68Ga-Prostate-specific membrane antigen (PSMA) positron emission tomography (pet) in prostate cancer: a systematic review and meta-analysis

ABSTRACT Introduction: Prostate cancer (PC) is the second most commonly diagnosed cancer in males. 68Ga-PSMA PET/CT, a non-invasive diagnostic tool to evaluate PC with prostate-specific membrane antigen (PSMA) expression, has emerged as a more accurate alternative to assess disease staging. We aimed to identify predictors of positive 68Ga-PSMA PET and the accuracy of this technique. Materials and methods: Diagnostic accuracy cross-sectional study with prospective and retrospective approaches. We performed a comprehensive literature search on PubMed, Cochrane Library, and Embase database in search of studies including PC patients submitted to radical prostatectomy or radiotherapy with curative intent and presented biochemical recurrence following ASTRO 1996 criteria. A total of 35 studies involving 3910 patients submitted to 68-Ga-PSMA PET were included and independently assessed by two authors: 8 studies on diagnosis, four on staging, and 23 studies on restaging purposes. The significance level was α=0.05. Results: pooled sensitivity and specificity were 0.90 (0.86-0.93) and 0.90 (0.82-0.96), respectively, for diagnostic purposes; as for staging, pooled sensitivity and specificity were 0.93 (0.86-0.98) and 0.96 (0.92-0.99), respectively. In the restaging scenario, pooled sensitivity and specificity were 0.76 (0.74-0.78) and 0.45 (0.27-0.58), respectively, considering the identification of prostate cancer in each described situation. We also obtained specificity and sensitivity results for PSA subdivisions. Conclusion: 68Ga-PSMA PET provides higher sensitivity and specificity than traditional imaging for prostate cancer.

68Ga-Prostate-specific membrane antigen (psma) positron emission tomography (pet) in prostate cancer: a systematic review and meta-analysis.

INTRODUCTION: Prostate cancer (PC) is the second most commonly diagnosed cancer in males. 68Ga-PSMA PET/CT, a non-invasive diagnostic tool to evaluate PC with prostate-specific membrane antigen (PSMA) expression, has emerged as a more accurate alternative to assess disease staging. We aimed to identify predictors of positive 68Ga-PSMA PET and the accuracy of this technique. MATERIALS AND METHODS: Diagnostic accuracy cross-sectional study with prospective and retrospective approaches. We performed a comprehensive literature search on PubMed, Cochrane Library, and Embase database in search of studies including PC patients submitted to radical prostatectomy or radiotherapy with curative intent and presented biochemical recurrence following ASTRO 1996 criteria. A total of 35 studies involving 3910 patients submitted to 68-Ga-PSMA PET were included and independently assessed by two authors: 8 studies on diagnosis, four on staging, and 23 studies on restaging purposes. The significance level was α=0.05. RESULTS: pooled sensitivity and specificity were 0.90 (0.86-0.93) and 0.90 (0.82-0.96), respectively, for diagnostic purposes; as for staging, pooled sensitivity and specificity were 0.93 (0.86-0.98) and 0.96 (0.92-0.99), respectively. In the restaging scenario, pooled sensitivity and specificity were 0.76 (0.74-0.78) and 0.45 (0.27-0.58), respectively, considering the identification of prostate cancer in each described situation. We also obtained specificity and sensitivity results for PSA subdivisions. CONCLUSION: 68Ga-PSMA PET provides higher sensitivity and specificity than traditional imaging for prostate cancer.

Diagnostic performance of an artificial intelligence-driven cardiac-structured reporting system for myocardial perfusion SPECT imaging.

