MPI Studies Research Articles

Effect of gender on spect myocardial perfusion imaging results in Egypt

BackgroundGlobally, Ischemic heart disease (IHD) is considered a leading cause of mortality and morbidity affecting men than women. The more the population ages, the more the prevalence. There was a concern about improper referral of women to MPI testing. We aimed to study if there a gender effect on the results of MPI studies and if this could have an impact on future referral or investigation selection for diagnosis of IHD as a general or specially in women.ResultsFemale gender represented 266 (60%) while male represented in 177 (40%). Males demonstrated significantly higher age (55 ± 10 vs. 49 ± 9, P < .0001), weight (85 ± 11 vs. 83 ± 13, P = 0.006), height (166 ± 4 vs. 165 ± 4, P = 0.02), and smoking (35% vs. 0%, P < 0.001) than females. Male gender was associated with ten times increased risk of positive MPI (OR = 10, 95% CI = 5.348–18.868, P < 0.001). Diabetes was associated with an increased risk of positive MPI (OR = 1.82, 95% CI = 1.052–3.148, P = 0.032).ConclusionsPositive MPI test are more common in males. Female patients with positive MPI were younger in age than male patients. Diabetes mellitus and age are traditional strong predictors for the presence of positive MPI test.

Artificial intelligence approach improves ischaemia prediction beyond the known pretest probability scores

Abstract Background Pre-test probability (PTP) assessment is crucial in the assessment of patients with suspected ischaemia/coronary artery disease. Presently there is no established role for artificial intelligence in estimating PTP. Purpose Comparison of a recently developed memetic pattern based algorithm (MPA) with the diagnostic power of established scores in predicting ischaemia on positron emission tomography myocardial perfusion imaging (PET MPI). Methods Consecutive patients undergoing Rubidium PET MPI for routine clinical evaluation of ischaemia were included. The PTP for each patient was estimated by MPA, the Diamond and Forrester scores (DFS), the PTP models from the European Society of Cardiology Guidelines from 2013 (ESC 2013) and 2019 (ESC 2019) and the Framingham scores (FRS). The PET MPI studies were assessed for the presence of ischaemia. Ischaemia was defined as a summed difference score (SDS) ≥2. Results The mean age of the 531 patients was 66±11 years, 34% were female, and 50% had known prior coronary artery disease; 208 patients had evidence of ischaemia. No ischaemia was found in 323 patients. The areas under the curve (AUC) are shown in the figure. The artificial intelligence based MPA provided an AUC of 0.76, PTP (ESC 2013) AUC of 0.67, PTP (ESC 2019) AUC 0.67, DFS AUC 0.56, FRS 0.68. Conclusion The MPA outperforms the established scores for PTP assessment of the ESC, DFS and FRS in prediction of ischaemia on PET MPI. It has the potential to improve the accuracy of the established diagnostic algorithm for CAD and ischaemia. Funding Acknowledgement Type of funding sources: Public grant(s) – National budget only. Main funding source(s): The study was in part funded by the Swiss Heart Foundation.

ASSESSMENT OF MYOCARDIAL VIABILITY USING LOW DOSE DOBUTAMINE THREE DIMENSIONAL SPECKLE TRACKING STRESS TRANSTHORACIC ECHOCARDIOGRAPHY

