Characteristics of cerebral hemodynamics assessed by ct. However, it remains unclear whether quantitative values generated by this method are more accurate than those generated using optimized deconvolution algorithms of other software packages. Tracer delayinsensitive algorithm can improve reliability of ct perfusion imaging. Comparison of delay sensitive and delay insensitive computed tomography perfusion methods in acute ischemic stroke and their variability according to location of critical vascular stenosis. Ct perfusion maps have low resolution and small infarcts can be easily missed. Comparison of perfusion ct software to predict the final.
In contrast to package a, rapid uses a delayinsensitive algorithm. Effect of extended ct perfusion acquisition time on. Computed tomography perfusion imaging may be considered medically necessary to select patients with anterior largevessel stroke for mechanical embolectomy within 24 hours of symptom onset. After intravascular injection of a contrast agent, computed tomography ct images covering the tissue of interest are taken in quick succession to assess temporal changes in tissue attenuation. Perfusion ct pct processing involves deconvolution, a mathematical operation that computes the perfusion parameters from the pct time density curves and an arterial curve. New software or applications are developed to improve feasibility of ctperfusion with independence ct machine or individual correction after acquisition. Ischemic core was defined as reduction in cbf to ct brain perfusion 2d. Perfusion computed tomography and perfusion weighted magnetic resonance imaging are used to evaluate the extent of the area with ischemic penumbra. Concurrent display of the image maps aid in the assessment of the type and extent of cerebral perfusion disturbances. We aim to assess differences in volumetric and perfusion characteristics in these regions compared to areas. Second, although the parameter of ct perfusion reflects hemodynamics, all commercial programs had delay induced errors andor insufficient correlations with true values, and we have to interpret the accuracy and characteristics of the ct perfusion analysis software for analyzing cerebral hemodynamics. Borst j, marquering ha, beenen lfm, berkhemer oa, dankbaar jw, riordan aj, et al. Timedependent computed tomographic perfusion thresholds for. Stroke assessment varies depending on ct perfusion software.
Also, it can be difficult to determine if a small area of abnormal perfusion represents artefact or infarct. Brain ct perfusion package philips healthcare, the netherlands, extended brilliance workspace, version 3. Susceptibility of tmax to tracer delay on perfusion analysis. Different ct perfusion algorithms in the detection of. To design a digital phantom data set for computed tomography ct perfusion and perfusion weighted imaging on the basis of the widely accepted tracer kinetic theory in which the true values of cerebral blood flow cbf, cerebral blood volume cbv, mean transit time mtt, and tracer arrival delay are known and to evaluate the accuracy and reliability of postprocessing programs using. For each study, the arterial input function was manually selected from the basilar artery or contralateral ica using a 2 voxel. It has recently been reported that commercial software packages using delaysensitive deconvolution algorithms can overestimate penumbraand, hence, final infarct volumewhereas penumbra estimated with delayinsensitive software may better correlate with final infarct volume 12,14. Comparison of three commonly used ct perfusion software. A admission ctcbv map processed using firstgeneration delaysensitive software shows a large right mca territory low blood volume lesion white outline. Rapid is a fully automated software package that uses a delay insensitive algorithm. Tracer delaysensitive perfusion algorithms in ct perfusion ctp result in an. Comparison of delaysensitive and delayinsensitive computed. The impact on medicine could reduce healthcare costs by eliminating some hospital stays, cutting the number of tests and speeding patient diagnosis.
