Myocardial Blood Flow by Magnetic Resonance in Patients With Suspected Coronary Stenosis: Comparison to PET and Invasive Physiology.

BACKGROUND: Despite recent guideline recommendations, quantitative perfusion (QP) estimates of myocardial blood flow from cardiac magnetic resonance (CMR) have only been sparsely validated. Furthermore, the additional diagnostic value of utilizing QP in addition to the traditional visual expert interpretation of stress-perfusion CMR remains unknown. The aim was to investigate the correlation between myocardial blood flow measurements estimated by CMR, positron emission tomography, and invasive coronary thermodilution. The second aim is to investigate the diagnostic performance of CMR-QP to identify obstructive coronary artery disease (CAD). METHODS: Prospectively enrolled symptomatic patients with >50% diameter stenosis on computed tomography angiography underwent dual-bolus CMR and positron emission tomography with rest and adenosine-stress myocardial blood flow measurements. Subsequently, an invasive coronary angiography (ICA) with fractional flow reserve and thermodilution-based coronary flow reserve was performed. Obstructive CAD was defined as both anatomically severe (>70% diameter stenosis on quantitative coronary angiography) or hemodynamically obstructive (ICA with fractional flow reserve ≤0.80). RESULTS: About 359 patients completed all investigations. Myocardial blood flow and reserve measurements correlated weakly between estimates from CMR-QP, positron emission tomography, and ICA-coronary flow reserve (r<0.40 for all comparisons). In the diagnosis of anatomically severe CAD, the interpretation of CMR-QP by an expert reader improved the sensitivity in comparison to visual analysis alone (82% versus 88% [P=0.03]) without compromising specificity (77% versus 74% [P=0.28]). In the diagnosis of hemodynamically obstructive CAD, the accuracy was only moderate for a visual expert read and remained unchanged when additional CMR-QP measurements were interpreted. CONCLUSIONS: CMR-QP correlates weakly to myocardial blood flow measurements by other modalities but improves diagnosis of anatomically severe CAD. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT03481712.

Impact of Absolute Myocardial Blood Flow Quantification on the Diagnostic Performance of PET-Based Perfusion Scans Using 82Rubidium.

BACKGROUND: Guidelines propose the inclusion of quantitative measurements from 82Rubidium positron emission tomography (RbPET) to discriminate obstructive coronary artery disease (CAD). However, the effect on diagnostic accuracy is unknown. The aim was to investigate the optimal RbPET reading algorithm for improved identification of obstructive CAD. METHODS: Prospectively enrolled patients (N=400) underwent RbPET and invasive coronary angiography with fractional flow reserve and quantitative coronary angiography. Quantitative measurements (myocardial blood flow (MBF), MBF reserve, transient ischemic dilatation) by RbPET were step-wisely added to a qualitative assessment by the summed stress score based on their diagnostic accuracy of obstructive CAD by invasive coronary angiography-fractional flow reserve. Prespecified cutoffs were summed stress score ≥4, hyperemic MBF 2.00 mL/g per min, and MBF reserve 1.80, respectively. Hemodynamically obstructive CAD was defined as >90% diameter stenosis or invasive coronary angiography-fractional flow reserve ≤0.80, and sensitivity analyses included a clinically relevant reference of anatomically severe CAD (>70% diameter stenosis by invasive coronary angiography-quantitative coronary angiography). RESULTS: Hemodynamically obstructive CAD was present in 170/400 (42.5%) patients. Stand-alone summed stress score showed a sensitivity and specificity of 57% and 93%, respectively, while hyperemic MBF showed similar sensitivity (61%, P=0.57) but lower specificity (85%, P=0.008). With increased discrimination by receiver-operating characteristic curves (0.78 versus 0.85; P<0.001), combining summed stress score, MBF and MBF reserve showed the highest sensitivity of 77% but lower specificity of 74% (P<0.001 for both comparisons). Against anatomically severe CAD, all measures independently yielded high discrimination ≥0.90 with increased sensitivity and lower specificity by additional quantification. CONCLUSIONS: The inclusion of quantitative measurements to a RbPET read increases in the identification of obstructive CAD. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT03481712.

