Myocardial perfusion imaging with 13N-ammonia PET is a strong predictor for outcome.

BACKGROUND/OBJECTIVES: The aim of the present study was to assess the long-term predictive value of myocardial perfusion imaging (MPI) with (13)N-ammonia positron emission tomography (PET) in patients with suspected myocardial perfusion abnormality. At present, outcome data on the predictive value of MPI in (13)N-ammonia PET exist only for rather small patient populations. METHODS: Cardiac perfusion was assessed in 943 consecutive patients using (13)N-ammonia PET, and follow-up was obtained in 698 (74%). 77 patients who underwent early revascularization (<60 days) were excluded and 621 patients were assigned to normal versus abnormal perfusion for outcome analysis. Hard events (cardiac death and non-fatal myocardial infarction) and major adverse cardiac events (MACE; hard events, hospitalization for cardiac reasons and late revascularization) were investigated using the Kaplan-Meier method. Independent predictors for various cardiac events were identified using Cox proportional hazard regression analysis. RESULTS: During follow-up (5.7 ± 2.5 years), 275 patients had at least 1 cardiac event, including 102 cardiac deaths and 33 non-fatal myocardial infarction. Abnormal perfusion (n=469) was associated with a higher incidence of MACE (P<0.001) and hard events (P<0.001) throughout the 10-year follow-up period. CONCLUSIONS: Cardiac perfusion findings in (13)N-ammonia PET are strong predictors of long-term outcome.

Diagnostic value of 13N-ammonia myocardial perfusion PET: added value of myocardial flow reserve.

UNLABELLED: The ability to obtain quantitative values of flow and myocardial flow reserve (MFR) has been perceived as an important advantage of PET over conventional nuclear myocardial perfusion imaging (MPI). We evaluated the added diagnostic value of MFR over MPI alone as assessed with (13)N-ammonia and PET/CT to predict angiographic coronary artery disease (CAD). METHODS: Seventy-three patients underwent 1-d adenosine stress-rest (13)N-ammonia PET/CT MPI, and MFR was calculated. The added value of MFR as an adjunct to MPI for predicting CAD (luminal narrowing ≥ 50%) was evaluated using invasive coronary angiography as a standard of reference. RESULTS: Per patient, the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of MPI for detecting significant CAD were 79%, 80%, 91%, 59%, and 79%, respectively. Adding a cutoff of less than 2.0 for global MFR to MPI findings improved the values to 96% (P < 0.005), 80%, 93%, 89% (P < 0.005), and 92% (P < 0.005), respectively. CONCLUSION: The quantification of MFR in (13)N-ammonia PET/CT MPI provides a substantial added diagnostic value for detection of CAD. Particularly in patients with normal MPI results, quantification of MFR helps to unmask clinically significant CAD.

Image quality and radiation dose comparison of prospectively triggered low-dose CCTA: 128-slice dual-source high-pitch spiral versus 64-slice single-source sequential acquisition.

Currently 64-multislice computed tomography (MSCT) scanners are the most widely used devices allowing low radiation dose coronary CT angiography (CCTA) with prospective ECG triggering. Latest 128-slice dual-source CT (DSCT) scanners offer prospective high-pitch spiral acquisition covering the heart during one single beat. We compared radiation dose and image quality from prospective 64-MSCT versus high-pitch spiral 128-slice DSCT scanning, as such data is lacking. CCTA of 50 consecutive patients undergoing 128-DSCT (2 × 64 × 0.6 mm collimation, 0.28 s rotation time, 3.4 pitch, 100-120 kV tube voltage and 320 mAs tube current-time product) were compared to CCTA of 50 heart rate (HR) and BMI matched patients undergoing 64-MSCT (64 × 0.625 mm collimation, 0.35 s rotation time, 100-120 kV tube voltage and 400-650 mA tube current). Image quality was rated on a 4-point scale by two independent cardiac imaging physicians (1 = excellent to 4 = non-diagnostic). Of 710 coronary segments assessed on 128-DSCT, 216 (30.4%) achieved an image quality score 1 excellent, 400 (56.3%) score 2, 76 (10.7%) score 3 and 18 (2.6%) score 4 (non-diagnostic). Of 737 coronary segments evaluated on 64-MSCT 271 (36.8%) had an image quality score of 1, 327 (44.4%) 2, 110 (14.9%) score 3, and 29 (3.9%) segments score 4. Average image quality score for both scanners was similar (P = 0.641). The mean heart rate during scanning was 58.7 ± 5.6 bpm on 128-DSCT and 59.0 ± 5.6 bpm on 64-MSCT, respectively. Mean effective radiation dose was 1.0 ± 0.2 mSv for 128-DSCT and 1.7 ± 0.6 mSv for 64-MSCT (P < 0.001). 128-DSCT with high-pitch spiral mode allows CCTA acquisition with reduced radiation dose at maintained image quality compared to 64-MSCT.

