Myocardial Perfusion Imaging For Detection Research Articles

Abstract 16882: Comparison of Regadenoson and Adenosine in First Pass Quantitative Perfusion Cardiovascular Magnetic Resonance in Subjects With Suspected Coronary Microvascular Disease

Introduction: Regadenoson and adenosine are commonly used vasodilators in myocardial perfusion imaging for detection of coronary artery disease. There are no comparative studies of the vasodilator properties of two agents in subjects with suspected coronary microvascular disease (CMD). We aimed to compare the potency of two vasodilators by quantifying myocardial perfusion in subjects with suspected CMD. Methods: Subjects with angina and more than two risk factors for CMD (females, or males with diabetes, metabolic syndrome, HTN, hyperlipidemia, and smoking) who had no obstructive coronary disease by invasive coronary angiography or CT angiography were enrolled for first-pass perfusion images using dual sequence. Stress perfusion images were acquired on 1.5T or 3.0T GE Healthcare during adenosine infusion or regadenoson. Rest perfusion images were acquired either 10 minutes following the cessation of adenosine or reversal with aminophylline. Myocardial blood flow (MBF) in ml/min/g and myocardial perfusion reserve (MPR) were quantified using Fermi deconvolution. Results: A total of thirty-two subjects were recruited with a mean age of 62±11 years, 53% men, history of hypertension in 91%, diabetes in 72%, hyperlipidemia in 75%, and tobacco use in 16%. Twenty (63%) of subjects underwent adenosine, while twelve (38%) of subjects underwent regadenoson. Regadenoson produced similar stress MBF compared to adenosine (2.30 ± 0.54 vs. 2.35 ± 0.61 ml/min/g, p = 0.66). Rest MBF was higher in the regadenoson group compared to adenosine group (1.35±0.35 vs. 1.12±0.26 ml/min/g, p=0.07). MPR was non-significantly lower in regadenoson compared to adenosine 1.72±0.70 vs.1.89±0.53 ml/g/min, p=0.13). Conclusions: Based on fully quantitative perfusion using CMR, regadenoson and adenosine have similar vasodilator efficacy in subjects with risk factors for CMD. However, resting blood flows are slightly higher when regadenoson is used which may impact quantification of MPR.

Editorial Comment: The Role of Artificial Intelligence-Guided Coronary CTA Interpretation in Coronary Artery Disease Management With Comparison With Myocardial Perfusion Imaging.

This Editorial Comment discusses the following AJR article: Coronary CTA With AI-QCT Interpretation: Comparison With Myocardial Perfusion Imaging for Detection of Obstructive Stenosis UsingInvasive Angiography as Reference Standard.

Non-invasive CT-derived fractional flow reserve and static rest and stress CT myocardial perfusion imaging for detection of haemodynamically significant coronary stenosis

Computed tomography derived fractional flow reserve (FFRCT) and computed tomography stress myocardial perfusion imaging (CTP) are techniques to assess haemodynamic significance of coronary stenosis. To compare the diagnostic performance of FFRCT and static rest/stress CTP in detecting fractional flow reserve (FFR) defined haemodynamically-significant stenosis (FFR ≤ 0.8). Fifty-one patients (96 vessels) with suspected coronary artery disease from a single institution planned for elective invasive-angiography prospectively underwent research indicated 320-detector-CT-coronary-angiography (CTA) and adenosine-stress CTP and invasive FFR. Analyses were performed in separate core-laboratories for FFRCT and CTP blinded to FFR results. Myocardial perfusion was assessed visually and semi-quantitatively by transmural perfusion ratio (TPR). Invasive FFR ≤ 0.8 was present in 33% of vessels and 49% of patients. FFRCT, visual CTP and TPR analysis was feasible in 96%, 92% and 92% of patients respectively. Overall per-vessel sensitivity, specificity and diagnostic accuracy for FFRCT were 81%, 85%, 84%, for visual CTP were 50%, 89%, 75% and for TPR were 69%, 48%, 56% respectively. Receiver-operating-characteristics curve analysis demonstrated larger per vessel area-under-curve (AUC) for FFRCT (0.89) compared with visual CTP (0.70; p < 0.001), TPR (0.58; p < 0.001) and CTA (0.70; p = 0.0007); AUC for CTA + FFRCT (0.91) was higher than CTA + visual CTP (0.77, p = 0.008) and CTA + TPR (0.74, p < 0.001). Per-patient AUC for FFRCT (0.90) was higher than visual CTP (0.69; p = 0.0016), TPR (0.56; p < 0.0001) and CTA (0.68; p = 0.001). Based on this selected cohort of patients FFRCT is superior to visually and semi-quantitatively assessed static rest/stress CTP in detecting haemodynamically-significant coronary stenosis as determined on invasive FFR.