Background: Three-dimensional speckle tracking echocardiography (3D STE) is used recently to assess many cardiac diseases; it is considered as natural growth of two-dimensional speckle tracking echocardiography (2D STE). The LV mechanics is in nature a 3D phenomenon and its accurate assessment requires a 3D imaging method. 3DSTE has been implemented for measuring 3D strain, and has emerged as a more physiologically sound tool for analyzing the complexity of LV mechanics, overcoming the inherent limitations of 2D STE. Objective: To determine the relative accuracy of area strain measured by 3D speckle-tracking echocardiography combined with low dose dobutamine for the detection of myocardial viability before coronary revascularization in comparison with MPI. Patients and Methods: The study included 40 patients referred to Bab El-She’riya University Hospital nuclear lab for assessment of myocardial viability by MPI before coronary revascularization. Then all patients were referred to Islamic Cardiac Center Echo lab where complete conventional transthoracic echocardiography was done followed by Low dose dobutamine (LDD) stress transthoracic echocardiography with 3D STE then comparing results of 3D strain of viable segments with that of nonviable segments and with corresponding segments in MPI studies. Results: The study showed that 241 segments in the 40 patients were assigned as abnormal segments, 114 were viable and 127 were nonviable, resting area strain (AS)was -18.7±2.5 for viable segments comparing to -12.6±5.3 for non-viable segment. A cut-off point of -16 was chosen to differentiate viable segments from non-viable ones with sensitivity 80.75% and specificity 83.1%. The average LDD AS value for viable segments was-24.5±2.7 and was -15.2±4.8 of non-viable segments with a cut-off point of -24 to differentiate viable segments from non-viable ones with sensitivity of 84.75% and a specificity of 89.1%. The average increase of AS of viable segments after LDD was -5.8±2.3 with a cut-off point to detect viability was a -0.24 increase in LDD from resting AS with a sensitivity of 95.75% and a specificity of 98.1%. Conclusion: AS obtained from 3D STE may be used clinically as an indicator to detect myocardial viability with higher sensitivity and specificity when combined with LDD.

Long-Term Prognostic Value of Appropriate Myocardial Perfusion Imaging

Appropriate use criteria (AUC) for single-photon emission computed tomography myocardial perfusion images (SPECT-MPIs) were developed to address the growth of cardiac imaging studies. Long-term prognostic value of AUC in SPECT-MPI has not been tested in existing cohorts. We sought to determine the long-term prognostic value of MPI classified as appropriate. AUC was evaluated in a prospectively designed cohort of patients who underwent clinically indicated MPI. MPI studies were classified based on 2009 AUC for SPECT-MPI. Data regarding downstream coronary angiography (cath), revascularization and all-cause mortality, cardiac death, and nonfatal myocardial infarction (MI) were collected from national registries. Among n= 1,129 MPI scans that received an appropriate grading, 148 all-cause deaths, 109 MIs, 58 cardiac deaths, 152 caths, 113 revascularization procedures occurred over a mean follow-up period of 5.4 ± 1.2years (0.9% cardiac death rate per year, 1.8% MI rate per year). Most of the scans were low-risk normal MPI scans (summed stress score ≤3; 74.1%). An abnormal scan was associated with higher rates of MI (19.5% vs 6.2%, hazard ratio 1.72, p= 0.017) and cardiac death (13.4% vs 2.3%, hazard ratio 2.12, p= 0.016). In conclusion, MPI scans classified as appropriate have long-term prognostic value, despite a high proportion of low-risk scans. This provides support for clinicians to consider the use of appropriate grading in addition to MPI scan results in patient management.

Diagnostic Invasive Coronary Angiography in Patients with Small Myocardial Perfusion Defects with Low Exercise Tolerance

Background: The diagnostic and prognostic value of stress myocardial perfusion scintigraphy is well established in literature. The sensitivity and specificity of the test depends on multiple factors. The workload achieved during treadmill exercise is one of the most important determinants. Hence, we thought to assess the coronary anatomy in a group of patients with low exercise tolerance that showed small perfusion defects on stress MPI studies. Material and methods: We prospectively enrolled 50 patients with mild perfusion defects and a poor exercise tolerance. An invasive coronary angiography was done according to the clinical decision of the treating physician. All patients were subjected to full history and clinical examination. Stress SPECT Tc99m Sestamibi scintigraphy was done on basis of a 2 day stress/rest imaging protocol (Exercise duration, age predicted maximal heart rate (APMHR %), ejection fraction (EF%), transient ischemic dilatation and duke treadmill score(DTS)) were recorded. A coronary stenosis ≥ 75% was considered significant. In the current study, APMHR 0.05 is considered significant. Results: Among the study cohort, a total of 6 patients (12%) had significant CAD. In presence of a small perfusion defect in the setting of low exercise tolerance, significant CAD was observed more frequently in patients with exercise duration ≤ 7 min, APMHR <85%, transient stress induced LV cavity dilatation and moderate/high DTS. The six patients with significant angiographic lesions demonstrated single vessel disease in the whole group. Distribution of the angiographic lesions was as follows: RCA (4 patients) 66.7%, the LAD (one patient) 16.65%, and the LCX (one patient) 16.65%. Conclusion: In the setting of low exercise tolerance, negative MPI/small sized perfusion defect may not exclude significant CAD. Several clinical, stress, and SPECT-MPI findings may help to predict high risk patients. Consideration of these factors may improve the overall assessment of the likelihood of significant CAD in patients undergoing stress SPECT- MPI.