Jan 23, 2012 the next big advancement in cardiac imaging is likely to be computed tomography ct perfusion imaging. Characteristics of misclassified ct perfusion ischemic. Two postprocessing software programs were used to evaluate the effect of aif placement on perfusion parameters using a delay insensitive deconvolution method compared with a standard deconvolution method. Delay sensitive and delay insensitive deconvolution perfusion ct. In this software, 3 types of deconvolution algorithms were implemented. Persistent benign oligemia causes ct perfusion mismatch in. In diagnosing delayed cerebral ischemia dci after aneurysmal subarachnoid hemorrhage asah, delayed arrival of contrast due to vasospasm may also overestimate the extent of ischemia. Background ct perfusion ctp is used to estimate the extent of ischemic core and penumbra in patients with acute ischemic stroke. Introduction tracer delaysensitive perfusion algorithms in ct perfusion ctp result in an overestimation of the extent of ischemia in thromboembolic stroke. Lesion maps, which overlays areas of computerdetected abnormally elevated mean transit time mtt and.
From that date, a limited number of experiences have been carried out to achieve the technique that is now becoming more familiar thanks to the availability of commercial ctp software platforms that are integrated into todays clinical reporting workstations. It is difficult to determine the accuracy and reliability of each program. Ct perfusion imaging in acute stroke radiology key. Sasaki m, kudo k, ogasawara k, fujiwara s 2009 tracer delayinsensitive algorithm can improve reliability of ct perfusion imaging for cerebrovascular stenoocclusive disease. We performed acute and followup ct perfusion scans over the first 3 months after ischemic stroke to investigate disturbances of the bloodbrain barrier bbb and cerebral perfusion in patients with lacunarsubcortical lesions compared to those with cortical lesions alone. Rapid is a fully automated software package that uses a delayinsensitive algorithm. This enables one commonly available modality to image both the detailed anatomy and function of the heart at the same time. Differences in ct perfusion summary maps for patients with.
Three different types of processing software were used to analyze all ctp data. Ct perfusion acquisition optimization is critical for appropriate postprocessing. Tracer delayinsensitive algorithm can improve reliability. Perfusion data were analyzed using an opensource software. Differences in ct perfusion maps generated by different commercial software. The arterial input function was manually selected from the basilar artery or internal carotid artery. Ct perfusion color maps using software a delay insensitive technique obtained with arterial input function aif 1 and aif 2 show qualitative differences, although to lesser degree, that are similar to those shown using software b. Differences in ct perfusion summary maps for patients with acute.
Differences in ct perfusion maps generated by different. We investigated whether the cerebral blood flow cbf values obtained by using a dynamic ctp technique with a tracer delayinsensitive deconvolution algorithm are more accurate than those obtained by using ctp with delaysensitive algorithms in unilateral cerebrovascular stenoocclusive disease. The primary application of brain perfusion imaging in ct is to determine if the patient has had a stroke and to assess the viability of the brain tissue. Canon is on the left and ge healthcare is on the right. Reliability of ct perfusion ctp algorithms has not been fully validated. The derived cta images from ctp data are delayinsensitive because they display maximal contrast enhancement over time temporal maximum intensity projection, tmip. Effect of extended ct perfusion acquisition time on ischemic. Ischemic core was defined as reduction in cbf to ct brain perfusion isp uses a delay sensitive algorithm. Computed tomographic ct perfusion imaging has been increasingly advocated as a means of patient selection for advanced treatment of acute stroke and vasospasm but the optimal postprocessing algorithms for defining infarct core irreversibly dead brain and ischemic penumbra atrisk potentially salvageable brain tissue have yet to be determined. Timinginvariant ct angiography derived from ct perfusion. The goal of this study was to compare delay sensitive and delay insensitive deconvolution pct in.
Arterial input function placement for accurate ct perfusion. Ct perfusion in ischemic stroke radiology reference article. Introduction tracer delay sensitive perfusion algorithms in ct perfusion ctp result in an overestimation of the extent of ischemia in thromboembolic stroke. Delayinsensitive deconvolution software ct perfusion 4d, ge healthcare was used for ctp processing. Delaysensitive and delayinsensitive deconvolution perfusion. These 2 software packages represent the 2 mainstream algorithms. The purpose of this study was to assess the variability of the area of infarct core and penumbra as presented in summary maps produced by 2 different software packages. Penumbral imaging by using perfusion computed tomography and. Delaysensitive and delayinsensitive deconvolution perfusion ct.