Downstream resource utilization following hybrid cardiac imaging with an integrated cadmium-zinc-telluride/64-slice CT device.

PURPOSE: Low yield of invasive coronary angiography and unnecessary coronary interventions have been identified as key cost drivers in cardiology for evaluation of coronary artery disease (CAD). This has fuelled the search for noninvasive techniques providing comprehensive functional and anatomical information on coronary lesions. We have evaluated the impact of implementation of a novel hybrid cadmium-zinc-telluride (CZT)/64-slice CT camera into the daily clinical routine on downstream resource utilization. METHODS: Sixty-two patients with known or suspected CAD were referred for same-day single-session hybrid evaluation with CZT myocardial perfusion imaging (MPI) and coronary CT angiography (CCTA). Hybrid MPI/CCTA images from the integrated CZT/CT camera served for decision-making towards conservative versus invasive management. Based on the hybrid images patients were classified into those with and those without matched findings. Matched findings were defined as the combination of MPI defect with a stenosis by CCTA in the coronary artery subtending the respective territory. All patients with normal MPI and CCTA as well as those with isolated MPI or CCTA finding or combined but unmatched findings were categorized as "no match". RESULTS: All 23 patients with a matched finding underwent invasive coronary angiography and 21 (91%) were revascularized. Of the 39 patients with no match, 5 (13%, p < 0.001 vs matched) underwent catheterization and 3 (8%, p < 0.001 vs matched) were revascularized. CONCLUSION: Cardiac hybrid imaging in CAD evaluation has a profound impact on patient management and may contribute to optimal downstream resource utilization.

Impact of cardiac hybrid single-photon emission computed tomography/computed tomography imaging on choice of treatment strategy in coronary artery disease.

AIMS: Cardiac hybrid imaging by fusing single-photon emission computed tomography (SPECT) myocardial perfusion imaging with coronary computed tomography angiography (CCTA) provides important complementary diagnostic information for coronary artery disease (CAD) assessment. We aimed at assessing the impact of cardiac hybrid imaging on the choice of treatment strategy selection for CAD. METHODS AND RESULTS: Three hundred and eighteen consecutive patients underwent a 1 day stress/rest (99m)Tc-tetrofosmin SPECT and a CCTA on a separate scanner for evaluation of CAD. Patients were divided into one of the following three groups according to findings in the hybrid images obtained by fusing SPECT and CCTA: (i) matched finding of stenosis by CCTA and corresponding reversible SPECT defect; (ii) unmatched CCTA and SPECT finding; (iii) normal finding by both CCTA and SPECT. Follow-up was confined to the first 60 days after hybrid imaging as this allows best to assess treatment strategy decisions including the revascularization procedure triggered by its findings. Hybrid images revealed matched, unmatched, and normal findings in 51, 74, and 193 patients. The revascularization rate within 60 days was 41, 11, and 0% for matched, unmatched, and normal findings, respectively (P< 0.001 for all inter-group comparisons). CONCLUSION: Cardiac hybrid imaging with SPECT and CCTA provides an added clinical value for decision making with regard to treatment strategy for CAD.

Nuclear myocardial perfusion imaging with a novel cadmium-zinc-telluride detector SPECT/CT device: first validation versus invasive coronary angiography.

PURPOSE: We evaluated the diagnostic accuracy of attenuation corrected nuclear myocardial perfusion imaging (MPI) with a novel hybrid single photon emission computed tomography (SPECT)/CT device consisting of an ultrafast dedicated cardiac gamma camera with cadmium-zinc-telluride (CZT) solid-state semiconductor detectors integrated onto a multislice CT scanner to detect coronary artery disease (CAD). Invasive coronary angiography served as the standard of reference. METHODS: The study population included 66 patients (79% men; mean age 63 ± 11 years) who underwent 1-day (99m)Tc-tetrofosmin pharmacological stress/rest examination and angiography within 3 months. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) as well as accuracy of the CT X-ray based attenuation corrected CZT MPI for detection of CAD (≥ 50% luminal narrowing) was calculated on a per-patient basis. RESULTS: The prevalence of angiographic CAD in the study population was 82%. Sensitivity, specificity, PPV, NPV and accuracy were 87, 67, 92, 53 and 83%, respectively. CONCLUSION: In this first report on CZT SPECT/CT MPI comparison versus angiography we confirm a high accuracy for detection of angiographically documented CAD.