OBJECTIVES: To describe and validate an artificial intelligence (AI)-driven structured reporting system by direct comparison of automatically generated reports to results from actual clinical reports generated by nuclear cardiology experts. BACKGROUND: Quantitative parameters extracted from myocardial perfusion imaging (MPI) studies are used by our AI reporting system to generate automatically a guideline-compliant structured report (sR). METHOD: A new nonparametric approach generates distribution functions of rest and stress, perfusion, and thickening, for each of 17 left ventricle segments that are then transformed to certainty factors (CFs) that a segment is hypoperfused, ischemic. These CFs are then input to our set of heuristic rules used to reach diagnostic findings and impressions propagated into a sR referred as an AI-driven structured report (AIsR). The diagnostic accuracy of the AIsR for detecting coronary artery disease (CAD) and ischemia was tested in 1,000 patients who had undergone rest/stress SPECT MPI. RESULTS: At the high-specificity (SP) level, in a subset of 100 patients, there were no statistical differences in the agreements between the AIsr, and nine experts' impressions of CAD (P = .33) or ischemia (P = .37). This high-SP level also yielded the highest accuracy across global and regional results in the 1,000 patients. These accuracies were statistically significantly better than the other two levels [sensitivity (SN)/SP tradeoff, high SN] across all comparisons. CONCLUSIONS: This AI reporting system automatically generates a structured natural language report with a diagnostic performance comparable to those of experts.

Relapsed ovarian cancer - diagnosis using 18F-FDG PET/CT; 4.

The Guidelines Project, an initiative of the Brazilian Medical Association, aims to combine information from the medical field in order to standardize procedures to assist the reasoning and decision-making of doctors. The information provided through this project must be assessed and criticized by the physician responsible for the conduct that will be adopted, depending on the conditions and the clinical status of each patient.

Cervical cancer - staging and restaging with 18F-FDG PET/CT.

The Guidelines Project, an initiative of the Brazilian Medical Association, aims to combine information from the medical field in order to standardize producers to assist the reasoning and decision-making of doctors. The information provided through this project must be assessed and criticized by the physician responsible for the conduct that will be adopted, depending on the conditions and the clinical status of each patient.

Cervical cancer - staging and restaging with 18F-FDG PET/CT

The Guidelines Project, an initiative of the Brazilian Medical Association, aims to combine information from the medical field in order to standardize producers to assist the reasoning and decision-making of doctors. The information provided through this project must be assessed and criticized by the physician responsible for the conduct that will be adopted, depending on the conditions and the clinical status of each patient.

Relapsed ovarian cancer - diagnosis using 18F-FDG PET/CT; 4

The Guidelines Project, an initiative of the Brazilian Medical Association, aims to combine information from the medical field in order to standardize procedures to assist the reasoning and decision-making of doctors. The information provided through this project must be assessed and criticized by the physician responsible for the conduct that will be adopted, depending on the conditions and the clinical status of each patient.

Inflammatory response to mental stress and mental stress induced myocardial ischemia.

BACKGROUND: Mental stress-induced myocardial ischemia (MSIMI) is associated with increased risk of adverse cardiovascular outcomes, yet the underlying mechanisms are not well understood. We measured the inflammatory response to acute laboratory mental stress in patients with coronary artery disease (CAD) and its association with MSIMI. We hypothesized that patients with MSIMI would have a higher inflammatory response to mental stress in comparison to those without ischemia. METHODS: Patients with stable CAD underwent 99mTc sestamibi myocardial perfusion imaging during mental stress testing using a public speaking stressor. MSIMI was determined as impaired myocardial perfusion using a 17-segment model. Inflammatory markers including interleukin-6 (IL-6), monocyte chemoattractant protein-1 (MCP-1), matrix metallopeptidase 9 (MMP-9) and high-sensitivity C reactive protein (hsCRP) were measured at rest and 90 min after mental stress. Results were validated in an independent sample of 228 post-myocardial infarction patients. RESULTS: Of 607 patients analyzed in this study, (mean age 63 ±â€¯9 years, 76% male), 99 (16.3%) developed MSIMI. Mental stress resulted in a significant increase in IL-6, MCP-1, and MMP-9 (all p <0.0001), but not hsCRP. However, the changes in these markers were similar in those with and without MSIMI. Neither resting levels of these biomarkers, nor their changes with mental stress were significantly associated with MSIMI. Results in the replication sample were similar. CONCLUSION: Mental stress is associated with acute increases in several inflammatory markers. However, neither the baseline inflammatory status nor the magnitude of the inflammatory response to mental stress over 90 min were significantly associated with MSIMI.

Association Between High-Sensitivity Cardiac Troponin Levels and Myocardial Ischemia During Mental Stress and Conventional Stress.

