Work-up Of Coronary Artery Disease Research Articles

Photon counting computed tomography of in-stent-stenosis in a phantom: Optimal virtual monoenergetic imaging in ultra high resolution

Coronary computed tomography angiography (CCTA) is becoming increasingly important for the diagnostic workup of coronary artery disease, nevertheless, imaging of in-stent stenosis remains challenging. For the first time, spectral imaging in Ultra High Resolution (UHR) is now possible in clinically available photon counting CT. The aim of this work is to determine the optimal virtual monoenergetic image (VMI) for imaging in-stent stenoses in cardiac stents. 6 stents with inserted hypodense stenoses were scanned in an established phantom in UHR mode. Images were reconstructed with 3 different kernels for spectral data (Qr56, Qr64, Qr72) with varying levels of sharpness. Based on region of interest (ROI) measurements image quality parameters including contrast-to-noise ratio (CNR) were analyzed for all available VMI (40keV-190keV). Finally, based on quantitative results and VMI used in clinical routine, a set of VMI was included in a qualitative reading. CNR showed significant variations across different keV levels (p<0.001). Due to reduced noise there was a focal maximum in the VMI around 65keV. The peak values were observed for kernel Qr56 at 116keV with 19.47±8.67, for kernel Qr64 at 114keV with 13.56±6.58, and for kernel Qr72 at 106keV with 12.19±3.25. However, in the qualitative evaluation the VMI with lower keV (55keV) performed best. Based on these experimental results, a photon counting CCTA in UHR with stents should be reconstructed with the Qr72 kernel for the assessment of in-stent stenoses, and a VMI 55keV should be computed for the evaluation.

The time-dependent prognostic value of coronary computed tomography angiography in symptomatic patients

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): State Research Funding for Turku University Hospital. Background Coronary computed tomography angiography (CCTA) is recommended for diagnostic workup of coronary artery disease (CAD) and is known to provide prognostic information. However, it is unknown whether there is time-dependent variation in the prognostic strength of CCTA. Purpose To study the time-varying prognostic value of CCTA in patients with suspected CAD. Methods From two academic medical centers, we identified symptomatic patients who underwent CCTA for suspected CAD. A composite endpoint of all-cause mortality and myocardial infarction was recorded. The prognostic value of non-obstructive or obstructive (≥50%) CAD was assessed by Cox proportional hazard model. The prognostic power of the model according to the cumulative length of follow-up was evaluated by measuring area under the receiver operating characteristic (ROC) curve (AUC) as a function of follow-up time (time-dependent AUC). Results A total of 2662 patients (age 61 ± 10 years, 45% male) were included, with 247 adverse events (9%) during a median follow-up time of 6.9 years (25th–75th percentile 4.9–8.8 years; maximum 13.3 years). Based on CCTA, 804 (30%) patients had no CAD, 963 (36%) had non-obstructive CAD, and 895 (34%) had obstructive CAD. The presence of non-obstructive CAD (adjusted HR 2.24; p = 0.002) or obstructive CAD (adjusted HR 4.42; p&amp;lt;0.001) were independent predictors of adverse outcome. The predictive power of CCTA findings was relatively stable until 10 years of follow-up time, as demonstrated in the Figure showing time-dependent AUC of the adjusted model (solid line) with 95% confidence intervals (dashed lines). A model including only clinical variables is shown for comparison. Conclusion Coronary CTA findings retain their prognostic value in at least 10-year follow-up of symptomatic patients evaluated for suspected CAD.

Radiomics in Cardiac Computed Tomography.

In recent years, there has been an increasing recognition of coronary computed tomographic angiography (CCTA) and gated non-contrast cardiac CT in the workup of coronary artery disease in patients with low and intermediate pretest probability, through the readjustment guidelines by medical societies. However, in routine clinical practice, these CT data sets are usually evaluated dominantly regarding relevant coronary artery stenosis and calcification. The implementation of radiomics analysis, which provides visually elusive quantitative information from digital images, has the potential to open a new era for cardiac CT that goes far beyond mere stenosis or calcification grade estimation. This review offers an overview of the results obtained from radiomics analyses in cardiac CT, including the evaluation of coronary plaques, pericoronary adipose tissue, and the myocardium itself. It also highlights the advantages and disadvantages of use in routine clinical practice.

