| 1. |
- Akil, Shahnaz, et al.
(författare)
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Appropriate coronary revascularization can be accomplished if myocardial perfusion is quantified by positron emission tomography prior to treatment decision
- 2021
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Ingår i: Journal of Nuclear Cardiology. - : Springer Science and Business Media LLC. - 1071-3581 .- 1532-6551. ; 28:4, s. 1664-1672
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Tidskriftsartikel (refereegranskat)abstract
- Background: Many patients undergo percutaneous coronary intervention (PCI) without the use of non-invasive stress testing prior to treatment. The aim of this study was to determine the potential added value of guiding revascularization by quantitative assessment of myocardial perfusion prior to intervention. Methods and Results: Thirty-three patients (10 females) with suspected or established CAD who had been referred for a clinical coronary angiography (CA) with possibility for PCI were included. Adenosine stress and rest 13N-NH3 PET, cardiac magnetic resonance (CMR), and cardiopulmonary exercise test were performed 4 ± 3 weeks before and 5 ± 1 months after CA. The angiographer was blinded to the PET and CMR results. Myocardial flow reserve (MFR) < 2.0 by PET was considered abnormal. A PCI was performed in 19/33 patients. In 41% (11/27) of the revascularized vessel territories, a normal regional MFR was found prior to the PCI and no improvement in MFR was found at follow-up (P = 0.9). However, vessel territories with regional MFR < 2.0 at baseline improved significantly after PCI (P = 0.003). Of the 14 patients not undergoing PCI, four had MFR < 2.0 in one or more coronary territories. Conclusion: Assessment of quantitative myocardial perfusion prior to revascularization could lead to more appropriate use of CA when managing patients with stable CAD.
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| 2. |
- Akil, Shahnaz, et al.
(författare)
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Influence of different time framings, reconstruction algorithms and post-processing methods on the quantification of myocardial blood flow from 13N-NH3 PET images
- 2024
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Ingår i: Clinical Physiology and Functional Imaging. - 1475-0961. ; 44:2, s. 154-163
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Tidskriftsartikel (refereegranskat)abstract
- Background: The aim was to investigate to what extent the quantification of myocardial blood flow (MBF) from dynamic 13N-NH3 positron emission tomography (PET) images is affected by time frame schemes, time-of-flight (ToF), reconstruction algorithms, blood pool volume of interest (VOI) locations and compartment models in patients with suspected chronic coronary syndrome. Methods: A standard MBF value was determined from 25 patients' rest/stress 13N-NH3 PET/CT images reconstructed with ordered subset expectation maximization (OSEM), 5 s time frame for the first frames without ToF, subsequently analyzed using a basal VOI and the deGrado compartment model. MBFs calculated using 2 or 10 s for the first frames, ToF, block-sequential regularized expectation maximization (BSREM), apical or large VOI, Hutchins or Krivokapich compartment models were compared to MBFstandard in Bland–Altman plots (bias ± SD). Results: Good agreement in global rest/stress MBF (mL/min/g) was found when changing the time frame scheme or reconstruction algorithm (MBFstandard vs. MBF2s: −0.02 ± 0.06; MBF10s: 0.01 ± 0.07; MBFBSREM: 0.01 ± 0.07), while a lower level of agreement was found when altering the other factors (MBFstandard vs. MBFToF: −0.07 ± 0.10; MBFapical VOI: −0.27 ± 0.25; MBFlarge VOI: −0.11 ± 0.10; MBFHutchins: −0.08 ± 0.10; MBFKrivokapich: −0.47 ± 0.50). Conclusions: Quantification of MBF from 13N-NH3 PET images is more affected by choice of compartment models, ToF and blood pool VOIs than by different time frame schemes and reconstruction algorithms.
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| 3. |
- Akil, Shahnaz, et al.
