ABSTRACT
PURPOSE: To compare the outputs of a novel all-purpose SPECT camera equipped with CZT detectors (Discovery NM/CT 670) with the state-of-the-art represented by a dedicated CZT (Alcyone, Discovery 530c) cardiac camera in patients submitted to myocardial perfusion imaging (MPI). METHODS: We included 19 patients that underwent sequential low-dose 99mTc-tetrofosmin (148-185 MBq during stress and 296-370 MBq at rest) MPI with Alcyone and Discovery 670 cameras. Quantitative (% tracer's uptake) and semi-quantitative analyses of perfusion data were performed for each scan. Moreover, major left ventricular (LV) functional and structural parameters were derived from each camera and compared. RESULTS: The two cameras showed excellent correlation for segmental myocardial % uptake at stress (R = 0.90; P < 0.001) and at rest (R = 0.88; P < 0.001) with narrow Bland-Altman limits of agreement. The level of diagnostic agreement of Discovery 670 and Alcyone cameras regarding perfusion analysis was excellent (Cohen's κ 0.85). Similarly, the two cameras showed excellent correlation in the evaluation of LV ejection fraction (R = 0.95), peak filling rate (R = 0.97), and mass (R = 0.98). CONCLUSIONS: Our preliminary results suggest that MPI with an all-purpose Discovery 670 CZT-SPECT camera is feasible, comparing well with the current state-of-the-art technology.
Subject(s)
Cadmium , Gamma Cameras , Heart Diseases/physiopathology , Myocardial Perfusion Imaging/instrumentation , Tellurium , Tomography, Emission-Computed, Single-Photon/instrumentation , Ventricular Function, Left/physiology , Zinc , Aged , Female , Heart Diseases/diagnostic imaging , Humans , Male , Middle Aged , Observer Variation , Reproducibility of Results , Stroke Volume/physiologyABSTRACT
BACKGROUND: Single-photon emission computed-tomography (SPECT) allows the quantification of LV eccentricity index (EI), a measure of cardiac remodeling. We sought to evaluate the feasibility of EI measurement with SPECT myocardial perfusion imaging and its interactions with relevant LV functional and structural parameters. METHODS AND RESULTS: Four-hundred and fifty-six patients underwent myocardial perfusion imaging on a Cadmium-Zinc-Telluride (CZT) camera. The summed rest, stress, and difference scores were calculated. From rest images, the LV end-diastolic (EDV) and end-systolic volumes, ejection fraction (EF), and peak filling rate (PFR) were calculated. In every patient, the EI, ranging from 0 (sphere) to 1 (line), was computed using a dedicated software (QGS/QPS; Cedars-Sinai Medical Center). Three-hundred and thirty-eight/456 (74%) patients showed a normal EF (>50%), while 26% had LV systolic dysfunction. The EI was computed from CZT images with excellent reproducibility (interclass correlation coefficient: 0.99, 95% CI 0.98-0.99). More impaired EI values correlated with the presence of a more abnormal LV perfusion (P < .001), function (EF and PFR, P < .001), and structure (EDV, P < .001). On multivariate analysis, higher EDV (P < .001) and depressed EF (P = .014) values were independent predictors of abnormal EI. CONCLUSIONS: The evaluation of LV eccentricity is feasible on gated CZT images. Abnormal EI associates with significant cardiac structural and functional abnormalities.