Transient left bundle branch block associated with very high coronary artery calcium: a case report.

Coronary artery calcium (CAC) is the measure of subclinical coronary artery atherosclerosis most strongly associated with atherosclerotic cardiovascular disease (ASCVD) risk. However, CAC is rarely reported in the inpatient setting to guide chest pain management. We present a case of very high CAC in a 64-year-old woman with hypertension, type 2 diabetes, and hyperlipidemia presenting with dyspnea. Initial electrocardiogram (ECG) demonstrated normal conduction with a heart rate of 76 beats/min, but new T-wave inversions in V1-V4 and a high-sensitivity troponin-I (hsTnI) value of 6 ng/L (normal < 6 ng/L). Repeat ECG in the emergency department showed normal sinus rhythm (heart rate of 80 beats/min); however, it subsequently demonstrated a left bundle branch block (LBBB) with a repeat hsTnI of 7 ng/L. Stress testing with pharmacologic single-photon emission computerized tomography did not show scintigraphic evidence of ischemia but noted extensive CAC and a concern for balanced ischemia. Subsequent coronary computed tomography angiography (CCTA) showed nonobstructive disease and a total Agatston CAC score of 1262. Invasive evaluation with left heart catheterization was deferred given the patient's unchanged symptoms and CCTA findings. Statin therapy was intensified and aspirin, metoprolol succinate, and antihypertension therapies were continued. Initiation of glucose-lowering therapy and lipoprotein(a) testing was strongly recommended on follow-up. Our case suggests that CAC ⩾ 1000 may be incidentally associated with transient LBBB during the workup of coronary artery disease. Here, we specifically show that functional testing that incorporates measurement of CAC burden can help to improve ASCVD-preventive pharmacotherapy initiation and intensification beyond the identification of obstructive disease alone.

Relationship between the neutrophil to HDL-C ratio and anatomical significance of coronary artery stenosis in patients with documented myocardial ischemia.

Diagnostic workup of coronary artery disease (CAD) requires a stepwise approach, starting with detailed history-taking and ending with invasive coronary angiography (ICA) in some cases. The neutrophil to high-density lipoprotein cholesterol (HDL-C) ratio (NHR) is related to CAD. We assessed the association between the NHR and anatomical significance of coronary artery stenosis (CAS) in patients with documented ischemia. The study enrolled 306 consecutive patients with documented myocardial ischemia on myocardial perfusion imaging (MPI). All patients underwent ICA. Patients with no visible stenosis (NVS) or minimal or mild CAS were compared with those with moderate or severe CAS. The study compared 85 patients with NVS or minimal or mild CAS (46.51% female) and 221 patients with moderate or severe CAS (31.58% female). In the latter group, hypertension and diabetes mellitus (DM) were more prevalent than in the former group (83.73% vs. 60.47%, p<0.001; 47.37% vs. 30.23%, p=0.005, respectively). A higher NHR (cut-off point of 103.2) was associated with moderate or severe CAS. Even when myocardial ischemia is demonstrated by MPI, NVS or minimal or mild CAS is still frequently diagnosed based on ICA. A lower NHR could be an inexpensive, non-invasive marker of the need for ICA.

Quantitative plaque assessment by coronary computed tomography angiography: An up-to-date review

Abstract Coronary computed tomography angiography has an emerging role in the diagnostic workup of coronary artery disease. Due to its high sensitivity and negative predictive value, coronary computed tomography angiography can rule out obstructive coronary artery diseases and substitute invasive coronary angiography in many cases. In addition, coronary computed tomography angiography provides a unique information beyond stenosis grading as it can visualize atherosclerosis and quantify its extent. Qualitative and quantitative plaque assessment provides an incremental value in the prediction of future major adverse cardiac events. Moreover, determining adverse plaque features has a potential to identify advanced atherosclerosis and patients at increased risk of acute coronary syndrome. Nevertheless, challenges may emerge with the process of quantifying coronary plaques due to limited reproducibility, lack of automated, standardized and validated techniques. Therefore, reliable quantified data are scarce due to the various computed tomography scanners and software platforms and investigations with small sample sizes. Radiomics and machine learning-based image processing methods are relatively new in the field of cardiovascular plaque imaging. These techniques hold the promise to improve diagnostic performance, reproducibility and prognostic value of computed tomography based plaque assessment.