“Same-patient processing” for multiple cardiac SPECT studies. 2. Improving quantification repeatability

ObjectivesThis paper investigates the ability of grouped quantification (an expression of the same-patient processing approach, or SPP) to improve repeatability of measurements in patients with multiple SPECT studies, and evaluates its performance compared to standard quantification in a population of 100 patients undergoing rest, stress, gated rest, and gated stress SPECT MPI. All acquisitions were performed twice, back-to-back, for a total of 800 image datasets (8 per patient). MethodsEach dataset was automatically processed (a) independently, using standard quantitative software, and (b) as a group, together with the other 7 datasets belonging to the same patient, using an SPP-modified version of the software that registered the images to one another using a downhill simplex algorithm for the search of optimal translation, rotation, and scaling parameters. ResultsOverall, grouped quantification resulted in significantly lower differences between repeated measurements of stress ungated volumes (1.40 ± 2.76 mL vs 3.33 ± 5.06 mL, P < .05), end-diastolic volumes (1.78 ± 2.78 vs 3.49 ± 5.35 mL, P < .05), end-systolic volumes (1.17 ± 1.96 vs 2.44 ± 3.35 mL, P < .05), and LVEFs (−0.45 ± 2.29% vs −1.16 ± 3.30%, P < .05). Additionally, grouped quantification produced better repeatability (lower repeatability coefficients) for stress and rest ungated volumes (5.4 vs 9.9 and 5.2 vs 13.1, respectively), stress TPD (2.6 vs 3.6), stress and rest end-diastolic volumes (5.5 vs 10.5 and 7.2 vs 14.7, respectively), stress and rest end-systolic volumes (3.8 vs 6.6 and 5.3 vs 10.3, respectively), stress and rest LVEFs (4.5 vs 6.5 and 4.7 vs 8.2, respectively), and rest total motion deficit (5.6 vs 9.6). ConclusionIt is possible to improve the repeatability of quantitative measurements of parameters of myocardial perfusion and function derived from SPECT MPI studies of a same patient by group processing of image datasets belonging to that patient. This application of the same-patient processing approach is an extension of the “paired processing” technique already described by our group, and can be performed in automated fashion through incorporation in the quantitative algorithm.

Outcomes after inappropriate nuclear myocardial perfusion imaging: A meta-analysis

BackgroundThe relationship between inappropriate MPI and cardiovascular outcomes is poorly understood. We sought to systematically review the literature on appropriate use criteria (AUC) for MPI, including temporal trend of inappropriate testing and resulting cardiovascular outcomes. MethodsWe searched the MEDLINE database for studies related to AUC and MPI. The co-primary outcomes were abnormal test results and the presence of cardiac ischemia. Random effects odds ratios (OR) were constructed using DerSimonian-Laird method. ResultsA total of 22 studies with 23,443 patients were included. The prevalence of inappropriate testing was 14.8% [95% confidence interval (CI) 11.6%-18.7%]. Inappropriate MPI studies were less likely to be abnormal (OR 0.41 95% CI 0.35-0.49, P < .0001) and to demonstrate ischemia (OR 0.40, 95% CI 0.24-0.67, P < .0001) compared to appropriate testing. No difference in the rate of inappropriate tests was detected based on the midpoint of the enrollment year (P = .54). The pattern of ordering inappropriate studies was not different between cardiology and non-cardiology providers (OR 0.74, 95% CI 0.51-1.06, P = .10). ConclusionInappropriate MPI studies are less likely to yield abnormal results or demonstrate myocardial ischemia. The rate of inappropriate MPI has not decreased over time.

