First-pass Perfusion Research Articles

306 - First-pass perfusion imaging to improve the assessment of left ventricular thrombus following a myocardial infarction

Abstract Purpose To assess whether a first-pass perfusion sequence (FPP) improved the detection of left ventricular thrombus (LVT). Materials and methods Three hundred and twenty-nine patients with a first STEMI were prospectively included to undergo cardiac magnetic resonance (CMR) at baseline and after a 3-month follow-up. A CMR delayed analysis was performed by three blinded examiners (2 CMR experts and 1 novice) according to a two-step reading protocol. First, an analysis was performed on cine CMR and late gadolinium enhancement (routine stage). Then, the FPP stage was performed following initial protocol along with a FPP sequence. Results LVT was found in 31 out of a total of 638 (4.9%) CMR scans, affecting 30 (9.1%) individuals. All were located in the left ventricular apex. The FPP stage improved significantly the LVT diagnosis for all readers, in 10 and 13 cases (32% and 42%) of LVT suspicion for the experts and 16 cases (41%) for the novice. Respectively 1, 2 and 6 LVT were not detected during the routine stage by the CMR experts and the novice. For the novice, the FPP stage improved diagnosis sensitivity from 78.1 to 91.2%. Conclusions The prevalence of LVT following a myocardial infarction reached 9.1% and increased with the reading of FPP sequence. The FPP stage improved expert diagnostic certitude and the novice’s abilities to reach expert level.

033 - Subepicardial hyperemia on contrast-enhanced first-pass magnetic resonance perfusion imaging is useful for the diagnosis of acute myocarditis

033 - Subepicardial hyperemia on contrast-enhanced first-pass magnetic resonance perfusion imaging is useful for the diagnosis of acute myocarditis

Hyperpolarized 13C urea myocardial first-pass perfusion imaging using velocity-selective excitation

BackgroundA velocity-selective binomial excitation scheme for myocardial first-pass perfusion measurements with hyperpolarized 13C substrates, which preserves bolus magnetization inside the blood pool, is presented. The proposed method is evaluated against gadolinium-enhanced 1H measurements in-vivo.MethodsThe proposed excitation with an echo-planar imaging readout was implemented on a clinical CMR system. Dynamic myocardial stress perfusion images were acquired in six healthy pigs after bolus injection of hyperpolarized 13C urea with the velocity-selective vs. conventional excitation, as well as standard 1H gadolinium-enhanced images. Signal-to-noise, contrast-to-noise (CNR) and homogeneity of semi-quantitative perfusion measures were compared between methods based on first-pass signal-intensity time curves extracted from a mid-ventricular slice. Diagnostic feasibility is demonstrated in a case of septal infarction.ResultsVelocity-selective excitation provides over three-fold reduction in blood pool signal with a two-fold increase in myocardial CNR. Extracted first-pass perfusion curves reveal a significantly reduced variability of semi-quantitative first-pass perfusion measures (12–20%) for velocity-selective excitation compared to conventional excitation (28–93%), comparable to that of reference 1H gadolinium data (9–15%). Overall image quality appears comparable between the velocity-selective hyperpolarized and gadolinium-enhanced imaging.ConclusionThe feasibility of hyperpolarized 13C first-pass perfusion CMR has been demonstrated in swine. Comparison with reference 1H gadolinium data revealed sufficient data quality and indicates the potential of hyperpolarized perfusion imaging for human applications.

Analysis of spatiotemporal fidelity in quantitative 3D first-pass perfusion cardiovascular magnetic resonance

