scholarly journals Arterial Input Function Placement for Accurate CT Perfusion Map Construction in Acute Stroke

2010 ◽  
Vol 194 (5) ◽  
pp. 1330-1336 ◽  
Author(s):  
Rafael M. Ferreira ◽  
Michael H. Lev ◽  
Gregory V. Goldmakher ◽  
Shahmir Kamalian ◽  
Pamela W. Schaefer ◽  
...  
Keyword(s):  
Acute Stroke ◽  
Arterial Input Function ◽  
Ct Perfusion ◽  
Input Function ◽  
Map Construction

Abstract W P27: Quantitative Measurement Of Blood Flow Around Intravascular Thrombus Using CT Perfusion T0 Maps

Stroke ◽  
2015 ◽  
Vol 46 (suppl_1) ◽  
Author(s):  
Seong Hwan Ahn ◽  
Christopher D. d’Esterre ◽  
Emmad M Qazi ◽  
Mayank Goyal ◽  
Andrew M Demchuk ◽  
...  
Keyword(s):  
Blood Flow ◽  
Predictive Value ◽  
Arterial Input Function ◽  
Ct Perfusion ◽  
Regression Line ◽  
Input Function ◽  
Positive Slope ◽  
Arterial Tree ◽  
Stroke Imaging ◽  
Iv Tpa

Introduction: Anterograde blood flow around thrombus and extent of retrograde collateral filling can affect thrombus lysis with IV tPA. Current assessment of blood flow around thrombus is however very subjective. The aim of the present study is to validate a newly devised method to quantify blood flow around thrombus using CT perfusion (CTP) T0 maps. Methods: From the Prove-IT stroke-imaging database, perfusion CT and DSA images of stroke patients treated with IV tPA and/or IA thrombolysis were analyzed. We generated maps that measure delay in arrival time of contrast within the intracranial arterial tree (T0 maps) from that of the chosen arterial input function. A “positive sloped” regression line of T0 values from distal clot interface to at least 14 pixels (median 68 pixels) along the artery profile indicated presence of occult anterograde flow. Anterograde flow thus measured using the T0 maps was compared with anterograde flow assessed on first angiography of subsequent IA procedure. Results: Of 37 patients (mean age 66 ± 13.5 years, 20 female), 35 (94.6%) were treated with IV tPA before DSA. Median time from CTP to first run angiography was 83 mins (IQR 53-100 mins). Positive slope were noted in 10 patients. Patients who had anterograde flow on first angiography were 10. Compared with anterograde flow on first run angio, positive slope on T0 map had a sensitivity of 80%, specificity of 92.6% and a positive predictive value of 80% and negative predictive value of 92.6%. In patients with anterograde flow on first angiography, median T0 time at proximal clot interface was 0.1 seconds (IQR 0-0.1) and at distal clot interface was 0.7 seconds (IQR 0.5-3.1). In patients without any anterograde flow on first angio, median T0 time at proximal clot interface was 0.1 seconds (IQR 0-0.3) while that at distal clot interface was 3.7 seconds (IQR 2.1-5.6). Conclusions: The slope method on CTP T0 maps and measurement of T0 values around clot reliably measure presence of anterograde blood flow through thrombus.

scholarly journals Susceptibility of Tmax to Tracer Delay on Perfusion Analysis: Quantitative Evaluation of Various Deconvolution Algorithms Using Digital Phantoms

2010 ◽  
Vol 31 (3) ◽  
pp. 908-912 ◽  
Author(s):  
Kohsuke Kudo ◽  
Makoto Sasaki ◽  
Leif Østergaard ◽  
Soren Christensen ◽  
Ikuko Uwano ◽  
...  
Keyword(s):  
Arterial Input Function ◽  
Ct Perfusion ◽  
Region Of Interest ◽  
Input Function ◽  
Residue Function ◽  
Data Sets ◽  
Positive Linear Correlation ◽  
The Right ◽  
Value Decomposition ◽  
Digital Phantoms