OBJECTIVES: This study sought to investigate whether patients with mental stress-induced myocardial ischemia will have high resting and post-mental stress high-sensitivity cardiac troponin I (hs-cTnI). BACKGROUND: Hs-cTnI is a marker of myocardial necrosis, and its elevated levels are associated with adverse outcomes. Hs-cTnI levels may increase with exercise in patients with coronary artery disease. Mental stress-induced myocardial ischemia is also linked to adverse outcomes. METHODS: In this study, 587 patients with stable coronary artery disease underwent technetium Tc 99m sestamibi-single-photon emission tomography myocardial perfusion imaging during mental stress testing using a public speaking task and during conventional (pharmacological/exercise) stress testing as a control condition. Ischemia was defined as new/worsening impairment in myocardial perfusion using a 17-segment model. RESULTS: The median hs-cTnI resting level was 4.3 (interquartile range [IQR]: 2.9 to 7.3) pg/ml. Overall, 16% and 34.8% of patients developed myocardial ischemia during mental and conventional stress, respectively. Compared with those without ischemia, median resting hs-cTnI levels were higher in patients who developed ischemia either during mental stress (5.9 [IQR: 3.9 to 8.3] pg/ml vs. 4.1 [IQR: 2.7 to 7.0] pg/ml; p < 0.001) or during conventional stress (5.4 [IQR: 3.9 to 9.3] pg/ml vs. 3.9 [IQR: 2.5 to 6.5] pg/ml; p < 0.001). Patients with high hs-cTnI (cutoff of 4.6 pg/ml for men and 3.9 pg/ml for women) had greater odds of developing mental (odds ratio [OR]: 2.4; 95% confidence interval [CI]: 1.5 to 3.9; p < 0.001) and conventional (OR: 2.4; 95% CI: 1.7 to 3.4; p < 0.001) stress-induced ischemia. Although there was a significant increase in 45-min post-treadmill exercise hs-cTnI levels in those who developed ischemia, there was no significant increase after mental or pharmacological stress test. CONCLUSIONS: In patients with coronary artery disease, myocardial ischemia during either mental stress or conventional stress is associated with higher resting levels of hs-cTnI. This suggests that hs-cTnI elevation is an indicator of chronic ischemic burden experienced during everyday life. Whether elevated hs-cTnI levels are an indicator of adverse prognosis beyond inducible ischemia or whether it is amenable to intervention requires further investigation.

Zero Calcium Score as a Filter for Further Testing in Patients Admitted to the Coronary Care Unit with Chest Pain / Inferência Bayesiana quanto ao Valor do Escore de Cálcio Zero como Filtro na Investigação da Dor Torácica Aguda em Unidade Coronariana

Abstract Background: The accuracy of zero coronary calcium score as a filter in patients with chest pain has been demonstrated at the emergency room and outpatient clinics, populations with low prevalence of coronary artery disease (CAD). Objective: To test the gatekeeping role of zero calcium score in patients with chest pain admitted to the coronary care unit (CCU), where the pretest probability of CAD is higher than that of other populations. Methods: Patients underwent computed tomography for calcium scoring, and obstructive CAD was defined by a minimum 70% stenosis on invasive angiography. Results: In 146 patients studied, the prevalence of CAD was 41%. A zero calcium score was present in 35% of the patients. The sensitivity and specificity of zero calcium score yielded a negative likelihood ratio of 0.16. After logistic regression adjustment for pretest probability, zero calcium score was independently associated with lower odds of CAD (OR = 0.12, 95%CI = 0.04-0.36), increasing the area under the ROC curve of the clinical model from 0.76 to 0.82 (p = 0.006). Zero calcium score provided a net reclassification improvement of 0.20 (p = 0.0018) over the clinical model when using a pretest probability threshold of 10% for discharging without further testing. In patients with pretest probability < 50%, zero calcium score had a negative predictive value of 95% (95%CI = 83%-99%), with a number needed to test of 2.1 for obtaining one additional discharge. Conclusion: Zero calcium score substantially reduces the pretest probability of obstructive CAD in patients admitted to the CCU with acute chest pain. (Arq Bras Cardiol. 2017; [online].ahead print, PP.0-0)