Prognostic accuracy of myocardial perfusion imaging in octogenarians

BackgroundMyocardial perfusion imaging (MPI) has an established role in the work-up of coronary artery disease (CAD), but its comparative accuracy is debated in elderly patients. We examined a large administrative database to appraise the performance of MPI in octogenarians. MethodsOur institutional database was queried for patients undergoing MPI without recent coronary revascularization or myocardial infarction (MI). We compared baseline, procedural, diagnostic, and prognostic features in patients aged < 80 vs ≥ 80 years with bivariate and propensity-adjusted analyses. ResultsFrom 13,254 patients, 12,737 (96.1%) were < 80 years old and 517 (3.9%) ≥ 80 years. Octogenarians were less likely to undergo exercise testing, had more severe and extensive myocardial ischemia (all P < 0.001), whereas CAD was more prevalent and diffuse in them (P = 0.012), and major adverse cardiac events more common during follow-up (P = 0.009). Diagnostic accuracy of MPI was similar or higher in octogenarians than in younger patients (e.g., sensitivity for three-vessel disease 92% in octogenarians vs 91% in younger patients), as was prognostic accuracy. Using propensity-matched analyses, MPI again yielded satisfactory prognostic accuracy in octogenarians. ConclusionsUse of MPI in octogenarians is associated with similar or better prognostic accuracy than in younger subjects.

Coronary CT-Derived Fractional Flow Reserve

Coronary artery disease (CAD) is the leading cause of mortality in the United States and is accountable for a significant portion of overall healthcare costs. Non-invasive imaging plays a major role in the modern workup of CAD. This article will educate the reader on the foundations of computed tomography-derived fractional flow reserve (CT-FFR) and provide guidance for its appropriate clinical use. Coronary computed tomography angiography (CCTA) has high sensitivity and negative predictive value to non-invasively rule out CAD. However, discrimination of ischemia-inducing lesions based on macroscopic anatomy derived from either CCTA or the gold standard for the detection of anatomic stenoses, invasive coronary angiography, is suboptimal. Invasive pressure wire-guided estimation of FFR across coronary stenoses yields reliable functional information regarding the effect of a lesion on myocardial blood supply. Recently, non-invasive methods have attempted to calculate FFR from CCTA datasets. CT-FFR allows for higher specificity compared to CCTA alone, while preserving the high sensitivity and negative predictive value of CCTA. Whereas off-site solutions for CT-FFR calculation have been heavily validated and are clinically available, other techniques that can be performed on-site have recently evolved and are under current investigation. Non-invasive CT-FFR has facilitated the reliable assessment of the hemodynamic significance of coronary artery stenosis, potentially increasing the specificity of the modality while maintaining its excellent sensitivity.

Diagnostic value of global myocardial perfusion reserve assessment based on coronary sinus flow measurements using cardiovascular magnetic resonance in addition to myocardial stress perfusion imaging.

Myocardial perfusion reserve (MPR) is defined as the maximal possible increase in myocardial blood flow (MBF) above baseline conditions. Global MBF can be measured non-invasively by means of coronary sinus flow velocity encoded cine (VENC) cardiovascular magnetic resonance (CMR). We aimed to explore the relationship between global MBF/MPR and the extent and severity of coronary artery disease (CAD) in patients referred for CAD work-up by adenosine-stress CMR. Fifty-eight patients with suspected obstructive CAD underwent both adenosine-stress CMR and invasive coronary angiography. In addition to standard cine- and late gadolinium enhancement (LGE)-imaging, first-pass myocardial perfusion imaging (MPI) and coronary sinus flow measurements (VENC) were performed at rest and during peak stress (after 140 µg/kg/min adenosine), respectively. Nineteen young patients with a very low CAD pre-test probability and normal adenosine-stress CMR formed the control group. Fifty-nine percent (n = 34) of the study group showed segmental, adenosine-induced myocardial perfusion defects compared to none of the control group (P < 0.001). Global MPR was lower in the study group compared to the control group: 2.3 (1.5-3.1) vs. 3.1 (2.0-4.3), P = 0.016. The SYNTAX score was higher in the study group patients with an impaired MPR (<2) compared to those with a preserved MPR (3.0 vs. 16.0, P = 0.01)-mainly due to higher prevalence of proximal epicardial stenoses (60% vs. 27%, P = 0.02) and multi-vessel disease (56% vs. 24%, P = 0.017). The diagnostic yield of stress CMR for the diagnosis of CAD (>50% stenosis) increased from 65to 88% when global MPR assessment was considered in addition to MPI (P = 0.025). Global MBF and MPR values correlate with the anatomical extent and complexity of CAD and increase the diagnostic yield of non-invasive stress CMR in the work-up of CAD. CMR-based MBF and MPR measurements may play a future role in the evaluation of the total ischaemic burden-particularly in patients with multi-vessel disease.