BackgroundWhole-heart first-pass perfusion cardiovascular magnetic resonance (CMR) relies on highly accelerated image acquisition. The influence of undersampling on myocardial blood flow (MBF) quantification has not been systematically investigated yet. In the present work, the effect of spatiotemporal scan acceleration on image reconstruction accuracy and MBF error was studied using a numerical phantom and validated in-vivo.MethodsUp to 10-fold scan acceleration using k-t PCA and k-t SPARSE-SENSE was simulated using the MRXCAT CMR numerical phantom framework. Image reconstruction results were compared to ground truth data in the k-f domain by means of modulation transfer function (MTF) analysis. In the x-t domain, errors pertaining to specific features of signal intensity-time curves and MBF values derived using Fermi model deconvolution were analysed. In-vivo first-pass CMR data were acquired in ten healthy volunteers using a dual-sequence approach assessing the arterial input function (AIF) and myocardial enhancement. 10x accelerated 3D k-t PCA and k-t SPARSE-SENSE were compared and related to non-accelerated 2D reference images.ResultsMTF analysis revealed good recovery of data upon k-t PCA reconstruction at 10x undersampling with some attenuation of higher temporal frequencies. For 10x k-t SPARSE-SENSE the MTF was found to decrease to zero at high spatial frequencies for all temporal frequencies indicating a loss in spatial resolution. Signal intensity-time curve errors were most prominent in AIFs from 10x k-t PCA, thereby emphasizing the need for separate AIF acquisition using a dual-sequence approach. These findings were confirmed by MBF estimation based on AIFs from fully sampled and undersampled simulations. Average in-vivo MBF estimates were in good agreement between both accelerated and the fully sampled methods. Intra-volunteer MBF variation for fully sampled 2D scans was lower compared to 10x k-t PCA and k-t SPARSE-SENSE data.ConclusionQuantification of highly undersampled 3D first-pass perfusion CMR yields accurate MBF estimates provided the AIF is obtained using fully sampled or moderately undersampled scans as part of a dual-sequence approach. However, relative to fully sampled 2D perfusion imaging, intra-volunteer variation is increased using 3D approaches prompting for further developments.

Adenosine stress CMR T1-mapping detects early microvascular dysfunction in patients with type 2 diabetes mellitus without obstructive coronary artery disease

BackgroundType 2 diabetes mellitus (T2DM) is associated with coronary microvascular dysfunction in the absence of obstructive coronary artery disease (CAD). Cardiovascular magnetic resonance (CMR) T1-mapping at rest and during adenosine stress can assess coronary vascular reactivity. We hypothesised that the non-contrast T1 response to vasodilator stress will be altered in patients with T2DM without CAD compared to controls due to coronary microvascular dysfunction.MethodsThirty-one patients with T2DM and sixteen matched healthy controls underwent CMR (3 T) for cine, rest and adenosine stress non-contrast T1-mapping (ShMOLLI), first-pass perfusion and late gadolinium enhancement (LGE) imaging. Significant CAD (>50% coronary luminal stenosis) was excluded in all patients by coronary computed tomographic angiography.ResultsAll subjects had normal left ventricular (LV) ejection and LV mass index, with no LGE. Myocardial perfusion reserve index (MPRI) was lower in T2DM than in controls (1.60 ± 0.44 vs 2.01 ± 0.42; p = 0.008). There was no difference in rest native T1 values (p = 0.59). During adenosine stress, T1 values increased significantly in both T2DM patients (from 1196 ± 32 ms to 1244 ± 44 ms, p < 0.001) and controls (from 1194 ± 26 ms to 1273 ± 44 ms, p < 0.001). T2DM patients showed blunted relative stress non-contrast T1 response (T2DM: ΔT1 = 4.1 ± 2.9% vs. controls: ΔT1 = 6.6 ± 2.6%, p = 0.007) due to a blunted maximal T1 during adenosine stress (T2DM 1244 ± 44 ms vs. controls 1273 ± 44 ms, p = 0.045).ConclusionsPatients with well controlled T2DM, even in the absence of arterial hypertension and significant CAD, exhibit blunted maximal non-contrast T1 response during adenosine vasodilatory stress, likely reflecting coronary microvascular dysfunction. Adenosine stress and rest T1 mapping can detect subclinical abnormalities of the coronary microvasculature, without the need for gadolinium contrast agents. CMR may identify early features of the diabetic heart phenotype and subclinical cardiac risk markers in patients with T2DM, providing an opportunity for early therapeutic intervention.

Splenic T1-mapping: a novel quantitative method for assessing adenosine stress adequacy for cardiovascular magnetic resonance

