The association between epidural labour analgesia and postpartum depression: a randomised controlled trial

There is conflicting evidence regarding the association between epidural labour analgesia and risk of postpartum depression. Most previous studies were observational trials with limited ability to account for confounders. We aimed to determine if epidural analgesia was associated with a significant change in the incidence of postpartum depression in this randomised controlled trial. We enrolled women aged 21-50 years old with a singleton fetus ≥ 36 weeks gestation. Patients were advised regarding available labour analgesic modalities during enrolment (epidural block; intramuscular pethidine; nitrous oxide; or intravenous remifentanil). On request for analgesia, patients were offered the modality that they had been allocated randomly to first. Blinded investigators recorded patient and obstetric characteristics within 24 h of delivery and assessed for postpartum depression at 6-10 weeks following delivery using the Edinburgh Postnatal Depression Scale (score ≥ 13 considered positive for postpartum depression). The modified intention-to-treat population consisted of all patients who received any form of labour analgesia, while per-protocol consisted of patients who received their randomised modality as their first form of labour analgesia. Of 881 parturients allocated randomly (epidural n = 441, non-epidural n = 440), we analysed 773 (epidural n = 389, non-epidural n = 384); 62 (15.9%) of women allocated to epidural group developed postpartum depression compared with 65 (16.9%) women allocate to the non-epidural group. There were no significant differences in the incidence of postpartum depression between the two groups (adjusted risk difference (95%CI) 1.6 (-3.0-6.3%), p = 0.49). Similar results were obtained with per-protocol analysis (adjusted risk difference (95%CI) -1.0 (-8.3-6.3%), p = 0.79). We found no significant difference in the risk of postpartum depression between patients who received epidural labour analgesia and those who utilised non-epidural analgesic modalities.

Machine learning accurately quantifies epicardial adipose tissue from non-contrast CT images in coronary artery disease

Funding Acknowledgements

Type of funding sources: Other. Main funding source(s): Industry Alignment Fund – Pre-positioning Programme

Background

Epicardial adipose tissue (EAT) is the visceral fat deposit within the pericardium that surrounds the heart and the coronary arteries. EAT volume measured from non-contrast CT (NCCT) has been demonstrated to be significantly associated with adverse cardiovascular risk,1 particularly in patients with coronary artery disease.2 However, routine measurement of EAT volume is still challenging in clinical practice, as it is a tedious manual process and prone to human error.

Purpose

We aimed to develop a fully automated AI toolkit (i.e., AI EAT) for the quantification of EAT from routine NCCT scans and assess its performance in reference to clinical ground truth.

Methods

This is a multicenter study which performs CT scans in 5000 Asian Admixture patients (APOLLO study NCT05509010). In the current stage of this study, NCCT data analysis were conducted in 551 patients with 26,037 images. AI EAT was developed via a novel deep learning framework using an ensemble region-based UNet. The region-based UNet uses 2 component UNet models to perform segmentation of pericardium at the apex region and non-apex region (middle and basal). EAT volume was obtained by automated thresholding of the voxels (-190 to -30 Hounsfield Unit) within the pericardium (Figure 1). The network was trained in 501 patients with 23,712 NCCT images and tested in 50 patients with 2,325 NCCT images. The performance of AI EAT was evaluated with respect to clinical ground truth using Dice similarity coefficient (DSC), Pearson correlation, and Bland-Altman analysis.

Results

The AI EAT quantification process took less than 10 seconds per subject, compared with 20-30 minutes for expert readers. Compared to clinical ground truth, our AI EAT achieved a DSC of 0.96±0.01 and 0.91±0.02 for pericardium and EAT segmentations, respectively. There was strong agreement between the AI EAT and clinical ground truth in deriving the EAT volume (r=0.99, P<0.001) with minimal error of 7±5%.

Conclusion

End-to-end deep learning system accurately quantifies epicardial adipose tissue in standard NCCT images without manual segmentation.

P1925Machine learning versus classic electrocardiographic criteria for left ventricular hypertrophy in a young pre-participation cohort: results from the SAFE protocol study

Background/Introduction

Classic electrocardiographic (ECG) criteria for left ventricular hypertrophy (LVH) have been well studied in Western populations, particularly in hypertensive patients. However, their utility in Asian populations is not well studied, and their applicability to young pre-participation cohorts is unclear. We sought to evaluate the performance of classical criteria against that of machine learning models.

Aims

We sought to evaluate the performance of classical criteria against the performance of novel machine learning models in the identification of LVH.

Methodology

Between November 2009 and December 2014, pre-participation screening ECG and subsequent echocardiographic data was collected from 13,954 males aged 16 to 22, who reported for medical screening prior to military conscription.

Final diagnosis of LVH was made on echocardiography, with LVH defined as a left ventricular mass index >115g/m2. The continuous and binary forms of classical criteria were compared against machine learning models using receiver-operating characteristics (ROC) curve analysis. An 80:20 split was used to divide the data into training and test sets for the machine learning models, and three fold cross validation was used in training the models. We also compared the important variables identified by machine learning models with the input variables of classical criteria.

Results

Prevalence of echocardiographic LVH in this population was 0.91% (127 cases). Classical ECG criteria had poor performance in predicting LVH, with the best predictions achieved by the continuous Sokolow-Lyon (AUC = 0.63, 95% CI = 0.58–0.68) and the continuous Modified Cornell (AUC = 0.63, 95% CI = 0.58–0.68). Machine learning methods achieved superior performance – Random Forest (AUC = 0.74, 95% CI = 0.66–0.82), Gradient Boosting Machines (AUC = 0.70, 95% CI = 0.61–0.79), GLMNet (AUC = 0.78, 95% CI = 0.70–0.86). Novel and less recognized ECG parameters identified by the machine learning models as being predictive of LVH included mean QT interval, mean QRS interval, R in V4, and R in I.