Quantitative Myocardial Perfusion with Dynamic Contrast-Enhanced Imaging in MRI and CT: Theoretical Models and Current Implementation.

Technological advances in magnetic resonance imaging (MRI) and computed tomography (CT), including higher spatial and temporal resolution, have made the prospect of performing absolute myocardial perfusion quantification possible, previously only achievable with positron emission tomography (PET). This could facilitate integration of myocardial perfusion biomarkers into the current workup for coronary artery disease (CAD), as MRI and CT systems are more widely available than PET scanners. Cardiac PET scanning remains expensive and is restricted by the requirement of a nearby cyclotron. Clinical evidence is needed to demonstrate that MRI and CT have similar accuracy for myocardial perfusion quantification as PET. However, lack of standardization of acquisition protocols and tracer kinetic model selection complicates comparison between different studies and modalities. The aim of this overview is to provide insight into the different tracer kinetic models for quantitative myocardial perfusion analysis and to address typical implementation issues in MRI and CT. We compare different models based on their theoretical derivations and present the respective consequences for MRI and CT acquisition parameters, highlighting the interplay between tracer kinetic modeling and acquisition settings.

Cardiac PET-CT and CT Angiography

Today coronary artery disease (CAD) is widely understood to constitute an advanced stage of atherosclerosis, an inflammatory pathology involving both coronary and extracoronary arteries. It is increasingly appreciated that perfusion imaging brings additional prognostic value as compared to morphological imaging alone, where myocardial perfusion abnormalities can be understood as the functional consequence of a broad range of present atherosclerotic vessel alterations, baring considerable significance for the diagnostic and prognostic work-up of CAD. Using recently introduced PET/CT hybrid scanners, the favorable characteristics of PET perfusion imaging and quantification can be further strengthened by adding CT morphological information, both components contributing to a comprehensive view on the heart and enabling combined morphological and functional imaging including three dimensional image fusion. Thus, cardiac PET/CT can provide both a reliable allocation of perfusion abnormalities to their supplying coronary artery and improved individual risk stratification for further clinical management.

Does quantification of myocardial flow reserve using rubidium-82 positron emission tomography facilitate detection of multivessel coronary artery disease?

BackgroundRelative myocardial perfusion imaging (MPI) is the standard imaging approach for the diagnosis and prognostic work-up of coronary artery disease (CAD). However, this technique may underestimate the extent of disease in patients with 3-vessel CAD. Positron emission tomography (PET) is also able to quantify myocardial blood flow. Rubidium-82 (82Rb) is a valid PET tracer alternative in centers that lack a cyclotron. The aim of this study was to assess whether assessment of myocardial flow reserve (MFR) measured with 82Rb PET is an independent predictor of severe obstructive 3-vessel CAD. MethodsWe enrolled a cohort of 120 consecutive patients referred to a dipyridamole 82Rb PET MPI for evaluation of ischemia neither with prior coronary artery bypass graft nor with recent percutaneous coronary intervention that also underwent coronary angiogram within 6 months of the PET study. Patients with and without 3-vessel CAD were compared. ResultsAmong patients with severe 3-vessel CAD, MFR was globally reduced (<2) in 88% (22/25). On the adjusted logistic Cox model, MFR was an independent predictor of 3-vessel CAD [.5 unit decrease, HR: 2.1, 95% CI (1.2-3.8); P = .015]. The incremental value of 82Rb MFR over the SSS was also shown by comparing the adjusted SSS models with and without 82Rb MFR (P = .005). Conclusion82Rb MFR is an independent predictor of 3-vessel CAD and provided added value to relative MPI. Clinical integration of this approach should be considered to enhance detection and risk assessment of patients with known or suspected CAD.

