for treatment effect p = 0.56). There were no significant differences in MP changes from baseline observed in any of the five myocardial regions (treatment p = 0.32 to 0.84). These data suggest that in healthy female migraineurs, a single 6-mg subcutaneous dose of sumatriptan does not cause a significant change in regional or global myocardial perfusion.

Adult↗
PubMed1997

PET scanning and the human immunodeficiency virus-positive patient.

UNLABELLED: The use of PET scanning in patients with human immunodeficiency virus infection and fever of unknown origin, confusion and/or weight loss was investigated. METHODS: Eighty patients were examined using PET. Fifty-seven patients had half-body scans with [18F]fluorodeoxyglucose (FDG), and 23 patients had brain studies performed with FDG. Fourteen patients also had [11C]methionine studies (2 chest, 1 abdomen and 11 brain) performed. RESULTS: Thirteen patients with lymphoma had the extent of the disease clearly identified in both nodal and extranodal sites. Patients with a variety of infections (Cryptococcus neoformans, Pseudomonas aeruginosa, Mycobacterium tuberculosis and Mycobacterium avium intracellulare) had disease localized for appropriate biopsy or sampling procedures. A half-body FDG-PET scan had a sensitivity of 92% and a specificity of 94% for localization of focal pathology that needed treatment. High uptake of FDG (greater than liver) had a positive predictive value for pathology needing treatment of 95%. FDG brain studies showed that 16 patients with CD4 T-lymphocyte counts less than 200 cells/ml had reduced cortical uptake compared with that in basal ganglia. FDG scans were abnormal in all 19 patients with focal space occupying lesions identified by magnetic resonance scans. The standardized uptake values (SUVs) over cerebral lesions due to toxoplasma were in the range of 0.14-3.7 (13 patients) and due to lymphoma were in the range of 3.9-8.7 (6 patients). Three more patients with progressive multifocal leukoencephalopathy had SUVs in the range of 1.0-1.5 over the lesions. Another patient had a low-grade oligodendroglioma (SUV = 2.9). Carbon-11-methionine uptake also was high in patients with cerebral lymphoma but did not add to the discrimination between toxoplasmosis and lymphoma in these patients obtained with the FDG scan. CONCLUSION: In hospitals with access to PET facilities, FDG scanning allows the rapid evaluation of the whole body, including the brain, of patients with human immunodeficiency virus infection, with a report potentially available within 4 hr of injection. Sites of infection and tumor were identified, and discrimination between cerebral pathologies was possible.

AIDS-Related Opportunistic Infections↗
PubMed1996

Radiation dose rates from patients receiving iodine-131 therapy for carcinoma of the thyroid.

Patients treated with radioiodine present a radiation hazard and precautions are necessary to limit the radiation dose to family members, nursing staff and members of the public. The precautions advised are usually based on instantaneous dose rates or iodine retention and do not take into account the time spent in close proximity with a patient. We have combined whole-body dose rate measurements taken from 86 thyroid cancer patients after radioiodine administration with published data on nursing and social contact times to calculate the cumulative dose that may be received by an individual in contact with a patient. These dose estimates have been used to calculate restrictions to patients behaviour to limit received doses to less than 1 mSv. We have also measured urinary iodide excretion in 19 patients to estimate the potential risk from the discharge of radioiodide into the domestic drainage system. The dose rate decay was biexponential for patients receiving radioiodine to ablate the thyroid after surgery (the ablation group, A) and monoexponential for these receiving subsequent treatments for residual or recurrent disease (the follow-up group, FU). The faster clearance in the follow-up patients generally resulted in less stringent restrictions than those advised for ablation patients. For typical activities of 1850 MBq for the ablation patients and 3700 MBq or 7400 MBq for the follow-up patients, the following restrictions were advised. Patients could travel in a private car for up to 8h on the day of treatment (for an administered activity of 1850 MBq in group A) or 4 and 2h (for activities of 3700 or 7400 MBq in group FU) respectively. Patients should remain off work for 3 days (1850 MBq/group A) or 2 days (up to 7400 MBq/group FU). Partners should avoid close contact and sleep apart for 16 days (1850 MBq/group A) or 4-5 days (3700 or 7400 MBq/group FU). Contact with children should be restricted according to their age, ranging from 16 days (1850 MBq/group A) or 4-5 days (3700 or 7400 MBq in group FU) for younger children, down to 10 days (1850 MBq/group A) or 4 days (up to 7400 MBq/group FU) for older children. The cumulative dose to nursing staff for the week after treatment was dependent on patient mobility and was estimated at 0.08 mSv for a self-caring patient to 6.3 mSv for a totally helpless patient (1840 MBq/group A). Corresponding doses to nurses looking after patients in group FU were 0.18-12.3 mSv (3700 MBq) or 0.36-24.6 mSv (7400 MBq). Sensible guidelines can be derived to limit the dose received by members of the public and staff who may come into contact with cancer patient treated with radioiodine to less than 1 mSv. The rapid clearance of radioiodine in patients treated on one or more than one occasion means that therapy could be administered at home to selected patients with suitable domestic circumstances. In most cases the restriction times, despite the high administered activities, are less than those for patients treated for thyrotoxicosis. The concentration of radioiodide in domestic drainage systems should not pose a significant risk.

