Jacek Kuśmierek

Accelerated Stress Real-Time Myocardial Contrast Echocardiography for the Detection of Coronary Artery Disease: Comparison with 99mTc Single Photon Emission Computed Tomography

OBJECTIVE The aims of this prospective study were to compare the diagnostic value of accelerated vasodilator stress real-time myocardial contrast echocardiography (MCE) and single photon emission computed tomography (SPECT) against coronary angiography and to evaluate whether the addition of MCE perfusion data improves the diagnostic accuracy of stress echocardiography. METHODS A total of 103 patients with suspected or known stable coronary artery disease (CAD) underwent SPECT and accelerated high-dose dipyridamole (0.84 mg/kg intravenously for 4 minutes) atropine (up to 1 mg intravenously) stress real-time qualitative MCE. The presence of CAD was detected by coronary angiography. RESULTS CAD defined as >or= 70% stenosis was detected in 77% of patients, whereas 86% of patients had CAD defined as >or= 50% stenosis. In a territory-by-territory analysis, the concordance between MCE and SPECT in detecting perfusion defects varied from 72.8% (kappa = 0.386) to 89.3% (kappa = 0.642). There were no significant differences between MCE and SPECT in sensitivity, specificity, and diagnostic accuracy for identifying patients with CAD. Combining MCE and wall motion abnormality analysis significantly improved the sensitivity of the test compared with wall motion abnormality analysis alone. CONCLUSIONS Accelerated vasodilator stress real-time MCE yields a good concordance with SPECT in detection of perfusion defects and a similar diagnostic value for the detection of CAD. The addition of MCE perfusion data improves the diagnostic value of stress echocardiography.

Gated 99mTc-MIBI single-photon emission computed tomography for the evaluation of left ventricular ejection fraction: comparison with three-dimensional echocardiography

ObjectiveParameters of left ventricular systolic function directly influence the management of patients with suspected coronary artery disease (CAD). Quantitative gated single-photon emission computed tomography (QGS; Cedars-Sinai Medical Center, Los Angeles, CA, USA) allows the computation of left ventricular ejection fraction (LVEF) from myocardial perfusion imaging studies which are frequently performed on patients with suspected CAD. Three-dimensional (3D) echocardiography is considered to be the echocardiographic “gold standard” for the quantification of LVEF. We sought to compare QGS with 3D echocardiography in the evaluation of EF in patients with suspected CAD.MethodsNinety-one consecutive patients with suspected CAD, scheduled for coronary angiography, underwent rest electrocardiographic-gated technetium-99m methoxyisobutylisonitrile SPECT (G-SPECT) with measurement of LVEF by QGS and transthoracic 3D echocardiography with off-line measurement of LVEF (Tomtec 4D LV Analysis 1.1). The diagnosis of CAD was based on coronary angiography, performed on every patient.ResultsNine patients were excluded from the analysis owing to unsuitability for 3D echocardiography (8 patients) or G-SPECT (1 patient). In the remaining group of 82 patients, 71 (87%) had significant CAD, 34 (42%) had a history of myocardial infarction, and 50 (61%) had perfusion defects at rest G-SPECT images. The mean LVEF measured by QGS and 3D echocardiography was 53 ± 13% and 53 ± 10%, respectively. The mean difference in LVEF between 3D echocardiography and QGS was 0.1 ± 6.0% (P = 0.87), and the correlation between the values obtained by both methods was high (r = 0.88, P < 0.001). The largest discrepancies were observed in patients with small ventricular volumes.ConclusionsIn patients undergoing diagnostic work-up for CAD, the measurement of LVEF by QGS algorithm provides high correlation and satisfactory agreement with the results of reference ultrasound method-3D echocardiography.

Perfusion lung scintigraphy for the prediction of postoperative residual pulmonary function in patients with lung cancer