ROC curves of models studies

Conclusion

The prevalence of LVH in our population is lower than that previously reported in other similar populations. Classical ECG criteria perform poorly in this context. Machine learning methods show superior predictive performance and demonstrate non-traditional predictors of LVH from ECG data. Further research is required to improve the predictive ability of machine learning models, and to understand the underlying pathology of the novel ECG predictors identified.

Hyoscine butylbromide administered at the cecum increases polyp detection: a randomized double-blind placebo-controlled trial

BACKGROUND AND STUDY AIMS

Removal of colonic polyps prevents progression of colonic neoplasia. Miss rates of polyps range from 5 % to 32 %. The effect of colonic contractility on polyp detection has not been studied adequately. Hyoscine butylbromide results in colonic spasmolysis and may improve polyp detection.

PATIENTS AND METHODS

Patients undergoing colonoscopy for standard indications were included and randomized to receive either 20  mg hyoscine butylbromide or placebo at cecal intubation. Operators were blind to the intervention. Data on indication, preparation, sedation, colonoscope type, times of insertion/withdrawal, polyps, and failure were recorded. The primary end point was the number of polyps detected per patient. Secondary endpoints were adenoma detection rate and polyp detection rate.

RESULTS

A total of 303 patients received hyoscine butylbromide and 298 received placebo. More polyps per patient were identified in the hyoscine group than in the placebo group (0.91 vs. 0.70; P = 0.044). Adenoma detection rate and polyp detection rate were higher in the hyoscine arm but not significantly different (27.1 % vs. 21.8 % [P = 0.13] and 43.6 % vs. 36.6 % [P = 0.08], respectively). After adjusting for confounding variables, the odds of detecting any polyp were 1.56 higher in the hyoscine than the placebo group (95 % confidence interval [CI] 1.09 - 2.21, P = 0.014). The adjusted odds of detecting any adenoma were 1.62 higher in the hyoscine group compared with the placebo group (95 %CI 1.09 - 2.42, P = 0.017). There were no differences in baseline characteristics between the groups. No adverse colonoscopy-related events were recorded. One patient experienced transient tachycardia without sequelae.

CONCLUSIONS

Hyoscine butylbromide administered at the cecum aids polyp detection. Further studies are required to determine the contribution of colonic spasm to polyp miss rates.

New techniques in imaging in Barrett's esophagus

The presence of dysplasia in patients with Barrett's esophagus identifies who is at increased risk for the development of esophageal adenocarcinoma and who may most benefit from intervention. Several technologies have emerged as potent tools to identify subtle or occult neoplasia in the gastrointestinal tract. Detailed inspection of the mucosa with high resolution white light endoscopy is the most critical tool to detect subtle neoplasia. This review also chromoendoscopy, narrow band imaging, autofluorescence imaging, optical coherence tomography, confocal laser endomicroscopy, and spectroscopy in the context of detection of neoplasia in Barrett's esophagus.

Ministry of health clinical practice guidelines: screening of cardiovascular disease and risk factors

The Ministry of Health (MOH) publishes clinical practice guidelines on Screening of Cardiovascular Disease and Risk Factors to provide doctors and patients in Singapore with evidence-based guidance on the screening of cardiovascular disease and risk factors. This article reproduces the introduction and executive summary (with recommendations from the guidelines) from the MOH clinical practice guidelines on Screening of Cardiovascular Disease and Risk Factors, for the information of readers of the Singapore Medical Journal. Page numbers mentioned in the reproduced extract refer to the full text of the guidelines, which are available from the Ministry of Health website (http://www.moh.gov.sg/mohcorp/publications.aspx?id=25776). The recommendations should be used with reference to the full text of the guidelines. Following this article are multiple choice questions based on the full text of the guidelines.

Impact of surgical ventricular restoration on ventricular shape, wall stress, and function in heart failure patients

Surgical ventricular restoration (SVR) was designed to treat patients with aneurysms or large akinetic walls and dilated ventricles. Yet, crucial aspects essential to the efficacy of this procedure like optimal shape and size of the left ventricle (LV) are still debatable. The objective of this study is to quantify the efficacy of SVR based on LV regional shape in terms of curvedness, wall stress, and ventricular systolic function. A total of 40 patients underwent magnetic resonance imaging (MRI) before and after SVR. Both short-axis and long-axis MRI were used to reconstruct end-diastolic and end-systolic three-dimensional LV geometry. The regional shape in terms of surface curvedness, wall thickness, and wall stress indexes were determined for the entire LV. The infarct, border, and remote zones were defined in terms of end-diastolic wall thickness. The LV global systolic function in terms of global ejection fraction, the ratio between stroke work (SW) and end-diastolic volume (SW/EDV), the maximal rate of change of pressure-normalized stress (dσ*/dt(max)), and the regional function in terms of surface area change were examined. The LV end-diastolic and end-systolic volumes were significantly reduced, and global systolic function was improved in ejection fraction, SW/EDV, and dσ*/dt(max). In addition, the end-diastolic and end-systolic stresses in all zones were reduced. Although there was a slight increase in regional curvedness and surface area change in each zone, the change was not significant. Also, while SVR reduced LV wall stress with increased global LV systolic function, regional LV shape and function did not significantly improve.

The evolving role of molecular imaging for coronary artery disease: where do we stand today?

The landscape of cardiac imaging is changing rapidly. There are promising new developments in molecular imaging on the horizon. It is likely that nuclear cardiology will continue to play an important role in the evaluation of CAD, but that role must evolve to meet clinical needs, competing technologies and the increasing emphasis on ensuring that imaging adds value and improves outcomes. This review offers some suggestions on the optimal role nuclear imaging can play vis-à-vis alternative options such as CT, but more data are needed before definitive recommendations can be made. Randomised trials comparing different diagnostic strategies can and should be performed to strengthen the foundations of clinical practice in nuclear cardiology. An evidence-based approach to imaging is here to stay.