BackgroundPerfusion cardiovascular magnetic resonance (CMR) performed with inadequate adenosine stress leads to false-negative results and suboptimal clinical management. The recently proposed marker of adequate stress, the “splenic switch-off” sign, detects splenic blood flow attenuation during stress perfusion (spleen appears dark), but can only be assessed after gadolinium first-pass, when it is too late to optimize the stress response. Reduction in splenic blood volume during adenosine stress is expected to shorten native splenic T1, which may predict splenic switch-off without the need for gadolinium.MethodsTwo-hundred and twelve subjects underwent adenosine stress CMR: 1.5 T (n = 104; 75 patients, 29 healthy controls); 3 T (n = 108; 86 patients, 22 healthy controls). Native T1spleen was assessed using heart-rate-independent ShMOLLI prototype sequence at rest and during adenosine stress (140 μg/kg/min, 4 min, IV) in 3 short-axis slices (basal, mid-ventricular, apical). This was compared with changes in peak splenic perfusion signal intensity (ΔSIspleen) and the “splenic switch-off” sign on conventional stress/rest gadolinium perfusion imaging. T1spleen values were obtained blinded to perfusion ΔSIspleen, both were derived using regions of interest carefully placed to avoid artefacts and partial-volume effects.ResultsNormal resting splenic T1 values were 1102 ± 66 ms (1.5 T) and 1352 ± 114 ms (3 T), slightly higher than in patients (1083 ± 59 ms, p = 0.04; 1295 ± 105 ms, p = 0.01, respectively). T1spleen decreased significantly during adenosine stress (mean ΔT1spleen ~ −40 ms), independent of field strength, age, gender, and cardiovascular diseases. While ΔT1spleen correlated strongly with ΔSIspleen (rho = 0.70, p < 0.0001); neither indices showed significant correlations with conventional hemodynamic markers (rate pressure product) during stress. By ROC analysis, a ΔT1spleen threshold of ≥ −30 ms during stress predicted the “splenic switch-off” sign (AUC 0.90, p < 0.0001) with sensitivity (90%), specificity (88%), accuracy (90%), PPV (98%), NPV (42%).ConclusionsAdenosine stress and rest splenic T1-mapping is a novel method for assessing stress responses, independent of conventional hemodynamic parameters. It enables prediction of the visual “splenic switch-off” sign without the need for gadolinium, and correlates well to changes in splenic signal intensity during stress/rest perfusion imaging. ΔT1spleen holds promise to facilitate optimization of stress responses before gadolinium first-pass perfusion CMR.

Myocardial perfusion in peripheral Raynaud's phenomenon. Evaluation using stress cardiovascular magnetic resonance

BackgroundPeripheral Raynaud's phenomenon (RP) is either primary (PRP), without any coexisting disease or secondary (SRP), due to connective tissue diseases (CTD). We hypothesized that adenosine stress cardiovascular magnetic resonance (CMR) can assess myocardial perfusion in a population of PRP and SRP. Patients-methodsTwenty CTDs, aged 30.6±7.5yrs., 16F/4M, including 9 systemic sclerosis (SSc), 4 systemic lupus erythematosus (SLE), 3 mixed connective tissue disease (MCTD), 2 polymyositis (PM) and 2 rheumatoid arthritis (RA), with SRP, under treatment with calcium blockers, were evaluated by stress CMR and compared with age-sex matched PRP and controls. All RP patients were under treatment with calcium blockers. Stress perfusion CMR was performed by 1.5T system using 140mg/kg/min adenosine for 4min and 0.05mmol/kg Gd-DTPA for first-pass perfusion. A rest perfusion was performed with the same protocol. Late gadolinium enhanced (LGE) images were acquired after another dose of Gd-DTPA. ResultsIn both PRP, SRP, the myocardial perfusion reserve index (MPRI) was significantly reduced compared with the controls (1.7±0.6 vs 3.5±0.4, p<0.001 and 0.7±0.2 vs 3.5±0.4, p<0.001, respectively). Furthermore, in SRP, MPRI was significantly reduced, compared with PRP (0.7±0.2 vs 1.7±0.6, p<0.001). Subendo-cardial LGE=8.2±1.7 of LV mass was revealed in 1 SLE, 1MCTD and 2 SSc, but in none of PR patients. ConclusionsMPRI reduction is common in both PRP and SRP, but it is more severe in SRP, even if RP patients are under treatment with calcium blockers. Occult fibrosis may coexist with the reduced MPRI in SRP but not in PRP.