BACKGROUND Accurate prediction of postoperative pulmonary function in patients with non-small cell lung cancer is crucial for proper qualification for surgery, the only effective therapeutic method. The aim of the study was to select the most accurate method for acquisition and processing of lung perfusion scintigraphy (LPS) combined with spirometry for prediction of postoperative pulmonary function in patients qualified for surgery. MATERIAL AND METHODS LPS was performed in 70 patients (40 males, 30 females), with preoperative spirometry (mean FEV1preop = 2.26 ± 0.72 L), after administration of 185 MBq of 99mTc-microalbumin/macroaggregate, using planar (appa) and SPECT/CT methods. Predicted postoperative lung function (FEV1pred) was calculated as a part of active lung parenchyma to remain after surgery. A non-imaging segment counting method was also applied. FEV1pred(appa, SPECT, SPECT/CT, segm.) were further compared with actual FEV1postop values obtained from postoperative spirometry. RESULTS In the whole studied group (47 lobectomies, 23 pneumonectomies) mean value of FEV1postop was equal to 1.76 (± 0.56) L. FEV1pred(appa, SPECT, SPECT/CT, segm.) were equal to 1.75 (± 0.58) L, 1.71 (± 0.57) L, 1.72 (± 0.57) L and 1.57 (± 0.58) L, respectively. A segment counting method systematically lowered predicted FEV1 values (p < 10-5). Moreover, in 31 patients with FEV1preop < 2 L error of predicted values was assessed with Bland-Altman method. Mean absolute differences FEV1postop - FEV1pred amounted to: appa - (0.04 ± 0.13) L, SPECT - (0.07 ± 0.14) L, SPECT/CT - (0.06 ± 0.14) L and segm. - (0.21 ± 0.19) L, respectively. Lower limit of 95% confidence interval calculated for planar - optimal method, was equal to -220 mL (also determined separately in subgroups after lobectomy and pneumonectomy). CONCLUSIONS This study shows that planar LPS may be applied for prediction of postoperative pulmonary function in patients qualified for pneumonectomy and lobectomy. If actual FEV1postop value is to be ≥ 800 mL, predicted value should exceed 1000 mL.

Long-term prognostic value of inducible and resting perfusion defects detected by single-photon emission computed tomography in the era of wide availability of coronary revascularization.

To assess the long‐term prognostic value of various types of perfusion defects detected by single‐photon emission computed tomography (SPECT) in patients with stable angina.

Patient exposure to ionising radiation due to nuclear medicine cardiac procedures

Nuclear cardiology procedures are among the most extensively performed radionuclide studies. Procedures for the assessment of myocardial perfusion, contractile function and metabolism have gained a prominent position in clinical practice. Health risk to patients from radiopharmaceuticals results only from exposure to ionizing radiation. Nuclear medicine diagnostic procedures,including the cardiological ones, are accompanied by a very small risk of radiation induced malignant tumours. Death risk from stress and rest perfusion of myocardium (effective dose of about 10 mSv) could be estimated as lower than 0.1 per mille.

Diagnostic value of optimised real-time sonoelastography in the assessment of liver fibrosis in chronic hepatitis B and C

Aim To optimise the method of real-time elastography (RTE) in the assessment of liver fibrosis using an in-house prepared method for elastogram analysis, as well as a semiquantitative analysis based on newly introduced parameters. Material and methods Sonoelastography was performed in 94 patients with various degrees of liver fibrosis and also in 25 healthy volunteers. As a reference method for diagnostic efficacy of sonoelastography-based parameters used for the assessment of fibrosis degree in patients with chronic B and C hepatitis, a liver biopsy was used. Patient’s elastograms were analysed using in-house prepared software, Pixel Count, calculating two semiquantitative parameters: mean stiffness fraction (MSF%) and intrinsic stiffness ratio (ISR). Results Statistically significant differences between distributions of the above presented parameters for different degrees of liver fibrosis were revealed. Indices of diagnostic efficacy for detection of significant liver fibrosis (F ≥ 2) using MSF% amounted to: sensitivity – 76%, specificity – 87% and ISR: 81% and 87%, respectively. Sensitivity of both parameters in detection of cirrhosis (F = 4) was equal to 88% and specificity amounted to: for MSF% – 84% and ISR – 86%. Interobserver reproducibility determined for both of the above parameters was high, intraclass correlation coefficients (ICC) were 0.91 for MSF% and 0.93 for ISR. Conclusions Real-time elastography applied in this study, using in-house prepared Pixel Count software, provided good reproducibility and diagnostic efficacy, especially specificity, in the assessment of liver fibrosis degree.