Cost-effectiveness of substituting dual-energy CT for SPECT in the assessment of myocardial perfusion for the workup of coronary artery disease

PurposeWe compared cost-effectiveness and potential lifetime benefits of using dual-energy computed tomography (DECT) for myocardial perfusion assessment instead of single photon emission computed tomography (SPECT) for the workup of coronary artery disease (CAD). Materials and methodsA decision and simulation model was developed to estimate cost and health effects of using DECT myocardial perfusion imaging instead of SPECT for identifying patients in need of invasive imaging and possible revascularization. The model was based on the performance indices of stress/rest DECT compared with stress/rest SPECT for detecting myocardial perfusion deficits in 50 patients (mean age 61±10 years) with CAD. Stress/rest perfusion and delayed enhancement cardiac MRI served as reference standard. For DECT a reimbursement of US$1700 was assumed but costs of cardiac MRI were not included in the model. All other actual healthcare costs in these patients were derived from MUSC's hospital billing system. ResultsCompared with cardiac MRI, DECT (versus SPECT) had 90% (85%) sensitivity and 71% (58%) specificity for identifying patients with obstructive CAD. Compared with the no imaging and no treatment strategy, routine SPECT gained 13.49 quality-adjusted life-years (QALYs) with an incremental cost-effectiveness ratio (ICER) of US$3557 (in 2010) per QALY. In comparison, DECT ICER was lower (US$3.191 per QALY, p=0.0002) and an additional 0.64 QALYs was obtained (total of 14.13 QALYs) if compared with the SPECT strategy as well as the no imaging and no treatment strategy. ConclusionUsing DECT as the first-line imaging test for myocardial perfusion for the workup of patients with CAD has the potential to provide gains in QALYs, while lowering costs if compared to routine myocardial perfusion SPECT.

Cardiac MRI detection of a rare case of familial cardiac amyloidosis (Ser23Asn): case report with literature review

Cardiac MRI detection of a rare case of familial cardiac amyloidosis (Ser23Asn): case report with literature review Joseph Daoko, Yaser Elnahar, Karim El Kersh, Naser Mohammad, Fayez ShamoonSt Michael&#39;s Medical Center, Newark, NJ, USAAbstract: Cardiac amyloidosis is a rare disease that has significant sequelae if undetected and treated early. We report a case of a rare genetic mutation that leads to cardiac amyloidosis. This is a case of a 41-year-old Peruvian male without any known past medical history but with a family history of sudden death. The patient complained of episodic left-sided chest pain for 1 month that was associated with shortness of breath. A subsequent admission and workup for coronary artery disease was negative, but an echocardiogram showed global left ventricular hypokinesia. Cardiac magnetic resonance imaging (MRI) was performed which was suggestive of cardiac amyloidosis. A subsequent abdominal fat biopsy and bone marrow biopsy failed to show evidence of amyloidosis. However, the endomyocardial biopsy was consistent with cardiac amyloidosis. Familial cardiac disease was suspected because of the family history of sudden death. As such, genetic testing was performed which yielded a very rare genetic mutation corresponding to amino acid 23 of the transthyretin protein. A review of the literature shows that this gene mutation (AGT23AAT, gene sequence; Ser23Asn, protein sequence) has been described only once previously. This case is unique in that the patient&#39;s amyloidosis was limited to the heart, without involvement of any other organ.Keywords: amyloidosis, mutation, cardiac disease, genetics, diagnosis