Mechanisms of Myocardial Ischemia in Hypertrophic Cardiomyopathy: Insights From Wave Intensity Analysis and Magnetic Resonance

BackgroundAngina is common in hypertrophic cardiomyopathy (HCM) and is associated with abnormal myocardial perfusion. Wave intensity analysis improves the understanding of the mechanics of myocardial ischemia. ObjectivesWave intensity analysis was used to describe the mechanisms underlying perfusion abnormalities in patients with HCM. MethodsSimultaneous pressure and flow were measured in the proximal left anterior descending artery in 33 patients with HCM and 20 control patients at rest and during hyperemia, allowing calculation of wave intensity. Patients also underwent quantitative first-pass perfusion cardiac magnetic resonance to measure myocardial perfusion reserve. ResultsPatients with HCM had a lower coronary flow reserve than control subjects (1.9 ± 0.8 vs. 2.7 ± 0.9; p = 0.01). Coronary hemodynamics in HCM were characterized by a very large backward compression wave during systole (38 ± 11% vs. 21 ± 6%; p < 0.001) and a proportionately smaller backward expansion wave (27% ± 8% vs. 33 ± 6%; p = 0.006) compared with control subjects. Patients with severe left ventricular outflow tract obstruction had a bisferiens pressure waveform resulting in an additional proximally originating deceleration wave during systole. The proportion of waves acting to accelerate coronary flow increased with hyperemia, and the magnitude of change was proportional to the myocardial perfusion reserve (rho = 0.53; p < 0.01). ConclusionsCoronary flow in patients with HCM is deranged. Distally, compressive deformation of intramyocardial blood vessels during systole results in an abnormally large backward compression wave, whereas proximally, severe left ventricular outflow tract obstruction is associated with an additional deceleration wave. Perfusion abnormalities in HCM are not simply a consequence of supply/demand mismatch or remodeling of the intramyocardial blood vessels; they represent a dynamic interaction with the mechanics of myocardial ischemia that may be amenable to treatment.

Quantitative Perfusion Analysis of First-Pass Contrast Enhancement Kinetics: Application to MRI of Myocardial Perfusion in Coronary Artery Disease.

PurposePerfusion analysis from first-pass contrast enhancement kinetics requires modeling tissue contrast exchange. This study presents a new approach for numerical implementation of the tissue homogeneity model, incorporating flexible distance steps along the capillary (NTHf).MethodsThe proposed NTHf model considers contrast exchange in fluid packets flowing along the capillary, incorporating flexible distance steps, thus allowing more efficient and stable calculations of the transit of tracer through the tissue. We prospectively studied 8 patients (62 ± 13 years old) with suspected CAD, who underwent first-pass perfusion CMR imaging at rest and stress prior to angiography. Myocardial blood flow (MBF) and myocardial perfusion reserve index (MPRI) were estimated using both the NTHf and the conventional adiabatic approximation of the TH models. Coronary artery lesions detected at angiography were clinically assigned to one of three categories of stenosis severity (‘insignificant’, ‘mild to moderate’ and ‘severe’) and related to corresponding myocardial territories.ResultsThe mean MBF (ml/g/min) at rest/stress and MPRI were 0.80 ± 0.33/1.25 ± 0.45 and 1.68 ± 0.54 in the insignificant regions, 0.74 ± 0.21/1.09 ± 0.28 and 1.54 ± 0.46 in the mild to moderate regions, and 0.79 ± 0.28/0.63 ± 0.34 and 0.85 ± 0.48 in the severe regions, respectively. The correlation coefficients of MBFs at rest/stress and MPRI between the NTHf and AATH models were r = 0.97/0.93 and r = 0.91, respectively.ConclusionsThe proposed NTHf model allows efficient quantitative analysis of the transit of tracer through tissue, particularly at higher flow. Results of initial application to MRI of myocardial perfusion in CAD are encouraging.

First-pass myocardial perfusion MRI with reduced subendocardial dark-rim artifact using optimized Cartesian sampling.