P2394Diagnostic performance of CT derived fractional flow reserve using reduced order modelling and CT stress myocardial perfusion imaging for detection of haemodynamically significant coronary stenosis

P2394Diagnostic performance of CT derived fractional flow reserve using reduced order modelling and CT stress myocardial perfusion imaging for detection of haemodynamically significant coronary stenosis

Diagnostic accuracy of coronary CT angiography combined with dual-energy myocardial perfusion imaging for detection of myocardial infarction.

The aim of the present study was to evaluate the diagnostic accuracy of second generation dual-energy computed tomography (DECT) myocardial perfusion imaging for the detection of myocardial infarction (MI) in patients with suspected MI. In total, 56 patients underwent DECT. Among those, 40 patients had MI that was detected by catheter coronary angiography and cardiac troponin I elevation and evolution of acute MI detected by electrocardiogram changes. The diagnostic accuracy, including the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for the detection of MI were evaluated, as well as the coronary image quality of coronary artery and radiation dose. The sensitivity, specificity, PPV and NPV for the detection of MI were 95.0, 97.0, 86.4 and 98.9%, respectively. Moreover, the image quality was rated excellent (score 1) in 90.2% (515/571), good (score 2) in 6.5% (37/571), adequate (score 3) in 1.9% (11/571) and non-diagnostic (score 4) in 1.4% (8/571) of the coronary segments. The effective radiation dose was on average 6.1±1.5 mSv (3.1–10.9 mSv). Therefore, combined DE iodine maps and coronary CT angiography using the DECT may provide a high diagnostic accuracy for detecting MI with lower radiation exposure in patients with suspected MI.

Prognostic implications of myocardial perfusion imaging and coronary calcium score in a Macedonian cohort of asymptomatic patients with type 2 diabetes.

Type 2 diabetes is a risk factor for coronary artery disease; however, a number of studies have shown that patients are asymptomatic for coronary artery disease. The presence of coronary artery disease in asymptomatic patients with type 2 diabetes was evaluated to determine its impact on management decision and prognosis. A total of 75 patients underwent single-photon emission computed tomography myocardial perfusion imaging for detection of suspected coronary artery disease. We used 17-segment model for perfusion and function analysis. Multislice computed tomography was performed in 45 patients to assess coronary artery calcium. Complete laboratory analyses with lipid values and standard risk factors were analysed. Forward logistic regression analysis was used to assess predictive parameters for myocardial ischaemia during the follow-up period of 20 ± 4 months. Silent myocardial ischaemia and subclinical coronary artery disease can be detected in a significant proportion of asymptomatic patients with type 2 diabetes. Diabetic patients with normal myocardial perfusion imaging had an excellent 2-year prognosis with optimal medical therapy and intensive risk factor control. In comparison, an abnormal myocardial perfusion imaging led to an increased risk of cardiovascular events. Myocardial perfusion imaging and coronary artery calcium are valuable tools for risk stratification and optimal treatment decision in this asymptomatic diabetic cohort of Macedonian patients.