Prevalence of significant extracoronary findings on multislice CT coronary angiography examinations and coronary artery calcium scoring examinations

The purpose of the study was to review the prevalence of significant extracoronary findings in patients who underwent multislice CT coronary angiography examinations and coronary artery calcium scoring examinations. We reviewed the reports of 295 consecutive patients who underwent multislice CT coronary angiography examinations and 140 consecutive patients who had separate coronary calcium scoring examinations from September 2004 to March 2006 in our department's radiology information system. Additional investigations carried out as a result of these findings were also recorded. Fifty-six (19%) out of 295 patients had significant extracoronary findings on coronary CT angiography requiring clinical or radiological follow up. There were 60 significant extracoronary findings. These included 24 patients who had pulmonary abnormalities, 4 who had mediastinal abnormalities, 20 who had upper abdominal abnormalities and 5 who had non-coronary cardiac abnormalities. Three patients had both pulmonary and upper abdominal abnormalities. Eleven (8%) out of 140 patients had significant pulmonary, breast, mediastinal, upper abdominal and cardiac abnormalities on coronary artery calcium scoring examinations, yielding a total of 12 significant findings. In our experience, 19% of the patients who underwent multislice CT coronary angiography and 8% of the patients who underwent coronary artery calcium scoring examinations had significant extracoronary findings requiring follow up. It is therefore imperative for the reporting physician to review the entire examination after the coronary arteries have been assessed. The prevalence of extracoronary findings on these examinations may be of significance, resulting in additional 'hidden costs' if widespread 'screening' is adopted.

Electrocardiographical case. Elderly man with acute breathlessness. Atrial tachycardia with variable AV conduction block and transient hyperkalaemia-induced aberrant conduction

A 67-year-old Chinese man presented to the emergency department with a history of abdominal bloating and shortness of breath. Initial electrocardiogram (ECG) showed atrial tachycardia (AT) with 2:1 atrioventricular (AV) conduction block. Six days after admission, he developed acute dyspnoea and confusion. Repeat ECG demonstrated a regular wide-complex tachycardia. Serum analysis revealed hyperkalaemia secondary to acute on chronic renal failure. Emergency treatment with intravenous calcium gluconate, 50% dextrose solution and short-acting insulin was instituted. The ECG promptly reverted to a narrow-complex AT with 2:1 AV conduction block. The diagnosis and treatment of AT are discussed.

Association analysis of endothelial nitric oxide synthase gene polymorphism with primary hypertension in a Singapore population

Vascular endothelial cells produce nitric oxide (NO), which contributes to the regulation of blood pressure and regional blood flow. Endothelial nitric oxide synthase (eNOS) gene polymorphisms are associated with coronary artery disease, but their linkage with primary hypertension is controversial. A total of 103 individuals with primary hypertension and 104 normotensive control subjects were studied in Singapore. The specific genotypes for G894T missense variant in exon 7, variable number tandem repeats (VNTR) in intron 4 (eNOS 4A/B/C) and T-786C in the promoter were isolated using allele-specific gene amplification and restriction fragment length polymorphism to examine the association of genotype and allelic frequency in both groups. Logistic regression analysis was also used to detect the association between genotypes and hypertension. Five genotypes of intron 4 VNTR (AA, AB, BB, AC and BC) were observed. Intron 4 B/B genotype was significantly associated with the hypertension group (P = 0.035), but disequilibrium of G894T and T-786C was absent between the two groups (P = 0.419 and P = 0.227), respectively. The overall distribution of allelic frequency differed significantly between the two groups, with four-repeat allele (4A) of intron 4 more frequent in the normotensive group than the hypertensive group (P = 0.019). Logistic regression analysis showed that intron 4 B/B genotype was significantly associated with systolic blood pressure of individuals with body mass index greater than 25 kg/m2 (P = 0.04). In conclusion, the eNOS 4 B/B genotype is a genetic susceptibility factor for primary hypertension in a Singapore population.

A case series of sotalol-induced torsade de pointes in patients with atrial fibrillation--a tale with a twist

INTRODUCTION

Sotalol is a potent antiarrhythmic often used in patients with atrial fibrillation. However, it has been associated with a risk of provoking other potentially dangerous arrhythmias, especially if used in high doses and in patients with uncorrected electrolyte imbalance or impaired renal and cardiac function.

CLINICAL PICTURE

We present 4 patients with atrial fibrillation treated with sotalol who developed torsade de pointes due to marked prolongation of the QT interval. While 1 patient had renal failure, all had normal left ventricular function. One patient had been treated with sotalol for more than 10 months before developing torsade de pointes precipitated by hypokalaemia, while another had tolerated sotalol for a 3-month period before the drug was discontinued, and only developed torsade de pointes when the drug was restarted 2 years later. Significantly, the doses used in all patients were relatively low, in contrast to most other reported cases where higher doses were used.

CONCLUSION

As with all antiarrhythmic therapy, these cases illustrate the need for close follow-up of patients treated with sotalol, even if relatively low doses are used. In addition, patients who had previously tolerated the drug well are still susceptible to its proarrhythmic effects.

Ethnic differences in acute myocardial infarction in Singapore

AIMS

We compare the myocardial infarction (MI) event and mortality rates among Chinese, Malay and Indian residents of Singapore.

METHODS

Residents, aged 20 to 64 years, with an MI event were identified from hospital discharge listings, postmortem reports, and the Registry of Births and Deaths. All pathology laboratories flagged patients with elevated creatine phosphokinase (CPK) levels. Modified MONICA (multinational monitoring of trends and determinants in cardiovascular disease) criteria were used for determining MI events.

