Myocardial SPECT Research Articles

Association between plasma homocysteine and myocardial SPECT abnormalities in patients referred for suspected myocardial ischaemia

Elevated plasma homocysteine level has emerged as a relatively newly recognised risk factor for coronary artery disease (CAD). However, reduction of plasma homocysteine levels in large prospective studies did not appear to reduce the risk for subsequent cardiac events. In this study, we investigated the association between plasma homocysteine levels and quantitative indices of myocardial perfusion SPECT imaging in patients referred for myocardial ischaemia. Quantitative myocardial perfusion SPECT indices were obtained for 120 patients who were recruited for the study. All patients underwent a two-day rest-stress myocardial perfusion imaging. Plasma venous sampling was done on all patients after an overnight fast. Of the 120 participants (mean age 56 years, 53% males), 33% had elevated plasma homocysteine levels. The plasma homocysteine level was then compared to the results of imaging and other known risk factors. After adjustment for traditional risk factors of coronary artery disease, patients with elevated homocysteine levels had a significantly higher mean summed stress score (SSS) (11.3 vs 6.9, p = 0.02) than patients with a normal homocysteine level. This was true for both single- and multivessel disease. Also, patients with elevated homocysteine levels had a higher stress end-systolic volume (SESV) (137 vs 105 ml, p = 0.03) and lower post-stress left ventricular ejection fraction (SEF) (54 vs 64%, p = 0.02). The patients with elevated plasma homocysteine levels also had a significantly lower mean body mass index (BMI) (26.6 vs 30.6 kg/m(2), p = 0.002). There was a significant relationship between the total number of known risk factors in a patient with CAD and the proportion of patients presenting with elevated plasma homocysteine levels (p = 0.03). Also, the extent of infarct, as measured by the summed rest score (SRS), was more closely correlated with an elevated homocysteine level than with the degree of ischaemia. There was a correlation between plasma homocysteine level and the presence and extent of myocardial perfusion abnormalities in patients with established coronary artery disease, in particular those with multiple risk factors and multi-vessel infarction.

PMD37 The Cost-Effectiveness Analysis of CT Coronary Angiography Versus Myocardial Spect for the Diagnosis of Ischemic Heart Disease in Patients with Chest Pain

PMD37 The Cost-Effectiveness Analysis of CT Coronary Angiography Versus Myocardial Spect for the Diagnosis of Ischemic Heart Disease in Patients with Chest Pain

Evaluation of the therapeutic effect of Tongxinluo for acute myocardial infarction using 99Tcm-MIBI SPECT imaging

Objective To investigate the treatment effect of Tongxinluo for revasculatization improvement after PCI using 99Tcm-MIBI SPECT imaging for AMI patients.Methods A total of 38 patients with AMI were randomly divided into a control group (PCI only,18 patients) and Tongxinluo treatment group (20 patients).99Tcm-MIBI myocardial SPECT was performed 7 d and 180 d after PCI.The left ventricular myocardium was divided into 17 segments.The myocardial 99Tcm-MIBI uptake was scored semiquantitatively.The number and scores of abnormal perfusion segments were evaluated in all patients.T-test and x2 test were used to compare the difference between the two groups using SPSS 11.5.Results The total number of abnormal segments in the treatment group was 59 at 7 d after PCI,among which 37 (62.7％,37/59) had improved perfusion at 180 d after PCI.In the control group,64 abnormal segments were found at 7 d after PCI; however,the perfusion was improved in only 26 (40.6％,26/64) segments at 180d after PCI.By comparing the myocardial perfusion defect scores,there was a significant difference (x2 =5.994,P ＜ 0.05) between the control and treatment groups.The total scores of treatment and control groups were 6.2±8.4 and7.4 ±6.9 (t =0.5,P＞0.05),respectively,at7 d after PCI and 3.4 ±4.6 and 6.8 ±5.9(t =2.1,P ＜ 0.05),respectively,at 180 d after PCI.The changes in scores were 2.9 ± 5.7 and 0.6 ±3.3(t =1.5,P ＞0.05) in the treatment and control groups between 7 d and 180 d after PCI.Conclusion Tongxinluo can reduce the number of persistent perfusion defects after PCI treatment in patients with AMI,and thus has a potential role in preventing revascularization failure. Key words: Myocardial infarction; Myocardial reperfusion; Tongxinluo; Tomography,emission-computed, single-photon; MIBI