The presence of subendocardial dark-rim artifact (DRA) remains an ongoing challenge in first-pass perfusion (FPP) cardiac magnetic resonance imaging (MRI). We propose a free-breathing FPP imaging scheme with Cartesian sampling that is optimized to minimize the DRA and readily enables near-instantaneous image reconstruction. The proposed FPP method suppresses Gibbs ringing effects-a major underlying factor for the DRA-by "shaping" the underlying point spread function through a two-step process: 1) an undersampled Cartesian sampling scheme that widens the k-space coverage compared to the conventional scheme; and 2) a modified parallel-imaging scheme that incorporates optimized apodization (k-space data filtering) to suppress Gibbs-ringing effects. Healthy volunteer studies (n = 10) were performed to compare the proposed method against the conventional Cartesian technique-both using a saturation-recovery gradient-echo sequence at 3T. Furthermore, FPP imaging studies using the proposed method were performed in infarcted canines (n = 3), and in two symptomatic patients with suspected coronary microvascular dysfunction for assessment of myocardial hypoperfusion. Width of the DRA and the number of DRA-affected myocardial segments were significantly reduced in the proposed method compared to the conventional approach (width: 1.3 vs. 2.9 mm, P < 0.001; number of segments: 2.6 vs. 8.7; P < 0.0001). The number of slices with severe DRA was markedly lower for the proposed method (by 10-fold). The reader-assigned image quality scores were similar (P = 0.2), although the quantified myocardial signal-to-noise ratio was lower for the proposed method (P < 0.05). Animal studies showed that the proposed method can detect subendocardial perfusion defects and patient results were consistent with the gold-standard invasive test. The proposed free-breathing Cartesian FPP imaging method significantly reduces the prevalence of severe DRAs compared to the conventional approach while maintaining similar resolution and image quality. 2 J. Magn. Reson. Imaging 2017;45:542-555.

First pass perfusion imaging to improve the assessment of left ventricular thrombus following a myocardial infarction

PurposeTo assess whether a first-pass perfusion sequence (FPP) improved the detection of left ventricular thrombus (LVT). Materials and methodsThree hundred and twenty-nine patients with a first STEMI were prospectively included to undergo cardiac magnetic resonance (CMR) at baseline and after a 3-month follow-up. A CMR delayed analysis was performed by three blinded examiners (2 CMR experts and 1 novice) according to a two-step reading protocol. First, an analysis was performed on cine CMR and late gadolinium enhancement (routine stage). Then, the FPP stage was performed following initial protocol along with a FPP sequence. ResultsLVT was found in 31 out of a total of 638 (4.9%) CMR scans, affecting 30 (9.1%) individuals. All were located in the left ventricular apex. The FPP stage improved significantly the LVT diagnosis for all readers, in 10 and 13 cases (32% and 42%) of LVT suspicion for the experts and 16 cases (41%) for the novice. Respectively 1, 2 and 6 LVT were not detected during the routine stage by the CMR experts and the novice. For the novice, the FPP stage improved diagnosis sensitivity from 78.1 to 91.2%. ConclusionsThe prevalence of LVT following a myocardial infarction reached 9.1% and increased with the reading of FPP sequence. The FPP stage improved expert diagnostic certitude and the novice’s abilities to reach expert level.

Usefulness of Subepicardial Hyperemia on Contrast-Enhanced First-Pass Magnetic Resonance Perfusion Imaging for Diagnosis of Acute Myocarditis

Hyperemia is a major criterion for the diagnosis of acute myocarditis on cardiac magnetic resonance imaging but its assessment is challenging and time consuming. We evaluated the usefulness of the contrast-enhanced first-pass perfusion (FPP) on magnetic resonance imaging for detecting subepicardial hyperemia in acute myocarditis. Forty-seven consecutive patients (mean age: 42 ± 15.6years; 35 men) with a definite diagnosis of acute myocarditis according to the state-of-the-art guidelines were included and compared with 16 control subjects. FPP was evaluated by 2 blinded observers and compared with the reference late gadolinium enhancement. Detection of hyperemia was performed on both qualitative and quantitative methods. Relative increased signal intensity (SI) in the subepicardial hyperemic layer was measured with SI ratio (SI of the subepicardial layer/SI of the immediately adjacent subendocardial layer). Twenty-four patients (51%) with acute myocarditis exhibited subepicardial hyperemia, detected with a good interobserver reproducibility (kappa coefficient: 0.75). The SI in the myocardium of myocarditis patients was increased compared with controls (1.08 ± 0.03 vs 0.945 ± 0.04, p= 0.03) and the SI in myocarditis patients with hyperemia compared with those without hyperemia (1.22 ± 0.04 vs 0.94 ± 0.04, p <0.0001). Sensitivity, specificity, positive predictive, and negative predictive values of FPP for detecting hyperemia were 85%, 94%, 85%, and 93%, respectively. In conclusion, contrast-enhanced first-pass magnetic resonance imaging is a fast and useful method for assessing myocardial hyperemia in patients with acute myocarditis.