Subject(s)
Myocardial Perfusion Imaging , Tomography, Emission-Computed, Single-Photon , Ventricular Dysfunction, Left/diagnostic imaging , Ventricular Dysfunction, Left/physiopathology , Ventricular Remodeling/physiology , Aged , Aged, 80 and over , Cadmium , Feasibility Studies , Female , Humans , Male , Middle Aged , Reproducibility of Results , Stroke Volume/physiology , Tellurium , ZincABSTRACT
BACKGROUND: Myocardial perfusion imaging (MPI) performed on traditional single-photon emission computed-tomography cameras has been shown to have a sub-optimal accuracy in detecting multivessel coronary artery disease (CAD). METHODS: Six-hundred and ninety-five patients were submitted to MPI on a novel cadmium-zinc-telluride (CZT) camera and coronary angiography. A coronary stenosis >70% was considered obstructive. In every patient, the summed stress score (SSS) was computed. Moreover, the regional stress scores were also calculated for every coronary territory. RESULTS: Four-hundred and forty-one patients had obstructive CAD in one (28%), two (19%), or three (17%) vessels. At per-patient analysis, the SSS showed a significant accuracy in detecting obstructive CAD (AUC 0.87, P < .001). Specifically, its accuracy was maintained also in patients with double (AUC 0.83; P < .001) or triple-vessels disease (AUC 0.79, P < .001), where CZT was able to correctly identify CAD extent in 64% of patients. On a per-vessel basis, CZT confirmed its high accuracy in detecting obstructive CAD (AUC 0.88, P < .001), independently from the involved coronary vessel. CONCLUSIONS: MPI performed on a CZT camera is highly accurate in detecting obstructive CAD, independently from the coronary artery involved and the overall disease burden.
Subject(s)
Coronary Artery Disease/diagnostic imaging , Image Interpretation, Computer-Assisted/methods , Myocardial Perfusion Imaging/methods , Radionuclide Imaging/methods , Tomography, Emission-Computed, Single-Photon/methods , Aged , Cadmium , Female , Humans , Image Enhancement/methods , Male , Reproducibility of Results , Sensitivity and Specificity , Tellurium , ZincABSTRACT
PURPOSE: To evaluate the interplay between myocardial ischaemic burden and poststress left ventricular (LV) systolic and diastolic abnormalities in patients with suspected or known coronary artery disease (CAD). METHODS: A total of 471 patients underwent myocardial perfusion imaging by cadmium-zinc-telluride scintigraphy and coronary angiography. A fast imaging protocol was used with stress imaging performed 10 - 15 min after tracer injection. The summed difference score (SDS) and the percent stress-to-rest ratios for LV ejection fraction and peak filling rate (PFR), measures of stress-induced systolic and diastolic impairment, were computed from scintigraphic images. A SDS of >3 was considered abnormal and >7 a marker of moderate-to-severe ischaemia. RESULTS: Of the 471 patients, 321 (68%) showed significant CAD in one (27%), two (23%) or three (18%) vessels. The extent of CAD associated with gradual alterations in SDS (P < 0.001). Interestingly, while impairment in the percent stress-to-rest PFR ratio paralleled the increase in the extent of CAD (P < 0.001 for trend), the occurrence of significant stress-induced systolic dysfunction was limited to patients with multivessel disease (P < 0.001 vs. patients without CAD, and P = 0.002 vs. patients with single-vessel disease). Similarly, while a strict correlation between percent stress-to-rest PFR ratio and myocardial ischaemic burden was evident (P < 0.001), significant stress-induced LV systolic impairment was limited to patients with moderate-to-severe ischaemia (P < 0.001 vs. patients with no or mild ischaemia). CONCLUSION: Stress-induced LV diastolic impairment is associated with a less extensive ischaemic burden and CAD extent than poststress systolic dysfunction, which is limited to patients with multivessel CAD.
