Role of Mean Transit Time (MTT) Perfusion Map on the Aquilion ONE CT Scanner Using SVD+ Algorithm in Acute Stroke (P07.035)

Background: During the first hours after stroke onset, tissue perfusion in stroke patients may undergo a highly dynamic phase of instability. We examined the characteristics of this perfusion instability (improvement and deterioration) and its impact on tissue outcome. Methods: Mean transit time (MTT) and FLAIR maps were obtained in 45 acute stroke patients (mean NIHSS: 14; 73% received IV tPA) at 3.0 hrs (tp1), 6.4 hrs (tp2), and 1 month after onset. MTT prolongation (pMTT) was calculated as: MTT - (median MTT of the non-ischemic hemisphere). Tissue was classified into three subtypes: stable ( Methods: Mean transit time (MTT) and FLAIR maps were obtained in 45 acute stroke patients (mean NIHSS: 14; 73% received IV tPA) at 3.0 hrs (tp1), 6.4 hrs (tp2), and 1 month after onset. MTT prolongation (pMTT) was calculated as: MTT - (median MTT of the non-ischemic hemisphere). Tissue was classified into three subtypes: stable (|pMTT tp2-tp1| ≤ 2 sec), improving (pMTT tp2-tp1< -2 sec), and deteriorating (pMTT tp2-tp1>2 sec) perfusion. Percent volume was computed as: (the # of voxels of a tissue subtype/total # of voxels at a specific tp1 pMTT) for each subtype and their infarct probabilities (IP) were graphed (Fig A and B). To further evaluate perfusion change and the corresponding impact on IP, a 3D plot of IP (color axis, Fig. C) as a function of pMTT tp1 and tp2 was generated, pooling voxels from all patients. Results: Early perfusion instability (within 6.5 hrs) was observed in 70-85% of total volume at a specific tp1 pMTT (50-60% improving and 20-30% deteriorating perfusion) for a range of tp1 pMTT of 3-21 sec (Fig. A). Differences in IP were observed among the three tissue subtypes for pMTT 3-17 sec, while IPs were similar at small pMTT (< 3 sec) and large pMTT (>17 sec), (Fig. B). For pMTT of 3-17 sec, IP was highly dependent on perfusion changes at tp2 (Fig. C). For example, IP for voxels starting with pMTT of 12sec at tp1 ranged from 35-95% depending on perfusion change at tp2 (Fig. C, vertical blue line). Conclusions: Early perfusion changes profoundly impact tissue viability, especially with initial pMTT ranging from 3-17 sec (likely representing penumbral range). Acute stroke therapies may be effective not only by promoting reperfusion, but also by preventing deteriorating perfusion.

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The effects of hypercapnia on cortical capillary transit time heterogeneity (CTH) in anesthetized mice

Journal of Cerebral Blood Flow & Metabolism ◽

10.1177/0271678x17692598 ◽

2017 ◽

Vol 38 (2) ◽

pp. 290-303 ◽

Cited By ~ 8

Author(s):

Eugenio Gutiérrez-Jiménez ◽

Hugo Angleys ◽

Peter Mondrup Rasmussen ◽

Irene Klærke Mikkelsen ◽

Kim Mouridsen ◽

...

Keyword(s):