RESULTS

From 1991 to 1999, 12 481 MI events were identified. Chinese patients were older and less likely to have typical symptoms or previous MI. Malays had the highest peak CPK level. Among all three ethnic groups, MI event and age-adjusted case-fatality rates declined. Compared with Chinese, MI event rates were >2-fold and >3-fold higher, and age-standardized coronary mortality rates were 2.4 and 3.0 higher times for Malays and Indians, respectively. Malays have the highest 3.1-year case-fatality, with an adjusted hazard ratio of 1.26 (95% confidence interval, 1.14 to 1.38) compared with Chinese.

CONCLUSION

We found strong ethnic differences in MI event, case-fatality and coronary mortality rates among the three ethnic groups in Singapore. While Indians have the greatest MI event rates, Malays have the highest case-fatality.

An outbreak of multidrug-resistant Salmonella enterica subsp. enterica serotype Typhimurium, DT104L linked to dried anchovy in Singapore

Multidrug-resistant Salmonella enterica subsp. enterica serotype Typhimurium DT104L was first reported in Singapore from mid-July to mid-October 2000. Salmonella strains isolated from clinical laboratories were submitted to a reference laboratory for serotyping, phage-typing and pulsed-field gel electrophoresis (PFGE) using XbaI restriction endonuclease. An epidemiological investigation was conducted to determine the source of infection and mode of transmission using a structured questionnaire. A total of 33 cases involving mainly infants and toddlers were detected in the 3-month long outbreak. The outbreak strain was of the R-type ACGSTSu, i.e. resistant to ampicillin, chloramphenicol, gentamicin, streptomycin, tetracycline and sulphonamide. PFGE showed all isolates had an indistinguishable pattern, indicating a common source of infection. Consumption of imported dried anchovy was found to be the vehicle of transmission after adjusting for all confounding variables in the case-control study using stepwise logistic regression (OR 25.6; 95% CI 3.9-167.9; P = 0.001). Imported dried seafood should be properly processed, packed, labelled, and thoroughly cooked to prevent transmission of multidrug-resistant S. Typhimurium.

Leopard syndrome

The Leopard syndrome is a complex of multisystemic congenital abnormalities characterised by lentiginosis, electrocardiographic conduction abnormalities, ocular hypertelorism, pulmonary stenosis, abnormalities of genitalia, retardation of growth and deafness (sensorineural). Hypertrophic cardiomyopathy, though not included in the mnemonic, is often associated. Although the Leopard syndrome is rare, it is important to recognise it since it can be associated with serious cardiac disease. It is advisable to follow up patients with Leopard syndrome for new onset of cardiac abnormalities and to monitor the progression of existing cardiac disease. We present a case report and review of the literature of this syndrome.

Giant coronary aneurysms with multiple vascular aneurysms: a rare manifestation of hyperhomocysteinemia

Hyperhomocysteinemia is associated with accelerated atherosclerosis, which leads to an increased incidence of premature vascular disease. Although multiple vascular aneurysms have been linked to hyperhomocysteinemia, coronary artery aneurysms have not. We report a case of giant coronary artery aneurysm associated with multiple peripheral vascular aneurysms in a patient with hyperhomocysteinemia.

Accuracy of the automated assessment of left ventricular function with gated perfusion SPECT in the presence of perfusion defects and left ventricular dysfunction: correlation with equilibrium radionuclide ventriculography and echocardiography

BACKGROUND

Gated single photon emission computed tomography (SPECT) with automated methods allows the quantitative assessment of left ventricular function and perfusion; however, its accuracy must be defined for patients with large earlier infarctions and severe rest perfusion defects, in whom the estimation of endocardial and epicardial borders might be more difficult, even with automated edge-detection techniques.

METHODS AND RESULTS

We prospectively compared the automated measurements of left ventricular ejection fraction (LVEF) and volumes from rest-injected gated Technetium 99m (Tc99m) perfusion SPECT with equilibrium radionuclide angiocardiography (ERNA) in 62 patients and the assessment of regional function with echocardiography in 22 patients. Forty-six patients had an earlier myocardial infarction (mean defect size, 34% of left ventricle; SD, 12.7%; range, 8% to 56%); 27 patients had large defects (> or = 20% of left ventricle; LVEF range, 8% to 75%). LVEF, as determined with Cedars-Sinai software (quantitative gated SPECT), correlated well with ERNA (r = 0.941; y = 1.003x + 1.15; P<.0001; SE of the estimate = 6.3%; mean difference -1.3% for LVEF) in the entire study population and in the subgroups of patients with an earlier infarction, severe defects, and large infarctions (> or = 20% of the left ventricle). A correlation existed between gated SPECT and ERNA volumes (r = 0.882, y = 1.040x - 14.7, P<.0001 for end-diastolic volume; r = 0.954, y = 1.147x - 13.9, P<.0001 for end-systolic volumes with the count-ratio technique), but with wider limits of agreement. The exact segmental score agreement between gated SPECT and echocardiography for regional function was 79.8% (281 of 352, kappa = 0.682).

CONCLUSIONS

Automated gated SPECT provides an accurate assessment of ejection fraction and regional function, even in the presence of an earlier myocardial infarction with large perfusion defects and significant left ventricular dysfunction.

Gated technetium-99m sestamibi for simultaneous assessment of stress myocardial perfusion, postexercise regional ventricular function and myocardial viability. Correlation with echocardiography and rest thallium-201 scintigraphy

OBJECTIVES

This study compares technetium-99m sestamibi (sestamibi) electrocardiographic (ECG) gated single-photon emission computed tomography (gated SPECT) and echocardiography for the evaluation of myocardial function and assesses the feasibility of single-injection, single-acquisition stress perfusion/rest function technetium-99m sestamibi-gated SPECT as an alternative to conventional stress/rest imaging for assessment of myocardial perfusion and viability.

