Reducing motion-correction-induced variability in 82rubidium myocardial blood-flow quantification.
Ontology highlight
ABSTRACT: Background
Clinical use of myocardial blood flow (MBF) and flow reserve (MFR) is increasing. Motion correction is necessary to obtain accurate results but can introduce variability when performed manually. We sought to reduce that variability with an automated motion-correction algorithm.Methods
A blinded randomized controlled trial of two technologists was performed on the motion correction of 100 dynamic 82Rb patient studies comparing manual motion correction with manual review and adjustment of automated motion correction. Inter-rater variability between technologists for MBF and MFR was the primary outcome with comparison made by analysis of the limits of agreement. Processing time was the secondary outcome.Results
Limits of agreements between the two technologists decreased significantly for both MBF and MFR, going from [- 0.22, 0.22] mL/min/g and [- 0.31, 0.36] to [- 0.12, 0.15] mL/min/g and [- 0.15, 0.18], respectively (both P < .002). In addition, the average time spent on motion correcting decreased by 1 min per study from 5:21 to 4:21 min (P = .001).Conclusions
In this randomized controlled trial, the use of automated motion correction significantly decreased inter-user variability and reduced processing time.
SUBMITTER: Poitrasson-Riviere A
PROVIDER: S-EPMC7176539 | biostudies-literature |
REPOSITORIES: biostudies-literature
Similar Datasets
Project description:BackgroundPatient motion can lead to misalignment of left ventricular (LV) volumes-of-interest (VOIs) and subsequently inaccurate quantification of myocardial blood flow (MBF) and flow reserve (MFR) from dynamic PET myocardial perfusion images. We aimed to develop an image-based 3D-automated motion-correction algorithm that corrects the full dynamic sequence for translational motion, especially in the early blood phase frames (~ first minute) where the injected tracer activity is transitioning from the blood pool to the myocardium and where conventional image registration algorithms have had limited success.MethodsWe studied 225 consecutive patients who underwent dynamic rest/stress rubidium-82 chloride (82Rb) PET imaging. Dynamic image series consisting of 30 frames were reconstructed with frame durations ranging from 5 to 80 seconds. An automated algorithm localized the RV and LV blood pools in space and time and then registered each frame to a tissue reference image volume using normalized gradient fields with a modification of a signed distance function. The computed shifts and their global and regional flow estimates were compared to those of reference shifts that were assessed by three physician readers.ResultsThe automated motion-correction shifts were within 5 mm of the manual motion-correction shifts across the entire sequence. The automated and manual motion-correction global MBF values had excellent linear agreement (R = 0.99, y = 0.97x + 0.06). Uncorrected flows outside of the limits of agreement with the manual motion-corrected flows were brought into agreement in 90% of the cases for global MBF and in 87% of the cases for global MFR. The limits of agreement for stress MBF were also reduced twofold globally and by fourfold in the RCA territory.ConclusionsAn image-based, automated motion-correction algorithm for dynamic PET across the entire dynamic sequence using normalized gradient fields matched the results of manual motion correction in reducing bias and variance in MBF and MFR, particularly in the RCA territory.
| S-EPMC6504625 | biostudies-literature
Project description:BackgroundPatient motion can lead to misalignment of left ventricular volumes of interest and subsequently inaccurate quantification of myocardial blood flow (MBF) and flow reserve (MFR) from dynamic PET myocardial perfusion images. We aimed to identify the prevalence of patient motion in both blood and tissue phases and analyze the effects of this motion on MBF and MFR estimates.MethodsWe selected 225 consecutive patients that underwent dynamic stress/rest rubidium-82 chloride (82Rb) PET imaging. Dynamic image series were iteratively reconstructed with 5- to 10-second frame durations over the first 2 minutes for the blood phase and 10 to 80 seconds for the tissue phase. Motion shifts were assessed by 3 physician readers from the dynamic series and analyzed for frequency, magnitude, time, and direction of motion. The effects of this motion isolated in time, direction, and magnitude on global and regional MBF and MFR estimates were evaluated. Flow estimates derived from the motion corrected images were used as the error references.ResultsMild to moderate motion (5-15 mm) was most prominent in the blood phase in 63% and 44% of the stress and rest studies, respectively. This motion was observed with frequencies of 75% in the septal and inferior directions for stress and 44% in the septal direction for rest. Images with blood phase isolated motion had mean global MBF and MFR errors of 2%-5%. Isolating blood phase motion in the inferior direction resulted in mean MBF and MFR errors of 29%-44% in the RCA territory. Flow errors due to tissue phase isolated motion were within 1%.ConclusionsPatient motion was most prevalent in the blood phase and MBF and MFR errors increased most substantially with motion in the inferior direction. Motion correction focused on these motions is needed to reduce MBF and MFR errors.