Subject(s)
Cadmium , Coronary Artery Disease/diagnostic imaging , Myocardial Perfusion Imaging/methods , Tellurium , Ventricular Dysfunction, Left/diagnostic imaging , Zinc , Aged , Exercise Test , Female , Humans , Male , Middle Aged , Myocardial Perfusion Imaging/instrumentationABSTRACT
PURPOSE: To evaluate the relationships among myocardial sympathetic innervation, perfusion and mechanical synchronicity assessed with cardiac cadmium-zinc-telluride (CZT) scintigraphy. METHODS: A group of 29 patients underwent an evaluation of myocardial perfusion with (99m)Tc-tetrofosmin CZT scintigraphy and adrenergic innervation with (123)I-metaiodobenzylguanidine (MIBG) CZT scintigraphy. The summed rest score (SRS), motion score (SMS) and thickening score (STS), as well as the summed (123)I-MIBG defect score (SS-MIBG), were determined. Regional tracer uptake for both (99m)Tc-tetrofosmin and (123)I-MIBG was also calculated. Finally, the presence of significant myocardial mechanical dyssynchrony was evaluated in phase analysis on gated CZT images and the region of latest mechanical activation identified. RESULTS: Significant mechanical dyssynchrony was present in 17 patients (59 %) and associated with higher SRS (P = 0.030), SMS (P < 0.001), STS (P = 0.003) and early SS-MIBG (P = 0.037) as well as greater impairments in left ventricular ejection fraction (P < 0.001) and end-diastolic volume (P < 0.001). In multivariate analysis a higher end-diastolic volume remained the only predictor of mechanical dyssynchrony (P = 0.047). Interestingly, while in the whole population regional myocardial perfusion and adrenergic activity were strongly correlated (R = 0.68), in patients with mechanical dyssynchrony the region of latest mechanical activation was predicted only by greater impairment in regional (123)I-MIBG uptake (P = 0.012) that overwhelmed the effect of depressed regional perfusion. CONCLUSION: Left ventricular mechanical dyssynchrony is associated with greater depression in contractile function and greater impairments in regional myocardial perfusion and sympathetic activity. In patients with dyssynchrony, the region of latest mechanical activation is characterized by a significantly altered adrenergic tone.
Subject(s)
3-Iodobenzylguanidine , Cardiac-Gated Single-Photon Emission Computer-Assisted Tomography , Heart Ventricles/innervation , Myocardial Perfusion Imaging , Organophosphorus Compounds , Organotechnetium Compounds , Radiopharmaceuticals , Ventricular Dysfunction, Left/diagnostic imaging , 3-Iodobenzylguanidine/pharmacology , Aged , Cadmium , Female , Gamma Cameras , Heart Ventricles/physiopathology , Humans , Male , Middle Aged , Myocardial Contraction , Stroke Volume , Sympathetic Fibers, Postganglionic/drug effects , Sympathetic Fibers, Postganglionic/physiopathology , Tellurium , ZincABSTRACT
PURPOSE: In clinical myocardial single photon emission computed tomography (SPECT), attenuation artefacts may cause a loss of specificity in the identification of diseased vessels that can be corrected by means of gated SPECT (GSPECT) acquisition or CT attenuation correction (AC). The purpose of this multicentre study was to assess the impact of GSPECT and AC on the diagnostic performance of myocardial scintigraphy, according to patient's sex, body mass index (BMI) and site of coronary artery disease (CAD). METHODS: We studied a group of 104 patients who underwent coronary angiography within 1 month before or after the SPECT study. Patients with a BMI>27 were considered "overweight". Attenuation-corrected and standard GSPECT early images were randomly interpreted by three readers blinded to the clinical data. RESULTS: In the whole group, GSPECT and AC showed a diagnostic accuracy of 86.5% (sensitivity 82%, specificity 93%) and 77% (sensitivity 75.4%, specificity 81.4%), respectively (p<0.05). In women, when anterior ischaemia was matched with CAD, AC failed to show any increase in specificity (AC 63.6% vs GSPECT 63.6%) with evident loss of sensitivity (AC 72.7% vs GSPECT 90.9%). AC significantly improved SPECT specificity in the identification of right CAD in overweight men (AC 100% vs GSPECT 66.7%, p<0.05). CONCLUSION: AC improved specificity in the evaluation of right CAD in overweight men. In the other evaluable subgroups specificity was not significantly affected while sensitivity was frequently reduced.