Diagnostic Performance of CT-Derived Fractional Flow Reserve using Three Dimensional Fluid Modelling and CT Stress Myocardial Perfusion Imaging for Detection of Haemodynamically Significant Coronary Stenosis

Diagnostic Performance of CT-Derived Fractional Flow Reserve using Three Dimensional Fluid Modelling and CT Stress Myocardial Perfusion Imaging for Detection of Haemodynamically Significant Coronary Stenosis

Diagnostic Performance of CT Derived Fractional Flow Reserve Using Reduced Order Modelling and CT Stress Myocardial Perfusion Imaging for Detection of Haemodynamically Significant Coronary Stenosis

Diagnostic Performance of CT Derived Fractional Flow Reserve Using Reduced Order Modelling and CT Stress Myocardial Perfusion Imaging for Detection of Haemodynamically Significant Coronary Stenosis

Diagnostic value of transmural perfusion ratio derived from dynamic CT-based myocardial perfusion imaging for the detection of haemodynamically relevant coronary artery stenosis

ObjectivesTo investigate the additional value of transmural perfusion ratio (TPR) in dynamic CT myocardial perfusion imaging for detection of haemodynamically significant coronary artery disease compared with fractional flow reserve (FFR).MethodsSubjects with suspected or known coronary artery disease were prospectively included and underwent a CT-MPI examination. From the CT-MPI time-point data absolute myocardial blood flow (MBF) values were temporally resolved using a hybrid deconvolution model. An absolute MBF value was measured in the suspected perfusion defect. TPR was defined as the ratio between the subendocardial and subepicardial MBF. TPR and MBF results were compared with invasive FFR using a threshold of 0.80.ResultsForty-three patients and 94 territories were analysed. The area under the receiver operator curve was larger for MBF (0.78) compared with TPR (0.65, P = 0.026). No significant differences were found in diagnostic classification between MBF and TPR with a territory-based accuracy of 77 % (67-86 %) for MBF compared with 70 % (60-81 %) for TPR. Combined MBF and TPR classification did not improve the diagnostic classification.ConclusionsDynamic CT-MPI-based transmural perfusion ratio predicts haemodynamically significant coronary artery disease. However, diagnostic performance of dynamic CT-MPI-derived TPR is inferior to quantified MBF and has limited incremental value.Key Points• The transmural perfusion ratio from dynamic CT-MPI predicts functional obstructive coronary artery disease• Performance of the transmural perfusion ratio is inferior to quantified myocardial blood flow• The incremental value of the transmural perfusion ratio is limited

Combined Quantitative Assessment of Myocardial Perfusion and Coronary Artery Calcium Score by Hybrid 82Rb PET/CT Improves Detection of Coronary Artery Disease.

Hybrid PET myocardial perfusion imaging (MPI) with CT allows the incorporation of coronary artery calcium (CAC) into the clinical protocol. We aimed to determine whether the combined analysis of MPI and CAC could improve the diagnostic accuracy of PET MPI in detection of obstructive coronary artery disease (CAD). Consecutive patients (n = 152; mean age ± SD, 69 ± 12 y) without prior CAD, referred to (82)Rb PET MPI followed by invasive coronary angiography performed within 14 days, were studied. Myocardial perfusion was quantified automatically for left anterior descending, left circumflex, and right coronary artery territories as an ischemic total perfusion deficit (ITPD) for 456 vessels. Global and per-vessel CAC Agatston scores were calculated. Obstructive CAD was defined as 50% or greater stenosis of the left main and 70% or greater stenosis in the left anterior descending, left circumflex, and right coronary arteries. Logistic regression and 10-fold cross validation were used to derive and validate the combined ITPD/logCAC (logarithm of coronary calcium) scores. In the prediction of per-vessel obstructive CAD, the receiver-operating-characteristic area under the curve for combined per-vessel ITPD/logCAC score was higher, 0.85 (95% confidence interval [CI], 0.81-0.89), than standalone ITPD area under the curve, 0.81 (95% CI: 0.76-0.85), and logCAC score, 0.73 (95% CI, 0.68-0.78; P < 0.05). The integrated discrimination improvement of combined per-vessel ITPD/logCAC analysis was 0.07 (95% CI, 0.04-0.09; P < 0.0001), as compared with ITPD alone. Combined automatically derived per-vessel ITPD and logCAC score improves accuracy of (82)Rb PET MPI for detection of obstructive CAD.