Resumo Fundamento: A acurácia do escore de cálcio coronário zero como um filtro nos pacientes com dor torácica aguda tem sido demonstrada na sala de emergência e nos ambulatórios, populações com baixa prevalência de doença arterial coronariana (DAC). Objetivos: Testar o papel do escore de cálcio zero como filtro nos pacientes com dor torácica admitidos numa unidade coronariana intensiva (UCI), na qual a probabilidade pré-teste de DAC é maior do que em outras populações. Métodos: Pacientes foram submetidos a tomografia computadorizada para quantificar o escore de cálcio, DAC obstrutiva foi definida por uma estenose mínima de 70% na cineangiocoronariografia invasiva. Um escore clínico para estimar a probabilidade pré-teste de DAC obstrutiva foi criado em amostra de 370 pacientes, usado para definir subgrupos na definição de valores preditivos negativos do escore zero. Resultados: Em 146 pacientes estudados, a prevalência de DAC foi 41% e o escore de cálcio zero foi demonstrado em 35% deles. A sensibilidade e a especificidade para escore de cálcio zero resultaram numa razão de verossimilhança negativa de 0,16. Após ajuste com um escore clínico com a regressão logística para a probabilidade pré-teste, o escore de cálcio zero foi preditor independente associado a baixa probabilidade de DAC (OR = 0,12, IC95% = 0,04-0,36), aumentando a área abaixo da curva ROC do modelo clínico de 0,76 para 0,82 (p = 0,006). Considerando a probabilidade de DAC < 10% como ponto de corte para alta precoce, o escore de cálcio aumentou a proporção de pacientes para alta precoce de 8,2% para 25% (NRI = 0,20; p = 0,0018). O escore de cálcio zero apresentou valor preditivo negativo de 90%. Em pacientes com probabilidade pré-teste < 50%, o valor preditivo negativo foi 95% (IC95% = 83%-99%). Conclusão: O escore de cálcio zero reduz substancialmente a probabilidade pré-teste de DAC obstrutiva em pacientes internados em UCI com dor torácica aguda. (Arq Bras Cardiol. 2017; [online].ahead print, PP.0-0)

Zero Calcium Score as a Filter for Further Testing in Patients Admitted to the Coronary Care Unit with Chest Pain.