Transit Time ◽

Capillary Flow ◽

Mean Transit Time ◽

Relative Increase ◽

Indicator Dilution ◽

Hemodynamic Responses ◽

Two Photon Microscopy ◽

Two Photon ◽

Coupling Mechanisms

Capillary flow patterns are highly heterogeneous in the resting brain. During hyperemia, capillary transit-time heterogeneity (CTH) decreases, in proportion to blood's mean transit time (MTT) in passive, compliant microvascular networks. Previously, we found that functional activation reduces the CTH:MTT ratio, suggesting that additional homogenization takes place through active neurocapillary coupling mechanisms. Here, we examine changes in the CTH:MTT ratio during hypercapnic hyperemia in anesthetized mice (C57Bl/6NTac), expecting that homogenization is smaller than during functional hyperemia. We used an indicator-dilution technique and multiple capillary scans by two-photon microscopy to estimate CTH and MTT. During hypercapnia, MTT and CTH decreased as derived from indicator-dilution between artery and vein, as well as between arterioles and venules. The CTH:MTT ratio, however, increased. The same tendency was observed in the estimates from capillary scans. The parallel reductions of MTT and CTH are consistent with previous data. We speculate that the relative increase in CTH compared to MTT during hypercapnia represents either or both capillary constrictions and blood passage through functional thoroughfare channels. Intriguingly, hemodynamic responses to hypercapnia declined with cortical depth, opposite previous reports of hemodynamic responses to functional activation. Our findings support the role of CTH in cerebral flow-metabolism coupling during hyperemia.

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Paradoxically Decreased Mean Transit Time in Patients Presenting With Acute Stroke

Journal of Computer Assisted Tomography ◽

10.1097/rct.0000000000000366 ◽

2016 ◽

Vol 40 (3) ◽

pp. 409-412 ◽

Cited By ~ 2

Author(s):

Cédric Doucet ◽

Federico Roncarolo ◽

Donatella Tampieri ◽

Maria del Pilar Cortes

Keyword(s):

Acute Stroke ◽

Transit Time ◽

Mean Transit Time

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Observer Agreement on Computed Tomography Perfusion Imaging in Acute Ischemic Stroke

Stroke ◽

10.1161/strokeaha.119.026238 ◽

2019 ◽

Vol 50 (11) ◽

pp. 3108-3114 ◽

Cited By ~ 2

Author(s):

Salwa El-Tawil ◽

Grant Mair ◽

Xuya Huang ◽

Eleni Sakka ◽

Jeb Palmer ◽

...

Keyword(s):

Computed Tomography ◽

Time Delay ◽

Acute Stroke ◽

Transit Time ◽

Delay Time ◽

Cerebral Blood Volume ◽

Mean Transit Time ◽

Observer Agreement ◽

Intraobserver Agreement ◽

Noncontrast Ct

Background and Purpose— Computed tomography (CT) perfusion (CTP) provides potentially valuable information to guide treatment decisions in acute stroke. Assessment of interobserver reliability of CTP has, however, been limited to small, mostly single center studies. We performed a large, internet-based study to assess observer reliability of CTP interpretation in acute stroke. Methods— We selected 24 cases from the IST-3 (Third International Stroke Trial), ATTEST (Alteplase Versus Tenecteplase for Thrombolysis After Ischaemic Stroke), and POSH (Post Stroke Hyperglycaemia) studies to illustrate various perfusion abnormalities. For each case, observers were presented with noncontrast CT, maps of cerebral blood volume, cerebral blood flow, mean transit time, delay time, and thresholded penumbra maps (dichotomized into penumbra and core), together with a short clinical vignette. Observers used a structured questionnaire to record presence of perfusion deficit, its extent compared with ischemic changes on noncontrast CT, and an Alberta Stroke Program Early CT Score for noncontrast CT and CTP. All images were viewed, and responses were collected online. We assessed observer agreement with Krippendorff-α. Intraobserver agreement was assessed by inviting observers who reviewed all scans for a repeat review of 6 scans. Results— Fifty seven observers contributed to the study, with 27 observers reviewing all 24 scans and 17 observers contributing repeat readings. Interobserver agreement was good to excellent for all CTP. Agreement was higher for perfusion maps compared with noncontrast CT and was higher for mean transit time, delay time, and penumbra map (Krippendorff-α =0.77, 0.79, and 0.81, respectively) compared with cerebral blood volume and cerebral blood flow (Krippendorff-α =0.69 and 0.62, respectively). Intraobserver agreement was fair to substantial in the majority of readers (Krippendorff-α ranged from 0.29 to 0.80). Conclusions— There are high levels of interobserver and intraobserver agreement for the interpretation of CTP in acute stroke, particularly of mean transit time, delay time, and penumbra maps.