Quantification of diagnostic accuracy using nitrate enhanced Tc-99m sestamibi gated myocardial SPECT in assessing myocardial viability: prospective analysis

The aim of this prospective study was to assess myocardial viability with nitrate-enhanced Tc-99m sestamibi gated single-photon emission computed tomography in patients with known coronary artery disease. We enrolled 48 consecutive patients (39 men, 9 women) aged 24-82 years, with coronary artery disease and history of myocardial infarction. A Tc-99m sestamibi study was conducted at rest as baseline, followed by a nitrate-enhanced study the next day. Of 960 segments analyzed, 244 of 480 in the left anterior descending coronary artery territory showed viability on the baseline study, and 276 were viable according to the nitrate-enhanced study. Similarly, of 192 right coronary segments analyzed, 148 showed viability on the baseline study compared to 153 on the nitrate study. Of 288 left circumflex territory segments analyzed, 206 showed viability on the baseline study compared to 241 on the nitrate study. The overall improvement of viability with the nitrate study was 12.04%. On the gated studies, the overall improvement with nitrate was 2.02%. The gated study also allowed grading of wall motion and thickness. It was concluded that nitrate-augmented Tc-99m sestamibi myocardial imaging significantly improved the detection of hibernating myocardium, with gated images further improving the accuracy of detection in borderline cases.

Reduced-count myocardial perfusion SPECT with resolution recovery

The aim of this study was to determine whether resolution recovery (RR) iterative reconstruction algorithms can consistently produce diagnostic quality myocardial perfusion SPECT images for the patient population routinely scanned in this department. Reduced-count data were compared with full-count data without RR according to our established protocol. The desired outcome would be to implement the software to allow a reduction in the administered activity for routine myocardial SPECT. Half-count SPECT data were derived from full-count datasets for 53 stress and rest routine myocardial SPECT scans on a GE Infinia camera. Full-count data were reconstructed using standard non-RR ordered subset expectation maximization reconstruction, whereas half-count data were reconstructed using Evolution RR software. Myocardial functional values, image quality and report outcomes of the full-count and half-count reports were compared. Sequential full-time and half-time myocardial SPECT acquisitions were performed for 15 stress and rest studies on a Siemens c.cam dedicated cardiac camera. Half-count data were reconstructed using Siemens Flash 3D RR. No degradation in image quality was found when comparing full-count and half-count studies from the Infinia. Ten percent of the half-count studies from the c.cam were considered slightly worse than full-count data. Statistically significant differences in some full-count versus half-count functional values were found but the actual mean differences were not considered clinically significant. No difference was found for 44 out of 53 full-count versus half-count reports, a minor difference for seven out of 53 and a significant difference in two cases. RR was found to produce diagnostic image quality for nearly all scans, but it was felt that a reduction of 50% from our standard protocol was too great. A proposed reduction of 33% administered activity was considered acceptable to produce consistently adequate diagnostic images for both manufacturers.

Facteurs influençant la détectabilité de l’activité myocardique en caméra à semi-conducteurs

Body weight was already shown to be a major factor for the detectability of myocardial activity with conventional cameras and thus, for the optimization of injected activities and or recording times. This study was aimed to identify the factors affecting this detectability on a new solid-state camera showing a high sensitivity of detection (D.SPECT camera Cyclopharma®). Patients and methodsThe study population involved 101 patients, who underwent myocardial SPECT with Sestamibi on a one-day stress/rest protocol. Each conventional acquisition (DST-XL General Electric Healthcare® USA) was immediately followed by a D-SPECT® one. Myocardial activity was determined on each acquisition in counts per seconds and expressed in fraction of the injected activity for assessing the detectability of myocardial activity. ResultsMyocardial activity was on average 12±3 fold higher when recorded with the D-SPECT® camera than with the DST-XL® one. Body weight and especially body mass index (BMI) were the most significant correlates of the detectability of myocardial activity for both cameras. According to these correlations, an increase in the BMI from 25 to 35kg/m was associated with a 47% decrease in the detectability of myocardial activity at stress with the DST-XL® and of only 30% with the D-SPECT. ConclusionThe detectability of myocardial activity provided by the D.SPECT camera is dramatically higher than that documented for conventional cameras of the DST-XL® type and is affected by the increase in body weight and in body mass index but at a lower rate than for the Anger camera.