BACKGROUND:: The accuracy of zero coronary calcium score as a filter in patients with chest pain has been demonstrated at the emergency room and outpatient clinics, populations with low prevalence of coronary artery disease (CAD). OBJECTIVE:: To test the gatekeeping role of zero calcium score in patients with chest pain admitted to the coronary care unit (CCU), where the pretest probability of CAD is higher than that of other populations. METHODS:: Patients underwent computed tomography for calcium scoring, and obstructive CAD was defined by a minimum 70% stenosis on invasive angiography. RESULTS:: In 146 patients studied, the prevalence of CAD was 41%. A zero calcium score was present in 35% of the patients. The sensitivity and specificity of zero calcium score yielded a negative likelihood ratio of 0.16. After logistic regression adjustment for pretest probability, zero calcium score was independently associated with lower odds of CAD (OR = 0.12, 95%CI = 0.04-0.36), increasing the area under the ROC curve of the clinical model from 0.76 to 0.82 (p = 0.006). Zero calcium score provided a net reclassification improvement of 0.20 (p = 0.0018) over the clinical model when using a pretest probability threshold of 10% for discharging without further testing. In patients with pretest probability < 50%, zero calcium score had a negative predictive value of 95% (95%CI = 83%-99%), with a number needed to test of 2.1 for obtaining one additional discharge. CONCLUSION:: Zero calcium score substantially reduces the pretest probability of obstructive CAD in patients admitted to the CCU with acute chest pain. (Arq Bras Cardiol. 2017; [online].ahead print, PP.0-0). FUNDAMENTO:: A acurácia do escore de cálcio coronário zero como um filtro nos pacientes com dor torácica aguda tem sido demonstrada na sala de emergência e nos ambulatórios, populações com baixa prevalência de doença arterial coronariana (DAC). OBJETIVOS:: Testar o papel do escore de cálcio zero como filtro nos pacientes com dor torácica admitidos numa unidade coronariana intensiva (UCI), na qual a probabilidade pré-teste de DAC é maior do que em outras populações. MÉTODOS:: Pacientes foram submetidos a tomografia computadorizada para quantificar o escore de cálcio, DAC obstrutiva foi definida por uma estenose mínima de 70% na cineangiocoronariografia invasiva. Um escore clínico para estimar a probabilidade pré-teste de DAC obstrutiva foi criado em amostra de 370 pacientes, usado para definir subgrupos na definição de valores preditivos negativos do escore zero. RESULTADOS:: Em 146 pacientes estudados, a prevalência de DAC foi 41% e o escore de cálcio zero foi demonstrado em 35% deles. A sensibilidade e a especificidade para escore de cálcio zero resultaram numa razão de verossimilhança negativa de 0,16. Após ajuste com um escore clínico com a regressão logística para a probabilidade pré-teste, o escore de cálcio zero foi preditor independente associado a baixa probabilidade de DAC (OR = 0,12, IC95% = 0,04-0,36), aumentando a área abaixo da curva ROC do modelo clínico de 0,76 para 0,82 (p = 0,006). Considerando a probabilidade de DAC < 10% como ponto de corte para alta precoce, o escore de cálcio aumentou a proporção de pacientes para alta precoce de 8,2% para 25% (NRI = 0,20; p = 0,0018). O escore de cálcio zero apresentou valor preditivo negativo de 90%. Em pacientes com probabilidade pré-teste < 50%, o valor preditivo negativo foi 95% (IC95% = 83%-99%). CONCLUSÃO:: O escore de cálcio zero reduz substancialmente a probabilidade pré-teste de DAC obstrutiva em pacientes internados em UCI com dor torácica aguda. (Arq Bras Cardiol. 2017; [online].ahead print, PP.0-0).

Hemodynamic, catecholamine, vasomotor and vascular responses: Determinants of myocardial ischemia during mental stress.

AIMS: Mental stress-induced myocardial ischemia (MSIMI) in patients with coronary artery disease (CAD) is associated with adverse cardiovascular outcomes. We aim to assess hemodynamic, neuro-hormonal, endothelial, vasomotor and vascular predictors of MSIMI. METHODS AND RESULTS: We subjected 660 patients with stable CAD to 99mTc sestamibi myocardial perfusion imaging at rest, with mental (speech task) and with conventional (exercise/pharmacological) stress. Endothelium-dependent flow-mediated dilation (FMD), microvascular reactivity [reactive hyperemia index (RHI)] and arterial stiffness [pulse wave velocity (PWV)] were measured at rest and 30-min after mental stress. The digital microvascular vasomotor response during mental stress was assessed using peripheral arterial tonometry (PAT). A total of 106(16.1%) patients had MSIMI. Mental stress was accompanied by significant increases in rate-pressure-product (heart rate x systolic blood pressure; RPP), epinephrine levels and PWV, and significant decreases in FMD and PAT ratio denoting microvascular constriction. In comparison to those with no MSIMI, patients with MSIMI had higher hemodynamic and digital vasoconstrictive responses (p<0.05 for both), but did not differ in epinephrine, endothelial or macrovascular responses. Only presence of ischemia during conventional stress (OR of 7.1, 95%CI of 4.2, 11.9), high hemodynamic response (OR for RPP response≥vs

A Novel Timesaving Method for Hepatobiliary Imaging for Suspected Acute Cholecystitis.