4 A comprehensive assessment of the effect of recanalisation of chronic total occlusion

Background Successful recanalisation of chronic total occlusion (CTO) is associated with improved mortality but a strong correlation with burden of ischaemia and symptoms is lacking. Myocardial perfusion reserve (MPR) by first-pass perfusion cardiac magnetic resonance imaging (CMR) is an accurate non-invasive measure of myocardial ischaemia. We evaluated the effect of percutaneous coronary intervention (PCI) on MPR, left ventricular ejection fraction (LVEF), angina, quality of life and six-minute walking distance (6MWD). Methods and Results To date, 40 patients have undergone contrast-enhanced first-pass perfusion CMR, modified angina questionnaire, quality of life Short-Form 36 (SF-36) assessment and six-minute walk test before and 6 months after successful PCI. MPR was analysed by measuring the relative upslope of the signal intensity curves at stress and rest calculated for a 16 segment AHA model. MPR increased by 0.59 (95% CI, 0.32 to 0.87), p Conclusions Successful recanalisation of CTO by PCI leads to a reduction in ischaemia measured by MPR, as well as an improvement in LVEF (particularly in impaired ventricles), frequency of angina, overall quality of life and 6MWD at 6 months.

16 The cardiac toxicity CMR study in patients with lung cancer treated with chemo-radiotherapy: The cart study- a semi quantitative analysis of the myocardial perfusion index

Background There are limited data on the cardiac effects of radiotherapy and chemo-radiotherapy on the heart in patients with non-small cell lung cancer (NSCLC). CART is a pilot study designed to investigate change in myocardial function and tissue properties where Patients will undergo cardiac magnetic resonance (CMR) at baseline, during treatment, at 6 weeks and at 6 months after treatment completion. Here we report our preliminary findings related to temporal changes in myocardial perfusion index (MPI). Methods CMR was performed on a Siemens MAGNETOM Verio (Erlangen, Germany) 3.0 Tesla scanner. First-pass myocardial perfusion was assessed by saturation recovery prepared dynamic contrast enhanced sequence during administration of 0.1 mmol/kg of gadoterate meglumine (Dotarem). Semiquantitative analysis was performed on segmented basal and mid-LV short axis slices to derive normalised upslopes of myocardial signal intensity profiles (myocardial perfusion index, MPI). The change in MPI over time was analysed statistically using a linear mixed effects model. Results 13 patients currently have undergone CMR at baseline and during treatment (mean age 66 years, SD: 9; 71% male), 8 patients have undergone CMR at 6 weeks post treatment initiation (5 patients lost to follow-up/ died), and 6 patients have undergone CMR at 6 months from baseline (n = 2 lost to follow-up/ died). Perfusion index (Figure 1) varies significantly with time (p = 0.0015). After adjustment for multiple testing, the increase from baseline is statistically significant at 6 weeks (p = 0.014) and approaches significance at 6 months (p = 0.074) post treatment. Conclusion Change in microvascular perfusion is most pronounced 6 weeks following the completion of treatment. This finding will be used in the design of future clinical studies, where measurement of MPI will provide a robust comparison of different existing and emerging treatment protocols for NSCLC with regard to their effects on myocardial physiology. Funding Beatson Oncology Centre Fund

0083 : Hyperhemia on the first-pass MRI perfusion for the diagnosis of acute myocarditis

MRI is the current way for the diagnosis of acute myocarditis, based on the Lake Louise criteria (presence of at least two of the three following criteria: myocardial edema, hyperaemia and/or a late Gadolinium enhancement). The first-pass perfusion sequence, used for detecting myocardial ischemia, may also be used to highlight a myocardial hyperemia in acute myocarditis. The aim of our study was to assess subepicardial hyperemia, seen on the first pass perfusion sequence by MRI, as a new method for the diagnosis of acute myocarditis. 47 patients (mean age = 42.4±15,6 years; 35 men) with acute myocarditis were included and compared to 16 healthy controls (without heart disease). The first-pass perfusion was evaluated by two blinded observers and compared to myocardial late Gadolinium enhancement, considered the reference method for the diagnosis of acute myocarditis, using both a qualitative (visual analysis) and a semi-quantitative method (ratio of the signals: infarction hyperaemia / healthy myocardium). 24 (51.1%) patients with myocarditis exhibited detectable hyperemia. Qualitative analysis showed good inter-observer variability (kappa = 0.75). There was an increase of the signal intensity in the myocardium with hyperhemia as compared to the adjacent normal myocardium (myocarditis vs controls: 1.08±0.03 vs 0.95±0.05, p=0.03; myocarditis with hyperhemia vs myocarditis non hyperhemia: 1.22±0.04 vs 0.94 ±0.04, p<0.0001). The correlation between the first-pass perfusion and late Gadolinium enhancement was good (kappa = 0,70). Considering the late Gadolinium enhancement as gold standard, the calculated values of sensitivity and specificity were 85% and 94%, respectively. Hyperhemia on the First-pass perfusion sequence, is a valuable and reproducible tool for the diagnosis of acute myocarditis. The author hereby declares no conflict of interest