(författare)
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Qualitative assessments of myocardial ischemia by cardiac MRI and coronary stenosis by invasive coronary angiography in relation to quantitative perfusion by positron emission tomography in patients with known or suspected stable coronary artery disease
- 2020
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Ingår i: Journal of Nuclear Cardiology. - : Springer Science and Business Media LLC. - 1071-3581 .- 1532-6551. ; 27:6, s. 2351-2359
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Tidskriftsartikel (refereegranskat)abstract
- Background: To relate findings of qualitative evaluation of first-pass perfusion-CMR and anatomical evaluation on coronary angiography (CA) to the reference standard of quantitative perfusion, cardiac PET, in patients with suspected or known stable coronary artery disease (CAD). Methods and Results: Forty-one patients referred for CA due to suspected stable CAD, prospectively performed adenosine stress/rest first-pass perfusion-CMR as well as 13N-NH3 PET on the same day, 4 ± 3 weeks before CA. Angiographers were blinded to PET and CMR results. Regional myocardial flow reserve (MFR) < 2.0 on PET was considered pathological. Vessel territories with stress-induced ischemia by CMR or vessels with stenosis needing revascularization had a significantly lower MFR compared to those with no regional stress-induced ischemia or vessels not needing revascularization (P < 0.001). In 4 of 123 vessel territories with stress-induced ischemia by CMR, PET showed a normal MFR. In addition, 12 of 123 vessels that underwent intervention showed normal MFR assessed by PET. Conclusion: The limited performance of qualitative assessment of presence of stable CAD with CMR and CA, when related to quantitative 13N-NH3 cardiac PET, shows the need for fully quantitative assessment of myocardial perfusion and the use of invasive flow reserve measurements for CA, to confirm the need of elective revascularization.
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| 4. |
- Ekenbäck, Christina, et al.
(författare)
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Coronary microvascular dysfunction in Takotsubo syndrome and associations with left ventricular function
- 2023
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Ingår i: ESC Heart Failure. - 2055-5822. ; 10:4, s. 2395-2405
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Tidskriftsartikel (refereegranskat)abstract
- Aims: Coronary microvascular dysfunction (CMD) has been proposed as an important pathophysiological mechanism in Takotsubo syndrome (TTS). Our aims were (i) to evaluate and compare levels of CMD in patients with TTS and patients with ischaemia and no obstructive coronary arteries (INOCA) and (ii) to investigate associations between CMD and clinical parameters, left ventricular function, and coronary atherosclerosis in TTS. Methods and results: We conducted a prospective study of 27 female TTS patients and an equally sized, age- and gender-matched, cohort of INOCA patients. Coronary microvascular function was quantified invasively using the index of microcirculatory resistance (IMR), coronary flow reserve (CFR), and resistive reserve ratio (RRR). CMD was defined as IMR ≥ 25 and/or CFR ≤ 2. In the TTS patients, left ventricular function was assessed with echocardiography and cardiovascular magnetic resonance (CMR) imaging, and coronary atherosclerosis was visualized with intravascular ultrasound with near-infrared spectroscopy (IVUS-NIRS). The incidence of CMD was higher in the TTS patients than in the INOCA cohort (78% vs. 44%, P = 0.01), with higher IMR (30 vs. 14, P = 0.002), lower CFR (1.8 vs. 2.8, P = 0.009), and lower RRR (2.1 vs. 3.5, P = 0.003). In apical compared with midventricular TTS, IMR was numerically higher (50 vs. 28, P = 0.20), whereas CFR and RRR were lower (1.5 vs. 2.5, P = 0.003 and 1.6 vs. 2.7, P = 0.01, respectively). Global longitudinal strain and global circumferential strain, assessed with CMR imaging, were more impaired in apical than in midventricular TTS (−11 vs. −14, P < 0.001 and −12 vs. −15, P = 0.049, respectively). In the TTS patients, CFR and RRR correlated with echocardiography-derived (R2 = 0.15, P = 0.002 and R2 = 0.18, P = 0.007, respectively) and CMR-derived (R2 = 0.09, P = 0.025 and R2 = 0.10, P = 0.038, respectively) ejection fraction. CFR and RRR correlated inversely with CMR-derived end-diastolic volume index, end-systolic volume index, and left ventricular mass index. IMR, CFR, and RRR were not associated with measures of coronary atherosclerosis derived by IVUS-NIRS. Conclusions: Coronary microvascular dysfunction is common in patients with TTS and more frequent than in patients with INOCA. CMD in TTS is more severe in the apical compared with the midventricular phenotype of the syndrome, is associated with left ventricular function, but is unrelated to coronary atherosclerosis. Our results support the notion of CMD as a key mediator in TTS.
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| 5. |
- Engblom, Henrik, et al.