Subject(s)
Artifacts , Cardiac-Gated Single-Photon Emission Computer-Assisted Tomography/methods , Image Processing, Computer-Assisted/methods , Myocardial Perfusion Imaging/methods , Adult , Aged , Aged, 80 and over , Body Mass Index , Coronary Artery Disease/diagnostic imaging , Coronary Artery Disease/physiopathology , Coronary Vessels/diagnostic imaging , Female , Humans , Male , Middle Aged , Sex Factors , Tomography, X-Ray ComputedABSTRACT
BACKGROUND: We previously demonstrated that early (15', T1) post-stress myocardial imaging with Tetrofosmin could be more accurate than standard acquisitions (45', T2) in identifying coronary artery disease. METHODS AND RESULTS: To clarify this phenomenon, 120 subjects (age 61 +/- 10 years) with both T1 and T2 scans were divided into Group 1 (53/120 pts) with more ischemia at T1 vs T2 imaging (T1-T2SDS > or = 3); Group 2 (67/120 pts) with similar results (T1-T2SDS < or = 2). Myocardial areas were categorized as control nonischemic, ischemic, and scarred on the basis of perfusion/contraction properties and coronary anatomy. In each area, regional myocardial count statistic and semiquantitative wall motion/thickening values were obtained. Analysis of T1 and T2 post-stress myocardial counts demonstrated a significant Tetrofosmin wash-out rate that was higher in Group 1 control nonischemic regions (15 +/- 8% vs 13.6 +/- 9.6%, P < .02), significantly lower in Group 1 ischemic regions (7 +/- 10% vs 12.2 +/- 9.5%, P < .0001), and comparable between scarred areas of the two groups (P = NS). Delta post-stress wall thickening (T1-T2) was lower in Group 1 ischemic regions (-4.5 +/- 9.15% vs -1.90 +/- 7.0%, P < .001) and comparable in both control nonischemic and scarred areas of the two groups (P = NS). CONCLUSION: The clinical result of Tetrofosmin gated-SPECT can be influenced by the post-stress acquisition time because of ischemic-induced regional wall thickening abnormalities and the existence of a differential radiotracer myocardial wash-out.
Subject(s)
Heart/diagnostic imaging , Myocardium/pathology , Organophosphorus Compounds , Organotechnetium Compounds , Radiopharmaceuticals , Tomography, Emission-Computed, Single-Photon/methods , Adult , Aged , Aged, 80 and over , Coronary Angiography , Coronary Artery Disease/diagnostic imaging , Coronary Artery Disease/pathology , Female , Humans , Male , Middle Aged , MotionABSTRACT
BACKGROUND: Tissue accumulation of misfolded transthyretin (TTR) may occur because of TTR gene mutations (variant amyloid TTR amyloidosis, ATTRv), or as an age-related phenomenon (wild-type ATTR, ATTRwt). Cardiac sympathetic denervation has been reported in ATTRv, but has never been investigated in ATTRwt. METHODS: Fifteen consecutive patients with ATTRwt cardiomyopathy (81% men, median age 82 years, no one with prior myocardial infarction) underwent Cadmium Zinc Telluride tomographic imaging for amyloid burden (99mTc-hydroxymethylene diphosphonate - 99mTc-HMDP), innervation (123I-metaiodobenzylguanidine - 123I-MIBG), and perfusion (99mTc-tetrofosmin). RESULTS: Median summed 99mTc-HMDP score was 60 (58-62), denoting a severe and diffuse amyloid burden. Planar 123I-MIBG examination showed decreased early and late H/M ratios (late H/M ratio: 1.5 [1.3-1.6], range 1.2-1.9, reference value ≥2.0). Summed 123I-MIBG score was 12 (6-22), with the most prominent denervation in the infero-septal, inferior, and infero-lateral regions; summed rest score was 7 (5-11), with lowest degrees of myocardial perfusion in the inferior and infero-septal regions. The correlation between amyloid burden (as relative 99mTc-HMDP uptake) and innervation (as relative 123I-MIBG uptake) did not achieve statistical significance at both segmental (p = .252) and regional level (p = .251). Nevertheless, denervation tended to worsen in parallel with the amyloid burden, and 123I-MIBG scores increased with 99mTc-HMDP scores. Segments and regions with prominent hypoperfusion also showed a higher degree of denervation (r = 0.500 and 0.591, respectively; both p < .001). CONCLUSIONS: Patients with ATTRwt cardiomyopathy display cardiac sympathetic denervation, particularly in the inferior and septal myocardial wall. Myocardial hypoperfusion has a similar regional pattern, while the amyloid burden is more extensive.