A primer on the methods and applications for contrast echocardiography in clinical imaging.

Contrast echocardiography is broadly described as a variety of techniques whereby the blood pool on cardiac ultrasound is enhanced with encapsulated gas-filled microbubbles or other acoustically active nano- or microparticles. The development of this technology has occurred primarily in response to the need improve current diagnostic applications of echocardiography such as the need to better define left ventricular cavity volumes, regional wall motion, or the presence or absence of masses and thrombi. A secondary reason for the development of contrast echocardiography has been to expand the capabilities of echocardiography. These new applications include myocardial perfusion imaging for detection of ischemia and viability, perfusion imaging of masses/tumors, and molecular imaging. The ability to fill all of these current and future clinical roles has been predicated on the ability to produce robust contrast signal which, in turn, has relied on technical innovation with regards to the microbubble contrast agents and the ultrasound imaging paradigms. In this review, we will discuss the basics of contrast echocardiography including the composition of microbubble contrast agents, the unique imaging methods used to optimize contrast signal-to-noise ratio, and the clinical applications of contrast echocardiography that have made a clinical impact.

Additional applications of approved radiopharmaceuticals for nuclear cardiology

Radionuclide studies of the heart and blood vessels provide information for patient management as well as an understanding of patient-specific pathophysiology. The information gleaned from these studies may be enhanced by using more than a single tracer or by making multiple measurements with a single radiopharmaceutical (similar to measuring thallium redistribution). After more than 40 years of clinical use (Valenta et al., Curr Cardiol Rep 15:344, 2013), the examination with the most clinical value continues to be myocardial perfusion imaging for detection of myocardial ischemia and scar. New techniques, however, are available to expand the application of approved radiopharmaceuticals in patients with heart disease. This manuscript will present recent developments in two areas: (1) Evaluation of mitochondrial function or sympathetic innervation in patients with heart failure (HF). In this case, radionuclide techniques provide data that adds significant predictive value to functional parameters, such as left ventricular ejection fraction, to identify HF patients at high risk of clinical events. (2) Direct evaluation of focal vascular inflammation, microcalcification and calcification in patients with dyslipidemia. Localization and characterization of the intensity of inflammation, or early phases of calcification in atheroma, may permit more personalized therapy than can be obtained from traditional measurements of lipid levels in patients with dyslipidemia. Ultimately, characterizing atheroma, especially in the coronary and carotid arteries, may be the imaging approach of choice to permit effective pharmacologic therapy geared at reducing the incidence and severity of clinical events.

Letter regarding Bettencourt et al. “Cardiac magnetic resonance myocardial perfusion imaging for detection of functionally significant obstructive coronary artery disease: A prospective study”

Letter regarding Bettencourt et al. “Cardiac magnetic resonance myocardial perfusion imaging for detection of functionally significant obstructive coronary artery disease: A prospective study”

Phase II Safety and Clinical Comparison With Single-Photon Emission Computed Tomography Myocardial Perfusion Imaging for Detection of Coronary Artery Disease