The Clinical Dilemma of Incidental Findings on the Low-Resolution CT Images from SPECT/CT MPI Studies.

Incidental findings are common in medical imaging. There is a particularly high prevalence of incidental findings within the thorax, the most frequent being pulmonary nodules. Although pulmonary nodules have the potential to be malignant, most are benign, resulting in a high number of false-positive findings. Low-resolution CT images produced for attenuation correction of SPECT images are essentially a by-product of the imaging process. The high number of false-positive incidental findings detected on these attenuation-correction images causes a reporting dilemma. Early detection of cancer can be beneficial, but false-positive findings and overdiagnosis can be detrimental to the patient. Attenuation-correction CT images are not of diagnostic quality, and further diagnostic tests are usually necessary for a definitive diagnosis to be reached. Given the high number of false-positive findings, the psychologic effect on the patient should be considered. This review recommends caution when the findings on attenuation-correction CT images are routinely reported.

Increased accuracy of single photon emission computed tomography (SPECT) myocardial perfusion scintigraphy using iterative reconstruction of images.

Filtered back projection (FBP) is a common way of processing myocardial perfusion imaging (MPI)studies. There are artifacts in FBP which can cause false-positive results. Iterative reconstruction (IR) is developed to reduce false positive findings in MPI studies. The aim of this study was to evaluate the difference in the number of false-positive findings in MPI studies, between FBP and IR processing. We examined 107 patients with angina pectoris with MPI and coronary angiography (CAG), 77 man and 30 woman, aged 32-82. MPI studies were processed with FBP and with IR. Positive finding at MPI was visualization of the perfusion defect. Positive finding at CAG was stenosis of coronary artery. Perfusion defect at MPI without coronary artery stenosis at CAG was considered like false positive. The results were statistically analyzed with bivariate correlation, and with one sample t-test. There were 20.6% normal, and 79.4% pathologic findings at FBP, 30.8% normal and 69.2% pathologic with IR and 37.4% normal and 62.6% pathologic at CAG. FBP produced 19 false positive findings, at IR 11 false positive findings. The correlation between FBP and CAG was 0.658 (P < 0.01) and between IR and CAG 0.784 (P < 0.01). The number of false positive findings at MPI with IR was significantly lower than at FBP (p < 0.01). Our study shows that IR processing MPI scintigraphy has less number of false positive findings, therefore it is our choice for processing MPI studies.

Influence of respiratory motion correction on quantification of myocardial perfusion SPECT

BackgroundRespiratory-related cardiac motion could have considerable effects on myocardial perfusion imaging, leading to misinterpretation of the images. In this study, we examined the influence of respiratory correction on ECG-gated myocardial perfusion SPECT (RC-GSPECT) concerning regional myocardial perfusion and function. Materials and MethodsUsing the NCAT phantom, a typical torso phantom was generated. SimSET, a Monte Carlo simulator, was used to image the photon emerging from the phantom. Twenty-six patients underwent a 2-day stress-rest ECG-gated myocardial perfusion SPECT (GSPECT) imaging. A separate study was also performed by simultaneous respiratory and cardiac triggering with the real-time position management (RPM) for respiratory correction (RC). ResultsIn simulation study, count density in the inferior and inferoseptal walls increased in the lower bin of the respiratory cycle. On the other hand, there was a higher correlation between RC-GSPECT and echocardiography for left ventricular ejection fraction (LVEF) (r = 0.95, P < .01 vs r = 0.88, P < .01 for GSPECT). ConclusionWe proposed a new approach for respiratory and cardiac-gated SPECT to eliminate respiratory motion artifacts. RC-GSPECT is a feasible method in MPI studies and may play an important role to improve the quality of MPI images, particularly in the inferior wall.