Subject(s)
Amyloid Neuropathies, Familial/pathology , Cardiomyopathies/pathology , Heart/innervation , Prealbumin/metabolism , Sympathectomy , Age Factors , Aged , Aged, 80 and over , Amyloid/metabolism , Amyloid Neuropathies, Familial/diagnostic imaging , Amyloid Neuropathies, Familial/genetics , Amyloid Neuropathies, Familial/metabolism , Cardiomyopathies/diagnostic imaging , Cardiomyopathies/genetics , Cardiomyopathies/metabolism , Female , Heart/diagnostic imaging , Humans , Male , Radiopharmaceuticals , Tomography, Emission-Computed/methodsABSTRACT
PURPOSE: To evaluate gender-related differences in diagnostic accuracy of cadmiumzinc-telluride (CZT) myocardial perfusion imaging in detecting single- and multi-vessel coronary artery disease (CAD). METHODS: We prospectively enrolled 1161 consecutive patients with known or suspected coronary artery disease (288, 25% women and 873, 75% men) who had been referred to our laboratory for stress-rest myocardial perfusion imaging (single-day stress-rest protocol, mean radiation dose: 4â¯mSv). All patients underwent coronary angiography within 30â¯days; significant CAD was defined in the presence of a coronary stenosis >70%. Summed stress scores (SSS), summed rest scores (SRS) and summed difference scores (SDS) were obtained. Image quality was graded "good" or better in >90% of patients. RESULTS: On coronary angiography, left main trunk, left anterior descending artery, left circumflex artery and right coronary artery obstructive stenosis were seen in 13, 486, 393 and 499 patients, respectively. Global SSS was the best predictor of CAD in women (AUCâ¯=â¯0.866, 81% sensitivity and 79% specificity) and in men (AUCâ¯=â¯0.871, 76% sensitivity and 84% specificity). Interestingly, its accuracy was maintained also in patients with two-vessel (women: AUCâ¯=â¯0.842, pâ¯<â¯0.001; men: AUC 0.839, pâ¯<â¯0.001) or three-vessel disease (women: AUCâ¯=â¯0.800, pâ¯<â¯0.001; men: AUC 0.804, pâ¯<â¯0.001). There was no gender-related difference in terms of diagnostic accuracy. CONCLUSIONS: Evaluation of multivessel disease can be obtained by CZT camera in men as well as in women, with high accuracy at a lower radiation exposure.
Subject(s)
Cadmium/pharmacology , Coronary Artery Disease/diagnosis , Coronary Vessels/diagnostic imaging , Tellurium/pharmacology , Tomography, Emission-Computed, Single-Photon/methods , Zinc/pharmacology , Aged , Coronary Artery Disease/epidemiology , Female , Follow-Up Studies , Humans , Incidence , Italy/epidemiology , Male , Myocardial Perfusion Imaging/methods , Prospective Studies , Reproducibility of Results , Sex FactorsABSTRACT
PURPOSE: The aim of the present study was to evaluate the expression of the cardiac norepinephrine transporter (NET) in the left ventricle (LV) of healthy pigs and its relationship with regional meta-[123I]iodobenzylguanidine ([123I]MIBG) myocardial uptake. PROCEDURES: Experiments were performed on animals injected with [123I]MIBG and acquired 2 h later using an ultrafast CZT gamma camera to assess the regional myocardial uptake. After image acquisition, animals were euthanized; the heart was quickly excised and underwent to an ex vivo single photon emission tomography (SPECT) imaging. Four small samples of tissue were then harvested from mid-walls and apex of the left ventricle; NET densities were evaluated and further normalized for protein loading per cardiac region. RESULTS: Three variants of NET protein with different molecular weights were detected. The expression of NET was not homogenous in the LV, with the highest density in the inferior wall and the lowest one in the apical area. The regional in vivo [123I]MIBG uptake revealed an analogous trend, showing a good linear relationship with NET expression. Parallel results were obtained from the ex vivo study. CONCLUSION: This study elucidates the expression of three different variants of NET proteins into the left ventricular myocardium of a healthy pig. NET expression into the LV was not homogeneous and paralleled by differences in regional [123I]MIBG uptake. Moreover, the correlation and the agreement between measurements of regional expression of NET variants and [123I]MIBG uptake represent a relevant finding for inferences about NET expression in the context of clinical imaging.