Diagnostic performance of myocardial perfusion single-photon emission computed tomography with attenuation correction

BACKGROUND Myocardial perfusion single-photon emission computed tomography (SPECT) is one of the basic tools used for the purpose of diagnosis of coronary artery disease (CAD), prognosis of its unfavourable consequences, and evaluation of therapy effectiveness. However, its efficacy is compromised by a relatively low specificity of detection of perfusion defects, which is attributed to attenuation of gamma rays inside the patients body, causing artefacts erroneously taken for perfusion defects. It is expected that attenuation correction (AC) could eliminate such artefacts. AIM To evaluate whether visual, semi-quantitative analysis of attenuation-corrected myocardial perfusion imaging provides an advantage over a non-corrected study. METHODS A retrospective study applying AC was performed in 107 patients who had coronary angiography within three months. Patients underwent a stress/rest Tc-99m methoxyisobutylisonitrile (MIBI, POLATOM) double day SPECT/CT myocardial perfusion imaging. Images were analysed by two experienced nuclear medicine specialists (a consensus) applying a visual semiquantitative method. Coronary angiography findings were used as a reference for the analysis of diagnostic performance of myocardial perfusion study protocols. RESULTS AC increased the specificity of detection of CAD in the whole group of patients from 63% to 86% (p = 0.0005), with a slight reduction in sensitivity (from 83% to 79%). The improved specificity was also noted in subgroups of male and female patients. Accuracy in the whole group of patients increased from 71% to 83% (p = 0.01). AC improved the specificity and accuracy of the method in the detection of perfusion defects in the right coronary artery (RCA) area from 73% to 88% (p = 0.005) and from 74% to 83% (p = 0.04), respectively, and the accuracy of the method in the left anterior descending (LAD) artery area from 79% to 87% (p = 0.043). It also reduced the number of ambiguous results of the study. CONCLUSIONS AC improved the diagnostic performance of myocardial perfusion study in the detection of CAD and identification of critically stenosed LAD and RCA vessels, with enhanced comfort of study interpretation.

Safety of non-invasive cardiovascular imaging techniques. Expert consensus statement of the Polish Clinical Forum for Cardiovascular Imaging

Polskie Kliniczne Forum Obrazowania Serca i Naczyn: Edyta Plonska-Gościniak, Magdalena Kostkiewicz, Piotr Lipiec, Tomasz Miszalski-Jamka, Andrzej Szyszka, Mieczyslaw Pasowicz, Andrzej Gackowski, Tomasz Kukulski, Miroslaw Dziuk, Cezary Kepka, Mariusz Skowerski, Zbigniew Gąsior, Jerzy Walecki, Piotr Szymanski, Katarzyna Mizia-Stec, Anna Klisiewicz, Piotr Hoffman, Piotr Podolec, Piotr Pruszczyk, Jaroslaw D. Kasprzak, Adam Torbicki

Detection of single-vessel coronary artery disease by dipyridamole stress echocardiography: no longer a problem?

We aimed to evaluate whether addition of myocardial contrast echocardiography (MCE) perfusion data improves the sensitivity of stress echocardiography for detection of single‐vessel coronary artery disease (svCAD) and to compare the diagnostic value of MCE and single‐photon emission computed tomography (SPECT) for detection of svCAD.

Modification of a two blood sample method used for measurement of GFR with 99mTc-DTPA

BACKGROUND Measurements of GFR may be performed with a slope/intercept method (S/I), using only two blood samples taken in strictly defined time points. The aim of the study was to modify this method in order to extend time intervals suitable for blood sampling. Modification was based on a variation of a Russel et al. model parameter, selection of time intervals suitable for blood sampling and assessment of uncertainty of calculated results. MATERIAL AND METHODS Archived values of GFR measurements of 169 patients with different renal function, from 5.5 to 179 mL/min, calculated with a multiple blood sample method were used. Concentrations of a radiopharmaceutical in consecutive minutes, from 60th to 190th after injection, were calculated theoretically, using archived parameters of biexponential functions describing a decrease in 99mTc-DTPA concentration in blood plasma with time. These values, together with injected activities, were treated as measurements and used for S/I clearance calculations. Next, values of S/I clearance were compared with the multiple blood sample method in order to calculate suitable values of exponent present in a Russels model, for every combination of two blood sampling time points. A model was considered accurately fitted to measured values when SEE ≤ 3.6 mL/min. Assessments of uncertainty of obtained results were based on law of error superposition, taking into account mean square prediction error and also errors introduced by pipetting, time measurement and stochastic radioactive decay. RESULTS The accepted criteria resulted in extension of time intervals suitable for blood sampling to: between 60 and 90 minutes after injection for the first sample and between 150 and 180 minutes for the second sample. Uncertainty of results was assessed as between 4 mL/min for GFR = 5-10 mL/min and 8 mL/min for GFR = 180 mL/min. CONCLUSIONS Time intervals accepted for blood sampling fully satisfy nuclear medicine staff and ensure proper determination of GFR. Uncertainty of results is entirely acceptable and for high GFR values even comparable with uncertainty of multi-sample measurements.