This was a phase II trial to assess flurpiridaz F 18 for safety and compare its diagnostic performance for positron emission tomography (PET) myocardial perfusion imaging (MPI) with Tc-99m single-photon emission computed tomography (SPECT) MPI with regard to image quality, interpretative certainty, defect magnitude, and detection of coronary artery disease (CAD) (≥50% stenosis) on invasive coronary angiography (ICA).In pre-clinical and phase I studies, flurpiridaz F 18 has shown characteristics of an essentially ideal MPI tracer.One hundred forty-three patients from 21 centers underwent rest-stress PET and Tc-99m SPECT MPI. Eighty-six patients underwent ICA, and 39 had low-likelihood of CAD. Images were scored by 3 independent, blinded readers.A higher percentage of images were rated as excellent/good on PET versus SPECT on stress (99.2% vs. 88.5%, p < 0.01) and rest (96.9% vs. 66.4, p < 0.01) images. Diagnostic certainty of interpretation (percentage of cases with definitely abnormal/normal interpretation) was higher for PET versus SPECT (90.8% vs. 70.9%, p < 0.01). In 86 patients who underwent ICA, sensitivity of PET was higher than SPECT (78.8% vs. 61.5%, respectively, p = 0.02). Specificity was not significantly different (PET: 76.5% vs. SPECT: 73.5%). Receiver-operating characteristic curve area was 0.82 ± 0.05 for PET and 0.70 ± 0.06 for SPECT (p = 0.04). Normalcy rate was 89.7% with PET and 97.4% with SPECT (p = NS). In patients with CAD on ICA, the magnitude of reversible defects was greater with PET than SPECT (p = 0.008). Extensive safety assessment revealed that flurpiridaz F 18 was safe in this cohort.In this phase 2 trial, PET MPI with flurpiridaz F 18 was safe and superior to SPECT MPI for image quality, interpretative certainty, and overall CAD diagnosis.

Accuracy of low-dose rubidium-82 myocardial perfusion imaging for detection of coronary artery disease using 3D PET and normal database interpretation

BackgroundOur aim was to develop a normal database to be used for quantification of myocardial perfusion and diagnosis of “obstructive coronary artery disease” (CAD) using low-dose rubidium-82 three-dimensional (3D) positron emission tomography (PET)-CT. MethodsFrom a record of 1,501 patients, 77 were identified as having low-likelihood (LLK) of CAD. Forty LLK patients were used to construct a normal database using 4DM-PET, the remainder used for validation of normalcy. A group of 70 patients with CAD who had invasive coronary angiography and PET-CT were used to evaluate the accuracy of the database for detecting CAD using the sum-stress-score. The effect of clinical exclusion criteria and the inclusion of LLK patients were evaluated. ResultsThe normal database for CAD detection had a normalcy rate of 95%. Sensitivity was 100% for detecting patients with either 50% or 70% stenosis. Optimal specificity was 87% for either 50% or 70% stenosis. For localizing disease at 50% stenosis in the left anterior descending, left circumflex, and right coronary artery, sensitivity ranged from 59% to 68%, while specificity was maintained at 87-89%. Similarly, at 70% stenosis, sensitivity ranged from 64% to 79%, and specificity from 87% to 91%. ConclusionsA normal database containing the relative perfusion scores of patients with LLK of CAD can be used to accurately diagnose obstructive coronary disease using low-dose Rb-82 with 3D PET-CT imaging.

Cardiac magnetic resonance myocardial perfusion imaging for detection of functionally significant obstructive coronary artery disease: A prospective study

BackgroundCardiac magnetic resonance myocardial perfusion imaging (CMR-MPI) is considered a state of the art non-invasive modality for the detection of reversible ischemia. Recent studies have shown its utility in the diagnosis of coronary artery disease (CAD) and superiority over other established techniques. However, only a few studies compared CMR-MPI against the invasive standard including fractional flow reserve (FFR) and clinical validation in non-specialized centers is scarce. The aim of this study was to validate CMR-MPI in a real-world clinical environment and to test its diagnostic accuracy in symptomatic patients with suspected CAD versus FFR as the reference standard of functionally significant disease. Methods and results103 symptomatic consecutive patients (62±8.0years, 66% males) with suspected CAD and intermediate or high probability of disease underwent sequential CMR and invasive coronary angiography (XA). The CMR protocol included stress-rest adenosine perfusion, SSFP cine imaging and late-enhancement imaging. Functionally significant CAD was defined as occlusive/sub-occlusive stenoses on XA or non-occlusive stenoses with a FFR measurement of <0.80 in vessels >2mm. On a patient-based model, CMR-MPI had sensitivity, specificity, positive and negative predictive values of 89%, 88%, 85%, and 91%, respectively, with a global accuracy of 88%. On a vessel-based analysis, these values were 80%, 93%, 79% and 94%, respectively, with a global accuracy of 90%. ConclusionsCMR-MPI had a very high accuracy for detection of functionally significant CAD as assessed by FFR in patients with intermediate to high pretest probability.

