Quantitative Myocardial Perfusion with 2D and 3D Sequences Alternating Every Heartbeat

PurposeTo evaluate a myocardial perfusion acquisition that alternates 2D simultaneous multi-slice (SMS) and 3D stack-of-stars (SoS) acquisitions each heartbeat. MethodsA hybrid saturation recovery radial 2D SMS and a saturation recovery 3D SoS sequence were created for the quantification of myocardial blood flow (MBF). Initial studies were done to study the effects of using only every other beat for the 2D SMS in two subjects, and for the 3D SoS in two subjects. Alternating heartbeat 2D SMS and 3D SoS were then performed in ten dog studies at rest, four dog studies at adenosine stress, and two human resting studies. 2D SMS acquisition acquired three slices and 3D SoS acquired six slices. An arterial input function (AIF) for 2D SMS was obtained using the first 24 rays. For 3D, the AIF was obtained in a 2D slice prior to each 3D SoS readout. Quantitative MBF analysis was performed for 2D SMS and 3D SoS separately, using a two-compartment model. ResultsAcquiring every-other-beat data resulted in 5-20% perfusion changes at rest for both 2D SMS and 3D SoS methods. For alternating acquisitions, 2D SMS and 3D SoS quantitative perfusion values were comparable for both the twelve rest studies (2D SMS: 0.68±0.15 vs 3D: 0.69±0.15 ml/g/min, p=0.85) and the four stress studies (2D SMS: 1.28±0.22 vs 3D: 1.30±0.24 ml/g/min, p=0.66).ConclusionEvery-other-beat acquisition changed estimated perfusion values relatively little for both sequences. 2D SMS and 3D SoS gave similar quantitative perfusion estimates when used in an alternating every-other-heartbeat acquisition. Such an approach allows consideration of more diverse perfusion acquisitions that could have complementary features, although testing in a cardiac disease population is needed.

Correlation between quantitative perfusion histogram parameters of DCE-MRI and PTEN, P-Akt and m-TOR in different pathological types of lung cancer

Background To explore if the quantitative perfusion histogram parameters of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) correlates with the expression of PTEN, P-Akt and m-TOR protein in lung cancer. Methods Thirty‐three patients with 33 lesions who had been diagnosed with lung cancer were enrolled in this study. They were divided into three groups: squamous cell carcinoma (SCC, 15 cases), adenocarcinoma (AC, 12 cases) and small cell lung cancer (SCLC, 6 cases). Preoperative imaging (conventional imaging and DCE-MRI) was performed on all patients. The Exchange model was used to measure the phar- macokinetic parameters, including Ktrans, Vp, Kep, Ve and Fp, and then the histogram parameters meanvalue, skewness, kurtosis, uniformity, energy, entropy, quantile of above five parameters were analyzed. The expression of PTEN, P-Akt and m-TOR were assessed by immunohistochemistry. Spearman correlation analysis was used to compare the correlation between the quantitative perfusion histogram parameters and the expression of PTEN, P-Akt and m-TOR in different pathological subtypes of lung cancer. Results The expression of m-TOR (P = 0.013) and P-Akt (P = 0.002) in AC was significantly higher than those in SCC. Vp (uniformity) in SCC group, Ktrans (uniformity), Ve (kurtosis, Q10, Q25) in AC group, Fp (skewness, kurtosis, energy), Ve (Q75, Q90, Q95) in SCLC group was positively correlated with PTEN, and Fp (entropy) in the SCLC group was negatively correlated with PTEN (P < 0.05); Kep (Q5, Q10) in the SCLC group was positively correlated with P-Akt, and Kep (energy) in the SCLC group was negatively correlated with P-Akt (P < 0.05); Kep (Q5) in SCC group and Vp (meanvalue, Q75, Q90, Q95) in SCLC group was positively correlated with m-TOR, and Ve (meanvalue) in SCC group was negatively correlated with m-TOR (P < 0.05). Conclusions The quantitative perfusion histogram parameters of DCE-MRI was correlated with the expression of PTEN, P-Akt and m-TOR in different pathological types of lung cancer, which may be used to indirectly evaluate the activation status of PI3K/Akt/mTOR signal pathway gene in lung cancer, and provide important reference for clinical treatment.

Abstract P334: Multiphase Computed Tomography Angiography-Perfusion for Quantitative Measurement of Ischemic Volumes