First pass dual input volume CT-perfusion of lung lesions: The influence of the CT- value range settings on the perfusion values of benign and malignant entities

ObjectiveTo assess the influence of the lower threshold for segmentation of the volume of interest on the perfusion values in first-pass dual input volume CT-perfusion of lung lesions. Materials and methodsDual input maximum slope volume CT-perfusion was performed in 48 patients (mean age±standard deviation [SD], 68±10years; range, 46–87 years) who underwent subsequent CT-guided biopsy to evaluate a lung lesion. Using commercial perfusion software, a lower and upper threshold was set for determination of the CT-value range, which again determined the volume of interest for perfusion calculation. The pulmonary arterial flow (PAF), bronchial arterial flow (BAF), and perfusion index (PI; PAF/(PAF+BAF)) were calculated at following pre contrast CT value range settings: −80 to 150HU (setting 1), −200 to 150HU (setting 2), −300 to 150HU (setting 3), and −500 to 150HU (setting 4). Perfusion parameters were compared between benign (n, 15) and malignant (n, 33) lesions for each setting. Intraobserver- and interobserver reliability were calculated for setting 4. ResultsMedian PAF was significantly higher in malignant lesions than in benign lesions for all settings (53–96 versus 29–62mL/min/100mL, P<0.05). There was no significant difference in BAF between malignant and benign lesions. Median PAF of all lesions was significantly influenced by the CT value range setting (P<0.05), whereas the values increased from setting 1 to 4. Intraobserver analysis as well as interobserver analysis of PAF at setting 4 showed excellent reliability (Cronbach’s alpha 0.98 and 0.95, respectively, P<0.01). ConclusionPAF derived from first-pass dual-input maximum slope volume CT perfusion is statistically significantly higher in malignant than in benign lesion, whereas the measurements are influenced by the lower threshold of the CT value range setting. This has to be considered when using cutoff values provided in the literature for differentiation between benign and malignant lung lesions.

Breathing maneuvers as a coronary vasodilator for myocardial perfusion imaging.

A combined breathing maneuver of hyperventilation, followed by a long voluntary breathhold leads to coronary vasodilation. We investigated the impact of breathing maneuvers on MR first-pass cardiac perfusion imaging and its potential clinical utility. We studied 24 healthy volunteers (37 ± 12 years; 62.5% men) on a clinical 3 Tesla MRI system and performed first-pass perfusion MR at rest, during a short breathhold (S-HVBH) following 60 s of hyperventilation, and at the end of a long breathhold (L-HVBH) following the hyperventilation, performed in random order. A blinded reader analyzed signal intensity upslope, upslope index, and time between 20 and 80% of maximal signal. All volunteers tolerated the breathing maneuvers well and completed the study protocol. The upslope of the signal-intensity-over-time curve was increased during S-HVBH (1.86 ± 0.70 units/s, P < 0.05) and at the end of L-LVBH (1.77 ± 0.82 units/s), when compared with baseline results (1.34 ± 0.58 units/s). Corrected for the arterial input, the upslope was higher at the end of the L-HVBH (0.095 ± 0.019 units/s versus 0.077 ± 0.016 units/s at rest, P < 0.01) as was the myocardial perfusion reserve index (1.25 ± 0.22 versus 1.09 ± 0.17; P < 0.001). In a multiple regression model, only gender, rate-pressure product, and breathhold time were independently and significantly related to the upslope (R = 0.771; P < 0.001). In conclusion, a voluntary long breathhold after hyperventilation leads to an increase of the myocardial perfusion reserve index. This may impact findings from current practice of first-pass perfusion imaging. The clinical utility of breathing maneuvers as a vasodilatory stimulus for first-pass perfusion imaging may warrant further research. J. MAGN. RESON. IMAGING 2016;44:947-955.

Diagnostic Performance of First-Pass Myocardial Perfusion Imaging without Stress with Computed Tomography (CT) Compared with Coronary CT Angiography Alone, with Fractional Flow Reserve as the Reference Standard.