Pathophysiologic correlates of 82Rb biodistribution in cardiac PET/CT

PET perfusion imaging with (82)Rb is a powerful tool for evaluating coronary artery disease (CAD). Little is known about normal patterns or significance of (82)Rb lung distribution in the setting of heart disease. Herein, PET/CT hybrid imaging was used to obtain insights into the frequency and potential radiomorphologic correlates of altered (82)Rb distribution. Myocardial perfusion PET/CT studies of 58 patients referred for workup of CAD were analyzed [28 normal and 30 patients with low left ventricular ejection fraction (LVEF)]. Organ regions of interest were placed on PET images, and (82)Rb uptake was measured and compared under resting and stress conditions. Qualitatively increased lung uptake was observed in 13 patients-5 with normal LVEF(R) and 8 with reduced LVEF(R); 12 of 13 had lung infiltrates/atelectasis on CT. Lung to heart ratios in the normal and low EF groups were (mean ± SD) 0.168 ± 0.047 and 0.171 ± 0.075 at rest, and 0.128 ± 0.035 and 0.147 ± 0.067 during stress (p = 0.87 and 0.18, respectively). Lung to liver ratios were not significantly different between the two groups under stress or rest conditions. Increased lung uptake of (82)Rb occurs in a subset of patients referred for workup of CAD by PET/CT and may be influenced by primary parenchymal abnormalities and LV dysfunction. Thus, the relevance of pulmonary (82)Rb uptake as a marker of cardiac outcome may be limited. Larger studies are needed to determine how non-cardiac (82)Rb uptake and CT findings may be integrated to increase the diagnostic and prognostic value of cardiac PET/CT.

Definition of Vascular Territories on Myocardial Perfusion Images by Integration with True Coronary Anatomy: A Hybrid PET/CT Analysis

For interpretation of myocardial perfusion studies, tissue segments are usually assigned to coronary vascular territories based on general assumptions about the most frequent vascular distribution pattern. These assumptions may be inaccurate because of interindividual variability of coronary anatomy. This limitation may be overcome by hybrid imaging through the individual integration of coronary anatomy with myocardial tissue regions. We studied 71 consecutive patients who underwent (82)Rb perfusion PET/CT, including CT angiography, for work-up of coronary artery disease on a 64-slice PET/CT scanner. Coronary vessels as defined by CT were assigned to each of 17 myocardial segments for PET analysis using fusion images. Reassigned segmental maps were compared with standard assignment as proposed by the American Heart Association model, without knowledge of individual anatomy. The validity of segmental assignment was tested in 6 dogs by comparison of PET/CT with ex vivo dye staining of coronary territories. Dog studies showed excellent agreement between PET/CT-defined segments and ex vivo-stained territories (kappa, 0.80). In patients, 72% (51/71) demonstrated differences from the standard assignment in at least 1 myocardial segment; 112 of 1,207 segments were reassigned to nonstandard vascular territories. Most frequently, standard right coronary segments were reassigned to the left circumflex territory (39% of reassigned segments), standard circumflex segments were reassigned to the left anterior descending territory (30%), and standard left anterior descending segments were reassigned to either circumflex or right coronary (12% and 11%, respectively). In 27 studies with a myocardial perfusion defect, relative uptake in the vascular territory with the defect was significantly lower after CT-based reassignment and was higher in remote territories, resulting in better separation (ratio of defect to remote, 0.75 +/- 0.13 vs. 0.81 +/- 0.12 before reassignment; P = 0.0014). Standard assumptions about vascular territory distribution in myocardial perfusion analysis are frequently inaccurate because of morphologic variability of the coronary tree. If hybrid imaging has been used to study coronary anatomy and myocardial tissue perfusion, then localization of perfusion abnormalities should be based on CT-derived anatomy. This may bring about more accurate assignment to culprit vessels and thus improved guidance and monitoring of targeted therapy.

Comparison of Measures of Left Ventricular Function from Electrocardiographically Gated 82Rb PET with Contrast-Enhanced CT Ventriculography: A Hybrid PET/CT Analysis