Quantitative interpretation of FDG PET/CT with myocardial perfusion imaging increases diagnostic information in the evaluation of cardiac sarcoidosis

BackgroundFDG PET/CT with myocardial perfusion imaging is a useful method for evaluating cardiac sarcoidosis (CS), but interpretation is not standardized. We developed a method for quantification of cardiac FDG PET/CT and evaluated its relationship to conventional interpretation, perfusion defects, clinical events, and immunosuppressive treatment. Methods and ResultsFDG PET/CT with MPI studies performed for CS (n = 38) were retrospectively compared to negative control studies acquired for oncologic indications (n = 10). Quantitative measures of FDG volume-intensity (Cardiac Metabolic Activity, CMA) was performed using standardized uptake values (SUVs). CMA (477.7 ± 909 vs 0.55 ± 2.1 vs 0.3 ± 0.3 g glucose, P = .02) was significantly greater in visually FDG-positive studies compared to visually negative and oncologic negative studies. Among patients with CS, CMA was greater in studies with an EF < 50% (760.3 ± 1,148 vs 87.4 ± 161 g glucose, P = .03) and preceding an adverse clinical event (1,095 ± 1,253 vs 73 ± 144 g glucose, P = .006). CMA was the only independent predictor of events by multivariate analysis. In patients with repeat examinations (n = 7), CMA decreased with prednisone treatment in 5 of 6 patients. ConclusionsQuantification of FDG uptake in CS correlates with lower EFs, clinical events, and immunosuppression treatment.

Inappropriate utilization of SPECT myocardial perfusion imaging on the USA-Mexico border

BackgroundThe American College of Cardiology/American Society of Nuclear Cardiology published revised appropriate use criteria (AUC) for SPECT MPI in 2009. We assessed adherence to these guidelines and factors associated with inappropriate utilization at the University Medical Center. MethodsThe AUC was applied retrospectively to 420 SPECT MPI studies. Two-sample t test, Fisher’s exact test, and multivariable logistic regression models were used for analysis. ResultsThere were 322 appropriate (86%) and 54 (14%) inappropriate studies. The odds of having an inappropriate test increased with younger age (P < .001) and female gender (P < .001). Subjects with diabetes (P = .007) and chest pain (P < .001) were less likely to have an inappropriate test. Academic outpatients were three times more likely to have an inappropriate study (P = .123), while community PCPs were 5.6 times (P = .011) and community cardiologists eight times more likely to order inappropriate tests (P = .031). ConclusionsInappropriate SPECT MPI in low risk younger women is an important issue on the USA-Mexico border. Initiatives to reduce inappropriate SPECT MPI should focus on a few indications and evaluation of cardiovascular symptoms in younger age women in outpatient/community practices.

Risk stratification using line source attenuation correction with rest/stress Tc-99m sestamibi SPECT myocardial perfusion imaging

BackgroundAlthough line source attenuation correction (AC) in SPECT MPI studies improves diagnostic accuracy, its prognostic value is less understood. MethodsConsecutive patients (n = 6,513) who underwent rest/stress AC ECG-gated SPECT MPI were followed for cardiac death or non-fatal myocardial infarction (MI). A 17-segment model and AC summed stress score (SSS) were used to classify images. ResultsOf the 6,513 patients, cardiac death or non-fatal MI occurred in 267 (4.1%), over 2.0 ± 1.4 years. The AC-SSS in patients with a cardiac event (5.6 ± 7.8) was significantly higher than in those without (1.9 ± 4.6, P < .001). The annualized cardiac event rate in patients with an AC-SSS 1-3 (3.6%) was significantly higher than in those with an AC-SSS = 0 (1.1%, P < .001) but similar to that in those with an AC-SSS 4-8 (2.9%, P = .4). Accordingly, patients were classified to AC-SSS = 0, 1-8, and >8 with annualized cardiac event rates of 1.1%, 3.2%, and 8.5%, respectively (P < .0001). In multivariate analysis, an AC-SSS 1-8 and >8 emerged as independent predictors of cardiac events (P < .02 and P < .0001, respectively). ConclusionRest/stress ECG-gated SPECT MPI with line source AC provides highly effective and incremental risk stratification for future cardiac events.

