Comparison of the diagnostic accuracies of very low stress-dose with standard-dose myocardial perfusion imaging: Automated quantification of one-day, stress-first SPECT using a CZT camera.

BACKGROUND: Previous studies have demonstrated accurate diagnosis of reduced dose myocardial perfusion imaging (MPI) using Cadmium-Zinc-Telluride (CZT) technology. We compared the diagnostic performances of very low stress-dose (<2 mSv) with standard-dose stress-first, quantitative MPI using a CZT camera. METHODS: Patients without known coronary artery- disease who underwent a stress-first Tc-99 m sestamibi CZT-MPI and invasive coronary angiography (ICA), and low-risk patients without ICA were included. A stress-rest standard-dose (10/30 mCi) MPI and a low-dose (5/15 mCi) MPI were compared. Normal limits for quantification were developed from 40 (20 males) low-risk patients, and total perfusion deficit (TPD) was derived. RESULTS: 208 patients who underwent MPI and ICA, and 76 low-risk patients were included. Of these, 128 had a standard-dose MPI and 156 had a low-dose MPI. Stress-doses in low-dose and standard-dose groups were 5.9 ± 1.2 vs 10.2 ± 0.5 mCi (1.7 ± 0.3 vs 3.0 ± 0.1 mSv), respectively, P < 0.001, and stress-rest effective radiation was 6.9 ± 1.1 vs 11.7 ± 0.4 mSv, respectively, P < 0.001. Sensitivity, specificity, and accuracy values in the low-dose and standard-dose groups were 86.1%, 76.6%, and 81.4%; and 90.6%, 78.1%, and 84.4%, respectively, P = ns. Using TPD prone, specificity values were 84.9% and 80.3%, respectively, P = ns. CONCLUSION: One-day stress-first MPI with 50% radiation reduction and a very low stress-dose (<2 mSv) using CZT technology and quantitative supine and prone analysis provided a high diagnostic value, similar to standard-dose MPI.

Rotational method simplifies 3-dimensional measurement of left atrial appendage dimensions during transesophageal echocardiography.

BACKGROUND: Not all echo laboratories have the capability of measuring direct online 3D images, but do have the capability of turning 3D images into 2D ones "online" for bedside measurements. Thus, we hypothesized that a simple and rapid rotation of the sagittal view (green box, x-plane) that shows all needed left atrial appendage (LAA) number of lobes, orifice area, maximal and minimal diameters and depth parameters on the 3D transesophageal echocardiography (3DTEE) image and LAA measurements after turning the images into 2D (Rotational 3DTEE/"Yosefy Rotation") is as accurate as the direct measurement on real-time-3D image (RT3DTEE). METHODS: We prospectively studied 41 consecutive patients who underwent a routine TEE exam, using QLAB 10 Application on EPIQ7 and IE33 3D-Echo machine (BORTHEL Phillips) between 01/2013 and 12/2015. All patients underwent 64-slice CT before pulmonary vein isolation or for workup of pulmonary embolism. LAA measurements were compared between RT3DTEE and Rotational 3DTEE versus CT. RESULTS: Rotational 3DTEE measurements of LAA were not statistically different from RT3DTEE and from CT regarding: number of lobes (1.6 ± 0.7, 1.6 ± 0.6, and 1.4 ± 0.6, respectively, p = NS for all); internal area of orifice (3.1 ± 0.6, 3.0 ± 0.7, and 3.3 ± 1.5 cm(2), respectively, p = NS for all); maximal LAA diameter (24.8 ± 4.5, 24.6 ± 5.0, and 24.9 ± 5.8 mm, respectively, p = NS for all); minimal LAA diameter (16.4 ± 3.4, 16.7 ± 3.3, and 17.0 ± 4.4 mm, respectively, p = NS for all), and LAA depth (20.0 ± 2.1, 19.8 ± 2.2, and 21.7 ± 6.9 mm, respectively, p = NS for all). CONCLUSION: Rotational 3DTEE method for assessing LAA is a simple, rapid and feasible method that has accuracy similar to that of RT3DTEE and CT. Thus, rotational 3DTEE ("Yosefy rotation") may facilitate LAA closure procedure by choosing the appropriate device size.

A New Method for Direct Three-Dimensional Measurement of Left Atrial Appendage Dimensions during Transesophageal Echocardiography.