Subject(s)
3-Iodobenzylguanidine/metabolism , Iodine Radioisotopes/chemistry , Myocardium/metabolism , Norepinephrine Plasma Membrane Transport Proteins/metabolism , Animals , Heart Ventricles/metabolism , Perfusion , Swine , Tomography, Emission-Computed, Single-PhotonABSTRACT
The data presented in this article are related to the research article entitled: "Accuracy of cadmium-zinc-telluride imaging in detecting single and multivessel coronary artery disease: is there any gender difference?" (Gimelli et al., 2018). We evaluated gender-related differences in diagnostic accuracy of cadmium-zinc-telluride (CZT) myocardial perfusion imaging (MPI) in detecting single- and multi-vessel coronary artery disease (CAD). We included 1161 consecutive patients with known or suspected coronary artery disease (228, 25% women and 873, 75% men) who had been referred to our laboratory for stress-rest myocardial perfusion imaging (single-day stress-rest low-dose ultrafast protocol). All patients underwent coronary angiography within 30 days; CAD was defined in the presence of a coronary stenosis >70%. Summed stress scores (SSS), summed rest scores (SRS) and summed difference scores (SDS) were obtained. Image quality was graded "good" or better in more than 90% of patients.
ABSTRACT
UNLABELLED: The aim of this study was to compare (99m)Tc-tetrofosmin SPECT with contrast-enhanced MRI (ceMRI), a new direct sign of myocardial fibrosis. METHODS: We studied 21 patients (age, 60 +/- 11 y; 19 male) with previous myocardial infarction and severe left ventricular dysfunction (ceMRI EF, 29% +/- 6%). All patients underwent resting and postnitrate (intravenous isosorbide dinitrate) (99m)Tc-tetrofosmin gated SPECT as well as ceMRI. Scintigraphic analysis was performed using quantitative perfusion SPECT (QPS), providing the percentage radiotracer uptake and defect severity in a 20-segment model. Hyperenhancement was defined by the increase of ceMRI signal intensity 20 min after intravenous injection of gadolinium-diethylenetriaminepentaacetic acid and its regional extension as the percentage of the total segment area. RESULTS: In ceMRI dysfunctional segments, the correlation between the extent of hyperenhancement and both (99m)Tc-tetrofosmin uptake and defect severity was significantly better after nitrate administration rather than at rest (P < 0.0001). Using a ceMRI cutoff below 40%, 102 of 196 (52%) segments were viable, whereas 94 (48%) segments were not viable. According to receiver-operating characteristic curve analysis, diagnostic accuracies were higher for postnitrate (99m)Tc-tetrofosmin uptake as well as perfusion defect severity than using resting data (0.84 vs. 0.71, P < 0.001; 0.89 vs. 0.76, P < 0.001, respectively). CONCLUSION: After nitrate administration, (99m)Tc-tetrofosmin uptake and perfusion defect severity were closely related to ceMRI, demonstrating, in vivo, the existence of an inverse correlation between the transmural distribution of fibrosis and tracer delivery to the myocardium.