Utilization Patterns of Single‐Photon Emission Cardiac Tomography Myocardial Perfusion Imaging Studies in a Rural Tertiary Care Setting

Appropriate use criteria (AUC) for single-photon emission computed tomographic myocardial perfusion imaging (SPECT MPI) were revised in 2009 to include 15 new clinical scenarios. We assessed multivariable predictors and overall appropriateness of MPI studies performed in a rural tertiary care setting. We hypothesized that appropriate utilization rates of SPECT MPI imaging in a rural tertiary care center are similar for cardiology and non cardiology providers. We reviewed all SPECT MPI studies performed for over a 6-month period at our center. Using 67 scenarios in AUC, we categorized these studies as appropriate, inappropriate, uncertain, or unclassifiable. Of 328 MPI studies, 287 (88%) studies were classified as appropriate, 18 (5.5%) as inappropriate, 23 (7%) as uncertain, and none as unclassifiable. Preoperative testing accounted for 44% of the inappropriate studies; 61% of uncertain tests were ordered for cardiovascular risk assessment in patients with prior normal coronary angiography or normal stress tests. The ordering provider specialty did not show any relation with appropriateness of the test (P = 0.46). Patients with inappropriate and uncertain studies were younger than patients with appropriate studies (P = 0.007). We found that a majority of MPI studies are performed for appropriate indications regardless of ordering provider specialty. Few common scenarios accounted for the majority of the inappropriate or uncertain studies.

High-efficiency SPECT MPI: Comparison of automated quantification, visual interpretation, and coronary angiography

BackgroundRecently introduced high-efficiency (HE) SPECT cameras with solid-state CZT detectors have been shown to decrease imaging time and reduce radiation exposure to patients. An automated, computer-derived quantification of HE MPI has been shown to correlate well with coronary angiography on one HE SPECT camera system (D-SPECT), but has not been compared to visual interpretation on any of the HE SPECT platforms. MethodsPatients undergoing a clinically indicated Tc-99m sestamibi HE SPECT (GE Discovery 530c with supine and prone imaging) study over a 1-year period followed by a coronary angiogram within 2 months were included. Only patients with a history of CABG surgery were excluded. Both MPI studies and coronary angiograms were reinterpreted by blinded readers. One hundred and twenty two very low (risk of CAD < 5%) or low (risk of CAD < 10%) likelihood subjects with normal myocardial perfusion were used to create normal reference limits. Computer-derived quantification of the total perfusion deficit at stress and rest was obtained with QPS software. The visual and automated MPI quantification were compared to coronary angiography (≥70% luminal stenosis) by receiver operating curve (ROC) analysis. ResultsOf the 3,111 patients who underwent HE SPECT over a 1-year period, 160 patients qualified for the correlation study (66% male, 52% with a history of CAD). The ROC area under the curve (AUC) was similar for both the automated and the visual interpretations using both supine only and combined supine and prone images (0.69-0.74). Using thresholds determined from sensitivity and specificity curves, the automated reads showed higher specificity (59%-67% vs 27%-60%) and lower sensitivity (71%-72% vs 79%-93%) than the visual reads. By including prone images sensitivity decreased slightly but specificity increased for both. By excluding patients with known CAD and cardiomyopathies, AUC and specificity increased for both techniques (0.72-0.82). The use of a difference score to evaluate ischemic burden resulted in lower sensitivities but higher specificities for both automated and visual quantification. There was good agreement between the visual interpretation and automated quantification in the entire cohort of 160 unselected consecutive patients (r = 0.70-0.81, P < .0001). ConclusionsAutomated and visual quantification of high-efficiency SPECT MPI with the GE Discovery camera provides similar overall diagnostic accuracy when compared to coronary angiography. There was good correlation between the two methods of assessment. Combined supine and prone stress imaging provided the best diagnostic accuracy.