Hybrid SPECT/cardiac‐gated first‐pass perfusion CT: locating transplanted cells relative to infarcted myocardial targets

A challenge with cardiac cell therapy is determining the location of cells relative to infarct tissue. As cells are viable following ¹¹¹In-labeling, and first-pass CT imaging can identify regions of myocardial infarction, we evaluated the feasibility of a SPECT/CT system to localize cells relative to infarcted myocardium in a canine model. Ten canines underwent surgical ligation of the left-anterior-descending artery and endothelial progenitor cells labeled with ¹¹¹In-tropolone were transplanted endocardially or epicardially. SPECT/CT was performed on day of transplantation, 4 and 10 days post-transplantation. For each imaging session first-pass perfusion CT was performed to delineate the area of reduced perfusion. SPECT and first-pass CT images were fused and evaluated. Contrast-to-noise ratios (CNR) were calculated for ¹¹¹In-SPECT images to evaluate cell detection. The zone of reduced perfusion was well delineated on first-pass perfusion CT in all canines. The ¹¹¹In signal was visualized within this zone in all cases. Analysis of the CNRs suggests that cells may be followed for 11 effective half-lives using the images from first-pass perfusion CT to provide the anatomic landmarks. In the setting of an acute myocardial infarction SPECT/[first-pass perfusion CT] is an effective hybrid platform for the localization of cells in relation to the area of reduced blood flow.

Contrast Evaluation for a Dual Head SPECT System with Different Energy PeakingDrift

Gamma cameras contain energy discriminators that allow only those photons within a specified energy range to be recorded. The process of setting this energy window is called “peaking” the camera. A spontaneous shift in the peak of one head of a triple-head gamma camera was reported to cause an artifact that mimicked ischemia on 201Tl-chloride myocardial SPECT. The characteristic energy distribution results from the collection of total photon energy absorbed by the detector. Physically peaked detectors will center the energy window on the photo peak of selected isotope. Aim of the study: Our aim is to evaluate the effect of energy peak drifting for both imaging heads on the image contrast in SPECT. Materials and methods: Using a dual head gamma camera, the SPECT phantom with its inserts was scanned using a fixed acquisition protocol and image reconstruction parameters but with changing the energy peak window adjustment which was operated for both heads at different values starting from 120 KeV up to 160 KeV with incremental step of 5 KeV, and the window width was adjusted to be 15% as used in the clinical applications.Results: Our results shows a fluctuation in the image contrast, as there was a gradual increase in the contrast value from 120 KeV setting up to 140 KeV by 31 % and also there was a gradual decrease in the contrast value from 140 KeV setting up to 160 KeV setting by 15 %. The clinical verification for these results was done on cardiac patient who underwent a cardiac scan twice with the normal gamma camera peak setting and then with off-peak setting at 120 KeV (which gives the lowest contrast value for the phantom study). And the case interpretation results confirm the phantom results as there was a significant change in the uptake in the left ventricle wall, with also a verification from the quantitative results by the Quantitave comparison using the quantitative gated SPECT data, that shows a 9% difference in the EF calculated value from the normal to the off-peak setting, which may affect the interpretation and in consequence the further treatment of the patient.Conclusion: The energy window peaking for the gamma camera has a proven effect on the planar images, and this was explained and proved in our study to have a significant effect on the contrast of the SPECT images which will affect the interpretation of the clinical results.

A randomised, double-blind and placebo-controlled study of the extracorporeal cardiac shock wave therapy for coronary artery disease

ObjectiveTo evaluate the feasibility, security and efficiency of extracorporeal cardiac shock wave therapy (CSWT) for treatment of coronary artery disease.MethodsA total of 25 patients with old myocardial infarction (OMI without...