Subject(s)
Magnetic Resonance Imaging/methods , Myocardial Infarction/diagnostic imaging , Nitrates , Organophosphorus Compounds , Organotechnetium Compounds , Tomography, Emission-Computed, Single-Photon/methods , Ventricular Dysfunction, Left/diagnostic imaging , Adult , Aged , Aged, 80 and over , Contrast Media , Exercise Test , Female , Gadolinium DTPA , Heart/diagnostic imaging , Humans , Male , Middle Aged , Myocardial Infarction/complications , Myocardium/pathology , Radiopharmaceuticals , Reproducibility of Results , Sensitivity and Specificity , Severity of Illness Index , Ventricular Dysfunction, Left/etiologyABSTRACT
BACKGROUND: A novel technology has been developed for ultrafast (UF) single-photon emission CT (SPECT) myocardial perfusion imaging by using a pinhole collimation design and multiple cadmium zinc telluride crystal arrays. The purpose of this study was to compare myocardial perfusion imaging obtained by UF-SPECT with standard (S) SPECT in patients with known or suspected coronary artery disease. METHODS AND RESULTS: A total of 34 patients underwent single-day (99m)Tc-tetrofosmin stress/rest myocardial perfusion imaging. UF-SPECT was performed 10 minutes before S-SPECT. Images were qualitatively analyzed, and the summed stress score and summed rest score were calculated. The segmental tracer uptake value (percentage of maximum myocardial uptake) also was quantified for both UF- and S-SPECT. When only 29 of 34 patients with significant coronary lesions were analyzed, the summed stress score was 10.1±4.4 versus 6.4±2.9, respectively, for UF- and S-SPECT (P=0.002). Qualitative and quantitative per-patient analysis showed similar results in detection of coronary artery disease for UF- and S-SPECT. In contrast, per-vessel analysis demonstrated higher regional sensitivity of UF- versus S-SPECT. UF-SPECT showed higher sensitivity in detecting multivessel disease (P=0.003) versus S-SPECT. CONCLUSIONS: This pilot study confirms that UF-SPECT provides high-quality fast myocardial perfusion imaging and suggests that it may allow a more-accurate evaluation of both extent and severity of myocardial ischemia in patients with coronary artery disease.
Subject(s)
Coronary Artery Disease/diagnostic imaging , Tomography, Emission-Computed, Single-Photon/methods , Coronary Vessels/diagnostic imaging , Female , Humans , Male , Middle Aged , Organotechnetium Compounds , Pilot Projects , Prospective Studies , Radiopharmaceuticals , Technetium , Time FactorsABSTRACT
PURPOSE: This study aims to investigate the relationship between cardiac sympathetic nervous function (CSNF) and myocardial perfusion/function in patients with heart failure (HF) due to dilated cardiomyopathy (DCM) or ischaemic heart disease (CAD). METHODS: Twenty patients (10 DCM, 10 CAD, 17 males, age 69+/-5 years) with NYHA class IIIb HF were studied. CSNF was evaluated by early/delayed (123)I-metaiodobenzylguanidine (MIBG) uptake and regional washout (WO). Myocardial perfusion and function were evaluated by (99m)Tc-tetrofosmin gated single-photon emission tomography (G-SPECT) using a 20-segment model for 400 segments. In each segment, regional MIBG WO was computed as (count density in early images-count density in delayed images/count density in early images)x100. RESULTS: DCM and CAD showed similar summed rest perfusion score (6.7+/-5 vs 9.5+/-5, p=NS) and mean ejection fraction values (29+/-7% vs 30+/-9%, p=NS). By contrast, the summed thickening score was higher in DCM than in CAD patients (26+/-7 vs 17+/-6, p<0.05). QGS analysis identified akinesis/dyskinesis in 129/137 (94%) severely hypoperfused segments which were considered as damaged. According to the underlying aetiology of HF, marked differences in regional MIBG WO were observed. In fact, within the CAD group, regional MIBG WO was lower in reference than in damaged segments (38+/-21% vs 46+/-19%, p<0.05). By contrast, in DCM patients, regional MIBG WO was faster in reference than in damaged segments (49+/-18% vs 41+/-30%, p<0.05). When the two groups were directly compared, regional MIBG WO from damaged areas was similar irrespective of the underlying disease, while it was faster in DCM than in CAD patients from reference segments. CONCLUSION: These data confirm the hypothesis that the presence of myocardial necrosis in HF due to CAD and the consequent loss of neuronal endings cause alterations in regional MIBG WO different from those observed in DCM.