Introduction: Proficiency required to execute CT perfusion (CTP) protocols is a limiting factor in its use in acute stroke. We propose to calculate perfusion parametric maps and measure ischemic volumes using readily available non-contrast CT (NCCT) and multiphase CT angiography (mCTA) images. Materials and Methods: Twenty-five patients presenting with acute ischemic stroke were included in this study. Our proposed dynamic sequence (multiphase CT angiography-perfusion, mCTA-P) consisted of the NCCT as the pre-contrast baseline and three phases of mCTA, which corresponded to the peak arterial, peak venous, and late venous phases at 8 s intervals. CTP was acquired after mCTA and consisted of 22 dynamic images acquired over 60 s at 2.8 s intervals. A prototype model-based deconvolution algorithm (CT Perfusion 4D, GE Healthcare) was used to calculate cerebral blood flow (CBF) and Tmax maps for each series. Infarct was classified as voxels that satisfied both a time-dependent relative CBF threshold and Tmax > 8 s while penumbral voxels satisfied either threshold but not both. Results: Median (interquartile range) 24-hour follow-up infarct volume was 18.6 (4.7 to 34.3) ml and median stroke onset-to-CTP time was 124.0 (70.5 to 201.5) min. Bland-Altman analysis revealed good agreement between CTP and mCTA-P volume measurements as mean differences (limits of agreement) were -1.0 (-14.9 to 12.9) ml for infarct and 8.4 (-42.4 to 59.1) ml for penumbra. Intraclass correlation (95% confidence interval, p < 0.05) between CTP and mCTA-P volumes were 0.72 (0.46 to 0.87) for infarct and 0.68 (0.41 to 0.85) for penumbra, indicating good to moderate reliability. Conclusion: Quantitative perfusion can be estimated from NCCT and mCTA without introducing additional scan time, radiation dose, and contrast injections associated with CTP. Our technique allows assessments of early ischemic changes and collaterals to be augmented with quantitative perfusion measurements of ischemic volumes.

Potential application of dynamic contrast enhanced ultrasound in predicting microvascular invasion of hepatocellular carcinoma

OBJECTIVE: To investigate the clinical value of dynamic contrast enhanced ultrasound (D-CEUS) in predicting the microvascular invasion (MVI) of hepatocellular carcinoma (HCC). PATIENTS AND METHODS: In this retrospective study, 16 patients with surgery and histopathologically proved HCC lesions were included. Patients were classified according to the presence of MVI: MVI positive group (n = 6) and MVI negative group (n = 10). Contrast enhanced ultrasound (CEUS) examinations were performed within a week before surgery. Dynamic analysis was performed by VueBox ® software (Bracco, Italy). Three regions of interests (ROIs) were set in the center of HCC lesions, at the margin of HCC lesions and in the surrounding liver parenchyma accordingly. Time intensity curves (TICs) were generated and quantitative perfusion parameters including WiR (wash-in rate), WoR (wash-out rate), WiAUC (wash-in area under the curve), WoAUC (wash-out area under the curve) and WiPi (wash-in perfusion index) were obtained and analyzed. RESULTS: All of HCC lesions showed arterial hyperenhancement (100 %) and at the late phase as hypoenhancement (75 %) in CEUS. Among all CEUS quantitative parameters, the WiAUC and WoAUC were higher in MVI positive group than in MVI negative group in the center HCC lesions (P < 0.05), WiAUC, WoAUC and WiPI were higher in MVI positive group than in MVI negative group at the margin of HCC lesions. WiR and WoR were significant higher in MVI positive group. CONCLUSIONS: D-CEUS with quantitative perfusion analysis has potential clinical value in predicting the existence of MVI in HCC lesions.

Impact of obesity on myocardial microvasculature assessed using fully-automated inline myocardial perfusion mapping CMR

Funding Acknowledgements Type of funding sources: Public Institution(s). Main funding source(s): Guy"s and St Thomas" Charity University College London Hospitals Biomedical Research Centre Background Obesity and cardiovascular disease are associated, but the relationship is poorly understood. Myocardial perfusion, metabolic derangement and lipotoxicity appear adversely associated in many scenarios (myocardial injury, diastolic dysfunction, diabetes). Altered perfusion (by PET) predicts outcome, and it is hypothesised that perfusion derangement is part of causality for cardiac disease and adverse outcomes. Purpose To assess the presence and pattern of myocardial microvascular dysfunction in patients with obesity (scheduled for bariatric surgery) using stress quantitative perfusion mapping. Methods 38 subjects with obesity planned to undergo bariatric surgery and 38 age and sex matched healthy volunteers (no diabetes, no hypertension) underwent anthropometry, biochemistry and CMR at 1.5T (Siemens) with cine imaging, stress (adenosine 140-210 mcg/kg/min) and rest fully-automated quantitative perfusion mapping. Results Bariatric patients had a higher BMI (44 ± 6.4 vs 26.5 ± 4kg/m2 p = 0.001); 58%(22) were diabetic and 58%(22) had hypertension. Bariatric patients had higher absolute but lower indexed end-diastolic volumes, and overall higher ejection fractions (+5%) (see Table). Rest myocardial blood flow (MBF) in bariatric patients was the same (1.00 ± 0.3 vs 0.88 ± 0.24 p = 0.052), but stress perfusion results were significantly lower both for stress MBF (2.35 ± 0.69 vs 2.93 ± 0.76ml/g/min p = 0.001) and myocardial perfusion reserve (MPR 2.48 ± 0.82 vs 3.4 ± 0.81ml/g/min p = 0.0001). Although this was transmural, the endocardial stress MBF was particularly negatively affected in the bariatric cohort compared to controls (endocardial MBF 2.16 ± 0.65 vs 2.82 ± 0.73ml/g/min, p = 0.0001 vs epicardial MBF: 2.52 ± 0.76 vs 3.06 ± 0.79 p = 0.003), meaning there was an increased endo-epicardial stress MBF gradient in bariatric patients (0.87 ± 0.12 vs 0.92 ± 0.07 p = 0.03). Conclusion Compared to healthy controls, patients with obesity have abnormal myocardial stress perfusion with reduced global perfusion, perfusion reserve and an increased transmyocardial perfusion gradient. Table - myocardial perfusion parameters Category Bariatric patients n = 38 Controls n = 38 p value Age (years) 48 ± 11 45 ± 13 0.25 n male (%) 12 (32%) 10 (36%) 0.32 LVEDV (ml) 168 ± 37 149 ± 31 0.017 LVEDVi (ml/m2) 70.4 ± 12.3 78.8 ± 12.1 0.004 LV Mass (g) 116 ± 31 99 ± 28 0.019 EF (%) 70 ± 8 65 ± 5 0.002 LVEDV - left ventricular end-diastolic volume, EF - ejection fraction