OBJECTIVE: To optimize resource utilization of cholescintigraphy for suspected acute cholecystitis with a time-saving method without a loss in diagnostic accuracy. MATERIALS AND METHODS: Institutional review board approval was obtained for this retrospective study. Hepatobiliary imaging data for 81 patients with suspected acute cholecystitis were recalled for modification into 2 summed static images, using only the first and last 5 minutes of the dynamic images, thereby eliminating the middle 50 minutes of imaging data. Two nuclear medicine physicians interpreted the summed images to assess visualization, and those interpretations were compared to the original reports based on using all 60 minutes of dynamic imaging. A third nuclear medicine physician mediated rare inter-reader interpretive disagreements. Comparison of interpretations of time-saving and conventional methods and also inter-observer variability was achieved using the Cohen κ coefficient analysis. RESULTS: Interpretations rendered using the time-saving method showed near-perfect agreement with those based on the full dynamic imaging protocol (Cohen κ coefficient = 0.92 for both readers). Furthermore, nuclear medicine physician readers agreed with each other (Cohen κ coefficient = 0.95 between the 2 readers), indicating minimal inter-observer variability using this novel optimized technique. CONCLUSION: In the setting of suspected acute cholecystitis, imaging resource utilization may be improved, via reduced gamma camera and technologist time, using a novel time-saving method without sacrificing diagnostic accuracy. Multicenter larger trials, however, will be necessary to establish reproducibility.

The Mental Stress Ischemia Prognosis Study: Objectives, Study Design, and Prevalence of Inducible Ischemia.

OBJECTIVE: Mental stress-induced myocardial ischemia (MSIMI) is a common phenomenon in patients with coronary artery disease (CAD), but contemporary studies of its prognostic significance and its underlying pathophysiology are limited. METHODS: We prospectively enrolled patients with confirmed CAD in the Mental Stress Ischemia Prognosis Study (MIPS) between 2011 and 2014. All patients underwent mental stress testing using a standardized public speaking task, and ischemia was detected by Tc-sestamibi myocardial perfusion imaging. Patients also underwent conventional stress testing for myocardial ischemia (CSIMI) using exercise or pharmacological stress testing. Furthermore, digital microvascular flow, endothelial function, arterial stiffness, and blood sample collections were performed before, during, and after mental stress. Two-year adverse clinical outcomes are being assessed. RESULTS: Six-hundred ninety-five patients completed baseline enrollment in the MIPS. Their mean (standard deviation) age was 62.9 (9.1) years, 72% were men, 30% were African American, and 32% had a history myocardial infarction. The prevalence of MSIMI and CSIMI is 16.1% and 34.7%, respectively. A total of 151 patients (22.9%) had only CSIMI, 28 (4.2%) had only MSIMI, and 78 (11.8%) had both MSIMI and CSIMI. Patients with ischemia had a lower ejection fraction and higher prevalence of previous coronary artery bypass grafting compared with those without inducible ischemia (p < .050). The prevalence of obstructive CAD was not statistically different between patients with and without MSIMI (p = .426); in contrast, it was higher in patients with CSIMI (p < .001). CONCLUSIONS: The MIPS data will provide useful information to assess the prognostic significance and underlying mechanisms of MSIMI.

Sex Differences in Mental Stress-Induced Myocardial Ischemia in Patients With Coronary Heart Disease.

BACKGROUND: Emerging data suggest that young women with coronary heart disease (CHD) are disproportionally vulnerable to the adverse cardiovascular effects of psychological stress. We hypothesized that younger, but not older, women with stable CHD are more likely than their male peers to develop mental stress-induced myocardial ischemia (MSIMI). METHODS AND RESULTS: We studied 686 patients (191 women) with stable coronary heart disease (CHD). Patients underwent (99m)Tc-sestamibi myocardial perfusion imaging at rest and with both mental (speech task) and conventional (exercise/pharmacological) stress testing. We compared quantitative (by automated software) and visual parameters of inducible ischemia between women and men and assessed age as an effect modifier. Women had a more-adverse psychosocial profile than men whereas there were few differences in medical history and CHD risk factors. Both quantitative and visual indicators of ischemia with mental stress were disproportionally larger in younger women. For each 10 years of decreasing age, the total reversibility severity score with mental stress was 9.6 incremental points higher (interaction, P<0.001) and the incidence of MSIMI was 82.6% higher (interaction, P=0.004) in women than in men. Incidence of MSIMI in women ≤50 years was almost 4-fold higher than in men of similar age and older patients. These results persisted when adjusting for sociodemographic and medical risk factors, psychosocial factors, and medications. There were no significant sex differences in inducible ischemia with conventional stress. CONCLUSIONS: Young women with stable CHD are susceptible to MSIMI, which could play a role in the prognosis of this group.