Main pulmonary artery diameter from attenuation correction CT scans in cardiac SPECT accurately predicts pulmonary hypertension.

OBJECTIVES: To establish the value of the main pulmonary artery (MPA) diameter assessed from unenhanced computer tomography (CT) scans used for attenuation correction (AC) of single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) to predict pulmonary hypertension (PHT). BACKGROUND: In contrast-enhanced chest CT scans an MPA diameter of 29 mm or greater is an established predictor of PHT. However, it is unknown, whether measurements from an unenhanced CT scan for AC may be used as predictor of PHT. METHODS: 100 patients underwent SPECT MPI for assessment of coronary artery disease. PHT was defined as a right ventriculo-atrial gradient of 30 mm Hg or greater by Doppler echocardiography. We compared MPA diameter from CT to SPECT findings (right ventricular hypertrophy/enlargement, septal wall motion abnormality/perfusion defect, and D-shape) to determine the best predictor of PHT. RESULTS: PHT was found in 37 patients. An MPA diameter of 30 mm or greater yielded a sensitivity, specificity, accuracy, positive, and negative predictive value of 78%, 91%, 86%, 83%, and 88%, respectively. This yielded an area under the ROC curve of 0.85. CONCLUSIONS: MPA diameter from low-dose unenhanced multi-slice CT reliably predicts PHT, providing an important added clinical value from AC for SPECT MPI.

Inter-scan variability of coronary artery calcium scoring assessed on 64-multidetector computed tomography vs. dual-source computed tomography: a head-to-head comparison.

AIMS: Coronary artery calcium (CAC) scoring has emerged as a tool for risk stratification and potentially for monitoring response to risk factor modification. Therefore, repeat measurements should provide robust results and low inter-scanner variability for allowing meaningful comparison. The purpose of this study was to investigate inter-scanner variability of CAC for Agatston, volume, and mass scores by head-to-head comparison using two different cardiac computed tomography scanners: 64-detector multislice CT (MSCT) and 64-slice dual-source CT (DSCT). METHODS AND RESULTS: Thirty patients underwent CAC measurements on both 64-MSCT (GE LightSpeed XT scanner: 120 kV, 70 mAs, 2.5 mm slices) and 64-DSCT (Siemens Somatom Definition: 120 kV, 80 mAs, 3 mm slices) within <100 days (0-97). Retrospective intra-scan comparison revealed an excellent correlation. The excellent intra-scan (inter-observer) agreement was documented by narrow limits of agreement and a correlation coefficient of variation (COV) of r ≥ 0.99 (P < 0.001) for all CAC scores with a low COV for both scanners (64-MSCT/64-DSCT), i.e. Agatston (2.0/2.1%), mass (3.0/2.0%), and volume (4.7/3.9%). Inter-scanner comparison revealed larger Bland-Altman (BA) limits of agreement, despite high correlation (r ≥ 0.97) for all scores, with COV at 15.1, 21.6, and 44.9% for Agatston, mass, and volume scores. The largest BA limits were observed for volume scores (-1552.8 to 574.2), which was massively improved (-241.0 to 300.4, COV 11.5%) after reanalysing the 64-DSCT scans (Siemens) with GE software/workstation (while Siemens software/workstation does not allow cross-vendor analysis). Phantom measurements confirmed overestimation of volume scores by 'syngo Ca-Scoring' (Siemens) software which should therefore be reviewed (vendor has been notified). CONCLUSION: Intra- and inter-scan agreement of CAC measurement in a given data set is excellent. Inter-scanner variability is reasonable, particularly for Agatston units in the clinically most relevant range <1000. The use of different software solutions has a greater influence particularly on volume scores than the use of different scanner types.

Very high coronary calcium score unmasks obstructive coronary artery disease in patients with normal SPECT MPI.