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Evaluation of role of G-CSF in the production, survival, and release of neutrophils from bone marrow into circulation

Blood ◽

10.1182/blood.v100.3.854 ◽

2002 ◽

Vol 100 (3) ◽

pp. 854-861 ◽

Cited By ~ 156

Author(s):

Sunanda Basu ◽

George Hodgson ◽

Melissa Katz ◽

Ashley R. Dunn

Keyword(s):

Bone Marrow ◽

Steady State ◽

Transit Time ◽

Bone Marrow Cells ◽

Mean Transit Time ◽

Wild Type ◽

Blast Cells ◽

And Control ◽

Deficient Mice

Abstract In steady-state hematopoiesis, G-CSF (granulocyte-colony stimulating factor) regulates the level of neutrophils in the bone marrow and blood. In this study, we have exploited the availability of G-CSF–deficient mice to evaluate the role of G-CSF in steady-state granulopoiesis and the release of granulocytes from marrow into circulation. The thymidine analogue bromodeoxyuridine (BrdU) was used to label dividing bone marrow cells, allowing us to follow the release of granulocytes into circulation. Interestingly, the labeling index and the amount of BrdU incorporated by blast cells in bone marrow was greater in G-CSF–deficient mice than in wild-type mice. In blood, 2 different populations of BrdU-positive granulocytes, BrdUbright and BrdUdim, could be detected. The kinetics of release of the BrdUbright granulocytes from bone marrow into blood was similar in wild-type and G-CSF–deficient mice; however, BrdUdim granulocytes peaked earlier in G-CSF–deficient mice. Our findings suggest that the mean transit time of granulocytes through the postmitotic pool is similar in G-CSF–deficient and control mice, although the transit time through the mitotic pool is reduced in G-CSF–deficient mice. Moreover, the reduced numbers of granulocytes that characterize G-CSF–deficient mice is primarily due to increased apoptosis in cells within the granulocytic lineage. Collectively, our data suggest that at steady state, G-CSF is critical for the survival of granulocytic cells; however, it is dispensable for trafficking of granulocytes from bone marrow into circulation.

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Observation of Mean Transit Time (Mtt) Perfusion Maps on a 320-Detector Row Ct Scanner and its Potential Application in Acute Ischemic Stroke

Journal of Neurology & Neurophysiology ◽

10.4172/2155-9562.1000115 ◽

2011 ◽

Vol 02 (04) ◽

Cited By ~ 1

Author(s):

Haitham Dababneh ◽

Waldo Guerrero, ◽

Kelvin Wilson, ◽

J Duffy Mocco

Keyword(s):

Ischemic Stroke ◽

Acute Ischemic Stroke ◽

Transit Time ◽

Potential Application ◽

Mean Transit Time ◽

Ct Scanner ◽

Perfusion Maps

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The role of nursing in the rehabilitation of acute stroke patients: Toward a unified theoretical perspective

Pflege ◽

10.1024/1012-5302.12.1.21 ◽

1999 ◽

Vol 12 (1) ◽

pp. 21-27

Author(s):

Marit Kirkevold

Keyword(s):

Acute Stroke ◽

Theoretical Perspective ◽

Stroke Patients ◽

Role Of Nursing ◽

Rolle Der Pflegenden

Eine Übersicht der bestehenden Literatur weist auf Unsicherheiten bezüglich der spezifischen Rolle der Pflegenden in der Rehabilitation von Hirnschlagpatientinnen und -patienten hin. Es existieren zwei unterschiedliche Begrifflichkeiten für die Rolle der Pflegenden, keine davon bezieht sich auf spezifische Rehabilitationsziele oder Patientenergebnisse. Ein anfänglicher theoretischer Beitrag der Rolle der Pflege in der Genesung vom Hirnschlag wird als Struktur unterbreitet, um die therapeutischen Aspekte der Pflege im Koordinieren, Erhalten und Üben zu vereinen. Bestehende Literatur untermauert diesen Beitrag. Weitere Forschung ist jedoch notwendig, um den spezifischen Inhalt und Fokus der Pflege in der Genesung bei Hirnschlag zu entwickeln.

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