Because of the ultrashort tracer half-life and high positron energy of (82)Rb, PET images acquired with this tracer are noisier and of lower resolution than those obtained with other PET tracers. The validity of electrocardiographic gating using (82)Rb for assessment of left ventricular (LV) function is not well established. To support feasibility, we compared functional parameters from gated (82)Rb PET with simultaneous high-resolution contrast-enhanced CT ventriculography, obtained as a byproduct a CT coronary angiography during hybrid cardiac PET/CT. A total of 24 patients underwent PET/CT, consisting of rest and dipyridamole (82)Rb perfusion studies and contrast-enhanced CT angiography, using a 64-slice scanner, for the workup of coronary artery disease. From gated PET images, LV ejection fraction (EF), end-diastolic volume (EDV), and end-systolic volume (ESV) were calculated using 2 commercial products. For functional CT analysis, commercial software using endocardial contour detection was applied. Inter- and intraobserver agreement was good for all methods. On CT, EF was 66% +/- 13%, ESV was 41 +/- 29 mL, and EDV was 115 +/- 36 mL. On PET, EF during dipyridamole was 56% +/- 15% and 52% +/- 15% using the 2 commercial products (P < 0.05 vs. CT), ESV was 36 +/- 28 and 47 +/- 35 mL (P = not significant vs. CT), and EDV was 75 +/- 30 and 91 +/- 33 mL (P < 0.05 vs. CT). Correlations with CT were 0.85 and 0.87 for EF using commercial software, 0.76 and 0.88 for ESV, and 0.60 and 0.68 for EDV (P < 0.01 for all). Bland-Altman analysis confirmed systematic underestimation of EF and EDV by PET versus CT but did not show a significant deviation from linearity. Global LV function can be measured reproducibly from gated (82)Rb PET, using different available software products. However, underestimation of EF by (82)Rb PET, compared with CT ventriculography, is present, which is a result of underestimation of EDV from count-poor ED frames. This underestimation needs to be considered for clinical interpretation of (82)Rb PET.

Perfusion weighted color maps for enhanced visualization of myocardial infarction by MSCT: preliminary experience

The reliable detection of myocardial perfusion defects and myocardial infarction (MI) is of great interest in the comprehensive workup of coronary artery disease. The aim of this study was to optimize the ability of contrast-enhanced cardiac multislice spiral computed tomography (MSCT) for detecting hypoperfused myocardium as surrogate marker of MI using a newly developed post-processing technique. First a model-based software tool for semi-automated detection of the long axis of the left ventricle and assignment of left-ventricular segments was developed using a region growing algorithm and a point distribution model. To visualize changes of the myocardial contrast enhancement pattern color coding was performed after spreading of the attenuation values. 15 patients (12 men, mean age 57 +/- 15 years) with a history of MI underwent cardiac MSCT (16 x 0.75 mm, 120 kV, 550 mA s(eff.), 100 ml Iopromide) and contrast enhanced delayed enhanced magnetic resonance imaging (DE-MRI) after administration of 0.2 mmol Gd-DTPA/kg/bodyweight as reference standard. Presence of infarction was assessed from MSCT, post-processed MSCT images and DE-MRI using a 17-segment model of the left ventricle. On DE-MRI MI was present in 78/255 myocardial segments. From conventional MSCT images MI was detected in 63/255 segments (5 false positive; sensitivity 74.4%; specificity: 97.1%), while on post-processed images MI was assigned to 74/255 segments (6 false positive; sensitivity 87.2%; specificity: 96.6%). Agreement between DE-MRI and conventional MSCT images for detecting MI was kappa = 0.756. Using post-processed images agreement improved to kappa = 0.850. MSCT detection of hypoperfused myocardium as surrogate for MI can be improved using dedicated post processing algorithms.

Cardiovascular nuclear imaging: from perfusion to molecular function

Myocardial perfusion scintigraphy (MPS) is a well established clinical imaging technique for the diagnostic and prognostic workup of coronary artery disease, and it has been the mainstay of cardiovascular radionuclide...

Mammography as Screening for Coronary Artery Disease

Coronary artery disease (CAD) is the leading cause of death in American women. Screening mammograms are recommended for women starting at age 40 for the early detection of breast cancer. An additional benefit of this routine screening tool may be to detect breast arterial calcifications (BAC) as a possible sign of CAD. The purpose of this study was to determine further the relationship between mammographically detected BAC and CAD. The medical records of 44 women who had undergone coronary artery bypass grafting at our institution over 5 years were reviewed. These mammograms were examined for evidence of BAC. For all women included in the study, 18 of 44 (41%) had evidence of BAC on screening mammogram. This was statistically significant (P < 0.0001) compared with the prevalence of BAC reported in the general population in previous studies. Most were also overweight (61.1%), had hypertension (88.8%), and hypercholesterolemia (55.5%). This is the first study to look at the direct correlation between patients with known CAD requiring revascularization and BAC. Perhaps women with BAC seen on screening mammography should undergo further workup for CAD, with the potential benefit of early intervention.