OBJECTIVES: To study the clinical impact of a very high coronary artery calcium score (CAC >1000) in patients with no known coronary artery disease (CAD) and normal single photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI). The secondary aim was to evaluate whether triple vessel disease would support the notion of balanced ischaemia as an underlying mechanism of false negative SPECT MPI in patients with very high CAC. BACKGROUND: No data exist on the clinical value of high CAC in patients with normal SPECT MPI. METHODS: 50 patients with suspected CAD and normal stress/rest SPECT MPI and CAC >1000 prospectively underwent invasive coronary angiography as the standard of reference. Coronary lesions with ≥50% luminal diameter narrowing on invasive coronary angiography were considered to represent significant stenosis. RESULTS: The median total CAC was 1975 (range 1018-8046). In 37/50 (74%) patients, coronary angiography revealed one-vessel disease (1-VD) (n=15), 2-VD (n=10) or 3-VD (n=12). Twenty-six revascularisations (percutaneous coronary intervention/coronary artery bypass grafting) were performed in seven (6/1), seven (6/1) and 12 (7/5) patients with 1-VD, 2-VD and 3-VD, respectively. CONCLUSIONS: In patients with normal SPECT MPI, a CAC >1000 confers a high diagnostic added value for detecting CAD. This is not solely based on unmasking balanced ischaemia due to epicardial 3-VD, as it occurred predominantly in patients with 1-VD and 2-VD.

Prognostic value of cardiac hybrid imaging integrating single-photon emission computed tomography with coronary computed tomography angiography.

Aims Although cardiac hybrid imaging, fusing single-photon emission computed tomography (SPECT) myocardial perfusion imaging with coronary computed tomography angiography (CCTA), provides important complementary diagnostic information for coronary artery disease (CAD) assessment, no prognostic data exist on the predictive value of cardiac hybrid imaging. Hence, the aim of this study was to assess the prognostic value of hybrid SPECT/CCTA images. Methods and results Of 335 consecutive patients undergoing a 1-day stress/rest (99m)Tc-tetrofosmin SPECT and a CCTA, acquired on stand-alone scanners and fused to obtain cardiac hybrid images, follow-up was obtained in 324 patients (97%). Survival free of all-cause death or non-fatal myocardial infarction (MI) and free of major adverse cardiac events (MACE: death, MI, unstable angina requiring hospitalization, coronary revascularizations) was determined using the Kaplan-Meier method for the following groups: (i) stenosis by CCTA and matching reversible SPECT defect; (ii) unmatched CCTA and SPECT finding; and (iii) normal finding by CCTA and SPECT. Cox's proportional hazard regression was used to identify independent predictors for cardiac events. At a median follow-up of 2.8 years (25th-75th percentile: 1.9-3.6), 69 MACE occurred in 47 patients, including 20 death/MI. A corresponding matched hybrid image finding was associated with a significantly higher death/MI incidence (P < 0.005) and proved to be an independent predictor for MACE. The annual death/MI rate was 6.0, 2.8, and 1.3% for patients with matched, unmatched, and normal findings. Conclusion Cardiac hybrid imaging allows risk stratification in patients with known or suspected CAD. A matched defect on hybrid image is a strong predictor of MACE.

Improved outcome prediction by SPECT myocardial perfusion imaging after CT attenuation correction.

UNLABELLED: The aim of this study was to determine the impact of attenuation correction with CT (CT-AC) on the prognostic value of SPECT myocardial perfusion imaging (SPECT MPI). METHODS: The summed stress score (SSS; 20-segment model) was obtained from filtered backprojection (FBP) and iterative reconstruction with CT-AC in 876 consecutive patients undergoing a 1-d stress-rest (99m)Tc-tetrofosmin SPECT MPI study for the evaluation of known or suspected coronary artery disease. Survival free of major adverse cardiac events (MACEs; cardiac death or nonfatal myocardial infarction) and survival free of any adverse cardiac events (including cardiac hospitalization, unstable angina, and late coronary revascularization) were analyzed by Kaplan-Meier analysis. RESULTS: At a mean follow-up of 2.3 ± 0.6 y, a total of 184 adverse events occurred in 145 patients, including 35 MACEs (16 cardiac deaths [rate, 1.8%] and 19 nonfatal myocardial infarctions [rate, 2.2%]). With FBP, an SSS of 0-3 best distinguished patients with a low MACE rate (0.6%), followed by an SSS of 4-8 (4.3%), with increased MACE rate, and an SSS of 9-13 (3.8%), which was comparable. By contrast, with CT-AC the discrimination of low from intermediate MACE rate was best observed between an SSS of 0 (0%) and an SSS of 1-3 (3.7%), with a plateau at an SSS of 4-8 (3.2%). CONCLUSION: CT-AC for SPECT MPI allows improved risk stratification. The prognostically relevant SSS cutoff is shifted toward lower values.