(författare)
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Diagnostic confidence with quantitative cardiovascular magnetic resonance perfusion mapping increases with increased coverage of the left ventricle
- 2024
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Ingår i: Journal of Cardiovascular Magnetic Resonance. - 1097-6647. ; 26:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Quantitative cardiovascular magnetic resonance (CMR) first pass perfusion maps are conventionally acquired with 3 short-axis (SAX) views (basal, mid, and apical) in every heartbeat (3SAX/1RR). Thus, a significant part of the left ventricle (LV) myocardium, including the apex, is not covered. The aims of this study were 1) to investigate if perfusion maps acquired with 3 short-axis views sampled every other RR-interval (2RR) yield comparable quantitative measures of myocardial perfusion (MP) as 1RR and 2) to assess if acquiring 3 additional perfusion views (i.e., total of 6) every other RR-interval (2RR) increases diagnostic confidence. Methods: In 287 patients with suspected ischemic heart disease stress and rest MP were performed on clinical indication on a 1.5T MR scanner. Eighty-three patients were examined by acquiring 3 short-axis perfusion maps with 1RR sampling (3SAX/1RR); for which also 2RR maps were reconstructed. Additionally, in 103 patients 3 short-axis and 3 long-axis (LAX; 2-, 3, and 4-chamber view) perfusion maps were acquired using 2RR sampling (3SAX + 3LAX/2RR) and in 101 patients 6 short-axis perfusion maps using 2RR sampling (6SAX/2RR) were acquired. The diagnostic confidence for ruling in or out stress-induced ischemia was scored according to a Likert scale (certain ischemia [2 points], probably ischemia [1 point], uncertain [0 points], probably no ischemia [1 point], certain no ischemia [2 points]). Results: There was a strong correlation (R = 0.99) between 3SAX/1RR and 3SAX/2RR for global MP (mL/min/g). The diagnostic confidence score increased significantly when the number of perfusion views was increased from 3 to 6 (1.24 ± 0.68 vs 1.54 ± 0.64, p < 0.001 with similar increase for 3SAX+3LAX/2RR (1.29 ± 0.68 vs 1.55 ± 0.65, p < 0.001) and for 6SAX/2RR (1.19 ± 0.69 vs 1.53 ± 0.63, p < 0.001). Conclusion: Quantitative perfusion mapping with 2RR sampling of data yields comparable perfusion values as 1RR sampling, allowing for the acquisition of additional views within the same perfusion scan. The diagnostic confidence for stress-induced ischemia increases when adding 3 additional views, short- or long axes, to the conventional 3 short-axis views. Thus, future development and clinical implementation of quantitative CMR perfusion should aim at increasing the LV coverage from the current standard using 3 short-axis views.
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| 6. |
- Gyllenhammar, Tom, et al.
(författare)
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Myocardial perfusion by CMR coronary sinus flow shows sex differences and lowered perfusion at stress in patients with suspected microvascular angina
- 2022
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Ingår i: Clinical Physiology and Functional Imaging. - : Wiley. - 1475-0961 .- 1475-097X. ; 42:3, s. 208-219
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Tidskriftsartikel (refereegranskat)abstract
- Background: Patients with chest pain may have normal coronary arteries and suffer from microvascular angina (MVA). The aim of this study was to determine if patients with suspected MVA have lower global myocardial perfusion (global MP) during adenosine stress compared with healthy controls and coronary artery disease (CAD) patients and to determine if there are sex differences in global MP. Methods: Twenty-three patients with suspected MVA (66 ± 11 years), 19 CAD patients (69 ± 5 years) with stress-induced ischaemia and 24 healthy controls (61 ± 10 years) underwent cardiac magnetic resonance (CMR) including coronary sinus flow measurements and first-pass perfusion at rest and during adenosine stress. Global MP was quantified as coronary sinus flow normalized to left ventricular mass. Results: Global perfusion was lower during stress in patients with suspected MVA (2.9 ± 1.0 ml/min/g) compared with healthy volunteers (3.7 ± 1.1 ml/min/g, p = 0.018), but higher compared with CAD patients (2.0 ± 0.9 ml/min/g, p = 0.019). Female controls had higher global MP than male controls both at rest (1.0 ± 0.3 vs. 0.7 ± 0.2 ml/min/g, p = 0.003) and during stress (4.4 ± 1.0 vs. 3.1 ± 0.6 ml/min/g, p = 0.001). Furthermore, females with suspected MVA showed higher global MP than males with suspected MVA (3.3 ± 1.0 vs. 2.4 ± 0.7, p = 0.04). Conclusions: Patients with suspected MVA have lower global MP at stress than healthy volunteers but higher than patients with CAD. Furthermore, there seems to be a sex difference in global MP at stress both in healthy volunteers and in patients with suspected MVA, with higher global MP in females, which implies a need for sex-specific normal limits when assessing quantitative MP.