Acute ischemic stroke is a disorder of blood flow to the brain, and its characterization and management typically require an answer to the following 4 critical questions. Comparison of perfusion ct software to predict the final infarct volume after thrombectomy. Ct perfusion was performed on a multidetector scanner ge healthcare, tokyo, japan, as a 60. Read differences in ct perfusion summary maps for patients with acute ischemic stroke generated by 2 software packages, american journal of neuroradiology on deepdyve, the largest online rental service for scholarly research with thousands of academic publications available at your fingertips. Delay insensitive brain perfusion analysis canon medical systems. Evaluation of perfusion abnormalities may be crucial for expanding the time window of the thrombolytic therapy beyond 3 hours. Computed tomography perfusion measurements in renal.
Ct brain perfusion 2d workflow is a convenient method of assessing perfusion disturbances within the brain. However, as this case demonstrates, small infarcts can be. B ctcbv map appears normal when postprocessed using newer generation, delayinsensitive software. These results highlight the delay insensitive nature of perfusion maps derived from maximumslope algorithms. The ct perfusion data sets were transferred to two different workstations to construct cbf, cbv, and mtt maps using standard methods with two commercially available software packages based on deconvolution techniques. The official history of computed tomography perfusion ctp began in 1979 when heinz and his colleagues published their paper.
Ischemic core was defined as reduction in cbf to ct brain perfusion isp uses a delaysen. To examine the variability in the qualitative and quantitative results of computed tomographic ct perfusion imaging generated from identical source data of stroke patients by using commercially available software programs provided by various ct manufacturers. One hundred sixtyeight ct perfusion maps were constructed for each software package. Ischemic core was defined as reduction in cbf to ct brain perfusion isp uses a delay sen. Using the delayinsensitive bayesian method for hemodynamic parameters estimation. Different ct perfusion algorithms in the detection of delayed. Arterial input function and venous output function ento key. Arterial input function placement for accurate ct perfusion map. Jan 16, 20 this study aims to assess the diagnostic accuracy of a single vendor commercially available ct perfusion ctp software in predicting stroke. It can help to standardise the method to figure out. Package a brain ct perfusion package philips healthcare, the netherlands, extended brilliance workspace, version 3. Tracer delayinsensitive algorithm can improve reliability of.
Delay sensitive deconvolution does not correct for arrival delay of contrast, whereas delay insensitive deconvolution does. Ischemic core is diagnosed if the relative cbf is ct perfusion is a promising tool to support treatment decisions for patients with acute ischemic stroke, it still lacks a standardized method for ctp analysis. Temporal changes in bloodbrain barrier permeability and. Here, we determine the dependency of computed tomography ct perfusion ctp t max estimates on tracer delay using a range of deconvolution techniques and digital phantoms. It enables differentiation of salvageable ischemic. Accuracy of ct cerebral perfusion in predicting infarct in. Karaalioglu b, aralasmak a, toprak h, kolukisa m, uysal o, yildiz s, ozdemir h, alkan a. This study aims to identify regions misclassified as ischemic core on ctp, using infarct on followup noncontrast ct. Hypoperfusion is defined as a relative mtt 145% compared with the contralateral hemisphere. Importantly, potential area of ischemic penumbra is visualized with both aif locations using software a. Ct perfusion in ischemic stroke has become established in most centers with stroke services as an important adjunct, along with ct angiography cta, to conventional unenhanced ct brain imaging. Accuracy and reliability assessment of ct and mr perfusion. Blood enters the brain via the arteries and then flows to the capillaries where oxygen is released to the brain tissue.