Rapid cardiac hybrid imaging with minimized radiation dose for accurate non-invasive assessment of ischemic coronary artery disease.

BACKGROUND: Ischemic coronary artery disease (CAD) is a major cause for morbidity and mortality resulting in a continuously increasing number of diagnostic interventions. We have validated a new hybrid imaging method using minimized radiation dose for rapid non-invasive prediction of invasive coronary angiography (CA) findings with regard to coronary lesion detection and revascularization. METHODS: Forty patients referred for elective invasive coronary angiography (CA) due to suspected CAD were prospectively enrolled to undergo a low-dose CTCA with prospective ECG-triggering and a stress-only SPECT-MPI scan administering half of the standard low-dose stress (99m)Tc-tetrofosmin activity. The latter was acquired immediately after adenosine stress (omitting the standard 30-60 min waiting time). After fusing CTCA and SPECT-MPI decisions towards conservative management versus revascularization strategy based on hybrid images were compared to the decisions taken by the interventional operator in the catheterization laboratory based on CA. The latter served as standard of reference. RESULTS: Hybrid images yielded sensitivity, specificity, positive and negative predictive values and accuracy of 100%, 96.0%, 100%, 93.8% and 97.5% for predicting coronary revascularization. The estimated mean effective radiation doses were significantly lower for hybrid imaging (4.7 ± 1.0 mSv) than for invasive CA (8.7 ± 4.2 mSv; P<0.001 vs. hybrid). Total non-invasive protocol time was below 60 min, comparing favourably to standard SPECT protocols. CONCLUSIONS: Rapid cardiac hybrid imaging allows accurate prediction of invasive CA findings and of treatment decision despite minimized radiation dose and protocol time.

Long-term prognostic value of left ventricular dyssynchrony assessment by phase analysis from myocardial perfusion imaging.

OBJECTIVE: To assess the value of left ventricular (LV) dyssynchrony, using phase analysis of nuclear single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) as independent predictor of cardiac events. METHODS: Phase analysis using Emory Cardiac Toolbox was applied on gated rest MPI scans to assess LV dyssynchrony in a total of 202 patients. Follow-up was obtained in 197 patients (97.5%). Major adverse cardiac events (MACE) (cardiac death and hospitalisation for any cardiac reasons, including worsening of heart failure, non-fatal myocardial infarction, unstable angina and coronary revascularisation) were determined using the Kaplan-Meier method. Cox proportional hazard regression was used to identify independent predictors of cardiac events. RESULTS: At a median follow-up of 3.2 ± 1.2 years, 41 patients had at least one event, including 5 cardiac deaths. LV dyssynchrony (n = 35) was associated with a significantly higher incidence of MACE (p<0.001) and proved to be an independent predictor of cardiac events. CONCLUSION: LV dyssynchrony assessed by phase analysis of gated SPECT-MPI is a strong predictor of MACE independent of other known predictors such as perfusion defects or decreased LV ejection fraction.

Validation of CT attenuation correction for high-speed myocardial perfusion imaging using a novel cadmium-zinc-telluride detector technique.

UNLABELLED: The aim of this study was to validate attenuation correction (AC) using low-dose standard CT for myocardial perfusion imaging (MPI) on a novel ultra fast γ-camera with cadmium-zinc-telluride (CZT) detector technology. METHODS: Sixty-six patients (body mass index ± SD, 27.2 ± 3.5 kg/m(2); range, 19.1-36.0 kg/m(2)) underwent a 1-d (99m)Tc-tetrofosmin adenosine stress-rest imaging protocol with 15-min acquisitions on a standard dual-head SPECT camera. All scans were repeated within minutes on the CZT camera, with 3-min acquisitions for stress (low dose) and 2-min acquisitions for rest (high dose) as recently established. We compared maximum myocardial uptake (20-segment model) from CZT versus standard SPECT MPI by intraclass correlation without and with CT AC. In addition, clinical agreement for each coronary territory for all scans from both devices was assessed, and Bland-Altmann (BA) limits of agreement for percentage uptake were calculated. RESULTS: The clinical agreement between CZT and standard SPECT cameras was 96% for noncorrected low- and high-dose images (r = 0.90 and BA = -18 to 15, and r = 0.91 and BA = -15 to 16, respectively), and agreement after AC was 96% for low- and 99% for high-dose images (r = 0.87 and BA = -16 to 14, and r = 0.88 and BA = -16 to 14, respectively). CONCLUSION: Our results support that AC of MPI on the novel CZT camera, compared with AC MPI on a conventional SPECT camera, is feasible because it provides a high correlation of segmental tracer uptake and an excellent clinical agreement.