Assessment of left ventricular contractile reserve by means of myocardial perfusion-gated SPECT in patients with early systolic dysfunction after acute myocardial infarction and in patients with chronic ischemic cardiomyopathy

In patients with depressed systolic function after recent acute myocardial infarction (AMI), improvement of global left ventricular (LV) systolic function using low-dose dobutamine (LDD) may be influenced by factors different from those observed in patients with chronic ischemic cardiomyopathy (CIC). The aim of this study was to analyze, by means of myocardial perfusion-gated single photon emission computed tomography, segmental thickening (STh), LV volumes and ejection fraction (EF), at baseline and during LDD infusion in patients with systolic dysfunction early after AMI, and compare these results with those in patients with CIC. Prospective, multicenter study. Eighty-nine patients {mean 60.7 years [standard deviation (SD)=12.9]} with coronary artery disease and LVEF less than or equal to 40% were investigated with resting gated single photon emission computed tomography with LDD, 41 patients between 5 and 8 days post-AMI, and 48 patients with CIC. Post-AMI the patients had lower LVEF, worse STh scores, and a greater number of segments with severely diminished thickening than patients with CIC. In post-AMI patients, contractile reserve in segments with severely impaired baseline thickening was predictive of a more than or equal to 5% increase in LVEF [odds ratio (OR): 3.77], whereas in patients with CIC the predictors were global contractile reserve (OR: 2.45) and a lower resting end-diastolic volume (OR: 0.98). Improvement of LVEF with LDD in patients with systolic dysfunction early after AMI depended essentially on contractile reserve in segments with severely impaired baseline thickening, whereas in patients with CIC it depended on overall LV contractile reserve and the presence of less ventricular remodeling.

Patients with left bundle branch block pattern and high cardiac risk myocardial SPECT: does the current management suffice?

Myocardial perfusion SPECT (MPS) is frequently used for cardiovascular risk stratification. The significance of MPS in patients with abnormal electrical ventricular activation is often questionable. This review assesses the value of MPS for risk stratification of patients with intrinsic left bundle branch block or that due to right ventricular apical pacing. We reviewed the literature by a search of the MEDLINE database (January 1980 to September 2010). The terms prognosis or prognostic value were combined with SPECT and LBBB or pacing or pacemakers. MPS was categorised as low and high risk according to the original definitions. We identified 11 studies suitable for review. A low-risk MPS is associated with a low risk of cardiac events whereas high-risk MPS carries a 4.8-fold increased risk, 95% CI [3.2 - 7.2] (p < 0.0001). Despite secondary prevention and an improved medical and interventional care, these figures have hardly changed over time. A low-risk MPS permits a policy of watchful waiting whereas a high-risk MPS requires further analysis and treatment. The persistent high cardiac death and acute myocardial infarction rate after a high-risk MPS suggest that the current management of these patients does not suffice and needs reconsideration.

SHA 004. Diagnostic valve of nitrate enhanced Tc-99m sestamibi gated myocardial spect in myocardial viability: Prospective analysis

ically indicated CCT. Methods: All patients were scanned using retrospective gating on a 64-slice CCT, for clinically indicated reasons, where coronary CT angiogram and calcium score measurements were performed. The amount of radiation was calculated from different parameters in millisievert (mSv). Results: 1287 patients were scanned with mean age of 52 ± 13.2 y, 65% males, and 35% females. Chest pain was the indication in 80% of cases. There mean radiation dose was 15 ± 10.4 (mSv). Patients with body mass index (BMI) P 35 received more radiation compared to those with BMI < 30 was, 15.3 ± 9.3 vs. 14.6 ± 7.4 (mSv), p< 0.002. Patients who had coronary bypass surgery (CABG) received significantly higher dose of radiation, 22.2 ± 9.3 vs. 14.4 ± 10.4 (mSv), P < 0.0001. Conclusion: Overweight patients and patients who underwent CABG are exposed to significantly higher radiation dose during CCT. Measures have to be applied to minimize the radiation dose during CCT.