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| 7. |
- Hedeer, Fredrik, et al.
(författare)
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Diagnostic accuracy for CZT gamma camera compared to conventional gamma camera technique with myocardial perfusion single-photon emission computed tomography : Assessment of myocardial infarction and function
- 2023
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Ingår i: Journal of Nuclear Cardiology. - : Springer Science and Business Media LLC. - 1071-3581 .- 1532-6551. ; 30:5, s. 1935-1946
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Tidskriftsartikel (refereegranskat)abstract
- Background: The solid-state cadmium-zinc-telluride (CZT) gamma camera for myocardial perfusion single-photon emission computed tomography (MPS) has theoretical advantages compared to the conventional gamma camera technique. This includes more sensitive detectors and better energy resolution. We aimed to explore the diagnostic performance of gated MPS with a CZT gamma camera compared to a conventional gamma camera for detection of myocardial infarct (MI) and assessment of left ventricular (LV) volumes and ejection fraction (LVEF), using cardiac magnetic resonance (CMR) as the reference method. Methods: Seventy-three patients (26% female) with known or suspected chronic coronary syndrome were examined with gated MPS using both a CZT gamma camera and a conventional gamma camera as well as with CMR. Presence and extent of MI on MPS and late gadolinium enhancement (LGE) CMR was evaluated. For LV volumes, LVEF and LV mass, gated MPS images and cine CMR images were evaluated. Results: MI was found in 42 patients on CMR. The overall sensitivity, specificity, positive and negative predictive values for the CZT and the conventional gamma camera were the same (67%, 100%, 100% and 69%). For infarct size > 3% on CMR, the sensitivity was 82% for the CZT and 73% for the conventional gamma camera, respectively. LV volumes were significantly underestimated by MPS compared to CMR (P ≤.002 for all measures). The underestimation was slightly less pronounced for the CZT compared to the conventional gamma camera (2-10 mL, P ≤.03 for all measures). For LVEF, however, accuracy was high for both gamma cameras. Conclusion: Differences between a CZT and a conventional gamma camera for detection of MI and assessment of LV volumes and LVEF are small and do not appear to be clinically significant.
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| 8. |
- Hedeer, Fredrik, et al.
(författare)
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To what extent are perfusion defects seen by myocardial perfusion SPECT in patients with left bundle branch block related to myocardial infarction, ECG characteristics, and myocardial wall motion?
- 2021
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Ingår i: Journal of Nuclear Cardiology. - : Springer Science and Business Media LLC. - 1071-3581 .- 1532-6551. ; 28:6, s. 2910-2922
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: We investigated if uptake pattern on myocardial perfusion SPECT (MPS) in patients with left bundle branch block (LBBB) is related to myocardial fibrosis, myocardial wall motion, and electrocardiography (ECG) characteristics. Methods: Twenty-three patients (9 women) with LBBB, examined with MPS and cardiac magnetic resonance (CMR), were included. Tracer uptake on MPS was classified by visual interpretation as typical LBBB pattern (Defect+, n = 13) or not (Defect−, n = 10) and quantitatively. CMR images were evaluated for wall thickness and for myocardial wall motion both by visual assessment and by regional myocardial radial strain from feature tracking, and for presence and location of myocardial fibrosis. ECGs were analyzed regarding QRS duration and the presence of strict criteria for LBBB. Results: Wall thickness was slightly lower in the septum compared to the lateral wall in Defect+ patients (5.6 ± 1.1 vs 6.0 ± 1.3 mm, P = 0.03) but not in Defect− patients (5.6 ± 1.0 vs 5.6 ± 0.9 mm, P = 0.84). Defect+ patients showed a larger proportion of dyskinetic segments in the septum and hyperkinetic segments in the lateral wall compared to Defect− patients (P = 0.006 and P = 0.004, respectively). Decreased myocardial radial strain was associated with decreased tracer uptake by MPS (R = 0.37, P < 0.001). Areas of fibrosis did not match areas with uptake defect on MPS. No differences in ECG variables were seen. Conclusion: The heterogeneous regional tracer uptake in some patients with LBBB is related to underlying regional myocardial dyskinesia, wall thickening, and wall thickness rather than stress-induced ischemia, myocardial fibrosis, or specific ECG characteristics.