Adult↗
PubMed1996

Assessment of changes in dual-energy X-ray absorptiometry performance following a system upgrade.

System upgrades are a constant feature of many highly technical specialties and are normally assumed to have a negligible effect on patient data. We report on the assessment of an upgrade made to a Norland XR-26 dual-energy X-ray absorptiometry (DXA) system. The upgraded version (2.3) consisted of new hip positioning aids, hip image analysis software and updates to the normal ranges. Measurements of femoral neck and trochanteric bone mineral density correlated well between versions (r = 0.969 and r = 0.971), those for femoral neck and trochanteric bone mineral content less well (r = 0.956 and r = 0.911), and Ward's triangle values and femoral neck area measurements were poorly correlated (r = 0.719-0.881). The upgrade was claimed to improve precision while reducing analysis and imaging time. Improved precision was not demonstrated, with good precision found both before and after the upgrade. Correlation between femoral neck Z-scores were good for the European normal range (r = 0.970), but unacceptable for the UK range (r = 0.769). These correlations were not close enough to allow patients scanned with the old version to be followed up with scans using the upgrade. The upgrade was, however, preferred for new attenders because of the improved speed and automation of hip analysis, without loss of precision. The most important implication in terms of patient management was the change made to the UK normal range, which had a very large effect on the number of patients deemed to be at risk from osteoporosis. It is essential that any upgrade introduced to an existing DXA system is carefully evaluated, since it may affect system performance and patient results.

Absorptiometry, Photon↗
PubMed1996

Focal abnormalities detected by 18FDG PET in epileptic encephalopathies.

A prospective study of 32 children with epileptic encephalopathies 12 years or younger revealed a high incidence of focal cortical metabolic defects on 18-fluorodeoxyglucose positron emission tomography (PET) not suspected from clinical, EEG, or magnetic resonance imaging findings. PET scans were normal in all five children with typical de novo Lennox-Gastaut syndrome but showed cortical metabolic abnormalities in three out of four with atypical de novo Lennox-Gastaut syndrome, five out of six with Lennox-Gastaut syndrome following infantile spasms, six out of eight with severe myoclonic epilepsy in infancy, one out of two with epilepsy with myoclonic-astatic seizures, and four out of six with an unclassified epileptic encephalopathy. This suggests that some children with epileptic encephalopathies previously thought to have primary generalised seizures or seizures due to multifocal pathology may have unifocal cortical origin for their seizures. Such an origin may be amenable to surgery.

Child↗
PubMed1996

Speech-related visualization of laryngeal muscles with fluorine-18-FDG.

UNLABELLED: This study describes the physiological uptake of 18F-fluoro-2-deoxyglucose (FDG) by the laryngeal muscles secondary to activation of the patient's vocal folds and related laryngeal muscles during speech. METHODS: Twenty-four patients undergoing routine PET scans were randomized into two groups to ascertain the relationship between FDG uptake in the laryngeal region and speech. One group was assigned to talk and the other group remained silent during the injection and uptake period of FDG. RESULTS: FDG uptake in the laryngeal muscles in the scans was correlated with speech. Patients who spoke continually during the uptake period had high-grade FDG uptake, those who spoke intermittently had low-grade uptake and those who remained silent had no detectable increase in FDG uptake in the region of the larynx. CONCLUSION: The relationship between the degree of laryngeal muscle uptake and speech provides useful information to allow differentiation of physiological from pathological uptake in the neck.

Adult↗
PubMed1996

Skeletal muscle uptake of fluorine-18-FDG: effect of oral diazepam.

UNLABELLED: We have observed a pattern of symmetrically increased uptake of [18F]fluorodeoxyglucose (FDG) in the neck and thoracic paravertebral regions of several patients referred for whole-body PET. The distribution is suggestive of uptake in contracting skeletal muscle in tense patients. METHODS: To test this hypothesis, six successive patients who exhibited this pattern of uptake underwent rescanning using an identical imaging protocol but with oral diazepam before injection of FDG. RESULTS: The increased neck and paravertebral uptake was significantly reduced or abolished with diazepam, confirming the supposition that this increased neck and paravertebral uptake represents a normal variant of muscle uptake. CONCLUSION: Oral diazepam, given before the uptake period can be helpful in such patients to exclude the masking of potential abnormalities by this characteristic pattern of FDG uptake.

