Dynamic SPECT Research Articles

A Novel Quantitative Parameter for Static Myocardial Computed Tomography: Myocardial Perfusion Ratio to the Aorta.

We evaluated the feasibility of myocardial perfusion ratio to the aorta (MPR) in static computed tomography perfusion (CTP) for detecting myocardial perfusion abnormalities assessed by single-photon emission computed tomography (SPECT). Twenty-five patients with suspected coronary artery disease who underwent dynamic CTP and SPECT were retrospectively evaluated. CTP images scanned at a sub-optimal phase for detecting myocardial perfusion abnormalities were selected from dynamic CTP images and used as static CTP images in the present study. The diagnostic accuracy of MPR derived from static CTP was compared to those of visual assessment and conventional quantitative parameters such as myocardial CT attenuation (HU) and transmural perfusion ratio (TPR). The area under the curve of MPR (0.84; 95% confidence interval [CI], 0.76–0.90) was significantly higher than those of myocardial CT attenuation (0.73; 95% CI, 0.65–0.79) and TPR (0.76; 95% CI, 0.67–0.83) (p < 0.05). Sensitivity and specificity were 67% (95% CI, 54–77%) and 90% (95% CI, 86–92%) for visual assessment, 51% (95% CI, 39–63%) and 86% (95% CI, 82–89%) for myocardial CT attenuation, 63% (95% CI, 51–74%) and 84% (95% CI, 80–88%) for TPR, and 78% (95% CI, 66–86%) and 84% (95% CI, 80–88%) for MPR, respectively. MPR showed higher diagnostic accuracy for detecting myocardial perfusion abnormality compared with myocardial CT attenuation and TPR.

Regadenoson versus dipyridamole: Evaluation of stress myocardial blood flow response on a CZT-SPECT camera

BackgroundRegadenoson is a selective adenosine receptor agonist. It is currently unclear if the level of hyperemia differs between stress agents. We compared Myocardial Blood Flow (MBF) and Myocardial Flow Reserve (MFR) response on CZT-SPECT Myocardial Perfusion Imaging (MPI) to evaluate if dipyridamole and regadenoson could induce the same level of hyperemia. Methods228 patients with dynamic CZT-SPECT MPI were retrospectively analyzed (66 patients stressed with regadenoson and 162 with dipyridamole) in terms of MBF and MFR. To rule out confounding factors, two groups of 41 patients were matched for clinical characteristics in a sub-analysis, excluding high cardiovascular risk patients. ResultsOverall stress MBF was higher in regadenoson patients (1.71 ± 0.73 vs. 1.44 ± 0.55 mL·min−1·g−1 for regadenoson and dipyridamole, respectively, p < .05). However, when confounding factors were ruled out, stress MBF (1.57 ± 0.56 vs. 1.61 ± 0.62 mL·min−1·g−1 for dipyridamole and regadenoson, respectively, p = .88) and MFR (2.62 ± 0.77 vs. 2.46 ± 0.76 for dipyridamole and regadenoson, respectively, p = .40) were not different between regadenoson and dipyridamole. ConclusionsOur results suggest that dipyridamole and regadenoson induce equivalent hyperemia in dynamic SPECT with similar stress MBF and MFR in comparable patients.

CRT-700.08 Safety and Feasibility of Dynamic 6-Minute Adenosine Stress Myocardial Perfusion SPECT Imaging in Patients Diagnosed With Severe Aortic Valve Stenosis

CRT-700.08 Safety and Feasibility of Dynamic 6-Minute Adenosine Stress Myocardial Perfusion SPECT Imaging in Patients Diagnosed With Severe Aortic Valve Stenosis

Development of a dedicated 3D printed myocardial perfusion phantom: proof-of-concept in dynamic SPECT

We aim to facilitate phantom-based (ground truth) evaluation of dynamic, quantitative myocardial perfusion imaging (MPI) applications. Current MPI phantoms are static representations or lack clinical hard- and software evaluation capabilities. This proof-of-concept study demonstrates the design, realisation and testing of a dedicated cardiac flow phantom. The 3D printed phantom mimics flow through a left ventricular cavity (LVC) and three myocardial segments. In the accompanying fluid circuit, tap water is pumped through the LVC and thereafter partially directed to the segments using adjustable resistances. Regulation hereof mimics perfusion deficit, whereby flow sensors serve as reference standard. Seven phantom measurements were performed while varying injected activity of 99mTc-tetrofosmin (330–550 MBq), cardiac output (1.5–3.0 L/min) and myocardial segmental flows (50–150 mL/min). Image data from dynamic single photon emission computed tomography was analysed with clinical software. Derived time activity curves were reproducible, showing logical trends regarding selected input variables. A promising correlation was found between software computed myocardial flows and its reference (rho= − 0.98; p = 0.003). This proof-of-concept paper demonstrates we have successfully measured first-pass LV flow and myocardial perfusion in SPECT-MPI using a novel, dedicated, myocardial perfusion phantom.Graphical abstractThis proof-of-concept study focuses on the development of a novel, dedicated myocardial perfusion phantom, ultimately aiming to contribute to the evaluation of quantitative myocardial perfusion imaging applications.