Quantitative outcome of registration methods for correcting cardiac drift in cardiac PET/CT imaging.

Myocardial perfusion studies suffer from artifacts caused by misalignment of the transmission and emission data due to the influences of voluntary and involuntary patient motion. Regardless of 68Ge or respiratory-averaged CT based attenuation correction and good patient cooperation, approximately 21% of perfusion studies exhibit artifacts arising from misalignment that cannot be corrected by manipulating the attenuation acquisition protocol. This misalignment, termed cardiac drift, is caused by slow-moving abdominal cavity contents that reposition the heart in the thorax and appear as myocardial uptake overlying the left CT lung in fused PET/CT images. This study evaluates three postimaging registration techniques to correct PET/CT misalignment by altering the transmission map to match myo-cardial uptake. Simulated misalignment studies were performed with a cardiac torso phantom filled with [18F]FDG at 10:1 myocardium/background. An air-filled saline bag affixed to the medial left lung surface served as a distensible lung. An initial CT acquisition was followed by successive PET acquisitions consisting of small displacements of the cardiac insert into the left lung. Phantom transmission scans were aligned to the myocardial uptake in the emission scans by applying 1) full rigid-body translations and rotations, 2) rigid-body restricted to medial / lateral and superior / inferior translation, or 3) an emission-driven method that adds myocardial tissue to the transmission scan. These methods were also applied to 10 low-likelihood coronary artery disease (CAD) patients showing signs of cardiac drift. Full rigid-body registration showed significant over-correction (p < 0.004) of activity concentrations in the artifact areas of the phantom data due the relocation of highly attenuating structures (i.e., spine). Inaccurate regional activity distributions were also observed as streaks extending from the spine and these results were replicated in the patient population. There was no significant difference between the true phantom activity concentration after correction with the emission-driven method. Misalignment corrected with the rigid-body registration results in an increase in activity concentration but fails to accurately recover the true concentration. These data suggest that a nonlinear image registration approach such as an emission-driven method results in a more uniform activity distribution throughout the myocardium, and is more appropriate for addressing the cardiac drift misalignment problem.

The role of nuclear cardiology in the diagnosis and risk stratification of women with ischemic heart disease.

Ischemic heart disease (IHD) is the leading cause of death in women. Women present with coronary artery disease later in life than men, with greater number of risk factors and higher rate of angina. Women have higher mortality compared with age-matched men despite having less anatomical coronary artery disease. Distinct pathophysiologies are thought to account for sex-related differences in the presentation and prognosis of IHD. More women than men have chest pain secondary to coronary reactivity, microvascular dysfunction, and plaque erosion with distal microembolization. Sex-related factors such as lower exercise capacity, less specific ST-segment electrocardiographic changes, smaller left ventricular size, and breast attenuation can complicate the diagnosis of IHD in women. These sex-specific factors should be considered before determining the appropriate test to be performed in a woman with suspected IHD. Technological advances in nuclear cardiology including attenuation correction and coronary flow reserve measurement by PET hold promise in optimizing the diagnosis and risk stratification of women with IHD.

Association of vitamin D status with mental stress-induced myocardial ischemia in patients with coronary artery disease.