Microvascular and mechanical improvements following bariatric surgery in the obese; mechanistic insights from advanced & automated quantitative perfusion cardiac MRI

Funding Acknowledgements Type of funding sources: Public Institution(s). Main funding source(s): Guy"s and St Thomas" Charity University College London Hospital Biomedical Research Centre Background In people with obesity, bariatric surgery reduces mortality, heart failure and coronary disease, improving metabolic (blood sugar, lipid profile, inflammation) and cardiovascular (diastolic/systolic function, filling pressure, cardiac remodelling) parameters. Myocardial microvascular function is a candidate causal link of metabolic to structural cardiac abnormalities. Purpose We hypothesised that bariatric surgery could improve myocardial microvascular and mechanical function in both those with and without diabetes. Methods Before and six months after bariatric surgery, 24 subjects with obesity were assessed with haematology, biochemistry and advanced CMR (cines, vasodilator adenosine stress and rest fully-automated quantitative perfusion mapping, tissue-tracking (CVI42, post processing). Results. Mean age was 49± 12 years, 35%(8) were male, 63%(15), had hypertension, 17 (71%) had diabetes. Surgery resulted in decreases in BMI (44 ± 7 to 34 ± 6 kg/m2 p = 0.0001) and HbA1c (57 ± 16 to 42 ± 9mmol/mol p = 0.0001). EF% and absolute LV end-diastolic volumes remained unchanged, but mass regressed and myocardial contraction fraction (ratio of stroke volume and LV volume) increased (see Table). There were also strain improvements (radial 35 ± 8.8 to 37.3 ± 8.7 %p = 0.029) (circumferential -19.8 ± 2.3 vs -20.7 ± 3% p = 0.017), although longitudinal did not improve (-16.3 ± 3.2 to -15.9 ± 3% p = 0.25). Myocardial perfusion significantly improved (stress myocardial blood flow, MBF 2.35 ± 0.71 to 2.80 ± 0.98 ml/g/min p = 0.008; myocardial perfusion reserve MPR 2.47 ± 0.78 to 2.97 ± 0.95 p = 0.005). Improvement in stress MBF and MPR from pre-operative to post-operative was higher in the non-diabetics (n = 7 (29%)) than the diabetics (n = 17 (71%)) (stress MBF: 1.15 ± 1.00 vs 0.16 ± 0.39ml/g/min p = 0.002) MPR: (1.09 ± 0.73 vs 0.25 ± 0.66 p = 0.011). Conclusion At 6 months, bariatric surgery results in beneficial myocardial remodelling and substantial improvements in myocardial microvascular function. These improvements occur most in those without diabetes suggesting that there may be reversible and irreversible components to microvascular dysfunction. Perfusion and strain variables Variable Pre-op (n = 24) Post-op (n = 24) p-value LVEDV (ml) 163 ± 28 161 ± 29 0.64 EF (%) 70 ± 8 70 ± 7 0.78 Stroke volume (ml) 113 ± 19 111 ± 21 0.6 LV Mass (g) 117 ± 25 103 ± 21 0.001 Myocardial contraction fraction 94 ± 14 105 ± 14 0.001 LVEDV - left ventricular end-diastolic volume, EF - ejection fraction Abstract Figure.

Multyparametric MRI in differential diagnosis of epithelial ovarian tumors

Systematic analysis of publications concerning differential diagnosis of epithelial ovarian tumors has been done. Review includes articles published in MEDLINE, PubMed, Cochrane Collaboration Registry of Controlled Trials over the last 10 years. The objective of this study was to evaluate the ability of MRI with quantitative perfusion (DCE) and diffusion analysis (DWI) for preoperative differential diagnosis of indeterminate ovarian tumors. DCE-MRI parameters and ADC may represent imaging biomarkers for predicting the nature of ovarian tumors. Authors now recommend that for complex cystic or cystic-solid masses, both DWI and DCE MRI are used, if available.