ChatGPT- versus human-generated answers to frequently asked questions about diabetes: A Turing test-inspired survey among employees of a Danish diabetes center.

Large language models have received enormous attention recently with some studies demonstrating their potential clinical value, despite not being trained specifically for this domain. We aimed to investigate whether ChatGPT, a language model optimized for dialogue, can answer frequently asked questions about diabetes. We conducted a closed e-survey among employees of a large Danish diabetes center. The study design was inspired by the Turing test and non-inferiority trials. Our survey included ten questions with two answers each. One of these was written by a human expert, while the other was generated by ChatGPT. Participants had the task to identify the ChatGPT-generated answer. Data was analyzed at the question-level using logistic regression with robust variance estimation with clustering at participant level. In secondary analyses, we investigated the effect of participant characteristics on the outcome. A 55% non-inferiority margin was pre-defined based on precision simulations and had been published as part of the study protocol before data collection began. Among 311 invited individuals, 183 participated in the survey (59% response rate). 64% had heard of ChatGPT before, and 19% had tried it. Overall, participants could identify ChatGPT-generated answers 59.5% (95% CI: 57.0, 62.0) of the time, which was outside of the non-inferiority zone. Among participant characteristics, previous ChatGPT use had the strongest association with the outcome (odds ratio: 1.52 (1.16, 2.00), p = 0.003). Previous users answered 67.4% (61.7, 72.7) of the questions correctly, versus non-users' 57.6% (54.9, 60.3). Participants could distinguish between ChatGPT-generated and human-written answers somewhat better than flipping a fair coin, which was against our initial hypothesis. Rigorously planned studies are needed to elucidate the risks and benefits of integrating such technologies in routine clinical practice.

Danish study of Non-Invasive Testing in Coronary Artery Disease 3 (Dan-NICAD 3): study design of a controlled study on optimal diagnostic strategy.

INTRODUCTION: Current guideline recommend functional imaging for myocardial ischaemia if coronary CT angiography (CTA) has shown coronary artery disease (CAD) of uncertain functional significance. However, diagnostic accuracy of selective myocardial perfusion imaging after coronary CTA is currently unclear. The Danish study of Non-Invasive testing in Coronary Artery Disease 3 trial is designed to evaluate head to head the diagnostic accuracy of myocardial perfusion imaging with positron emission tomography (PET) using the tracers 82Rubidium (82Rb-PET) compared with oxygen-15 labelled water PET (15O-water-PET) in patients with symptoms of obstructive CAD and a coronary CT scan with suspected obstructive CAD. METHODS AND ANALYSIS: This prospective, multicentre, cross-sectional study will include approximately 1000 symptomatic patients without previous CAD. Patients are included after referral to coronary CTA. All patients undergo a structured interview and blood is sampled for genetic and proteomic analysis and a coronary CTA. Patients with possible obstructive CAD at coronary CTA are examined with both 82Rb-PET, 15O-water-PET and invasive coronary angiography with three-vessel fractional flow reserve and thermodilution measurements of coronary flow reserve. After enrolment, patients are followed with Seattle Angina Questionnaires and follow-up PET scans in patients with an initially abnormal PET scan and for cardiovascular events in 10 years. ETHICS AND DISSEMINATION: Ethical approval was obtained from Danish regional committee on health research ethics. Written informed consent will be provided by all study participants. Results of this study will be disseminated via articles in international peer-reviewed journal. TRIAL REGISTRATION NUMBER: NCT04707859.

Second-Line Myocardial Perfusion Imaging to Detect Obstructive Stenosis: Head-to-Head Comparison of CMR and PET.