Performance Evaluation of a Preclinical SPECT Scanner with a Collimator Designed for Medium-Sized Animals.

Background Equipped with two stationary detectors, a large bore collimator for medium-sized animals has been recently introduced for dedicated preclinical single-photon emission computed tomography (SPECT) imaging. We aimed to evaluate the basic performance of the system using phantoms and healthy rabbits. Methods A general-purpose medium-sized animal (GP-MSA) collimator with 135 mm bore diameter and thirty-three holes of 2.5 mm diameter was installed on an ultrahigh-resolution scanner equipped with two large stationary detectors (U-SPECT5-E/CT). The sensitivity and uniformity were investigated using a point source and a cylinder phantom containing 99mTc-pertechnetate, respectively. Uniformity (in %) was derived using volumes of interest (VOIs) on images of the cylinder phantom and calculated as [(maximum count − minimum count)/(maximum count + minimum count) × 100], with lower values of % indicating superior performance. The spatial resolution and contrast-to-noise ratios (CNRs) were evaluated with images of a hot-rod Derenzo phantom using different activity concentrations. Feasibility of in vivo SPECT imaging was finally confirmed by rabbit imaging with the most commonly used clinical myocardial perfusion SPECT agent [99mTc]Tc-sestamibi (dynamic acquisition with a scan time of 5 min). Results In the performance evaluation, a sensitivity of 790 cps/MBq, a spatial resolution with the hot-rod phantom of 2.5 mm, and a uniformity of 39.2% were achieved. The CNRs of the rod size 2.5 mm were 1.37, 1.24, 1.20, and 0.85 for activity concentration of 29.2, 1.0, 0.5, and 0.1 MBq/mL, respectively. Dynamic SPECT imaging in rabbits allowed to visualize most of the thorax and to generate time-activity curves of the left myocardial wall and ventricular cavity. Conclusion Preclinical U-SPECT5-E/CT equipped with a large bore collimator demonstrated adequate sensitivity and resolution for in vivo rabbit imaging. Along with its unique features of SPECT molecular functional imaging is a superior collimator technology that is applicable to medium-sized animal models and thus may promote translational research for diagnostic purposes and development of novel therapeutics.

Combination of compressed sensing-based iterative reconstruction and offset acquisition for I-123 FP-CIT SPECT: a simulation study

Objective(s):The purpose of this study was to validate undersampled single-photon emission computed tomography (SPECT) imaging using a combination of compressed sensing (CS) iterative reconstruction (CS-IR) and offset acquisition.Methods:Three types of numerical phantoms were used to evaluate image quality and quantification derived from CS with offset acquisition. SPECT images were reconstructed using filtered back-projection (FBP), maximum likelihood-expectation maximization (ML-EM), CS-IR, and CS-IR with offset acquisition. The efficacy of CS-IR with offset acquisition was examined in terms of spatial resolution, aspect ratio (ASR), activity concentration linearity, contrast, percent coefficient of variation (%CV), and specific binding ratio (SBR).Results:The full widths at half maximum remained unchanged as the number of projections decreased in CS-IR with offset acquisition. Changes in ASRs and linearities of count density were observed for ML-EM and CS-IR from undersampled projections. The %CV obtained by CS-IR with offset acquisition was substantially lower than that obtained by ML-EM and CS-IR. There were no significant differences between the %CVs obtained from 60 projections by CS-IR with offset acquisition and from 120 projections by FBP. Although the SBRs for CS-IR with offset acquisition tended to be slightly lower than for FBP, the SBRs for CS-IR with offset acquisition did not change with the number of projections.Conclusions:CS-IR with offset acquisition can provide good image quality and quantification compared with a commonly used SPECT reconstruction method, especially from undersampled projection data. Our proposed method could shorten overall SPECT acquisition times, which would benefit patients and enable quantification with dynamic SPECT acquisitions.

