Work-specific cognitive symptoms and the role of work characteristics, fatigue, and depressive symptoms in cancer patients during 18 months post return to work.

OBJECTIVE: Cancer patients can experience work-specific cognitive symptoms post return to work. The study aims to (1) describe the course of work-specific cognitive symptoms in the first 18 months post return to work and (2) examine the associations of work characteristics, fatigue and depressive symptoms with work-specific cognitive symptoms over time. METHODS: This study used data from the 18-month longitudinal "Work Life after Cancer" cohort. The Cognitive Symptom Checklist-Work Dutch Version (CSC-W DV) was used to measure work-specific cognitive symptoms. Linear mixed models were performed to examine the course of work-specific cognitive symptoms during 18-month follow-up; linear regression analyses with generalized estimating equations were used to examine associations over time. RESULTS: Working cancer patients examined with different cancer types were included (n = 378). Work-specific cognitive symptoms were stable over 18 months. At baseline, cancer patients reported more working memory symptoms (M = 32.0; CI, 30.0-34.0) compared with executive function symptoms (M = 19.3; CI, 17.6-20.9). Cancer patients holding a job with both manual and nonmanual tasks reported less work-specific cognitive symptoms (unstandardized regression coefficient b = -4.80; CI, -7.76 to -1.83) over time, compared with cancer patients with a nonmanual job. Over time, higher depressive symptoms were related to experiencing more overall work-specific cognitive symptoms (b = 1.27; CI, 1.00-1.55) and a higher fatigue score was related to more working memory symptoms (b = 0.13; CI, 0.04-0.23). CONCLUSIONS: Job type should be considered when looking at work-specific cognitive symptoms over time in working cancer patients. To reduce work-specific cognitive symptoms, interventions targeted at fatigue and depressive symptoms might be promising.

Utility of the stroke-thrombolytic predictive instrument.

OBJECTIVE: The goal of this study was to evaluate the utility of the stroke thrombolytic predictive instrument (s-TPI) in predicting clinical outcome in patients with acute ischaemic stroke treated with intravenous tissue plasminogen activator (t-PA). METHODS: The study assessed the external validity of the s-TPI in 301 consecutive stroke patients treated with intravenous t-PA. Clinical outcome was measured with the modified Rankin scale (mRs) at 3 months. The study used the s-TPI to calculate probabilities of a good outcome (mRs 0-1) and a poor outcome (mRs 5-6). We compared these probabilities with the observed outcome using receiver-operator characteristics (ROC) curves and calibration curves. Subgroup analyses for different onset-to-treatment time windows were performed. RESULTS: According to the s-TPI, the mean predicted probability of a good and a poor outcome in the validation cohort were 0.45 and 0.17. The area under the ROC curves were 0.80 (4.5-hour time window), 0.82 (3-hour time window) and 0.77 (3-4.5 hours time window) for predicting good outcome, and 0.78 (4.5 hours), 0.80 (3 hours) and 0.74 (3-4.5 hours) for predicting poor outcome. Calibration curves revealed a slight overestimation of probabilities of a good outcome and underestimation of probabilities of a poor outcome. CONCLUSIONS: The s-TPI appears to be reasonably valid for predicting outcome after t-PA treatment in daily practice, although a slight overestimation of a good and underestimation of a poor outcome was observed.

Validation of a method to measure the proprioception of the knee.

INTRODUCTION: Proprioception is an important mechanism in knee stability and function. After an injury like an anterior cruciate ligament (ACL) rupture changes appear in knee proprioception which play a major role in rehabilitation. There are several methods to measure proprioception; the threshold to detect passive motion (TTDPM) is often used to quantify proprioception. In this study the reliability and validity were tested of an apparatus, which measures the TTDPM based on the Lund technique of Fridén and Roberts (Sweden). MATERIALS AND METHODS: Sixteen healthy participants were tested on both legs, from start position 20 degrees and 40 degrees, towards extension (TE) and flexion (TF). The same measurement was repeated 12 (6-21) days later. RESULTS: An overall mean TTDPM of 0.58 degrees (95% confidence interval CI=0.53-0.62 degrees ) was found. Thresholds were different depending on direction of motion and start position. TTDPM in 20 degrees TE (0.51 degrees, CI=0.48-0.56 degrees) and in 40 degrees TF (0.54 degrees, CI=0.50-0.58 degrees ) were significantly lower than TTDPM in 40 degrees TE (0.68 degrees , CI=0.63-0.74 degrees) and in 20 degrees TF (0.58 degrees, CI=0.54-0.63 degrees). Thresholds were rising with age. Women had higher thresholds than men. CONCLUSION: The method is a reliable and valid way to measure proprioception. The next step is to use this method on patients with an ACL-rupture and compare these results with healthy subjects.