BACKGROUND: Guidelines recommend verification of myocardial ischemia by selective second-line myocardial perfusion imaging (MPI) following a coronary computed tomography angiography (CTA) with suspected obstructive coronary artery disease (CAD). Head-to-head data on the diagnostic performance of different MPI modalities in this setting are sparse. OBJECTIVES: The authors sought to compare, head-to-head, the diagnostic performance of selective MPI by 3.0-T cardiac magnetic resonance (CMR) and 82rubidium positron emission tomography (RbPET) in patients with suspected obstructive stenosis at coronary CTA using invasive coronary angiography (ICA) with fractional flow reserve (FFR) as reference. METHODS: Consecutive patients (n = 1,732, mean age: 59.1 ± 9.5 years, 57.2% men) referred for coronary CTA with symptoms suggestive of obstructive CAD were included. Patients with suspected stenosis were referred for both CMR and RbPET and subsequently ICA. Obstructive CAD was defined as FFR ≤0.80 or >90% diameter stenosis by visual assessment. RESULTS: In total, 445 patients had suspected stenosis on coronary CTA. Of these, 372 patients completed both CMR, RbPET and subsequent ICA with FFR. Hemodynamically obstructive CAD was identified in 164 of 372 (44.1%) patients. Sensitivities for CMR and RbPET were 59% (95% CI: 51%-67%) and 64% (95% CI: 56%-71%); P = 0.21, respectively, and specificities 84% (95% CI: 78%-89%) and 89% (95% CI: 84%-93%]); P = 0.08, respectively. Overall accuracy was higher for RbPET compared with CMR (73% vs 78%; P = 0.03). CONCLUSIONS: In patients with suspected obstructive stenosis at coronary CTA, CMR, and RbPET show similar and moderate sensitivities but high specificities compared with ICA with FFR. This patient group represents a diagnostic challenge with frequent mismatch between advanced MPI tests and invasive measurements. (Danish Study of Non-Invasive Diagnostic Testing in Coronary Artery Disease 2 [Dan-NICAD 2]; NCT03481712).

Workplace Violence and Long-term Sickness Absence: Assessment of the Potential Buffering Effect of Social Support in Two Occupational Cohort Studies.

OBJECTIVES: We aimed to determine the effect of workplace violence on long-term sickness absence, and whether social support from supervisors and colleagues buffer this effect. METHODS: Information on workplace violence and social support were derived from the Danish Work Environment Cohort Study in 2000, 2005, and 2010 and the Swedish Longitudinal Occupational Survey of Health in 2006 and 2008. Individual- and joint-effects on register-based long-term sickness absence were determined using logistic regression models for repeated measurements. Cohort-specific estimates were combined in random effect meta-analyses. RESULTS: Workplace violence and low social support were independently associated with a higher risk of long-term sickness absence, and we did not find evidence of an interaction. CONCLUSION: Exposure to workplace violence is a risk factor for long-term sickness absence while social support is associated with a lower risk of long-term sickness absence.

Construct and content validity of the Functional Oral Intake Scale; Analyses from a cohort of patients with acquired brain injury.

OBJECTIVE: To investigate the construct validity of the Functional Oral Intake Scale (FOIS) as a proxy measure for dysphagia, through associations with swallowing prerequisites, orofacial functions, age, and diagnosis; and to investigate content validity through distributions of FOIS ratings. METHODS: A cohort of 1,876 patients with severe acquired brain injury. Early Functional Abilities items were applied as measures of swallowing prerequisites and orofacial functions. Clustered logistic regression model with 6,052 cross-sectional observations. RESULTS: Disturbance in swallowing 10.55 OR (95%CI:7.90;14.09), oro-facial stimulation 3.04 OR (95%CI:2.41;3.83), and head control 2.86 OR (95%CI:2.25;3.62) were robustly associated with tube feeding (FOIS 1-3). Disturbance in trunk control, wakefulness, tongue movement/chewing, older age, and a non-stroke diagnosis were also associated with tube feeding. BMI did not attenuate associations in sensitivity analyses. FOIS ratings had greatest density in FOIS level 1 and level 7, with 25% and 40% of registrations, respectively. Level 4 was rated in only 1% of 6,052 registrations. CONCLUSIONS: The FOIS was robustly associated with indicators of dysphagia. However, associations with postural control, wakefulness, age and diagnosis highlights that tube feeding may be attributed to other issues than dysphagia. It should be further investigated whether FOIS level 4 is meaningful in neurorehabilitation.

Using Routinely Gathered Clinical Data to Develop a Prognostic Online Tool for Decannulation in Subjects With Acquired Brain Injury.