Reduced acquisition times for measurement of myocardial blood flow with 99mTc-tetrofosmin and solid-state detector SPECT

BackgroundMeasurement of myocardial blood flow (MBF) is feasible using SPECT imaging but the acquisition requires more time than usual. Our study assessed the impact of reducing acquisition times on the accuracy and repeatability of the uptake rate constant (K1). MethodsTwenty-nine patients underwent two rest/stress studies with Tc-99m-tetrofosmin 18 ± 13 days apart, using a one-day rest/stress dynamic SPECT imaging protocol with a solid-state cardiac camera. A 5-minute static image was acquired prior to tracer injection for subtraction of residual activity, followed immediately by 11-minute of list-mode data collection. Static image acquisition times of 0.5, 1, and 3 minutes and dynamic imaging times of 5, 7, and 9 minutes were simulated by truncating list-mode data. Images were reconstructed with/without attenuation correction and with/without motion correction. Kinetic parameters were calculated using a 1-tissue-compartment model. ResultsK1 increased with reduced dynamic but not static imaging time (P < 0.001). The increase in K1 for a 9-minute scan was small (4.7 ± 5.3%) compared with full-length studies. The repeatability of K1 did not change significantly (13 ± 12%, P > 0.17). ConclusionsA shortened imaging protocol of 3-minute (rest) or 30-second (stress) static image acquisition and 9 minutes of dynamic image acquisition altered K1 by less than 5% compared to a previously validated 11-minute acquisition.

Design Study of an Ultrahigh Resolution Brain SPECT System Using a Synthetic Compound-Eye Camera Design With Micro-Slit and Micro-Ring Apertures.

In this paper, we discuss the design study for a brain SPECT imaging system, referred to as the HelmetSPECT system, based on a spherical synthetic compound-eye (SCE) gamma camera design. The design utilizes a large number ( ~500) of semiconductor detector modules, each coupled to an aperture with a very narrow opening for high-resolution SPECT imaging applications. In this study, we demonstrate that this novel system design could provide an excellent spatial resolution, a very high sensitivity, and a rich angular sampling without scanning motion over a clinically relevant field-of-view (FOV). These properties make the proposed HelmetSPECT system attractive for dynamic imaging of epileptic patients during seizures. In ictal SPECT, there is typically no prior information on where the seizures would happen, and both the imaging resolution and quantitative accuracy of the dynamic SPECT images would provide critical information for staging the seizures outbreak and refining the plans for subsequent surgical intervention.We report the performance evaluation and comparison among similar system geometries using non-conventional apertures, such as micro-ring and micro-slit, and traditional lofthole apertures. We demonstrate that the combination of ultrahigh-resolution imaging detectors, the SCE gamma camera design, and the micro-ring and micro-slit apertures would offer an interesting approach for the future ultrahigh-resolution clinical SPECT imaging systems without sacrificing system sensitivity and FOV.

Capabilities of Modern Semiconductor Gamma Cameras in Radionuclide Diagnosis of Coronary Artery Disease.

This paper presents a review of the literature concerning the clinical application of modern semiconductor (CZT) gamma cameras in the radioinuclide diagnosis of coronary artery disease. It contains information on the diagnostic efficacy of myocardial perfusion studies performed with those cameras compared with the widely used scintillation (Anger) cameras, an overview of their effectiveness in comparison with coronary angiography (also fractional flow reserve) and currently available clinical results of a myocardial flow reserve measured with a dynamic SPECT study. Introduction of this imaging modality to the measurement of a myocardial flow reserve aims to facilitate access to this type of study compared to the less available and more expensive PET method used so far.

Three-dimensional semiquantitative analysis of gastric emptying SPECT.