BACKGROUND

Simultaneous assessment of stress perfusion and rest function is possible with gated SPECT acquisition of stress-injected technetium-99m sestamibi.

METHODS

Rest thallium-201 SPECT followed by stress sestamibi-gated SPECT (acquired 0.5 to 1 h after sestamibi injection) was performed in 58 patients. Echocardiography was performed immediately after or before gated SPECT in 43 of the patients. All studies were analyzed by semiquantitative visual scoring. Sestamibi-gated SPECT studies were read for stress perfusion and rest wall motion and thickening. Reversibility on sestamibi-gated SPECT was defined as the presence of a definite stress defect with normal or mildly impaired wall motion or thickening on gated SPECT:

RESULTS

There was high segmental score agreement between gated SPECT and echocardiography for wall motion (91%, kappa = 0.68, p < 0.001) and thickening (90%, kappa = 0.62, p < 0.001). Correlation for global wall motion (r = 0.98, p < 0.001) and thickening (r = 0.96, p < 0.001) scores between the two modalities was excellent. In 32 patients without previous myocardial infarction, there was excellent agreement for reversibility between stress sestamibi-gated SPECT and rest thallium-201/stress sestamibi (98%, kappa = 0.93, p < 0.01). However, in 26 patients with previous infarction, discordance between the two approaches was frequent, with 26% (20 of 78) of nonreversible defects by stress sestamibi-gated SPECT being reversible by rest thallium-201/stress sestamibi and 21% (23 of 112) of reversible defects by stress sestamibi-gated SPECT being nonreversible by rest thallium-201/stress sestamibi.

CONCLUSIONS

Gated SPECT of stress-injected sestamibi correlates well with echocardiographic assessment of regional function and thus adds information to perfusion SPECT: In patients without previous myocardial infarction, a single-injection stress perfusion/rest function approach using sestamibi-gated SPECT can substitute for conventional stress/rest myocardial perfusion imaging, adding a rest perfusion study only if there are nonreversible defects or consideration of attenuation artifacts. In patients with previous myocardial infarction, the gated SPECT approach does not replace the need for a rest perfusion study.

A quantitative phantom analysis of artifacts due to hepatic activity in technetium-99m myocardial perfusion SPECT studies

We have observed that filtered backprojection may cause artifactual decreased myocardial wall uptake in the reconstructed images if the hepatic-to-cardiac activity ratio (HCR) in 99mTc clinical myocardial SPECT studies is sufficiently high (> 1).

METHODS

To quantitatively relate hepatic uptake to this phenomenon, a commercial chest and heart phantom was modified with the addition of a customized liver insert, which was filled with various concentrations of 99mTc to simulate HCRs of 0:1, 1:1 and 2:1. The phantom was imaged with a high-sensitivity, three-detector camera, low-energy, high-resolution (LEHR) collimation and 180 degrees noncircular orbits.

RESULTS

Quantitative circumferential profile analysis of the reoriented SPECT images demonstrated artifactual inferior/inferoseptal maximal activity decreases of 17.8% and 46.2% for the 1:1 and 2:1 HCRs, compared to the 0:1 HCR. Hepatic scatter probably partly mitigates the decrease. Smoothing the projection data before reconstruction worsened the artifacts' severity. Using Butterworth filters of order 5 and cutoff frequencies of 0.1, 0.2 and 0.215 Nyquist (clinical standard) resulted in artifactual inferior wall activity decreases of 5%, 8% and 16%, compared to using the same filter with a cutoff of 0.3 for an HCR of 2:1.

CONCLUSION

These data indicate that if count statistics are good and liver uptake is high, higher frequency cutoffs in pre-reconstruction filters may improve specificity in 99mTc-labeled myocardial perfusion SPECT studies.

Posterior pituitary of the newborn marsupial possum, Trichosurus vulpecula

The fetal anterior pituitary-adrenal axis is thought to be involved in the initiation of birth in both eutherian and marsupial mammals. Little is known about the structure and function of the posterior pituitary at birth in the marsupial. Immunocytochemistry, high pressure liquid chromatography, and radioimmunoassay were used to identify vasopressin and mesotocin in the posterior pituitary of a newborn marsupial, the brushtail possum, Trichosurus vulpecula. The concentrations of vasopressin and mesotocin in the head of the newborn possum were 0.34 and 0.28 ng, respectively. The concentration of vasopressin was always greater than that of mesotocin, and the amounts of neuropeptides present in the head increased as the possum developed.

Technetium-99m teboroxime regional myocardial washout in subjects with and without coronary artery disease

The aim of this study was to test the hypothesis that regional myocardial washout of technetium-99m teboroxime is slowed in the presence of coronary stenosis. Washout was assessed in 33 catheterized patients and in 13 with a low likelihood of coronary artery disease, using a triple detector camera and dynamic single-photon emission computed tomography, with serial 1-minute acquisitions after injection of 20 to 25 mCi of teboroxime at the third minute of adenosine-induced hyperemia. Washout was measured as the percent change in counts between the first, second and third minutes after injection, as measured in 6 short-axis myocardial regions of interest. Myocardial regions were classified as ischemic (> or = 50% diameter stenosis and no prior myocardial infarct), infarcted, normal (no significant coronary stenosis) or "low likelihood" (from the 13 patients with a low likelihood of coronary artery disease). Teboroxime washout was significantly (p < 0.001) slowed in the ischemic myocardium (12.7 +/- 8.3%) compared with the normal (18.5 +/- 5.7%), low-likelihood (17.8 +/- 6.1%) and infarcted (17.8 +/- 4.4%) zones. There was regional variability in washout rates (% washout/min), with the anterior wall having the lowest (13.8 +/- 3.4%/min) and the inferior wall the highest (20.7 +/- 7.9%/min) values. In regard to individual coronary territories, 21 of 41 ischemic, noninfarcted territories (51%) had abnormal washout compared with 3 of 43 normal territories (7%) (p = 0.001). In conclusion, regional washout of teboroxime is detectably slowed in ischemic, noninfarcted myocardium. The clinical value of washout analysis in teboroxime single-photon emission computed tomography warrants further investigation.