Subject(s)
3-Iodobenzylguanidine/pharmacokinetics , Autonomic Nervous System Diseases/metabolism , Cardiomyopathy, Dilated/metabolism , Coronary Artery Disease/metabolism , Heart Failure/metabolism , Myocardial Ischemia/metabolism , Aged , Autonomic Nervous System Diseases/complications , Autonomic Nervous System Diseases/diagnostic imaging , Cardiomyopathy, Dilated/complications , Cardiomyopathy, Dilated/diagnostic imaging , Coronary Artery Disease/complications , Coronary Artery Disease/diagnostic imaging , Heart/diagnostic imaging , Heart/innervation , Heart Failure/diagnostic imaging , Heart Failure/etiology , Humans , Male , Myocardial Ischemia/complications , Myocardial Ischemia/diagnostic imaging , Myocardium/pathology , Radionuclide Imaging , Radiopharmaceuticals/pharmacokinetics , Reproducibility of Results , Sensitivity and Specificity , Severity of Illness IndexABSTRACT
BACKGROUND: Positron emission tomography (PET) flow/metabolic mismatch is considered the nuclear medicine gold standard for the assessment of myocardial viability. The aim of this study was to investigate whether baseline/nitrate technetium 99m tetrofosmin single photon emission computed tomography (SPECT) mismatch may provide equivalent clinical information. METHODS AND RESULTS: We studied 23 patients (aged 62 +/- 10 years, 19 men) with previous myocardial infarction (16 anterior, 4 inferior, and 3 anterior plus inferior) and postischemic heart failure (gated SPECT [G-SPECT] ejection fraction, 26% +/- 8%). All patients underwent Tc-99m tetrofosmin G-SPECT at rest and after nitrates (intravenous isosorbide dinitrate, 0.2 mg/mL, 10 mL/h) as well as a fluorine 18 fluoro-2-deoxy-d-glucose (FDG) PET scan. Regional wall motion analysis was performed with quantitative G-SPECT (QGS). Myocardial dysfunction was defined as a regional QGS score of 2 or greater. Regional perfusion was assessed by quantitative perfusion score (QPS) providing percent Tc-99m tetrofosmin uptake in a 20-segment model. Semiquantitative analysis of FDG uptake was performed by use of polar maps generated by Siemens ECAT HR + software. In areas with a perfusion rate lower than 80%, PET viability was identified by a normalized FDG percent uptake/baseline Tc-99m tetrofosmin percent uptake ratio greater than 1.2. We analyzed 460 segments; 298 (64%) were dysfunctional by QGS analysis. Of these, 170 were viable by PET imaging whereas 128 were nonviable. Regional Tc-99m tetrofosmin uptake was higher in viable than in nonviable segments both at rest (60% +/- 24% vs 42% +/- 12%, P <.01) and after nitrates (67% +/- 20% vs 41% +/- 18%, P <.01). According to receiver operating characteristic curve analysis, a cutoff value of 63% for resting as well as post-nitrate G-SPECT provided the highest diagnostic accuracy for the detection of myocardial viability (67% and 72% at rest and after nitrates, respectively). When the same algorithm used for the comparison with PET (normalized nitrate percent uptake/baseline percent uptake) was applied to G-SPECT, we obtained the highest agreement with PET (accuracy, 93%; sensitivity, 95%; specificity, 92%). CONCLUSIONS: In patients with severe left ventricular dysfunction, perfusion data alone, both at rest and after nitrates, do not allow an accurate estimate of myocardial viability. In dysfunctioning segments, the analysis of rest/post-nitrate Tc-99m tetrofosmin mismatch provides results similar to those obtained by PET flow/metabolic mismatch.