The time-to-maximum of the tissue residue function ( Tmax) perfusion index has proven very predictive of infarct growth in large clinical trials, yet its dependency on simple tracer delays remains unknown. Here, we determine the dependency of computed tomography (CT) perfusion (CTP) Tmax estimates on tracer delay using a range of deconvolution techniques and digital phantoms. 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 shifted forward and backward by up to ±5 seconds. These phantoms were postprocessed with three common singular value decomposition (SVD) deconvolution algorithms—standard SVD (sSVD), block-circulant SVD (bSVD), and delay-corrected SVD (dSVD)—with an arterial input function (AIF) obtained from the right middle cerebral artery (MCA). The Tmax values of the left hemisphere were compared among different tracer delays and algorithms by a region of interest-based analysis. The Tmax values by sSVD were positively correlated with ‘positive shifts’ but unchanged with ‘negative shifts,’ those by bSVD had an excellent positive linear correlation with both positive and negative shifts, and those by dSVD were relatively constant, although slightly increased with the positive shifts. The Tmax is a parameter highly dependent on tracer delays and deconvolution algorithm.

scholarly journals Normative distribution of posterior circulation tissue time-to-maximum: Effects of anatomic variation, tracer kinetics, and implications for patient selection in posterior circulation ischemic stroke

2021 ◽  
pp. 0271678X2098239
Author(s):  
Adam E Goldman-Yassen ◽  
Matus Straka ◽  
Michael Uhouse ◽  
Seena Dehkharghani
Keyword(s):  
Ischemic Stroke ◽  
Selection Criteria ◽  
Arterial Input Function ◽  
Anatomic Variation ◽  
Input Function ◽  
Posterior Circulation ◽  
Anterior Circulation ◽  
Vessel Occlusion ◽  
Perfusion Time

The generalization of perfusion-based, anterior circulation large vessel occlusion selection criteria to posterior circulation stroke is not straightforward due to physiologic delay, which we posit produces physiologic prolongation of the posterior circulation perfusion time-to-maximum (Tmax). To assess normative Tmax distributions, patients undergoing CTA/CTP for suspected ischemic stroke between 1/2018-3/2019 were retrospectively identified. Subjects with any cerebrovascular stenoses, or with follow-up MRI or final clinical diagnosis of stroke were excluded. Posterior circulation anatomic variations were identified. CTP were processed in RAPID and segmented in a custom pipeline permitting manually-enforced arterial input function (AIF) and perfusion estimations constrained to pre-specified vascular territories. Seventy-one subjects (mean 64 ± 19 years) met inclusion. Median Tmax was significantly greater in the cerebellar hemispheres (right: 3.0 s, left: 2.9 s) and PCA territories (right: 2.9 s; left: 3.3 s) than in the anterior circulation (right: 2.4 s; left: 2.3 s, p < 0.001). Fetal PCA disposition eliminated ipsilateral PCA Tmax delays (p = 0.012). Median territorial Tmax was significantly lower with basilar versus any anterior circulation AIF for all vascular territories (p < 0.001). Significant baseline delays in posterior circulation Tmax are observed even without steno-occlusive disease and vary with anatomic variation and AIF selection. The potential for overestimation of at-risk volumes in the posterior circulation merits caution in future trials.

P4-194: Blood Flow-Independent Quantification of [18F]-AV45 PET Using Model-Based Kinetics With a Metabolite-Corrected Arterial Input Function

2016 ◽  
Vol 12 ◽  
pp. P1097-P1098
Author(s):  
Julie Ottoy ◽  
Jeroen Verhaeghe ◽  
Ellis Niemantsverdriet ◽  
Leonie Wyffels ◽  
Charisse Somers ◽  
...  
Keyword(s):  
Blood Flow ◽  
Arterial Input Function ◽  
Input Function ◽  
Model Based
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