Rapid back to back adenosine stress/rest technetium-99m teboroxime myocardial perfusion SPECT using a triple-detector camera

Technetium-99m-teboroxime is characterized by a high extraction fraction over a wide range of blood flow rates, rapid myocardial clearance and avid hepatic uptake. This study determined the imaging parameters and examined the clinical efficacy of a rapid back to back adenosine stress/rest teboroxime myocardial perfusion SPECT protocol using a triple-detector camera. Acquisition parameters were determined using cardiac phantom studies which were then applied in SPECT studies of 51 catheterized patients (22 with prior myocardial infarction) and 20 patients with a "low" (7.9% +/- 4.3%) likelihood of coronary artery disease. Technetium-99m-teboroxime (20-25 mCi) was injected at the third minute of adenosine infusion. Teboroxime (20-25 mCi) was also injected at rest, 15 min later. Stress followed by rest SPECT were completed within 25 min using a triple-detector camera and sequential, 1-min continuous rotations in alternating directions. Summed raw data from the first to second (1-2 min), second to third (2-3 min) and second to fifth (2-5 min) minutes of imaging following stress teboroxime injection were reconstructed and compared for image quality, degree of liver interference, and accuracy for diagnostic efficacy. In a subgroup of 30 patients, 2-8-min summed images were also reconstructed to compare this more conventional imaging protocol with our rapid acquisition. Image quality was fair to good in 75% of the 1-2-min, 84% of the 2-3-min and 2-5-min studies and 53% of the 2-8-min scans. The frequency of severe liver interference appeared to increase with the duration of imaging time (1-2 min: 3%; 2-3 min: 7%; 2-5 min: 8%) and was greatest (30%, p = 0.08) with 2-8-min images. Three patients (4%) had uninterpretable studies due to intense hepatic uptake. Overall sensitivity (95%) and specificity (71%) were equal for the 2-3-min and 2-5-min stress images and appeared better than in the 1-2-min images (84% and 57%, respectively). For the 2-8-min scans, vessel sensitivity (69%) and specificity (63%) appeared poorer than with 2-3-min studies (83% and 81%, respectively). Normalcy rates were 89% for the 2-3-min and 2-5-min and 79% for 1-2-min images. The back to back adenosine stress/rest teboroxime SPECT can be performed in 30 min using a triple-detector camera. Although overall high sensitivity and normalcy rates were achieved, the protocol is technically demanding. Interference due to intense liver uptake remains problematic.

Detection and correction of patient motion in dynamic and static myocardial SPECT using a multi-detector camera

We have developed a method for the detection and correction of translational patient motion in dynamic and static myocardial SPECT studies. The method uses a low activity 99mTc point source and is especially designed for multi-detector cameras. The source's centroid coordinates are measured or derived for all projection images in a temporal frame. The coordinate curves fitted to predicted distributions and the projection images shifted to realign measured to fitted values, with sub-pixel accuracy. In dynamic studies, the frame with the best fits serves as reference for all others. The accuracy of this method, measured with cardiac phantom experiments, was found to be +/- 0.37 mm and +/- 0.44 mm in the axial and transaxial dimension, respectively. By comparison, overall motion in 42 patients undergoing 99mTc-teboroxime dynamic cardiac SPECT studies was +/- 1.6 mm and +/- 1.2 mm, respectively (average on 39,272 projection views). Application of the method to phantom experiments, 99mTc-sestamibi and 99mTc-teboroxime human studies visually eliminated artifactual perfusion defects from simulated phantom motion and actual patient motion.

Radiation therapy in clinical stage I and II Hodgkin's disease. The Princess Margaret Hospital Lymphoma Group

A review of the Princess Margaret Hospital experience over the last 20 years in treating clinically staged patients with stage I and II Hodgkin's disease was performed to analyse the impact of patient selection and extended field radiation on relapse and survival. Of the 878 patients with stage I and II Hodgkin's disease, 521 with clinical stages I and II received radiation alone as the initial treatment. The actuarial survival for all stage I and II patients was 85.1% at 5 years and 76.2% at 10 years, and for clinically staged patients treated with radiation alone, 87.2 and 77.6%, respectively. The relapse-free rate (RFR) for all clinical stage I and II patients treated with radiotherapy (RT) alone was 70.1% at 5 years and 65.8% at 10 years. Significant prognostic factors for RFR and survival included age, stage and histology. In addition, the extent of radiation was identified as an independent prognostic factor for survival as well as for relapse. The RFR for those treated with involved field RT was 58.4% at 5 years and 50.5% at 10 years; for patients treated with mantle RT, 69.9 and 65.6%, and those treated with extended field RT 77.4 and 75.8%, respectively. In a highly selected group of patients with no adverse features, i.e. with stages IA-IIA, lymphocyte predominant or nodular sclerosis histology, erythrocyte sedimentation rate < 40, age < 50, no large mediastinal mass, and no E-lesions--the policy of mantle RT (M) and extended field RT (EF) produced comparable 5-year relapse-free rates (M, 84.9%; EF, 87.1%; P = 0.53). We conclude that a policy of treatment selection based upon clinicopathological prognostic factors and the use of extended field RT confers excellent results in the treatment of clinical stage I and II Hodgkin's disease.