Solid-state framing camera operating in interferometric mode.

A high speed solid-state framing camera has been developed which can operate in interferometric mode. This camera measures the change in the index of refraction of a semiconductor when x-rays are incident upon it. This instrument uses an x-ray transmission grating/mask in front of the semiconductor to induce a corresponding phase grating in the semiconductor which can then be measured by an infrared probe beam. The probe beam scatters off of this grating, enabling a measure of the x-ray signal incident on the semiconductor. In this particular instrument, the zero-order reflected probe beam is attenuated and interfered with the diffracted orders to produce an interferometric image on a charge coupled device camera of the phase change induced inside the semiconductor by the incident x-rays.

Fatigue and depressive symptoms improve but remain negatively related to work functioning over 18 months after return to work in cancer patients.

PURPOSE: The aims of this study are to investigate the course of work functioning, health status, and work-related factors among cancer patients during 18 months after return to work (RTW) and to examine the associations between these variables and work functioning over time. METHODS: Data were used from the 18-month longitudinal "Work Life after Cancer" (WOLICA) cohort, among 384 cancer patients who resumed work. Linear mixed models were performed to examine the different courses during 18-month follow-up. Linear regression analyses with generalized estimating equations (GEE) were used to examine the associations and interactions. RESULTS: Cancer patients reported an increase of work functioning and a decrease of fatigue and depressive symptoms in the first 12 months, followed by a stable course between 12 and 18 months. Cognitive symptoms were stable during the first 18 months. Working hours increased and social support decreased during the first 6 months; both remained stable between 6 and 18 months. Fatigue, depressive, and cognitive symptoms were negatively associated with work functioning over time; working hours and supervisor social support were positively associated. CONCLUSIONS: Interventions to improve cancer patients' work functioning over time might be promising if they are aimed at reducing fatigue, depressive symptoms, cognitive symptoms, and encouraging supervisor social support. IMPLICATIONS FOR CANCER SURVIVORS: It is important to monitor cancer patients not only in the period directly after RTW but up to 18 months after RTW, allowing for timely interventions when needed.

Measuring disability in stroke: relationship between the modified Rankin scale and the Barthel index.

BACKGROUND AND PURPOSE: The effectiveness of therapeutic interventions in acute stroke trials is traditionally measured with the modified Rankin scale (mRs) and the Barthel index (BI). The mRs is a global disability scale divided into six steps from total independence to total dependence. The BI assesses ten basal activities of daily living, of which eight assess level of dependence (bathing, grooming, using stairs, dressing, feeding, toilet use, transfers and walking). The aim of this study was to investigate the relationship between the mRs and the total scores and item-scores of the BI. METHODS: During a period of 3 months mRs and BI scores were collected from two multicentre randomised, placebo-controlled trials with lubeluzole (515 and 519 patients). In each patient we compared the mRs grades with the total BI score and the scores on the ten subitems. RESULTS: For both trials there was extensive overlap of BI scores between mRs grades and a wide range in BI scores among patients with mRs grades 3 and 4. We also found discrepancies between the BI item-scores and mRs grades. About 40% of patients with mRs grades 1 (able to carry out all usual activities) and 2 (able to look after own affairs without assistance) were not independent on at least one activity of the BI. In both studies, about 30% of the patients needed help or supervision for walking, although they were classified as mRs 3 (requiring some help but able to walk without assistance). CONCLUSIONS: Investigators in stroke trials use the mRs as a subjective global disability scale, and they do not strictly take into account limitations in performing specific basal activities of daily living, as assessed by the BI, to assign mRs grades.

Safety of routine IV thrombolysis between 3 and 4.5 h after ischemic stroke.