BACKGROUND: Clinicians are often required to provide a qualified guess on the probability of decannulation in estimating patients' rehabilitation potential and relaying information about prognosis to patients and next of kin. The objective of this study was to use routinely gathered clinical data to develop a prognostic model of time to decannulation in subjects with acquired brain injury, for direct implementation in clinical practice. METHODS: Data from a large cohort including 574 tracheostomized subjects admitted for neurorehabilitation were analyzed using discrete time-to-event analysis with logit-link. Within this model, a reference hazard function was modeled using restricted cubic splines, and estimates were presented using odds ratios (95% CIs). RESULTS: A total of 411 subjects (72%) were decannulated within a median of 27 d (interquartile range 16-49) at the rehabilitation hospital. The prognostic model for decannulation included age, diagnosis, days from injury until admission for rehabilitation, swallowing, and overall functional level measured with the Early Functional Abilities score. Among these, the strongest predictors for decannulation were age and a combination of overall functional abilities combined with swallowing ability. CONCLUSIONS: A prognostic model for decannulation was developed using routinely gathered clinical data. Based on the model, an online graphical user interface was applied, in which the probability of decannulation within x days is calculated along with the statistical uncertainty of the probability. Furthermore, a layman's interpretation is provided. The online tool was directly implemented in clinical practice at the rehabilitation hospital, and is available through this link: (http://www.hospitalsenhedmidt.dk/regionshospitalet-hammel/research-unit/Prognosissoftware/).

Observer Agreement and Accuracy of 18F-Sodium Fluoride PET/CT in the Diagnosis of Bone Metastases in Prostate Cancer.

Our aim was to evaluate the interobserver agreement in 18F-sodium fluoride (NaF) PET/CT for the detection of bone metastases in patients with prostate cancer (PCa). Methods:18F-NaF PET/CT scans were retrieved from all patients who participated in 4 recent prospective trials. Two experienced observers independently evaluated the 18F-NaF PET/CT scans on a patient level using a 3-category scale (no bone metastases [M0], equivocal for bone metastases, and bone metastases present [M1]) and on a dichotomous scale (M0/M1). In patients with no more than 10 lesions, the location and number of lesions were recorded. On a patient level, the diagnostic performance was calculated using a sensitivity analysis, in which equivocal lesions were handled as M0 as well as M1. Results:18F-NaF PET/CT scans from 219 patients with PCa were included, of whom 129 patients were scanned for primary staging, 67 for biochemical recurrence, and 23 for metastatic castration-resistant PCa. Agreement between the observers was almost perfect on a patient level (3-category unweighted κ = 0.83 ± 0.05, linear weighted κ = 0.90 ± 0.06, and dichotomous κ = 0.91 ± 0.07). On a lesion level (dichotomous scale), the observers agreed on the number and location of bone metastases in 205 (93.6%) patients. In the remaining 14 patients, the readers disagreed on the number of lesions in 13 patients and the location of bone metastases in 1 patient. A final diagnosis of bone metastases was made for 211 of 219 patients. The sensitivity ranged from 0.86 to 0.92, specificity from 0.83 to 0.97, positive predictive value from 0.70 to 0.93, and negative predictive value from 0.94 to 0.96. Conclusion: The interobserver agreement on 18F-NaF PET/CT for the detection of bone metastases in patients with PCa was very high among trained observers, both on a patient level and on a lesion level. Moreover, the diagnostic performance of 18F-NaF PET/CT was satisfactory, rendering 18F-NaF PET/CT a robust tool in the diagnostic armamentarium.

No Added Value of 18F-Sodium Fluoride PET/CT for the Detection of Bone Metastases in Patients with Newly Diagnosed Prostate Cancer with Normal Bone Scintigraphy.