Stress-only imaging in patients with prior SPECT MPI: A simulation study

The aim of this study was to determine if omitting the repeat resting scan in patients who had prior single-photon emission computed tomography myocardial perfusion imaging (SPECT MPI) would have an impact on the interpretation of the stress test. Current guidelines recommend stress and rest imaging for SPECT MPI studies. Stress-only imaging has also entered the guidelines as a feasible option in low-risk patients but has not been studied in high-risk patients. Two independent readers interpreted 47 consecutive MPIs with prior images to determine if the repeat resting scan had an impact on interpretation of the stress test images. In this retrospective analysis, we compared interpretation of stress-only SPECT images using the old rest image for comparison versus conventional rest-stress SPECT imaging. Both readers were blinded to study results. The primary end point of this study was a comparison of summed difference scores (SDS) from stress-only interpretation compared to standard rest-stress interpretation. In this study, 36% (98/272) of patients had previous SPECT MPI. Of these patients, 48% (n = 47) were eligible for stress-only imaging. There was strong agreement between the SDS from the new stress versus old rest image compared with the new stress versus new rest image (r = 0.866, P < .001) with a mean difference in SDS of 0.6 ± 1.7. In this population, 41 of the 47 studies (87%) could have been performed with a stress-only SPECT MPI with comparison with the prior resting study. Starting with the stress-only protocol would have reduced the radiation in this population by 76%. Very similar data is obtained with stress-only imaging in patients who have a prior resting study. Our study suggests that the stress-only imaging may possibly be expanded to populations who have been studied previously or are at higher risk, reserving the option to add a resting study if the interpretation of the stress-only study is unclear.

Abstract 17551: The Impact of Ordering Provider Specialty on Appropriateness Classification

The Impact of Ordering Provider Specialty on Appropriateness Classification In prior studies, our laboratory applied the ACCF/ASNC AUC for SPECT MPI to several cohorts of patients in Mayo Clinic Rochester. The purpose of this study was to re-examine our data to test the hypothesis that the specialty of the ordering provider affected the appropriateness. We compared the ordering providers specialty with appropriateness determined in prior studies. The study group consisted of 281 patients who underwent stress SPECT MPI studies in May 2005 and 282 patients in October 2006 (before any quality improvement initiatives were begun at Mayo). Appropriateness categories were assigned by 2 experienced nurses from the CV Research Studies Unit not affiliated with the nuclear laboratory. Patients who were studied for pre-operative evaluation (n = 20) or post myocardial infarction (n = 7) were excluded because they comprised less than 5 percent of the patients. Pre-operative testing in our institution is done primarily by stress echocardiography. The final study group consisted of 526 patients. Excluding the 64 unclassified patients, AUE categories were appropriate (75 %), uncertain (13 %), inappropriate (12%). Results by ordering provider are shown in the figure, where CV = Cardiovascular MDs, ED = Emergency Department MDs, IM = General and Internal Medicine MDs, RN = Registered Nurses, and SP = other Specialty MDs. There was no significant association (p = 0.19); Chi-square analysis between appropriateness and specialty groups. In a clinical practice where pre-operative testing using SPECT is infrequent, the rate of inappropriate studies was similar for all ordering providers. Quality improvement efforts in similar practices will likely require a broad focus on all ordering physicians/nurses.

Stress-only or stress/rest myocardial perfusion imaging in patients undergoing evaluation for bariatric surgery

BackgroundBariatric surgery for management of obesity is being used with increasing frequency. Stress testing with myocardial perfusion imaging is often employed as part of the workup prior to anticipated bariatric surgery. The incidence of clinically significant abnormalities on stress MPI performed for this indication, however, has not been established. Methods and ResultsWe retrospectively reviewed a series of 383 consecutive stress MPI studies performed on patients undergoing workup prior to planned bariatric surgery. The study population had a mean age 42 ± 10 years, and was 83% female, with a body mass index of 49 ± 8. The majority of patients (81%) were able to exercise using either the Bruce or Modified Bruce protocol, and 67% underwent stress-only imaging. Overall SPECT MPI findings were normal in 89% and equivocal in 6% of patients. The incidence of abnormal findings on MPI was 5% (3% mild and 2% moderate-to-severe abnormalities). At 1 year, overall survival was 99.5%, with no difference between those with and without MPI abnormalities. Similarly, the incidence of post-operative cardiac events was very low (2%), and mostly due to atrial arrhythmias or borderline elevations of troponin. ConclusionIn a typical pre-bariatric surgery population, the incidence of abnormal stress MPI is low. The majority of patients were able to use a stress-only strategy for assessment of perfusion. At 1 year the incidence of adverse cardiovascular outcomes is very low. Additional studies should be focused on determining whether any subgroup of such patients may benefit more from pre-operative stress testing.