AIMS: Currently, two-dimensional transesophageal echocardiography (2DTEE) at a cut-plane angulation of 135° is the recommended method to size maximal left atrial appendage (LAA) orifice diameter before introducing a percutaneous LAA closure device. We compared real time three-dimensional TEE (RT3DTEE) and 2DTEE for measuring LAA dimensions versus computed tomography (CT) as gold standard. METHODS AND RESULTS: We prospectively studied 30 consecutive patients who underwent a routine TEE examination, using QLAB 10.0 Application on EPIQ7 iE33 3D echo machine between December 2012 and December 2013. All patients underwent 64-slice CT before pulmonary vein isolation or for workup of pulmonary embolism. LAA measurements were compared between 135 2DTEE and RT3DTEE. Results were compared with CT measurements. Using RT3DTEE, larger LAA diameters were measured versus 2DTEE (23.5 ± 3.9 vs. 24.5 ± 4.7 mm). In seven patients (23.3%), the measurements in 135° 2DTEE were smaller than the cut-plane angulation with maximal orifice diameter. RT3DTEE measurements of LAA were not different from CT regarding number of lobes, area of orifice, and maximal diameter. LAA volume could not be measured directly using RT3DTEE. No difference was found between LAA depth using RT3DTEE (19.5 ± 2.3 mm) vs. CT (19.6 ± 2.3, P = NS) and 2DTEE (19.4 ± 2.2 mm) vs. CT (P = NS). However, RT3DTEE (24.5 ± 4.7 mm) vs. CT (24.6 ± 5, P = NS) was more accurate in measuring maximal LAA diameter compared to 2DTEE (23.5 ± 3.9 mm) vs. CT (P < 0.01). CONCLUSION: RT3DTEE method is more accurate than 2DTEE for assessment of maximal LAA orifice diameter. Bedsides, RT3DTEE LAA measurements are not statistically different from CT. Thus, RT3DTEE may facilitate LAA closure procedure by choosing the appropriate device size.

[Fast myocardial perfusion imaging of stress--first protocol using CZT-technology: a preliminary report of the correlation to invasive coronary angiography].

BACKGROUND: Myocardial perfusion imaging (MPI) is valuable for diagnosing coronary disease and assessing the risk of cardiac events. New technology based on semiconductors (Cadmium zinc telluride-CZT) enables reducing imaging time and improving image quality. METHODS: We retrospectively identified 57 patients who underwent MPI at Assuta using a CZT camera and invasive coronary angiography (ICA) within 60 days following nuclear testing without an intervening cardiac event, and without history of coronary disease. In addition, 25 patients with low pretest likelihood who did not undergo ICA were included in the study. All 82 patients underwent fast-acquisition, stress-first Tc-99m sestamibi MPI using very short imaging time (stress: 5:00 min., prone: 3:40 min. and rest: 2:00 min]. A low-dose stress injection (9-12 mCi, ≤ 3.5 mSv) and high rest-dose (25-32 mCi) with adjustment to patient weight were administered. Semi-quantitative visual analysis utilized a 17-segment model, 0-4 scale (0 = normal uptake, 4 = absent uptake). The summed stress score (SSS) representing stress perfusion abnormality was converted to a percentage of abnormal myocardium (SSS% = SSS/68*100). ICA served as a gold standard for the nuclear perfusion findings. RESULTS: The mean age was 60.1 ± 11 years and most subjects were men (58, 70.7%). Compared to low-risk patients, patients who underwent ICAwere older, and had a higher frequency of hypertension, diabetes mellitus and dyslipidemia. A low-dose stress-only test with low radiation exposure ≤ 3.5 mSv) was frequent among low-risk patients (18/25-72%). ROC analysis for identification of angiographic coronary disease by SSS% demonstrated area under curve of 0.923, 95% confidence interval 0.859-0.988, p < 0.001. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were: 91.4%, 81.2%, 78.3%, 97.2% and 86.6%, respectively. CONCLUSION: Fast, low-dose stress MPI using CZT technology enables semi-quantitative analysis with high diagnostic value for coronary disease.

The prognostic value of post-exercise blood pressure reduction in patients with hypertensive response during exercise stress test.

BACKGROUND: Hypertensive response at peak-exercise and during the recovery phase of exercise stress test (ET) is associated with poor cardiovascular prognosis. We investigated whether decrease in blood pressure (BP) from peak to post-exercise would identify a subgroup at higher cardiovascular risk. METHODS: Eighty-six non-hypertensive patients (0-4 cardiovascular risk factors) with hypertensive reaction at peak-ET (systolic>180 mm Hg and/or diastolic>100 mm Hg) were divided based on BP 5 min after exercise termination into two groups: Normal response (NrmR) (<160/90 mm Hg), Hypertensive response (HypR) (>/=160/90 mm Hg). Five years later the prevalence of cardiovascular risk factors and cardiovascular morbidity and mortality was assessed for each group. RESULTS: Both groups had similar pre- and peak-exercise BP. However the HypR group had higher post-exercise BP (systolic: 163+/-13 vs. 125+/-14 mm Hg, respectively, p<0.01, and diastolic: 74+/-6 vs. 75+/-4 mm Hg, respectively, p<0.01), smaller decrease in BP after exercise (Delta systolic: 46.9+/-3.1 vs. 73.9+/-3.6 mm Hg, respectively, p<0.01, Delta diastolic: 12.4+/-1.5 vs. 26.5+/-2.2 mm Hg, respectively, p<0.01), and higher post- than pre-exercise BP (Delta systolic: 24.5+/-3.5 vs. -6+/-4.1 mm Hg, respectively, p<0.01, A diastolic: 19+/-2.1 vs. -13+/-2.3 mm Hg, respectively, p<0.01). Five years later, HypR group had higher prevalence of abnormal cholesterol serum level (p<0.01), hypertension (p<0.01) and combined ischemic heart disease and cerebrovascular disease (RR 1.32, 95% CI=1.13-1.54, p<0.01). CONCLUSION: During ET evaluation, it is important to evaluate the BP at 5 min after exercise because reduced BP drop, at this routinely measured point, identifies a subgroup with higher cardiovascular risk.