Coronary computed tomography angiography (CCTA) in combination with first-pass CT myocardial perfusion imaging (MPI) has a better diagnostic performance than CCTA alone, compared with invasive coronary angiography as the reference standard. The aim of this study was to investigate the additional diagnostic value of first-pass CT-MPI without stress for detecting hemodynamic significance of coronary stenosis, compared with invasive fractional flow reserve (FFR). We recruited 53 patients with suspected coronary artery disease undergoing both CCTA and first-pass CT-MPI without stress and invasive FFR, and 75 vessels were analyzed. We used the same raw data for CCTA and CT-MPI. First-pass CT-MPI was reconstructed by examining the diastolic signal densities as a bull’s eye map. Invasive FFR <0.8 was considered as positive. On per-vessel analysis, the area under the receiver operating characteristic curve for CCTA plus first-pass CT-MPI and CCTA alone was 0.81 (0.73–0.90) and 0.70 (0.61–0.81), respectively (P = 0.036). CCTA plus first-pass CT-MPI without stress showed 0.73 sensitivity, 0.74 specificity, 0.53 positive predictive value, and 0.87 negative predictive value for detecting hemodynamically significant coronary stenosis. First-pass CT-MPI without stress correctly reclassified 38% of CCTA false-positive vessels as true negative. First-pass CT-MPI without stress combined with CCTA demonstrated excellent diagnostic accuracy, compared with invasive FFR as the reference standard. This technique could complement CCTA for diagnosis of coronary artery disease.

Adiposity Is Associated with Gender-Specific Reductions in Left Ventricular Myocardial Perfusion during Dobutamine Stress.

BackgroundObesity and visceral adiposity are increasingly recognized risk factors for cardiovascular disease. Visceral fat may reduce myocardial perfusion by impairing vascular endothelial function. Women experience more anginal symptoms compared to men despite less severe coronary artery stenosis, as assessed by angiography. Women and men have different fat storage patterns which may account for the observed differences in cardiovascular disease. Therefore, our objective was to evaluate the relationship between visceral adipose tissue distributions and myocardial perfusion in men and women.MethodsVisceral and subcutaneous fat distributions and myocardial perfusion were measured in 69 men and women without coronary artery disease using magnetic resonance imaging techniques. Myocardial perfusion index was quantified after first-pass perfusion with gadolinium contrast at peak dose dobutamine stress.ResultsWe observed inverse relationships between female gender (r = -0.35, p = 0.003), pericardial fat (r = -0.36, p = 0.03), intraperitoneal fat (r = -0.37, p = 0.001), and retroperitoneal fat (r = -0.36, p = 0.002) and myocardial perfusion index. Visceral fat depots were not associated with reduced myocardial perfusion at peak dose dobutamine in men. However, in women, BMI (r = -0.33, p = 0.04), pericardial fat (r = -0.53, p = 0.02), subcutaneous fat (r = -0.39, p = 0.01) and intraperitoneal fat (r = -0.30, p = 0.05) were associated with reduced myocardial perfusion during dobutamine stress.ConclusionsHigher visceral fat volumes are associated with reduced left ventricular myocardial perfusion at peak dose dobutamine stress in women but not in men. These findings suggest that visceral fat may contribute to abnormal microcirculatory coronary artery perfusion syndromes, explaining why some women exhibit more anginal symptoms despite typically lower grade epicardial coronary artery stenoses than men.

An extended 3D whole-heart myocardial first-pass perfusion sequence: alternate-cycle views with isotropic and high-resolution imaging

Background Simultaneously optimising parameters such as LV coverage, image resolution and contrast sensitivity is difficult in first-pass perfusion (FPP). 3D FPP shows potential (1) to improve coverage, but “whole-heart” coverage demands high acceleration forcing compromises such as loss of spatial resolution. 2D FPP shows high diagnostic ability with more slices distributed over alternate-RR cycles (2), relaxing acceleration requirements. This work proposes that 3D FPP could interleave two strategies with different 3D parameters in alternate cycles, in sum approaching the full set of desired FPP properties. This work also aims to improve specificity against artefacts by imaging the same myocardium with two different interleaved 3D scans (distinct from reformatting a single 3D FPP scan). Similar confirmation strategies are often used in CMR, such as repetition with swapped phaseencode direction in late-enhancement imaging.