We used dynamic single-photon emission computed tomography (D-SPECT) to overcome the interference of the planar dynamic imaging due to the overlap of internal organs, thus more accurate physiological function can be obtained. 3D printed gastric phantom was used to simulate gastric emptying (GE). First, the planar dynamic liquid GE procedure was used and served as the reference value; second, D-SPECT followed by repeated liquid GE procedures with three gamma cameras were used. The emptying flow rate of the gastric phantom simulated three flow rates of liquid, semisolid and solid. Third, we simulated the intestinal activity that interfered with the residual value obtained by 2D dynamic imaging, which was compared with D-SPECT. Then, we brought the 3D VOI data into the postprocessing program to obtain the residual activity curve and residual percentage. The residual amount obtained in the phantom at 60th minutes in the first stage is 14.57%; the residual amount of liquid emptying are Siemens: 3.33%, GE: 15.06%, PHILIPS: 1.12%; residual amount for semisolid are Siemens: 47.36%, GE: 54.25%, PHILIPS: 51.57%; residual amount for solids are Siemens: 63.98%, GE: 66.88%, PHILIPS: 63.76%. All values are within the normal range. Then, we simulated the intestinal activity that interfered with the residual value obtained by 2D dynamic imaging: 75-90 min: 10.42, 19.48, 19.51 and 11.02%; however, the residual values obtained with 3D SPECT VOI data: 75-90 min: 1.42, 1.41, 1.35 and 1.02%. These results show that the emptying data errors caused by intestinal overlap can be effectively corrected (P = 0.017). D-SPECT imaging can overcome the interference in the semiquantitative data of residual GE caused in 2D mode.

Measuring SPECT myocardial blood flow at the University of Ottawa Heart Institute

The introduction of new cardiac SPECT cameras has made it practical to do dynamic SPECT imaging and opened the door to performing myocardial blood flow (MBF) imaging with SPECT. In this paper, we describe in detail our approach to dynamic SPECT MBF imaging using a multi-pinhole cardiac SPECT camera and commercially available kinetic analysis software. We use a 1-day rest/stress protocol with 370 MBq injected at rest and 1,000 MBq at stress with a 1- to 2-hour interval between rest and stress imaging. The tracer is injected mechanically over 30 seconds using a syringe pump. Projection data are acquired in listmode for a duration of 11 minutes and then reframed into a dynamic series. Each image is reconstructed independently using vendor-supplied software. The dynamic images are corrected for residual activity and manually corrected for motion using rigid-body translation. The uptake rate constant, K1, is calculated using a 1-tissue-compartment kinetic model and converted to MBF using a previously determined extraction fraction correction.

The feasibility of SPECT CZT measurement of myocardial blood flow and reserve in patients with acute coronary syndrome: comparison with cardiac magnetic resonance

Abstract Funding Acknowledgements Type of funding sources: None. Background. Myocardial infarction with non-obstructive coronary arteries (MINOCA) is currently of interest in terms of diagnostic and treatment strategy. The diagnosis of MINOCA has been included in the STEMI guidelines of the European Society of Cardiology. However, there is lack of data regarding the relationship between myocardial damage according to cardiac magnetic resonance (CMR) and myocardial blood flow (MBF), myocardial flow reserve (MFR) obtained by dynamic SPECT. Purpose. To elucidate impairment of myocardial perfusion, MBF and MFR in patients with MINOCA. Methods. The study included 31 patients (21 men, age 62(56;70) years) with ASC. According to electrocardiography, cardiac biomarkers, invasive coronary angiography two groups were identified: with non-obstructive coronary arteries MINOCA (n = 10); MICAD (n = 21). Within 7-14 days after admission to the hospital all patients underwent dynamic SPECT on CZT gamma-camera with the assessment of standard indices of myocardial perfusion (SSS, SRS, SDS) and quantitative parameters (stress/rest myocardial blood flow (s/r MBF), myocardial flow reserve (MFR)). All patients underwent CMR with late gadolinium enhancement as well. Infarct size (IS), microvascular obstruction (MVO) and myocardial edema size (ME) were evaluated. Results. SSS and SRS differed significantly (p &amp;lt; 0.05) in MINOCA and MICAD patients: MINOCA: SSS 5.0(3.0;5.0), SRS 2.0(1.0;3.0); MICAD: SSS 9.0(5.0;13.0), SRS 6.0(3.0;11.0). However, SDS did not differ significantly in these two groups 2.5(1.0;4.0) vs 4.0(2.0;5.0). Moreover MINOCA patients in comparison with those with MIACD had higher values of quantitative parameters (p &amp;lt; 0.05): sMBF 2.02 (1.71;2.37) vs 0.86 (0.72;1.02) ml/min/g, rMBF 0.68 (0.66;0.86) vs 0.49 (0.4;0.57) ml/min/g, MFR 2.61 (2.23;3.14) vs 1.67 (1.1;1.9), respectively. Based on CMR, a total of 93 left ventricular vessel territories were analyzed. A total of 36(39%) vessel territories were considered as having acute myocardial injury (5 in MICAD, 31 in MINOCA). In patients with MICAD the values of IS, ME were significantly higher as compared to those with MINOCA (IS: 19.4(10.4;29.7)% vs1.8(0.0;6.9)%, ME: 19.5(12.0;30.0)% vs 3.0(0.0;12.0)% - p &amp;lt; 0.01). Based on regional analysis sMBF and MFR were significantly lower in vessel territories considering as CMR positive compared to those without MR signs of myocardial injury: regional sMBF 0.98(0.73;1.79) vs 1.33(0.94;2.08); regional MFR 0.58(0.43;0.9) vs 0.71(0.57;0.88), respectively. Conclusion. SPECT CZT is feasible in identifying both global and regional disturbances of myocardial blood flow and reserve in patients with acute coronary syndrome. MINOCA patients are characterized by mild reduction of myocardial blood flow and perfusion assessed visually and quantitatively. Therefore despite the absence of obstructive coronary artery lesion this group of patients has more pronounced risk of cardiac events and need more aggressive observation and treatment.