Adult↗
PubMed1995

Staging of Burkitt's lymphoma and response to treatment monitored by PET scanning.

Positron emission tomography (PET) is an imaging technique using biological tracers (18-fluorine fluorodeoxyglucose (FDG)), whose uptake into tumour cells is increased. Previous studies carried out in patients with lymphoma have shown that PET is an accurate method of staging disease and that a high pre-treatment FDG uptake that is abolished by the end of chemotherapy is associated with a good clinical response. This case report demonstrates that clinical PET scanning can be especially useful in staging patients with lymphoma in whom there is extensive extranodal and marrow involvement, and that PET can follow changes in tumour viability over a very short time span.

Adult↗
PubMed1995

Ventilation and perfusion lung imaging--which nebulizer?

Three commercially available 99Tcm-diethylenetriamine pentaacetate (99Tcm-DTPA) aerosol delivery nebulizers for lung ventilation imaging were investigated. Two were air-jet systems, 'Optimist' (Medicaid) and 'Microcirrus' (Amersham), and one was an ultrasonic device (Europlus). Altogether, 112 consecutive patients were scanned, 37 using the Optimist, 40 using the Microcirrus and 35 the Europlus. The age mix, FEV1, FVC and PEFR measurements of the patients in each group were similar. Each contained a proportion of patients with poor respiratory function, with PEFR rates ranging from 30 to 582 l min-1 for patients studied with all systems. Ease of use, image quality and cost were evaluated as well as radioactive and microbiological contamination. The Optimist system gave the best combination of image quality and cost, and was associated with the lowest level of radioactive contamination. It also proved the most popular. Airborne contamination for all nebulizers was lower than previously reported and was largely dependent on patient compliance. With poorly compliant patients, the contamination levels are sufficient to warrant an extraction device. There was no evidence of bacterial contamination of the nebulizers or tubing on repeated use over 5 days.

Forced Expiratory Volume↗
PubMed1995

A survey of dual-energy X-ray absorptiometry (DEXA) normal reference ranges used within the UK and their effect on patient classification.

Differences between dual-energy X-ray absorptiometry (DEXA) normal ranges can lead to patients being characterized as osteoporotic using one range and normal using another. To investigate the diversity of normal ranges used within the UK, a survey of all DEXA sites was carried out with a 60.6% response rate. The effect of the different ranges was evaluated by translating each range to an equivalent range for a Norland XR-26 system and applying the ranges to stratify a representative sample of over 1000 patients into grades of bone density based on percentages of age-matched mean BMD, Z-scores and T-scores. The effect of femoral neck and P/A spine L2-L4 regions was considered both separately and jointly. Large differences between the normal ranges were apparent, which resulted in the classification of the number of patients with a Z-score of less than -2.0 varying by a factor of more than 20 for the femoral neck and more than 3 for the spine. The number of patients defined as osteoporotic by a T-score less than -2.5 varied from none to over one-third of patients for the hip and by a factor of almost 3 for the spine. The exclusion criteria used for construction of the normal ranges varied markedly with none constructed using population-based sampling. Smoothing of normal ranges was carried out by DEXA manufacturers, while local normal ranges made use of raw unprocessed data. There is reason to question the validity of such processing. We recommend the construction of a unified UK normal range applicable to all UK DEXA systems in order to harmonize patient management and care.

Absorptiometry, Photon↗
PubMed1995

Home reporting for the nuclear clinician?

The computer-based 'home office' is becoming a widely accepted mode of operation for modern businesses. It is implausible to believe that a nuclear medicine department can be covered permanently at a distance by a single physician, but it should be possible to provide cover for colleagues during sickness or at night or weekends. We have used a 486 PC with a high-resolution screen and software provided by LINK Medical Ltd to obtain images from hospital sites using a modem link to ADAC, Bartec and Nuclear Diagnostic SUN workstations. The data were transferred via standard telephone lines to the homes of two of the authors. During a trial period lasting several months, 60 lung scans, 20 bone scans, 1 gastrointestinal bleeding study, 4 leukocyte scans, 5 bone tomograms, 9 renograms, 6 myocardial perfusion tomograms and 2 gated cardiac studies were transferred. The system allowed transfer of a 128 x 128 eight-view lung scan to be completed in approximately 2 min. The program on the PC allowed alteration of individual image contrast, image rotation, cine display and a variety of colour scales to enhance image interpretation. A system to transfer chest X-rays has been developed and typical transfer times are approximately 3.5 min. Within the viewing protocol on the PC, a reporting window was available with the ability to fax the report directly to the hospital. The system allowed consultants who live at a distance from their nuclear medicine departments to provide cover and is now used as an integral part of our out-of-hours service. The system also allows cover of satellite units or to provide cover for junior staff at night or weekends.

Computer Communication Networks↗