BACKGROUND: The administration of tissue plasminogen activator (t-PA) has been proven effective for ischemic stroke within 3 h after onset. A pooled-analysis of six trials showed that intravenous t-PA still improves outcome when given between 3 to 4.5 h after stroke onset. On the basis of this pooled analysis, t-PA was also routinely offered to our patients between 3-4.5 h. We report the safety and clinical features of this group together with the features of the group given t-PA within 3 h. METHODS: Prospectively patient characteristics, stroke severity, stroke subtype, incidence of symptomatic intracerebral hemorrhage (SICH), in-hospital mortality, and 3-months modified Rankin Scale scores (mRS) were registered. Data was analyzed separately for patients treated within 3 h (early group) and those treated between 3-4.5 h (late group). RESULTS: Among 176 patients who underwent intravenous thrombolysis, 101 were treated in the early group and 75 in the late group. Six (5.9%; 95% CI 2.8%-12.3%) patients in the early group and 4 (5.3%; 95% CI 2.2%-12.9%) in the late group developed SICH (p=1.0). In the early group 13 (12.9%; 95% CI 7.7%-20.8%) patients died within 7 days after admission, compared to 5 (6.7%; 95% CI 3.0%-14.7%) in the late group (p=0.179). In the early group 44 (43.6%; 95% CI 43.3%-53.3%) were independent (mRS< or =2) at three months, compared to 36 (48.0%; 95% CI 37.0%-59.1%) in the late group (p=0.559). CONCLUSION: Our data show no trend of decreased safety of thrombolysis beyond 3 h. Due to a small sample size a harmful effect cannot be excluded but seems unlikely.

Two mouse retinal degenerations caused by missense mutations in the beta-subunit of rod cGMP phosphodiesterase gene.

We report the chromosomal localization, mutant gene identification, ophthalmic appearance, histology, and functional analysis of two new hereditary mouse models of retinal degeneration not having the Pde6brd1("r", "rd", or "rodless") mutation. One strain harbors an autosomal recessive mutation that maps to mouse chromosome 5. Sequence analysis showed that the retinal degeneration is caused by a missense point mutation in exon 13 of the beta-subunit of the rod cGMP phosphodiesterase (beta-PDE) gene (Pde6b). The gene symbol for this strain was set as Pde6brd10, abbreviated rd10 hereafter. Mice homozygous for the rd10 mutation showed histological changes at postnatal day 16 (P16) of age and sclerotic retinal vessels at four weeks of age, consistent with retinal degeneration. Retinal sections were highly positive for TUNEL and activated caspase-3 immunoreactivity, specifically in the outer nuclear layer (ONL). ERGs were never normal, but rod and cone ERG a- and b-waves were easily measured at P18 and steadily declined over 90% by two months of age. Protein extracts from rd10 retinas were positive for beta-PDE immunoreactivity starting at about the same time as wild-type (P10), though signal averaged less than 40% of wild-type. Interestingly, rearing rd10 mice in total darkness delayed degeneration for at least a week, after which morphological and functional loss progressed irregularly. With the second strain, a complementation test with rd1 mice revealed that the retinal degeneration phenotype observed represents a possible new allele of Pde6b. Sequencing demonstrated a missense point mutation in exon 16 of the beta-subunit of rod phosphodiesterase gene, different from the point mutations in rd1 and rd10. The gene symbol for this strain was set as Pde6bnmf137, abbreviated nmf137 hereafter. Mice homozygous for this mutation showed retinal degeneration with a mottled retina and white retinal vessels at three weeks of age. The exon 13 missense mutation (rd10) is the first known occurrence of a second mutant allele spontaneously arising in the Pde6b gene in mice and may provide a model for studying the pathogenesis of autosomal recessive retinitis pigmentosa (arRP) in humans. It may also provide a better model for experimental pharmaceutical-based therapy for RP because of its later onset and milder retinal degeneration than rd1 and nmf137.

Digital correction of magnification in pelvic x rays for preoperative planning of hip joint replacements: theoretical development and clinical results of a new protocol.

The introduction of digital radiological facilities leads to the necessity of digital preoperative planning, which is an essential part of joint replacement surgery. To avoid errors in the preparation and execution of hip surgery, reliable correction of the magnification of the projected hip is a prerequisite. So far, no validated method exists to accomplish this. We present validated geometrical models of the x-ray projection of spheres, relevant for the calibration procedure to correct for the radiographic magnification. With help of these models a new calibration protocol was developed. The validity and precision of this procedure was determined in clinical practice. Magnification factors could be predicted with a maximal margin of error of 1.5%. The new calibration protocol is valid and reliable. The clinical tests revealed that correction of magnification has a 95% margin of error of -3% to +3%. Future research might clarify if a strict calibration protocol, as presented in this study, results in more accurate preoperative planning of hip joint replacements.