Ischemia and No Obstructive Coronary Artery Disease and Pulmonary Hypertension in a 16-Year-Old Girl with Unquenched Hyperthyroidism of Graves' Disease.

A combination of myocardial and pulmonary hypertension was reported in a neonate with Graves’ disease.1 However, neither ischemia and no obstructive coronary artery (INOCA) nor pulmonary hypertension was invasively investigated by single-photon emission computed tomography (SPECT) or right heart catheterization in pediatric patients with Graves’ disease. We reported a 16-year-old girl with unnoticed/untreated Graves’ disease, presenting with exertional dyspnea and cyanosis, undergoing chest radiogram, echocardiography with Doppler, right heart catheterization, coronary angiography, 201thallium-SPECT, and 99mtechnetium-sestamibi dynamic SPECT with myocardial blood flow quantitation, INOCA and pulmonary hypertension due to coronary and pulmonary microvascular dysfunction was diagnosed. We highlight using dynamic SPECT with myocardial blood flow quantitation and right heart catheterization to track down microvascular dysfunction as a culprit of concurrence of INOCA and pulmonary hypertension in patients with Graves’ disease and unquenched hyperthyroidism. The pathogenesis of pulmonary hypertension and INOCA will be discussed.

Automatic quantification package (Hone Graph) for phantom-based image quality assessment in bone SPECT: computerized automatic classification of detectability.

We previously developed a custom-design thoracic bone scintigraphy-specific phantom ("SIM2 bone phantom") to assess image quality in bone single-photon emission computed tomography (SPECT). We aimed to develop an automatic assessment system for imaging technology in bone SPECT and demonstrate the validity of this system. Four spherical lesions of 13-, 17-, 22-, and 28-mm diameters in the vertebrae of SIM2 bone phantom simulating the thorax were filled with radioactivity (target-to-background ratio: 4). Dynamic SPECT acquisitions were performed for 15min; reconstructions were performed using ordered subset expectation maximization at 3-15-min timepoints. Consequently, 216 lesions (54 SPECT images) were obtained: 120 and 96 lesions were used for software development and validation, respectively. The developed software used statistical parametric mapping to rigidly register and automatically calculate quantitative indexes (contrast-to-noise ratio, % coefficient of variance, % detectability equivalence volume, recovery coefficient, target-to-normal bone ratio, and full width at half maximum). A detectability score (DS) was used to define the four observation types (4, excellent; 3, adequate; 2, average; 1, poor) to score hot spherical lesions. The gold standard for DSs was independently classified by three experienced board-certified nuclear medicine technologists using the four observation types; thereafter, a consensus regarding the gold standard for DSs was reached. Using 120 lesions for development, decision tree analysis was performed to determine DS based on the quantitative indexes. We verified the validation of the quantitative indexes and their threshold values for automatic classification using 96 lesions for validation. The trends in the automatically calculated quantitative indices were consistent. Decision tree analysis produced four terminal groups; two quantitative indexes (% detectability equivalence volume and contrast-to-noise ratio) were used to classify DS. The automatically classified DSs exhibited an almost perfect agreement with the gold standard. The percentage agreement and kappa coefficient were 91.7% and 0.93, respectively, in 96 lesions for validation. The developed software automatically classified the detectability of hot lesions in the SIM2 bone phantom using the automatically calculated quantitative indexes, suggesting that this software could provide a means to automatically perform detectability analysis after data input that is excellent in reproducibility and accuracy.

Comparison of empagliflozin and sitagliptin therapy on myocardial perfusion reserve in diabetic patients with coronary artery disease.