Analysis of supradiaphragmatic clinical stage I and II Hodgkin's disease treated with radiation alone

Patients with clinical Stage I and II Hodgkin's disease have been managed at the Princess Margaret Hospital for over 20 years, without the use of routine staging laparotomy. Our experience identified as adverse prognostic factors presence of a large mediastinal mass, B symptoms, and advanced age in presence of unfavorable histology (20). We had suggested previously that the use of extended field radiation therapy (XRT) was associated with a lower risk of relapse than involved field XRT or mantle XRT. There has been a trend over the past decade to select those patients with favorable prognostic factors for treatment with XRT alone and to use mantle plus upper abdominal XRT (extended field XRT) to treat them. A retrospective study of patients with clinical Stage I and II Hodgkin's disease treated at the Princess Margaret Hospital between 1978 and 1986 was conducted to determine the impact of patient selection and extended field radiation on outcome. The study involved 250 patients with supradiaphragmatic disease selected for treatment with radiation alone on the absence of adverse prognostic factors. Radiation techniques included involved field radiation in selected patients (those with upper neck involvement), mantle radiation in the earlier years, and mantle plus upper abdominal radiation in the later years of the study. Actuarial survival was 83.3% at 8 years; cause-specific survival was 90.1% and the relapse-free rate 71.6%. Local tumor control was 94.6%; only two patients had true infield failure. Multivariate analysis showed that significant prognostic factors included age, histology, and erythrocyte sedimentation rate. Extent of the radiation treatment volume was significant and influenced the risk of relapse, particularly out-of-field relapse, independently of other factors. A dose of 35 Gy was found to be sufficient for control of clinical disease. This study validated a previously developed model for the selection of clinically staged patients with Stage I and II Hodgkin's disease for treatment with radiation alone. Careful selection of these patients can yield excellent results without requiring that staging laparotomy be routinely performed or the use of systemic chemotherapy as the initial treatment.

Bladder cancer: long-term follow-up results of patients treated with radical radiation

Carcinoma of the bladder is commonly treated for cure with external beam radiation. Whilst short-term results are associated with a good chance of disease control there is little information about the long-term results of such therapy. We present a retrospective review of the Princess Margaret Hospital experience in treating transitional cell carcinoma of the bladder and emphasis on the long-term follow-up of patients treated with radiotherapy (XRT). Between 1972 and 1980, 355 patients were treated with a radical course of external beam radiation. The overall survival was 20% at 10 years and the cause-specific survival was 32%. Radiation treatment resulted in a long-term bladder preservation in at least 25% of patients. The majority of long-term survivors without evidence of relapse were patients with T1 (solitary tumours), T2 and T3a tumours. This subgroup represents patients with disease favourable for treatment with radiation. Factors affecting response to the XRT and survival included T stage and tumour bulk. Radiation complications were frequent and were usually associated with local disease recurrence.

Outcome analysis of localized gastrointestinal lymphoma treated with surgery and postoperative irradiation

One hundred thirteen patients with localized gastrointestinal lymphoma treated by surgery and postoperative irradiation between 1967 and 1985 were reviewed. At 15 years, actuarial survival of this group was 40.6%, with a cause-specific survival of 69.2% and a relapse-free rate of 64%. Two-thirds of relapses occurred at distant sites. In Stage IA and IIA patients with no residuum or with positive resection margins, (N = 90) only site of involvement and stage predicted for relapse. Age, histologic subtype group, and depth of bowel wall invasion did not affect relapse risk. In the very favorable group (Stage IA, IIA, no residuum or microscopic residuum), 8.4% of patients with stomach lymphoma relapsed compared to 25% of patients with small bowel lymphoma. The risk of early relapse was higher in those with Stage IIA small bowel lymphoma than those with Stage IA small bowel lymphoma. We continue to recommend adjuvant abdominal irradiation for patients with Stage IA, IIA completely resected stomach lymphoma and Stage IA completely resected small bowel lymphoma. We recommend combined modality therapy for patients with completely resected Stage IIA small bowel lymphoma and all other localized gastrointestinal lymphoma where visible residual disease is present.

Radical radiotherapy for muscle invasive transitional cell carcinoma of the bladder: failure analysis

Patients with muscle invasive carcinoma of the bladder treated with radical radiation were prospectively documented and followed in an attempt to identify prognostic factors predictive of the response to treatment. Data on 121 consecutive patients treated with radical radiation between 1981 and 1985 are presented. Over-all actuarial survival of the patient population (median age 70 years) was 31.6% at 5 years and cause-specific survival was 44.8%. At analysis 33 of 121 patients (27.3%) were alive with preserved bladder function. Independent prognostic factors for cause-specific survival and for complete response with radical radiation were tumor configuration, hemoglobin level and clinical stage. The rate free of local relapse was significantly influenced by stage and presence of coexistent carcinoma in situ. The study suggests that factors other than stage and grade influence prognosis in invasive bladder cancer and should be considered in interpreting treatment results.

Breast cancer and pregnancy: the ultimate challenge

An update on a series of 413 patients with carcinoma of the breast associated with pregnancy and referred to The Princess Margaret Hospital between 1931 and 1985 is presented. Coincident pregnancy is seriously detrimental to survival and, to a lesser degree, lactation. Subsequent pregnancies do not affect survival provided the pregnancy occurs at least one year after treatment for breast cancer, and preferably two years. Subsequent pregnancy may confer an improved prognosis. Interference in terms of a therapeutic abortion in breast cancer with coincident, lactational and subsequent pregnancies, is associated with decreased survival and ovarian ablation confers no benefit. Investigation and local treatment for coincident pregnancies should be limited to the absolute minimum necessary to achieve local control. Aggressive management should be reserved for acute life-threatening situations and then only after frank discussion with the patient. Adjuvant therapy is recommended after delivery and for lactational presentations, even if nodes are negative, due to the poor prognosis.