Concentrations of mercury in tissues of beluga whales (Delphinapterus leucas) from several communities in the Canadian Arctic from 1981 to 2002.

Beluga whales have been hunted for food by Native People in the Canadian Arctic since prehistoric time. Here we report the results of analyses of total mercury in samples of liver, kidney, muscle and muktuk from collections over the period 1981-2002. We compare these results with human consumption guidelines and examine temporal and geographic variation. Liver has been analyzed more frequently than other organs and it has been used as the indicator organ. Mercury accumulates in the liver of the whales over time so that the whale ages are usually linked statistically to their levels of mercury in liver. Virtually all the samples of 566 animals analyzed contained mercury in liver at concentrations higher than the Canadian consumption guideline of 0.5 microg g-1 (wet weight) for fish. (There is no regulatory guideline for concentrations in marine mammals in Canada.) Samples from locations in the Mackenzie Delta in the western Canadian Arctic and from Pangnirtung in the eastern Canadian Arctic were obtained more often than from other location and these offered the best chances to determine whether levels have changed over time. Statistical outlier points were removed and the regressions of (ln) mercury in liver on age were used to calculate the level of mercury in whales of age 13.1 years in order to compare age-adjusted levels at different locations. These age-adjusted levels and also the slopes of regressions suggested that levels have increased in the Mackenzie Delta over the sampling period although not in a simple linear fashion. Other locations had fewer collections, generally spread over fewer years. Some of them indicated differences between sampling times but we could not establish whether these differences were simply temporal variation or whether they were segments of a consistent trend. For example, the levels in whales from Arviat were considerably higher in 1999 than in 1984 but we have only two samples. Similarly, samples from Iqaluit in 1994 exceeded considerably those in 1993 and the interval seems too short to reflect any regional temporal trend and more likely represent an extreme case of year-to-year variation. Previous analyses of data from geographically distinct groups had suggested that whales in the western Canadian Arctic had higher levels of mercury than those from the eastern Canadian Arctic. The present analysis suggests that such regional differences have diminished and are no longer statistically significant. No site has indicated significant decreases in more recent samples. The levels of total mercury in the most analyzed organs fell in the order of liver (highest levels), kidney, muscle and muktuk (lowest level). While muktuk had the lowest level of the organs most frequently analyzed, it is the preferred food item from these whales and it still exceeded the consumption guideline in most instances.

Comparing self-report, clinical examination and functional testing in the assessment of work-related limitations in patients with chronic low back pain.

PURPOSE: To compare the work-related limitations assessed using self-report, clinical examination and functional testing in patients with chronic low back pain (CLBP). METHODS: Work-related limitations of 92 patients were assessed using self-report, clinical examination and functional testing. To obtain the assessed limitations the patient (self-report), the physician (clinical examination) and a trained evaluator (functional testing) completed a scorings form about the work-related limitations of the patient. The Isernhagen Work Systems Functional Capacity Evaluation (IWS FCE) was used to obtain the functional testing results. A kappa value of more than 0.60, absolute agreement of more than 80% and ICC of more than 0.75 were considered as acceptable. RESULTS: Little agreement and correlation among self-report, clinical examination and functional testing were found for the assessment of work-related limitations. Self-reported limitations were considerably higher than from those derived from clinical examination or functional testing. Additionally, the limitations derived from the clinical examination were higher than those derived from the IWS FCE. CONCLUSION: Comparing self-report, clinical examination and functional testing for assessing work-related limitations in CLBP patients showed large considerable differences in limitations. Professional health care workers should be aware of these differences when using them in daily practice.

[Reduction in the consumption of benzodiazepines due to a letter to chronic users from their own general practitioner]. / Vermindering van gebruik van benzodiazepinen door een brief van de eigen huisarts aan chronische gebruikers.