Sodium-glucose co-transporter 2 inhibitors reduce the risk of cardiovascular events in type 2 diabetic patients with coronary artery disease (CAD); however, the underlying mechanisms remain unclear. We compared the effects of empagliflozin vs. sitagliptin therapy on myocardial perfusion reserve (MPR) using dynamic single-photon emission computed tomography (SPECT) imaging. In total, 100 patients with type 2 diabetes, CAD and an MPR <2.5 were randomized to receive either empagliflozin (10 mg once daily) or sitagliptin (100 mg once daily). Dynamic SPECT examinations were performed at baseline and at 6 months. The primary endpoint was the percent change of global MPR. Evaluable SPECT data were available for 98 patients. Baseline clinical characteristics and SPECT data were well balanced between the two groups. At a 6-month follow-up, the fasting glucose and glycated hemoglobin levels significantly decreased in both groups. Hematocrit and hemoglobin levels significantly increased in the empagliflozin group but not in the sitagliptin group. The global MPR significantly improved after treatment in both groups (34.5 ± 70.6%; P = 0.005 for empagliflozin vs. 22.4 ± 45.7%; P = 0.024 for sitagliptin). However, there was no significant difference in the global MPR between the two groups (P = 0.934). Similar findings were detected with regard to the regional MPR. Among patients with type 2 diabetes and CAD, both empagliflozin and sitagliptin significantly improved the global MPR with no significant difference between the groups.

Functional transition: Inconsistently parallel to the increase in future liver remnant volume after preoperative portal vein embolization.

BACKGROUNDPreoperative portal vein embolization (PVE) is a widely used strategy to enable major hepatectomy in patients with insufficient liver remnant. PVE induces hypertrophy of the future liver remnant (FLR) and a shift of the functional reserve to the FLR. However, whether the increase of the FLR volume (FLRV) corresponds to the functional transition after PVE remains unclear.AIMTo investigate the sequential relationship between the increase in FLRV and functional transition after preoperative PVE using 3-dimensional (3D) computed tomography (CT) and 99mTc-galactosyl-human serum albumin (99mTc-GSA) single-photon emission computed tomography (SPECT) fusion images. METHODSThirty-three patients who underwent major hepatectomy following PVE at the Department of Gastroenterological Surgery I, Hokkaido University Hospital between October 2013 and March 2018 were enrolled. Three-phase dynamic multidetector CT and 99mTc-GSA SPECT scintigraphy were performed at pre-PVE, and at 1 and 2 wk after PVE; 3D 99mTc-GSA SPECT CT-fused images were constructed from the Digital Imaging and Communications in Medicine data using 3D image analysis system. Functional FLRV (FFLRV) was defined as the total liver volume × (FLR volume counts/total liver volume counts) on the 3D 99mTc-GSA SPECT CT-fused images. The calculated FFLRV was compared with FLRV.RESULTSFFLRV increased by a significantly larger extent than FLRV at 1 and 2 wk after PVE (P < 0.01). The increase in FFLRV and FLRV was 55.1% ± 41.6% and 26.7% ± 17.8% (P < 0.001), respectively, at 1 wk after PVE, and 64.2% ± 33.3% and 36.8% ± 18.9% (P < 0.001), respectively, at 2 wk after PVE. In 3 of the 33 patients, FFLRV levels decreased below FLRV at 2 wk. One of the three patients showed rapidly progressive fatty changes in FLR. The biopsy at 4 wk after PVE showed macro- and micro-vesicular steatosis of more than 40%, which improved to 10%. Radical resection was performed at 13 wk after PVE. The patient recovered uneventfully without any symptoms of pos-toperative liver failure.CONCLUSIONThe functional transition lagged behind the increase in FLRV after PVE in some cases. Evaluating both volume and function is needed to determine the optimal timing of hepatectomy after PVE.

Dynamic SPECT with assessment myocardial blood flow and coronary flow reserve in MINOCA patients: comparison with cardiac magnetic resonance