The role of surgery in the management of thyroid lymphoma

The role of surgery in the management of patients with primary lymphoma of the thyroid gland has been addressed after review of 61 patients treated at Princess Margaret Hospital between 1958 and August 1982, 46 of whom had clinical stage I and II disease confined to the thyroid gland or lymph nodes or both above the diaphragm. Postoperative radiation therapy was used in 34 patients, radiation therapy and chemotherapy in 11 patients, and chemotherapy alone in 1 patient. Analysis of disease progression, local relapse, and distant disease recurrence indicated that postoperative residual disease bulk predicted strongly for both local and distant disease progression. Overall cause-specific survival was 59% at 5 years, with a relapse-free rate of 46% at 5 years. Of those with less than 2.5 cm of residual disease after surgery, 80% achieved lifelong local disease control compared with 40% for those with residual disease in excess of 2.5 cm after surgery. Distant relapse rates were 7% and 23% for those with less than 2.5 cm and greater than 2.5 cm after surgery, respectively. The long-term survival rate for those with disease progression during this period was approximately 10%, with a median survival expectancy of 18 months. It is suggested that those patients without an antecedent cytologically based diagnosis of lymphoma undergo biopsy and removal of operable tumor without compromise of parathyroid glands, recurrent laryngeal nerves, or appearance. Those patients with an existing cytologic diagnosis of lymphoma and bulky and/or inoperable tumor may be more effectively managed with a combined chemotherapy-radiation therapy program.

Patterns of disease in localized extranodal lymphomas

The site of origin of lymphoid tissue is an important determinant of lymphocyte migration patterns. The association of gastrointestinal (GI) and Waldeyer's ring lymphoma and the unique lymphocyte migration pattern of gut-associated lymphoid tissue (GALT) have been previously described. To establish whether predictive clinical patterns of disease occur in localized Non-Hodgkin's lymphoma, survival and relapse patterns for 496 patients with stage I and II non-Hodgkin's lymphoma (NHL) treated with loco-regional irradiation (XRT) alone were examined. We identified 139 patients with GALT lymphoma (defined as arising from primitive gut and including Waldeyers' ring, thyroid, and GI lymphomas) and 87 patients with extranodal non-gut-associated lymphoma (ENL). Survival and relapse data were assessed in multifactorial analysis to correct for previously identified other prognostic variables. GALT lymphomas (GALT-L) have a survival advantage compared with other ENL (P = .017) independent of stage and histology. A difference in distant relapse (DR) rate between GALT-L and other ENL (P = .0002) was also identified. The presentation site of localized extranodal NHL is predictive of clinical behavior and is an independent determinant of outcome. This may be an expression of lymphocytic origin and determinants of migration patterns.

Role of radiation therapy in localized non-Hodgkin's lymphoma

Relapse occurs in 50% of patients receiving radiation for clinical stage (C.S.) I and II nodal and extranodal non-Hodgkin's lymphoma (N.H.L.). Prior to the introduction of intensive chemotherapy those failing primary control with irradiation and most of those who relapsed died of their disease with a resultant overall mortality of 50%. An analysis of Princess Margaret Hospital results with radiation for C.S. I and II N.H.L. between January 1967 and December 1978 revealed that tumour bulk, age, stage and histology were of independent prognostic significance. It was possible to group patients using combinations of these attributes so that each group encompassed only patients with similar outcomes. Such prognostic groups were identified separately within the low grade and the intermediate plus high grade categories of the Working Formulation. Patients with a high probability of cure with radiation were so defined. Also those patients in whom chemotherapy would be optimal initial therapy were also defined. Such patients were in the intermediate plus high grade histology groups. Thirty percent of all patients with low grade histology lymphoma had an actuarial survival of 83%, and relapse-free rate of 63% at 10 years. By implication, approximately 20% of all patients with these histologies seen at the Princess Margaret Hospital for the same time period achieved prolonged relapse-free survival by localized therapy. This is at variance with the implications of staging from studies where laparotomy and multiple bone marrow biopsies have been used. Such aggressive staging procedures suggest truly localised disease in only 5-6% of patients with low grade lymphoma. A significant relationship between radiation dose and disease control was demonstrated only for patients with intermediate and high grade lymphoma of medium or large bulk. A minimum tumour dose of 30 Gy was required for optimal local control with radiation.

Prognostic groups for management of localized Hodgkin's disease

Two hundred fifty-two patients receiving radical irradiation for clinical stages I and II Hodgkin's disease between 1968 to 1977 had an actuarial ten-year survival rate of 78% and a relapse-free rate of 61%. Sixty-seven patients receiving chemotherapy followed by radiation had a 78% survival rate and a 63% relapse-free rate. Independent prognostic factors for survival and relapse were age, stage, and histology. Disease bulk was predictive only of relapse. Neither site of presentation above or below the diaphragm nor presence of mediastinal involvement was predictive for survival or relapse; however, patients with large mediastinal masses (greater than or equal to 10 cm absolute diameter) had a significantly higher intrathoracic failure rate with conventional mantle irradiation. Analysis of failure, according to age, clinical stage, and histologic type, showed three groups of patients defined according to the risk of relapse with radiation therapy: those with isolated upper cervical stage IA disease (group 1, relapse rate 8%), younger patients with localized stages I and II disease of favorable histologic type (group 2, relapse rate 35%), and older patients with extensive or symptomatic stages I and II disease of less favorable histologic type (group 3, relapse rate 70%). Subsequent analysis of radiation treatment volume indicates that the use of upper abdominal irradiation for patients in group No. 2 could yield results equivalent to those achieved with radiation therapy for surgically staged patients.