Real-time breath-hold triggering of myocardial perfusion imaging with a novel cadmium-zinc-telluride detector gamma camera.

PURPOSE: The aim of this study was to assess the ability of real-time breath-hold-triggered myocardial perfusion imaging (MPI) using a novel cadmium-zinc-telluride (CZT) gamma camera to discriminate artefacts from true perfusion defects. METHODS: A group of 40 patients underwent a 1-day (99m)Tc-tetrofosmin pharmacological stress/rest imaging protocol on a conventional dual detector SPECT gamma camera with and without attenuation correction (AC), immediately followed by scanning on an ultrafast CZT camera with and without real-time breath-hold triggering (instead of AC) by intermittent scanning confined to breath-hold at deep inspiration (using list mode acquisition). We studied the use of breath-hold triggering on the CZT camera and its ability to discriminate artefacts from true perfusion defects using AC SPECT MPI as the reference standard. Myocardial tracer uptake (percent of maximum) from CZT was compared to AC SPECT MPI by intraclass correlation and by calculating Bland-Altman limits of agreement. RESULTS: AC of SPECT MPI identified 19 apparent perfusion defects as artefacts. Of these, 13 were correctly identified and 4 were partially unmasked (decrease in extent and/or severity) by breath-hold triggering of the CZT scan. All perfusion defects verified by SPECT MPI with AC were appropriately documented by CZT with and without breath-hold triggering. This was supported by the quantitative analysis, as the correlation (r) of myocardial tracer uptake between CZT and AC SPECT improved significantly from 0.81 to 0.90 (p<0.001) when applying breath-hold triggering. Similarly, Bland-Altman limits of agreement were narrower for CZT scans with breath-hold triggering. CONCLUSION: This novel CZT camera allows real-time breath-hold triggering as a potential alternative to AC to assist in the discrimination of artefacts from true perfusion defects.

Ultrafast assessment of left ventricular dyssynchrony from nuclear myocardial perfusion imaging on a new high-speed gamma camera.

PURPOSE: To validate the ultrafast assessment of left ventricular (LV) dyssynchrony by phase analysis using high-speed nuclear myocardial perfusion imaging (MPI) on a new gamma camera with cadmium-zinc-telluride (CZT) solid-state detector technology. METHODS: In 46 patients rest MPI with 960 MBq (99m)Tc-tetrofosmin was acquired on a dual-head detector SPECT camera (Ventri, GE Healthcare) and an ultrafast CZT camera (Discovery NM 530c, GE Healthcare) with acquisition times of 15 and 5 min, respectively. LV dyssynchrony was assessed using the Emory Cardiac Toolbox with established values for histogram bandwidth (male <62.4°; female <49.7°) and standard deviations (male <24.4°; female <22.1°) as the gold standard. Evaluating CZT scan times of 0.5, 1, 2, 3 and 5 min (list mode) in 16 patients revealed the preferred scan time to be 5 min, which was then applied in all 46 patients. Intraclass correlation and the level of agreement in dyssynchrony detection between the CZT and Ventri cameras were assessed. RESULTS: In LV dyssynchrony the mean histogram bandwidths with the CZT camera (n = 8) and the Ventri camera (n = 9) were 123.3 ± 50.6° and 130.2 ± 43.2° (p not significant) and 42.4 ± 13.6° vs. 43.2 ± 12.7° (p not significant). Normal bandwidths and SD obtained with the CZT camera (35.9 ± 7.7°, 12.6 ± 3.5°) and the Ventri camera (34.8 ± 6.6°, 11.1 ± 2.1°, both p not significant) excluded dyssynchrony in 38 and 37 patients, respectively. Intraclass correlation and the level of agreement between the CZT camera with a 5-min scan time and the Ventri camera were 0.94 (p < 0.001, SEE 14.4) and 96% for histogram bandwidth and 0.96 (p < 0.001, SEE 3.9) and 98% for SD. CONCLUSION: This ultrafast CZT camera allows accurate assessment of LV dyssynchrony with a scan time of only 5 min, facilitating repeat measurements which would potentially be helpful for parameter optimization for cardiac resynchronization therapy.