Rapid is a novedous system of analysis of ct perfusion that provides you exact volume of damage core infarct and mismatch penumbra. Ischemic core was defined as reduction in cbf to software ct perfusion 4d. Brain ct perfusion package philips healthcare, the netherlands. Unfortunately, software packages differ in how the perfusion maps are calculated and how the segmentations are performed. Source images were transferred to a workstation and were evaluated with ct perfusion 3 software ge healthcare. Background and purpose it has been suggested that ct perfusion acquisition times perfusion ct figure 1. Comparison with quantitative singlephoton emission ct. For example, whereas one software may generate highly delaysensitive mtt maps, other packages may generate delayinsensitive maps. Cerebral microvascular abnormality is frequently associated with lacunar and subcortical ischemic lesions. Two examples of ct myocardial perfusion ctp imaging assessment software. H, s1, s2, and pm2, which indicates delay insensitivity of these programs. Arterial input function and venous output function soren christensen matus straka tingyim lee introduction the role of the arterial input function and venous output function in perfusion measurements the arterial input function aif is the concentrationtime curve of the contrast agent indicator measured in an arterial vessel that feeds the organ of interest. Jul 14, 20 a new deconvolution algorithm, the bayesian estimation algorithm, was reported to improve the precision of parametric maps created using perfusion computed tomography.
Delay insensitive svd algorithm for perfusion analysis wang. Computed tomography perfusion ctp is a functional imaging technique used to visualize and quantify tissue perfusion and vascularity. The ctp parameters relative mtt and cbv distinguish the hypoperfusion and the ischemic core. Using the delay insensitive bayesian method for hemodynamic parameters estimation. Although ct perfusion is a promising tool to support treatment decisions for patients with acute ischemic stroke, it still lacks a standardized method for ctp analysis. Ischemic core was defined as reduction in cbf to ct brain perfusion isp uses a delaysensitive algorithm. The ctp parameters relative mtt and cbv distinguish the hypoperfusion and the. The study by kudo et al has demonstrated that software with delaysensitive deconvolution algorithms overestimate penumbra ie, mean transit. Digital phantom data sets simulating the tracer delay were created from ctp data of six healthy individuals, in which time frames of the left cerebral hemisphere were.
At present, however, there remains insufficient evidence to suggest whether maximumslope methods outperform delay insensitive deconvolution algorithms. Characteristics of misclassified ct perfusion ischemic core. Timinginvariant ct angiography derived from ct perfusion imaging in acute stroke. The ctps of 45 patients were retrospectively processed with 2 different methods. Two postprocessing software programs were used to evaluate the effect of aif placement on perfusion parameters using a delayinsensitive deconvolution.
Comparison of perfusion ct software to predict the. In ct perfusion, cbf maps fig 2a showed delaydependent variation for g1, p1, p2, t1, t2. Both of these technologies have been around for a few years, but there have been an increasing amount of clinical data from studies showing the accuracy of the technology compared to nuclear imaging, the current stand of care for myocardial perfusion. Tracer delayinsensitive algorithm can improve reliability of ct. Comparison of delaysensitive and delayinsensitive computed tomography perfusion. All software packages use automated registration, segmentation, and motion correction.
January 22, 2010 a new study from japan has found significant differences in the ways that five different commercial software packages assess abnormal brain regions on ct perfusion scans. Previous reports demonstrated that abnormal cbf decrease correlated well with the final infarct in the case of the delay insensitive ms method by using ct perfusion imaging and delay corrected svd by using magnetic resonance mr perfusion, while the final infarct size was overestimated by using svd with ct perfusion imaging and mr perfusion. Assessment of the accuracy of a bayesian estimation. Tracer delay insensitive algorithm can improve reliability of ct perfusion imaging for cerebrovascular stenoocclusive disease.
487 1502 269 1531 170 625 44 309 351 1530 129 1442 1225 739 467 1508 134 925 153 1419 310 922 1228 405 1334 1511 516 585 695 1574 172 1489 1206 1238 313 1467 536 1462 680 982 79 297 662 723 165 964