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): grant of the President of the Russian Federation Background. In recent years a group of patients with acute myocardial infarction without obstructive coronary artery disease (MINOCA) is of interest. In this group of patients, there is a lack of information related to myocardial perfusion, blood flow and reserve, which could be important in term of risk and prognosis assessment. Purpose. To assess the global and regional myocardial blood flow and coronary flow reserve impairment in MINOCA patients compared to cardiac magnetic resonance (CMR). Methods. The study group comprised 28 patients (18 male, mean 62.9 ± 10.7years) with acute coronary syndrome. Based on ICA results all patients were divided into two groups: 1) MINOCA (n = 11); 2) patients with myocardial infarction with obstructive CAD (MICAD) (n = 17). A total of 12/17 (71%) MICAD patients underwent PCI with stenting; in 2/12 cases two arteries were revascularized. Within 7-10 days after admission to the hospital all patients underwent SPECT myocardial perfusion scintigraphy (MPS) with the assessment of standard indices (SSS, SRS, SDS) and quantitative parameters: rest MBF (rMBF), stress MBF (sMBF) and CFR (on CZT gamma-camera). Also, all patients underwent CMR with evaluation of infarct size (IF), microvascular obstruction (MVO), size of myocardial edema (ME) and transmural extent of myocardial infarction (TE). Results Visual analysis showed that SSS differed significantly (p = 0.001) among MINOCA and MICAD groups: 5 (3;6) vs 10 (5;13), respectively. According to the quantitative MPS data analysis, global sMBF and CFR values were significantly higher in MINOCA than in MICAD patients group: 1.2 (0.82;1.69) ml/min/g vs 0.62 (0.52;0.9) ml/min/g; 1.96 (1.23;2.42) vs 1.16 (0.98;1.64) , respectively. CMR indices such as IS, ME and TE were significantly lower in MINOCA compared to MICAD patients: 1.6 (0;7.8) vs 14.8 (6.3;22.6)%; 8(0;14) vs 18.5 (10;23)%; 0 (0;5) vs 18 (10;25), respectively. Seven(40%) MICAD group patients showed MVO, whereas there were no such patients in MINIOCA group. The regional analysis revealed that sMBF and CFR were significantly lower in LV regions characterized by myocardial injury compared to non-injured regions (based on CMR data): 0.78 (0.51;0.94) ml/min/g vs 1.11 (0.82;1.4) and 1.22 (0.91;1.74) vs 1.52 (1.14;2.42), respectively. Also, we found out significant correlation between regional quantitative SPECT indices and transmural extent of myocardial infarction evaluated by CMR: r=–0.4 for sMBF; r=–0.35 for CFR (p &amp;lt; 0.05). Conclusion. The analysis of quantitative MPS SPECT parameters showed that such approach allows identifying MBF and CFR disturbances both on global and regional level. These results showed that MINOCA patients characterized by mild reduction of myocardial blood flow and perfusion assessed visually and quantitatively. It means that despite the absence of obstructive coronary artery lesion this group of patients has more pronounced risk of cardiac events and need more aggressive observation and treatment.

The usage CZT SPECT to assess myocardial blood flow and flow reserve in myocardial infarction with non-obstructive coronary arteries patients

Abstract Funding Acknowledgements Type of funding sources: None. Background. Myocardial infarction (MI) with non-obstructive coronary arteries (MINOCA) is currently of interest in terms of a small amount of data related to myocardial perfusion, myocardial blood flow (MBF) and myocardial flow reserve (MFR). Purpose. To assess the severity of myocardial perfusion, MBF and MFR impairment in MINOCA patients in comparison to those with MI with obstructive coronary artery disease (MICAD) and non-obstructive stable coronary artery disease (SCAD). Methods. The study group comprised 40 patients (29 men, mean age 62.9 ± 10.7 years). 28 patients were admitted to the hospital due to the acute coronary syndrome. At admission all patients underwent invasive coronary angiography (ICA) and cardiac biomarkers – Creatine phosphokinase-MB (CPK-MB) and Troponin I (TnI) measurement. Two groups of patients were created based on ICA results: 1) MINOCA: with coronary artery stenosis &amp;lt;50%, n = 11; 2) MICAD: with coronary artery stenosis ≥50%, n = 17. SCAD patients group without obstructive atherosclerosis was retrospectively selected from the hospital database. All patients underwent dynamic SPECT on Cadmium-Zinc-Telluride (CZT) gamma camera with the assessment of semi-quantitative indexes of myocardial perfusion (SSS, SRS, SDS) and quantitative parameters (rest MBF (rMBF), stress MBF (sMBF) and MFR). Results. After 24 hours cardiospecific biomarkers levels in MINOCA group were significantly (p &amp;lt; 0.05) lower compared to MICAD group: CPK-MB 21.5 (13.7;45.0) vs. 94.4 (53.1;217.0) U/L; TnI 0.5 (0.1;3.3) vs. 9.8 (2.0;23.0) ng/ml. Standard myocardial perfusion indexes differed significantly (p &amp;lt; 0.05) among all three groups (except SDS between the first and second groups): MINOCA: SSS 5.0 (3.0;6.0), SDS 2.0 (1.0;3.0); MICAD: SSS 9.0 (5.0;13.0), SDS 3.0 (2,0;5.0); SCAD: SSS 1.5 (0.5;2.0), SDS 0.0 (0.0;2.0). Moreover, sMBF and MFR differed significantly in all three groups of patients: MINOCA: sMBF 1.2 (0.8;1.7) ml/min/g, MFR 2.0 (1.2;2.4); MICAD: sMBF 0.7 (0.6;1.0) ml/min/g, MFR 1.2 (1.1;1.5); control group: sMBF 2.2 (2.1;2.3) ml/min/g, MFR 2.6 (2.5;2.8). In 7/11 (64%) of MINOCA patients the value of sMBF was ≤1.5 ml/min/g. In the MICAD group 16/17 (94%) had sMBF ≤1.5 ml/min/g and all SCAD patients had sMBF &amp;gt;1.5 ml/min/g. In 4/11 (36%) of MINOCA patients MFR values were less than 2; in MICAD group MFR &amp;lt; 2 was observed in 15/17 (88%) patients. Conclusion. MINOCA patients have more severe myocardial perfusion abnormalities, lower MBF and MFR compared to those with stable CAD. It means that MINOCA patients may have other reasons for reduced myocardial blood flow, such as endothelial dysfunction, thrombophilia, etc., despite the absence of obstructive coronary artery lesion. Further studies are needed to assess added diagnostic and prognostic value of CZT SPECT derived myocardial flow indexes in MINOCA patients.