Evaluation of the American College of Cardiology Foundation/American Society of Nuclear Cardiology appropriateness criteria for SPECT myocardial perfusion imaging in an Asian tertiary cardiac center

BackgroundAppropriate use criteria (AUC) for SPECT MPI have been published to address concern about the growth of cardiac imaging studies and the effective use of imaging, but there is no published data on its role outside the United States. MethodsAll consecutive patients referred to the MPI laboratory of our center from February 16 to June 19, 2009 were prospectively studied. Patients’ medical records and stress data were collected and all imaging results were recorded. Based on AUC, MPI studies were classified into appropriate, inappropriate, uncertain, or unclassified. MPI studies were classified on the basis of their results into normal or abnormal scans. ResultsThere were 1,623 patients (mean age 61 years ± 11, 61% males). Most common indications for SPECT were evaluation of ischemic equivalent for coronary artery disease (CAD), risk assessment post-revascularization, and preoperative evaluation for non-cardiac surgery. 10% of referrals were classified as inappropriate, 5% uncertain, and 3% unclassified. Women (48.4% vs 40.6% for men, P = .063) and asymptomatic patients (50.2% vs 14.3% for symptomatic, P < .001) had a higher proportion of inappropriate studies. The preoperative group had the highest proportion of inappropriate studies (59%). Appropriate referrals had a higher proportion of abnormal SPECT results than inappropriate referrals (40% vs 27%, OR 2.08, 95% CI 1.56-2.77, P < .001). ConclusionsThe pattern of referrals for SPECT MPI in an Asian center appears to vary from published reports in the United States. Preoperative evaluation for low-risk surgery appears to be the most common source of inappropriate referrals in our institution. Inappropriate referrals have a higher proportion of normal studies, but 27% were still reported as abnormal.

Assessing the Prognostic Value of Cardiovascular Imaging

Cardiovascular imaging has become the focus of attention from both physicians and payers. The former see the potential of newer modalities to permit new and exciting insights into the diagnosis and management of coronary artery disease (CAD), that, in turn, may result in enhanced patient care strategies and new efficient clinical algorithms. On the other hand, payers have understandable concerns about the excessive use and enormous costs associated with cardiovascular imaging. These concerns have been exacerbated by the rapid expansion of the imaging devices used for the assessment of patients with known or suspected CAD. Cardiovascular stress imaging has long been the domain of stress single photon emission computed tomography myocardial perfusion imaging (SPECT MPI) and stress echocardiography wall motion studies. At present, stress positron emission tomography (PET) MPI, cardiac computed tomography coronary angiography (CTA) (and, possibly, stress CT MPI), as well as cardiac magnetic resonance imaging (CMR) MPI and wall motion studies are utilized in daily practice. Whether all of these modalities will be reimbursed in the future is uncertain, but little doubt remains that their rigorous validation will be compulsory. Article see p 1390 Cardiac magnetic resonance imaging is an evolving technique with growing indications within the clinical cardiology setting. Whereas late gadolinium enhancement (LGE) has gained acceptance as an accurate approach for viability assessment, CMR stress imaging use is increasing as well. Nonetheless, stress CMR techniques are in their relative infancy, and evidence is only now beginning to accumulate justifying their use. Whereas several studies have examined the diagnostic accuracy of stress CMR, only recently have sufficient numbers of patients been collected to assess the prognostic value of this approach1–5 (Table).6 The validation of stress CMR is more complex than that of previous modalities, inasmuch as a routine study would include rest function and …