OBJECTIVE: To investigate the effectiveness of a minimal intervention in reducing the volume of prescription of benzodiazepines at the regional level. DESIGN: Prospective. METHOD: Patients on compulsory health insurance who had received 180 or more daily doses of benzodiazepines in the course of one year received a letter from their general practitioner (GP) with information about the risks of chronic use, the advice to reduce or stop use, and an invitation to make an appointment to discuss the problem. This intervention took place in 19 GP practices in East Groningen. A reminder was sent six months later to the patients who had not responded in 9 randomly selected GP-practices. Thirty-seven practices in East Groningen and 91 practices in Northwest Groningen served as controls. Outcome measures were: (a) the percentage of patients who stopped, and (b) the change in average benzodiazepine consumption. RESULTS: During the period 6-12 months after the first letter in the intervention group (n = 1343), 11.3% of the patients (95% CI: 9.6-13.1) received no prescription whatsoever for benzodiazepines compared to 5.4% (4.6-6.3) and 4.9% (4.2-5.5) in East Groningen (n = 2932) and in Northwest Groningen (n = 4562), respectively. The average decrease in prescription volume was 13% (-9.9 to -15.1) in the intervention group compared to 3% (-0.1 to -4.1) and 3% (-1.5 to -4) in the control groups. The reminder sent half a year later had no additional effect. CONCLUSION: The informative letter from the GP to chronic users of benzodiazepines with the advice to stop or reduce this use was effective.

ANF receptors: distribution and regulation in central and peripheral tissues.

Atrial natriuretic factor is a recently-discovered family of biologically active peptides produced in, stored and secreted by mammalian atria. ANF exerts a wide variety of actions in the periphery as well as within the central nervous system. In general, these actions are directed toward the maintenance of body fluid and electrolyte balance and regulation of arterial blood pressure. In a fashion similar to that of many other hormonal systems, the actions of ANF in various target tissues appear to be mediated by at least one class of specific receptors. However, while the biosynthesis and biological actions of ANF have been extensively investigated, little research has been focused on ANF receptor systems. In this article, we will provide an overview of current literature regarding the distribution and binding characteristics of receptor sites for ANF in peripheral and central target tissues. In addition, we will consider factors involved in the regulation and alteration of ANF receptor sites in various tissues. Finally, a brief discussion of the emerging concept of ANF and angiotensin II as mutual antagonists in body fluid homeostasis and cardiovascular regulation will be offered.

Levels of insulin-like growth factor (IGF) binding proteins, luteinizing hormone and IGF-I receptors, and steroids in dominant follicles during the first follicular wave in cattle exhibiting regular estrous cycles.

Objectives of this study were to determine if concentrations of steroids, insulin-like growth factor -I (IGF-I), and IGF binding proteins (IGFBP) in follicular fluid and numbers of LH and IGF-I receptors change during growth of the dominant follicle. Ovarian follicular development was monitored daily via ultrasound in lactating Holstein cows. Animals underwent bilateral ovariectomy when the dominant follicle was first identified (days 4-6; estrus = day 0; early; n = 5) or when it stopped growing (days 8-12; late; n = 8). All follicles were classified as dominant (DF), large (LG; > = 6 mm in diameter, excluding DF) or small (SM; < 6 mm), follicular fluid was aspirated, and theca and granulosa cells were collected. Levels of IGFBP-2, assessed via ligand blotting, were greater (P < 0.05) in LG and SM follicles compared with DF in early cows. Levels of IGFBP-3 in follicular fluid were unaffected by follicle class. Numbers of specific 125I-hCG/LH binding sites in thecal cells were greater (P < 0.01) in DF compared with LG and SM follicles of both early and late cows. Numbers of specific 125I-hCG/LH binding sites in granulosa cells were similar for follicle sizes in early cows, but, in late cows, were greater (P < 0.01) in DF compared with SM follicles and were severalfold greater (P < 0.01) in late DF compared with early DF. Numbers of receptors for IGF-I in thecal cells were 2-fold greater (P < 0.05) in DP and LG compared with SM in late cows. Numbers of IGF-I receptors in granulosa cells were unaffected by size or growth of follicles, but were severalfold greater than in theca cells. Concentrations of estradiol were severalfold greater (P < 0.01) in DF compared with LG and SM in both early and late cows. Concentrations of androstenedione in early cows were greater (P < 0.05) in DF and SM compared with LG follicles. Concentrations of progesterone and IGF-I did not differ (P > 0.10) among follicle classes, but both were greater (P < 0.10) in late LG compared with early LG follicles. Concentrations of IGF-II in follicular fluid did not differ (P > 0.10) between early and late cows but were greater (P < 0.10) in SM than DF or LG follicles. We conclude that low amounts of IGFBP-2 and increased thecal binding sites for hCG/LH appear to be related to establishment of the dominant follicle during the first follicular wave in cattle exhibiting regular estrous cycles during late lactation.