The aim of this study was to determine if additional 18F-sodium fluoride PET/CT (NaF PET/CT) improves the prognostic accuracy in the initial staging of prostate cancer patients with normal bone scintigraphy undergoing prostatectomy. Methods: A prospective cohort study examined NaF PET/CT in intermediate- or high-risk prostate cancer with negative bone scintigraphy who were scheduled for prostatectomy. Biochemical response: PSA levels < 0.2 ng/mL at 6 wk and 6 mo postoperatively, PSA level ≥ 0.2 ng/mL was biochemical failure. Results: Eighty-one patients were included in the study; 75 patients (93%) achieved biochemical responses, 6 patients had biochemical failure. NaF PET/CT indicated bone metastasis in 1 patient (1.2%), was equivocal in 7 patients (8.6%), without bone metastases in 73 patients (90.1%). Eight patients with bone metastases or equivocal results on NaF PET/CT exhibited biochemical responses. All patients with biochemical failure had negative NaF PET/CT and bone scintigraphy for bone metastases. Conclusion: NaF PET/CT has no added value for bone staging in intermediate- and high-risk prostate cancer patients with normal bone scintigraphy results undergoing prostatectomy.

Lower Bowel Dysfunction Following Acquired Brain Injury: A Challenge During Rehabilitation.

The aim of this prospective, descriptive cohort study is to describe the prevalence of lower bowel dysfunction, possible relationship to diagnosis and severity, use of laxatives, and defecation patterns in patients with acquired brain injury during inpatient rehabilitation. Enrollment consisted of all patients admitted to an inpatient rehabilitation hospital (n = 98) within a 3-month period and assessments of fecal incontinence and fecal constipation at admission were performed. Documentation of used laxatives, number of defecations, and the macroscopic form during 4 weeks was conducted. Analysis of variance and Kruskal-Wallis analyses were conducted using the statistical software package STATA v 12/IC. At admission 75% of the patients suffered from lower bowel dysfunction, which was related to the severity of injury and age but not major diagnosis or gender. Of these, 68% suffered from fecal incontinence and 32% from fecal constipation. Ninety percent of the patients received laxatives during the initial 28 days. After 28 days, 20% continued to receive laxative treatment. There was no difference between weekly defecations in patients who had functional constipation and patients who had no bowel dysfunction. There was a strong relationship between bowel dysfunction status and prescribed laxative treatment. These findings indicate that lower gastrointestinal dysfunction is a long-lasting, profound complication following an acquired brain injury.

Informal caregiving and diurnal patterns of salivary cortisol: Results from the Whitehall II cohort study.

The objective was to investigate the relationship between various aspects of informal caregiving and diurnal patterns of salivary cortisol, with special attention to the moderating effect of sex and work status. The study population was composed of 3727 men and women from the British Whitehall II study. Salivary cortisol was measured six times during a weekday. Aspects of caregiving included the relationship of caregiver to recipient, weekly hours of caregiving, and length of caregiving. Diurnal cortisol profiles were assessed using the cortisol awakening response (CAR) and diurnal cortisol slopes. Results showed that men, but not women, providing informal care had a blunted CAR compared with non-caregivers (PInteraction = 0.03). Furthermore, we found a dose-response relationship showing that more weekly hours of informal care was associated with a more blunted CAR for men (Ptrend = 0.03). Also, the blunted CAR for men was especially pronounced in short-term caregivers and those in paid work. In women, the steepest cortisol slope was seen among those in paid work who provided informal care (PInteraction = 0.01). To conclude, we found different cortisol profiles in male and female informal caregivers. Male caregivers had a blunted CAR, which has previously been associated with chronic stress and burnout. Future research should investigate whether results are generalizable beyond UK citizens with a working history in the civil service.

Prospective comparative study of 18F-sodium fluoride PET/CT and planar bone scintigraphy for treatment response assessment of bone metastases in patients with prostate cancer.