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| 9. |
- Heiberg, Einar, et al.
(författare)
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Infarct quantification with cardiovascular magnetic resonance using "standard deviation from remote" is unreliable : validation in multi-centre multi-vendor data
- 2022
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Ingår i: Journal of Cardiovascular Magnetic Resonance. - : Springer Science and Business Media LLC. - 1097-6647 .- 1532-429X. ; 24:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: The objective of the study was to investigate variability and agreement of the commonly used image processing method “n-SD from remote” and in particular for quantifying myocardial infarction by late gadolinium enhancement (LGE) cardiovascular magnetic resonance (CMR). LGE-CMR in tandem with the analysis method “n-SD from remote” represents the current reference standard for infarct quantification. This analytic method utilizes regions of interest (ROIs) and defines infarct as the tissue with a set number of standard deviations (SD) above the signal intensity of remote nulled myocardium. There is no consensus on what the set number of SD is supposed to be. Little is known about how size and location of ROIs and underlying signal properties in the LGE images affect results. Furthermore, the method is frequently used elsewhere in medical imaging often without careful validation. Therefore, the usage of the “n-SD” method warrants a thorough validation. Methods: Data from 214 patients from two multi-center cardioprotection trials were included. Infarct size from different remote ROI positions, ROI size, and number of standard deviations (“n-SD”) were compared with reference core lab delineations. Results: Variability in infarct size caused by varying ROI position, ROI size, and “n-SD” was 47%, 48%, and 40%, respectively. The agreement between the “n-SD from remote” method and the reference infarct size by core lab delineations was low. Optimal “n-SD” threshold computed on a slice-by-slice basis showed high variability, n = 5.3 ± 2.2. Conclusion: The “n-SD from remote” method is unreliable for infarct quantification due to high variability which depends on different placement and size of remote ROI, number “n-SD”, and image signal properties related to the CMR-scanner and sequence used. Therefore, the “n-SD from remote” method should not be used, instead methods validated against an independent standard are recommended.
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| 10. |
- Jablonowski, Robert, et al.
(författare)
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Quantitative myocardial perfusion during stress using CMR is impaired in healthy Middle Eastern immigrants without CV risk factors
- 2022
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- Middle Eastern immigrants constitute a growing proportion of the European population and compared to native Swedes are more insulin resistant, which can contribute to atherosclerosis. Quantitative first pass perfusion (qFPP) using cardiovascular magnetic resonance (CMR) can detect early signs of cardiovascular disease (CVD). The aim was to study if myocardial perfusion differs between healthy male Middle Eastern immigrants and native male Swedes. Eighteen Iraqi- and twelve Swedish born controls, all males, never smokers with no CVD risk factors were included. Global myocardial perfusion at rest and stress was assessed using qFPP and by phase-contrast CMR imaging of coronary sinus flow. Quantitative first pass perfusion analysis (mean ± SD) demonstrated no difference at rest between Iraqi and Swedish males (0.8 ± 0.2 vs 1.0 ± 0.4 ml/min/g, P = 0.38) but lower perfusion during adenosine in Iraqi males (2.9 ± 0.7 vs 3.5 ± 0.7 ml/min/g, P = 0.02). Myocardial perfusion assessed by coronary sinus flow demonstrated similar results with no difference in resting perfusion between groups (0.7 ± 0.2 vs 0.8 ± 0.2 ml/min/g, P = 0.21) but a lower perfusion during adenosine in the Iraqi group (3.0 ± 0.2 vs 3.7 ± 0.6 ml/min/g, P = 0.01. Myocardial perfusion during adenosine stress was lower in healthy Iraqi immigrants compared to Swedish controls suggesting impaired microvascular function and risk of underestimating CVD risk in healthy individuals of Middle Eastern origin.
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