Detection of myocardial infarction with dual energy CT myocardial iodine maps and perfusion myocardial single photon emission computed tomography scintigraphy: an experimental study in canine

Objective To investigate the feasibility and accuracy of dual energy CT myocardial iodine maps in detecting acute myocardial infarction in canine model. Methods Myocardial ischemia model was made by ligaturing left anterior descending coronary arteries (LAD) after thoracotomy in six dogs, while another 3 dogs undergoing thoracotomy not ligaturing LAD as control group. Before and three hours after operation, dual-source CT (DSCT) was performed, followed by resting 99Tcm-MIBI single photon emission computed tomography myocardial perfusion imaging. Then, dogs were sacrificed, and the hearts were removed, triphenyltetrazolium chloride staining and conventional HE staining were performed. CT number of non-ischemic and ischemic regions were measured and analyzed. The wall of the left ventricle in the short axis was divided into 17 segments, the segments of myocardial perfusion defect in DSCT myocardial iodine maps, SPECT, and pathology were determined. Student t test was used to analyze the difference of CT number between infarcted and non-infarcted myocardium. Kappa test was used for the accuracy of DSCT myocardial iodine maps and SPECT in detecting myocardial ischemia according to the pathological results. Results No abnormal regions were detected using DSCT myocardial iodine maps in preoperative control and infarction group. After thoracotomy, partial sparse or defective perfusion was consistently noted in six dogs' apical anterior and partition wall in both DSCT myocardial iodine maps and SPECT. In the infarcted group, the attenuation of infarction region (34.75 ± 16.66) HU was significantly decreased compared with preoperative measurements ( 123. 18 ± 15.38 ) HU ( t = 10. 526, P ＜ 0. 01 ); decreased perfusion in the infarcted region was also noted in the DSCT myocardial iodine maps and SPECT. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of DSCT myocardial iodine maps and SPECT were 85.0% (34/40) , 84. 1% (95/113) ,65.4% (34/52) ,94. 0%(95/101) ,and 82. 5% (33/40), 90. 3% ( 102/113 ) ,75.0% (33/44) ,93.6% ( 102/109 ), respectively.Kappa values were 0. 63 and 0. 71 for the agreement of DSCT myocardial iodine maps and SPECT.Conclusion DSCT myocardial iodine maps is comparable diagnostic accuracy with rest SPECT myocardial perfusion imaging in detection of acute myocardial infarction in a canine model. Key words: Myocardial infarction; Tomography, X-ray computed; Perfusion; Tomography,emission-computed, single-photon

Quantitative Upright–Supine High-Speed SPECT Myocardial Perfusion Imaging for Detection of Coronary Artery Disease: Correlation with Invasive Coronary Angiography