AIM: To compare 18F-sodium fluoride positron emission tomography/computed tomography (NaF PET/CT) and 99mTc-labelled diphosphonate bone scan (BS) for the monitoring of bone metastases in patients with prostate cancer undergoing anti-cancer treatment. MATERIAL AND METHODS: Data from 64 patients with prostate cancer were included. The patients received androgen-deprivation therapy (ADT), next-generation hormonal therapy (NGH) or chemotherapy. The patients had a baseline scan and 1-3 subsequent scans during six months of treatment. Images were evaluated by experienced nuclear medicine physicians and classified for progressive disease (PD) or non-PD according to the Prostate Cancer Working Group 2 (PCWG-2) criteria. The patients were also classified as having PD/non-PD according to the clinical and prostate-specific antigen (PSA) responses. RESULTS: There was no difference between NaF PET/CT and BS in the detection of PD and non-PD during treatment (McNemar's test, p = .18). The agreement between BS and NaF PET/CT for PD/non-PD was moderate (Cohen's kappa 0.53, 95% confidence interval 0.26-0.79). Crude agreement between BS and NaF PET/CT for the assessment of PD/non-PD was 86% (89% for ADT, n = 28; 88% for NGH, n = 16, and 80% for chemotherapy, n = 20). In most discordant cases, BS found PD when NaF PET/CT did not, or BS detected PD on an earlier scan than NaF PET/CT. Biochemical progression (27%) occurred more frequently than progression on functional imaging (BS, 22% and NaF PET/CT, 14%). Clinical progression was rare (11%), and almost exclusively seen in patients receiving chemotherapy. CONCLUSION: There was no difference between NaF PET/CT and BS in the detection of PD and non-PD; however, BS seemingly detects PD by the PCWG-2 criteria earlier than NaF-PET, which might be explained by the fact that NaF-PET is more sensitive at the baseline scan.

Acute Appendicitis as the Initial Clinical Presentation of Primary HIV-1 Infection.

We report a case of an adolescent who presented at our emergency department with acute abdominal pain. While the initial diagnosis was acute appendicitis, a secondary and coincidental diagnosis of primary HIV-1 infection was made. Concurrent and subsequent clinical and molecular biology findings form the basis of our argument that primary HIV-1 infection was the cause of acute appendicitis in this individual.

Weekly hours of informal caregiving and paid work, and the risk of cardiovascular disease.

Background: Little is known on the association between weekly hours of informal caregiving and risk of cardiovascular disease (CVD). The objective was to investigate the individual and joint effects of weekly hours of informal caregiving and paid work on the risk of CVD. Methods: Pooled analysis with 1396 informal caregivers in gainful employment, from the Swedish Longitudinal Occupational Survey of Health and the Whitehall II study. Informal caregiving was defined as care for an aged or disabled relative. The outcome was CVD during 10 years follow-up. Analyzes were adjusted for age, sex, children, marital status and occupational grade. Results: There were 59 cases of CVD. Providing care >20 h weekly were associated with a higher risk of CVD compared to those providing care 1-8 h weekly (hazard ratio = 2.63, 95%CI: 1.20; 5.76), irrespectively of weekly work hours. In sensitivity analyzes, we found this risk to be markedly higher among long-term caregivers (6.17, 95%CI: 1.73; 22.1) compared to short-term caregivers (0.89, 95%CI: 0.10; 8.08). Caregivers working ≥55 h weekly were at higher risk of CVD (2.23, 95%CI: 1.14; 4.35) compared to those working 35-40 h weekly. Those providing care >8 h and working ≤40 h weekly had a higher risk of CVD compared to those providing care 1-8 h and working ≤40 h (3.23, 95%CI: 1.25; 8.37). Conclusion: A high number of weekly hours of informal caregiving as opposed to few weekly hours is associated with a higher risk of CVD, irrespectively of weekly work hours. The excess risk seemed to be driven by those providing care over long periods of time.

Effects of sodium nitrite on renal function and blood pressure in hypertensive vs. healthy study participants: a randomized, placebo-controlled, crossover study.