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

025 Validation of a “low dose thallium 201 protocol” with a cadmium-zinc-telluride (CZT) cardiac camera

Thallium 201 is the most efficient radiotracer for myocardial perfusion imaging but leads to relative high radiation exposure for patients. We used a new cardiac CZT camera to decrease the effective dose with thallium-201 in myocardial perfusion imaging. We prospectively studied 137 consecutive patients referred for stress myocardial perfusion imaging and who previously had in the last 5 years a myocardial SPECT with thallium-201. We injected at stress a low dose of thallium 201 (1 to 1.2 MBq/kg, i.e. 74 MBq for 70 kgs), performed stress myocardial imaging in 5 to 7 mn with a CZT camera GE Discovery NM 530c and redistribution imaging when initial images were abnormal, with reinjection (37 MBq) when previous myocardial infarction or severe defect or without reinjection in other cases. We compared the CZT scan with the scan previously performed in the last 5 years with conventional dual head tomographic Anger camera (CC) with a regular dose of thallium-201. Patients had known coronary artery diseases in 85% of cases, myocardial scar in 38% and ischemia in 20%. The average stress dose was 88 MBq versus 125 MBq previously (−30%) The average time for camera acquisition was 6 mn versus 13 mn (−54%) The cardiac counts statistic was higher with CZT (>1 Mcts) By comparison with CC, the quality of CZT images was better (better delineation of left ventricular cavity, visualization of papillary muscles, easier thickening analysis) in 70% of cases, equal in 24% and worse in 6% (6 artefacts, 2 digestive contaminations) Comparison of artefacts showed 30 unmodified, 29 less and 6 additionnal artefacts. By comparison with the previous SPECT, we missed no pathological image; furthermore, we detected 5 true pathological images which were missed with the CC. Calculated effective dose was less than 12 mSv when no reinjection and less than 18 mSv when reinjection. With reduced activities of thallium 201 (−30%) and effective doses between 12 and 18 mSv, CZT camera gives reliable high quality imaging

093 Ability of ST/HR index and ST/HR hysteresis during exercise testing to predict significant ischemia assessed by G-SPECT imaging

Heart rate adjustment of exercise-induced ST-segment depression (ST/HR index and ST/HR hysteresis) has been suggested as an accurate predictor of the presence of a coronary artery disease. Its powerful predictive value for proven coronary artery stenosis is now accepted. The objective of our study was to investigate the sentitivity and specificity of computerized ST/HR index and ST/HR hysteresis to detect significant ischemia. We used a cross-sectional analysis of exercise test and myocardial perfusion stress-rest SPECT data. The study population comprised 710 consecutive patients referred for myocardial perfusion imaging. The threshold of significant ischemia was set above 10% reversibility hypoperfusion area from entire surface of left ventricle using gated-SPECT image analysis (QGS). Diagnostic performance of ST/HR index and ST/HR hysteresis was assessed by receiver operating characteristic (ROC) curve. Crude ST/HR hysteresis showed at the same 70% specificity, a sensitivities of 56% and 57%, respectively. Diagnostic performance of ST/HR hysteresis seems slightly better than ST/HR index (AUC = .668 vs .654) with the following cut points .038 mV and 1.625 μV/bpm. Adjusting these variables to body mass index does not improve the diagnostic performance. Combining an independant clinical judgement in the model yields a moderate increase of the diagnostic accuracy the prediction only for ST/HR index as suggested by the AUC (.688). ST/HR index and ST/HR hysteresis have a good capability to detect a significant myocardial ischemia evaluated by SPECT, which has therapeutic implications.

064 The role of ST/HR index and ST/HR hysteresis in detection of significant ischemia in patients referred for a dipyridamol SPECT imaging

The capability ST/HR index and ST/HR hysteresis in detection of ischemia has been validated in patients undergoing standard exercise testing. Its predictive value has never been assessed in pharmacological stress tests using adenosine or dipyridamol. The objective of our study was to compare the sensitivity and the specificity of ST/HR index and ST/HR hysteresis regarding the diagnostic capability of significant ischemia in patients undergoing stress test with dipirydamol for SPECT evaluation. We used a cross-sectional analysis of ST/HR index myocardial perfusion stress-rest SPECT data. Two hundred eighty consecutive patients referred for SPECT evaluation and unable to perform a standard exercise test underwent a pharmacological stress test with dipirydamol. The threshold of significant ischemia was set above 10% reversibility hypoperfusion area from entire surface of left ventricle using semi-quantitative SPECT image analysis (QGS). Diagnostic performance of computerized variables was assessed by receiver operating characteristic (ROC) curve. Area under ROC curve for ST/HR index and ST/HR hysteresis were 0.564 and 0.597. Sensitivities were 38% and 36%, respectively, when specificity was set at 73% for this parameter. The cut points for ST/HR index and ST/HR hysteresis at this same specificity were 1.05 μV/(beats/min) and 0.015 mV, respectively. Whereas ST/HR index and ST/HR hysteresis are useful to detect exercise-induced ischemia, these variables don’t have a good capability in detection of significant ischemia in a population of patients who are tested with dipirydamol despite an acceptabe specificity.