A recently developed camera system for high-speed SPECT (HS-SPECT) myocardial perfusion imaging shows excellent correlation with conventional SPECT. Our goal was to test the diagnostic accuracy of an automated quantification of combined upright and supine myocardial SPECT for detection of coronary artery disease (CAD) (≥ 70% luminal diameter stenosis or, in left main coronary artery, ≥ 50% luminal diameter stenosis) in comparison to invasive coronary angiography (ICA). We studied 142 patients undergoing upright and supine HS-SPECT, including 56 consecutive patients (63% men; mean age ± SD, 64 ± 13 y; 45% exercise stress) without known CAD who underwent diagnostic ICA within 6 mo of HS-SPECT and 86 consecutive patients with a low likelihood of CAD. Reference limits for upright and supine HS-SPECT were created from studies of patients with a low likelihood of CAD. Automated software adopted from supine-prone analysis was used to quantify the severity and extent of perfusion abnormality and was expressed as total perfusion deficit (TPD). TPD was obtained for upright (U-TPD), supine (S-TPD), and combined upright-supine acquisitions (C-TPD). Stress U-TPD ≥ 5%, S-TPD ≥ 5%, and C-TPD ≥ 3% myocardium were considered abnormal for per-patient analysis, and U-TPD, S-TPD, and C-TPD ≥ 2% in each coronary artery territory were considered abnormal for per-vessel analysis. On a per-patient basis, the sensitivity was 91%, 88%, and 94% for U-TPD, S-TPD, and C-TPD, respectively, and specificity was 59%, 73%, and 86% for U-TPD, S-TPD, and C-TPD, respectively. C-TPD had a larger area under the receiver-operating-characteristic curve than U-TPD or S-TPD for identification of stenosis ≥ 70% (0.94 vs. 0.88 and 0.89, P < 0.05 and not significant, respectively). On a per-vessel basis, the sensitivity was 67%, 66%, and 69% for U-TPD, S-TPD, and C-TPD, respectively, and specificity was 91%, 94%, and 97% for U-TPD, S-TPD, and C-TPD, respectively (P = 0.02 for specificity U-TPD vs. C-TPD). In this first comparison of HS-SPECT with ICA, new automated quantification of combined upright and supine HS-SPECT shows high diagnostic accuracy for detecting clinically significant CAD, with findings comparable to those reported using conventional SPECT.

Comparison of dual to single contrast bolus magnetic resonance myocardial perfusion imaging for detection of significant coronary artery disease

To investigate the incremental diagnostic value of dual-bolus over single-contrast-bolus first pass magnetic resonance myocardial perfusion imaging (MR-MPI) for detection of significant coronary artery disease (CAD). Patients (n = 49) with suspected CAD underwent first pass adenosine stress and rest MR-MPI and invasive coronary angiography (CA). Gadolinium diethylenetriamine pentaacetic acid (Gd-DTPA) was injected with a prebolus (1 mL) and a large bolus (0.1 mmol/kg). For the single-bolus technique, the arterial input function (AIF) was obtained from the large-contrast bolus. For the dual-bolus technique, the AIF was reconstructed from the prebolus. Absolute myocardial perfusion was calculated by Fermi-model constrained deconvolution. Receiver operating characteristic (ROC) analysis was used to investigate diagnostic accuracy of MR myocardial perfusion imaging for detection of significant CAD on CA at vessel-based analysis. The area under the curve (AUC) of the minimal stress perfusion value for the detection of significant CAD using the single-bolus and dual-bolus technique was 0.85 +/- 0.04 (95% confidence interval [CI], 0.77-0.93) and 0.77 +/- 0.05 (95% CI, 0.67-0.86), respectively. In this study the dual-bolus technique had no incremental diagnostic value over single-bolus technique for detection of significant CAD with the used contrast concentrations.

Integrated assessment of coronary anatomy and myocardial perfusion using a retractable SPECT camera combined with 64-slice CT: initial experience

We evaluated a prototype SPECT system integrated with multidetector row CT (MDCT) for obtaining complementary information on coronary anatomy and hemodynamic lesion significance. Twenty-five consecutive patients with known or suspected coronary artery disease (CAD) underwent routine SPECT myocardial perfusion imaging (MPI). All patients also underwent repeat MPI with a mobile SPECT unit which could be attached to a 64-slice MDCT system. Coronary CT angiography (cCTA) was performed without repositioning the patient. Investigational MPI was compared with routine MPI for detection of myocardial perfusion defects (PD). Two observers diagnosed presence or absence of CAD based on MPI alone, cCTA alone, and based on combined MPI and cCTA with fused image display. In 22/24 patients investigative MPI corresponded with routine MPI (r = 0.80). Stenosis >or= 50% at cCTA was detected in 6/24 patients. Six out of 24 patients had PD at regular MPI. Three of these six patients had no significant stenosis at cCTA. Three out of 19 patients with normal MPI studies had significant stenosis at cCTA. Our initial experience indicates that the integration of SPECT MPI with cCTA is technically feasible and enables the comprehensive evaluation of coronary artery anatomy and myocardial perfusion with a single instrumental setup.