Diagnostic efficiency of quantification of myocardial blood flow and coronary flow reserve with CZT dynamic SPECT imaging for patients with suspected coronary artery disease: a comparative study with traditional semi-quantitative evaluation.

Myocardial blood flow (MBF) quantitation with cadmium-zinc-telluride (CZT) dynamic single-photon emission computed tomography (SPECT) is being increasingly investigated toward clinical utilization. In this prospective study, forty-nine patients with suspected or known coronary artery disease (CAD) underwent a rest/adenosine triphosphate (ATP) stress dynamic and routine gated myocardial perfusion imaging (MPI) by CZT SPECT and then received coronary angiography (CAG). Quantitative diagnosis from the dynamic SPECT and a flow diagram was automatically obtained by the dedicated software and compared with the result of semi-quantitative analysis with gated MPI using the angiographic stenosis as the reference standard. When stenosis ≥50% was considered at the participant level, the sensitivity (SN), specificity (SP), positive predictive value (PPV), negative predictive value (NPV) and accuracy (AC) of the quantitative diagnosis were higher than semi-quantitative method as (84.4% vs. 65.6%, 88.2% vs. 70.6%, 93.1% vs. 80.8%, 75.0% vs. 52.2%, 85.7% vs. 67.3%) (all P<0.05). The receiver operating characteristic (ROC) curve analysis generated the optimal critical value as 1.86 and 1.61 mL/min/g for stress MBF (sMBF) and MFR, respectively. The diagnosis performance of the quantitative diagnosis was higher than semi-quantitative method as (78.9% vs. 68.4%, 63.3% vs. 60.0%, 57.7% vs. 52.0%, 82.6% vs. 75.0%, 69.4% vs. 63.3%) for the criteria of ≥75% stenosis on CAG (all P<0.05) with optimal critical values as 1.71 and 1.15 mL/min/g. There was no significant difference between sMBF and MFR. The diagnostic efficiency by using the quantitative method of CZT dynamic SPECT imaging is superior to traditional semi-quantitative gated MPI for the diagnosis of CAD, which improved the diagnostic specificity and accuracy when the critical was stenosis ≥50%.

Realistic Kidney Simulation for the Development of Renal Function Diagnostics by Dynamic SPECT Imaging

Abstract Dynamic SPECT imaging captures the dynamic process of the radioisotope washed in and out, to and from tissues and exchanged between biological compartments. One of the most common application field for dynamic SPECT imaging is investigating renal functions. The main goal of this study was to create realistic simulations of the kidney in order to support the development of dynamic SPECT reconstruction algorithms. We created and parametrized a compartment model of the kidney for simulating the dynamic behavior of the MAG3 radiopharmacon. Solving the model with a parameter set corresponding to the normal and to the pathological cases the SPECT data acquisition was simulated using the GATE Monte Carlo simulation toolkit.