BACKGROUND: Mental stress-induced (MSIMI) or physical stress-induced (PSIMI) myocardial ischemia portends a worse prognosis in patients with coronary artery disease (CAD). Vitamin D insufficiency is associated with adverse cardiovascular outcomes, but its relationship to myocardial ischemia remains unclear. We hypothesized that vitamin D insufficiency will be associated with a higher prevalence of myocardial ischemia in patients with CAD. METHODS: In 255 patients with stable CAD, myocardial perfusion imaging was performed to assess ischemia in response to mental and physical stress protocols. Vitamin D insufficiency was defined as serum 25-hydroxyvitamin D [25(OH)D] levels below 30 ng/ml, collected on the day of stress testing. RESULTS: Mean (standard deviation) 25(OH)D level was 30.8 (12.8) ng/ml, and 139 (55%) patients had vitamin D insufficiency. MSIMI occurred in 30 (12%) patients and PSIMI in 67 (27%). Individuals with MSIMI had significantly lower levels of 25(OH)D as compared with those without MSIMI (24.0 [8.6] versus 31.7 [12.9], p = .002). The prevalence of MSIMI was higher in those with as compared with those without vitamin D insufficiency (17% versus 6%, p = .009). Moreover, low 25(OH)D levels remained independently associated with MSIMI after adjusting for potential confounders. Conversely, 25(OH)D levels were similar between those with or without PSIMI (29.8 [13.0] versus 31.4 [12.7], p = .37), as was the prevalence of PSIMI in those with or without vitamin D insufficiency (29% versus 24%, p = .42). CONCLUSIONS: Vitamin D insufficiency is associated with a higher prevalence of MSIMI but not PSIMI among stable patients with CAD. Whether this association serves as a potential mechanism linking low vitamin D status to adverse cardiovascular outcomes warrants further investigation.

Diagnostic performance of low-dose rest/stress Tc-99m tetrofosmin myocardial perfusion SPECT using the 530c CZT camera: quantitative vs visual analysis.

BACKGROUND: We set out to develop normal databases and prospectively validate abnormality criteria for a low-dose Tc-99m tetrofosmin myocardial perfusion SPECT protocol using the 530c CZT camera. METHODS: All patients received 6 mCi rest/20 mCi stress doses of Tc-99m tetrofosmin. Rest and stress images were obtained over 7-9 and 5-7 minutes according to the chest size. Low-dose CT of the chest was obtained on a standalone CT scanner. Forty patients with very low likelihood (LLK) of coronary artery disease (CAD) were used to define the normal count distributions. The abnormality criteria were prospectively validated in 55 patients who had coronary angiography and in 40 patients with LLK of CAD. RESULTS: The results for quantitative non-attenuation-corrected (AC) and AC analysis and visual analysis were as follows: sensitivity of 79%, 85%, and 92% (P = NS) and specificity of 44%, 75%, and 56% (P = NS), respectively. The normalcy rates for quantitative non-AC and AC analyses and visual analysis were 95%, 98%, and 98% (P = NS). CONCLUSIONS: We have developed non-AC and AC normal databases for low-dose rest/stress Tc-99m tetrofosmin myocardial perfusion SPECT protocol using the 530c CZT camera. The per-patient diagnostic performance of quantitative analyses is not significantly different from visual analysis by an experienced reader.

Myocardial ischemia during mental stress: role of coronary artery disease burden and vasomotion.

BACKGROUND: Mental stress-induced myocardial ischemia (MSIMI) is associated with adverse prognosis in patients with coronary artery disease (CAD), yet the mechanisms underlying this phenomenon remain unclear. We hypothesized that compared with exercise/pharmacological stress-induced myocardial ischemia (PSIMI) that is secondary to the atherosclerotic burden of CAD, MSIMI is primarily due to vasomotor changes. METHODS AND RESULTS: Patients with angiographically documented CAD underwent 99mTc-sestamibi myocardial perfusion imaging at rest and following both mental and physical stress testing, performed on separate days. The severity and extent of CAD were quantified using the Gensini and Sullivan scores. Peripheral arterial tonometry (Itamar Inc) was used to assess the digital microvascular tone during mental stress as a ratio of pulse wave amplitude during speech compared with baseline. Measurements were made in a discovery sample (n = 225) and verified in a replication sample (n = 159). In the pooled (n = 384) sample, CAD severity and extent scores were not significantly different between those with and without MSIMI, whereas they were greater in those with compared with those without PSIMI (P < 0.04 for all). The peripheral arterial tonometry ratio was lower in those with compared with those without MSIMI (0.55 ± 0.36 versus 0.76 ± 0.52, P = 0.009). In a multivariable analysis, the peripheral arterial tonometry ratio was the only independent predictor of MSIMI (P = 0.009), whereas angiographic severity and extent of CAD independently predicted PSIMI. CONCLUSIONS: The degree of digital microvascular constriction, and not the angiographic burden of CAD, is associated with MSIMI. Varying causes of MSIMI compared with PSIMI may require different therapeutic interventions that require further study.