Alterations in binding sites for atrial natriuretic factor in kidneys and adrenal glands of Dahl hypertension-sensitive rats.

Binding sites for atrial natriuretic factor (ANF) were studied in kidneys and adrenal glands of 7- and 10-week-old male Dahl hypertension-sensitive (S/JR) and hypertension-resistant (R/JR) rats by quantitative autoradiography. Binding sites for 125I-ANF-28 in kidney were highly localized and of high density in the glomeruli; binding sites were less concentrated in the renal papilla. In adrenal gland, binding sites for 125I-ANF-28 were highly concentrated in the zona glomerulosa, but were of a very low density in the inner adrenal cortex. At 7 weeks of age, the maximum binding capacity (Bmax) for 125I-ANF-28 in kidney glomeruli was increased by 21% in S/JR rats compared with R/JR rats. From 7 to 10 weeks of age, decreases in Bmax for 125I-ANF-28 in glomeruli occurred, with no apparent difference between strains. Strain or age differences in the affinity constant (Ka) for 125I-ANF did not occur in the kidney. In adrenal zona glomerulosa, the Bmax for 125I-ANF-28 binding was similar for S/JR and R/JR rats at 7 weeks of age. At 10 weeks of age, however, Bmax for 125I-ANF-28 in adrenal zona glomerulosa was increased by 19% in S/JR rats compared with age-matched R/JR controls. These findings suggest that alterations may occur in ANF binding sites in kidney and adrenal gland of S/JR rats in response to the sharp increase in blood pressure that is characteristic of rats of this strain.

Demonstration of differential post-stenotic myocardial technetium-99m-teboroxime clearance kinetics after experimental ischemia and hyperemic stress.

The clearance kinetics of the perfusion tracer 99mTc-teboroxime were evaluated in post-stenotic and normal myocardium using dynamic planar gamma camera imaging in pre-instrumented dogs in the control state (n = 9) and following total occlusion (2 min), pharmacologic stress with adenosine [80 and 160 micrograms/kg/min] or dipyridamole, and rapid atrial pacing (220/min). Technetium-99m-teboroxime clearance in normal myocardium was accelerated by adenosine and by dipyridamole compared to the control state (8.9 +/- 1.1 and 9.3 +/- 1.9 min versus 11.9 +/- 1.8 min; p less than 0.05). Post-stenotic 99mTc-teboroxime clearance half-time was most significantly prolonged compared to nonoccluded contralateral perfusion zones by 160 micrograms/kg/min adenosine stress (11.2 +/- 3.7 versus 6.3 +/- 1.5 min) and by complete coronary occlusion (12.1 +/- 3.3 versus 6.6 +/- 1.2 min; both p less than 0.05). Differential tracer clearance from post-stenotic versus nonoccluded zones produced quantitative evidence of relative defect "redistribution" in 71% of maximal stress studies at a mean of 8.8 +/- 2.5 min postinjection. Sensitivity, specificity, and diagnostic accuracy of prolonged regional 99mTc-teboroxime clearance rates for post-stenotic perfusion abnormalities were 62%, 100% and 81% in maximal stress studies. Future clinical trials of exercise and nonexercise stress 99mTc-teboroxime imaging should consider these kinetic characteristics and examine the correlates of perfusion defect "redistribution."

Myocardial clearance kinetics of technetium-99m-SQ30217: a marker of regional myocardial blood flow.

SQ30217 is a new, technetium-99m-(99mTc) labeled perfusion agent introduced for cardiac imaging. To evaluate the myocardial tracer kinetics, 99mTc-SQ30217, was injected intracoronarily in open-chested dogs under baseline conditions and after administration of intravenous (i.v.) dipyridamole. Myocardial first-pass retention fraction averaged 0.90 +/- 0.04. Clearance of the tracer occurred in a biexponential manner. Sixty-seven percent of retained activity cleared with a half-time of 2.3 +/- 0.6 min, while the residual activity demonstrated slow clearance. The clearance rate of the rapid phase correlated with myocardial blood flow (r = 0.72, p less than 0.001). Myocardial SQ30217 clearance rate following i.v. injection as determined by dynamic imaging with tomography (SPRINT) averaged 21 +/- 4 min and increased to 13 +/- 4 min following dipyridamole. Thus, 99mTc-SQ30217 is a promising flow tracer with high initial myocardial retention and rapid tissue clearance, which allow repeated flow determinations within short time intervals using advanced SPECT technology.