| S-EPMC6151305 | biostudies-literature
Project description:BackgroundRepositioning of the heart during myocardial perfusion imaging (MPI) using Rubidium-82 (Rb-82) PET may occur when using regadenoson. Our aim was to determine the prevalence and the effect of correcting for this myocardial creep on myocardial blood flow (MBF) quantification.MethodsWe retrospectively included 119 consecutive patients who underwent dynamic rest- and regadenoson-induced stress MPI using Rb-82 PET. The presence of myocardial creep was visually assessed in the dynamic stress PET series by identifying differences between the automatically drawn myocardium contour and the activity. Uncorrected and corrected stress MBFs were compared for the three vascular territories (LAD, LCX, and RCA) and for the whole myocardium.ResultsMyocardial creep was observed in 52% of the patients during stress. Mean MBF values decreased after correction in the RCA from 4.0 to 2.7 mL/min/g (P < 0.001), in the whole myocardium from 2.7 to 2.6 mL/min/g (P = 0.01), and increased in the LAD from 2.5 to 2.6 mL/min/g (P = 0.03) and remained comparable in the LCX (P = 0.3).ConclusionsMyocardial creep is a frequent phenomenon when performing regadenoson-induced stress Rb-82 PET and has a significant impact on MBF values, especially in the RCA territory. As this may hamper diagnostic accuracy, myocardial creep correction seems necessary for reliable quantification.
| S-EPMC6517358 | biostudies-literature
Project description:IntroductionOur aim was to estimate the probability of obstructive CAD (oCAD) for an individual patient as a function of the myocardial flow reserve (MFR) measured with Rubidium-82 (Rb-82) PET in patients with a visually normal or abnormal scan.Materials and methodsWe included 1519 consecutive patients without a prior history of CAD referred for rest-stress Rb-82 PET/CT. All images were visually assessed by two experts and classified as normal or abnormal. We estimated the probability of oCAD for visually normal scans and scans with small (5%-10%) or larger defects (> 10%) as function of MFR. The primary endpoint was oCAD on invasive coronary angiography, when available.Results1259 scans were classified as normal, 136 with a small defect and 136 with a larger defect. For the normal scans, the probability of oCAD increased exponentially from 1% to 10% when segmental MFR decreased from 2.1 to 1.3. For scans with small defects, the probability increased from 13% to 40% and for larger defects from 45% to > 70% when segmental MFR decreased from 2.1 to 0.7.ConclusionPatients with > 10% risk of oCAD can be distinguished from patients with < 10% risk based on visual PET interpretation only. However, there is a strong dependence of MFR on patient's individual risk of oCAD. Hence, combining both visual interpretation and MFR results in a better individual risk assessment which may impact treatment strategy.
| S-EPMC10558363 | biostudies-literature
Project description:BackgroundWe compared quantification of MBF and myocardial flow reserve (MFR) with a 99mTc-sestamibi CZT-SPECT to 15O-water PET.MethodsSPECT MBF for thirty patients in the WATERDAY study was re-analyzed by QPET software with motion correction and optimal placement of the arterial input function. 15O-water PET MBF was re-quantified using dedicated software. Inter-operator variability was assessed using repeatability coefficients (RPC).ResultsSignificant correlations were observed between global (r = 0.91, P < 0.001) and regional MBF (r = 0.86, P < 0.001) with SPECT compared to PET. Global MBF (rest 0.95 vs 1.05 ml/min/g, P = 0.07; stress 2.62 vs 2.68 mL/min/g, P = 0.17) and MFR (2.65 vs 2.75, P = 0.86) were similar between SPECT and PET. Rest (0.81 vs 0.98 mL/min/g, P = 0.03) and stress MBF (1.98 vs 2.61 mL/min/g, P = 0.01) in right coronary artery (RCA) were lower with SPECT compared to PET. However, MFR in the RCA territory was similar (2.54 vs 2.77, P = 0.21). The SPECT-PET RPC for global MBFs and MFR were 0.95 mL/min/g and 0.94, with inter-observer RPC of 0.59 mL/min/g and 0.74, respectively.ConclusionsMBF and MFR derived from CZT-SPECT with motion correction and optimal placement of the arterial input function showed good agreement with 15O-water PET, as well as low inter-operator variability.