OBJECTIVE: Nitric oxide is a key player in regulating vascular tone. Impaired endothelial nitric oxide synthesis plays an important role in hypertension. Replenishing of nitric oxide by sodium nitrite (NaNO2) has not been investigated in patients with essential hypertension (EHT). We aimed to determine the effects of NaNO2 on blood pressure (BP) and renal sodium and water regulation in patients with EHT compared with healthy control study participants (CON). METHODS: In a placebo-controlled, crossover study, we infused 240 µg NaNO2/kg/h or isotonic saline for 2 h in 14 EHT and 14 CON. During infusion, we measured changes in brachial and central BP, free water clearance, fractional sodium excretion, and urinary excretion rate of γ-subunit of the epithelial sodium channel (U-ENaCγ), and aquaporin-2 (U-AQP2). RESULTS: Placebo-adjusted brachial SBP decreased 18 mmHg (P < 0.001) during NaNO2 infusion in EHT and 12 mmHg (P < 0.001) in CON (Pbetween = 0.024). Brachial DBP and central SBP decreased equally in both groups during NaNO2. In EHT, we found a decrease in U-ENaCγ during NaNO2 infusion. In both groups, we observed a decrease in fractional sodium excretion, free water clearance, and U-AQP2 during NaNO2 infusion. CONCLUSION: This study demonstrated an augmented BP-lowering effect of NaNO2 in patients with EHT. We observed an antinatriuretic and antidiuretic effect of NaNO2 in both groups, and a decrease in U-ENaCγ, solely in EHT. In both groups, we detected a nonvasopressin mediated decrease in U-AQP2, which is most likely compensatory to the decline in diuresis.

Diagnostic test accuracy study of 18F-sodium fluoride PET/CT, 99mTc-labelled diphosphonate SPECT/CT, and planar bone scintigraphy for diagnosis of bone metastases in newly diagnosed, high-risk prostate cancer.

The aim of this study was to prospectively compare planar, bone scan (BS) versus SPECT/CT and NaF PET/CT in detecting bone metastases in prostate cancer. Thirty-seven consecutive, newly diagnosed, prostate cancer patients with prostate specific antigen (PSA) levels ≥ 50 ng/mL and who were considered eligible for androgen-deprivation therapy (ADT) were included in this study. BS, SPECT/CT, and NaF PET/CT, were performed prior to treatment and were repeated after six months of ADT. Baseline images from each index test were independently read by two experienced readers. The reference standard was based on a consensus decision made by a multidisciplinary team on the basis of baseline and follow-up images of the index tests, the findings of the baseline index tests by the experienced readers, and any available imaging, biochemical, and clinical data, including the response to ADT. Twenty-seven (73%) of the 37 patients had bone metastases according to the reference standard. The sensitivities for BS, SPECT/CT and NaF PET/CT were 78%, 89%, and 89%, respectively, and the specificities were 90%, 100%, and 90%, respectively. The positive predictive values of BS, SPECT/CT and NaF PET/CT were 96%, 100%, and 96%, respectively, and the negative predictive values were 60%, 77% and 75%, respectively. No statistically significant difference among the three imaging modalities was observed. All three imaging modalities showed high sensitivity and specificity. NaF PET/CT and SPECT/CT showed numerically improved, but not statistically superior, sensitivity compared with BS in this limited and selected patient cohort.

Stress-only myocardial perfusion scintigraphy: a prospective study on the accuracy and observer agreement with quantitative coronary angiography as the gold standard.

OBJECTIVE: Patients with normal stress perfusion have an excellent prognosis. Prospective studies on the diagnostic accuracy of stress-only scans with contemporary, independent examinations as gold standards are lacking. PATIENTS AND METHODS: A total of 109 patients with typical angina and no previous coronary artery disease underwent a 2-day stress (exercise)/rest, gated, and attenuation-corrected (AC), 99m-technetium-sestamibi perfusion study, followed by invasive coronary angiography. The stress datasets were evaluated twice by four physicians with two different training levels (expert and novice): familiar and unfamiliar with AC. The two experts also made a consensus reading of the integrated stress-rest datasets. The consensus reading and quantitative data from the invasive coronary angiography were applied as reference methods. RESULTS: The sensitivity/specificity were 0.92-1.00/0.73-0.90 (reference: expert consensus reading), 0.93-0.96/0.63-0.82 (reference: ≥1 stenosis>70%), and 0.75-0.88/0.70-0.88 (reference: ≥1 stenosis>50%). The four readers showed a high and fairly equal sensitivity independent of their familiarity with AC. The expert familiar with AC had the highest specificity independent of the reference method. The intraobserver and interobserver agreements on the stress-only readings were good (readers without AC experience) to excellent (readers with AC experience). CONCLUSION: AC stress-only images yielded a high sensitivity independent of the training level and experience with AC of the nuclear physician, whereas the specificity correlated positively with both. Interobserver and intraobserver agreements tended to be the best for physicians with AC experience.