PET perfusion and vasodilator function after angioplasty for acute myocardial infarction.

UNLABELLED: The aims of this study were to validate invasive coronary Doppler flows against noninvasive PET assessments of myocardial perfusion and to examine the timing and degree of regional coronary vasodilator reserve recovery in patients who are successfully reperfused with primary angioplasty (PTCA) for acute myocardial infarction. METHODS: PTCA was performed in 21 consecutive patients with acute myocardial infarction; the final diameter stenosis was 25% +/- 7%. After restoration of TIMI Grade 3 flow, all patients underwent quantitative coronary angiography and distal Doppler coronary blood flow studies (basal and after adenosine-induced hyperemia) in the infarct and noninfarct vessels. Regional myocardial perfusion and vasodilator function were quantitated after intravenous adenosine infusion PET in all patients at 26 +/- 9 hr after acute PTCA. These were repeated in 17 patients 9 +/- 3 days later. RESULTS: Post-PTCA resting coronary flow was 35 +/- 15 ml/min in the infarct-related vessels and 50 +/- 24 ml/min during peak hyperemia (p < 0.05). Coronary flow reserve (CFR) was 1.48 +/- 0.34 and 2.08 +/- 0.62 in the infarct and noninfarct vessels, respectively (p < 0.001). Early (< 36 hr) PET myocardial perfusion reserves (MPR) in the infarct and noninfarct regions were 1.59 +/- 0.33 and 2.03 +/- 0.62 (p < 0.01). Doppler CFR and PET MPR were correlated in the infarct (r = 0.61, p < 0.01) and noninfarct (r = 0.77, p < 0.0001) regions. Follow-up PET studies demonstrated improved MPR in both infarct and noninfarct regions (1.93 +/- 0.52 versus 2.54 +/- 0.97, p < 0.01). The improvement in coronary vasodilator function from the time of acute PTCA to follow-up PET in the infarct region was significant (p = 0.005). CONCLUSION: After successful mechanical revascularization by PTCA after acute myocardial infarction, intracoronary Doppler blood flows and noninvasive PET regional myocardial perfusion are correlated within the wide range of reperfusion blood flows observed in patients with contrast angiographic TIMI Grade 3 flow. Serial PET studies demonstrated a trend towards continued improvement in the vasodilator response in infarct-related myocardial regions after the restoration of blood flow by PTCA. PET offers the potential for accurate noninvasive serial assessment of reperfusion blood flow after primary angioplasty for acute myocardial infarction.

Comparison of rubidium-82 positron emission tomography and thallium-201 SPECT imaging for detection of coronary artery disease.

The diagnostic performance of rubidium-82 (Rb-82) positron emission tomography (PET) and thallium-201 (Tl-201) single-photon emission-computed tomography (SPECT) for detecting coronary artery disease was investigated in 81 patients (52 men, 29 women). PET studies using 60 mCi of Rb-82 were performed at baseline and after intravenous infusion of 0.56 mg/kg dipyridamole in conjunction with handgrip stress. Tl-201 SPECT was performed after dipyridamole-handgrip stress and, in a subset of patients, after treadmill exercise. Sensitivity, specificity and overall diagnostic accuracy were assessed using both visually and quantitatively interpreted coronary angiograms. The overall sensitivity, specificity and accuracy of PET for detection of coronary artery disease (greater than 50% diameter stenosis) were 84, 88 and 85%, respectively. In comparison, the performance of SPECT revealed a sensitivity of 84%, specificity of 53% (p less than 0.05 vs PET) and accuracy of 79%. Similar results were obtained using either visual or quantitative angiographic criteria for severity of coronary artery disease. In 43 patients without prior myocardial infarction, the sensitivity for detection of disease was 71 and 73%, respectively, similar for both PET and SPECT. There was no significant difference in diagnostic performance between imaging modalities when 2 different modes of stress (exercise treadmill vs intravenous dipyridamole plus handgrip) were used with SPECT imaging. Thus, Rb-82 PET provides improved specificity compared with Tl-201 SPECT for identifying coronary artery disease, most likely due to the higher photon energy of Rb-82 and attenuation correction provided by PET. However, post-test referral cannot be entirely excluded as a potential explanation for the lower specificity of Tl-201 SPECT.