| S-EPMC7042031 | biostudies-literature
Project description:BackgroundA variety of temporal sampling protocols is used worldwide to measure myocardial blood flow (MBF). Both the length and number of time frames in these protocols may alter MBF and myocardial flow reserve (MFR) measurements. We aimed to assess the effect of different clinically used temporal sampling protocols on MBF and MFR quantification in Rubidium-82 (Rb-82) PET imaging.MethodsWe retrospectively included 20 patients referred for myocardial perfusion imaging using Rb-82 PET. A literature search was performed to identify appropriate sampling protocols. PET data were reconstructed using 14 selected temporal sampling protocols with time frames of 5-10 seconds in the first-pass phase and 30-120 seconds in the tissue phase. Rest and stress MBF and MFR were calculated for all protocols and compared to the reference protocol with 26 time frames.ResultsMBF measurements differed (P ≤ 0.003) in six (43%) protocols in comparison to the reference protocol, with mean absolute relative differences up to 16% (range 5%-31%). Statistically significant differences were most frequently found for protocols with tissue phase time frames < 90 seconds. MFR did not differ (P ≥ 0.11) for any of the protocols.ConclusionsVarious temporal sampling protocols result in different MBF values using Rb-82 PET. MFR measurements were more robust to different temporal sampling protocols.
| S-EPMC9345838 | biostudies-literature
Project description:BackgroundCoronary microvascular dysfunction has been described in patients with autoimmune rheumatic disease (ARD). However, it is unknown whether positron emission tomography (PET)-derived myocardial flow reserve (MFR) can predict adverse events in this population.MethodsPatients with ARD without coronary artery disease who underwent dynamic rest-stress 82Rubidium PET were retrospectively studied and compared with patients without ARD matched for age, sex, and comorbidities. The association between MFR and a composite end point of mortality or myocardial infarction or heart failure admission was evaluated with time to event and Cox-regression analyses.ResultsIn 101 patients with ARD (88% female, age: 62±10 years), when compared with matched patients without ARD (n=101), global MFR was significantly reduced (median: 1.68 [interquartile range: 1.34-2.05] versus 1.86 [interquartile range: 1.58-2.28]) and reduced MFR (<1.5) was more frequent (40% versus 22%). MFR did not differ among subtypes of ARDs. In survival analysis, patients with ARD and low MFR (MFR<1.5) had decreased event-free survival for the combined end point, when compared with patients with and without ARD and normal MFR (MFR>1.5) and when compared with patients without ARD and low MFR, after adjustment for the nonlaboratory-based Framingham risk score, rest left ventricular ejection fraction, severe coronary calcification, and the presence of medium/large perfusion defects. In Cox-regression analysis, ARD diagnosis and reduced MFR were both independent predictors of adverse events along with congestive heart failure diagnosis and presence of medium/large stress perfusion defects on PET. Further analysis with inclusion of an interaction term between ARD and impaired MFR revealed no significant interaction effects between ARD and impaired MFR.ConclusionsIn our retrospective cohort analysis, patients with ARD had significantly reduced PET MFR compared with age-, sex-, and comorbidity-matched patients without ARD. Reduced PET MFR and ARD diagnosis were both independent predictors of adverse outcomes.