心筋ＳＰＥＣＴ画像におけるコリメータ開口補正の基礎的検討

The purpose of this study was to evaluate the effect of myocardial perfusion imaging that is reconstructed using the ordered subsets-expectation maximization (OS-EM) method with collimator broad correction. A cardiac phantom and clinical data (with ten normal patients) were used. These projection data were reconstructed using OS-EM with collimator broad correction (OS-EM(+)), without collimator broad correction (OS-EM(-)), and with filtered back projection (FBP). We analyzed the reconstructed images using the following: FWHM of reoriented short-axis data, volume calculated using QGS software, and a polar map calculated using QPS software. On the important point of spatial resolution, OS-EM(+) was excellent compared with FBP. However, a difference in % uptake was seen in one segment. Therefore, when a quantitative myocardial SPECT evaluation is done, the treatment of the numerical value needs to be noted.

The Usefulness of Treatment Evaluation of Severe Heart Failure by ECG-gated Myocardial SPECT

The Usefulness of Treatment Evaluation of Severe Heart Failure by ECG-gated Myocardial SPECT

New software for raw data mask processing increases diagnostic ability of myocardial SPECT imaging

Increased activity of myocardial perfusion tracer technetium-99m in liver and hepatobiliary system causes streak artifacts, which may affect clinical diagnosis. We developed a mask-processing tool for raw data generated using technetium-99m as a myocardial perfusion tracer. Here, we describe improvements in image quality under the influence of artifacts caused by high accumulation in other organs. A heart phantom (RH-2) containing 15 MBq of pertechnetate was defined as model A. Model B was designed in the same phantom containing ten times of cardiac radioactivity overlapping with other organs. Variance in the vertical profile count in the lower part of the myocardial inferior wall and in the myocardial circumferential profile curve were investigated in a phantom and clinical cases using our raw data masking (RDM) software. The profile variances at lower parts of myocardial inferior walls were 965.43 in model A, 1390.11 in model B and 815.85 in B-RDM. The mean ± SD of myocardial circumferential profile curves were 83.91 ± 7.39 in model A, 69.61 ± 11.45 in model B and 82.68 ± 9.71 in model B-RDM. For 11 clinical images with streak artifacts, the average of the variance significantly differed between with and without RDM (3.95 vs. 21.05; P < 0.05). For 50 clinical images with hepatic accumulation artifacts, the average of the variance on vertical profiles on images with and without RDM significantly differed (5.99 vs. 15.59; P < 0.01). Furthermore, when a segment with <60% uptake in polar maps was defined as abnormal, the average extent score of 1 h (Tc-1h), 5 min of RDM (Tc-0h-RDM) and 5 min of non-RDM (Tc-0h-non-RDM) were 2.25 ± 3.12, 2.35 ± 3.16, and 1.37 ± 2.41, respectively. Differences were significant between Tc-1h and Tc-0h-non-RDM (P < 0.005) but not between Tc-1h and Tc-0h-RDM. Batch processing was enabled in all frames by shifting the myocardium to the center of rotation using this software. The waiting time between infusion and image acquisition should be decreased, thus reducing patient burden and improving the diagnostic ability of the procedure.

Myocardial perfusion imaging using a technetium-99m Sestamibi in asymptomatic and low risk for coronary artery disease patients with diagnosed systemic lupus erythematosus

The aim of the present study was to evaluate technetium-99m sestamibi single photon emission tomography (SPECT) myocardial perfusion imaging (MPI) and its association with some clinical and laboratory parameters in an asymptomatic systemic lupus erythematosus (SLE) population. Twenty-one subjects with SLE and no suspected or documented coronary artery disease (CAD) accomplished myocardial perfusion imaging. Some SLE and CAD parameters were also evaluated in association with myocardial SPECT. Twenty-one women with a diagnosis of SLE (mean age 36.9 ± 12.8) entered the study. All patients were in the low-risk category for CAD pretest; however, abnormal myocardial perfusion results were found in eight (38%) patients. Amongst the traditional CAD risk factors, there was a significant association between the presence of dyslipidemia and myocardial perfusion abnormalities (P= 0.047). However, we found no significant association between other traditional and SLE-specific risk factors. This study's significant finding was that asymptomatic CAD is common in SLE patients, even in those thought to be low risk for CAD and in the absence of cardiac symptoms.