| S-EPMC8475774 | biostudies-literature
Project description:ObjectivesQuantification of myocardial blood flow (MBF) and stress/rest flow reserve is used increasingly to diagnose multi-vessel coronary artery disease and micro-vascular disease with PET imaging. However, variability in the measurements may limit physician confidence to direct revascularization therapies based on specific threshold values. This study evaluated the effects of rubidium-82 (82Rb) tracer injection profile using a constant-activity-rate (CA) vs a constant-flow-rate (CF) infusion to improve test-retest repeatability of MBF measurements.Method22 participants underwent single-session 82Rb dynamic PET imaging during rest and dipyridamole stress using one of 2 test-retest infusion protocols: CA-CA (n = 12) or CA-CF (n = 10). MBF was quantified using a single-tissue-compartment model (1TCM) and a simplified retention model (SRM). Non-parametric test-retest repeatability coefficients (RPCnp) were compared between groups. Myocardium-to-blood contrast and signal-to-noise ratios of the late uptake images (2 to 6 minutes) were also compared to evaluate standard myocardial perfusion image (MPI) quality.ResultsMBF values in the CA-CA group were more repeatable (smaller RPCnp) than the CA-CF group using the 1TCM at rest alone, rest and stress combined, and stress/rest reserve (21% vs 36%, 16% vs 19%, and 20% vs 27%, P < 0.05, respectively), and using the SRM at Rest and Stress alone, Rest and Stress combined, and stress/rest reserve (21% vs 38%, 15% vs 25%, 22% vs 38%, and 23% vs 49%, P < 0.05, respectively). In terms of image quality, myocardium-to-blood contrast and signal-to-noise ratios were not significantly different between groups.ConclusionsConstant-activity-rate 'square-wave' infusion of 82Rb produces more repeatable tracer injection profiles and decreases the test-retest variability of MBF measurements, when compared to a constant-flow-rate 'bolus' administration of 82Rb, especially with SRM, and without compromising standard MPI quality.
| S-EPMC5966478 | biostudies-literature
Project description:BackgroundPET scanners using silicon photomultipliers with digital readout (SiPM PET) have an improved temporal and spatial resolution compared to PET scanners using conventional photomultiplier tubes (PMT PET). However, the effect on image quality and visibility of perfusion defects in myocardial perfusion imaging (MPI) is unknown. Our aim was to determine the value of a SiPM PET scanner in MPI.MethodsWe prospectively included 30 patients who underwent rest and regadenoson-induced stress Rubidium-82 (Rb-82) MPI on the D690 PMT PET (GE Healthcare) and within three weeks on the Vereos SiPM PET (Philips Healthcare). Two expert readers scored the image quality and assessed the existence of possible defects. In addition, interpreter's confidence, myocardial blood flow (MBF), and myocardial flow reserve (MFR) values were compared.ResultsImage quality improved (P = 0.03) using the Vereos as compared to the D690. Image quality of the Vereos and the D690 was graded fair in 20% and 10%, good in 60% and 50%, and excellent in 20% and 40%, respectively. Defect interpretation and interpreter's confidence did not differ between the D690 and the Vereos (P > 0.50). There were no significant differences in rest MBF (P ≥ 0.29), stress MBF (P ≥ 0.11), and MFR (P ≥ 0.51).ConclusionSiPM PET provides an improved image quality in comparison with PMT PET. Defect interpretation, interpreter's confidence, and absolute blood flow measurements were comparable between both systems. SiPM PET is therefore a reliable technique for MPI using Rb-82.Trial registrationToetsingOnline NL63853.075.17. Registered 13 November, 2017.
| S-EPMC8873116 | biostudies-literature
Project description:BackgroundSmall-animal myocardial infarct models are frequently used in the assessment of new cardioprotective strategies. A validated quantification of perfusion using a non-cyclotron-dependent PET tracer would be of importance in monitoring response to therapy. We tested whether myocardial PET perfusion imaging is feasible with Rubidium-82 (82Rb) in a small-animal scanner using a rat myocardial infarct model.Methods18 Sprague-Dawley rats underwent permanent coronary artery ligation (infarct group), and 11 rats underwent ischemia-reperfusion (reperfusion group) procedure. 82Rb-PET and magnetic resonance imaging (MRI) were conducted before and after the intervention. Perfusion was compared to both left ventricle ejection fraction (LVEF) and infarct size assessed by MRI.ResultsFollow-up global 82Rb-uptake correlated significantly with infarct size (infarct group: r = -0.81, P < 0.001 and reperfusion group: r = -0.61, P = 0.04). Only 82Rb-uptake in the infarct group correlated with LVEF. At follow-up, a higher segmental 82Rb-uptake in the infarct group was associated with better wall motion (β = 0.034, CI [0.028;0.039], P < 0.001, R2 = 0.30), and inversely associated with scar transmurality (β = -2.4 [-2.6; -2.2], P < 0.001, R2 = 0.59). The associations were similar for the reperfusion group.Conclusion82Rb-PET is feasible in small animal scanners despite the long positron range and enables fast and time-efficient myocardial perfusion imaging in rat models.
| S-EPMC6517336 | biostudies-literature